Carbon nanoforms have emerged as a versatile bioimaging tool. In this work, we have synthesized four different carbon nanoparticles of different dimensions (10–100 nm) and variable fluorescence quantum efficiency (0.007 to 0.37) from four different carbon sources by phosphorus pentoxide‐mediated combustion. The fluorescence quantum efficiency of the resulting self‐passivated nanoparticles has been empirically correlated to the molecular weight and viscosity of the respective carbon source used in the synthesis. The carbon nanoparticles have been found to be significantly biocompatible as observed in the MTS assay. We have applied these biocompatible luminescent carbon nanoparticles as high brightness fluorescent probes for staining human blood platelets with very high target specificity.

The pathogenesis of knee osteoarthritis (OA) is multifaceted and involves the complete joint microenvironment. Despite beneficial evidence of curcumin, the mechanistic insights of nanoemulsified curcumin (n-Cur) delivery to the knee-OA microenvironment are limited. The study aimed to establish localized delivery of curcumin nanoemulsion in the knee joint of OA rats and to examine detailed histopathological changes. n-Cur was prepared using a neutral dietary oil and a surfactant. Adult (5 mo) male SD rats were intra-articularly delivered 40 mg/mL of monoiodoacetate (MIA) to induce OA in the left knee and further treated with n-Cur (30 mg/mL). The effect of n-Cur on macrophage recruitment was evaluated using a co-culture model of CHON 001 and RAW 264.7 cells. In the MIA model, localized delivery of n-Cur significantly reduced knee joint edema and joint space narrowing in the target site. Curcumin ameliorated cartilage degeneration by reducing fibrillation, hypocellularity, and restoring matrix proteoglycan, as evidenced by histology. Reduced synovial inflammation displays the effect of curcumin on the synovium, possibly by lowering the recruitment of macrophages in chemoattractant-stimulated chondrocytes. Thus, curcumin nanoemulsion can act as a chondroprotective agent, modulating the OA microenvironment by reducing joint edema, synovial inflammation, and oxidative stress in the OA model.

In this work, gold-silica plasmonic nanohybrids have been synthesized as model systems which enable tuning of dye fluorescence enhancement/quenching interactions. For each system, a dye-doped silica core is surrounded by a 15 nm spacer region, which in turn is surrounded by gold nanoparticles (GNPs). The GNPs are either covalently conjugated via mercapto silanization to the spacer or encapsulated in a separate external silica shell. The intermediate spacer region can be either dye doped or left undoped to enable quenching and plasmonic enhancement effects respectively. The study indicates that there is a larger enhancement effect when GNPs are encapsulated in the outer shell compared to the system of external conjugation. This is due to the environmental shielding provided by shell encapsulation compared to the exposure of the GNPs to the solvent environment for the externally conjugated system. The fluorescence signal enhancement of the nanohybrid systems was evaluated using a standard HRP-anti-HRP fluorescence based assay platform.