Clay microparticles for the enhancement of bone regeneration: in vitro studies.

Humans develop osteoporosis as they age, a disease characterized by the slow and consistent reduction in bone mass and the subsequent risk of fractures. Due to aging, the mesenchymal stem cells within the bone marrow niche, show a shift in differentiation from osteogenesis to adipogenesis. The challenge of osteoporosis treatment is being met with advances in nanotechnology and tissue engineering. In this study , we evaluated the potential of palygorskite clay mineral microparticles for the promotion of the osteogenic differentiation in human mesenchymal stem cells (hMSCs) in vitro. Alkaline phosphatase (ALP) activity and Alizarin red staining showed that osteogenic differentiation of hMSCs is enhanced in the presence of palygorskite clay. Although, gene expression analysis did not reveal upregulation of several osteogenic markers in the presence of the clay microparticles, another interaction mechanism resulted in the enhanced osteogenic differentiation of hMSCs. The charged surfaces of the palygorskite clay particles interact with the stem cells using their high adhesion characteristics, leading to complete bridging, adherence, and enveloping of the stem cells' cadherins and integrins with their environment. This restoration of the adhesion among the stem cells and their environment most probably promotes/restores the osteogenic differentiation of hMSCs. Therefore, palygorskite clay microparticles are a promising candidate for further in vivo studies on bone regeneration.

Nano-clays as Potential Pseudo-antibodies for COVID-19.

Despite several efforts, the development of an effective vaccine for COVID-19 may take a much longer time. Traditional/natural medicine, already experienced by humans, could be an earlier solution. Considering the research team's experience in using nano-clays as high-affinity material for cancer metastasis, melanoma treatment, and bone regeneration, we propose to use these nano-clays for the prevention/treatment of COVID-19. Owing to high affinity, nano-clays would capture the viruses before the latter get engaged with human hACE2. In this study, molecular-level simulations and modeling of the interaction of coronavirus spike and hACE2 proteins were performed with and without nano-clays. The results showed a very high level of affinity/cohesiveness among SARS-CoV-2 spike and nano-clays as compared to the one between the former and hACE2. We premise that these nano-clays since already being used as drug carriers could also be injected as "clays-alone" medicine. Recommendations have also been provided for future in vitro and in vivo studies.