Bio-organic collagen-graphene nanofiber synaptic device emulating neuroplasticity and spike-timing-dependent plasticity

초록

Collagen is a biocompatible and biodegradable biopolymer with potential applications in bioelectronics; however, its poor electrical conductivity limits its use in electronic devices. To overcome this, we have composited the collagen with highly conducting 2D graphene and synthesized one-dimensional (1D) collagen-graphene nanofibers (Col-Gr NFs) by the electrospinning technique. These 1D NFs were utilized to emulate comprehensive neuroplasticity for neuromorphic computing applications, owing to their structural and functional similarities to biological neurons and synapses. The Ag/Col-Gr NFs/FTO device shows good bipolar resistive switching within +/- 1 V. Moreover, the Ag/Col-Gr NFs/FTO device shows excellent cycle stability (15,000 cycles) and memory retention (30,000 s) by switching between two memory states. The charge-flux analysis confirmed the device's non-ideal memristive behaviour. The switching variability was assessed using different statistical techniques. The device emulates key synaptic behaviours, including potentiation, depression, excitatory and inhibitory post-synaptic currents (EPSC/IPSC), paired-pulse facilitation and depression (PPF/PPD), and two types of spike-timing-dependent plasticity (STDP) rules. Importantly, the Ag/Col-Gr NFs/FTO device exhibited complete degradation in aqueous conditions, confirming its physically transient nature. This work demonstrates the promising potential of Col-Gr composite NFs as a novel material for sustainable artificial synaptic devices.

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