Real-time optical sensor and methods of use thereof

Abstract

An optical sensor includes an optical waveguide having at least one sensing region; and a detector configured to receive a return signal from the optical waveguide; wherein the at least one sensing region is capable of determining pH, temperature, dissolved oxygen concentration, glucose concentration, lactate concentration, NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS), or moisture level. The optical sensor can be particularly well-suited for determining or monitoring various parameters in real time. Methods of using the optical sensor are also provided.

Description

(UML 2024-007-02)REAL-TIME OPTICAL SENSOR AND METHODS OF USE THEREOFCROSS REFERENCE TO RELATED APPLICATIONThis application claims priority to U.S. Provisional Patent Application No. 63 / 762,740, filed on February 25, 2025, the contents of which are hereby incorporated by reference in their entirety.BACKGROUND

[0001] In the fast-evolving landscape of medical science and technology, bioprocessing systems stand out as transformative innovations. These systems are redefining the therapeutic options available to patients across the globe. Within the intricate tapestry of bioprocessing system production, especially during the cultivation of biopharmaceuticals, bacteria, yeast, or mammalian cells, vital reaction parameters such as pH, dissolved oxygen (DO), glucose, lactate, NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS) and temperature emerge as cornerstone elements. Their meticulous monitoring ensures not only the quality of the product but also the optimization of yield.

[0002] Moisture monitoring is another important aspect in several applications, such as agriculture, civil structural engineering, food processing and packaging, weather forecasting, and healthcare monitoring. There are several existing sensors for moisture monitoring, such as electrical-based, capacitive, resistive, mechanical hygrometers, etc. However, these existing measuring techniques have the disadvantages of bulky systems, are not immune to electromagnetic interference, which may distort the signal, are not feasible to be used in large- scale monitoring, etc.

[0003] There is a continuing need for improved sensors. It would be particularly advantageous to provide sensors capable of offering real-time, in-situ, multi -parameter insights.SUMMARY

[0004] A sensor comprises an optical waveguide having at least one sensing region formed on a portion thereof; a light source configured to provide an optical signal to the optical waveguide; and a detector configured to receive a signal from the optical waveguide; wherein the at least one sensing region is capable of determining pH, temperature, dissolved oxygen concentration, glucose concentration, lactate concentration, NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS) or moisture level.

[0005] A single use bioreactor comprises the sensor.(UML 2024-007-02)

[0006] A method for monitoring moisture level comprises: disposing an optical sensor in an area to be monitored; transmitting optical signals through the optical sensor from a light source to and from the at least one sensing region, wherein reflectance from the at least one sensing region varies with the moisture content of the sensing region; and measuring the returned light reflected by the sensing region.

[0007] A method for monitoring a bioprocess in a bioreactor comprises: disposing an optical sensor in a bioreactor; transmitting optical signals through the optical sensor from a light source to and from the at least one sensing region; and measuring the returned light reflected by the sensing region; wherein the transmitted light by the sensing region corresponds to at least one of pH, temperature, dissolved oxygen concentration, glucose concentration, lactate concentration, NAD+ / NADH, pressure, flow rate and reactive oxygen species (ROS) in the bioreactor.

[0008] The above described and other features are exemplified by the following figures and detailed description,BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The following figures are exemplary’ embodiments wherein the like elements are numbered alike.

[0010] FIG. 1A is a schematic illustration of a sensor according to an aspect of the disclosure.

[0011] FIG. 1B is a schematic illustration of a sensor according to an aspect of the disclosure.

[0012] FIG. 2A is a schematic illustration of a sensor according to an aspect of the disclosure.

[0013] FIG. 2B is a schematic illustration of a sensor according to an aspect of the disclosure.

[0014] FIG. 2C is a schematic illustration of a sensor according to an aspect of the disclosure.

[0015] FIG. 2D is a schematic illustration of a sensor according to an aspect of the disclosure.

[0016] FIG. 2E is a schematic illustration of a sensor according to an aspect of the disclosure.

[0017] FIG. 2F is a schematic illustration of a sensor according to an aspect of the disclosure.(UML 2024-007-02)

[0018] FIG. 2G is a schematic illustration of a sensor according to an aspect of the disclosure.

[0019] FIG, 3 A is a schematic illustration of a sensor in a bioreactor according to an aspect of the disclosure.

[0020] FIG. 3B is a schematic illustration of a sensor in a milliliter-scale shake flask according to an aspect of the disclosure.

[0021] FIG. 3C is a schematic illustration of a sensor in a single-use bioreactor bag according to an aspect of the disclosure.

[0022] FIG. 3D is a schematic illustration of a sensor in an Ambr™ 250 system according to an aspect of the disclosure,

[0023] FIG. 4A is a schematic illustration of a single use bioreactor having a sensor disposed therein according to an aspect of the disclosure.

[0024] FIG. 4B is a schematic illustration of a single use bioreactor having a sensor disposed therein according to an aspect of the disclosure,

[0025] FIG. 5 is a schematic illustration of a sensor according to an aspect of the disclosure

[0026] FIG, 6 is a schematic illustration of a sensor according to an aspect of the disclosure.

[0027] FIG. 7 is a schematic illustration of a sensor according to an aspect of the disclosure.

[0028] FIG. 8 is a schematic illustration of a sensor according to an aspect of the disclosure.

[0029] FIG. 9 is a schematic illustration of a sensor according to an aspect of the disclosure.

[0030] FIG. 10 is a schematic illustration of an experimental setup for testing a sensor according to an aspect of the disclosure.

[0031] FIG. 11 shows a plot of pH determined using a sensor according to an aspect of the present disclosure.

[0032] FIG. 12 is a schematic illustration of a sensor according to an aspect of the disclosure.

[0033] FIG. 13A shows a plot of spectral shift in a moisture sensing test.

[0034] FIG, 13B shows a plot of spectral shift in a moisture sensing test.

[0035] FIG, 14 shows a plot of spectral shift in a moisture sensing test.

[0036] FIG. 15 shows a plot of spectral shift in a moisture sensing test.(UML 2024-007-02)

[0037] FIG. 16 shows a plot of spectral shift in a moisture sensing test.

[0038] FIG. 17 shows a plot of spectral shift in a dual temperature and moisture sensing test.

[0039] FIG. 18 shows a schematic illustration of a coating on a surface of an optical waveguide according to an aspect of the present disclosure.

[0040] FIG. 19A shows LSPR sensing results of glucose solutions (transmission spectra; 300-1100 nm).

[0041] FIG. 19B shows LSPR sensing results of glucose solutions (transmission spectra; 653-660 nm).DETAILED DESCRIPTION

[0042] Currently, the market predominantly offers sensors designed with a narrow focus, specifically catering to individual parameters like pH, dissolved oxygen (DO), glucose, lactate, NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS) or temperature. This specialized approach, while precise, amplifies the intricacy of the production process. Each sensor, with its unique function, demands individualized setup and maintenance, thereby adding layers of complexity to the workflow.

