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  • Shibdas Banerjee (Monon)

    Shibdas Banerjee (Monon)

    Postdoctoral Research Fellow, Chemistry

    Current Research and Scholarly Interests Research Area 1:
    Diagnosis of Cancer by Metabolic Signatures Using Desorption Electrospray Ionization Mass Spectrometric Imaging

    The important hallmark feature of tumorigenesis is the global shift in metabolism imparted by the malfunctioning of oncogenes. Oncogenes are known to regulate the key genes involved in the lipid metabolism. This phenomenon suggests that in situ analyses of cancerous cell/tissue metabolites (lipids) could reveal potential biomarkers or molecular targets to detect, diagnose and prognosticate cancer. Thus, the ability to easily record the metabolic signature of biopsy specimens (within minutes of biopsy) would eventually develop a rapid, quantitative and accurate pathology method for early detection and diagnosis of clinically relevant diseases including cancer.
    Recently, an innovative form of an ambient mass spectrometry (highly sensitive analytical approach) called desorption electrospray ionization mass spectrometry (DESI-MS) has been developed to provide the microscopic examination of cancer metabolism in tissues. DESI-MS has been demonstrated to construct ion images for the visualization (distribution) of molecules/metabolites on the histological section. It appears from the our preliminary studies that imaging the spatial distribution of different phospholipids and cholesterol sulfates in different organs (lipid profiles in tissues) have significance in disease diagnosis including provision of information on tumor margins to guide doctors during surgical removal of the corresponding tumor.

    Research Area 2:
    Microdroplet Chemistry: From Conducting Chemical Transformation to Probing the Reaction Mechanism

    The charged microdroplets, generated by the electrospray (ES) process, have been shown to ionize intact chemical species followed by their transfer to the gas phase. This ionization technique is now being routinely used as a standard soft-ionization process for different molecules including proteins, lipids, carbohydrates, and other small organic or organometallic compounds for their mass spectrometric analysis. In last two decades, several groups have extensively worked to understand the nature of the ES droplet and the mechanism that leads to the production of gas-phase ions on the millisecond timescale. Taking the advantage of special charged environments of ES droplets, and the short timescale (ms) of their evolution, we are transcending the traditional applications of electrospray process from mass spectrometry to synthetic and mechanistic organic chemistry. There are several reactions, which are hard to achieve in conventional bulk-phase, and those too take long time (e.g., from hours to days) to yield significant amount of products. Our preliminary studies on such model reactions in microdroplets show the potential application of the ES process to induce acid/base catalyzed organic transformation on the millisecond timescale in limited and confined spaces (microdroplets) under charged environments. We found marked acceleration of those reaction rates even by a factor of a million when carried out in microdroplets. The mechanism is not presently established but droplet evaporation and droplet confinement of reagents appear to be two important factors among others. We suggest that this ?microdroplet chemistry? could be a remarkable alternative to accelerate slow and difficult reactions, and in conjunction with mass spectrometry, it may provide a new arena to study chemical and biochemical reactions in a confined environment. This ?microdroplet chemistry? is still in its infancy and heightens our interests to apply this method to organic syntheses on the preparative scale.
    Our studies also underscored the impressive capabilities of the ?microdroplet chemistry? to capture transient intermediates in solution-phase catalytic cycles of complex reactions to investigate the reaction mechanism.

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