No abstract

A targeting drug delivery system using folate-conjugated pluronic F127/chitosan core-shell nanoparticles was developed to deliver doxorubicin (DOX) to the target cancer cells. First, DOX was encapsulated in pluronic F127 micelle cores in the presence of sodium dodecyl sulfate (SDS) by a self-assembly method. To form a shell, a layer of either chitosan or folate-conjugated chitosan was deposited onto the pluronic micelles. The encapsulation efficiency was approximately58.1±4.7%. The average size of the core-shell nanoparticles was37.4±2.0 nm, while the zeta potential was12.9±2.3 mV, indicating the presence of a shell layer and more stable particles. In anin vitroDOX release study, an initial burst release, followed by a sustained release, was observed within 24 hours. In addition, the core-shell nanoparticles showed greater cytotoxicity towards MCF-7 cells than free DOX, suggesting a better therapeutic efficacy in treating cancer.

Poly(N-isopropylacrylamide-co-acrylamide) (PNIAM-co-AM)grafted surfaces have been reported to promote cell adhesion and detachment by a hydrophobic-to-hydrophilic transition triggered by temperature change. However, the surface uniformity and cell detachment consistency are still an issue. In this study, PNIAM-co-AM is prepared with spin coating to control the grafting density and the thickness and to achieve better cell detachment. The atomic force microscopy results indicate that the surface becomes smoother as the spin speed increases. The attenuated total reflection Fourier transform infrared results show a grafting density from 1.68 to 2.03 μg/cm 2 . Ellipsometry suggests that the thickness of the spin-coated PNIAM-co-AM layer is 11−21 nm. The grafted surfaces were tested with mouse preosteoblast MC3T3-E1 cells, which grew successfully. The detachment reached 100 percent with the samples prepared with 1.5 and 2 h ultraviolet exposure times without the use of a poly(vinylidene difluoride) membrane. The detached sheet was in good condition, as indicated by Live/Dead stains.

A novel temperature-responsive tissue culture surface was prepared using ultraviolet irradiation to graft poly(N-isopropylacrylamide-co-acrylamide) (PNIAM-co-AM) onto commercial tissue culture surfaces. The physical properties of the grafted surfaces were confirmed by Fourier Transform Infrared Spectroscopy, contact angle measurement, and Atomic Force Microscopy. The grafted surface was also tested and shown to be nontoxic using mouse preosteoblast MC3T3-E1 cells. The cells grew as successfully on the grafted surface as those on ungrafted surface. When the temperature was reduced from 37 to 10 C for 30 min, followed by 20 C for 60 min, the confluent cells could be detached as a continuous sheet. A histological examination showed that the harvested cell sheet preserved tight junctions and extracellular matrix proteins, allowing the sheet to adhere to other cell sheets as multilayers. The resulting multilayered sheets were in good condition, as indicated by the LIVE/DEAD stain.

Low level laser therapy is widely used to relieve pain and inflammation, and to restore cellular functions. The photons of light are absorbed by mitochondria in cells, leading to an increase in the production of adenosine triphosphate (ATP), nitric oxide release, blood flow, and reactive oxygen species (ROS). This study proposed the use of a laser diode array at 808 nm to stimulate the proliferation and to activate the functions of dermal papilla cells, which were an important part of the hair growth cycle. These cells were isolated from human hair follicles and were exposed to 808 nm light at various doses from 0.5, 1, 2.5, 4, and 6 J/cm. The rate of cell proliferation and the gene expression profile of dermal papilla cells were investigated and compared with the control in which the cells did not received any light treatment. The growth curves of the dermal papilla cells were used to determine the specific growth rates. Higher specific growth rates were observed in the cells exposed to laser at doses higher than 0.5 J/cm. The effect of the laser light treatment on several gene markers, specifically for dermal papilla cells, was evaluated using real-time polymerase chain reaction (qPCR). Our result shows that collagen type 1 (Col1), alkaline phosphatase (Alp), and versican (Vcan) did not increase when the cells were irradiated by the laser light. Interestingly, sex determining region y-box 2 (Sox2) gene was up-regulated when 0.5 J/cm, and 1 J/cm light was used, while an increase in the level of fibroblast growth factor 7 (Fgf7) gene was observed with light irradiation at 0.5 J/cm, 1 J/cm, 2.5 J/cm, and 4 J/cm. Too high irradiation dose was shown to yield no effect on the gene expression of dermal papilla cells.