Pressure-Triggered Microfluidic Contact Lens for Ocular Drug Delivery

Microfluidic technology has been used for precise drug delivery for many years, but microfluidic wearable devices have mostly been used for skin drug delivery. The application of eye drops is currently one of the most common ways to treat eye diseases. However, due to their low corneal bioavailability and short residence time in tears, topical eye drops must be applied multiple times a day. Contact lenses, as a wearable device for the eye, are a good platform for drug delivery. In this paper, we propose a type of microfluidic contact lens that integrates a microchannel and a micropump and uses a pressure source to trigger the release of a drug. Here, a flat microfluidic chip component is first fabricated by photolithography and then cast into a curved surface by secondary thermosetting. Through experiments, the outlet check valve opening pressure and liquid flow test were studied to prove that the liquid release is controllable. In addition, the microfluidic contact lens has good flexibility, light transmittance, and biocompatibility. Finally, we demonstrate through fluorescence experiments that the microfluidic contact lens can be loaded with different types of drugs in different regions. In general, liquid exchange between the eye and the contact lens can be realized through the mechanical action of blinking without using electronic components, meaning more safety and stability. The mechanical characteristics of a blink can be artificially regulated to a large extent; thus, it is also possible to achieve specific, personalized medicine.