Adhesion protein adsorption and bone cell growth on carbon nanotube composite materials

Bone growth on nano-structured materials is of paramount importance for designing better orthopedic prostheses. We have demonstrated here that surface energies and nano scale roughness are indeed important factors for determining adsorption of an important adhesion protein, fibronectin, and subsequent growth of bone forming cells, osteoblasts, on carbon nanotube composite materials. For more meaningful and relevant quantification of surface roughness, effective roughness and normalized fibronectin adsorption was introduced. The results demonstrate that normalized fibronectin adsorption is strongly correlated with the effective roughness of surfaces. Rougher surfaces were shown to have higher surface energies, which also leads to greater adsorption. Most importantly, observed fibronectin adsorption is analyzed via a linear function of surface energy and surface roughness that describes the independent contributions of chemistry and physical roughness for fibronectin adsorption. Furthermore, micro-aligned patterns of carbon nanotubes/nanofibers on plastic substrates of polycarbonate urethane or poly-lactic-co-glycolic acid were developed to determine subsequent cell adhesion and long term functioning of osteoblasts. Results showed direct evidence of both selective adhesion of osteoblasts and accelerated deposition of subsequent calcium phosphate crystals on micro-aligned patterns of carbon nanotube composite materials. All experimental and theoretical analyses supported the importance of surface energy in terms of nano-roughness in mediating fibronectin adsorption, osteoblast adhesion, and even differentiation of osteoblasts. In such a manner, this quantitative study provides promising evidence for maximizing the surface responses for adhesion proteins and subsequent cell functioning by controlling surface properties in the nanoscale, providing direct information for designing better orthopedic materials

Mucosal delivery of nanovaccine strategy against COVID-19 and its variants

Despite the global administration of approved COVID-19 vaccines (e.g., ChAdOx1 nCoV-19®, mRNA-1273®, BNT162b2®), the number of infections and fatalities continue to rise at an alarming rate because of the new variants such as Omicron and its subvariants. Including COVID-19 vaccines that are licensed for human use, most of the vaccines that are currently in clinical trials are administered via parenteral route. However, it has been proven that the parenteral vaccines do not induce localized immunity in the upper respiratory mucosal surface, and administration of the currently approved vaccines does not necessarily lead to sterilizing immunity. This further supports the necessity of a mucosal vaccine that blocks the main entrance route of COVID-19: nasal and oral mucosal surfaces. Understanding the mechanism of immune regulation of M cells and dendritic cells and targeting them can be another promising approach for the successful stimulation of the mucosal immune system. This paper reviews the basic mechanisms of the mucosal immunity elicited by mucosal vaccines and summarizes the practical aspects and challenges of nanotechnology-based vaccine platform development, as well as ligand hybrid nanoparticles as potentially effective target delivery agents for mucosal vaccines