[0043] Diving deeper into the realm of monitoring technologies for bioprocessing systems, they, along with their corresponding sensors, can be compartmentalized into three distinct types: offline, online, and in-line. This classification is predominantly based on their operational position within the system. Current sensor technologies are constrained by singleparameter detection, large size, and the need for frequent sample extraction. These limitations complicate integration and prevent real-time, in-situ monitoring, especially in milliliter-scale systems critical for early-stage research. Existing systems also struggle to meet the demands of continuous manufacturing and modular production facilities, where flexibility, scalability, and integration are essential. As the biopharmaceutical industry increasingly focuses on complex biologies, such as cell and gene therapies, the need for advanced sensing technologies is more pressing than ever. These therapies require precise, real-time monitoring of unique critical quality attributes, which the proposed sensor is uniquely positioned to deliver. By consolidating multi-parameter sensing into a single platform, the technology supports PAT and QbD goals, advancing biomanufacturing capabilities and addressing the evolving needs of the industry. Current multi-parameter sensor system in the market. In recent years, multi-parameter sensor systems have been developed to address some challenges in bioprocessing. However, these systems come with significant limitations. They are typically large, expensive, and designed for(UML 2024-007-02)highly specialized applications, which restricts their scalability and limits their use in routine biomanufacturing processes. Their bulkiness poses challenges for integration into existing workflows, particularly in compact or disposable bioreactor systems, where space constraints and compatibility are critical. Additionally, these systems often require frequent recalibration and maintenance, resulting in substantial downtime and lost productivity during bioprocessing. Commercial at-line / offline multi-parameter cell-culture analyzers are widely used to profile culture performance because they can rapidly quantify key metabolites and physicochemical variables (e.g., glucose, lactate, pH, dissolved gases, cell density / viability, and osmolality) from small, discrete samples. However, because these platforms primarily operate on withdrawn aliquots rather than sensing in situ, they inherently introduce sampling latency and handling steps, and they do not provide continuous, spatially distributed data directly inside bioreactors. Even when sampling is automated, the workflow still relies on sample extraction and transfer to an external analy zer, which can limit responsiveness for truly closed-loop control - especially during fast process transients or across multiple vessels / locations. A multi -parameter optical waveguide sensor could address this gap by enabling real-time, in si tu monitoring of multiple parameters simultaneously at bioreactor-relevant locations, reducing the need for physical sample transport and supporting uniform, immediate data acquisition regardless of deck position.[00441 As conventional methods reach their limitations, in-line sensors are becoming increasingly popular. These sensors offer real-time, in-situ, multi-parameter insights, eliminating the immediate need for hefty investments in advanced equipment. Designed to meet the specific needs of bioprocessing systems, the evolution of these state-of-the-art sensors promises to drive further innovation in the field.

[0045] A sensor for real-time bioprocessing should be cost-effective, swift, sensitive, non-destructive, and robust. It must produce multi-analyte data without consuming samples or affecting the culture's metabolism and be resilient enough to thrive in the demanding sterile conditions of bioreactors. Optical sensors emerge as prime contenders in this scenario. They not only overcome existing challenges but also bring a multitude of benefits to the table. The following is an example of monitoring pH, DO, temperature, lactate concentration,NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS) and glucose concentration. Optical DO sensors measure oxygen through luminescence quenching, giving them advantages over traditional methods, such as less maintenance and no interference from other substances. For temperature measurements, any change in temperature modifies the FP cavity length through thermal expansion or contraction of the fiber's material, which then shifts the(UML 2024-007-02)interference spectrum. Optical pH sensors use pH-sensitive dyes to detect changes based on hydrogen ion concentrations. These sensors stand out for their continuous measurements and the ability to detect changes in materials exposed to varying pH levels. Optical glucose sensors, designed for bioreactor integration, monitor glucose concentrations by noting shifts in the optical attributes of glucose-sensitive indicators, ensuring stable, continuous data collection. Similarly, optical fiber sensors immobilized with lactate oxidase are tailored for lactate monitoring applications.

[0046] Guided by this perspective, the present inventors have developed a Smart In-line Real-Time Multi-Parameter Sensing System (IRTMPSS) using an optical fiber sensor.Advantageously, the sensor according to the present disclosure is a flexible, compact, multiparameter sensor capable of real-time data acquisition for multiple parameters. Thus the sensor provided herein can address certain challenges faced by existing sensors, which are generally bulky with a fixed number of ports and capable of measuring single parameters.

[0047] Accordingly, an aspect of the present disclosure is a sensor comprising an optical fiber (or waveguide) having at least one sensing region formed on a portion thereof; a light source configured to provide an optical signal to the optical waveguide; and a detector configured to receive a return signal from the optical waveguide.

[0048] The at least one sensing region is capable of determining pH, temperature, dissolved oxygen concentration, glucose concentration, lactate concentration, NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS), or moisture level. In an aspect, the sensor comprises at least one pH sensing region. In an aspect, the sensor comprises at least one temperature sensing region. In an aspect, the sensor comprises at least one moisture sensing region. In an aspect, the sensor comprises at least one dissolved oxygen sensing region, in an aspect, the sensor comprises at least one glucose sensing region. In an aspect, the sensor comprises at least one lactate sensing region.

[0049] A sensor may comprise any combination of the foregoing sensing regions.Accordingly, in some aspects, multiple sensing regions can be present on the optical waveguide to simultaneously detect multiple parameters. For example, in an aspect the optical waveguide can comprise a first sensing region, a second sensing region, optionally a third sensing region, optionally a fourth sensing region, optionally a fifth sensing region, optionally a sixth sensing region, optionally a seventh sensing region, and optionally an eighth sensing region. Any number of the foregoing optional sensing regions may be present. Additional sensing regions (e.g., beyond eight) are also contemplated by the present disclosure. The number of sensing regions can vary based on tire desired application and can be suitably determined by the skilled(UML 2024-007-02)person based on the present disclosure.

[0050] Each sensing region, when multiple sensing regions are present, can be independently capable of detecting a parameter selected from pH, temperature, dissolved oxygen concentration, glucose concentration, lactate concentration, NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS), or moisture level. In an aspect, the sensor can comprise a first sensing region capable of determining pH and a second sensing region capable of determining temperature. In an aspect, the sensor can comprise a first sensing region, a second sensing region, optionally a third sensing region, and optionally a fourth sensing region, wherein each of the first, second, third, and fourth sensing regions are independently capable of determining pH, temperature, dissolved oxygen concentration, glucose concentration, or lactate concentration.

[0051] Tire sensing mechanism employed in the sensing region can utilize various optical techniques such as fiber Bragg grating (FBG) reflection, long period Gratings (LPG), tapered fiber optical frequency domain reflectometry (OFDR), fluorescence methods, transmission spectroscopy, localized surface plasmon resonance (LSPR), or Fabry-Perot (FP) interferometry. Each technique is suitable for different types of measurements depending on the specific application requirements. In an aspect, the at least one sensing region can comprise a fiber Bragg grating, a Fabry-Perot interferometer, a tapered region, or a combination thereof.

[0052] Any suitable optical fiber or waveguide can generally be used. For example, the optical waveguide can comprise a single-mode fiber, a multimode fiber, coreless termination fiber, hollow core photonic crystal fiber or a plastic optical fiber.

[0053] The optical waveguide can comprise a suitable coating disposed on a surface of the waveguide at a select portion to form each desired sensing region. For example, in an aspect, the first sensing region can comprise a hydrogel coating on a portion of a surface of the optical fiber. Tire hydrogel can be a pH responsive hydrogel and exhibit a change in swelling at varying pH levels. In an aspect, the hydrogel can comprise polyacrylamide. In an aspect, the pH-sensitive material forming the coating of a pH sensing region can comprise a hydrogel and fluorescent pH probe including, but not limited to, pyrene and derivatives thereof such as 8-hydroxypyrene- 1,3, 6-tri sulfonic acid. Any suitable fluorescent probe can be used provided that a change in pH of the environment triggers a change in fluorescence intensity.

[0054] In an aspect, the at least one sensing region can be capable of determining moisture level and can comprise a moisture sensitive coating disposed on a surface of the optical fiber. The moisture sensitive coating can be formed from any material that exhibits a detectable optical response such as a change in swelling, refractive index, absorption, or scattering upon exposure to water molecules. For example, the coating can comprise carbon black. In some(UML 2024-007-02)aspects, the moisture sensitive coating can comprise a hygroscopic polymeric material, including but not limited to polyvinyl alcohol (PVA), polyimide, cellulose-based materials (e.g., hydroxyethyl cellulose), or hydrogel -forming polymers that undergo volumetric expansion in the presence of moisture. In still further aspects, the coating can comprise metal-oxide materials such as zinc oxide (ZnO), titanium dioxide (TiO2), or aluminum oxide (Al2O3), which may exhibit moisture-dependent refractive index shifts. Additional suitable moisture-responsive coatings include graphene oxide, which provides high surface area and humidity-dependent conductivity and intensity variation, and porous silica or sol-gel-derived films capable of adsorbing water vapor. Any material capable of producing an optical change such as a wavelength shift, intensity’ change, or refractive index variation correlated with moisture content may be used to form the moisture-sensitive coating.

