Abstract:

Raman microspectroscopy is a label-free non-destructive experimental technique that does not require complex sample preparation, adaptable for in-situ measurements, delivers high molecular specificity, offers a rapid route to assess the molecular composition of individual live microorganisms (e.g. bacteria, fungi, archaea, protists etc) and map their chemical environment on nanoscale, all on timescale of seconds. Hence, it has been widely used for identification of bacterial species, mutants and physiological states in microbiology. Despite informative potential, significant challenges arise from the relatively low signal-to-nose ratio in small cells and signal overlap of multiple Raman-active cellular components, making it difficult to extract cell-specific information. Approaches used to overcome some of these challenges, such as principal component analysis may capture broad differences across the entire spectrum but may not be able to pinpoint changes in a particular cellular component. To address this, we demonstrate that using metal (or metal coated) substrates together with deconvolution of Raman spectra based on Bayesian statistical analysis can yield significant improvements in data interpretation and in understanding cell biology. We also suggest future directions in Raman data collection and analysis of cells on nanoscale.

BIO:

Dr. Sapelkin received his PhD in Physics from the Department of Chemistry and Physics, De Montfort University, Leicester, UK (1998) and before that he obtained MSc in Applied Physics and Mathematics from Moscow Institute of Physics and Technology, Moscow, Russia (1994). Currently, he is a Senior Lecturer, Queen Mary University of London, UK. In his research activities he is leading several distinct cross-disciplinary threads with an overarching theme of structure, properties and applications of nanoscale and disordered matter and interaction with biological matter. His international reputation is reflected in invitations to serve as an Editorial Board member at Scientific Reports (SpringerNature) and Nanomaterials (MDPI) journals as well as by serving as an international reviewer for the Research Grants Council (RGC) of Hong Kong. Over the last 5 years he published 46 papers, developed, and sustained several collaborations (CEMES and Toulouse University, Toulouse, France, BMSTU, Moscow, Russia; SSU, Saratov, Russia; Imperia College; UCL), maintained a successful research group and graduated 10 PhD students.