Tertiary structure changes in albumin upon surface adsorption observed via fourier transform infrared spectroscopy.

A nondestructive Fourier transform infrared (FTIR) spectroscopy assay, amenable to exploring a wide range of proteins and polymers, is used to measure changes in the tertiary structure of bovine serum albumin (BSA) adsorbed to three surfaces: gold, polystyrene (PS), and poly(D,L-lactic acid) (PDLLA). Tertiary structural analysis is important because typical secondary structural analysis (FTIR and CD) is not always sensitive enough to distinguish between the sometimes subtle protein structural changes caused by adsorption. The polymers are spin-coated onto a gold surface, exposed to protein, and then immersed in a deuterated buffer solution to probe the protein's tertiary structure before the sample is removed from its aqueous environment.

Local thickness and anisotropy approaches to characterize pore size distribution of three-dimensional porous networks.

Two image-analysis approaches for pore size distribution (PSD) of porous media are proposed. The methods are based on the skeleton representation of a porous object. One approach gives the local thickness of the pore object to represent the pore size corresponding to a lower limit of PSD.

Time-dependent effects of pre-aging polymer films in cell culture medium on cell adhesion and spreading.

We have tested the hypothesis that cell adhesion and spreading on polymer films are influenced by the amount of time that the polymer films are pre-aged in cell culture medium. Cell adhesion and spreading were assessed after a 6-h culture on poly(D,L-lactic acid) (PDLLA) films that had been pre-aged in cell culture medium for 30 min, 1, 3 or 7 d. Cell adhesion and spread area were enhanced as the duration of pre-aging PDLLA films in cell culture medium was increased.

Gradient substrate assembly for quantifying cellular response to biomaterials.

Using quantitative fluorescence microscopy in conjunction with a method of gradient substrate assembly established in their group, the authors were able to introduce and measure reproducible changes in cellular morphology and cell density by manipulating polymer grafting density. The mechanism behind this change in cellular behavior was explained by a semiempirical, geometric model that describes the effect of the spatial distribution of the polymer on protein attachment. A 10-fold increase in graft density of poly(2-hydroxyethyl methacrylate) [PHEMA] along the surface of a gradient sample, preexposed to bovine fibronectin, caused a change in the size of fibroblasts on the surface (i.

Using surrogate modeling in the prediction of fibrinogen adsorption onto polymer surfaces.

We present a Surrogate (semiempirical) Model for prediction of protein adsorption onto the surfaces of biodegradable polymers that have been designed for tissue engineering applications. The protein used in these studies, fibrinogen, is known to play a key role in blood clotting. Therefore, fibrinogen adsorption dictates the performance of implants exposed to blood.