[0055] In some embodiments, the at least one sensing region can be configured to determine dissolved oxygen (DO) concentration and comprises an oxygen-sensitive luminescent reporter. Non-limiting examples of suitable reporters include ruthenium-based complexes (e.g., tris(4,7-diphenyl-l,10-phenanthroline)ruthenium(II) and tris(2,2’-bipyridyl)ruthenium(II)) that exhibit oxygen-dependent luminescence quenching. In further embodiments, platinum(II) and / or palladium(II) porphyrin -based dyes (e.g., platinum(II) octaethylporphyrin (PtOEP) and palladium(II) meso-tetraphenylporphyrin (PdTPP)) may be used due to strong phosphorescence and high sensitivity to dynamic quenching by dissolved oxygen. The DO reporter can be embedded within a matrix material forming a coating on a surface of the optical waveguide, The matrix may comprise, without limitation, a polymer matrix, a silicon -containing material (e.g., derived from one or more alkyl silanes), or a fluoropolymer.

[0056] In some aspects, the coating material on a surface of the optical wav eguide can comprise more than one material, optionally w’herein each material is disposed in a layer (e.g., a multilayer coating can form the sensing region). For example, in an aspect, the at least one sensing region capable of determining glucose concentration can comprise graphene oxide, gold nanoparticles, polyethylene glycol, and glucose oxidase. In an aspect, the at least one sensing region can comprise a first layer comprising graphene oxide on the optical waveguide, a second layer comprising gold nanoparticles on the first layer, a third layer comprising a polymer (preferably a biocompatible polymer such as polyethylene glycol) on the second layer, and a fourth layer comprising glucose oxidase on the third layer. In an aspect, the at least one sensing region capable of determining lactate concentration comprises graphene oxide, silver nanoparticles, polyethylene glycol, and lactate oxidase. In an aspect, the at least one sensing region can comprise a first layer comprising graphene oxide on the optical waveguide, a second(UML 2024-007-02)layer comprising silver nanoparticles on the first layer, a third layer comprising a polymer (preferably a biocompatible polymer such as poly(ethylene glycol)) on the second layer, and a fourth layer comprising lactate oxidase on the third layer.

[0057] In an aspect, the detector can comprise a Raman scattering detector or a spectrometer. In an aspect, the light source and the detector can be housed in a single unit, preferably an optical frequency domain reflectometer.

[0058] The sensor can be used in combination with, for example, a bioreactor.Accordingly, another aspect is a bioreactor comprising the sensor of the present disclosure. The bioreactor can be selected from any suitable bioreactor type and the present disclosure should not be construed as limited to a particular design or configuration. Bioreactors useful with the disclosed optical sensor can include, but are not limited to, stirred-tank bioreactors, air-lift bioreactors, bubble-column bioreactors, fluidized-bed bioreactors, packed-bed (fixed-bed) bioreactors, perfusion bioreactors, wave-induced (rocking-motion) bioreactors, hollow-fiber bioreactors, and photobioreactors. Bioreactors may be manufactured from stainless steel, plastic (e.g., polymer materials), glass, or composite materials, and may be operated in batch, fed-batch, continuous, or perfusion modes.

[0059] In some aspects, the bioreactor is a single-use bioreactor, such as a polymeric bag -based system. The optical fiber can be integrated into the single-use bioreactor in any suitable manner, including spiral-wound configurations or linear placements along an internal surface of the vessel.

[0060] In other aspects, for example for a fermenter or cell-culture vessel, i.e., a shake flask or miniature automated system (e.g., an Ambr™ 250 system), the sensor may also be used with systems designed for microbial fermentation, mammalian cell culture, plant cell cultivation, or tissue engineering, including systems requiring low shear, high oxygen transfer, or specialized illumination (e.g., photobioreactors).

[0061] The optical sensor of the present disclosure can be incorporated into any reactor geometry or operational mode provided that an optical path can be established along the fiber and the sensing region(s) can contact or be exposed to the target environment. The compatibility of the optical sensor with diverse bioreactor formats, including both fixed and disposable systems, allows real-time, in-situ, multi-parameter monitoring across a broad range of bioprocessing applications.

[0062] Another aspect is a method for monitoring moisture level. The method comprises disposing the optical fiber sensor according to the present disclosure in an area to be monitored, transmitting optical signals through the optical fiber sensor from a light source to and from the at(UML 2024-007-02)least one sensing region, wherein reflectance from the at least one sensing region varies with the moisture content of the sensing region, and measuring the returned light reflected by the sensing region. In an aspect the method can further comprise detecting changes in the returned light reflected by the sensing region corresponding to a change in moisture level. In an aspect, the moisture can be measured continuously. In an aspect, the moisture can be measured in real time.

[0063] Another aspect is a method for monitoring a bioprocess in a bioreactor. The method comprises disposing an optical fiber sensor according to the present disclosure in a bioreactor; transmitting optical signals through the optical fiber sensor from a light source to and from the at least one sensing region; and measuring the returned light reflected by the sensing region; wherein the returned light reflected by the sensing region corresponds to at least one of pH, temperature, dissolved oxygen concentration, or glucose concentration in the bioreactor. In an aspect the bioprocess can be monitored continuously. In an aspect, the bioprocess can be monitored in real time. In an aspect, the bioreactor can be a single use bioreactor.

[0064] Another aspect is a method for monitoring pH, The method comprises disposing the optical fiber sensor according to the present disclosure in an area to be monitored, transmitting optical signals through the optical fiber sensor from a light source to and from the at least one sensing region, wherein reflectance from the at least one sensing region varies with the pH of the sensing region, and measuring the returned light reflected by the sensing region. In an aspect the method can further comprise detecting changes in the returned light reflected by the sensing region corresponding to a change in pH. In an aspect, the pH can be measured continuously. In an aspect, the pH can be measured in real time.

[0065] Another aspect is a method for monitoring dissolved oxygen concentration. The method comprises disposing the sensor according to the present disclosure in an area to be monitored, transmitting optical signals through the sensor from a light source to and from the at least one sensing region, wherein reflectance from the at least one sensing region varies with the dissolved oxygen concentration of the sensing region, and measuring the returned light reflected by the sensing region. In an aspect the method can further comprise detecting changes in the returned light reflected by the sensing region corresponding to a change in dissolved oxygen concentration. In an aspect, the dissolved oxygen concentration can be measured continuously. In an aspect, the dissolved oxygen concentration can be measured in real time.

[0066] Another aspect is a method for monitoring glucose concentration. The method comprises disposing the sensor according to the present disclosure in an area to be monitored, transmitting optical signals through the sensor from a light source to and from the at least one sensing region, wherein reflectance from the at least one sensing region varies with tire glucose(UML 2024-007-02)concentration of the sensing region, and measuring the returned light reflected by the sensing region. In an aspect the method can further comprise detecting changes in the returned light reflected by the sensing region corresponding to a change in glucose concentration. In an aspect, the glucose concentration can be measured continuously. In an aspect, the glucose concentration can be measured in real time.

[0067] Another aspect is a method for monitoring lactate concentration. The method comprises disposing the sensor according to the present disclosure in an area to be monitored, transmitting optical signals through the sensor from a light source to and from the at least one sensing region, wherein reflectance from the at least one sensing region varies with the lactate concentration of the sensing region, and measuring the returned light reflected by the sensing region. In an aspect the method can further comprise detecting changes in the returned light reflected by the sensing region corresponding to a change in lactate concentration. In an aspect, the lactate concentration can be measured continuously. In an aspect, the lactate concentration can be measured in real time.

