Indirect Nanoplasmonic Sensing Platform for Monitoring Temperature-Dependent Protein Adsorption

• Published in: Analytical chemistry (Washington) Vol. 89; no. 23; pp. 12976 - 12983
• Main Authors: Jackman, Joshua A, Ferhan, Abdul Rahim, Yoon, Bo Kyeong, Park, Jae Hyeon, Zhdanov, Vladimir P, Cho, Nam-Joon
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 05.12.2017
• Subjects: Adsorption; Biopolymer denaturation; Bovine serum albumin; Chemistry; Circular dichroism; Detection; Dichroism; Gold; Kinetics; Light scattering; Molecules; Monitoring; Monomers; Photon correlation spectroscopy; Protein adsorption; Protein arrays; Protein denaturation; Proteins; Sensitivity analysis; Sensors; Serum albumin; Silica; Silicon dioxide; Spectroscopy; Stability analysis; Surface chemistry; Surface plasmon resonance; Surface stability; Temperature effects
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/acs.analchem.7b03921

The development of highly surface-sensitive measurement approaches to monitor protein adsorption across different temperatures would advance understanding of how thermally activated processes contribute to the denaturation of adsorbed proteins. Herein, we established an indirect nanoplasmonic sensing approach to monitor the temperature-dependent adsorption and denaturation of bovine serum albumin (BSA) protein onto a silica-coated array of plasmonic gold nanodisks. A theoretical model was developed to explain how the denaturation of an individual, adsorbed protein molecule influences the localized surface plasmon resonance (LSPR) measurement response and provided an analytical framework to estimate the effect of temperature-dependent protein denaturation on the corresponding adsorption kinetics. The sensing performance of this measurement platform was also characterized across the tested range of temperatures. With increasing temperature (up to 50 °C), it was observed that adsorbed proteins undergo greater denaturation. Circular dichroism spectroscopy and dynamic light scattering experiments verified that individual BSA monomers in bulk solution had increasingly lower conformational stability at higher temperatures within this range, which correlated with the extent of denaturation in the adsorbed state. At higher temperatures, distinct kinetic profiles arising from multilayer/aggregate formation on the sensor surface were also detected. Taken together, our findings identify that the high surface sensitivity and temperature stability of LSPR sensors make them broadly useful analytical tools for monitoring thermally activated biomacromolecular interaction processes.