Pear-shaped optical fiber LSPR and preparation method and blood coagulation process monitoring application thereof

Abstract

The invention relates to the technical field of biology, in particular to a pear-shaped optical fiber LSPR (Localized Surface Plasmon Resonance) as well as a preparation method and blood coagulation process monitoring application thereof. The pear-shaped optical fiber LSPR is formed by processing a multimode optical fiber, the peak value of the pear-shaped optical fiber LSPR is less than 3 a.u., the pear-shaped optical fiber LSPR comprises a pear-shaped structure and an optical fiber structure, the optical fiber structure is connected with the pear-shaped structure, and the maximum outer diameter of the pear-shaped structure is 0.4 mm-0. 8 mm. The optical fiber LSPR can rapidly obtain the weak change of the refractive index in the human serum coagulation process, and a PT result can be obtained within 1 min. The monitoring method has the advantages that the device is portable, the operation is simple, the analysis is rapid, the household PT monitoring is expected to be realized, and a potential solution is provided for the household self-management of the anticoagulant medicine of the atrial fibrillation patient.

Description

Technical Field

[0001] The invention relates to the field of biotechnology, and in particular to a pear-shaped optical fiber LSPR and a preparation method thereof and a coagulation process monitoring application thereof. Background Art

[0002] With the aging population, the prevalence of atrial fibrillation in my country continues to rise, with the number of patients reaching 20 million. Warfarin is the most widely used and oldest anticoagulant drug in the world and is widely used in the treatment of patients with atrial fibrillation. Due to the huge individual differences in its dose-effect relationship, the use of warfarin in patients with atrial fibrillation requires frequent self-management to prevent overdose or underdose, which is the key to reducing the risk of stroke in patients with atrial fibrillation.

[0003] International normalized ratio (INR) monitoring is the main means of self-management of warfarin dosage. For patients with atrial fibrillation, warfarin requires lifelong high-frequency INR testing. In my country, patients' INR monitoring relies on the testing departments of large hospitals, which greatly reduces the compliance, effectiveness and safety of patients' warfarin treatment. Point-of-care test (POCT) is a new type of rapid, accurate and easy-to-operate technology that only needs to analyze the patient's coagulation process to obtain INR results. The US FDA has approved the use of POCT technology in INR monitoring. However, in China, where there are a large number of people using warfarin, the number of people using POCT technology to conduct INR home monitoring is almost zero. In recent years, Chinese experts have reached an expert consensus on POCT home monitoring of INR. It can be seen that the development of POCT technology for INR monitoring is imminent and imperative.

[0004] At present, there are some commercial INR monitors on the market, such as Roche Kanggu complete coagulation tester, Micropoint Q3 coagulation tester and Kang Liming's Coagulation detectors, and some clinical studies have found that the test results of commercial INR monitors are highly consistent with laboratory results, which can guide patients' warfarin dosage. It can be seen that the development of home monitoring INR instruments has the potential to serve as an important supplement to laboratory INR monitoring, which greatly improves the convenience of patient INR monitoring. However, commercial INR monitors on the market are expensive and cannot meet the home monitoring needs of ordinary atrial fibrillation patients. Summary of the invention

[0005] The researchers of the present invention found that during the coagulation process of blood, its refractive index will change significantly. This change is its inherent property and is less affected by external environmental interference such as vibration, processing size or ambient light. It can be used to develop INR home monitoring sensors.

[0006] The localized surface plasmon resonance (LSPR) of optical fiber is a real-time, label-free refractive index analysis technology. Optical fiber LSPR has the advantages of small size, low price, and portability, and is an emerging POCT technology. Therefore, optical fiber LSPR sensors have the potential to develop home monitoring sensors for INR.

[0007] However, the optical fiber LSPR sensors currently available in the market have low refractive index sensitivity and cannot be actually applied to the development of INR monitors to achieve real-time monitoring of coagulation.

[0008] At present, the sensitivity of bare optical fiber can hardly exceed 30 (au) / RIU. On this basis, even after modification with nanometal materials, the improvement in sensitivity is limited. Excessive modification with nanometal materials will cause confusion in the spectrum due to the limitation of the accuracy of the spectrometer, and ultimately lead to inaccurate monitoring results. This puts higher requirements on the accuracy of the spectrometer and increases the cost of monitoring.

