Release Of Entrapped Protein Research Articles

Sol-gel derived boehmite nanostructures is a versatile nanoplatform for biomedical applications

Alumina is one of the most promising carriers for drug delivery due to the long history of its usage as a vaccine adjuvant. Sol-gel synthesis provides excellent conditions for entrapment of biomolecules within an inorganic cage providing stabilization of proteins under the extremal conditions. In this paper, we show in vitro investigation of monodisperse alumina xerogel nanocontainers (AXNCs) using bovine serum albumin as a model protein entrapped in sol-gel alumina building blocks. Particularly, dose and cell-type dependent cytotoxicity in HeLa and A549 cancer cell lines were employed as well as investigation of antibacterial effect and stability of AXNCs in different biological media. It was shown, that the release of entrapped protein could be provided only in low pH buffer (as in cancer cell cytoplasm). This property could be applied for anticancer drug development. We also discovered boehmite nanoparticles effect on horizontal gene transfer and observed the appearance of antibiotic resistance by means of exchanging of the corresponding plasmid between two different E. coli strains. The present work may help to understand better the influence of AXNCs on various biological systems, such as prokaryotic and eukaryotic cells, and the activity of AXNCs in different biological media.

Redox-responsive minimized fragmentation of three-armed oligo(ethylene glycol) gels for protein release

Redox-responsive drug delivery system (DDS) carriers cross-linked by disulfide bonds have attracted attention, because disulfide bonds can be cleaved in the presence of high glutathione (GSH) concentrations found in cancer cells. In this study, to obtain redox-responsive degradable hydrogels, three-armed oligo(ethylene glycol) (trisOEG) gels were prepared through terminal cross-linking reaction that linked together low-molecular-weight trisOEG molecules via a disulfide bond. The stability of the trisOEG gels was investigated in the presence of a reductant, dithiothreitol (DTT) or reduced GSH, in phosphate buffered saline solution. TrisOEG gels were fragmented by a redox-stimulus, returning the decomposed hydrophilic oligomers to a low-molecular-weight state, similar to the raw material that would be expected to be excreted in vivo by the renal system. In addition, protein-immobilized trisOEG micro-gels were prepared. While no release of entrapped protein from trisOEG micro-gel was observed in the absence of GSH, release of entrapped protein was observed in the presence of GSH at a concentration found in cytoplasm.

Addition of Chitosan to Silicate Cross-Linked PEO for Tuning Osteoblast Cell Adhesion and Mineralization

The addition of chitosan to silicate (Laponite) cross-linked poly(ethylene oxide) (PEO) is used for tuning nanocomposite material properties and tailoring cellular adhesion and bioactivity. By combining the characteristics of chitosan (which promotes cell adhesion and growth, antimicrobial) with properties of PEO (prevents protein and cell adhesion) and those of Laponite (bioactive), the resulting material properties can be used to tune cellular adhesion and control biomineralization. Here, we present the hydration, dissolution, degradation, and mechanical properties of multiphase bio-nanocomposites and relate these to the cell growth of MC3T3-E1 mouse preosteoblast cells. We find that the structural integrity of these bio-nanocomposites is improved by the addition of chitosan, but the release of entrapped proteins is suppressed. Overall, this study shows how chitosan can be used to tune properties in Laponite cross-linked PEO for creating bioactive scaffolds to be considered for bone repair.

Protein‐Release Behavior of Self‐Assembled PEG–β‐Cyclodextrin/PEG–Cholesterol Hydrogels

AbstractThis paper reports on the degradation and protein release behavior of a self‐assembled hydrogel system composed of β‐cyclodextrin‐ (βCD) and cholesterol‐derivatized 8‐arm star‐shaped poly(ethylene glycol) (PEG8). By mixing βCD‐ and cholesterol‐derivatized PEG8 (molecular weights 10, 20 and 40 kDa) in aqueous solution, hydrogels with different rheological properties are formed. It is shown that hydrogel degradation is mainly the result of surface erosion, which depends on the network swelling stresses and initial crosslink density of the gels. This degradation mechanism, which is hardly observed for other water‐absorbing polymer networks, leads to a quantitative and nearly zero‐order release of entrapped proteins. This system therefore offers great potential for protein delivery.