Probing the interaction at nano-bio interface using synchrotron radiation-based analytical techniques

Understanding the interactions of nanomaterials(NMs) with biomolecules, organelles, cells, and organic tissues at the nano-bio interface can offer important information for their uptake, distribution, translocation, metabolism and degradation in vitro and in vivo, which can help to precisely tune and design "smart" NMs for biomedical applications. However, probing the interactions at the nano-bio interface, which generally requires dedicated analytical methods and tools, is remarkably complicated due to the dynamically changed nature of the nano-bio interface. Because of the advantages of high spatial resolution, high sensitivity, excellent accuracy, low matrix effects and non-destructiveness, synchrotron radiation(SR)-based analytical techniques have become extremely valuable tools. Herein, we present a comprehensive overview of SR-based techniques for the visualized study of NMs at cellular and subcellular interfaces and their transformation in vitro; the exploration of biodistribution, translocation, metabolism and degradation of NMs in vivo; and clarification of the molecular mechanisms of NMs' reactions with biomolecules. Rapid development of advanced light source means that in situ, real-time analysis of NMs at the nano-bio interface will be achieved.

Toward the Next Frontiers of Vibrational Bioimaging

Chemical imaging based on vibrational contrasts can extract molecular information entangled in complex biological systems.To this end,nonlinear Raman scattering microscopy,midinfrared photothermal(MIP)microscopy,and atomic force microscopy(AFM)-based force-detected photothermal microscopies are emerging with better chemical sensitivity,molecular speciffcity,and spatial resolution than conventional vibrational methods.Their utilization in bioimaging applications has provided biological knowledge in unprecedented detail.This Perspective outlines key methodological developments,bioimaging applications,and recent technical innovations of the three techniques.Representative biological demonstrations are also highlighted to exemplify the unique advantages of obtaining vibrational contrasts.With years of effort,these three methods compose an expanding vibrational bioimaging toolbox to tackle speciffc bioimaging needs,beneffting many biological investigations with rich information in both label-free and labeling manners.Each technique will be discussed and compared in the outlook,leading to possible future directions to accommodate growing needs in vibrational bioimaging.