Ag-decorated polymer chip for the determination of the respective concentrations of TTD and Hg2+ by surface-enhanced raman scattering.

A "hotspot"-rich Ag-nanoparticle-decorated three-dimensional polymer substrate was fabricated, exhibiting an excellent surface-enhanced Raman scattering (SERS) activity. 4-Mercaptobenzoic acid (MBA) was selected as a probe molecule for comparing the SERS activity on selected substrates. The proposed detection chip with the adsorption of tetramethylthiuram disulfide (TTD) shows an excellent sensitivity for the quantitative determination of TTD and mercury ions (Hg2+). This chip exhibited a high sensitivity for the trace detection of the targets. Interestingly, we found that the adsorbed TTD is selectively sensitive to Hg2+. The SERS band had a significant frequency shift of 11 cm-1 as the concentration of Hg2+ increased from 10-10 to 10-3 mol L-1. More importantly, the frequency shift of the SERS band exhibited an excellent linear relationship with the concentration of Hg2+, and the determination limit for Hg2+ was 10-10 mol L-1. Furthermore, the proposed detection chip shows great application potential for the determination of pesticides and Hg2+.

Deformable liposomes by reverse-phase evaporation method for an enhanced skin delivery of (+)-catechin.

BACKGROUND: (+)-catechin, as the most common catechin isomer, is recognized to be an antioxidant which benefits the skin in many ways. The purpose of the present study was to prepare and evaluate a suitable liposomal delivery systems for (+)-catechin topical application. METHODS: In this study, catechin-loaded conventional liposomal delivery system, deformable conventional liposomal delivery system and deformable liposomes prepared by reverse-phase evaporation (REV) method were compared. The three systems were characterized for liposome particle size, zeta-potential, entrapment efficiency, drug release, permeability across porcine skin and catechin deposition in the skin. RESULTS: It was revealed that the size of deformable conventional liposomes before freeze-drying and deformable REV liposomes after freeze-drying range from 335.6 ± 71.7 nm to 551.1 ± 53.4 nm, respectively, which were considered to be suitable for skin delivery. The deformable REV liposomes had a higher aqueous volume and thus were able to entrap greater amounts of hydrophilic (+)-catechin (50.0 ± 5.9%) compared to conventional (30.0 ± 3.8%) and deformable conventional liposomes (36.1 ± 4.6%). All liposomal formulations exhibited a prolonged catechin release. Compared to deformable liposomes, the REV deformable liposomes showed a significantly better deposition of (+)-catechin while catechin solution did not permeate into the porcine ear skin. CONCLUSION: Among all formulations studied, deformable REV liposomes were considered to be favorable for catechin topical delivery.

Preparation of smooth and macroporous hydrogel via hand-held blender for wound healing applications: in vitro and in vivo evaluations.

Wound dressings play an indispensable role in wound healing. However, traditional wound dressings have several disadvantages, such as poor mechanical properties and small pore diameters, which do not allow sufficient gas exchange. To overcome these shortcomings, this paper reports a polyvinyl alcohol (PVA)-based hydrogel physically crosslinked at -20 °C and containing polyethylene glycol (PEG) and nanohydroxyapatite (HAP). The physical and chemical properties of the hydrogels formed by different stirring methods (stirring with a glass rod or a hand-held homogenizer) were compared. The average roughness of Gel 1 (prepared using a hand-held homogenizer) is 112.6 nm, which is much lower than the average surface roughness of Gel 2 (1222 nm, prepared using a glass rod). Moreover, the hydrogel made by the unconventional mixing method (with a homogenizer) showed better performance, including a more interconnected open-pore microstructure and better mechanical properties. Finally, a full-thickness skin defect test was performed. The experimental results demonstrated that the hydrogel has considerable potential for applications in wound dressings.

Reduction of Abdominal Adhesions with Elecrospun Fiber Membranes in Rat Models.