[0068] Another aspect is a method for monitoring multiple parameters, wherein the multiple parameters include at least two parameters selected from pH, temperature, dissolved oxygen concentration, glucose concentration, lactate concentration, NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS), or moisture level. The method comprises disposing the sensor according to the present disclosure in an area to be monitored, transmitting optical signals through the sensor from a light source to and from at least two sensing regions, each sensing region independently configured to detect a parameter selected from pH, temperature, dissolved oxygen concentration, glucose concentration, lactate concentration, NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS), or moisture level. Reflectance from the at least two sensing regions varies with the at least two parameters (e.g., concentration, temperature, pH, etc.). The method further comprises measuring the returned light reflected by the sensing regions. In an aspect the method can further comprise detecting changes in the returned light reflected by the sensing regions corresponding to a change in one or more of the at least two parameters. In an aspect, the parameters can be measured continuously. In an aspect, the parameters can be measured in real time. In an aspect, the parameters can be measured simultaneously.

[0069] The sensors of the present disclosure will now be discussed further in reference to the accompanying Figures.

[0070] FIG. 1A and IB are schematic illustrations offering details regarding monitoring using optical waveguides and their role in the operation and performance evaluation. As shown(UML 2024-007-02)in FIG. 1A, an optical fiber (100) can include a pH sensing region (101), a temperature sensing region (102), a dissolved oxygen sensing region (103), a glucose sensing region (104), and a lactate sensing region (105). As shown in FIG, IB, an optical fiber (100) can include a pH sensing region (101), a temperature sensing region (102), a dissolved oxygen sensing region (103), a glucose sensing region (104), a lactate sensing region (105), a NAD+ / NADH sensing region (106), a ROS sensing region (107), and a pressure / flow rate sensing region (108).

[0071] The system can incorporate a variety of advanced fiber-optic technologies, supporting not only single-mode fibers (SMF), multimode fibers, coreless termination fiber, hollow core photonic crystal fiber and specialty fibers but also compatible with plastic optical fibers (POF). To ensure the highest accuracy in detection and cater to diverse application needs, the present system can be equipped with various devices, including Raman scattering technology, optical frequency domain reflectometry (OFDR), spectrometers, fiber Bragg grating (FBG) interrogators, optical spectrum analyzer (OSA) and high-sensitivity detectors.

[0072] Within the domain of fiber-optic sensing, techniques such as Raman scattering, OFDR, Fabry-Perot (FP), long period gratings (LPG), fluorescence, tapered fiber and localized surface plasmon resonance (LSPR) and fiber Bragg grating (FBG) are preeminent, each proficiently measuring parameters like pH, DO, temperature, glucose and lactate, Raman scattering captures the distinctive scattering spectra from molecular vibrations and rotations, offering profound chemical insights. Meanwhile, OFDR pinpoints subtle light scattering and reflection changes within fibers, FP sensors hinge on interference patterns between reflective interfaces which shift with material variations, while FBG and LPG utilize variations in internal refractive index, with meticulously crafted gratings, to respond to environmental stimuli such as temperature shifts. Fluorescence techniques measure the emission resulting from light excitation, useful for detecting specific molecular interactions, LSPR leverages the resonant oscillation of conduction electrons at the surface of metal nanoparticles under light excitation to enhance the detection of biochemical interactions. Integral to these techniques is the optical fiber's surface treatment, which might encompass specific coatings for enhanced sensitivity or specialized materials that react under varying conditions. Of course, these technologies can also be harmoniously integrated, resulting in a multifaceted, precision-driven fiber optic sensing system that brings a comprehensive and stable data solution for a variety of applications.

[0073] Most notably, to achieve more precise results in biopharmaceutical applications, the present inventors are delving deeper into surface-enhanced Raman scattering (SERS) spectroscopy and Tip-enhanced Raman spectroscopy (TERS), aiming to further elevate the system's overall performance and stability.(UML 2024-007-02)

[0074] FIG. 2A-2G illustrate various exemplary embodiments according to aspects of the present disclosure. In each of FIG. 2A-2G, the sensor includes an optical fiber (201), a pH sensing region (201), a temperature sensing region (202), a dissolved oxygen sensing region (203), a glucose sensing region (204), and a lactate sensing region (205). FIG 2A further shows a light source (206) and a spectrometer (207). FIG. 2B further shows an OFDR (208). FIG. 2C further shows a light source (206), a circulator (209), FBG interrogators (210), and a computer (211 ). Additionally, each of the pH sensing region (201), the temperature sensing region (202), the dissolved oxygen sensing region (203), the glucose sensing region (204), and the lactate sensing region (205) of FIG. 2C are adapted for FBG by inclusion of FBG sensors. FIG. 2D shows an optical fiber (201), a pH sensing region (201), a temperature sensing region (202), a dissolved oxygen sensing region (203), a glucose sensing region (204), a lactate sensing region (205), a light source (206) and a spectrometer (207), where each of the pH sensing region (201), the temperature sensing region (202), the dissolved oxygen sensing region (203), the glucose sensing region (204), and the lactate sensing region (205) of FIG. 2D include an FP cavity. FIG.2E shows an optical fiber (200) including a pH sensing region (201), a temperature sensing region (202), a dissolved oxygen sensing region (203), a glucose sensing region (204), a lactate sensing region (205), a NAD+ / NADH sensing region (206), a ROS sensing region (207), and a pressure / flow rate sensing region (208), and further includes a light source (206), a circulator (209), a filter (212), a spectrometer (207) and a computer (211). FIG. 2F shows an optical fiber (201), a pH sensing region (201), a temperature sensing region (202), a dissolved oxygen sensing region (203), a glucose sensing region (204), a lactate sensing region (205), a light source (206) and a spectrometer (207), where each of the pH sensing region (201), the temperature sensing region (202), the dissolved oxygen sensing region (203), the glucose sensing region (204), and the lactate sensing region (205) of FIG. 2F are adapted for LPG sensing. FIG. 2G depicts a sensor where each sensing region may be configured for different types of sensing. For example, the temperature sensing region (202) can include a FP cavity, the DO sensing region (203) can include FBG gratings, the glucose sensing region (204) can be tapered, and the lactate sensing region (205) can be adapted for LPG sensing.

[0075] In an aspect, the sensor may achieve simultaneous monitoring of glucose and lactate. FIG. 3A-3D illustrates various scenarios, wherein FIG. 3 A illustrates use of a bioreactor, FIG. 3B, illustrates use of milliliter-scale shake flasks, FIG. 3C illustrates single-use bioreactor bags, and FIG, 3D illustrates use of an AmbrTM250 system. Tire sensors may have any combination of the foregoing sensing regions, such as shown in FIG. 2A-2G.

[0076] The bioprocessing system trend is moving from fixed to disposable systems,(UML 2024-007-02)demanding concurrent advancements in sensor technology. Accordingly use of the presently disclosed sensor in conjunction with a single-use bioreactor (SUB) is also contemplated by the present disclosure, FIG, 4A and 4B represent different arrangements of optical fiber sensors according to the present disclosure in a SUB. For example, FIG. 4A shows that the fiber can be arranged along the inner surface of SUB from the bottom to the top spiral. Since the fiber is fixed to the SUB, it can be shrank and stretched up and down with the SUB, which is easier to store. FIG. 4B shows that the fiber can be fixed on the side, perpendicular to the bottom surface. When the SUB needs to be stored, it can be rolled up with the optical fiber sensor as the axis, saving space and the use of optical fiber.

[0077] The optical fiber can be integrated into the disposable bioreactor plastic bag with a connector provided at the end for signal collection. This integration makes the sensor system an integral part of the bioreactor, enabling true single-use capability and eliminating the risk of contamination. The user-friendly design facilitates easy connection and convenient sterilization processes, streamlining the experimental setup.

