The growing demand for sustainable, biocompatible, and multifunctional sensing materials has intensified interest in melanin and its derivatives, including melanin-inspired polymers and composites. Melanin is a naturally occurring biopolymer whose intricate structure and diverse chemical composition give rise to a remarkable combination of optical, electrical, and chemical properties. Key physicochemical characteristics, such as broadband optical absorption, hydration-dependent conductivity, redox activity, and metal ion coordination, are closely linked to melanin’s signal transduction capabilities and underpin its relevance in sensing applications. Recent advances in melanin-based sensing technologies encompass pH, humidity, chemical, biological, and optical platforms, with particular emphasis on hybrid systems incorporating graphene, silicon, or nanomaterials, and printable or wearable device architectures. These developments have enabled enhanced performance and broadened potential application fields. However, persistent challenges, including intrinsic heterogeneity, limited selectivity, relatively low electrical conductivity, and poor long-term operational stability, still limit practical implementation. Emerging molecular engineering and advanced fabrication strategies are being developed to address these limitations. Together, these findings position melanin as a versatile, eco-compatible, and functionally rich material, with a significant potential to underpin the next generation of sustainable sensing technologies.
Cassera et al. (Tue,) studied this question.