[0009] In addition, currently, whether it is changing the shape, optimizing the modification of nanometal materials, or combining the two to improve the refractive index sensitivity of fiber LSPR, it is impossible to monitor very weak refractive index changes, resulting in limited applications of fiber LSPR.

[0010] Based on the above-mentioned problem that the refractive index sensitivity is low, resulting in excessively high requirements for monitoring equipment, the present invention proposes a pear-shaped optical fiber LSPR and a preparation method and application thereof, which greatly improves the refractive index sensitivity of the optical fiber sensor by miniaturizing the overall structure of the optical fiber, and further improves the sensitivity by modifying it with nano-metal materials, so as to solve the problem that the refractive index sensitivity of the optical fiber LSPR is insufficient and it is difficult to develop an INR monitor.

[0011] The details are as follows:

[0012] A pear-shaped optical fiber LSPR is formed by processing a multimode optical fiber, has a peak value of less than 3 a.u., contains a pear-shaped structure and an optical fiber structure, the optical fiber structure is connected to the pear-shaped structure, and the maximum outer diameter of the pear-shaped structure is 0.4mm-0.8mm.

[0013] Preferably, the pear-shaped optical fiber LSPR peak is below 1.2 au, and more preferably, the pear-shaped optical fiber LSPR peak is 0.2-1.2 au.

[0014] The "pear-shaped fiber LSPR peak" described in the present invention is to incubate the pear-shaped fiber with the nano-metal material and monitor the changes in its absorption spectrum in real time. The peak of its absorption spectrum is the signal of the sensor, that is, the pear-shaped fiber LSPR peak.

[0015] When the pear-shaped fiber LSPR peak is low, the requirements for the accuracy of the spectrometer are lower, and it can be adapted to more application scenarios. The higher the modification, the greater the refractive sensitivity, and it is more susceptible to interference from the environment and the instrument itself. However, depending on different needs, such as specific scenarios, it can be adapted to high-precision instruments and eliminate environmental interference. In order to pursue higher sensitivity, it can be modified to 3 a.u.

[0016] Furthermore, the pear-shaped structure is composed of a SiO2 core, a SiO2 cladding and a nano-metal material, the SiO2 cladding is wrapped around the outer layer of the SiO2 core, and the nano-metal material is modified on the SiO2 cladding.

[0017] The "modification" mentioned in the present invention refers to that the nano-metal material is uniformly or non-uniformly wrapped on the outer surface of the SiO2 cladding. The interaction of positive and negative functional groups such as electrostatic adsorption can be adopted, or covalent modification and other methods can be selected, as long as the nano-metal material is fixed on the surface of the pear-shaped structure; the purpose of the "modification" is to construct a pear-shaped optical fiber LSPR, and the localized surface plasmon resonance (LSPR) of the pear-shaped optical fiber is realized by the nano-metal material, that is, the signal enhancement is triggered.

[0018] Furthermore, the nanometal material is selected from nanogold or nanosilver;

[0019] The shape of the nanometal material is not limited in the present invention. The nanometal material is used in the LSPR sensor to enhance the excitation of the LSPR, thereby improving the refractive index sensitivity. The optical fiber LSPR principle of the present invention is the same as that of the ordinary LSPR sensor. Preferably, gold nanospheres, gold nanorods, gold nanostars, etc. can be selected. More preferably, the particle size of the gold nanospheres is 13nm-50nm.

[0020] Furthermore, the pear-shaped structure comprises a first straight segment, a first curved segment and a second straight segment, two ends of the first curved segment are respectively connected to the first straight segment and the second straight segment, and an angle exists between the first straight segment or the second straight segment and the first curved segment;

[0021] Or there is an angle between the first straight segment and the second straight segment.

[0022] In some embodiments, there is an angle between the first straight segment or the second straight segment and the first curved segment, and at the same time, there is an angle between the first straight segment and the second straight segment;

[0023] In some embodiments, there is an angle between the first straight segment or the second straight segment and the first curved segment, and at the same time, there is no angle between the first straight segment and the second straight segment;

[0024] In some embodiments, there is no angle between the first straight segment or the second straight segment and the first curved segment, and at the same time, there is an angle between the first straight segment and the second straight segment.

