An implantable optoelectronic sensor for luminescence response

Abstract

This invention discloses an implantable photoelectric sensor for luminescence response, relating to the field of biomedical photoelectric detection technology. By employing a lateral silicon photodetector with a coplanar electrode structure, the device can be directly integrated onto a circuit substrate via surface mounting, thus avoiding the wire bonding process required for traditional photodiodes and significantly simplifying device packaging and integration. The fabrication process of this photodetector does not require complex micro-nano lithography, multilayer alignment, or structure transfer processes; it can be achieved using only conventional semiconductor processes, offering advantages such as simple fabrication, low cost, and ease of large-scale manufacturing. Through integration with a micro-light source and wireless signal processing module, it can record luminescence signals within the body in real time during free biological activity. Furthermore, the luminescence response mechanism has good versatility and can be extended to the detection of various physiological or chemical signals such as oxygen concentration, ion changes, and metabolic processes.

Description

Technical Field

[0001] This invention relates to the field of biomedical optoelectronic detection technology, and in particular to an implantable optoelectronic sensor for luminescence response based on a coplanar electrode lateral silicon photodetector. Background Technology

[0002] With the development of neuroscience and biomedical engineering, the demand for dynamic monitoring of neural activity and metabolic processes in organisms is constantly increasing. In vivo detection methods based on luminescent signals (such as fluorescence or phosphorescence) have been widely used in neural activity recording and metabolic process monitoring, and have become an important technical means for studying brain function and physiological regulation.

[0003] Sych Y et al. (Sych Y, Chernysheva M, Sumanovski LT, et al. High-density multi-fiber photometry for studying large-scale brain circuit dynamics[J]. Nature Methods, 2019, 16(6): 553–560.) proposed a high-density multi-fiber photometry system that can simultaneously record neural activity in multiple brain regions. This method connects an external light source to a detector via optical fiber to acquire and transmit fluorescence signals, effectively reflecting neuronal population activity. However, this technology relies on optical fiber connections to external devices, limiting the free movement of experimental animals. Furthermore, the overall system remains relatively complex, hindering long-term implantation and miniaturization applications.

[0004] To achieve higher integration in vivo optical detection, Rynes ML et al. (Rynes ML, Surinach DA, Linn S, et al. Miniaturized head-mounted microscope for whole-cortexmesoscale imaging in freely behaving mice[J]. Nature Methods, 2021, 18: 417–425.) proposed a head-mounted miniature fluorescence imaging system. By integrating miniature optical components with a CMOS image sensor, they achieved real-time imaging of neural activity in the mouse cerebral cortex. This system has high spatial resolution and a large field of view, making it valuable for neural activity research. However, such head-mounted imaging systems are typically relatively large, rely on a complete optical imaging path and CMOS array detection structure, have complex system integration, high power consumption, and are difficult to further miniaturize to the scale of deeply implantable microprobes, thus limiting their implantable applications.

[0005] Cai X et al. (Cai X, Zhang HJ, Wei PH, et al. A wireless optoelectronic probe to monitor oxygenation in deep brain tissue [J]. Nature Photonics, 2024, 18(5): 492–500.) reported a wireless optoelectronic probe system that integrates a micro-light-emitting device and a photoelectric detection unit to achieve real-time monitoring of oxygenation status in deep brain tissue and can be used in experiments on freely moving animals. This system is of great significance in in vivo optical signal detection, but its device structure relies on the integration of multilayer functional materials and complex micro-nano fabrication processes (such as device transfer, heterogeneous integration, etc.), resulting in a relatively cumbersome preparation process and high process complexity, which to some extent limits its large-scale manufacturing.

[0006] Furthermore, implantable optogenetic modulation technology based on micro-LEDs has developed rapidly in recent years. Kim TI et al. (Kim TI, McCall JG, Jung YH, et al. Injectable, cellular-scale optoelectronics with applications for wireless optogenetics[J]. Science, 2013, 340(6129): 211–216.) reported an implantable wireless optoelectronic device that achieves optogenetic stimulation of neural tissue through the integration of a micro-LED array, and can be applied to experiments in freely moving animals. This type of μLED system has significant advantages in miniaturization and wireless functionality; however, existing research mainly focuses on the photostimulation function, lacking a matching integrated light signal detection module, making it difficult to achieve an integrated "stimulation-detection" closed-loop system.

