A Label-Free Optical Biosensor Built on a Low-Cost Polymer Platform

Planar integrated optical biosensors are becoming more and more important as they facilitate label-free and real-time monitoring with high sensitivity. In this paper, the systematic work on the development of this kind of optical biosensor built on a novel polymer platform named PSQ-Ls will be presented. The material itself is of very low cost, and the optical devices with high performances are fabricated through a simple UV-based soft imprint lithography technique. Especially for ring resonator, Q value as high as 5 × 10⁴ and 2.7 × 10⁴ are achieved in air and water condition. These optical chips are functionalized efficiently with protein A molecules through physical immobilization, after careful investigation of the physicochemical and chemical properties of their surface. Both bulk sensing and surface sensing are performed. The proposed optical biosensor exhibits good response not only to its surrounding environment´s change but also to the small amount of targeted molecules appearing in the buffered solution, which is human-IgG in our study.