Effect of solubilization of surfactant aggregates on pore structure in gigaporous polymeric particles

Microfluidic preparation of antimicrobial microparticles composed of l-lactide/1,3-dioxolane (co)polymers loaded with quercetin

The resistance of microorganisms against commonly used antibiotics is becoming an increasingly important problem in the food and pharmaceutical industries. Therefore, the development of novel bactericidal agents, as well as the design of drug delivery systems based on materials composed of biocompatible and biodegradable building blocks, has attracted increasing attention. To address this challenge, microparticles composed of l-lactide homopolymer and l-lactide/1,3-dioxolane (co)polymers loaded with quercetin (Q) were fabricated by using a microfluidic technique. This method enables the preparation of homogeneous particles with sizes ranging from 60 to 80 µm, composed of degradable semicrystalline or amorphous (co)polyesters. The microencapsulation of Q in a (co)polymeric matrix enables prolonged release of the antimicrobial agent. The antibacterial properties of the obtained biocompatible microparticles are confirmed by the agar diffusion plate method for various bacterial strains. Therefore, Q-loaded microparticles can have important applications in food preservation as a novel antimicrobial system.

The interaction between dispersed crude oil droplets and particulate matter

In this study, the effect of particulate matter type, temperature, oil type and weathering degree on the interaction between dispersed crude oil droplets and particulate matter was investigated. The increase of total petroleum hydrocarbon (TPH) percentage in oil-particle aggregates (OPAs) could be attributed to the increase of oil polarity or viscosity. For small size particulate matter, there was a fine dependence relationship between the TPH percentage in OPAs and the oil viscosity and the content of polar components, respectively (R2 > 0.7502). And the total organic carbon content also played an important role in the formation of OPAs. The petroleum hydrocarbon extracts of OPAs showed a decrease in short-carbon-chain components and a relative increase in long-carbon-chain compounds. Petroleum hydrocarbon compounds trapped by three types of particulate matter exhibited a similar change tendency, but there was no apparent difference in the residual TPH percentage in water.

Effects of oil dispersants on settling of marine sediment particles and particle-facilitated distribution and transport of oil components

This work investigated effects of three model oil dispersants (Corexit EC9527A, Corexit EC9500A and SPC1000) on settling of fine sediment particles and particle-facilitated distribution and transport of oil components in sediment-seawater systems. All three dispersants enhanced settling of sediment particles. The nonionic surfactants (Tween 80 and Tween 85) play key roles in promoting particle aggregation. Yet, the effects varied with environmental factors (pH, salinity, DOM, and temperature). Strongest dispersant effect was observed at neutral or alkaline pH and in salinity range of 0-3.5wt%. The presence of water accommodated oil and dispersed oil accelerated settling of the particles. Total petroleum hydrocarbons in the sediment phase were increased from 6.9% to 90.1% in the presence of Corexit EC9527A, and from 11.4% to 86.7% for PAHs. The information is useful for understanding roles of oil dispersants in formation of oil-sediment aggregates and in sediment-facilitated transport of oil and PAHs in marine eco-systems.

Design and preparation of porous polymer particles with polydopamine coating and selective enrichment for biomolecules

Pore size distribution of novel gigaporous polymer particles were visualized characterization by laser scanning confocal microscopy, and this gigaporous materials had preferable selective enrichment performance for biomolecules.

The Construction of an Aqueous Two-Phase System to Solve Weak-Aggregation of Gigaporous Poly(Styrene-Divinyl Benzene) Microspheres

Gigaporous poly(styrene-divinyl benzene) microspheres made via the surfactant reverse micelles swelling method had a controllable pore size of 100⁻500 nm. These microspheres had unique advantages in biomacromolecule separation and enzymes immobilization. However, the obtained microspheres adhered to each other in the preparation process. Though the weak aggregation could be re-dispersed easily by mechanical force, it will be difficult to scale up. By analyzing the formation mechanism of the aggregates, a method was presented to rebuild the interface between the internal aqueous channel and the external continuous phase by constructing an aqueous two-phase system (ATPS). Based on the ATPS, the method of emulsification, stirring speed, and surfactant concentration in oil phase were optimized. Under the optimum condition (screen emulsification method, 120 rpm for polymerization and 55% surfactant), the microspheres with a controllable particle size of 10⁻40 μm and a pore size of about 150 nm were obtained. This new method could significantly decrease the weak-aggregation of microspheres.