[0007] On the other hand, in existing photoelectric detection solutions, photodetectors mostly adopt a vertical structure, and their electrodes are usually located on the top and bottom sides of the device. They need to be electrically connected by wire bonding or complex packaging methods, which not only increases the difficulty of device integration, but may also block the incident light and reduce the efficiency of light signal acquisition, thus limiting their application in miniaturized, wireless implantable systems.

[0008] In summary, although existing in vivo emission signal detection technologies have made some progress in terms of sensitivity and functional integration, they still have the following shortcomings: First, the system relies on fiber optic cables or external equipment connections, which limits its application under conditions of free behavior. Second, the device structure is complex, and the fabrication process relies on multi-step micro-nano fabrication or heterogeneous integration processes, making it difficult to achieve low-cost mass production. Third, the traditional structure of photodetectors is not conducive to efficient optical signal acquisition and simplified integration and packaging.

[0009] Therefore, how to provide a miniature photoelectric probe that is simple in structure, easy to manufacture, compatible with standard processes, and suitable for wireless implantation applications to achieve stable detection of in vivo luminescent signals is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0010] In view of the above problems, the present invention provides an implantable photoelectric sensor for luminescence response to overcome or at least partially solve the above problems. It solves the problems of existing bio-optical detection systems being large in size, complex in structure, cumbersome in fabrication processes, and difficult to achieve wireless implantation applications.

[0011] This invention provides the following solution: An implantable photoelectric sensor for luminescence response, comprising: Flexible substrate; A light source module is disposed on the flexible substrate and is used to emit excitation light; A light-emitting material layer is disposed on the outermost front end of the flexible substrate, and the light-emitting material layer is used to generate a light emission signal under the action of the excitation light; A photoelectric detection module is disposed on the flexible substrate and is used to receive the light emission signal and convert it into an electrical signal; The photodetector module is a lateral photodetector based on a silicon substrate and responsive to the visible light band. The lateral photodetector includes p-type photodetectors located on the same surface of the silicon substrate. + Doped region and n + The doped region, the p + The doped region and the n + The doped regions are respectively connected to p + Zone electrode and n + Region electrode, so that the p + The region electrode and the n + The area electrodes form a coplanar electrode structure.

[0012] Preferably, the lateral photodetector is formed by ion implantation doping. + The doped region and the n + The doped region is formed by a metal deposition process. + The region electrode and the n + Zone electrode; The p+ The region electrode adopts a Ti / Au metal structure, wherein the n + The zone electrode adopts a Mg / Ti / Au metal structure to form an ohmic contact with low contact resistance.

[0013] Preferably, the luminescent material layer comprises an environmentally sensitive luminescent material, wherein the environmentally sensitive luminescent material comprises an oxygen-sensitive phosphorescent material [Ru(dpp)3]Cl2 for generating an oxygen-dependent phosphorescent signal; The luminescence intensity or luminescence lifetime of the environmentally sensitive luminescent material changes with variations in external physical or chemical parameters; the environmentally sensitive luminescent material is formed on the outermost front layer of the flexible substrate through a dip-coating or dip-coating process.

[0014] Preferably, the light source module includes a micro light-emitting diode disposed on the surface of the flexible substrate by surface mounting.

[0015] Preferably, the photoelectric detection module and the light source module are integrated on the flexible substrate by surface mounting; the photoelectric detection module has a size of 300 micrometers × 300 micrometers, the overall width of the photoelectric sensor is 400 micrometers, and the overall thickness is 200 micrometers.

[0016] Preferably, the flexible substrate is a polyimide multilayer structure with a thickness of 110 micrometers.

[0017] Preferably, the implantable photoelectric probe further includes a biological sealing layer, which covers the surface of the implantable photoelectric probe. The biological sealing layer is made of Parylene-C and has a thickness of 12 micrometers.

[0018] Preferably, the device further includes a filter layer disposed on the photoelectric detection module to suppress the excitation light and selectively transmit the emission signal.

[0019] Preferably, the filter layer comprises an absorption filter layer of photoresist SU8 3005 containing the absorption dye ABS473, wherein the transmittance of the absorption filter layer at the wavelength of the excitation light is less than 1%, and the transmittance at the wavelength of the emission signal is greater than 70%. The preparation process of the filter layer includes spin-coating the filter adhesive onto the surface of the photoelectric detection module at parameters of 500 rpm for 6 s and 3000 rpm for 30 s, followed by hard curing at 90 ℃.

