Magnetic Fe3O4nanoparticles were prepared by coprecipitation and then coated with silica. These Fe3O4/SiO2nanoparticles consisted of a 10–15 nm magnetic core and a silica shell of 2–5 nm thickness. The superparamagnetic property of the Fe3O4/SiO2particles with the magnetization of 42.5 emu/g was confirmed by vibrating sample magnetometer (VSM). We further optimized buffers with these Fe3O4/SiO2nanoparticles to isolate genomic DNA of hepatitis virus type B (HBV) and of Epstein-Barr virus (EBV) for detection of the viruses based on polymerase chain reaction (PCR) amplification of a 434 bp fragment ofSgene specific for HBV and 250 bp fragment of nuclear antigen encoding gene specific for EBV. The purification efficiency of DNA of both HBV and EBV using obtained Fe3O4/SiO2nanoparticles was superior to that obtained with commercialized Fe3O4/SiO2microparticles, as indicated by (i) brighter PCR-amplified bands for both HBV and EBV and (ii) higher sensitivity in PCR-based detection of EBV load (copies/mL). The time required for DNA isolation using Fe3O4/SiO2nanoparticles was significantly reduced as the particles were attracted to magnets more quickly (15–20 s) than the commercialized microparticles (2-3 min).

Since the discovery of ordered mesoporous silica M41S in 1992, a variety of ordered mesoporous materials have been synthesized by using the template technique. In this work, aminosilane-modified SBA-15 nanoparticles were prepared by incorporating various aminosilanes on original SBA-15 via post synthesis method. These aminosilanes were 3-aminopropyltriethoxysilane, N-2(-aminoethyl)-3-aminopropyl trimethoxysilane and (3-trimethoxysilylpropyl)diethylenetriamine. The synthesized nanoparticles were characterized by XRD, SEM, TEM and FT-IR. Adsorption and release studies of bovine serum albumin (BSA), lysozyme and myoglobin on SBA-15 samples were investigated. It was found that the synthesized SBA-15 nanoparicles can be successfully applied in drug delivery system.

Streptococcus mutans and other certain oral lactic-acid bacteria have demonstrated to possess the ability to carry out malolactic fermentation involving decarboxylation of L-malate to yield L-lactic acid and concomitant reduction in acidity. The activity is inducible by L-malate in S. mutans growing in suspensions or biofilms. Alkalinization is associated with malolactic fermentation resulted in pH rise. Malolactic fermentation (MLF) has been identified as a major system for alkali production by oral streptococci, including S. mutans. Our major objectives in the work described here were to examine the effects of weak acids and some phytochemicals on MLF by S. mutans in both suspension and biofilm states. The obtained data indicated that all week acids tested including triclosan, indomethacin, carpric acid, fluoride and lauric acid inhibited MLF by S. mutans at IC 50 of 0.22, 0.25, 0.08, 4.8 và 2.2 mM, respectively. The biofilm cells were also sensitive to the tested agents but at concentration of 10 to 50 folds higher compared to the suspension cells. The inhibition was in a pH dependent manner with increased inhibition was found at lower pH values. For phytochemicals, including -mangostin and asiatic acid, only mangostin showed to be potent for MLF of cells in both suspension and biofilms with IC 50 of ca. 45 and > 120 M, respectively. Asiatic acid had no effect on MLF even at a high concentration of > 50 mM. The net conclusion is that MLF of S. mutans is sensitive to -mangostin and weak acids, including fluoride and triclosan, which are commonly added to oral care products.