[0025] The "first straight segment" and "second straight segment" mentioned in the present invention refer to a straight segment or a quasi-straight segment, which is a straight segment visually relative to the curved segment, but may have a slight curve.

[0026] The "maximum outer diameter of the pear-shaped structure" mentioned in the present invention refers to the value of the position with the largest width in the pear-shaped structure, that is, the maximum outer diameter of the first curved segment mentioned above. The outer diameter refers to the diameter including the core and cladding, and the maximum outer diameter refers to the maximum value of the diameter of the entire pear-shaped structure including the core and cladding.

[0027] In some embodiments, the maximum outer diameter of the pear-shaped structure is 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm.

[0028] The pear-shaped optical fiber of the present invention is formed by processing a multimode optical fiber, and the multimode optical fiber comprises a SiO2 core, a cladding layer and a coating layer.

[0029] Pear-shaped optical fiber can change the transmission of light, allowing the light transmitted by the core to enter the cladding, while at the same time converting the light transmitted by the fundamental film into high-order mode transmission, thereby enhancing the energy share of the cladding mode, which is beneficial to the excitation of the optical fiber LSPR.

[0030] Furthermore, the optical fiber structure consists of a SiO2 core, a cladding and a coating layer, the diameter of the core is 50 or 62.5, and the diameter of the cladding is 125 μm.

[0031] The present invention utilizes extremely fine optical fiber (cladding diameter is 125 μm) to control the maximum outer diameter of the pear-shaped structure to 0.3 mm-1 mm, which can greatly improve the refractive index sensitivity. Moreover, since the pear-shaped structure is the detection part of the pear-shaped optical fiber, the miniaturized structure can reduce the amount of samples and related reagents used.

[0032] The present invention adopts common communication optical fiber and has low cost.

[0033] Furthermore, the pear-shaped structure and the inner core of the optical fiber structure are integrally formed.

[0034] Furthermore, the total length of the pear-shaped structure is 2 mm-10 cm, and the total length of the pear-shaped structure is the total length of the first straight segment, the first curved segment and the second straight segment.

[0035] In another aspect, the present invention discloses a sensor comprising the pear-shaped optical fiber LSPR.

[0036] On the other hand, the present invention also discloses a monitoring device, which contains the sensor.

[0037] Furthermore, it includes a light source, a detector, an output device, a pear-shaped optical fiber LSPR, and an optical fiber jumper. The pear-shaped optical fiber LSPR is connected to the light source and one end of the detector respectively through the optical fiber jumper, and the other end of the detector is connected to the output device through the optical fiber jumper to output the monitoring results.

[0038] In actual monitoring, a beam of continuous wavelength light emitted from the light source propagates along the optical fiber jumper to the optical fiber probe. The light undergoes localized surface plasmon resonance at the probe covered with spherical gold nanoparticles, and the wavelength and intensity of the resonance absorption peak change. After the optical signal is processed by the spectrometer, spectral data analysis is performed on the computer.

[0039] Furthermore, the light source is selected from a halogen lamp, an LED lamp, and an incandescent lamp.

[0040] Furthermore, the light energy of the light source is 10mWh-100mWh.

[0041] The present invention is dedicated to realizing a low-cost, portable, fast, and easy-to-operate home monitoring device. A major breakthrough is that monitoring can be achieved using an ordinary light source, which can be a halogen tungsten lamp in laboratory conditions, or an LED lamp or an incandescent lamp in home conditions. A special light source can also be used, or a mobile phone, flashlight, or other daily light source. Multiple light source options greatly enrich the use scenarios of the monitoring device.

[0042] Furthermore, the detector is a spectrometer, and the resolution of the spectrometer is below 10nm, and further the resolution is 0.01nm-2nm.

[0043] The present invention has a lower requirement on the resolution of the spectrometer, which can greatly reduce the instrument cost and increase the universality.