Engineering of a hybrid polymer-lipid nanocarrier for the nasal delivery of tenofovir disoproxil fumarate: physicochemical, molecular, microstructural, and stability evaluation

PURPOSE

To engineer a hybrid nanocarrier system based on lipid and polymer for the nasal delivery of tenofovir disoproxil fumarate (TDF), and further to investigate its physicochemical, molecular, microstructural, and stability aspects.

METHODS

Nanoparticles were prepared by melt emulsification-probe sonication technique. A 3(2) factorial design was used to identify key formulation variables influencing the characteristics of drug-loaded carrier. FT-IR, mass spectroscopy (MS) and (1)H NMR was used to probe molecular interactions among the components of the system, while the surface morphology was imagined through electron microscopy (TEM and SEM). Thermal analysis and powder X-ray diffraction (PXRD) was used to explore melting and crystallization behavior of drug and the carrier lipid. PLN-9 GEL was studied for its rheology, drug release, ex-vivo permeation, histopathology, and stability.

RESULTS

Batch PLN-9 had size of 239 nm, drug encapsulation of 87.14% and revealed spherical morphology. MS, FT-IR and (1)H NMR established compatibility between the drug (TDF) and the carrier lipid (Lauric acid), while, a strong H-bonding was identified between the amino (-NH2) group of drug and the carboxyl (-COOH) group of pemulen polymer. Thermal analysis confirmed an amorphous TDF within the carrier matrix. PXRD analysis indicated substantial change in the molecular packing and subcell structure of carrier lipid during the PLN processing. PLN-9 GEL had shear thinning rheology, an anomalous type (n>0.5) of drug release and possessed potential to transport TDF across the nasal mucosa with an average flux of 135.36 μg/cm(2)/h.

CONCLUSION

The designed carrier can encapsulate TDF and accentuates its transnasal flux, thus could be used as a carrier for an effective nasal delivery of TDF.

Facile Synthesis of Magnetic Copolymer Microspheres Based on Poly(glycidyl methacrylate-co-N-isopropylacrylamide)/Fe3O4by Suspension Photopolymerization

Magnetic copolymer based on poly(glycidyl methacrylate-co-N-isopropylacrylamide) microspheres was prepared by 2,2-dimethoxy-2-phenylacetophenone- (DMPP-) photo initiated and poly(vinyl alcohol)- (PVA-) stabilized single step suspension photopolymerization. The effect of chemical interaction, morphology, and thermal properties by adding 0.1% w/v Fe3O4in the copolymer was investigated. Infrared analysis (FTIR) showed that (C=C) band disappeared after copolymerization, indicating that the magnetic copolymer microspheres were successfully synthesized and two important bands at 908 cm−1and 1550 cm−1appear. These are associated with the epoxy group stretching of GMA and secondary amide (N–H/C–H) deformation vibration of NIPAAm in magnetic microspheres. The X-ray diffraction (XRD) result proved the incorporation of Fe3O4nanoparticles with copolymer microspheres as peak of Fe3O4was observed. Morphology study revealed that magnetic copolymer exhibited uniform spheres and smoother appearance when entrapped with Fe3O4nanoparticles. The lowest percentage of Fe3O4nanoparticles leached from the copolymer microspheres was obtained at pH 7. Finally, thermal property of the copolymer microspheres was improved by adding a small amount of Fe3O4nanoparticles that has been shown from the thermogram.