A vast amount of research on nanoparticles has been conducted in recent years with versatile applications in the field of drug delivery systems. Nanoparticles are designed as a carrier molecule to deliver drugs in a sustained and stimuli response manner. Recent advances in nanotechnology have led to the development of long circulating nanoparticles with high encapsulation efficiency. This article focuses on the properties such as biocompatibility and biodegradability, which are considered as essential criteria for nanoparticles to be successfully used as a carrier molecule in drug delivery systems. Physicochemical characterization of the nanoparticles such as size and size distribution, surface morphology, zeta potential and surface chemistry has a significant role in the successful formulation and applications in drug delivery systems. Mostly, the size and surface characteristics of nanoparticles enable enhanced intracellular accumulation in tumor cells through passive targeting mechanisms and rapid development of nanoengineering, and aid towards attaining active targeting delivery by co-functionalization of nanoparticles using appropriate targeting ligands. This article reviews the recent progress and development of employing different biocompatible and biodegradable nanoparticles in drug delivery systems. It also briefly recaps the important methods available to evaluate its biocompatibility, the mechanism of biodegradability and clearance properties of NPs.
Biodegradable materials like chitosan (CH) and methoxy polyethylene glycol (mPEG) are widely being used as drug delivery carriers for various therapeutic applications. In this study, copolymer (CH-g-mPEG) of CH and carboxylic acid terminated mPEG was synthesized by carbodiimide-mediated acid amine reaction. The resultant hydrophilic copolymer was characterized by Fourier transform infrared spectroscopy and H NMR studies, revealing its relevant functional bands and proton peaks, respectively. Blank polymeric nanoparticles (B-PNPs) and 5-fluorouracil loaded polymeric nanoparticles (5-FU-PNPs) were formulated by ionic gelation method. Furthermore, folic acid functionalized FA-PNPs and FA-5-FU-PNPs were prepared for folate receptor-targeted drug delivery. FA-5-FU-PNPs were characterized by particle size, zeta potential, and in vitro drug release studies, resulting in 197.7 nm, +29.9 mv, and sustained drug release of 88% in 24 h, respectively. Cytotoxicity studies were performed for FA-PNPs and FA-5-FU-PNPs in MCF-7 cell line, which exhibited a cell viability of 80 and 41%, respectively. In vitro internalization studies were carried out for 5-FU-PNPs and FA-5-FU-PNPs which demonstrated increased cellular uptake of FA-5-FU-PNPs by receptor-mediated transport. Significant (p< .01) reduction (1.5-fold) of reactive oxygen species (ROS) accumulation was observed in lipopolysaccharides-stimulated RAW264.7 macrophages, revealing its potent antioxidant property. From the obtained results, it is concluded that folic acid functionalization of 5-FU-PNPs is an ideal approach for sustained and targeted drug delivery, thereby influencing better therapeutic effect.
Polymerizations of vinyl and methacrylate monomers (2-hydroxyethyl methacrylate, styrene, and methyl methacrylate) were carried out in a choline formate ionic liquid at room temperature without the addition of peroxide-based initiators. Choline formate acted as both an initiator and a solvent and produced high-molecularweight polymers. Gel permeation chromatography and electron paramagnetic resonance measurements indicated that the polymerizations predominantly occurred by a free-radical mechanism. This method of polymerization provides an alternate route to eliminate the use of toxic initiators and solvents.
Carbon materials with elusive 0D, 1D, 2D, and 3D nanostructures and high surface area provide certain emerging applications in electrocatalytic and photocatalytic CO2 utilization. Since carbon possesses high electrical conductivity, it expels the photogenerated electrons from the catalytic surface and can tune the photocatalytic activity in the visible-light region. However, the photocatalytic efficiency of pristine carbon is comparatively low due to the high recombination of photogenerated carriers. Thus, supporting carbon materials, such as graphene, CNTs (Carbon nanotubes), g-C3N4, MWCNs (Multiwall carbon nanotubes), conducting polymers, and its other simpler forms like activated carbon, nanofibers, nanosheets, and nanoparticles, are usually combined with other metal and non-metal nanocomposites to increase the CO2 absorption and conversion. In addition, carbon-based materials with transition metals and organometallic complexes are also commonly used as photocatalysts for CO2 reduction. This review focuses on developing efficient carbon-based nanomaterials for the photoconversion of CO2 into solar fuels. It is concluded that MWCNs are one of the most used materials as supporting materials for CO2 reduction. Due to the multi-layered morphology, multiple reflections will occur within the layers, thus enhancing light harvesting. In particular, stacked nanostructured hollow sphere morphologies can also help the metal doping from corroding.
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