Biopolymer based artificial synapses enable linear conductance tuning and low-power for neuromorphic computing.

Neuromorphic computing is considered a promising method for resolving the traditional von Neumann bottleneck. Natural biomaterial-based artificial synapses are popular units for constructing neuromorphic computing systems while suffering from poor linearity and limited conduction states. In this work, a AgNO3 doped iota-carrageenan (ι-car) based memristor is proposed to resolve the non-linear limitation. The memristor presents linear conductance tuning with a higher endurance (∼104), more enriched conduction states (>2000), and much lower power consumption (∼3.6 µW) than previously reported biomaterial-based analog memristors. AgNO3 is doped to ι-car to suppress the formation of Ag filaments, thereby eliminating uneven Joule heating. Using deep learning of hand-written digits as an application, a doping-enhanced recognition accuracy (93.8%) is achieved, close to that of an ideal synaptic device (95.7%). This work verifies the feasibility of using biopolymers for future high-performance computational and wearable/implantable electronic applications.

Bioresorbable photonic devices for the spectroscopic characterization of physiological status and neural activity.

Capabilities in real-time monitoring of internal physiological processes could inform pharmacological drug-delivery schedules, surgical intervention procedures and the management of recovery and rehabilitation. Current methods rely on external imaging techniques or implantable sensors, without the ability to provide continuous information over clinically relevant timescales, and/or with requirements in surgical procedures with associated costs and risks. Here, we describe injectable classes of photonic devices, made entirely of materials that naturally resorb and undergo clearance from the body after a controlled operational lifetime, for the spectroscopic characterization of targeted tissues and biofluids. As an example application, we show that the devices can be used for the continuous monitoring of cerebral temperature, oxygenation and neural activity in freely moving mice. These types of devices should prove useful in fundamental studies of disease pathology, in neuroscience research, in surgical procedures and in monitoring of recovery from injury or illness.