[0078] The present disposable bioreactor plastic bag, equipped with intelligent multiparameter sensors, presents both researchers and manufacturers with an economical yet robust solution for process monitoring and optimization. This design, which champions convenience, affordability, and contamination protection, stands poised to redefine the biopharmaceutical landscape, ushering in more streamlined and avant-garde methodologies. Simultaneously, it also augments the potential for the integration of such smart sensors across a wider spectrum of bioprocessing systems.

[0079] Another aspect of the present disclosure is a sensor for moisture monitoring. Existing measuring techniques have the disadvantages of bulky systems, are not immune to electromagnetic interference, which may distort the signal, are not feasible to be used in large-scale monitoring. In contrast to these techniques, optical sensors can provide real-time data while monitoring a large-scale field, providing the advantage of being immune to electromagnetic interference, easy to install in any form of structure or shape, and lightweight.

[0080] Optical sensors can be point sensors or distributed sensors. The limitations of optical point sensors are they can measure the sensing element only at a specific point and to sense the full sensing target, it requires more point sensors which introduces more cost to the total budget and also makes the circuit more complex. Distributed optical sensors not only overcome the limitations of point sensors but also provide a complete picture of the sensing target expressing current conditions. For these reasons, in large-scale moisture monitoring, distributed optical sensors are beneficial.(UML 2024-007-02)

[0081] Another problem is coating material to sense the moisture. While sensing with coating material, the materials have to be non-hazardous and not react with the sensing object. Cost is another factor that plays a significant role in choosing the coated material. Some sensing material degrades its performance if used for longer times. For this reason, stability and repeatability are important factors to be considered for analyzing any sensor performance. In some cases, existing sensors cannot monitor different amounts of moisture at a time using a single sensor, which is required in some applications where different portions have different moisture that needs to be measured to control and ensure the desired moisture level. Accuracy in measuring especially low moisture levels is another issue with existing sensors. Some sensors cannot provi de that sensitivity to sense the low level of moisture, which may be required in some applications such as food storage and pharmaceutical industry to ensure good quality of product.

[0082] To overcome the above-described technical limitations, the present inventors have discovered an optical fiber-based sensing approach can be used. The schematic for the reported sensor is illustrated in FIG. 5. In this schematic, the black portion indicates the sensing region with coating material on the optical fiber.

[0083] To sense a large area, this coated portion can be cascaded depending on the user’s need. The robustness of this presented sensing approach is using multiple sensing sections, one can sense different humidity levels at a time using only one fiber optic cable which may reduce the cost for discrete sensors as well as reduce the complexity of the whole system. This schematic is depicted in FIG. 6.

[0084] The coating material is not particularly limited provided that it is capable of sensing moisture. Exemplary coating material can include, but is not limited to, carbon black, hydrogel or any other thin film that can sense moisture contents. Moreover, this coating-based sensing approach can be used with different optical approaches such as Optical Frequency Domain Reflectometry (OFDR), tapered fiber, Long Period Fiber Gratings (LPFGs), spectrometers, Fiber Bragg Grating (FBG), Fabry-Perot interferometers (FPIs) etc. For example, a quasi -distributed FBG-based sensing approach can be constructed using multiple FBGs coated with any material that can sense moisture, grated on the optical fiber creating cascade structures. In this approach, an FBG strain sensor can be used in moisture measurement because when it is coated with hygroscopic material, the coated sensing region creates strain to the FBG as the region swells after exposure to humid environments. This strain effect causes a Bragg wavelength shift which can be used to determine the moisture level at that time. This approach is depicted in FIG. 7. Another quasi-distributed sensing approach for moisture monitoring is the FP(UML 2024-007-02)cavity-based approach where hygroscopic material swells after exposure to water molecules. This changes the refractive index as well as the optical path difference in the FP cavity system which in turn causes spectrum shift of Fabry-Perot interference. This spectrum shift can be correlated with the corresponding moisture level. This system is illustrated in FIG. 8 as a cascaded nature.

[0085] In an aspect, Fan-in / Fan-out devices may be used to multiplex / demultiplex several signals accurately. In this approach, even multiple parameter sensing cables such as temperature, strain, gas, humidity, etc. can be multiplexed together, transmitted with one multicore fiber, and on the other end, can be demultiplexed for every parameter. This process will reduce the system complexity by minimizing the number of fiber optic cables required for transmitting every sensing parameter. This process is displayed in FIG. 9. It will be understood that detecting four parameters is shown in FIG. 9, this is non-limiting and more or less than four parameters may be detected.

[0086] This disclosure is further illustrated by the following examples, which are nonlimiting.EXAMPLESResults of pH sensors in buffers of varying pH

[0087] The optical fiber pH sensor was tested by Optical Frequency Domain Reflectometry (OFDR). The sensor was fabricated according to tire steps shown in Table 1. Table 1No. Description Duration1 SMF (Polyimide coating) Remove the coating by fire.Use acetic acid (pH 3.5) and 3-(trimethoxysilyl)propyl 2 Modify the fiber surfacemethacrylate. Treat for 2 hours at room temperature.3 Wash with deionized water. Use acetic acid washPrepare the hydrogel upon light4 The hydrogel is treated under UV light for 20 hours.exposure.5 Put the fiber into the prepared30 minuteshydrogel.Remove from hydrogel and allow it to6 Use acetic acid wash and allow it to dry for 48 hours.dry.

[0088] Before the test, the pH meter was calibrated with a pH 8.0 buffer. The results of the calibration show that the measurement error was 0.01, which is within the allowable error range.Performance Evaluation of Dual -Parameter pH and T emperature Sensor(UML 2024-007-02)

[0089] The pH value was adjusted with HC1 and NaOH solution using Di water. The sensor demonstrated minimal changes in performance after three autoclaving cycles, maintaining excellent linearity and resolution. Sensitivities were 1,94 GHz / pH before and 1.91 GHz / pH after autoclaving for pH, and 1.45 GHz / °C for temperature. Resolutions were approximately 0.01 pH and 0.01 °C, confirming that autoclaving had negligible impact on functionality while preserving measurement accuracy.

[0090] OFDR was utilized to validate the sensitivity of the pH and temperature dual¬ parameter sensor. The experimental setup is illustrated in FIG. 10, showing the optical fiber (1001) having a temperature sensing region (1002) and a pH sensing region (1003), and coupled to an OFDR (1004). The sensing portions of the fiber are situated in an enclosure (1005) including a heater (1006) and a pH and temperature meter (1007). The sensors underwent processing using an existing autoclave machine. To protect the sensors during tire autoclaving process, they were enclosed in self-sealing sterilization pouches. Measurements were taken before and after autoclave.

[0091] Under controlled conditions with the solution temperature maintained at 22°C, tests were conducted across a pH range of 4 to 11. Linear fit showed that pH sensor demonstrated sensitivities of 1.94 GHz / pH before autoclaving with an adjusted R-squared of 0.996 and 1.91 GHz / pH after with an adjusted R-squared of 0.997. In separate experiments, the temperature sensor was tested from 25-45 °C at fixed pH values of 4, 7, and 11, where it showed a sensitivity of 1.45 GHz / °C with an adjusted R-squared of 0.994. Specifically, a spectral shift (GHz) was observed versus pH in the range of 4 to 11. The pH sensing region demonstrated sensitivity: Before autoclave: 1.94 GHz / pH, R-squared: 0.996, Resolution: 0.01 pH; After autoclave: 1.91 GHz / pH, R-squared: 0.997, Resolution: 0.01 pH. A spectral shift (GHz) was also observed versus temperature. The temperature sensitivity: 1.45 GHz / °C, R-squared: 0.995, Resolution: 0.01 °C.

