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A DLP 3D printer was used to reproduce several objects (a trunk scaffold, a cube, and a dental crown) in order to ascertain the conditions to obtain the best resolution. The polymerizing solution was a mixture of BisGMA, TEGDMA, and UDMA monomers. The photoinitiator was triphenyl phosphinic oxide (TPO) at various concentrations in the presence and absence of the UV-light blocker 2.5-bis (5'-tert-butyl 2-benzoxazolyl)thiophene (Datilux OB). The printed objects were analyzed by Scanning Electron Microscopy. It was found that the best results were obtained using concentrations of 1 and 2% m/m of TPO in the presence of 0.1% of the UV-blocker. This blocker has an absorption spectrum similar to the photoinitiator and avoids secondary photoinitiations due to reflections that may cause imperfections in the printed objects. The effect of the UV-blocker was evaluated by thermal analysis of the obtained polymers showing that in the presence of the blocker 3–4 times more monomers remained unpolymerized, indicating that the more irregular objects were due to the excess of undesired polymerization. ShoreD hardness of the dental crown material was around 80, within the values reported for other dental materials. [ABSTRACT FROM AUTHOR]

The polymerization of styrenesulfonate photoinitiated by visible light in the presence of dye safranine was studied using various monomer concentrations in aqueous solution. It was found that photopolymerization proceeds in the presence of air and ground state and excited state interactions as well as polymerization products suggested aggregation of the monomer containing dye molecule.

ABSTRACT In this study, pH-responsive amphiphilic chitosan (CS) nanoparticles were used to encapsulate quercetin (QCT) for sustained release in cancer therapy. The novel CS derivatives were obtained by synthesis with 2,3-epoxy-1-propanol, also known as glycidol, followed by acylation with dodecyl aldehyde. Characterization was performed by spectroscopic, viscosimetric, and size-determination methods. Critical aggregation concentration, morphology, entrapment efficiency, drug release profile, cytotoxicity, and hemocompatibility studies were also carried out. The average size distribution of the self-assembling nanoparticles measured by dynamic light scattering ranged from 140 to 300 nm. In vitro QCT release and Korsmeyer-Peppas model indicated that pH had a major role in drug release. Cytotoxicity assessments indicated that the nanoparticles were non-cytotoxic. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay further revealed that QCT-loaded nanoparticles could inhibit MCF-7 cell growth. In vitro erythrocyte-induced hemolysis indicated the good hemocompatibility of the nanoparticles. These results suggest that the synthesized copolymers might be potential carriers for hydrophobic drugs in cancer therapy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45678. [ABSTRACT FROM AUTHOR]