[0044] On the other hand, the present invention discloses a method for preparing the pear-shaped optical fiber LSPR, comprising the following steps:

[0045] (1) Take the optical fiber and remove part of the plastic outer layer;

[0046] (2) bending the portion with the plastic outer layer removed at high temperature into a pear-shaped structure;

[0047] (3) Functionalizing the pear-shaped structure in step (2) above and then modifying the nano-metal particles to form a pear-shaped optical fiber LSPR.

[0048] Preferably, the removal of part of the plastic outer layer may be performed by using wire strippers to strip off 3-10 cm of the plastic coating layer.

[0049] The partial plastic outer layer is the middle part of the pear-shaped optical fiber.

[0050] Preferably, the "high temperature" refers to a temperature that can cause SiO2 to bend.

[0051] In one embodiment, the optical fiber with the plastic outer layer removed can be placed on a butane flame and burned into shape in one step under the action of external force.

[0052] In one embodiment, the functionalization of the present invention is to amino-dye the pear-shaped structure so that the surface of the optical fiber is positively charged, thereby adsorbing negatively charged nano-metal particles to form a pear-shaped optical fiber LSPR.

[0053] On the other hand, the present invention discloses a PT monitoring method of the monitoring device, comprising the following steps:

[0054] (1) Save the reference spectrum;

[0055] (2) taking a sample and immersing the pear-shaped structure in the sample;

[0056] (3) After the spectrum stabilizes, the prothrombin reagent is quickly added and data is collected in real time.

[0057] The entire collection time of the present invention does not exceed 1 minute;

[0058] In some embodiments, the spectrometer parameters are set so that the data collection frequency is 10 ms / time, and step (2) can reach stability within 10 seconds, and collecting data for 1 minute is completely sufficient;

[0059] Preferably, the sample is serum.

[0060] On the other hand, the present invention also discloses that the pear-shaped optical fiber LSPR, the sensor or the monitoring device is used for monitoring the coagulation process.

[0061] On the other hand, the present invention also discloses the application of the pear-shaped optical fiber LSPR, the sensor or the monitoring device in atrial fibrillation monitoring.

[0062] The term "functionalization" refers to modifying the surface of optical fiber with functional groups by physical and / or chemical means. The "functional groups" refer to atoms or groups of atoms that determine the chemical properties of organic compounds. They play a key role in organic chemical reactions and determine the properties of organic matter. Common functional groups include amino (-NH2), hydroxyl (-OH), carboxyl (-COOH), ether bond (RO-R'), aldehyde (-CHO), carbonyl (C=O), etc.

[0063] The terms "subject" and "patient" are used interchangeably and refer to mammals in need of treatment, e.g., companion animals (e.g., dogs, cats, etc.), farm animals (e.g., cattle, pigs, horses, sheep, goats, etc.), and laboratory animals (e.g., rats, mice, guinea pigs, etc.). Typically, the subject is a human in need of treatment. In certain embodiments, the term "subject" refers to a human in need of treatment for a disease. In certain embodiments, the term "subject" refers to a human in need of treatment for atrial fibrillation who is taking warfarin.

[0064] Beneficial effects:

[0065] (1) The pear-shaped optical fiber LSPR of the present invention realizes monitoring with extremely high refractive index sensitivity, and can also realize stable monitoring of samples such as blood coagulation whose refractive index changes are very small.

[0066] (2) The present invention can realize fingertip blood monitoring at home, and each monitoring requires only 2 μL of sample at least. Reducing the amount of sample can greatly facilitate sampling by the subject and reduce the pain of the subject.

[0067] (3) The present invention can quickly obtain the results of PT monitoring within 1 minute, and INR can be obtained through mathematical conversion, making home INR monitoring convenient and fast.

[0068] (4) The pear-shaped fiber LSPR of the present invention has an ultra-high sensitivity, which makes it more tolerant to equipment, reduces the requirements for light sources and spectrometers, and enhances anti-interference capabilities, which can not only reduce costs but also adapt to a variety of application scenarios. (5) The pear-shaped fiber LSPR of the present invention can be reused, does not need to replace the sensor for monitoring, is simple to operate, and further reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 : Actual picture of pear-shaped optical fiber.

[0070] Figure 2 :Experiments related to the maximum outer diameter of the pear-shaped structure. (a) Spectrum of the pear-shaped fiber under different sucrose solutions when the outer diameter of the fiber is 0.6 mm. (b) Linear relationship between the pear-shaped fiber and the refractive index under different outer diameters. (C) Comparison of the refractive index sensitivity of the pear-shaped fiber under different outer diameters.

