Polymeric Micelles Of Poly Research Articles

Systematic investigation to the effects of near-infrared light exposure on polymeric micelles of poly(ethylene glycol)-block-poly(styrene-alt-maleic anhydride) loaded with indocyanine green

The use of diselenide core cross-linked polymeric micelles assisted with indocyanine green (ICG) as a near-infrared (NIR)-responsive drug delivery system was known to be promising in terms of well-controlled release as well as biocompatibility. However, we must note that the effect of NIR exposure is not simply promoting cleavage of Se–Se bonds. In this work, we report a systematic investigation to the effect of NIR light exposure on the polymeric micelles of poly(ethylene glycol)-block-poly(styrene-alt-maleic anhydride) loaded with ICG. Diselenide core-cross-linked micelles and non-cross-linked micelles were prepared for the investigation. The results showed that the reactive oxygen species (ROS) produced from ICG not only reacted with diselenide bonds but also attacked poly(ethylene glycol) chains, resulting in the polymer degradation. The polymer degradation appeared to be continuous even for 36 h after NIR exposure was stopped, as evidenced in DLS, GPC, and TEM measurements. This study provides insight into essential parameters which should be considered in designing ROS-responsive drug delivery systems based on polymeric micelles.

Glucose-installed, SPIO-loaded PEG-b-PCL micelles as MR contrast agents to target prostate cancer cells

Polymeric micelles of poly(ethylene glycol)-block-poly(ɛ-caprolactone) bearing glucose analog encapsulated with superparamagnetic iron oxide nanoparticles (Glu-SPIO micelles) were synthesized as an MRI contrast agent to target cancer cells based on high-glucose metabolism. Compared to SPIO micelles (non-targeting SPIO micelles), Glu-SPIO micelles demonstrated higher toxicity to human prostate cancer cell lines (PC-3) at high concentration. Atomic absorption spectroscopy was used to determine the amount of iron in cells. It was found that the iron in cancer cells treated by Glu-SPIO micelles were 27-fold higher than cancer cells treated by SPIO micelles at the iron concentration of 25 ppm and fivefold at the iron concentration of 100 ppm. To implement Glu-SPIO micelles as a MR contrast agent, the 3-T clinical MRI was applied to determine transverse relaxivities (r2*) and relaxation rate (1/T2*) values. In vitro MRI showed different MRI signal from cancer cells after cellular uptake of SPIO micelles and Glu-SPIO micelles. Glu-SPIO micelles was highly sensitive with the r2* in agarose gel at 155 mM−1 s−1. Moreover, the higher 1/T2* value was found for cancer cells treated with Glu-SPIO micelles. These results supported that glucose ligand increased the cellular uptake of micelles by PC-3 cells with over-expressing glucose transporter on the cell membrane. Thus, glucose can be used as a small molecule ligand for targeting prostate cancer cells overexpressing glucose transporter.

Synthesis of Zinc Borate Hollow Nanospheres Using Polymeric Micelles with Core–Corona Architecture as a Template

Abstract Zinc borate hollow nanospheres with diameter of 30 ± 2 nm have been fabricated by using polymeric micelles of poly(styrene-block-acrylic acid) (PS-b-PAA) as a template. The polymer forms spherical micelles with PS-core and PAA-corona in aqueous solutions, which shows pH-dependent behavior. Zinc borate hollow nanospheres shrink during calcination. FTIR measurements confirm that the template polymer was completely removed during calcination.

Synthesis of hollow silica nanosphere with high accessible surface area and their hybridization with carbon matrix for drastic enhancement of electrochemical property

Hollow silica nanospheres with high accessible surface area have been synthesized by using core-shell-corona polymeric micelle of poly (styrene-b-2-vinyle pyridine-b-ethylene oxide) (PS45kPVP26k-PEO82k) as a template. The size of the template polymeric micelle depends on the pH of the solution, i.e. approximate to 100 nm at pH 7 whereas. approximate to 300 nm at pH 4. The enlarged size of the micelle is possibly due to the protonation of the PVP block, which also serves as reaction sites for silica precursor. The size of the obtained silica nanosphere measured with transmission electron microscope (TEM) is around approximate to 70 nm and shell thickness is approximate to 20 nm. Fourier transformed infrared spectroscopy (FTIR) data confirms that the polymer template is completely removed during calcination. Conductive carbon is doped into the silica nanosphere through glucose solution followed by hydrothermal treatment and pyrolysis. It is found that the electrochemical performance and stability of the silica nanosphere is dramatically enhanced after carbon doping. The combined strategy of the core-shell-corona micelle as template and carbon doping could represent a new platform for the researchers to develop functional nanomaterials.

