A fully biocompatible poly(ethylene glycol)–gold plasmonic crystal for optical sensing

• Novel, scalable, cost-effective fabrication to generate a biocompatible device.
• The use of PEG and gold to demonstrate a fully biocompatible plasmonic device.
• Useful fabrication to integrate plasmonic structures to the close-packed PEG nanospheres.

A significant challenge in nano and biophotonics is to demonstrate fully biocompatible nano-optics devices that can perform biofunctions in vivo. Here we present a scalable, cost-effective, and large-area nanofabrication method for creating a quasi-3D plasmonic crystal using poly(ethylene glycol) (PEG) and gold (Au), both biocompatible materials. The plasmonic crystal was prepared by depositing an Au layer on the upper hemisphere of the replicated PEG nanospheres array. Additionally we demonstrated that the fabricated plasmonic crystal can behave as a label-free glucose sensor with sensitivity and figure-of-merit values comparable to other plasmonic crystal based sensors.