[0071] Figure 3 :Fiber LSPR real-time monitoring of coagulation process.

[0072] Figure 4 : Comparison of clinical laboratory method and fiber optic sensor method in measuring serum PT values. DETAILED DESCRIPTION

[0073] The following examples are intended to illustrate the above invention and should not be construed as narrowing its scope. Those skilled in the art will readily appreciate that the embodiments propose many other ways that can implement the present invention. It should be understood that while remaining within the scope of the present invention, many changes and modifications can be made.

[0074] The detection device in the embodiment is as follows: the pear-shaped optical fiber LSPR / pear-shaped optical fiber is respectively connected to one end of the light source (THORLABSSLS201 / M, light energy is 10mWh-100mWh) and the spectrometer (AvantesAvaSpac-ULS2048), and the other end of the spectrometer is connected to the output device (computer) to output the monitoring results in real time.

[0075] In other implementations, the light source may be an incandescent lamp, an LED lamp, etc.

[0076] In some embodiments, other spectrometers with a resolution of 0.01 nm, 0.1 nm, 0.15 nm, 0.2 nm, 1 nm, 2 nm, 5 nm, 10 nm can be selected.

[0077] Example 1 Preparation and Optimization of Pear-Shaped Fiber

[0078] a. Preparation

[0079] (1) Take the optical fiber and remove part of the plastic outer layer; select a 125μm or 600μm cladding multimode optical fiber and use a wire stripper to strip off 2mm-10cm of the plastic coating.

[0080] (2) bending the portion from which the plastic outer layer is removed into a pear-shaped structure at high temperature; specifically, placing the portion from which the plastic outer layer is removed on a butane flame and burning it into a pear-shaped structure at one time under the action of an external force.

[0081] The maximum outer diameters of the fired pear-shaped structures are different pear-shaped optical fibers of 26mm, 1.1mm, 1.0mm, 0.9mm, 0.8mm, 0.7mm, 0.6mm, 0.5mm, and 0.4mm.

[0082] The actual picture of the pear-shaped optical fiber is as follows Figure 1 shown.

[0083] b. Refractive index sensitivity test

[0084] The pear-shaped optical fiber was placed in sucrose solutions with different refractive indices, the optical fiber absorption spectrum was recorded, and the refractive index sensitivity was calculated. The results are shown in Table 1 and Figure 2 As shown:

[0085] Table 1 Refractive index sensitivity of the maximum outer diameter of different pear-shaped structures

[0086]

[0087] It can be seen that the sensitivity of the cladding at 125μm is higher than that at 600μm, and 600μm cannot complete the preparation of 0.4-1.1mm pear-shaped optical fiber.

[0088] Due to the limitation of the embodiment, the absorption spectrum of 0.6 mm is shown here. It can be seen from the figure that the absorption spectrum of the pear-shaped optical fiber is very smooth and stable, which is suitable for subsequent experiments.

[0089] The refractive index sensitivity can be measured when the maximum outer diameter of the pear-shaped structure is between 1.1 and 0.4 mm. The signal can be further amplified by modifying it with metal nanomaterials.

[0090] The maximum outer diameter of the pear-shaped structure is between 0.4-0.8mm. The refractive index sensitivity of the pear-shaped optical fiber is relatively high, and the smaller the maximum outer diameter of the pear-shaped structure, the higher the refractive index sensitivity. When it is less than 0.5mm, its sensitivity can detect tiny refractive index changes, such as the coagulation process.

[0091] Moreover, the maximum outer diameter of the pear-shaped structure directly determines the amount of sample to be monitored, so an outer diameter that is too large will not only reduce the refractive index sensitivity, but also lead to an increase in the amount of sample and reagents used, thereby increasing costs.

[0092] Example 2 Preparation of pear-shaped optical fiber LSPR

[0093] In Example 1, the pear-shaped optical fibers with a maximum outer diameter of 0.4-0.8 mm in the pear-shaped structure all have high refractive index sensitivity, and the pear-shaped optical fiber with a maximum outer diameter of 0.65 mm in the pear-shaped structure is selected for subsequent experiments.

