Effect of Common Consumer Washing Methods on Bisphenol A Release in Tritan Drinking Bottles.

Bisphenol A (BPA)-free plastic products are widely available. Transient BPA release has been reported in Tritan drinking bottles. This study assessed the effectiveness of common consumer washing methods in removing BPA contamination in Tritan bottles using both ELISA and HPLC-MS/MS assays. BPA release was detected in 2 out of 10 kinds of Tritan drinking bottles tested. Average BPA level was 0.493 µg/L in water samples from a type of Tritan kid drinking bottle following 24-hour incubation at room temperature, corresponding to a release rate of 0.015 ng/cm2/h. Of the common consumer cleaning methods identified in an informal survey, dishwashing was the most effective method that significantly reduced, even eliminated BPA release from the tested BPA-positive Tritan bottles, while rinsing with water and handwashing with soap and water were ineffective. The bioactivity of the leached BPA was confirmed using a rodent cardiac myocyte acute exposure model and an invertebrate 7-day exposure model. The BPA release is possibly the result of surface contamination in the manufacturing process. As a case study, our result may be informative for general consumer practice and for better quality control by the manufactures.

Fabrication of chitosan/silk fibroin composite nanofibers for wound-dressing applications.

Chitosan, a naturally occurring polysaccharide with abundant resources, has been extensively exploited for various biomedical applications, typically as wound dressings owing to its unique biocompatibility, good biodegradability and excellent antibacterial properties. In this work, composite nanofibrous membranes of chitosan (CS) and silk fibroin (SF) were successfully fabricated by electrospinning. The morphology of electrospun blend nanofibers was observed by scanning electron microscopy (SEM) and the fiber diameters decreased with the increasing percentage of chitosan. Further, the mechanical test illustrated that the addition of silk fibroin enhanced the mechanical properties of CS/SF nanofibers. The antibacterial activities against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) were evaluated by the turbidity measurement method; and results suggest that the antibacterial effect of composite nanofibers varied on the type of bacteria. Furthermore, the biocompatibility of murine fibroblast on as-prepared nanofibrous membranes was investigated by hematoxylin and eosin (H&E) staining and MTT assays in vitro, and the membranes were found to promote the cell attachment and proliferation. These results suggest that as-prepared chitosan/silk fibroin (CS/SF) composite nanofibrous membranes could be a promising candidate for wound healing applications.

Preparation of core-shell biodegradable microfibers for long-term drug delivery.

A coaxial electrospun technique to fabricate core-shell microfibers (MFs) for drug delivery application is described. In one-step, Paclitaxel (PTX)-loaded poly(L-lactic acid-co-epsilon-caprolactone) (75:25) (P(LLA-CL)(core/shell)) was electrospun into MFs using 2,2,2-trifluoroethanol as the solvent. The physical and chemical properties of electrospun fibers were characterized by various techniques, such as scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, and Fourier-transform infrared. The fiber diameter depended on both the polymer concentration and the flow ratio of PTX to P(LLA-CL). The encapsulation efficiency and in vitro release profile were measured using high performance liquid chromatography methods. PTX released from the MFs in a short burst over 24 h followed by very slow release over the following 60 days. In addition, the cytotoxicity of PTX-loaded P(LLA-CL) MFs was evaluated using 3-[4,5-dimehyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide assay on HeLa cell lines. These results indicate that PTX could be released from P(LLA-CL) fibers in a steady manner and effectively inhibit the activity of HeLa cells.