[0020] Preferably, a signal processing module is provided, which is electrically connected to the photoelectric detection module. The signal processing module includes a transimpedance amplifier circuit for amplifying and converting the electrical signal from analog to digital. A data transmission module is connected to the signal processing module. The data transmission module is a Bluetooth wireless communication module used to wirelessly transmit the processed signal to an external terminal device.

[0021] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: This invention provides an implantable photoelectric sensor for luminescence response. By employing a lateral silicon photodetector with a coplanar electrode structure, the device can be directly integrated onto a circuit substrate via surface mounting, thus avoiding the wire bonding process required for traditional photodiodes and significantly simplifying device packaging and integration. The fabrication process of this photodetector does not require complex micro-nano lithography, multilayer alignment, or structure transfer processes; it can be achieved using only conventional semiconductor processes, offering advantages such as simple fabrication, low cost, and ease of large-scale manufacturing. By integrating with a micro-light source and a wireless signal processing module, it can record luminescence signals within the body in real time during free biological activity. Furthermore, the luminescence response mechanism has good versatility and can be extended to the detection of various physiological or chemical signals such as oxygen concentration, ion changes, and metabolic processes.

[0022] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of an implantable photoelectric sensor for light emission response provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the lateral silicon photodetector structure provided in an embodiment of the present invention; Figure 3 This is a diagram showing the device structure dimensions and simulation distribution provided in the embodiments of the present invention; Figure 4 This is a curve showing the change of doping concentration with depth provided in an embodiment of the present invention; Figure 5 These are current-voltage characteristic curves under different illumination conditions provided in the embodiments of the present invention; Figure 6 This is a graph showing the photoresponse characteristics of a photodetector provided in an embodiment of the present invention. Figure 7 This is a schematic diagram of the device fabrication process provided in an embodiment of the present invention; Figure 8 These are microscopic images of the devices provided in the embodiments of the present invention after fabrication. Figure 9 This is a current-voltage characteristic curve provided in an embodiment of the present invention; Figure 10 This is a graph showing the relationship between optical response and optical power density provided in an embodiment of the present invention; Figure 11 This is the external quantum efficiency spectrum provided in the embodiments of the present invention; Figure 12 These are the current-voltage characteristic curves and physical images of the micro LED provided in the embodiments of the present invention; Figure 13 This is a comparison diagram of the LED emission spectrum and the absorption spectrum of the luminescent material layer provided in the embodiments of the present invention; Figure 14 These are the transmission spectrum of the filter layer, the emission spectrum of the luminescent material layer, and the response characteristic curves of the photodetector provided in the embodiments of the present invention. Figure 15 This is a schematic diagram illustrating the structural composition and fabrication process of the miniature implantable photoelectric probe provided in this embodiment of the invention; Figure 16 This is a structural block diagram of the wireless optical signal detection system provided in an embodiment of the present invention; Figure 17 This is a physical diagram of the system circuit board and probe device provided in an embodiment of the present invention; Figure 18 This is a calibration curve of the intensity of the emitted light signal changing with environmental parameters, provided in an embodiment of the present invention. Figure 19 This is a schematic diagram showing the implantation location of the probe provided in this embodiment of the invention in the mouse brain; Figure 20 This is a schematic diagram of the surgical procedure provided in an embodiment of the present invention; Figure 21 This is a dynamic change curve of the in vivo luminescence signal under different external conditions provided in the embodiments of the present invention; Figure 22 This is a graph showing the change in luminescence signal under external stimulation conditions provided in an embodiment of the present invention; Figure 23 This is a diagram showing the results of synchronous recording of neural electrical signals and light emission signals provided in an embodiment of the present invention.

[0025] In the diagram: 1. Flexible substrate; 2. Light source module; 3. Light-emitting material layer; 4. Photodetector module; 5. Filter layer. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0027] See Figure 1 This invention provides an implantable photoelectric sensor for luminescence response, such as... Figure 1 As shown, the photoelectric sensor may include: Flexible substrate 1; In a specific implementation, the flexible substrate 1 of the present invention can be a polyimide multilayer structure with a thickness of 110 micrometers.

[0028] A light source module 2 is disposed on the flexible substrate 1 and is used to emit excitation light. In a specific implementation, the embodiment of the present invention may provide that the light source module 2 includes a micro light-emitting diode disposed on the surface of the flexible substrate by means of surface mounting.