[0094] After functionalizing the pear-shaped structure, nano-metal particles are adsorbed to form a pear-shaped optical fiber LSPR;

[0095] The details are as follows:

[0096] (1) Functionalization of optical fiber: The pear-shaped structure was soaked in aqua regia for 20 minutes to clean the impurities on its surface, and then the optical fiber was cleaned with ultrapure water, ultrasonicated in ultrapure water for 5 minutes, and dried in a drying machine at 60°C.

[0097] (2) First, take 1.5 ml of 30% H2O2 solution in a small beaker, and then take 3.5 ml of concentrated sulfuric acid in a small beaker to prepare a piranha solution. Then, put the dried optical fiber into the piranha solution and react at 90°C for 30 minutes.

[0098] (3) After the reaction is completed, pour the waste liquid from the piranha into a waste liquid bucket (acid), wash the beaker and the pear-shaped structure with ultrapure water, and ultrasonicate the ultrapure water for 5 minutes.

[0099] (4) After the ultrasonic treatment, dry at 50°C for 10 minutes. Prepare a 5% APTMS solution with 2 ml of glacial acetic acid, 5 ml of ethanol and 350 μl of APTMS, and place the optical fiber in the reaction for 30 minutes. After the reaction, rinse with ultrapure water three times. Then, ultrasonically treat with ultrapure water for 10 minutes, then ultrasonically treat with anhydrous ethanol for 5 minutes, and finally dry at 60°C for use.

[0100] The surface of the pear-shaped structure is amino-treated to make it positively charged. The synthesized nano-gold is wrapped with citrate, which is easy to electrostatically adsorb to the surface of the pear-shaped structure, thus facilitating the preparation of pear-shaped optical fiber LSPR.

[0101] (5) Modification of gold nanoparticles on the surface of pear-shaped structures

[0102] The synthesized 10nM gold nanospheres (particle size of 13nm) were incubated with amino-modified optical fibers. The gold nanospheres were prepared by citric acid reduction method. The detection device monitored the changes in the absorption spectrum in real time. The LSPR peak of the absorption spectrum was selected as the sensor signal. Eight types of fiber optic probes with pear-shaped fiber LSPR peaks of 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, and 2 a.u. were prepared. The pear-shaped fiber LSPR was placed in sucrose solutions with different refractive indices, the fiber absorption spectrum was recorded, and the refractive index sensitivity was calculated.

[0103] In some embodiments, the pear-shaped fiber LSPR peak is selected from 0.2-3 a.u.

[0104] However, in order to achieve low-cost home detection, the spectrometer used in the embodiment of the present invention has low accuracy. Since the refractive index sensitivity of the pear-shaped optical fiber itself is already very high, the spectrometer cannot achieve detection if it is excessively modified.

[0105] The detection device is as follows: a pear-shaped optical fiber LSPR is connected to a light source (THORLABS SLS201 / M, light energy is 10mWh-100mWh) and one end of a spectrometer (Avantes AvaSpac-ULS2048), and the other end of the spectrometer is connected to an output device (computer). The synthesized gold nanosphere solution is immersed in the pear-shaped structure to monitor the modification of the pear-shaped structure in real time. In other embodiments, the light source can be an incandescent lamp, an LED lamp, etc.

[0106] Nanogold can enhance the excitation of optical fiber LSPR, thereby improving the refractive index sensitivity of optical fiber probes. By adjusting the size of the optical fiber LSPR peak, the coverage of nanogold on the optical fiber surface can be adjusted, and the optical fiber probe with the best performance can be optimized, which is conducive to the development and realization of monitoring of the coagulation process.

[0107] The present invention has no limitation on the type and shape of nanometals, and it is preferred that the nanometals can enhance the excitation effect of LSPR. Since the embodiments are not exhaustive, this embodiment takes gold nanospheres as an example.

[0108] The results are shown in the following table:

[0109]

[0110] It can be seen that with the modification of gold nanospheres, the refractive index sensitivity will be greatly improved, but limited by the performance of the detection spectrometer, the pear-shaped fiber LSPR monitoring stability will decrease after greater than 1.2 au, the spectral fluctuation will become larger, and the detection accuracy will decrease.

