Physically stimulus-responsive nanoparticles for therapy and diagnosis.

Nanoparticles offer numerous advantages in various fields of science, particularly in medicine. Over recent years, the use of nanoparticles in disease diagnosis and treatments has increased dramatically by the development of stimuli-responsive nano-systems, which can respond to internal or external stimuli. In the last 10 years, many preclinical studies were performed on physically triggered nano-systems to develop and optimize stable, precise, and selective therapeutic or diagnostic agents. In this regard, the systems must meet the requirements of efficacy, toxicity, pharmacokinetics, and safety before clinical investigation. Several undesired aspects need to be addressed to successfully translate these physical stimuli-responsive nano-systems, as biomaterials, into clinical practice. These have to be commonly taken into account when developing physically triggered systems; thus, also applicable for nano-systems based on nanomaterials. This review focuses on physically triggered nano-systems (PTNSs), with diagnostic or therapeutic and theranostic applications. Several types of physically triggered nano-systems based on polymeric micelles and hydrogels, mesoporous silica, and magnets are reviewed and discussed in various aspects.

In vitro DNA plasmid condensation and transfection through pH-responsive nanohydrogel.

Nanohydrogels (NHs) with the benefits of both nanomaterials and hydrogels unlock novel opportunities and applications in biomedicine. Nowadays, cationic NHs have attracted attention in the delivery of genetic materials into cells. Herein, by using reversible addition-fragmentation chain transfer method, an NH-based poly(hydroxyethyl methacrylate-co-N,N-dimethylaminoethyl methacrylate) and cross-linked by poly(ethylene glycol)diacrylate with pH responsiveness character was developed. Several techniques including nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and gel permeation chromatography confirmed the success in the synthesis. The pH responsiveness of the developed NH was shown by transmission electron microscopy and dynamic light scattering technique. The average sizes of NHs in the normal (7.4) and acidic pH (5.5) were 180 and 390 nm, respectively. The ability of the developed NH to condense genetic materials was checked using gel retardation assay with different ratios of NH and pCMV6-IRES-AcGFP, as a plasmid encoding green fluorescence protein. Results of gel retardation assay showed a decreasing trend in plasmid electrophoretic mobility with the increase in the NH concentration. The NH/plasmid complexes were stopped completely at the ratio of 5 and the plasmid band vanished at the ratio of 10. The quantitative and qualitative results of the cell transfection experiment using different ratios of NH/plasmid showed the ability of NH to carry plasmid molecules into the cancerous cells. The best transfection efficiency was observed by nanohydrogel/plasmid weight ratio of 10, while other ratios including 2, 5 and 20 showed 0.8, 10 and 12% of transfection efficiency, respectively. All the assessed factors showed that NH has the potential to be considered as an efficient gene delivery vehicle.

Thermo-responsive poly(N-isopropylacrylamide)-block-poly(ionic liquid) of pyridinium sulfonate immobilized Pd nanoparticles in C-C coupling reactions.

A thermo-responsive poly(N-isopropylacrylamide)-block-poly(ionic liquid) (PNIPAM-b-PIL) of pyridinium-type was prepared. Initially, controlled synthesis of PNIPAM was performed via RAFT method. Subsequently, PNIPAM as macromolecular chain transfer agent (macro-CTA) was used for fabrication of PNIPAM-b-PIL through reaction with a synthesized IL monomer i.e. 4-vinyl pyridinium propane sulfonate. The Pd catalyst was produced throughout palladium nanoparticles' anchoring into this block copolymer. The catalyst was characterized using ICP, FT-IR, NMR, UV-Vis, TGA, XRD, SEM and EDX techniques. The catalyst's TEM image proved nearly fine dispersion of PdNPs with negligible agglomeration. The catalyst was used in the production of a variety of substituted alkenes and biaryl compounds (Heck and Suzuki coupling) in organic and aqueous media and under solvent free conditions. Additionally, the results signified extreme reusability of the catalyst with a simple recycling procedure.