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Ultrasensitive Detection of Biomarkers by Using a Molecular Imprinting Based Capacitive Biosensor
Published on: February 16, 2018
Electrochemical Degradation of Molecularly Imprinted Polymers for Future Applications of Inflammation Sensing in
Minh-Hai Nguyen1, Adrian Onken1, Jan Sündermann2
1Department of Otolaryngology and Cluster of Excellence "Hearing4all", Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany.
Insights
Researchers developed new molecular imprinted polymers (MIPs) for cochlear implants (CIs) to detect inflammation. These conductive, biocompatible, and degradable MIPs offer a promising biosensing solution for CIs.
Area of Science:
- Biomaterials Science
- Neuroscience
- Chemical Engineering
Background:
- Postoperative inflammation after cochlear implant (CI) surgery can be monitored using proinflammatory markers.
- Prompt detection of inflammation is vital for timely anti-inflammatory treatment.
- Molecular imprinted polymers (MIPs) offer a potential solution for in-situ inflammation detection on CI electrodes.
Purpose of the Study:
- To synthesize and characterize conductive, biocompatible, and degradable MIPs for detecting inflammation markers in CI.
- To evaluate the binding specificity and degradation properties of MIPs for biosensing applications.
- To ensure the developed MIPs do not compromise CI stability and biosafety.
Main Methods:
- Synthesis of conductive poly(3,4-ethylenedioxythiophene) polystyrenesulfonate-based MIPs using biotin as a surrogate marker.
- Electrochemical impedance spectroscopy (EIS) to assess biotin binding before and after MIP degradation.
- Controlled electrochemical degradation of MIPs to determine optimal conditions for biocompatible clearance.
Main Results:
- MIPs demonstrated specific biotin binding, which was maintained after controlled degradation.
- Electrochemical degradation potential was identified, yielding primarily dissolved monomer molecules for renal clearance.
- Biocompatibility testing confirmed that the polymer and its degradation products are non-cytotoxic (ISO 10993-5).
Conclusions:
- Conductive, biocompatible, and controllably degradable MIPs were successfully developed for biotin detection.
- This technology enables inflammation detection in CIs without compromising device integrity or patient safety.
- The developed MIPs represent a significant advancement for smart CI systems and personalized medicine.
Abstract:
After cochlear implant (CI) insertion, there is a possibility of postoperative inflammation, which may involve proinflammatory markers such as interleukin-6. Detecting this inflammation promptly is crucial for administering anti-inflammatory drugs, if required. One potential method for detecting inflammation is using molecular imprinted polymers (MIPs). These MIPs, which can be deposited on the CI electrode, provide readout employing impedance measurements, a feature already available on the CI circuit. MIPs designed for this purpose should possess biocompatibility, conductivity, and degradability. The degradability is crucial because there is a limitation on the number of electrodes available, and once the inflammation sensor degrades after the acute inflammation period, it should remain usable as a regular electrode. In this work, conductive poly(3,4-ethylenedioxythiophene) polystyrenesulfonate-based MIPs were synthesized against biotin as a surrogate target marker. Specific biotin binding with MIPs was determined before and after degradation using electrochemical impedance spectroscopy (EIS) and compared with the control nonimprinted polymers (NIPs). Subsequently, MIPs were electrochemically degraded by EIS with different potentials, wherein a potential dependence was observed. With decreasing potential, fewer dissolved polymers and more monomer molecules were detected in the solution in which degradation took place. At a potential of 0.205 V a negligible amount of dissolved polymer in addition to the dissolved monomer molecules was measured, which can be defined as the limiting potential. Below this potential, only dissolved monomer molecules are obtained, which enables renal clearance. Biocompatibility testing revealed that both the polymer and the solution with dissolved monomer molecules do not exceed the ISO 10993-5 cytotoxicity threshold. Based on these findings, we have developed conductive, biocompatible, and controllably degradable MIPs capable of detecting biotin. This research work paves the way for the advancement of CIs, where inflammation can be detected using molecular imprinting technology without compromising the stability and biosafety of the product.
