Correction: Engineered nanostructures within sol-gel bioactive glass for enhanced bioactivity and modulated drug delivery.

Correction for 'Engineered nanostructures within sol-gel bioactive glass for enhanced bioactivity and modulated drug delivery' by Lakshmi M. Mukundan et al., J. Mater. Chem. B, 2022, https://doi.org/10.1039/d2tb01692c.

Engineered nanostructures within sol-gel bioactive glass for enhanced bioactivity and modulated drug delivery.

The engineering of nanocrystalline phase in amorphous oxide materials such as bioactive glass is emerging as a new area of great technological and scientific interest in the field of biomaterials. This study reports for the first time the infusion of apatite nanocrystals in sol-gel-derived bioactive glass using P123 as the structure-directing agent. The synthesis of a multicomponent 80SiO2-15CaO-5P2O5 bioactive glass material having a hierarchically ordered mesoporous structure with uniformly grown nanocrystals of apatite was achieved through a sono-assisted surfactant-templated sol-gel method. The bulk crystallographic analysis together with microstructural characterizations shows that the nanocrystalline apatite domains are uniformly dispersed as well as embedded along the mesopores. These nanocrystalline domains were found to influence the textural properties. In addition, macroscopic evidence for higher signs of bonelike matrix formation was observed by the biomineralization study in simulated body fluids. Osteostimulatory effects of these glass samples were evident by cultures in a osteogenic and non-osteogenic mediums with human osteosarcoma cells and a higher osteopromotive potential was authenticated by the alkaline phosphatase activity and alizarin red staining. Further, this study shows a new strategy to prolong the drug release period on account of the nanocrystalline phase and hierarchically positioned mesopores, thus making it a better drug delivery matrix as well.

Growth and Regeneration of Osteochondral Cells in Bioactive Niche: A Promising Approach for Osteochondral Tissue Repair.

Functional repair of osteochondral defects caused due to osteoarthritis still remains the greatest challenge in orthopedic therapy. A prospective clinical strategy would be exploring osteochondral tissue engineering possibilities that promote simultaneous regeneration of the articular cartilage layer as well as the underlying subchondral bone. Incorporating the appropriate cues onto the scaffolds for the regeneration of the two contrasting tissues is therefore a demanding function. In the present study, a polymer-ceramic composite scaffolding material consisting of ternary bioactive glass (67.12 SiO2/28.5 CaO/4.38 P2O5 mol %) incorporated into a semi interpenetrating polymer network of hydrophilic-hydrophobic polymer (poly(vinyl alcohol)-polycaprolactone) matrix is prepared and physicochemically characterized. In vitro bioactivity, bone-bonding ability, and biocompatibility evaluation were performed in comparison with the pristine scaffold. The degree of chondrogenic and osteogenic potential of mesenchymal stem cells in both the scaffolds was evaluated by gene expression studies. Although both the scaffolds favored the differentiation to both cell lineages in their respective medium, a higher expression of bone specific genes found with the composite scaffold suggested that this composite scaffold would serve better for osteal layer and henceforth to promote the integration of the osteochondral construct at the defect site.

A new synthesis route to high surface area sol gel bioactive glass through alcohol washing: a preliminary study.

Bioactive glass is one of the widely used bone repair material due to its unique properties like osteoconductivity, osteoinductivity and biodegradability. In this study bioactive glass is prepared by the sol gel process and stabilized by a novel method that involves a solvent instead of the conventional calcinations process. This study represents the first attempt to use this method for the stabilization of bioactive glass. The bioactive glass stabilized by this ethanol washing process was characterized for its physicochemical and biomimetic property in comparison with similar composition of calcined bioactive glass. The compositional similarity of the two stabilized glass powders was confirmed by spectroscopic and thermogravimetric analysis. Other physicochemical characterizations together with the cell culture studies with L929 fibroblast cells and bone marrow mesenchymal stem cells proved that the stabilization was achieved with the retention of its inherent bioactive potential. However an increase in the surface area of the glass powder was obtained as a result of this ethanol washing process and this add up to the success of the study. Hence the present study exhibits a promising route for high surface area bioactive glass for increasing biomimicity.

Retrieval of rat aortic smooth muscle cells as intact cell sheet for regenerative medicine: a cost effective approach using photo polymerization.

Cell-based therapeutics are promising routes for the regeneration of damaged cells and organs. The recovery of cells cultured in vitro for such applications requires the use of proteolytic enzymes which deteriorate its property by disruption of cell-cell and cell-matrix interactions. Intact cell sheets can be retrieved with the use of thermo responsive polymer grafted on to the culture plates. Our study presents the use of photo-polymerization as a simple and inexpensive way to create thermo-responsive culture surfaces for the detachment of intact cell sheet. Poly (N-isopropyl acrylamide) (PNIPAAm) was synthesized by photo-polymerization and characterized by NMR spectroscopy, differential scanning calorimetry and gel permeation chromatography. Thermo-responsive culture dishes were prepared by the coating method and characterized for its thermo-responsive efficacy using FTIR spectroscopy and water contact angle measurements. Atomic force microscopy depicted the thin coating achieved with this method is similar to the conventional grafting method. Suitability for cell culture and cell sheet retrieval was assessed by culturing rat aortic smooth muscle cells in the PNIPAAm coated tissue culture plates. The cells remained viable as evident from the live dead assay and the cell sheet was detached by low temperature treatment. The results demonstrate a versatile method for creating thermo responsive culture surfaces while eliminating the use of expensive radiation sources for the conventional grafting method.