Enhancing ophthalmic drug delivery by electrochemically induced ion flow with a self-powered contact lens

Various approaches have been conducted for ophthalmic drug delivery to the eye. Intravitreal injections, a traditional invasive method, offer direct drug administration but carry several risks including infections and inflammations, while non-invasive methods like eye drops suffer from poor delivery due to the rapid tear clearance and limited permeability. To overcome these challenges, iontophoresis has been applied to ophthalmic drug delivery. However, conventional iontophoresis systems need to be done with external power source, and they need the counter electrode to be placed on the other part of body, such as forehead, which is inconvenient for user. Here, we developed a self-powered contact lens for iontophoresis, eliminating the need for an external power source. A galvanic cell was fabricated and attached to the lens to generate the current and electric field for iontophoresis by discharging when it was placed on the eye. AgCl served as cathode and Zn was used as anode during the discharge. Riboflavin phosphate in aqueous solution was selected as the model drug and comparative analysis of delivery was done with different designs and materials for both in-vitro and ex-vivo conditions. Cadaver porcine eyes were used for ex-vivo experiments. Riboflavin release was higher with our electrodes than control without applying any electric field. Our approach could reduce the delivery time as well, showing the potential to become a convenient method for various ophthalmic drug deliveries.