Looking beyond biology: glycosaminoglycans as attractive platforms for energy devices and flexible electronics

Over the last few decades, research on glycosaminoglycans (GAGs) has primarily exploited their biological properties, since GAGs play pivotal roles in numerous key biological processes. Consequently, GAGs have attracted the interest of the biomaterial research community, with GAG-related materials finding increasing potential applications in classical areas such as drug delivery, tissue engineering, and wound healing. Notably, among the various reasons for their use is their capacity to conduct charges. Overall, GAGs exhibit conductivity values between 10⁻³ and 10⁰ mS cm⁻¹, comparable to those observed for several biological tissues. This appealing attribute has made GAGs prime candidates for the development of novel materials for bioelectrodes, biosensors, bioinks, electroceuticals, and other devices in the fast-growing fields at the interface between electronics and biology. Moreover, their use as conductive materials has extended beyond the realm of biosciences, with emerging reports of applications of GAGs in fuel cells, batteries, supercapacitors, or flexible electronic devices becoming increasingly common in the last few years. Coincidentally, the first review papers dedicated to the conductive properties of these materials have recently started to appear, providing yet another signal with regard to the growing interest in GAGs. We intend to present here an integrated and comprehensive outlook on the conductive properties of GAGs, both in the solid and solution states, from the initial studies carried out in the 1970s to the very latest developments, thus encompassing more than 40 years of research. Much of this work is rooted in biomaterial applications, making the reference to these applications unavoidable. Special emphasis will be given to the work produced for purposes other than the biomaterials field. We will mention the first attempts at exploring GAGs in energy devices and flexible electronics, and discuss the future of this class of biopolymers. On account of their electrochemical features, distinctive versatility, abundance, low cost, and eco-friendliness, GAGs offer exciting prospects for the development of energy-efficient and sustainable electroactive systems, which only depend on the researchers’ imagination and creativity.