[0029] A light-emitting material layer 3 is disposed on the outermost front end of the flexible substrate 1. The light-emitting material layer 3 is used to generate a light emission signal under the action of the excitation light. In a specific implementation, the embodiment of the present invention may provide that the light-emitting material layer 3 includes an environment-sensitive light-emitting material, which includes an oxygen-sensitive phosphorescent material [Ru(dpp)3]Cl2 for generating an oxygen-dependent phosphorescent signal. The luminescence intensity or luminescence lifetime of the environmentally sensitive luminescent material changes with variations in external physical or chemical parameters; the environmentally sensitive luminescent material is formed on the outermost front layer of the flexible substrate through a dip-coating or dip-coating process.

[0030] A photoelectric detection module 4 is disposed on the flexible substrate 1. The photoelectric detection module 4 is used to receive the light emission signal and convert it into an electrical signal. In a specific implementation, the photoelectric detection module 4 and the light source module 2 can be integrated on the flexible substrate 1 by surface mounting. The photoelectric detection module 4 has a size of 300 micrometers × 300 micrometers, the overall width of the photoelectric sensor is 400 micrometers, and the overall thickness is 200 micrometers.

[0031] The photodetector module 4 is a lateral photodetector based on a silicon substrate and responsive to the visible light band. The lateral photodetector includes p-type photodetectors located on the same surface of the silicon substrate. + Doped region and n + The doped region, the p + The doped region and the n+ The doped regions are respectively connected to p + Electrode and n + Electrode, so that the p + Electrode and n + The electrodes form a coplanar electrode structure.

[0032] Furthermore, the lateral photodetector is formed by an ion implantation doping process. + The doped region and the n + The doped region is formed by a metal deposition process. + The region electrode and the n + Zone electrode; The p + The region electrode adopts a Ti / Au metal structure, wherein the n + The zone electrode adopts a Mg / Ti / Au metal structure to form an ohmic contact with low contact resistance.

[0033] To further ensure the stability of the device during long-term operation in a biological environment, embodiments of the present invention may provide that the implantable photoelectric probe further includes a biological sealing layer, which covers the surface of the implantable photoelectric probe. The biological sealing layer is made of Parylene-C and has a thickness of 12 micrometers.

[0034] In order to suppress the excitation light and selectively transmit the target emission signal, embodiments of the present invention can provide a filter layer 5, which is disposed on the photoelectric detection module 4 to suppress the excitation light and selectively transmit the emission signal.

[0035] Furthermore, the filter layer 5 includes an absorption filter layer of photoresist SU8 3005 containing the absorption dye ABS473. The transmittance of the absorption filter layer at the wavelength of the excitation light is less than 1%, and the transmittance at the wavelength of the emission signal is greater than 70%. The preparation process of the filter layer 5 includes spin-coating the filter adhesive onto the surface of the photoelectric detection module at parameters of 500 rpm for 6 s and 3000 rpm for 30 s, followed by hard curing at 90 ℃.

[0036] To facilitate signal transmission, this embodiment of the invention can provide a signal processing module, which is electrically connected to the photoelectric detection module 4. The signal processing module includes a transimpedance amplifier circuit for amplifying and converting the electrical signal from analog to digital. A data transmission module is connected to the signal processing module. The data transmission module is a Bluetooth wireless communication module used to wirelessly transmit the processed signal to an external terminal device.

[0037] The implantable photoelectric sensor for light emission response provided in this embodiment of the invention employs a lateral silicon photodetector with a coplanar electrode structure in its optical signal detection module. The silicon photodetector forms a lateral PN junction structure on the surface of a silicon substrate. + area and n + The electrodes are located on the same surface, achieving a coplanar electrode layout and supporting surface mounting. The photodetector is simple to fabricate, requiring only conventional doping and metal deposition processes, eliminating the need for complex micro / nano lithography, transfer, or heterogeneous integration. This results in low fabrication cost, strong process compatibility, and ease of large-scale manufacturing. The luminescent material layer generates a characteristic luminescent signal under excitation light. This signal is received by the silicon photodetector after passing through a filter layer and converted into an electrical signal. The probe further integrates a wireless readout system, enabling signal amplification and wireless transmission, and stably recording dynamic changes in the luminescent signal within the body. This invention features a simple structure, small size, and easy integration, making it suitable for miniaturized, wireless implantable bio-optical detection systems.

