Lipid droplets as endogenous intracellular microlenses

Using a single biological element as a photonic component with well-defined features has become a new intriguing paradigm in biophotonics. Here we show that endogenous lipid droplets in the mature adipose cells can behave as fully biocompatible microlenses to strengthen the ability of microscopic imaging as well as detecting intra- and extracellular signals. By the assistance of biolenses made of the lipid droplets, enhanced fluorescence imaging of cytoskeleton, lysosomes, and adenoviruses has been achieved. At the same time, we demonstrated that the required excitation power can be reduced by up to 73%. The lipidic microlenses are finely manipulated by optical tweezers in order to address targets and perform their real-time imaging inside the cells. An efficient detecting of fluorescence signal of cancer cells in extracellular fluid was accomplished due to the focusing effect of incident light by the lipid droplets. The lipid droplets acting as endogenous intracellular microlenses open the intriguing route for a multifunctional biocompatible optics tool for biosensing, endoscopic imaging, and single-cell diagnosis.

Determinants of cell–material crosstalk at the interface: towards engineering of cell instructive materials

The development of novel biomaterials able to control cell activities and direct their fate is warranted for engineering functional biological tissues, advanced cell culture systems, single-cell diagnosis as well as for cell sorting and differentiation. It is well established that crosstalk at the cell–material interface occurs and this has a profound influence on cell behaviour. However, the complete deciphering of the cell–material communication code is still far away. A variety of material surface properties have been reported to affect the strength and the nature of the cell–material interactions, including biological cues, topography and mechanical properties. Novel experimental evidence bears out the hypothesis that these three different signals participate in the same material–cytoskeleton crosstalk pathway via adhesion plaque formation dynamics. In this review, we present the relevant findings on material-induced cell response along with the description of cell behaviour when exposed to arrays of signals—biochemical, topographical and mechanical. Finally, with the aid of literature data, we attempt to draw unifying elements of the material–cytoskeleton–cell fate chain.