Search

Due to their hydrophilic, biocompatible, and highly tunable nature, hydrogel materials have attracted strong interest in the recent years for numerous biotechnological applications. In particular, their solution-like environment and non-fouling nature in complex biological samples render hydrogels as ideal substrates for biosensing applications. Hydrogel coatings, and later, gel dot surface microarrays, were successfully used in sensitive nucleic acid assays and immunoassays. More recently, new microfabrication techniques for synthesizing encoded particles from hydrogel materials have enabled the development of hydrogel-based suspension arrays. Lithography processes and droplet-based microfluidic techniques enable generation of libraries of particles with unique spectral or graphical codes, for multiplexed sensing in biological samples. In this review, we discuss the key questions arising when designing hydrogel particles dedicated to biosensing. How can the hydrogel material be engineered in order to tune its properties and immobilize bioprobes inside? What are the strategies to fabricate and encode gel particles, and how can particles be processed and decoded after the assay? Finally, we review the bioassays reported so far in the literature that have used hydrogel particle arrays and give an outlook of further developments of the field. Keywords: Hydrogel; Biosensor; Microparticle; Multiplex assay, Novartis Institutes of Biomedical Research (Presidential Fellowship), Novartis Institutes of Biomedical Research (Education Office), National Cancer Institute (U.S.) (Grant 5R21CA177393-02), National Science Foundation (U.S.) (Grant CMMI-1120724), Institute for Collaborative Biotechnologies (Grant W911NF-09-0001), United States. Army Research Office

High-throughput fabrication of graphically encoded hydrogel microparticles is achieved by combining flow contact lithography in a multichannel microfluidic device and a high capacity 25 mm LED UV source. Production rates of chemically homogeneous particles are improved by two orders of magnitude. Additionally, the custom-built contact lithography instrument provides an affordable solution for patterning complex microstructures on surfaces., Novartis Institutes of Biomedical Research. Education Office, National Science Foundation (U.S.) (Grants CMMI-1120724 and DMR-1006147), United States. Army Research Office (Institute for Collaborative Biotechnologies. Grant W911NF-09-0001)