[0092] It was observed that the autoclave process had minimal impact on the performance of both the pH and temperature dual sensors. According to tire test sensitivities of 1.94 GHz / pH and 1.45 GHz / °C

[0019] , Based on the resolution of OFDR (0.1 GHz = 0.015 GHz),the calculated resolutions for the pH and temperature sensor are approximately 0.01 pH and 0.01 °C.Accuracy and Precision Comparison

[0093] To demonstrate the effective functioning of the optical fiber sensor during(UML 2024-007-02)bioprocesses, CHO cells were cultured in Immediate Advantage 73811C (AMBIC BASAL Media 1.1) by Millipore Sigma. A 150 mL cell culture volume was maintained in a 500 mL shake flask at a reaction temperature of 37°C. An Incubator with shaker speed of 125rpm was used to maintain the temperature and provide consistent stirring throughout the process. A gradual increase in CO2levels was implemented to induce pH changes in the cell culture, allowing for a more robust comparison. pH measurements were taken every half hour from the start of the experiment, for a total of 8 readings. These readings were obtained using both a commercially available analyzer and the optical fiber sensor of the present disclosure. The signals from the optical fiber sensor were recorded using OFDR, and pH values were calculated based on the linear equation fitted from the results above.

[0094] The accuracy of the present pH sensor was evaluated by comparing its measurements to those from the commercial analyzer, a well-established method in bioprocessing. Based on eight tests, the comparison plot (FIG. 11) show s that the readings from the present sensor and the commercial analyzer readings are very close to each other. Most of the differences between the present sensor and commercial analyzer readings are w ithin the 95% confidence interval, demonstrating a high degree of consistency between the two methods.

[0095] Notably, the pH resolution of the sensor of the present disclosure can achieve 0.1. The mean error across all measurements was a minimal 0.0039, with a standard deviation of 0.0344, emphasizing the precision of the present sensor in practical scenarios. All of these results show that the present pH sensor works very accurately and reliably making it a valuable tool for bioprocessing applications that require precise pH monitoring.Moisture sensing

[0096] Moisture sensing testing was conducted with carbon black-coated fiber optic sensor. As an interrogation system, OFDR was used. The schematic for the experimental setup is displayed in FIG, 12.

[0097] The experiment was performed by putting the sensing region in water and collecting the spectral shift response for water while keeping the air response as a reference. To ensure repeatability, the test was repeated three times on the same day, and also for stability, we collected the datasets for six days. For every circumstance, a similar response was achieved, which ensures the functional capability of the reported sensor. The responses are displayed in FIG. 13A and 13B, where the spike in the response of the coated region is caused by a non-uniform coating.

[0098] The experiment was then conducted while putting the sensing region on the soil.(UML 2024-007-02)First the sensor response for dry soil was collected and considered as a reference. The moisture level of the soil was then gradually increased adding water at 10%, 20%, 30%, and 40%. For every moisture level, collected the responses and after signal processing the responses are depicted in FIG. 14. The non-monotonic sensor response with increasing soil moisture is caused by capillary suction effects in partially saturated soil. At low to moderate moisture levels, small amounts of water form capillary bridges between soil particles, increasing soil stiffness and mechanical stress on the coated fiber, which produces a larger spectral shift. As moisture increases further, the soil becomes softer and capillary forces decrease, reducing the strain transferred to the fiber. Therefore, the sensor response reflects moisture-dependent changes in soil mechanical behavior rather than direct water absorption by the PDMS-carbon black coating,

[0099] A moisture sensor having two sensing regions, each coated with carbon black, was also fabricated. The test set-up was updated to reduce the environmental temperature effect using a closed temperature chamber. For moisture data collection, the soil with different moisture levels (10%, 20% and 30%) was put inside the temperature chamber, and the two sensing regions were embedded into the soil. To keep tire surrounding temperature fixed, the temperature chamber was at 25°C while collecting datasets. For repeatability performance analysis, the datasets were recorded for this sensor three times under the same experimental condition. The experimental results an exemplary test are displayed in FIG. 15. The peaks correspond to the sensing regions on the fiber.

[0100] From the response shown in FIG. 1, it can be seen that for both sensing regions, a similar response pattern was achieved for all three tests which express the repeatability characteristics of the presented sensor. A proportional relation between the spectral shift and moisture level was achieved. The more the moisture level, the higher the spectral shift. For the non-uniform coating, there are some spikes in the sensing region.

[0101] An additional sensor was fabricated having two sensor regions. To ensure the sensor’s repeatability performance, the same three moisture levels (10%, 20% 30%) as before were tested first and then the moisture levels were increased to 40% to record the spectral shift. Exemplary results for 10% moisture level are shown in FIG, 16.

[0102] As shown by the results in FIG. 16, the sensor exhibits repeatable performance for all moisture levels. Increased moisture level at 40% was observed to hold the same proportional relation between the moisture level and spectral shift.

[0103] Another cascaded fiber optic sensor was fabricated with a temperature and moisture sensor. The moisture sensor was fabricated as the same approach as sensors using carbon black and the temperature sensor was protected by using tubing.(UML 2024-007-02)

[0104] A heating plate was used to change the temperature range and the temperature sensing portion of the cascaded sensor was put on the heating plate. A moisture sensing region was embedded in the soil and the moisture level of the soil was varied. To reduce the environmental temperature effect, both sensing sections were put inside a closed chamber.

[0105] At different temperature and moisture levels, datasets were collected to record the sensor response, The first sensor response was recorded at room temperature 25°C and dry soil. Then both temperatures (at 45°C and 55°C) and moisture levels (10% and 20%) were varied, and corresponding responses were recorded. To validate the unique response of each sensing region, at 55°C, two moisture levels (20% and 30%) responses were recorded. Results are shown in FIG. 17.

[0106] From FIG. 17, it can be observed that at dry soil (i.e., 0% moisture level) and without any heat, the response is near zero for both sensing sections. While turning on the heating plate and keeping the temperature at 25°C, only the temperature regions’ spectral shift changed, and no change occurred for the moisture sensor response because the moisture level was not changed. The spectral shift of the temperature sensing region goes down with temperature increment and at the moisture sensing region, the spectral shift goes up with moisture level increment. The fluctuations at the datasets of the same 55°C occurred due to the internal temperature as the heating plate was on for a long time. To increase moisture sensitivity, a hygroscopic material can be added in the coating and can be tested in a closed humidity chamber.

[0107] For DO sensing, the sensor utilized fluorescence quenching technology with a robust optical composite thin film. A thin film dissolved oxygen optical sensor was fabricated by encapsulating the phosphorescent dye erythrosin B in a sol-gel / fluoropolymer composite matrix. Strong phosphorescence, which was efficiently quenched by dissolved oxygen, was observed, achieving a sensitivity of 0.01 mg / L across a range of 0-42 mg / L. The sensor exhibits strong phosphorescence, quenched in the presence of dissolved oxygen in water. The degree of quenching is directly proportional to the DO concentration, enabling accurate real-time measurements. The sensor operates within a wavelength range of 680 nm.

[0108] The dissolved oxygen (DO) sensor coating was formulated using ETEOS (ethyltriethoxysilane, 4.328 mL) and GPTMS ( 3 -glycidoxy propyltrimethoxy silane, 4.45 mL) as sol-gel precursors to form an organic-inorganic hybrid netw ork; Erythrosin B (4 mL) as the DO- responsive fluorescent dye; and a catalytic system of 1 -methylimidazole (4 mL) and 0.1 M HC1 (0.1 mL) to promote silane hydrolysis-condensation and epoxy ring opening, thereby tuning cross-link density and film-formation kinetics to yield a stable, sensitive coating, shown as in(UML 2024-007-02)Table 2.Table 3Material Function Quantity ETEOS (ethyltriethoxysilane) Sol-gel precursor 4.328 ml GPTMSSol-gel precursor 4.45 ml (3-glycidoxypropyltrimethoxy silane)Erythrosin B DO-sensitive fluorescent dye 4.0 ml 1-methylimidazole Catalyst 4.0 ml0.1 M HCl Catalyst 0.1 ml

[0109] Experimental observations indicate that no sol-gel network was formed on day 1; by day 2, gelation and film formation were observed, producing uniform, adherent coatings. Beyond day 2 (e.g., by day 3), the mixture becomes over-gelled and solid-like, substantially reducing spreadability and rendering it unsuitable for coating.