Controlled Synthesis of Hollow TiO<sub>2</sub> Nanospheres Templated by Polymeric Micelle with Core-Shell-Corona Architecture

Hollow TiO2 nanospheres have been successfully prepared by templating the polymericmicelles of poly (styrene-b-[3-(methacryloylamino)propyl] trimethylammonium chloride- b-ethylene oxide) (PS-b-PMAPTAC-b-PEO), which shows a core-shell-corona structure in aqueous solutions. It was found that, in such system, the wall thickness of the hollow TiO2 is fine tuned by varying the concentration of the TiO2 precursor.

Hydrotropic Polymeric Micelles for Enhanced Paclitaxel Solubility: In Vitro and In Vivo Characterization

The purpose of this investigation was to characterize the in vitro stability and in vivo disposition of paclitaxel in rats after solubilization of paclitaxel into hydrotropic polymeric micelles. The amphiphilic block copolymers consisted of a micellar shell-forming poly(ethylene glycol) (PEG) block and a core-forming poly(2-(4-vinylbenzyloxy)-N,N-diethylnicotinamide) (P(VBODENA)) block. N,N-Diethylnicotinamide (DENA) in the micellar inner core resulted in effective paclitaxel solubilization and stabilization. Solubilization of paclitaxel using polymeric micelles of poly(ethylene glycol)-b-P(D,L-lactide) (PEG-b-PLA) served as a control for the stability study. Up to 37.4 wt % paclitaxel could be loaded in PEG-b-P(VBODENA) micelles, whereas the maximum loading amount for PEG-b-PLA micelles was 27.6 wt %. Thermal analysis showed that paclitaxel in the polymeric micelles existed in the molecularly dispersed amorphous state even at loadings over 30 wt %. Paclitaxel-loaded hydrotropic polymeric micelles retained their stability in water for weeks, whereas paclitaxel-loaded PEG-b-PLA micelles precipitated in a few days. Hydrotropic polymer micelles were more effective than PEG-PLA micelle formulations in inhibiting the proliferation of human cancer cells. Paclitaxel in hydrotropic polymer micelles was administered orally (3.8 mg/kg), intravenously (2.5 mg/kg), or via the portal vein (2.5 mg/kg) to rats. The oral bioavailability was 12.4% of the intravenous administration. Our data suggest that polymeric micelles with a hydrotropic structure are superior as a carrier of paclitaxel due to a high solubilizing capacity combined with long-term stability, which has not been accomplished by other existing polymeric micelle systems.

Polymeric micelles of poly(2-ethyl-2-oxazoline)-block-poly(ε-caprolactone) copolymer as a carrier for paclitaxel

Polymeric micelles based on amphiphilic block copolymers of poly(2-ethyl-2-oxazoline) (PEtOz) and poly(ε-caprolactone) (PCL) were prepared in an aqueous phase. The loading of paclitaxel into PEtOz–PCL micelles was confirmed by 1H-NMR spectra. Paclitaxel was efficiently loaded into PEtOz–PCL micelles using dialysis method, and the loading content of paclitaxel in micelles was in the range 0.5–7.6 wt.% depending on the block composition of block copolymers, organic solvent used in the dialysis, and feed weight ratio of paclitaxel to block copolymer. The higher the content of hydrophobic block in the block copolymers, the higher the loading efficiency of micelles for paclitaxel. When acetonitrile was used as solvent, a higher drug loading efficiency was obtained than with THF. The loading efficiency decreased with increasing feed weight ratio of paclitaxel to block copolymer from 0.1:1 to 0.2:1. The hydrodynamic diameters of paclitaxel-loaded micelles were in the range 18.3–23.4 nm with narrow size distribution. The hemolysis test of PEtOz–PCL performed in vitro indicated that the toxicity of PEtOz–PCLs to lipid membrane was not significant compared with Tween 80, and was comparable to that observed with Cremophore EL. The proliferation inhibition activity of paclitaxel-loaded micelles for KB human epidermoid carcinoma cells was also evaluated in vitro. Paclitaxel-entrapped polymeric micelles exhibited comparable activity to that observed with Cremophore EL-based paclitaxel formulations in inhibiting the growth of KB cells.