Modified nanoprecipitation method for polysulfone nanoparticles preparation

Engineered Polymer-Supported Biorthogonal Nanocatalysts Using Flash Nanoprecipitation

Transition-metal catalysts (TMCs) effect bioorthogonal transformations that enable the generation of therapeutic agents in situ, minimizing off-target effects. The encapsulation of insoluble TMCs into polymeric nanoparticles to generate "polyzymes" has vastly expanded their applicability in biological environments by enhancing catalyst solubility and stability. However, commonly used precipitation approaches provide limited encapsulation efficiency in polyzyme fabrication and result in a low catalytic activity. Herein, we report the creation of polyzymes with increased catalyst loading and optimized turnover efficiency using flash nanoprecipitation (FNP). Polyzymes with controlled size and catalyst loading were fabricated by tuning the process conditions of FNP. The biological applicability of polyzymes was demonstrated by efficiently transforming a non-toxic prodrug into the active drug within cancer cells.

Exploring Various Techniques for the Chemical and Biological Synthesis of Polymeric Nanoparticles

Nanoparticles (NPs) have remarkable properties for delivering therapeutic drugs to the body’s targeted cells. NPs have shown to be significantly more efficient as drug delivery carriers than micron-sized particles, which are quickly eliminated by the immune system. Biopolymer-based polymeric nanoparticles (PNPs) are colloidal systems composed of either natural or synthetic polymers and can be synthesized by the direct polymerization of monomers (e.g., emulsion polymerization, surfactant-free emulsion polymerization, mini-emulsion polymerization, micro-emulsion polymerization, and microbial polymerization) or by the dispersion of preformed polymers (e.g., nanoprecipitation, emulsification solvent evaporation, emulsification solvent diffusion, and salting-out). The desired characteristics of NPs and their target applications are determining factors in the choice of method used for their production. This review article aims to shed light on the different methods employed for the production of PNPs and to discuss the effect of experimental parameters on the physicochemical properties of PNPs. Thus, this review highlights specific properties of PNPs that can be tailored to be employed as drug carriers, especially in hospitals for point-of-care diagnostics for targeted therapies.

Preparation of Polyetherimide Nanoparticles by a Droplet Evaporation-Assisted Thermally Induced Phase-Separation Method

The droplet evaporation effect on the preparation of polyetherimide (PEI) nanoparticles by thermally induced phase separation (TIPS) was studied. PEI nanoparticles were prepared in two routes. In route I, the droplet evaporation process was carried out after TIPS. In route II, the droplet evaporation and TIPS processes were carried out simultaneously. The surface tension and shape parameters of samples were measured via a drop shape analyzer. The Z-average particle diameter of PEI nanoparticles in the PEI/dimethyl sulfoxide solution (DMSO) suspension at different time points was tested by dynamic light scattering, the data from which was used to determine the TIPS time of the PEI/DMSO solution. The natural properties of the products from both routes were studied by optical microscope, scanning electron microscope and transmission electron microscope. The results show that PEI nanoparticles prepared from route II are much smaller and more uniform than that prepared from route I. Circulation flows in the droplet evaporation were indirectly proved to suppress the growth of particles. At 30 °C, PEI solid nanoparticles with 193 nm average particle size, good uniformity, good separation and good roundness were obtained. Route I is less sensitive to temperature than route II. Samples in route I were still the accumulations of micro and nanoparticles until 40 °C instead of 30 °C in route II, although the particle size distribution was not uniform. In addition, a film structure would appear instead of particles when the evaporation temperature exceeds a certain value in both routes. This work will contribute to the preparation of polymer nanoparticles with small and uniform particle size by TIPS process from preformed polymers.

Comparison of Genotoxicity and Cytotoxicity of Polyvinyl Chloride and Poly(methyl methacrylate) Nanoparticles on Normal Human Lung Cell Lines

High concentrations of micro- and nanoparticles of common plastic materials present in the environment are causing an adverse health impact on living organisms. As a model study, here we report the synthesis and characterization of luminescent polyvinyl chloride (PVC) and poly(methyl methacrylate) (PMMA) nanoparticles and investigate the interaction with normal human lung fibroblast cells (IMR 90) to understand the uptake, translocation, and toxicity of PVC and PMMA nanoparticles. The synthesized particles are in the size range of 120-140 nm with a negative surface potential. The colocalization and uptake efficiency of the nanoparticles were analyzed, and the cytotoxicity assay shows significant reduction in cell viability. Cellular internalization was investigated using colocalization and dynasore inhibitor tests, which showed that the PVC and PMMA nanoparticles enter into the cell via endocytosis. The polymer nanoparticles induced a reduction in viability, decrease in adenosine triphosphate, and increase in reactive oxygen species and lactate dehydrogenase concentrations. In addition, the polymer nanoparticles caused cell cycle arrest at sub-G₁, G₀/G₁, and G2/M phases, followed by apoptotic cell death. Our results reported here are important to the emerging data on understanding the impact of common polymer particles on human health.

Ultrashort Peptide Theranostic Nanoparticles by Microfluidic-Assisted Rapid Solvent Exchange

Ultrashort peptides (USPs), composed of three to seven amino acids, can self-assemble into nanofibers in pure water. Here, using hydrodynamic focusing and a solvent exchange method on a microfluidic setup, we convert these nanofibers into globular nanoparticles with excellent dimensional control and polydispersity. Thanks to USP nanocarriers' structure, different drugs can be loaded. We used Curcumin as a model drug to evaluate the performance of USP nanocarriers as a novel drug delivery vehicle. These nanoparticles can efficiently cross the cell membrane and possess nonlinear optical properties. Therefore, we envisage USP nanoparticles as promising future theranostic nanocarriers.

Controlled Dye Aggregation in Sodium Dodecylsulfate-Stabilized Poly(methylmethacrylate) Nanoparticles as Fluorescent Imaging Probes

Polymer nanoparticles are used extensively in biomedical applications. Poly(methylmethacrylate) (PMMA) nanoparticles obtained via nanoprecipitation were unstable and flocculate or precipitate from solution within a few hours. A simple method to improve the stability of the particles using surfactants at low concentrations was carried out to produce PMMA nanoparticles with long-term stability in water (>6 months). The increased stability was attributed to the incorporation of surfactants inside the polymer particles during nanoprecipitation. The same methodology was also adopted to encapsulate a highly fluorescent hydrophobic perylene tetraester inside the polymer nanoparticles with good stability in water. Because of the presence of the anionic sodium dodecyl sulfate, the particles showed a negative zeta potential of -34.7 mV and an average size of 150 nm. Similarly, the dye-encapsulated polymer nanoparticles showed a zeta potential of -35.1 mV and an average particle size of 180 nm. By varying the concentration of encapsulated dyes inside the polymer nanoparticles, dye aggregation could be controlled, and the fluorescence profiles of the nanoparticles were altered. To understand the uptake and toxicity of the polymer nanoparticles, baby hamster kidney cells were chosen as a model system. The polymer nanoparticles were taken up by the cells within 3 h and were nontoxic at concentrations as high as 100 ppm. The confocal micrographs of the cells revealed localized fluorescence from the polymer nanoparticles around the nucleus in the cytoplasm without the penetration of the nuclear envelope.