title: Silk-Encapsulated Plasmonic Biochips with Enhanced Thermal Stability.
abstract: Because of their high sensitivity, cost-efficiency, and great potential as point-of-care biodiagnostic devices, plasmonic biosensors based on localized surface plasmon resonance have gained immense attention. However, most plasmonic biosensors and conventional bioassays rely on natural antibodies, which are susceptible to elevated temperatures and nonaqueous media. Hence, an expensive and cumbersome "cold chain" system is necessary to preserve the labile antibodies by maintaining optimal cold temperatures during transport, storage, and handling. Herein, we introduce a facile approach to preserve the antibody activity on a biosensor surface even at elevated temperatures. We show that silk fibroin film could be used as a protective layer to preserve the activity of a model antibody (Rabbit IgG) and cardiac troponin antibody at both room temperature and 40 °C over several days. Furthermore, a simple aqueous rinsing process restores the biofunctionality of the biosensor. This energy-efficient and environmentally friendly method represents a novel approach to eliminate the cold chain and temperature-controlled packing of diagnostic reagents and materials, thereby extending the capability of antibody-based biosensors to different resource-limited circumstances such as developing countries, an ambulance, an intensive care unit emergency room, and battlefield.
authors.forename: Congzhou
authors.initials: C
authors.lastname: Wang
authors.forename: Jingyi
authors.initials: J
authors.lastname: Luan
authors.forename: Sirimuvva
authors.initials: S
authors.lastname: Tadepalli
authors.forename: Keng-Ku
authors.initials: KK
authors.lastname: Liu
authors.forename: Jeremiah J
authors.initials: JJ
authors.lastname: Morrissey
authors.affiliation: The Center for Clinical Pharmacology, St. Louis College of Pharmacy and Washington University School of Medicine , St. Louis, Missouri 63110, United States.
authors.forename: Evan D
authors.initials: ED
authors.lastname: Kharasch
authors.affiliation: 711th Human Performance Wing, Wright-Patterson Air Force Base , Dayton, Ohio 45433, United States.
authors.forename: Rajesh R
authors.initials: RR
authors.lastname: Naik
authors.forename: Srikanth
authors.initials: S
authors.lastname: Singamaneni
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D006046:Gold; D043942:Nanotubes; D011817:Rabbits; D047011:Silk / Q000737:chemistry*; D020349:Surface Plasmon Resonance; D013696:Temperature
chemical_list: D047011:Silk; D006046:Gold
keywords: biopreservation; gold nanorods; localized surface plasmon resonance; plasmonic biosensor; silk