Polymer/silica hybrid hollow nanoparticles with channels and thermo-responsive gatekeepers for drug storage and release

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.

Preparation and Performance of Silica-di-Block Polymer Hybrids for BSA-Resistance Coatings

A series of tem-responsive and protein-resistance property silica-di-block polymers SiO₂-g-PMMA-b-P(PEGMA) hybrids are synthesized with methyl methacrylate (MMA) and poly (ethylene glycol) methyl ether methacrylate (PEGMA) by the surface-initiated atom transfer radical polymerization (SI-ATRP). The morphology in tetrahydrofuran (THF) solution, lower critical solution temperature (LCST), surface morphology, bovine serum albumin (BSA)-resistance property, and thermal stability of nanoparticles were analyzed. The results of ¹H-NMR, GPC, and TEM prove that the silica-di-block hybrids have been obtained. The silica-di-block hybrids shows the LCST (52–64 °C) in aqueous solution. The hybrid films casted by THF present distributed uniform granular bulges and the film surface is relatively smooth (Ra = 15.4 nm ~ 10.5 nm). The results of QCM-D showed that only a small amount of BSA protein(△f = 18.6 ~ 11.8 Hz) was adsorbed on the surface of the films. The result of XPS also demonstrated that only a small amount of BSA protein was absorbed onto the surface of the film (N% = 1.86). The TGA analyses indicate that the thermal decomposition temperature of hybrids is 288 °C. Thus, it is suggested that the hybrids are served as a suitable coating with BSA resistance property and thermal stability.

Temperature Responsive Nanoparticles Based on PEGylated Polyaspartamide Derivatives for Drug Delivery

The temperature responsive PEGylated polyaspartamide derivative, denoted as mPEG-PAAHP, was synthesized by the click reaction. FTIR and ¹H NMR were adopted to characterize and confirm the chemical structures of the obtained mPEG-PAAHPs. The temperature responsive behavior investigated by transmittance and dynamic light scattering showed that some of the obtained mPEG-PAAHPs exhibited obvious temperature responsiveness and could be used to prepare nanoparticles by quickly heating. Drug paclitaxel can be encapsulated into mPEG-PAAHP based nanoparticles with a high encapsulation efficiency up to 99% (corresponding to a drug loading content of around 9.9%). Dynamic light scattering results showed that the PTX-loaded nanoparticles had a mean size around 80 nm (PDI<0.2) and good stability in PBS with 150 mM ionic strength. In vitro cytotoxicity results showed that mPEG-PAAHP did not show any toxicity to HeLa cells, but the PTX-loaded nanoparticles based on mPEG-PAAHP exhibited obvious anti-cancer activity. Thus, the temperature responsive PEGylated polyaspartamide derivative mPEG-PAAHP may be a promising drug delivery system.