[0038] The following section provides a detailed description of the implantable photoelectric sensor for light emission response provided in this embodiment of the invention, using the example of setting an optical filter layer, a signal processing module, and a data transmission module.

[0039] like Figure 1 As shown, the implantable photoelectric sensor for luminescence response provided in this embodiment of the invention may include a flexible substrate 1, a light source module 2, a luminescent material layer 3, a photodetector module 4, a filter layer 5, a signal processing module, and a data transmission module. The flexible substrate, which can be implanted into biological tissue, allows for direct integration onto the flexible substrate via surface mounting, thereby avoiding the complex packaging and interconnection processes required for traditional vertical structure photoelectric devices. Furthermore, it is integrated with a miniature light source and luminescent material to construct a miniaturized photoelectric probe, enabling in-situ recording of luminescence signals within biological tissue.

[0040] The light source module 2 is used to provide excitation light; it may include a miniature light-emitting diode (LED) for providing excitation light. The luminescent material layer 3 is disposed on the outermost layer at the front end of the flexible substrate structure and is used to generate a light emission signal under the action of excitation light; the light emission signal is received by a silicon photodetector and converted into an electrical signal. The silicon substrate is an n-type single-crystal silicon substrate with a crystal orientation of <100> Its resistivity is 1–10 Ω·cm.

[0041] The photoelectric detection module 4 is used to receive the light emission signal and convert it into an electrical signal; it is a transverse silicon photodetector with a coplanar electrode structure.

[0042] The signal processing module is electrically connected to the photoelectric detection module and is used to amplify and convert the electrical signal from analog to digital. The data transmission module is connected to the signal processing module and is used to wirelessly transmit the processed signal to an external terminal device. The photodetector module is a lateral photodetector based on a silicon substrate, which forms a lateral PN junction structure on the surface of the silicon substrate, and p + area and n + The regional electrodes are set on the same surface to form a coplanar electrode structure, thereby supporting surface mount integration without the need for complex micro-nano lithography, multi-layer alignment or structure transfer processes. The light source module 2, the luminescent material layer 3, and the photoelectric detection module 4 are integrated on the flexible substrate 1 of the micro probe structure to realize wireless implantable in vivo luminescent signal recording.

[0043] The photoelectric detection module 4 is a lateral PN junction structure, and its p + area and n + The regions are disposed on the same silicon substrate surface and form a coplanar electrode layout. The photodetector module adopts a silicon substrate-based photodiode structure, which has good response capability in the visible light band. Specifically, it includes a silicon substrate, a p-type photodiode disposed on the surface of the silicon substrate, and a photodiode. + Doped regions and n + The doped region, the p + area and n + A lateral PN junction structure is formed on the surface of a silicon substrate; metal electrodes are connected to each other, and the two electrodes are located on the same surface of the silicon substrate, thereby forming a coplanar electrode structure. Furthermore, the photodetector can be fabricated by ion implantation doping and metal deposition processes, without the need for complex micro-nano lithography alignment, multilayer structure transfer or heterogeneous integration processes, thereby significantly reducing manufacturing difficulty and cost, and improving process compatibility and scalability.

[0044] The p + The region electrode adopts a Ti / Au metal structure, wherein the n + The zone electrode adopts a Mg / Ti / Au metal structure to form an ohmic contact with low contact resistance.

[0045] The luminescent material layer 3 is sensitive to environmental changes, and its luminescence intensity or lifetime changes with variations in external physical or chemical parameters. This luminescent material layer exhibits environmental responsiveness and is disposed above the silicon photodetector to generate corresponding luminescent signals under changing external environmental conditions. In a specific embodiment, the luminescent material layer is an oxygen-sensitive phosphorescent material [Ru(dpp)3]Cl2 containing a ruthenium complex, formed as a sensitive layer by dip-coating to generate an oxygen-dependent phosphorescent signal.

[0046] The photoelectric detection module 4 is provided with a filter layer 5, which is used to suppress excitation light and selectively transmit the target emission signal.

[0047] The light source module 2 is a miniature light-emitting device used to provide stable excitation light to excite the light-emitting material to generate light signals. It is integrated with a silicon photodetector on a flexible substrate and connected via surface mounting, thereby forming a miniaturized, highly integrated probe structure.

[0048] An optical filter layer 5 is provided on the surface of the photodetector, which is deposited by spin coating to suppress excitation light and selectively transmit the target emission signal.

