Rapid Regulation of Local Temperature and Transient Receptor Potential Vanilloid 1 Ion Channels with Wide-Field Plasmonic Thermal Microscopy

Abstract

Plasmonic absorption of light can create significant local heat and has become a promising tool for rapid temperature regulation in diverse fields, from biomedical technology to optoelectronics. Current plasmonic heating usually relies on specially designed nanomaterials randomly distributed in the space and barely provides uniform temperature regulation in a wide field. Herein, we report a rapid temperature regulation strategy on a plain gold-coated glass slip using a plasmonic scattering microscopy, which can be referred to as wide-field plasmonic thermal microscopy (W-PTM). We calibrated the W-PTM by monitoring the phase transition of the temperature-sensitive polymer solutions, showing that it can provide a temperature regulation range of 33–80 °C. Moreover, the W-PTM provides imaging capability, thus allowing the statistical analysis of the phase-transitioned polymeric nanoparticles. Finally, we demonstrated that W-PTM can be used for noninvasive and local regulation of the transient receptor potential vanilloid 1 (TRPV1) ion channels in the living cells, which can be monitored by simultaneous fluorescence imaging of the calcium influx. With the nondestructive local temperature-regulating and concurrent fluorescence imaging capability, we anticipate that W-PTM can be a powerful tool to study cellular activities associated with cellular membrane temperature changes.

Label-free Single-molecule Immunoassay

“…Increasing FOV may also affect the performance of LFSMimmunoassay by lowering camera frame rate and temporal resolution, such that less information could be collected in the binding duration. A more powerful light source is also needed to enable single-molecule sensitivity in larger FOV and the resultant heating effect would affect the performance of the assay as well 33 . Fortunately, imaging technologies powered by machine learning could possibly enable the detection of IgG antibody at lower exposure time, allowing larger FOV imaging with higher frame rates 34 .…”

Surface Plasmon Resonance Biosensors: A Review of Molecular Imaging with High Spatial Resolution

“…For example, an electric field can be applied onto the gold surface, and the analyte movement forced by the electric field can be monitored via SPRi with high precision in the vertical direction owing to the exponential decaying properties of surface plasmon waves, thus allowing for quantitative analysis of analyte electric properties, such as charge and mobility [122]. SPRi can also be combined with fluorescence imaging techniques, while SPRi can track the variations in cellular membranes with high temporal resolution, and fluorescence imaging can provide additional information, such as calcium ion concentrations inside the cells [123]. These approaches demonstrate that SPRi is a great platform for a combination of multiple approaches for multi-parameter analysis to understand biological processes from different aspects.…”

Label-Free Optical Imaging of Nanoscale Single Entities

“…In addition, the practical maximum illumination power density of PSM is limited by the light induced heating effect on the gold surface. 64 Similar to SPRM, the near field evanescent illumination makes the PSM surface sensitive, which is immune to background noise in the solution phase, and could help to detect the orientation of bound molecules. PSM can quantify single protein binding kinetics by digital counting of individual protein interactions 22 and obtain heterogeneous protein behaviors.…”

“…However, the longer wavelength light that PSM needs to generate plasmonic resonance (e.g., ∼660 nm) produces a less scattered signal from the nanoscale objects compared to iSCAT or ESM that can use a shorter wavelength light (e.g., ∼450 nm), which reduces the benefit of plasmonic enhancement down to ∼5 fold. In addition, the practical maximum illumination power density of PSM is limited by the light induced heating effect on the gold surface . Similar to SPRM, the near field evanescent illumination makes the PSM surface sensitive, which is immune to background noise in the solution phase, and could help to detect the orientation of bound molecules.…”