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Biology subjects

ZHANG, P.

Publications and source records attributed to ZHANG, P..

3 recordsLinked to original sources

Rapid Regulation of Local Temperature and TRPV1 Ion Channels with Wide-Field Plasmonic Thermal Microscopy

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 hardly provides uniform temperature regulation in a wide field. Herein we report a rapid temperature regulation strategy on a plain gold-coated glass slip using the 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 {degrees}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 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.

bioengineering↗

Multiplexed protein detection and parallel binding kinetics analysis with label-free digital single-molecule counting

Multiplexed protein detection is critical for improving the drug and biomarkers screening efficiency. Here we show that multiplexed protein detection and parallel protein interaction analysis can be realized by evanescent scattering microscopy with label-free digital single-molecule counting. We implemented an automatic single-molecule counting strategy with high temporal resolution to precisely determine the binding time, which improves the counting efficiency and accuracy. We show that digital single-molecule counting can recognize proteins with different molecular weights, thus making it possible to monitor the protein binding processes in the solution by real time tracking the numbers of free and bound proteins landing on the sensor surface. Furthermore, we show that this strategy can simultaneously analyze the kinetics of two different protein interaction processes on the surface and in the solution. This work may pave a way to investigate complicated protein interactions, such as the competition of biomarker-antibody binding in biofluid with biomarker-protein binding on the cellular membrane.

biochemistry↗

Single-Objective Evanescent Scattering Microscopy for Imaging Single Proteins and Binding Kinetics

Plasmonic scattering microscopy has advanced the evanescent detection approaches by offering wide-field single-molecule imaging capability. However, two limitations prevent the broader application of plasmonic single-molecule imaging. One is the heating effect accompanying the plasmonic enhancement, and the other is the complicated system structure resulting from the two-objective optical arrangement. Here, we report single-objective evanescent scattering microscopy. The evanescent field is created by total internal reflection instead of the surface plasmon resonance on the gold film. As a result, the sensing substrate without gold film produces little heat, and allows excitation and observation using one objective. In addition, this system enables quantification of protein binding kinetics by simultaneously counting the binding of individual molecules and recording their binding sites with nanometer precision, providing a digital method to measure binding kinetics with high spatiotemporal resolution. This work may pave a road for label-free single protein analysis in conventional microscopy. TeaserLabel-free single-molecule imaging on a total internal reflection fluorescence objective.

biophysics↗