Electrochemically Degraded Dopamine Film for the Determination of Dopamine

Multifunctional Natural and Synthetic Melanin for Bioelectronic Applications: A Review

Emerging material interest in bioelectronic applications has highlighted natural melanin and its derivatives as promising alternatives to conventional synthetic conductors. These materials, traditionally noted for their adhesive, antioxidant, biocompatible, and biodegradable properties, have barely been used as conductors due to their extremely low electrical activities. However, recent studies have demonstrated good conductive properties in melanin materials that promote electronic-ionic hybrid charge transfer, attributed to the formation of an extended conjugated backbone. This review examines the multifunctional properties of melanin materials, focusing on their chemical and electrochemical synthesis and their resulting structure-property-function relationship. The wide range of bioelectronic applications will also be presented to highlight their importance and potential to expand into new design concepts for high-performance electronic functional materials. The review concludes by addressing the current challenges in utilizing melanin for biodegradable bioelectronics, providing a perspective on future developments.

Review of recent advances in analytical techniques for the determination of neurotransmitters

Methods and advances for monitoring neurotransmitters in vivo or for tissue analysis of neurotransmitters over the last five years are reviewed. The review is organized primarily by neurotransmitter type. Transmitter and related compounds may be monitored by either in vivo sampling coupled to analytical methods or implanted sensors. Sampling is primarily performed using microdialysis, but low-flow push-pull perfusion may offer advantages of spatial resolution while minimizing the tissue disruption associated with higher flow rates. Analytical techniques coupled to these sampling methods include liquid chromatography, capillary electrophoresis, enzyme assays, sensors, and mass spectrometry. Methods for the detection of amino acid, monoamine, neuropeptide, acetylcholine, nucleoside, and soluble gas neurotransmitters have been developed and improved upon. Advances in the speed and sensitivity of these methods have enabled improvements in temporal resolution and increased the number of compounds detectable. Similar advances have enabled improved detection at tissue samples, with a substantial emphasis on single cell and other small samples. Sensors provide excellent temporal and spatial resolution for in vivo monitoring. Advances in application to catecholamines, indoleamines, and amino acids have been prominent. Improvements in stability, sensitivity, and selectivity of the sensors have been of paramount interest.