Nanophotonic sensor implants with 3D hybrid periodic-amorphous photonic crystals for wide-angle monitoring of long-term in-vivo intraocular pressure

Abstract

Glaucoma, one of the leading cause of irreversible blindness, is largely caused by an elevated intraocular pressure (IOP). However, current IOP monitoring techniques inherit major disadvantages such as imprecision, no real or long time monitoring, and difficult readout. Here, we report on a highly miniaturized (200 um thick) optomechanical nanophotonic sensor implant for long-term, continuous and on-demand IOP monitoring. This IOP sensor is made of a flexible 3D hybrid photonic crystals (HPC) that functions as a pressure-sensitive optical resonator (0.1 nm/mm Hg) and delivers IOP readings when interrogated with near-infrared light with an average accuracy of 0.56 mm Hg over the range of 0–40 mm Hg. A new fabrication process is developed using colloidal self-assembly leading to a single step formation of hybrid periodic and amorphous layers exploiting the inverse process of a drying "coffee-stain" effect. The HPC results in a wide-angle strong resonance of ±40° ensuring an easy and accurate remote and long readout distance. 8 sensors were mounted inside the anterior chamber in New Zealand white rabbits and provided continuous, accurate measurements of IOP with handheld detector for up to 6 months with no signs of inflammation.