Incorporation of Fluorescent Fluorinated Methacrylate Nano-Sized Particles into Chitosan Matrix Formed as a Membranes or Beads

Abstract

Fluorescent particles are of particular interest as probes and active agents for biomedical, pharmaceutical, and food applications. Here, we present two strategies for incorporation of core-shell acrylic fluorescent nanoparticles (NPs) with Rhodamine B (RhB) as a dye into a chitosan (CS) matrix. We selected two variants of NPsRhB immobilisation in a CS membrane and biopolymeric CS beads. Modification of the method for production of the biopolymer cover/transporter of nanoparticles allowed two series of hydrogels loaded with nanoparticles to be obtained with a similar concentration of the aqueous solution of the nanoparticles. Microscopic analysis showed that the NPs were nonuniformly distributed in millimetre-sized CS beads, as well as membranes, but the fluorescence signal was strong. The composition of CS layers loaded with nanoparticles (CS/NPsRhB) showed water vapour barrier properties, characterised by the contact angle of 71.8°. Finally, we incorporated NPsRhBCS beads into a gelatine matrix to check their stability. The results confirmed good stability of the NPsRhBCS complex system, and no dye leakage was observed from the beads and the membranes. The proposed complex system demonstrated promising potential for further use in bioimaging and, thus, for the development of advanced diagnostic tools.

Human Enamel Fluorination Enhancement by Photodynamic Laser Treatment

“…In fact, the absorption bands reported in Figure 6 b demonstrate a low resolution level of the phosphate peak for simple fluorinated enamel. On the other side, the obtained FT-IR bands for the enamel treated by fluorination showed the presence of a peak at 3573 cm −1 , which belongs to the hydroxyl groups’ substitution with the fluoride ions in the hydroxyapatite structure, in good agreement with the literature [ 34 ]; this peak is visible in Figure 6 b.Such a complex interaction of fluoride ions has been observed for several dental materials, such as fluorinated methacrylate [ 35 ], fluorinated polyimide [ 36 ], and low-fluorinated oligoamides [ 37 ]. The photodynamic laser treatment effect on the enamel samples ( Figure 6 c) did not cause the appearance of new bands or the disappearance of some bands, in good agreement with the data in literature evaluating other laser wavelengths on dental tissues [ 38 , 39 , 40 , 41 ].…”