[0111] Example 3 Prothrombin time (PT) monitoring experiment

[0112] The PT monitoring method includes the following steps:

[0113] (1) Save the reference spectrum;

[0114] (2) taking a sample and immersing the pear-shaped structure in the sample;

[0115] (3) After the spectrum stabilizes, the prothrombin reagent is quickly added and data is collected in real time.

[0116] The details are as follows:

[0117] Collect blood from the subjects. Carefully mix 1 part sodium citrate with 9 parts whole blood to avoid bubbles, centrifuge at 1500×g for at least 15 minutes at room temperature. Take the supernatant and seal it at room temperature. Store the serum in a -80℃ refrigerator.

[0118] In other embodiments, in order to achieve home monitoring, fingertip blood can be collected for testing. To improve the accuracy of the test, a fingertip centrifuge must be used, or other methods must be used to obtain serum.

[0119] Removing blood cells from peripheral blood by centrifugation can help improve the accuracy of PT monitoring.

[0120] Connect the detection device. Use a mechanical joint to connect the pear-shaped optical fiber LSPR according to the method of optical fiber connection. Open the spectrometer software on the computer, create a new absorption measurement spectrum, and set the parameters; save a spectrum every 0.02 seconds, turn on the light source, and save the reference spectrum and dark spectrum with clean water as a reference. Add the preheated plasma sample to a 2μl to 10μl centrifuge tube, and then place the optical fiber into the centrifuge tube with the optical fiber head completely in contact with the plasma sample. Start collecting data at a frequency of 10ms / time. Wait for about 10s, and quickly add 4μl of prothrombin reagent after the spectrum stabilizes. The total data collection time does not exceed 1min.

[0121] Because the maximum outer diameter of the pear-shaped structure is below 0.5 mm, due to its extremely high refractive index sensitivity, it can be detected without further reinforcement of metal nanomaterials.

[0122] Therefore, in this embodiment, a pear-shaped optical fiber with a maximum outer diameter of 0.6 mm is selected, and the maximum LSPR absorption peaks of the pear-shaped optical fiber modified with gold nanospheres are 0.2, 0.4, 0.6, 0.8, 1, and 1.2. When the LSPR absorption spectrum of the pear-shaped optical fiber exceeds 1.2, the results are as follows: Figure 3 As shown, the spectrum is stable and the detection efficiency is high.

[0123] Using the same method, pear-shaped optical fibers with maximum outer diameters of 0.7 mm and 0.8 mm were modified with gold nanospheres. The maximum absorption peaks of the LSPR of the pear-shaped optical fibers were 0.2, 0.4, 0.6, 0.8, 1, and 1.2. When the absorption peaks exceeded 1.2, the LSPR absorption spectrum of the pear-shaped optical fiber would be unstable. The spectra were stable when the absorption peaks were below 1.2.

[0124] The stability of the spectrum of the pear-shaped optical fiber modified with nano-gold is more easily affected by the environment. The LSPR maximum absorption peak is below 1.2, which can ensure that the spectrum remains stable under the detection of lower resolution spectra and can be suitable for more detection environments.

[0125] The present invention explores the pear-shaped fiber LSPR, including refractive index sensitivity and monitoring stability. The combination of various conditions enables rapid high-precision monitoring using only a low-precision spectrometer, for example, obtaining the slight change in refractive index accompanying the coagulation process of human serum within 1 minute.

[0126] Example 4: Consistency Experiment

[0127] Ten clinical serum samples were collected and measured using both the laboratory method and the fiber optic sensor method. In order to match the laboratory method, the PT value measured by the fiber optic sensor method was normalized. The normalization equation is:

[0128] normalizedPT=n*PT

[0129] The coefficient n is the ratio of the PT value measured by the laboratory method to the PT value measured by the method of the present invention.

[0130] The fiber optic sensor method measures the normalized PT value instead of directly measuring the PT value.

[0131] The results are as follows Figure 4 As shown in the results, the results measured by the two methods have good consistency, which is expected to be used for home monitoring of INR values.

