Single Cell Biology
Nanoelectrochemistry can examine a vast array of cellular functions, yet achieving the specificity, spatiotemporal resolution, and sensitivity needed to do so is not currently possible. Such measurements will enhance understanding of biology at the most fundamental level and create a rich new field of science. In addition to quantifying metabolism, our work may reveal single mitochondrion activity, detect metabolic changes due to DNA damage, and quantify chemical gradients with nanometer spatial resolution. The study of single cells promises to expose heterogeneities that cannot be observed when measuring many cells or tissue. Single cell genomics and transcriptomics take advantage of robust strategies to amplify DNA and RNA. Small molecule metabolites that make up the metabolome (i.e., glucose, lactate, fumarate, et al.) are incredibly difficult to quantify in a single cell because of low concentrations and the absence of amplification strategies. Mass spectrometric techniques suffer from low signal-to-noise and require that the cell be destroyed to make a measurement. Fluorescent protein biosensors have been developed for metabolites; however, these biosensors are not easily generalizable and require laser irradiation. We are developing nanoscience solutions to elucidate undiscovered dynamic changes, such as in a cell’s life cycle, differentiation of a stem cell, or real-time imaging of carcinogenesis.
Within only a few seconds, we can image several fluorescently-tagged species. Pictured here for proof-of-concept are four polystyrene beads each labeled with a different fluorophore.
Our lab is interested in making highly quantitative measurements inside single, living cells. This requires development of specialized microscopy tools, specifically those that have white light laser capabilities without the expense of white light lasers.
This SEM micrograph of a nanoelectrode shows the sharp, pointy tip after pulling with a laser-puller. Sharp electrodes are able to penetrate a cell and make sensitive measurements within a cell.
While imaging cells is commonplace in most cell biology experiments, the effect of wavelength and intensity of light on cellular metabolism is still an open question.