Green photonic biosensing: Approaching sustainability in point-of-care diagnostics

Structural colour biosensors have emerged due to the ability to mimic photonic crystals and their stimuliresponsive properties. Recently, global awareness of device sustainability has led point-of-care (POC) testing to focus on the use of natural materials based on their biocompatible and biodegradable properties. In this review, structural colours in nature are briefly overviewed as the basis for their use in biosensors. In particular, the integration of natural biopolymers into novel photonic sensing devices for the detection and quantification of disease biomarkers is reviewed in detail. The discussion is extended beyond mimicry to natural nanoarchitectures as elements of biosensors. Finally, the integration of bioinspired photonic materials into microfluidics for smart and low-cost devices is addressed. This review contributes to show how photonic crystal-based sensing devices can evolve in the context of sustainable POC diagnostics and have an impact on the future of personalised medicine pursuing nature-inspired strategies.