Search

The effective control of biointerfacial interactions is of outstanding interest in a broad range of biomedical applications, ranging from cell culture tools to biosensors and implantable medical devices. For many of these applications, highly specific interactions between cells and material surfaces are desired. Sophisticated control over these interactions requires reducing or preventing non-specific interactions on the one hand and displaying highly specific signals that can be recognized by extracellular receptors on the other. We have recently developed ultra-low fouling coatings that can be applied in a single step using photoreactive copolymers of 2-hydroxypropyl acrylamide and N-benzophenone acrylamide. Here, we have expanded this approach by incorporating polymerizable peptide monomers into these copolymers. The monomers QQGWFGAGK(acrylamide) and acrylamide-GAGQQGWF were synthesized after identifying the QQGWF sequence as a binding motif for CD44 by phage display for the first time. Our results demonstrate that UV-crosslinked coatings fabricated using the QQGWFGAGK(acrylamide) monomer are effective at selectively binding hMSC in the presence of HepG2 and HEK293 cells due to the difference in CD44 expression. Our results also demonstrate that the peptide modified coatings retain their low biofouling character using a BCA protein binding assay as well as an E. coli bacterial attachment assay over a 24 h period. Our approach provides an alternative to traditional integrin-mediated selective cell binding on surfaces and opens the door to new diagnostic applications, exploiting the fact that the transmembrane protein CD44 is highly expressed in multiple diseases., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Hydrophilic epoxy resin-based monoliths were employed as cell culture substrates. The monoliths were made of a porous material with a bicontinuous structure that consisted of a porous channel and a resin skeleton. Monolith disks were prepared with a skinless surface through polymerization-induced spinodal decomposition-type phase separation. The pore sizes, which were well controlled by the polymerization temperature, ranged from 70 to 380 nm. The quantity of protein adsorbed per unit area and the early-stage adhesion of HepG2 cells on the monolith substrates were independent of pore size, meaning they were not affected by surface topology. Long-term cell adhesion, as indicated by adherent cell number and shape, as well as liver-specific gene expression were significantly affected by pore size. In terms of cell shape, number, and gene expression, pores of approximately 200 nm were most suitable for HepG2 cell growth. These results highlight the importance of monolith morphology for use as a cell culture substrate. The well-controlled morphology demonstrated in this work indicates monoliths are capable of supporting growth for various types of cells in a range of applications., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Biofouling, an undesired adsorption of biological material to otherwise inert surfaces, is detrimental in medical, pharmaceutical, and other sectors. Concentrated polymer brushes (CPB) confer non-biofouling properties on modified surfaces but are cumbersome to fabricate. Here, a simple and versatile method of fabricating non-biofouling coatings for various substrates was developed using CPB-modified silica nanoparticles (SiPs). Concentrated poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMA) brushes were grafted on SiPs by surface-initiated atom transfer radical polymerization. CPB-SiPs were spin-coated onto silicon wafers or quartz crystal microbalance (QCM) sensor chips with phenyl azido cross-linkers. SiP cross-linking was then performed by ultra violet irradiation for 20s, or by heating at 120°C for 12h. Protein adsorption to coatings was studied by QCM approach and human umbilical vein endothelial cell adhesion to coatings was examined. SiP to cross-linker weight ratios were varied from 2.0/0.5 to 9.0/0.5 (wt/wt%) and the coatings almost completely suppressed protein adsorption and cell adhesion to treated surfaces. The coating was also applied to polymeric films, rendering these materials biofouling-resistant., (Copyright © 2016 Elsevier B.V. All rights reserved.)