[0132] Example 5 Repeatability Experiment

[0133] (a) Pear-shaped fiber LSPR recovery rate test

[0134] The optical fiber after monitoring the serum in Example 3 was cleaned with clean water. After cleaning, a pear-shaped optical fiber with a LSPR peak of 0.6 au was selected. A batch of 10 fibers were placed in sucrose solutions with different refractive indices, and the optical fiber absorption spectrum was recorded. The refractive index sensitivity was calculated and the average value was obtained. The final refractive index sensitivity was 48.51 au / RIU, which was within 5% of the refractive index sensitivity loss before monitoring, indicating a good recovery rate and the ability to be reused. After home monitoring, it only needs to be directly cleaned before the next use.

[0135] (b) Pear-shaped fiber repeatability test

[0136] The optical fiber after monitoring the serum in Example 3 was cleaned with aqua regia and dried. Then, pear-shaped optical fibers with a maximum outer diameter of 0.65 mm were selected. A batch of 10 pear-shaped optical fibers were placed in sucrose solutions with different refractive indices. The optical fiber absorption spectrum was recorded, and the refractive index sensitivity was calculated and the average value was obtained. The final refractive index sensitivity was 40.83 au / RIU, which was within 5% of the refractive index sensitivity loss before monitoring, indicating a stable recovery rate and ability to be reused.

[0137] In summary, it can be seen that the pear-shaped optical fiber and the pear-shaped optical fiber LSPR of the present invention have stable performance, can be reused, and reduce monitoring costs.

Claims

1. A pear-shaped optical fiber LSPR, characterized in that: The pear-shaped fiber LSPR is formed by processing a multimode optical fiber, has a peak value below 3 au, contains a pear-shaped structure and an optical fiber structure, the optical fiber structure is connected to the pear-shaped structure, and the maximum outer diameter of the pear-shaped structure is 0.4 mm -0.8 mm; preferably, the pear-shaped fiber LSPR peak value is below 1.2 au, and more preferably, the pear-shaped fiber LSPR peak value is 0.2-1.2 au.

2. The pear-shaped optical fiber LSPR according to claim 1, characterized in that: The cladding of the pear-shaped optical fiber LSPR is 125 μm.

3. The pear-shaped optical fiber LSPR according to claim 1 or 2, characterized in that: The pear-shaped structure is composed of a SiO2 fiber core, a SiO2 cladding and a nano-metal material. The SiO2 cladding wraps around the outer layer of the SiO2 fiber core, and the nano-metal material is modified on the SiO2 cladding.

4. A sensor, characterized in that: The sensor comprises the pear-shaped fiber LSPR according to claim 1 or 2.

5. A monitoring device, characterized in that: The monitoring device comprises the sensor according to claim 4.

6. The monitoring device according to claim 5, characterized in that: The monitoring device comprises a light source, a detector, an output device, the pear-shaped optical fiber LSPR as described in claim 1 or 2, and an optical fiber jumper. The pear-shaped optical fiber LSPR is connected to the light source and one end of the detector respectively through the optical fiber jumper, and the other end of the detector is connected to the output device through the optical fiber jumper to output the monitoring results; preferably, the light energy of the light source is 10 mWh - 100 mWh.

7. A method for preparing a pear-shaped optical fiber LSPR according to any one of claims 1 to 3, comprising the following steps: Take the optical fiber and remove part of the plastic outer layer; Bend the part with the plastic outer layer removed at high temperature into a pear-shaped structure; After functionalizing the pear-shaped structure in the above step (2), the nano-metal material is modified to form a pear-shaped optical fiber LSPR.

8. A monitoring method, characterized in that: Monitoring using the monitoring device as claimed in claim 5 or 6 comprises the following steps: Save reference spectra; Taking a sample, and immersing the pear-shaped structure as described in any one of claims 1 to 3 in the sample; After the spectrum stabilizes, the prothrombin reagent is quickly added and data is collected in real time.

9. The pear-shaped optical fiber LSPR according to any one of claims 1 to 3, the sensor according to claim 4 or the monitoring device according to claim 5 is used for monitoring the coagulation process.

10. Use of the pear-shaped fiber LSPR according to any one of claims 1 to 3, the sensor according to claim 4 or the monitor according to claim 5 in atrial fibrillation monitoring.

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