[0049] The signal processing module includes a transimpedance amplifier circuit for amplifying and digitizing the electrical signal output by the photodetector module. The data transmission module is a wireless communication module for real-time wireless data transmission. The photodetector probe can be integrated with a wireless signal readout circuit, converting the photocurrent signal output by the photodetector into a voltage signal through the transimpedance amplifier, and then transmitting the data in real-time through the wireless communication module, thereby achieving a wireless implantable working mode.

[0050] The photoelectric detection module and the light source module are integrated on a flexible substrate by surface mounting to achieve miniaturization and high integration of the device. The overall dimensions are 400 μm wide and 200 μm thick.

[0051] The following description, in conjunction with the accompanying drawings, illustrates the fabrication method of the implantable photoelectric sensor for luminescence response provided by this invention and the verification of the invention's effectiveness.

[0052] Figure 1 This is a schematic diagram of the overall probe structure, including a flexible substrate 1, a light source module 2 (micro-LED light source), a light-emitting material layer 3, a photodetector module 4 (lateral silicon photodetector), and a filter layer 5. The micro-LED provides excitation light, which excites the light-emitting material to generate a light emission signal. This signal is then received by the photodetector after passing through the filter layer and converted into an electrical signal. Figure 2 This is a schematic diagram of a lateral silicon photodetector structure, which includes an n-type silicon substrate and a p-type silicon substrate. + Doped regions and n + The doped region forms a lateral PN junction structure on the substrate surface. + area and n + The regions are connected to metal electrodes respectively and are located on the same surface, thus forming a coplanar electrode structure. Figure 3 and Figure 4 The simulated device structure dimensions and doping distribution are shown. By adjusting the doping concentration and distribution, the carrier transport process can be optimized, thereby improving the photoelectric conversion efficiency. Figure 5 and Figure 6 The simulation results demonstrate the current-voltage characteristics and photoresponse characteristics of the device under different illumination conditions, showing that the device has good linear response capability.

[0053] like Figure 7 As shown, this invention further provides a manufacturing process for silicon-based photodetectors. First, p-type photodetectors are formed on a silicon wafer through ion implantation and annealing processes. + area and n + The area is then formed; electrodes are then formed through a metal deposition process; finally, individual devices are obtained through wafer dicing. Figure 8 The image shows a microscopic image of the device, approximately 300 μm × 300 μm in size. Figure 9 , Figure 10 , Figure 11 The electrical and optical properties of the device were demonstrated, showing that it has good response characteristics in the visible light range.

[0054] This invention features an optical matching design between the light source module and the luminescent material layer. Figure 12 The electrical performance and luminescent characteristics of micro LEDs were demonstrated. Figure 13 This indicates that the LED emission spectrum and the absorption spectrum of the luminescent material have a good matching relationship; Figure 14 The transmission spectrum and emission signal characteristics of the filter layer were demonstrated, thus effectively suppressing excitation light interference.

[0055] like Figure 15 As shown in section a, this invention further presents the structural design and fabrication process of the oxygen partial pressure detection probe. First, an LED and a photodetector are integrated on a flexible polyimide (PI) substrate via surface mounting; then, a filter layer is deposited on the detector surface; finally, a luminescent material layer is coated on the outermost layer. The completed probe is shown in [image / description]. Figure 15 As shown in section b.

[0056] The silicon-based detector fabrication process provided in this embodiment requires only four photolithographic masks, and the probe fabrication process does not require expensive wafer bonding or complex thinning and transfer processes. Compared with existing technologies (such as the heterogeneous integrated probes disclosed by Cai X et al.), as shown in Table 1, this invention reduces critical steps by approximately 60%. This process simplification not only significantly improves production yield but also greatly reduces the reliance on high-precision alignment equipment, thereby enabling low-cost mass production.

[0057] Table 1. Comparison of the present invention's solution with existing advanced wireless photoelectric probe technologies.

[0058] In this embodiment, the detector employs a coplanar electrode design, supporting surface mounting and eliminating the need for the wire bonding height required by traditional vertical structures, typically 150-250 μm. This allows the overall probe encapsulation thickness to be reduced to less than 300 μm. In implantable applications, this quantified reduction in thickness can significantly reduce compression damage to biological tissues and rejection reactions.

