Nanoparticle Dopants for Conducting Polymers
Electric current is crucial to nervous system function, cell communication, and muscle contraction. Biologically-interfacing electrodes are fundamental components of implanted medical devices such as biochemical sensors, drug delivery platforms, and cardiac and neural stimulating/recording electrodes in humans. Currently, the development of next-generation devices has been limited by material concerns; impedance and charge injection limits are inversely proportional to the surface area of a device, a fact that is at odds with the drive to miniaturize such devices in order to minimize invasiveness and increase the density of information flow.
Description
By modifying the device surface with conducting polymers such as a PEDOT film doped with sulfonated silica nanoparticles, which boast low interfacial impedance, high charge injection, and excellent stability under repetitive stimulation, researchers have enabled safe and efficient stimulation with less power and higher signal-to-noise ratio. Silica nanoparticle dopants are highly versatile and can be tuned to enhance different aspects of conducting polymers. Introducing nanopores as drug carriers allows the load and release of a broad range of drug molecules via electrical control. The nanoparticles demonstrate an increase in drug load, releasing up to 16.7x the usual, and expand the range of drug candidates to include both cationic and electroactive compounds compared to conventional conducting polymers without dopants. Perhaps most importantly, doping a conductive polymer coating with silica nanoparticles maintains the impressive electrochemical properties of PEDOT films, creating countless options to produce composite film and nanoparticle materials for enhanced electrical stimulation, neural recording, chemical sensing, tissue engineering and on-demand drug delivery.Applications
· Doping conductive polymers with engineered nanoparticles· Chemical sensing
· Neural recording
· Tissue engineering
· Drug delivery
Advantages
· Lower interfacial impedance even at small sizes· High charge injection
· Excellent stability
· Up to 16.7x increase in drug load over conventional options
· Expanded ability to accommodate a variety of drug candidates, including cationic and electroactive compounds