Papers by Keyword: Pluronic

Abstract: We have designed a polymer micelles based on Pluronic P₁₂₃ and Polyethyleneimine 600 (termed as P₁₂₃P₆₀₀). Upon critical micelle concentration the P₁₂₃P₆₀₀ unimer formed micelles in water. These micelles not only could simultaneously delivery hydrophobic anticancer drug paclitaxel (PTX) to cancer cells but also could deplete ATP and inhibit P-gp expression in MDR cells. In vitro researches demonstrated that these micelles showed the excellent biocompatibility, high drug loading efficiency, stably controlled releasing behavior, enhanced cellular up-take and improved serum stability. In vivo studies demonstrated that the PTX loaded micelles induced tumor cell apoptosis and inhibited the growth of tumor to overcome drug resistance through a synergistic effect. All these findings suggested that P₁₂₃P₆₀₀ for delivery of anticarcinogen provided a promising strategy for reversal of MDR in cancer treatment.

Abstract: This paper investigates the adsorption behavior of triblock copolymer Poly (propylene oxide)-poly (ethylene oxide)-poly (propylene oxide), PPO-PEO-PPO on silicon and iron surfaces by using the contact angle goniometer, spectroscopic ellipsometer and atomic force microscopy (AFM). After adsorption, the decrease of water contact angle was observed on each surface; and a larger reduction of water contact angle occurred on the surface covered by the copolymer film with longer and higher weight percent of hydrophilic PEO block. This means that the PEO block may be on the top of the adsorbed copolymer film. The film thickness measurement shows that the copolymer with longer and higher weight percent of PPO block forms a thicker film on the hydrophobic surface, which suggests that the hydrophobic PPO block of the copolymer in the aqueous solution plays the main role during the adsorption of PPO-PEO-PPO onto the hydrophobic surface. It has been found from the AFM results that the roughness of the surface decreased after adsorption and the smoother topography was observed on the surface adsorbed by a thicker adsorbed film.

Abstract: Marine mussels secrete remarkable mussel adhesive proteins (MAPs) for adherence to the substrates upon which they reside. Inspired by the intermolecular cross-linking characteristics of MAPs, we report the synthesis of thermosensitive dopamine modified Pluronic copolymer (PluF127-Dopa) with high coupling efficiency. Under certain temperature and concentration, PluF127-Dopa copolymers in aqueous solution self-assemble into micelles and are able to rapidly form a more stable hydrogels upon addition of oxidizing reagents such as NaIO4, resulting from oxidative cross-linking of dopamine. UV-vis spectroscopy was utilized to identify the reaction intermediates. The sol-gel transition curves of cross-linked PluF127-Dopa hydrogels (CL-PluF127-Dopa) were determined by a vial inversion method. The critical gelation concentration of CL-PluF127-Dopa hydrogels was significantly lower than those for PluF127-Dopa and unmodified Pluronic F127. The apparent mechanical strength of CL-PluF127-Dopa hydrogels was dramatically enhanced compared to those unmodified Pluronic copolymer hydrogels, suitable for sustained drug delivery. These new biomimetic materials are expected to have potential uses in biomedical applications.

Abstract: In this study, muscle-derived stem cell (MDSC)/Pluronics/polycaprolactone (PCL) microparticle hybrid mixture was prepared as a potential injectable urethral bulking agent for the treatment of urinary incontinence. The MDSCs were isolated from the gastrocnemius muscles of SD rats by a modified preplate method and characterized through FACS analysis using various primary antibodies (CD34, Sca-1, CD45 and desmin). The hybrid mixture was prepared by the mixing of PCL microparticles (diameter, 100~200 μm) and MDSCs-containing thermo-sensitive Pluronic (F127/F68 mixture) solution (4.5/5.5, w/v). The hybrid mixture was easily injected through 18G needle into the body and stably remained in the applied site without initial volume decrease, owing to a well-packed structure of PCL particles exhibited in the hybrid mixture. It was observed that the MDSCs were stably grown in the hybrid mixture without severe inflammation and immune reaction. From the results, we recognized that the hybrid mixture can be a good candidate as an injectable bulking agent for the treatment of urinary incontinence, due to their good injectability, volume retention and biocompatibility.

Abstract: Bone Marrow Stromal Cells (BMSCs) have chondrogenesis potential if chondrogenic environments or factors are provided. This study tests the hypothesis that chondrocytes can promote BMSC chondrogenesis at non-chondrogensis site. Porcine BMSCs and auricular chondrocytes were mixed at different ratios and 2.5×107 mixed cells were resuspended in 0.5 ml 30％ Pluronic, and then the mixture was injected into nude mice subcutaneously as experimental groups. Chondrocytes or BMSCs at the same cell number were mixed with 0.5 ml Pluronic and injected respectively as controls. 2.5×107 chondrocytes were mixed and injected as low concentration chondrocyte control. 8 weeks later, all specimens in experimental groups and chondrocyte group formed mature cartilage with abundant collagen II expression. Mature lacuna structures and metachromatic matrices were also observed in these specimens with the same level of GAG contents. Average wet weight of specimens in experimental groups was over 70% of that in chondrocyte group. In contrast, specimens in BMSC group showed mainly fibrous tissue. Only a small amount of cartilage was formed in specimens of low concentration chondrocyte group and the average wet weight was below 30% of that in chondrocyte group. These results demonstrate that chondrocytes can provide chondrogenic microenvironment and thus promote in vivo chondrogenesis of BMSCs at non-chondrogenesis sites. It also indicates that Pluronic is an ideal injectable biomaterial for cartilage tissue engineering.