[0059] In a specific embodiment, the filter layer uses SU8 3005 photoresist containing the absorbent dye ABS473. The preparation process involves spin-coating the filter solution onto the surface of the photodetector at parameters of 500 rpm for 6 s and 3000 rpm for 30 s, followed by hard curing at 90 °C. Tests show that the transmittance of this filter layer is less than 1% at 475 nm and greater than 70% at 625 nm.

[0060] In a specific embodiment, the luminescent material layer includes the oxygen-sensitive phosphorescent material [Ru(dpp)3]Cl2, which is mixed with the PDMS matrix at a mass ratio of 1:10 and coated onto the detector via a dip-coating method. Because the luminescent layer and the detector have a direct-contact stacked structure, light loss due to interface reflection is minimized. This material produces orange-red phosphorescence under blue light excitation, and its luminescence intensity and lifetime vary with oxygen concentration. By detecting changes in this luminescence signal, quantitative characterization of the local oxygen partial pressure can be achieved.

[0061] In this embodiment, the detailed structure of the flexible substrate is 25 μm PI / 18 μm Cu / 25 μm PI / 18 μm Cu / 25 μm PI, totaling approximately 110 μm. By controlling the thickness to the micrometer level, the bending stiffness of the probe is significantly reduced, allowing it to adapt to the minute pulsations of biological tissues after implantation, such as brain fluctuations caused by respiration or heartbeat, thus reducing the inflammatory response of the tissue. Furthermore, a 12 μm thick Parylene-C bio-sealing layer is deposited on the entire surface of the probe, forming a double waterproof and insulating barrier, ensuring the stability of the device during long-term operation in a biological environment.

[0062] like Figure 16 , Figure 17 As shown, this invention constructs a wireless optical signal detection system. The system includes a transimpedance amplifier, an analog-to-digital converter, and a wireless Bluetooth communication module, all mounted on a system circuit board. The output signal from the photodetector is amplified and digitized, then wirelessly transmitted to an external terminal for real-time data acquisition.

[0063] To verify the detection capability of the probe described in this invention, this embodiment conducts calibration experiments on its response characteristics under different oxygen concentration conditions. In an in vitro environment, the oxygen-sensitive phosphorescent probe is placed in a sealed gas chamber. By adjusting the mixing ratio of oxygen and nitrogen, blue LEDs are activated for excitation under different oxygen concentration conditions, and the output signal of the photodetector is recorded. Figure 18 As shown, the detection signal intensity exhibits a good functional relationship with the change of oxygen partial pressure (consistent with the Stern-Volmer relationship), indicating that the present invention can achieve quantitative detection of oxygen partial pressure.

[0064] To verify the applicability of the probe of this invention in the in vivo environment, this embodiment uses mice as experimental subjects to conduct in vivo tests. Figure 19 As shown, the photoelectric probe was implanted into the CA3 region of the mouse hippocampus, and simultaneously, electrical stimulation electrodes were implanted in the contralateral brain region to induce changes in neural activity. In the specific implementation process, as follows... Figure 20 As shown, the experimental animals were first anesthetized and fixed on a stereotaxic apparatus. After exposing the skull, the brain region was located and drilled according to the coordinates. Then, the probe was slowly implanted into the target brain region and fixed with dental cement. At the same time, reference electrodes and stimulation electrodes were implanted. After the animals recovered, signal acquisition experiments were conducted.

[0065] During the experiment, different oxygen supply states were constructed by adjusting the volume fraction of oxygen in the inhaled gas. For example... Figure 21 , Figure 22 , Figure 23 As shown, the detection results demonstrate that the probe of this invention can stably acquire luminescent signals in vivo and produce repeatable dynamic responses to changes in external conditions. Furthermore, by applying electrical stimulation to induce enhanced neural activity, dynamic modulation characteristics of the luminescent signal over time can be observed, indicating that the probe can reflect local metabolic or physiological changes. Therefore, compared to other micro-photodetectors, the lateral coplanar electrode structure of this invention has significant advantages in terms of device integration complexity, packaging difficulty, and device size, making it more suitable for miniaturized and wireless implantable applications. The probe can also be used for real-time monitoring of luminescent signals in vivo, exhibiting good stability and applicability.

