1.Influence of addition of 2-[3-(2H-benzotriazol-2-YL)- 4-hydroxyphenyl] ethyl methacrylate to an experimental adhesive system.
Centenaro CC1, Rostirolla FV1, Leitune VC1, Parolo CF2, Ogliari FA3, Samuel SM1, Collares FM1. Acta Odontol Latinoam. 2015 Apr;28(1):72-8. doi: 10.1590/S1852-48342015000100010.
The aim of this study was to evaluate the addition of 2-[3-(2HBenzotriazol- 2-yl)-4-hydroxyphenyl]ethyl methacrylate (BTAM) to an experimental adhesive resin. An experimental base adhesive resin was formulated with BisGMA, TEGDMA and HEMA, to which BTAM was added at 1, 2.5 and 5%, in weight. One group with no addition was used as control. The experimental adhesives were evaluated for antibacterial potential (against Streptococcus mutans), degree of conversion with FTIR, softening in solvent and microRaman interface analyses. Data were analyzed by Kruskal-Wallis, paired t test and ANOVA and Tukey, considering a 5% level of significance. The results showed antibacterial activity of 5% BTAM against S. mutans (p<0.05), however, no difference was found among BTAM groups (p> 0.05). The results of degree of conversion and softening of solvent showed no statistical difference between BTAM and control groups (p>0.05). The addition of 5% BTAM showed higher antibacterial activity than the negative control, and copolymerization with comonomer blend of adhesive resin and BTAM was detected at the dentin/ adhesive interface.
2.Rational protein modification leading to resistance of enzymes to TiO2-UV irradiation-induced inactivation.
Lele BS1, Russell AJ. Biomacromolecules. 2004 Sep-Oct;5(5):1947-55.
Photoexcited TiO2 degrades biomolecules such as nucleic acids, cell membrane proteins, and enzymes. Stabilization of enzyme activity against the deactivation caused by the combination of TiO2-UV is essential if we are to develop novel hybrid materials exhibiting photocatalytic and biocatalytic activities useful for decontamination applications. In this paper we describe the stabilization of a model enzyme, chymotrypsin, against TiO2-UV-induced deactivation by conjugating the enzyme with UV-absorbing, carboxyl-terminated oligo[2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate] [oligo(HBMA)-COOH]. Chymotrypsin was completely deactivated within 3 h, whereas the chymotrypsin-oligo(HBMA) conjugate retained > 50% activity even after 5 h of exposure to TiO2-UV (lambdamax 365 nm). The degree of enzyme stabilization induced by the conjugated UV absorber was 2-fold higher than that from the equivalent number of conjugated PEG chains.
3.Enhancing enzyme stability against TiO2-UV induced inactivation.
Lele BS1, Russell AJ. Biomacromolecules. 2005 Jan-Feb;6(1):475-82.
The use of enzymes in conjunction with inorganic photocatalysts requires stability against photooxidation. In this paper, we describe enhanced stabilization of a model enzyme, chymotrypsin, to photooxidation driven by titanium dioxide exposed to ultraviolet light (TiO(2)-UV). Stabilization is achieved conjugating the enzyme with an oligomeric adduct of UV-absorbing (2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate) (HBMA) and free radical-absorbing 2-methacryloyloxyethyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylate (Trolox-HEMA). Juxtaposition of the antioxidant Trolox with the UV absorber HBMA within a single chain reduced the rate of deactivation of the former by TiO(2)-UV. This enables modified enzyme, which is adsorbed on TiO(2), to absorb both UV-light and free radicals and locally reduce the rate of photooxidation. Interestingly, Trolox was more readily deactivated by TiO(2)-UV when it was conjugated separately to chymotrypsin that had been pre-modified with HBMA moieties.