Abstract
High-throughput methods allow rapid examination of parameter space to characterize materials and develop new polymeric formulations for biomaterials applications. One limitation is the difficulty of preparing libraries and performing high-throughput screening with conventional instrumentation and sample preparation. Here, we describe the fabrication of substrate materials with controlled gradients in composition by a rapid method of micromixing followed by a photopolymerization reaction. Specifically, poly(ethylene glycol) dimethacrylate was copolymerized with a hyperbranched multimethacrylate (P1000MA or H30MA) in a gradient manner. The extent of methacrylate conversion and the final network composition were determined by near-infrared spectroscopy, and mechanical properties were measured by nanoindentation. A relationship was observed between the elastic modulus and network crosslinking density. Roughness and hydrophilicity were increased on surfaces with a higher concentration of P1000MA. These results likely relate to a phase segregation process of the hyperbranched macromer that occurs during the photopolymerization reaction. On the other hand, the decrease in the final conversion in H30MA polymerization reactions was attributed to the lower termination rate as a consequence of the softening of the network. Valvular interstitial cell attachment was evaluated on these gradient substrates as a demonstration of studying cell morphology as a function of the local substrate properties. Data revealed that the presence of P1000MA affects cell–material interaction with a higher number of adhered cells and more cell spreading on gradient regions with a higher content of the multifunctional crosslinker.
Highlights
The interaction of cells with materials is an extremely complicated subject, but one that is of high importance in both cell biology and biomaterial design.[1]
Gradient materials were fabricated using a microfluidics method followed by a photopolymerization process to create a crosslinked network with spatially varying composition of two hyperbranched macromers (P1000MA and H30MA) with a PEGDM
The characteristic absorption bands located at 4743 and 6162 cmÀ1 represent the methacrylate double bond stretch, and the decrease in height and area is proportional to the methacrylate conversion
Summary
The interaction of cells with materials is an extremely complicated subject, but one that is of high importance in both cell biology and biomaterial design.[1] The studies of cellular responses to substrates suggest that cells are sensitive to the chemical functionality, topography and underlying mechanics.[2,3,4] One important problem in studies comparing different types of polymers is that the compositions can be heterogeneous both chemically and physically (e.g., different surface chemistry, charge, roughness, rigidity, and crystallinity), which may result in considerable variation in experimental results Another methodological problem is that the evaluation of cell function on polymer surfaces is often tedious, because of the large number of samples and the preparation that is required to study the range of desired parameters of interest. A number of research groups have focused on the preparation of substrates with a gradually varying chemical composition along one dimension,[6,7,8] and these ‘‘gradient surfaces’’ are providing facile approaches to screen and identify the effects of specific materials properties on basic cell functions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