[0110] A calibration of the dissolved oxygen (DO) sensor was conducted in standard solutions of 0%, 20%, 40%, 60%, and 80% under benchtop conditions. Fluorescence intensities were normalized to the anoxic reference (Io), and the resulting Stern-Volmer plot (lo / l versus [DO]) exhibited a linear response over 0-80 % with a sensitivity (slope) of 0.0545 (Io / I)·(%)⁻¹ and a coefficient of determination R2= 0.9736, indicating good linearity and robust analytical performance across the tested range. The monotonic increase of Io / I with [DO] is consistent with dynamic (collisional) quenching of Erythrosin B, confirming that the dye retains its oxygen responsiveness after incorporation into the sol-gel matrix and within the assembled coating.

[0111] Taken together, these results support the suitability of the current coating formulation for quantitative DO measurement in media relevant to cell culture. The observed linear dynamic range simplifies calibration and real-time demodulation, while the measured sensitivity suggests adequate capability to resolve small concentration changes around typical operating setpoints. Erythrosin B was validated as an exemplary effective DO reporter for the optical fiber sensor and provides a basis for subsequent integration and in situ testing.

[0112] The LPFG-based refractive index sensor was functionalized with a multi-layer composite of graphene oxide (GO), gold nanoparti cles (AuNPs), polyethylene glycol (PEG), and glucose oxidase (GOx). GO provides a high-surface-area scaffold for enzyme immobilization and enhances stability. AuNPs, with their localized surface plasmon resonance (LSPR) peak at -520-530 nm, amplify the evanescent field interaction, improving sensitivity’. Upon glucose oxidation by GOx, the resulting refractive index changes lead to a measurable shift in the LPFG resonance. A schematic illustration of an exemplary glucose sensor structure is shown in FIG.18.(UML 2024-007-02)

[0113] Using the same design principle, a lactate sensor was developed by replacing GOx with lactate oxidase (LOx) and AuNPs with silver nanoparticles (AgNPs), which exhibit stronger LSPR at shorter wavelengths (-400-450 nm). This configuration enables sensitive, label-free detection of lactate through LSPR-enhanced refractive index modulation.Table 4Material Role in SensorGraphene Oxide (GO) Provides high surface area for enzyme immobilization and enhances composite stability.Gold Nanoparticles (AuNPs) Enhance local electric field via LSPR (peak ~650 nm):improve refractive index sensitivity.Glucose Oxidase (GOx) Catalyzes glucose gluconic acid + H2O2; changes local RI, resulting inLPFG wavelength shift.Silver Nanoparticles (AgNPs) Strong LSPR (peak -560 nm); amplify local field and increase sensitivity.Poly ethylene Glycol (PEG) Maintains a bioconipatible, stable surface for enzyme activity. Lactate Oxidase (LOx) Catalyzes lactate pyruvate + H2O2; alters local RI,triggering LPFG resonance wavelength shift.

[0114] A glucose sensor was fabricated using the method described above and tested accordingly. To enhance the evanescent field, the optical fiber was chemically etched to reduce its diameter and increase surface roughness. Phosphate-buffered saline (PBS) was used as the base solution to adjust glucose concentrations, ensuring consistent light transmission during testing. Tlie glucose sensor demonstrated effective quantification of glucose concentrations in the range of 2-10 mM, with a sensitivity of 0.1384 (I / Io) / mM. The transmission spectra at 300nm-1100 nm and 653nm-660 nm are shown in FIG. 19 A and 19B.

[0115] This disclosure further encompasses tlie following aspects.

[0116] Aspect 1: A sensor comprising: an optical waveguide having at least one sensing region formed on a portion thereof; a light source configured to provide an optical signal to the optical waveguide; and a detector configured to receive a signal from the optical waveguide; wherein the at least one sensing region is capable of determining pH, temperature, dissolved oxygen concentration, glucose concentration, lactate concentration, NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS), or moisture level.

[0117] Aspect 2: The sensor of aspect 1, wherein the optical waveguide comprises a single-mode fiber, a multimode fiber, coreless termination fiber, hollow' core photonic crystal fiber or a plastic optical fiber.

[0118] Aspect 3: The sensor of aspect 1 or aspect 2, wherein the optical waveguide comprises a first sensing region, a second sensing region, optionally a third sensing region, optionally a fourth sensing region, optionally a fifth sensing region, optionally a sixth sensing region, optionally a seventh sensing region, and optionally an eighth sensing region.(UML 2024-007-02)

[0119] Aspect 4: The sensor of aspect 3, wherein tlie first sensing region is capable of determining pH and the second sensing region is capable of determining temperature.

[0120] Aspect 5: The sensor of aspect 3 or 4, wherein the first sensing region compri ses a pH-sensitive material comprising a hydrogel coating on a portion of a surface of the optical waveguide, preferably wherein the hydrogel is a pH responsive hydrogel and exhibits a change in swelling at varying pH levels.

[0121] Aspect 6: The sensor of aspect 5, wherein the pH-sensitive material comprises a hydrogel and a pH sensitive fluorescent probe, preferably 8-hydroxypyrene-l,3,6-trisulfonic acid.

[0122] Aspect 7: The sensor of any of aspects 1 to 6, wherein the at least one sensing region comprises a Fiber Bragg Grating, a Fabry-Perot interferometer, LPG, a tapered region, or a combination thereof.

[0123] Aspect 8: The sensor of any of aspects 1 to 7, wherein the detector comprises a Raman scattering detector, Fiber Bragg Grating demodulator, optical frequency domain reflector, optical spectrum analyzer, or a spectrometer.

[0124] Aspect 9: lire sensor of any of aspects 1 to 7, wherein the light source and the detector are housed in a single unit.

[0125] Aspect 10: The sensor of any of aspects 1 to 9, wherein the optical waveguide comprises a first sensing region, a second sensing region, optionally a third sensing region, and optionally a fourth sensing region, wherein each of the first, second, third, and fourth sensing regions are independently capable of determining pH, temperature, dissolved oxygen concentration, glucose concentration, or lactate concentration.

[0126] Aspect 11: Tire sensor of any of aspects 1 to 10, w herein the at least one sensing region is capable of determining moisture level.

[0127] Aspect 12: The sensor of aspect 11, wherein the at least one sensing region capable of determining moisture level comprises a moisture sensitive coating disposed on a surface of the optical waveguide, preferably wherein tire coating comprises carbon black.

[0128] Aspect 13: The sensor of any of aspects 11 or 12, further comprising a second sensing region capable of determining temperature.

[0129] Aspect 14: Tire sensor of any of aspects 1 to 10, w herein the at least one sensing region is capable of determining dissolved oxygen concentration.

[0130] Aspect 15: The sensor of aspect 14, wherein the at least one sensing region capable of determining dissolved oxygen concentration comprises a fluorescent dissolved oxygen reporter, preferably Erythrosin B.(UML 2024-007-02)

[0131] Aspect 16: The sensor of any of aspects 1 to 10, wherein the at least one sensing region is capable of determining glucose concentration.

[0132] Aspect 17: The sensor of aspect 16, wherein the at least one sensing region capable of determining glucose concentration comprises graphene oxide, gold nanoparticles, polyethylene glycol, and glucose oxidase.

[0133] Aspect 18: The sensor of any of aspects 1 to 10, wherein the at least one sensing region is capable of determining lactate concentration.

[0134] Aspect 19: The sensor of aspect 18, wherein the at least one sensing region capable of determining lactate concentration comprises graphene oxide, silver nanoparticles, polyethylene glycol, and lactate oxidase.

[0135] Aspect 20: A bioreactor comprising the sensor of any of aspects 1 to 19, optionally wherein the bioreactor is a stirred tank bioreactor, milliliter-scale shake flask, single-use bioreactor bag, or automated bioreactor system.

[0136] Aspect 21: The bioreactor of aspect 20, wherein the optical waveguide is in a spiral wound configuration on an internal surface of the single-use bioreactor; or affixed to an internal surface of the single-use bioreactor in a linear configuration.