[0066] In summary, the implantable photoelectric sensor for luminescence response provided by this invention, through the use of a lateral silicon photodetector with a coplanar electrode structure, enables the device to be directly integrated onto the circuit substrate via surface mounting, thereby avoiding the wire bonding process required by traditional photodiodes and significantly simplifying the device packaging and integration. The fabrication process of this photodetector does not require complex micro-nano lithography, multilayer alignment, or structure transfer processes; it can be achieved using only conventional semiconductor processes, offering advantages such as simple process, low cost, and ease of large-scale manufacturing. By integrating with a micro-light source and a wireless signal processing module, it can record luminescence signals within the body in real time during free biological activity. Furthermore, the luminescence response mechanism has good versatility and can be extended to the detection of various physiological or chemical signals such as oxygen concentration, ion changes, and metabolic processes.

[0067] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0068] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

[0069] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An implantable photoelectric sensor for luminescence response, characterized in that, include: Flexible substrate; A light source module is disposed on the flexible substrate and is used to emit excitation light; A light-emitting material layer is disposed on the outermost front end of the flexible substrate, and the light-emitting material layer is used to generate a light emission signal under the action of the excitation light; A photoelectric detection module is disposed on the flexible substrate and is used to receive the light emission signal and convert it into an electrical signal; The photodetector module is a lateral photodetector based on a silicon substrate and responsive to the visible light band. The lateral photodetector includes p-type photodetectors located on the same surface of the silicon substrate. + Doped region and n + The doped region, the p + The doped region and the n + The doped regions are respectively connected to p + Zone electrode and n + Region electrode, so that the p + The region electrode and the n + The area electrodes form a coplanar electrode structure.

2. The implantable photoelectric sensor for luminescence response according to claim 1, characterized in that, The lateral photodetector is formed by ion implantation doping process. + The doped region and the n + The doped region is formed by a metal deposition process. + The region electrode and the n + Zone electrode; The p + The region electrode adopts a Ti / Au metal structure, wherein the n + The zone electrode adopts a Mg / Ti / Au metal structure to form an ohmic contact with low contact resistance.

3. The implantable photoelectric sensor for luminescence response according to claim 1, characterized in that, The luminescent material layer includes an environmentally sensitive luminescent material, which includes an oxygen-sensitive phosphorescent material [Ru(dpp)3]Cl2 for generating an oxygen-dependent phosphorescent signal; The luminescence intensity or luminescence lifetime of the environmentally sensitive luminescent material changes with variations in external physical or chemical parameters; The environmentally sensitive luminescent material is formed on the outermost front layer of the flexible substrate through a dip-coating or dip-coating process.

4. The implantable photoelectric sensor for luminescence response according to claim 1, characterized in that, The light source module includes miniature light-emitting diodes that are surface-mounted onto the surface of the flexible substrate.

5. The implantable photoelectric sensor for luminescence response according to claim 1, characterized in that, The photoelectric detection module and the light source module are integrated on the flexible substrate by surface mounting. The photoelectric detection module has a size of 300 micrometers × 300 micrometers, the overall width of the photoelectric sensor is 400 micrometers, and the overall thickness is 200 micrometers.

6. The implantable photoelectric sensor for luminescence response according to claim 1, characterized in that, The flexible substrate is a polyimide multilayer structure with a thickness of 110 micrometers.

7. The implantable photoelectric sensor for luminescence response according to claim 1, characterized in that, The implantable photoelectric probe also includes a biological sealing layer, which covers the surface of the implantable photoelectric probe. The biological sealing layer is made of Parylene-C and has a thickness of 12 micrometers.

8. The implantable photoelectric sensor for luminescence response according to claim 1, characterized in that, It also includes a filter layer, which is disposed on the photoelectric detection module to suppress the excitation light and selectively transmit the emission signal.

9. The implantable photoelectric sensor for luminescence response according to claim 8, characterized in that, The filter layer comprises an absorption filter layer of photoresist SU8 3005 containing the absorption dye ABS473. The transmittance of the absorption filter layer at the wavelength of the excitation light is less than 1%, and the transmittance at the wavelength of the emission signal is greater than 70%. The preparation process of the filter layer includes spin-coating the filter adhesive onto the surface of the photoelectric detection module at parameters of 500 rpm for 6 s and 3000 rpm for 30 s, followed by hard curing at 90 ℃.

10. The implantable photoelectric sensor for luminescence response according to claim 1, characterized in that, Also includes: A signal processing module is electrically connected to the photoelectric detection module. The signal processing module includes a transimpedance amplifier circuit for amplifying and converting the electrical signal from analog to digital. A data transmission module is connected to the signal processing module. The data transmission module is a Bluetooth wireless communication module used to wirelessly transmit the processed signal to an external terminal device.

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