New Detection Technologies

Spatially resolved protein binding kinetics of a single cell by surface plasmon resonance microscopy.

Leading Investigators: Drs. Nongjian Tao, Shaopeng Wang, Wei Wang and Xiaonan Shan

The Biosensors group works on developing label-free imaging tools and methods, and applying them for biomarker research, drug discovery and disease diagnosis. Our current research is focused on three major directions: (1) In-situ imaging and measuring single cell and subcellular activities in live cells, including membrane protein binding kinetics, cellular signal pathway dynamics, ion channel events and organelle activities; (2) detecting and imaging single small molecules, viruses and bacteria; (3) developing super resolution plasmonic-based imaging platform; (4) measuring and imaging electrochemical properties of nanomaterials.

Core technology: We invented plasmonic-based electrochemical impedance microscopy (P-EIM), which can detect electrochemical impedance signals optically.

In P-EIM, we take advantage of the high sensitivity of surface plasmonic resonance (SPR) to detect surface impedance and electrochemical signals with high spatial and temporal resolution, which cannot be realized by other electrochemical methods. Furthermore, the P-EIM system can be built on standard inverted fluorescence microscopy, which enables in-situ multifunctional imaging of the sample and can simultaneously obtain transmitted, fluorescence, SPR and P-EIM images of target samples. This feature allows us to combine the advantages of both labeled and label-free imaging in one system. Beside P-EIM, we are also interested in other label-free detection technologies.

Funding sources: NIH, NSF, W.M. Keck Foundation, The Gordon and Betty Moore Foundation , Virginia G. Piper Charitable Trust, Amgen Inc.

Figure 1. Principle of P-EIM microscopy: (A) Schematic of P-EIM imaging principle, and (B) optical, SPR and P-EIM images of protein microarray, nanoparticles and a mammalian cell..