Our research can be divided up into several key themes. Some of the technologies are focused on the detection of harmful chemicals that are a threat to the environment and human health. Others look inside the body for markers or presence of disease. Still others focus on the detection of human-made threats.

Our center focuses on five major research areas:

Molecular electronics

We are interested in charge transfer phenomena in single molecules and work on the forefront of single-molecule and biomolecular electronics.  By advancing scanning probe microscope techniques, we have developed methods to measure electrical transport in a single molecule covalently bonded to two electrodes.  Besides electrical property, our technique enables measurement of mechanical, thermal and chemical properties of a variety of molecules such as alkanes, DNAs, proteins and graphenes. Our current research focuses on a number of key areas: 1) investigating fundamental issues in single-molecule electronics, 2) working towards single-molecule electronic devices, 3) enabling biological and chemical sensing devices based on small numbers of molecules.  

Funding source: NSF, MURI program



Leading Investigators: Drs. Shaopeng 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.



Chemical sensors

Our research bridges the gap between science and real world needs, by transforming new fundamental chemical sensing principles into practical solutions.  We develop low cost, portable, and easy-to-use tools that can empower users with minimal training to perform simple diagnosis and disease management. Our devices can report chemical biomarkers non-invasively, and body exposure to pollutants.

Our efforts focus on the creation of: 1- sensitive and selective chemical sensors, 2- smart sample collection systems, 3- unambiguous calibration methods, 4- robust sensors’ signal processing, and 5- easy-to-use interfaces. We bind these capabilities to smart phones, thereby increasing resources for mobile health. Our team is a multidisciplinary group of enthusiastic engineers, chemists, physicists, and healthcare professionals; our mission is to enable people to take responsibility of their personal health or their loved ones.



Protein microarrays


The illustration shows a protein microarray bitmap image generated using our technology.

Nearly all diagnostics and therapeutics act through proteins, which are the working machines of biology. The normal activities of proteins and their dysfunction in disease have been traditionally investigated one protein at a time. The process, however, will be dramatically accelerated through the use of protein microarrays, which microscopically display thousands of functional proteins.  We are developing technology to mass produce better and less expensive protein microarrays, making them more readily accessible to the broad research and health care communities. Protein microarrays have the greatest prospects to revolutionize molecular diagnostics for early detection, diagnosis, treatment, prognosis and monitoring clinical response. However, protein microarrays have yet to reach their full potential due to difficulties associated with their manufacture.  Currently protein microarrays are manufactured by expressing & purifying thousands of proteins, which are then stored until they are printed; a process with many inherent logistical problems. Furthermore, many proteins are unstable, so these steps must all be maintained at cold temperature.  Thus, there are compelling needs for better and less expensive manufacturing methods for protein microarrays.  We are combining several technologies to develop an innovative method to mass produce faster, better and cheaper protein microarrays based on printing arrays of cDNA templates onto an array of nanowells and expressing proteins in situ, from the templates, in the nanowells.   We have developed technology to rapidly fill the array of nanowells with reagent and seal them into isolated chemical reaction chambers.  By making high-quality protein microarrays more readily assessable, we will help unlock their true potential for research and clinical application.  

This work is supported by Department of Health and Human Services, National Institutes of Health, National Institute of General Medical Sciences, Grant Number: 5R42GM106704-04




Figure 1. Free-standing nanowire transistor bio-probe. A free-standing kinked nanowire transistor probe is positioned in three dimensions to record the intracellular action potential of a beating cardiomyocyte cell.

Dr. Qing and his group focus on the design and preparation of novel nanomaterials with unique structures and characteristics for high performance electronics and biosensing applications. This includes (1) rational synthesis and assembly of 0-D and 1-D metal/semiconductor materials into devices and structures that match the length scales of the cellular and molecule processes key to cell metabolism and communication, (2) studies of the fundamental chemical and physical properties of such materials/structures with the emphasis on pushing beyond the limit of conventional detection of cell activities and molecular interactions, and (3) prototyping bio-probes that can be integrated with live cell network/tissues for in vivo monitoring and stimulation applications. Qing’s recent work highlights novel nanowire-based biosensors interfaced with live cells/cell networks, including development of ultrasmall and multiplexed probes as new tools for fundamental research of extra- and intracellular processes, creating hybrid structures of nanoscale electronics and living cell networks/tissues for bidirectional communication and biomimetic information processing.

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The BB center creates new enabling tools for biomedical and environmental health research, develops wireless personal sensors for mobile health solutions, and explores fundamental phenomena of nature at the single molecule level for next-generation detection technologies.

New plasmonic technologies are invented for label-free imaging and detection of subcellular activities, from protein binding, ion-channel and organelle activities, to single-protein detection in live cells. The technologies show extreme precision in sensing small molecules, as well as providing super resolution optical imaging and image-based stand off detection of human metabolic activities.

To develop pocket-sized wireless sensing devices, we hybridize different sensing platforms, including electrical, electrochemical, mechanical and optical signal transductions. This permits us to achieve results that a single sensor alone cannot deliver.  We use a system-level approach that optimizes devices from sample collection and sensing elements to signal processing and communication to deliver a complete solution to real-world problems. 

From both experimental and theoretical aspects, we are developing techniques to measure the fundamental properties of single molecules, their electronic, mechanical, and thermoelectrical properties, etc, and exploring their application for next-generation detection devices.