Doping of Carbon Quantum Dots (CDs) in Calcium Phosphate Nanorods for Inducing Ectopic Chondrogenesis via Activation of the HIF-α/SOX-9 Pathway

Calcium phosphate (CaPs)-based nanostructures are mostly known to induce osteogenic differentiation of mesenchymal stem cells (MSCs). However, in the current study, doping of carbon quantum dots into calcium phosphate nanorods (C-CaPs) has been observed to affect the differentiation pathway and enhanced the expression of chondrogenic genes instead of osteogenic ones. Here, we report a microwave-assisted single-step synthesis and doping of carbon dot into calcium phosphate nanorods and their ectopic chondrogenicity in a rodent subcutaneous model. High-resolution transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy studies show that the doping of carbon dots results in p-type semiconductor-like structure formation at the phosphate site of the bioceramic nanostructure, whereas UV–vis absorption shows a drastic drop in band-gap energy, which enhances the molecular oxygen reduction reaction. The cytocompatibility, free radical scavenging property, and fluorescence mi...