Cationic polyelectrolyte hydrogel fosters fibroblast spreading, proliferation, and extracellular matrix production: Implications for tissue engineering

Abstract

Fibrous encapsulation is known to occur to many prosthetic implants and is thought to be due to the cells not adhering adequately to the surface. For developing new materials able to enhance cellular adhesion by mimicking extracellular matrix components, polyelectrolyte polymers, characterized by tunable surface charges, have been proposed. Here we demonstrate that panoply of cell functions over a two-dimensional substratum is influenced by surface charge. We have at first generated structurally related polyelectrolyte substrata varying in their positive surface charge amount and subsequently evaluated a variety of behaviors of human primary fibroblasts seeded on these polymers. The proportion of adherent, spreading, and proliferating cells was increased significantly on cationic hydrophilic surfaces when compared with the neutral base surface. The extent of cell spreading correlated with cytoskeleton organization as assessed using immunofluorescence techniques. In the key experiment, the presence of cationic charges on cell adhesion-resistant neutral surface increased the synthesis of collagen I and III, the release of their metabolites, and the expression of their mRNA by fibroblasts. Interestingly, the scarce collagen deposits on neutral polymer consisted, for the most part, of collagen I while collagen III was present only in traces probably due to the secretion of metalloproteinase-2 by non-adherent fibroblasts. Taken together, these results show that polyelectrolyte films may promote the attachment of fibroblast cells as well as their normal secretory phenotype. Both effects could be potentially useful in integrating soft connective tissue to the implant, decreasing the chance of its fibrous encapsulation.

Influence of Titanium Surface Charge on Fibroblast Adhesion

“…33 Kapur and colleagues evaluated the passive adsorption of proteins in cell free culture medium to fluorinated ethylene propylene (FEP) and bacteriologicgrade polystyrene (PS). One explanation of this behavior of cell adhesion was that the titanium surface electrical charge affects the adsorbed protein layer composition, thus favoring the fibroblast adhesion to the positively charged titanium surface.…”

“…[14][15][16][17][18][19][20][21] The dentogingival fibers perpendicularly attached to the cementum form part of an abutment to the sulcular epithelium. 28,[32][33][34] However, variables inherent in chemically charged surfaces used in previous studies make it difficult to separate the electrical charge and chemical effects. It has been suggested that the creation of a perpendicular insertion of collagen fibers to the implant surface would enhance the barrier capacity and reduce the implant failure rate.…”

“…12 However, in a previous study, parallel collagen fiber orientation to nonsubmerged titaniumcoated implants was observed, with no apical migration of the junctional epithelium. 28,32,33,35 In the present study, a potential difference to titanium cylinders was applied to generate positive and negative surface charges. 17 From the above-mentioned studies, it might be concluded that enhancement of fibroblast adhesion and improvement in the insertion direction of collagen fibers to the titanium implant surface might improve the biologic seal around the dental implant and the resistance of peri-implant mucosa to inflammation and bacterial invasion.…”

Synthetic hydrogel niches that promote hMSC viability

“…In essence, these two situations allow the creation of cellular niches that simply permit cells to function or actively present cues that promote selected functions. To date, researchers have explored the development of hydrogels for the delivery of numerous primary cells, including chondrocytes Anseth, 2001, 2002;Bryant et al, 2004;Paige et al, 1995;Rice and Anseth, 2004;Sittinger et al, 2004), osteoblasts Sittinger et al, 2004), valvular interstitial cells (Masters et al, 2004), smooth muscle cells (Mann, 2003;Mann et al, 2001;Moffat and Marra, 2004;Ramamurthi and Vesely, 2005), fibroblasts (De Rosa et al, 2004;Shu et al, 2004;Zielinski and Aebischer, 1994), and mesenchymal stem cells (Lawson et al, 2004;Nuttelman et al, 2004;Schantz et al, 2003;Temenoff et al, 2004;Wang et al, 2003;Williams et al, 2003).…”

Culture of dermal fibroblasts and protein adsorption on block conetworks of poly(butyl methacrylate-block-(2,3 propandiol-1-methacrylate-stat-ethandiol dimethacrylate))

“…Factors that are often cited as being important include surface chemistry [1], hydrophobicity/ hydrophilicity [2,3], mechanical properties [4][5][6][7], surface energy [8], porosity [9], roughness [10][11][12][13][14][15] and charge [16,17]. Recently, we have been successful in designing experiments that allow us to produce sets of amphiphilic cross-linked materials (amphiphilic conetworks) that have different porosities (and related surface roughness) and are structured into nano-phase separated domains [18].…”