D-Glucosamine Conjugation Accelerates the Labeling Efficiency of Quantum Dots in Osteoblastic Cells

Quantum dots (QDs) are useful imaging tools in the medical and biological fields due to their optical properties, such as a high fluorescence intensity, remarkable resistance to photobleaching, broad absorption spectra, and narrow emission spectra. This is the first study to investigate the uptake of carboxylated QDs conjugated with D-glucosamine (core size: approximately 3 nm, final modified size: 20-30 nm) into cultured osteoblastic cells. The QDs attached to the cell surface and were transported into the cytoplasm within approximately three hours of culture, whose process was clearly demonstrated using specific fluorescent staining of the cell membrane. Although the intranuclear distribution was not observed, a dramatic decrease in the transfer of quantum dots into the cytoplasm was recognized after approximately seven days of culture. Other interesting phenomena include the escape of the quantum dots from lysosomes in the cytoplasm, as confirmed by the merging of both QD fluorescence and specific fluorescent staining of lysosomes in the cytoplasm. These findings suggest that D-glucosamine conjugation enhances proton absorption in acid organelles and promotes the lysosomal escape of QDs

D-Glucosamine Promotes Transfection Efficiency during Electroporation

D-Glucosamine is a useful medicament in various fields of medicine and dentistry. With respect to stability of the cell membrane, it has been reported that bradykinin-induced nociceptive responses are significantly suppressed by the direct application of D-glucosamine. Electroporation is usually used to effectively introduce foreign genes into tissue culture cells. Buffers for electroporation with or without D-glucosamine are used in experiments of transfection vectors. This is the first study to indirectly observe the stability and protection of the osteoblast membrane against both electric stress and gene uptake (the proton sponge hypothesis: osmotic rupture during endosomes prior to fusion with lysosomes) in electroporation with D-glucosamine application. The transfection efficiency was evaluated as the fluorescence intensity of the transfected green fluorescent protein (GFP) in the cultured cells (osteoblasts; NOS-1 cells). The transfection efficiency increased over 30% in the electroporation samples treated with D-glucosamine-supplemented buffer after one day. The membrane absorption of D-glucosamine is the primary mechanism of membrane stress induced by electric stress. This new function of D-glucosamine is useful and meaningful for developing more effective transformation procedures

Biological Safety of Fish (Tilapia) Collagen

Marine collagen derived from fish scales, skin, and bone has been widely investigated for application as a scaffold and carrier due to its bioactive properties, including excellent biocompatibility, low antigenicity, and high biodegradability and cell growth potential. Fish type I collagen is an effective material as a biodegradable scaffold or spacer replicating the natural extracellular matrix, which serves to spatially organize cells, providing them with environmental signals and directing site-specific cellular regulation. This study was conducted to confirm the safety of fish (tilapia) atelocollagen for use in clinical application. We performed in vitro and in vivo biological studies of medical materials to investigate the safety of fish collagen. The extract of fish collagen gel was examined to clarify its sterility. All present sterility tests concerning bacteria and viruses (including endotoxin) yielded negative results, and all evaluations of cell toxicity, sensitization, chromosomal aberrations, intracutaneous reactions, acute systemic toxicity, pyrogenic reactions, and hemolysis were negative according to the criteria of the ISO and the Ministry of Health, Labour and Welfare of Japan. The present study demonstrated that atelocollagen prepared from tilapia is a promising biomaterial for use as a scaffold in regenerative medicine

Effects of eluted components from 4-META/MMA-TBB adhesive resin sealer on osteoblastic cell proliferation

Background/purpose: Adhesive resin sealer systems are applied to seal root-canal systems more effectively through the formation of a resin impregnation layer. The purpose of this study was to investigate the effects of eluted components of the adhesive, Super-Bond sealer (SBS), on the proliferation of osteoblastic cells in vitro. Materials and methods: The standard powder:liquid ratio according to the manufacturer\u27s instructions was used to produce a cylindrical block of SBS (5 mm in diameter, 10 mm long) for this elution study. The resin block was placed on a 100-mm culture dish. Osteoblastic cells were seeded at a density of 4 × 10 6 in α-minimum essential medium containing 10% fetal bovine serum and cultured in a humidified incubator. After 3 days of culture with or without SBS, cells were retrieved and lysed according to the manufacturer\u27s instructions. The cellular events induced by the eluted components from SBS were analyzed using an antibody assay for mitogen-activated protein kinases (MAPKs) and a 3-(4,5-dimethylthyazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Furthermore, the concentration of boron, a component of the catalyst, tri-n-butyl borane (TBB), was analyzed using inductively coupled plasma optical emission spectrometry. Results: Expression of MAPKs increased after SBS application. The MTT assay indicated that TBB, one of the components of SBS, accelerated the proliferation of osteoblastic cells. Values of boron were 1.66 ± 0.37 and 1.74 ± 0.30 ppm in cells cultured with and without FBS, respectively. Conclusions: The eluted components from SBS can increase the expression of some MAPKs related to osteoblastic cell proliferation and differentiation in vitro. Both the elution experiment and treatment of cell culture with SBS components indicated that the boron originating from TBB is likely to be responsible for activation of the proliferation of osteoblastic cells

D-Glucosamine Conjugation Accelerates the Labeling Efficiency of Quantum Dots in Osteoblastic Cells

Quantum dots (QDs) are useful imaging tools in the medical and biological fields due to their optical properties, such as a high fluorescence intensity, remarkable resistance to photobleaching, broad absorption spectra, and narrow emission spectra. This is the first study to investigate the uptake of carboxylated QDs conjugated with D-glucosamine (core size: approximately 3 nm, final modified size: 20-30 nm) into cultured osteoblastic cells. The QDs attached to the cell surface and were transported into the cytoplasm within approximately three hours of culture, whose process was clearly demonstrated using specific fluorescent staining of the cell membrane. Although the intranuclear distribution was not observed, a dramatic decrease in the transfer of quantum dots into the cytoplasm was recognized after approximately seven days of culture. Other interesting phenomena include the escape of the quantum dots from lysosomes in the cytoplasm, as confirmed by the merging of both QD fluorescence and specific fluorescent staining of lysosomes in the cytoplasm. These findings suggest that D-glucosamine conjugation enhances proton absorption in acid organelles and promotes the lysosomal escape of QDs