[0137] Aspect 22: A method for monitoring moisture level, the method comprising: disposing an optical sensor according to any of aspects 1 to 19, preferably according to any of aspects 11 to 19, in an area to be monitored; transmitting optical signals through the optical sensor from a light source to and from the at least one sensing region, wherein reflectance from the at least one sensing region varies with the moisture content of the sensing region; and measuring the returned light reflected by the sensing region.

[0138] Aspect 23: The method of aspect 22, further comprising detecting changes in the returned light reflected by the sensing region corresponding to a change in moisture level.

[0139] Aspect 24: The method of aspect 22 or 23, wherein moisture is measured continuously, in real time, or both.

[0140] Aspect 25: A method for monitoring a bioprocess in a bioreactor, the method compri sing: disposing an optical sensor according to any of aspects 1 to 19, preferably according to aspect 10, in a bioreactor; transmitting optical signals through the optical sensor from a light source to and from the at least one sensing region; and measuring the light from the at least one sensing region; wherein the light from the at least one sensing region corresponds to at least one of pH, temperature, di ssolved oxygen concentration, glucose concentration, or lactate concentration in the bioreactor.

[0141] Aspect 26: The method of aspect 25, wherein the bioprocess is monitored(UML 2024-007-02)continuously, in real time, or both.

[0142] Aspect 27: The method of any of aspects 25 to 26, wherein the bioreactor is a bioreactor, milliliter-scale shake flask, single-use bioreactor bag, or automated bioreactor system.

[0143] The compositions, methods, and articles can alternatively comprise, consist of, or consist essentially of, any appropriate materials, steps, or components herein disclosed. The compositions, methods, and articles can additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any materials (or species), steps, or components, that are otherwise not necessary to the achievement of the function or objectives of the compositions, methods, and articles,

[0144] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. “Combinations” is inclusive of blends, mixtures, alloys, reaction products, and the like, lire terns “first,” “second,” and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms “a” and “an” and “the” do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. “Or” means “and / or” unless clearly stated otherwise. Reference throughout the specification to “an aspect” means that a particular element described in connection with the aspect is included in at least one aspect described herein, and may or may not be present in other aspects. The term “combination thereof’ as used herein includes one or more of the listed elements, and is open, allowing the presence of one or more like elements not named. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various aspects.

[0145] Unless specified to the contrary herein, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears.

[0146] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference.

[0147] Compounds are described using standard nomenclature. For example, any position not substituted by any indicated group is understood to have its valency filled by a bond(UML 2024-007-02)as indicated, or a hydrogen atom. A dash that is not between two letters or symbols is used to indicate a point of attachment for a substituent. For example, -CHO is attached through carbon of the carbonyl group.

[0148] While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.

Claims

1. (UML 2024-007-02)CLAIMS1. A sensor comprising:an optical waveguide having at least one sensing region formed on a portion thereof; a light source configured to provide an optical signal to the optical waveguide; and a detector configured to receive a signal from the optical waveguide;wherein the at least one sensing region is capable of determining pH, temperature, dissolved oxygen concentration, glucose concentration, lactate concentration, NAD+ / NADH, pressure, flow rate, reactive oxygen species (ROS), or moisture level.

2. Hie sensor of claim 1, wherein the optical waveguide comprises a single-mode fiber, a multimode fiber, coreless termination fiber, hollow core photonic cry stal fiber or a plastic optical fiber.

3. Tire sensor of claim 1, wherein the optical waveguide comprises a first sensing region, a second sensing region, optionally a third sensing region, optionally a fourth sensing region, optionally a fifth sensing region, optionally a sixth sensing region, optionally a seventh sensing region, and optionally an eighth sensing region.

4. The sensor of claim 3, wherein the first sensing region is capable of determining pH and the second sensing region is capable of determining temperature.

5. Tire sensor of claim 3, wherein the first sensing region comprises a pH-sensitive material comprising a hydrogel coating on a portion of a surface of the optical waveguide, preferably wherein the hydrogel is a pH responsive hydrogel and exhibits a change in swelling at varying pH levels.

6. The sensor of claim 5, wherein the pH-sensitive material comprises a hydrogel and a pH sensitive fluorescent probe, preferably 8-hydroxypyrene-l,3,6-trisulfonic acid.

7. Hie sensor of claim 1, wherein the at least one sensing region comprises a Fiber Bragg Grating, a Fabry-Perot interferometer, LPG, a tapered region, or a combination thereof.

8. The sensor of claim 1, wherein the detector comprises a Raman scattering detector, Fiber Bragg Grating demodulator, optical frequency domain reflector, optical spectrum analyzer, or a(UML 2024-007-02)spectrometer.

9. The sensor of claim 1, wherein the light source and the detector are housed in a single unit.

10. The sensor of claim 1, wherein the optical waveguide comprises a first sensing region, a second sensing region, optionally a third sensing region, and optionally a fourth sensing region, wherein each of the first, second, third, and fourth sensing regions are independently capable of determining pH, temperature, dissolved oxygen concentration, glucose concentration, or lactate concentration.

11. The sensor of claim 1, wherein the at least one sensing region is capable of determining moisture level.

12. Tire sensor of claim 11, wherein the at least one sensing region capable of determining moisture level comprises a moisture sensitive coating disposed on a surface of the optical waveguide, preferably wherein the coating comprises carbon black.

13. The sensor of claim 11, further comprising a second sensing region capable of determining temperature.

14. Tire sensor of claim 1, wherein the at least one sensing region is capable of determining dissolved oxygen concentration.

15. The sensor of claim 14, wherein the at least one sensing region capable of determining dissolved oxygen concentration comprises a fluorescent dissolved oxygen reporter, preferably Erythrosin B.

16. Tire sensor of claim 1, wherein the at least one sensing region is capable of determining glucose concentration.

17. The sensor of claim 16, wherein the at least one sensing region capable of determining glucose concentration comprises graphene oxide, gold nanoparticles, polyethylene glycol, and glucose oxidase.(UML 2024-007-02)18. The sensor of claim 1, wherein the at least one sensing region is capable of determining lactate concentration,19. The sensor of claim 18, wherein the at least one sensing region capable of determining lactate concentration comprises graphene oxide, silver nanoparticles, polyethylene glycol, and lactate oxidase.

20. A bioreactor comprising the sensor of claim 1, optionally wherein the bioreactor is a stirred tank bioreactor, milliliter-scale shake flask, single-use bioreactor bag, or automated bioreactor system.

21. The bioreactor of claim 20, wherein tire optical w aveguide isin a spiral wound configuration on an internal surface of the single-use bioreactor; or affixed to an internal surface of the single-use bioreactor in a linear configuration.

22. A method for monitoring moisture level, the method comprising:disposing an optical sensor according to claim 1 in an area to be monitored; transmitting optical signals through the optical sensor from a light source to and from the at least one sensing region, wherein reflectance from the at least one sensing region varies with the moisture content of the sensing region; andmeasuring the returned light reflected by the sensing region.

23. The method of claim 22, further comprising detecting changes in the returned light reflected by the sensing region corresponding to a change in moisture level.

24. The method of claim 22, wherein moisture is measured continuously, in real time, or both.

25. A method for monitoring a bioprocess in a bioreactor, the method comprising:disposing an optical sensor according to claim 1 in a bioreactor;transmitting optical signals through the optical sensor from a light source to and from the at least one sensing region; andmeasuring the light from the at least one sensing region;(UML 2024-007-02)wherein the light from the at least one sensing region corresponds to at least one of pH, temperature, dissolved oxygen concentration, glucose concentration, or lactate concentration in the bioreactor.

26. The method of claim 25, wherein the bioprocess is monitored continuously, in real time, or both.

27. Hie method of any of claims 25, wherein the bioreactor is a bioreactor, milliliter-scale shake flask, single-use bioreactor bag, or automated bioreactor system.

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