Thermoplastic polyurethane surface coated with polymer brushes for reduced protein and cell attachment.

The objective of this study was to coat negatively charged polymer brushes covalently onto the surface of thermoplastic polyurethane (TPU) using a simple conventional surface free-radical polymerization technique. The coated surfaces were assessed with contact angle, protein adsorption, cell adhesion and bacterial adhesion. Bovine serum albumin (BSA) and bovine fibrinogen (BFG) were used for protein adsorption evaluation. Mouse fibroblasts (NIH-3T3) and Pseudomonas aeruginosa (P. aeruginosa) were used to assess surface adhesion. Results show that the TPU surface modified with the attached polymer brushes exhibited significantly reduced contact angle, protein adsorption, and cell as well as bacterial adhesion, among which the negatively charged polymers showed the extremely low values in all the tests. Its contact angle is 5°, as compared to 70° for original TPU. Its BSA, BFG, 3T3 adhesion and P. aeruginosa adhesion were 93%, 84%, 92%, and 93% lower than original TPU. Furthermore, the TPU surface coated with negatively charged polymer brushes exhibited a hydrogel-like property. The results indicate that placing acrylic acids using a simple surface-initiated free-radical polymerization onto a TPU surface and then converting those to negative charges can be an effective and efficient route for fouling resistant applications.

A novel antibacterial zirconia-containing PMMA bone cement.

A non-leaching antibacterial bone cement has been developed and evaluated. Chlorine- and bromine-containing furanone derivatives were synthesized and covalently coated onto the surface of zirconia filler particles, followed by mixing into a conventional poly(methyl methacrylate) bone cement. Flexural strength and bacterial viability were used to evaluate the modified cements. Effects of coated antibacterial moiety content, coated zirconia loading and halogen on furanone were investigated. Results showed that the experimental cement showed significant enhanced antibacterial function against bone-associated Gram-positive Staphylococcus aureus as well as Gram-negative Pseudomonas aeruginosa, as compared to commercial PMMA cement. The cement also exhibited a comparable flexural strength to and 3-14% higher flexural modulus than commercial PMMA bone cement. Increasing antibacterial moiety content and filler loading significantly enhanced antibacterial activity. Increasing antibacterial moiety content slightly increased both flexural strength and modulus of the modified cement. Increasing filler loading slightly increased flexural strength up to 7% loading and then decreased. The bromine-containing furanone modified cement showed a higher antibacterial activity than its chlorine counterpart. Antibacterial agent leaching tests exhibited that the modified experimental cement showed no leachable antibacterial components to surroundings. Within the limitations of this study, this experimental poly(methyl methacrylate) cement may find potential applications in orthopedics for reducing in-surgical and post-surgical infection after further investigations are conducted.

An antibacterial dental light-cured glass-ionomer cement with improved hardness.

An antibacterial dental light-cured glass-ionomer cement has been developed and evaluated. An antibacterial furanone derivative was synthesized and covalently attached onto the surface of alumina filler particles. The formed antibacterial fillers were then mixed into a light-curable glass-ionomer cement formulation. Surface hardness and bacterial viability were used to evaluate the modified cements. Effects of coated furanone moiety content on the modified fillers, modified alumina filler particle size and loading, and total glass filler content were investigated. Results showed that increasing antibacterial furanone content, modified particle size and loading, and total glass filler content generally increased surface hardness. Increasing furanone moiety, filler loading and total filler content increased antibacterial activity. On the other hand, increasing particle size decreased antibacterial activity. The leaching tests indicate that the modified experimental cement showed no leachable antibacterial component to bacteria and cells.

A self-cured glass-ionomer cement with improved antibacterial function and hardness.

A novel antimicrobial dental self-cured glass-ionomer cement has been developed and evaluated. Alumina filler particles were covalently coated with an antibacterial polymer and blended into a self-cured glass-ionomer cement formulation. Surface hardness and bacterial viability were used to evaluate the modified cements. Results showed that the modified cements exhibited a significantly enhanced antibacterial activity along with improved surface hardness. Effects of antibacterial moiety content, alumina particle size and loading, and total filler content were investigated. It was found that increasing antibacterial moiety content, particle size and loading, and total filler content generally increased surface hardness. Increasing antibacterial moiety, filler loading and total filler content increased antibacterial activity. On the other hand, increasing particle size showed a negative impact on antibacterial activity. The leaching tests indicate no cytotoxicity produced from the modified cements to both bacteria and 3T3 mouse fibroblast cells.

An improved dental composite with potent antibacterial function.

A new BisGMA-based antibacterial dental composite has been formulated and evaluated. Compressive strength and bacterial viability were utilized to evaluate the formed composites. It was found that the new composite exhibited a significantly enhanced antibacterial function along with improved mechanical and physical properties. The bromine-containing derivative-modified composite was more potent in antibacterial activity than the chlorine-containing composite. The modified composites also exhibited an increase of 30-53% in compressive yield strength, 15-30% in compressive modulus, 15-33% in diametral tensile strength and 6-20% in flexural strength, and a decrease of 57-76% in bacterial viability, 23-37% in water sorption, 8-15% in shrinkage, 8-13% in compressive strength, and similar degree of conversion, than unmodified composite. It appears that this experimental composite may possibly be introduced to dental clinics as an attractive dental restorative due to its improved properties as well as enhanced antibacterial function.

Coating polyvinylchloride surface for improved antifouling property.

Antifouling surfaces are specifically crucial to cardiovascular applications. In this study, a polyvinylchloride (PVC) surface was modified by coating a biocompatible and hydrophilic polymer by a mild coating technique. The PVC surface was first activated and then functionalized, followed by coating with the polymer. Results show that the coated hydrophilic polymer significantly reduced 3T3 fibroblast cell adhesion as well as bacteria adhesion. The 3T3 cell adhesion to the polymer-coated surface was reduced to 52-66% as compared to the original PVC surface. Bacterial adhesion to the polymer-coated surface was reduced to 61-80% for Pseudomonas aeruginosa, 65-81% for Staphylococcus aureus, and 73-85% for Escherichia coli, as compared to the original PVC surface. It appears that this novel polymer-coated PVC surface has an antifouling property.

Surface modification of polyurethane with a hydrophilic, antibacterial polymer for improved antifouling and antibacterial function.

Antimicrobial surface is important for the inhibition of bacteria or biofilm formation on biomaterials. The objective of this study was to immobilize a novel hydrophilic polymer containing the antibacterial moiety onto polyurethane surface via a simple surface coating technology to make the surface not only antibacterial but also antifouling. The compound 3,4-dichloro-5-hydroxy-2(5H)-furanone was derivatized, characterized and incorporated onto polyvinylpyrrolidone containing succinimidyl functional groups, followed by coating onto the polyurethane surface. Contact angle, antibacterial function and protein adsorption of the modified surface were evaluated. The result shows that the modified surface exhibited significantly enhanced hydrophilicity with a 54-65% decrease in contact angle, increased antibacterial activity to Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa with a 24-57% decrease in viability, and reduced human serum albumin adsorption with a 64-70% decrease in adsorption, as compared to the original polyurethane.