PURPOSE: The aim of this study was to assess the effects three electrospun fiber membranes on postoperative adhesion formation in rat surgical models. MATERIALS AND METHODS: The PEG-PHBV (polyethylene glycol and poly-ß-hydroxybutyrate valerate), PLA(Polylactic acid) and CS-PEG(chitosan and polyethylene glycol) were used for submicrometric membranes fabrication by electrospinning. A total of 64 SD male rats were randomly divided into 4 groups, one control group and 3 treatment groups, each consisting of 16 rats. The rats were underwent median laparotomy and standardized abrasion of the cecum. The indicated membranes were applied intraperitoneally at the end of the surgical procedure in the treatment groups, while the controls left without treatment. Two and four weeks after surgery respectively, a relaparotomy was made for adhesion grading and histopathological examination, Hydroxyproline (Hyp) levels at the adhesion sites in each group were measured. RESULTS: The electrospun submicrometric membranes significantly reduced not only the incidence of adhesion but also the adhesion grading scales (p < 0.05 compared to the control group) at both two weeks and four weeks after the initial operation. Furthermore, the fibrosis grades were also higher in control groups as compared with the submicrometric membrane groups. Hyp levels in the control group was significant higher than the three experiment groups at both 2 and 4 weeks time points (p < 0.05). There were no statistical differences between the different treatment groups at either time points. CONCLUSIONS: Three electrospun submicrometric membranes were soft, flexible, easy to handle, and effectively reduced adhesion formation in rat modes.

Staple Fixation Against Adhesive Fixation in Laparoscopic Inguinal Hernia Repair: A Meta-Analysis of Randomized Controlled Trials.

PURPOSE: The aim of this article was to compare the outcomes of tissue adhesive fixation and the staple fixation of meshes in laparoscopic inguinal hernia repair. MATERIALS AND METHODS: A systematic literature review was undertaken to identify studies that compare adhesive fixation and staple fixation of meshes in laparoscopic inguinal hernia repair. RESULTS: The present meta-analysis pooled the effects of outcomes of a total of 1228 patients enrolled into 8 randomized controlled trials. Tissue adhesive fixation of the mesh was associated with less chronic postoperative pain after laparoscopic inguinal hernia repair compared with staple fixation (risk difference=-0.06; 95% confidence interval, -0.08, -0.04). However, statistically, there was no significant difference in the incidence of acute postoperative pain, recurrence, hematoma/seroma, and wound infection. CONCLUSION: The use of the tissue adhesive fixation method reduces the incidence of chronic postoperative pain after laparoscopic inguinal hernia repair, and without any changes in the other outcomes.

Development of a novel niosomal system for oral delivery of Ginkgo biloba extract.

BACKGROUND: The aim of this study was to develop an optimal niosomal system to deliver Ginkgo biloba extract (GbE) with improved oral bioavailability and to replace the conventional GbE tablets. METHODS: In this study, the film dispersion-homogenization method was used to prepare GbE niosomes. The resulting GbE niosome suspension was freeze-dried or spray-dried to improve the stability of the niosomes. GbE-loaded niosomes were formulated and characterized in terms of their morphology, particle size, zeta potential, entrapment efficiency, and angle of repose, and differential scanning calorimetry analysis was performed. In vitro release and in vivo distribution studies were also carried out. RESULTS: The particle size of the optimal delivery system prepared with Tween 80, Span 80, and cholesterol was about 141 nm. There was a significant difference (P < 0.05) in drug entrapment efficiency between the spray-drying method (about 77.5%) and the freeze-drying method (about 50.1%). The stability study revealed no significant change in drug entrapment efficiency for the GbE niosomes at 4°C and 25°C after 3 months. The in vitro release study suggested that GbE niosomes can prolong the release of flavonoid glycosides in phosphate-buffered solution (pH 6.8) for up to 48 hours. The in vivo distribution study showed that the flavonoid glycoside content in the heart, lung, kidney, brain, and blood of rats treated with the GbE niosome carrier system was greater than in the rats treated with the oral GbE tablet (P < 0.01). No flavonoid glycosides were detected in the brain tissue of rats given the oral GbE tablets, but they were detected in the brain tissue of rats given the GbE niosomes. CONCLUSION: Niosomes are a promising oral system for delivery of GbE to the brain.