RESUMO
A commercial biomedical Polyimide (PI) film was topographically and chemically modified by generating micrometric periodic arrays of lines using Direct Laser Interference Patterning (DLIP) in order to improve antifouling and antibacterial properties. DLIP patterning was performed with periods from 1⯵m to 10⯵m. The physical modification of the surface was characterized by SEM, AFM and contact angle measurements and, the chemical composition of the ablated surfaces was analyzed by ATR-IR and XPS spectroscopies. The antibacterial effects were evaluated through the effect on Pseudomonas aeruginosa colonies growth on the LB (Luria Bertani) broth. The results showed that the laser treatment change the topography and as a consequence the chemistry surface, also that the microstructured surfaces with periods below 2⯵m, exhibited a significant bacterial (P. aeruginosa) adhesion decrease compared with non-structured surfaces or with surfaces with periods higher than 2 µm. The results suggest that periodic topography only confer antifouling properties and reduction of the biofilm formation when the microstructure presents periods ranging from 1⯵m to 2⯵m. On the other hand, the topography that confer strong antifouling superficial properties persists at long incubation times. In that way, polymer applications in the biosciences field can be improved by a surface topography modification using a simple, single-step laser-assisted ablation method.
Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Desenvolvimento de Medicamentos , Pseudomonas aeruginosa/efeitos dos fármacos , Resinas Sintéticas/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Aderência Bacteriana/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Resinas Sintéticas/síntese química , Resinas Sintéticas/química , Propriedades de SuperfícieRESUMO
The ethyl-4-dimethylaminobenzoate (EDAB) is widely used as a coinitiator of the camphorquinone (CQ), but in acidic circumstances it might present some instability, reducing the polymerization efficiency of the material. Considering this, new coinitiators are being evaluated. Hence, this study evaluated the kinetic of polymerization (KP), the degree of conversion (DC), and the rate of polymerization (RP ) of experimental resin adhesives containing 1,3-diethyl-2-thiobarbituric acid (TBA) as a coinitiator of the CQ. The experimental monomeric blend was prepared with bisphenol A glycidyl dimethacrylate, 2-hydroxyethyl methacrylate, and acidic monomers. CQ was added at 1 mol % as photoinitiator. Six groups were formulated: four containing concentrations of 0.1, 0.5, 1, and 2 mol % of TBA, one without coinitiator, and the last one containing 1 mol % of EDAB (control group). The KP and the RP were performed using real-time Fourier Transform infrared spectroscopy. The group without coinitiator has not formed a polymer, whereas the addition of TBA resulted in the conversion of monomers in polymer. The DC of the adhesives was as higher as the increase in the TBA content. The group with 2 mol % of TBA presented improved DC and reactivity (RP ) than the other groups and the control one. Hence, the TBA has performed as a coinitiator of the CQ for the radical polymerization of methacrylate resin adhesives and it has improved the DC and the reactivity of the materials. Thus, it is a potential coinitiator for the photopolymerization of dental materials.