A wide range of conventional immunoassays and emerging biosensors rely on antibodies, which are required to be maintained under tightly regulated temperature (refrigerated) conditions, to preserve their biofunctionality (recognition capability). This stringent requirement necessitates a “cold chain” system during transportation and storage, which is usually impractical in resource-limited settings. Here, we introduce two types of materials, zeolitic imidazolate framework-8 (ZIF-8), a metal-organic framework (MOF), and silk fibroin, extracted from silk cocoon, to form protective coatings to preserve the antibody recognition capability on biochips under ambient and elevated temperatures. Formation of these protective coatings is easy, and a simple water rinsing step can restore the biofunctionality of the coated biochip, thereby making it highly convenient for use in point-of-care and resource-limited settings. A plasmonic nanobiosensor is employed as a transduction platform for monitoring the formation and removal of the protective coatings and to quantify the biopreservation ability of these coatings under various extreme storage conditions. We believe this energy-efficient and environmentally-friendly approach eliminates the needs for cold chain and temperature-controlled storage/shipping of diagnostic reagents and materials, thereby extending the capability of antibody-based biosensors to various resource-limited environments. More broadly, these protective coatings are expected to play a powerful role in the realization of ultrastable biodiagnostics and therapeutics. We will also present a novel class of plasmonic biosensors that rely on artificial antibodies or peptide recognition elements with excellent temperature and chemical stability. These multi-pronged approaches overcome the poor stability of existing plasmonic biosensors or other types of antibody-based biosensors and take them closer to real-world applications in resource-limited settings.

© 2017 Optical Society of America

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