In the crowded cellular milieu, biological processes require coordinated intermolecular interactions, conformational changes, and molecular transport that span a wide range of spatial and temporal scales. This complexity requires an integrated, noninvasive, multiscale experimental approach. Here, we develop a multimodal fluorescence microspectroscopy system, integrated on a single platform, to gain information about molecular interactions and their dynamics with high spatio-temporal resolution. To demonstrate the versatility of our experimental approach, we use rhodamine 123-labeled mitochondria in breast cancer cells (Hs578T), verified using differential interference contrast (DIC) and fluorescence (confocal and two-photon) microscopy, as a model system. We develop an assay to convert fluorescence intensity to actual concentrations in intact, individual living cells, which contrasts with conventional biochemical techniques that require cell lysates. In this assay, we employ two-photon fluorescence lifetime imaging microscopy (FLIM) to quantify the fluorescence quantum yield variations found within individual cells. Functionally driven changes in cell environment, molecular conformation, and rotational diffusion are investigated using fluorescence polarization anisotropy imaging. Moreover, we quantify translational diffusion and chemical kinetics of large molecular assemblies using fluorescence correlation spectroscopy. Our integrated approach can be applied to a wide range of molecular and cellular processes, such as receptor-mediated signaling and metabolic activation.
The morphology, as well as the related fracture and mechanical behavior of vinyl ester resins (DVER) of different molecular weights cured with styrene (S) and modified with two different liquid rubbers are presented and discussed. The liquid rubbers are: carboxyl terminated poly(butadiene-co-acrylonitrile) (CTBN), a common toughening agent for epoxy resins, and an almost unreactive rubber with the DVER and S comonomers, and a reactive rubber (vinyl terminated poly(butadiene-co-acrylonitrile), (VTBN). The initial miscibility of the modified systems and the reactivity of the rubber determine the final morphology of the material. This morphology will correspond to a continuous main phase (rich in the DVER-S copolymer) with simple rubber rich inclusions (as in the epoxy-rubber systems) or with inclusions with a complex internal structure, where phase separation occurs as in the low profile modified unsaturated polyester resins. The morphologies developed are strongly dependent on the resin molecular weight as well as on the elastomer added. In spite of the initially higher compatibility of the S-DVER-CTBN system with respect to the S-DVER-VTBN system, the reactivity of the vinyl-ended elastomer leads to a much finer distribution of the elastomeric phase. In particular, the low molecular weight resin cured with S and modified with 10% of CTBN leads to a cocontinuous structure with microvoids that generates a material of low density and poor mechanical and fracture properties. On the other hand, the use of VTBN as additive leads to a more compact morphology, with gradual reduction of the mechanical performance of the modified resins and improved fracture behavior.
Although the use of sugar and sugar derivatives has been documented in polymer research for many years, there are no reports that would utilize these species as polymerization sites of colloidal polymeric particles that, later on, may be released during particle coalescence to form films with surfaces that differentiate protein adsorption. These studies show that, when n-dodecyl-beta-D-maltoside (DDM) is utilized for the synthesis and stabilization of poly[methyl methacrylate-co-(n-butyl acrylate)] (p-MMA/nBA) colloidal particles, upon particle coalescence DDM stratifies near the film-air (F-A) interface. By using attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy and internal reflection infrared imaging (IRIRI), comparative adsorption studies on p-MMA/nBA surfaces exposed to globulin (Glo), fibrinogen (Fib), and bovine serum albumin (BSA) reveal that the presence of DDM selectively inhibits Glo and Fib adsorption, but does not affect BSA. The presence of DDM also enhances the rate of mobility of sodium dioctylsulfosuccinate (SDOSS) resulting from interactions between DDM and SDOSS moieties, and the surface morphologies change as a result of concentration variations of DDM in the colloidal dispersions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.