Microfluidic Synthesis of a Bioactive Metal-Organic Framework for Glucose-Responsive Insulin Delivery.

In the current study, we report the microfluidic synthesis of a metal-organic framework (MOF) for insulin delivery based on the stimulus response of glucose. Insulin- and gold nanoparticle (AuNP)-encapsulated zeolitic imidazolate framework-8 (ZIF-8) was synthesized using a continuous-flow, microfluidic mixing system via a single-step process. Glucose oxidase mimicking the activity of AuNPs was utilized for oxidizing glucose molecules that entered the porous ZIF-8. The AuNPs oxidized glucose into gluconic acid and hydrogen peroxide inside the MOF (Ins-AuNP-ZIF-8). The resulting acidic pH led to the disruption of ZIF-8 and released insulin. Thus, the presence of glucose molecules provided a stimulus for insulin release. The bioactive MOFs were characterized for the presence of functional groups, morphology, crystallinity, size, and elemental confirmation. The presence of fluorescein-5-isothiocyanate-labeled insulin in the composite was confirmed using confocal laser scanning microscopy. The loading of insulin per unit weight of the MOF, determined by size-exclusion-high-performance liquid chromatography, was 77 and 88% in the batch and microfluidic processes, respectively. Drug release studies confirmed the response of the MOFs to glucose, which triggered insulin release. The synthesis process did not affect the characteristics and application of ZIF-8 and Ins-AuNP-ZIF-8. This study involving the facile synthesis of bioactive MOFs offers a sustainable strategy to design stimulus-responsive drug delivery systems and could be exploited for biosensing applications.

Trimethyl chitosan coated palladium nanoparticles as a photothermal agent and its in vitro evaluation in 2D and 3D model of breast cancer cells.

The potential of palladium has been scantily explored in biomedical applications. In the present study, palladium nanoparticles (PdNPs) were synthesized and were successfully coated with trimethyl-chitosan (TMC) to improve their biocompatibility. Coating with TMC improved the nanoparticle accumulation in MDAMB231 breast cancer cells, compared to nanoparticles coated with native chitosan. The TMC coated palladium nanoparticles (TMC/PdNPs) exhibited good biocompatibility and physiological stability, as compared to the plain(uncoated) PdNPs. TMC coated PdNPs resulted in photothermal therapeutic effect, when irradiated with a near-infrared (NIR) laser having the wavelength of 808-nm. The TMC/PdNPs resulted in good cytotoxic effect upon laser treatment in both, 2D monolayers and 3D spheroids of MDAMB231 cells, the latter mimicking the tumor microenvironment. These results clearly indicated that TMC/PdNPs acted as ideal photothermal agents for anti-cancer therapy in combination with a non-invasive near-infrared laser.

Establishment and characterization of lung co-culture spheroids for paclitaxel loaded Eudragit® RL 100 nanoparticle evaluation.

3D cell cultures are regarded as a better and more relevant approach for screening drugs and therapeutics, particularly due to their likeness with the in vivo conditions. Spheroids offer an intermediate platform between in vitro and in vivo models, for conducting tumor-based investigations. In this study, a simple setup was developed for consistent generation of lung co-culture spheroids, which were developed using the cancer cell lines A549, NCI H460, and fibroblast cells WI-38. The potential of these spheroids for evaluating the toxicity of Eudragit® RL 100 nanoparticles (ENP) was explored. Monodisperse ENP, having the size range of 140-200 nm was prepared using the nanoprecipitation method. These were loaded with the poorly water-soluble anticancer drug paclitaxel. The evaluation of toxicity and uptake of drug-loaded ENP revealed that 2D monolayers were more sensitive to treatment than 3D spheroids. Within spheroids, co-cultures were more resistant to the treatment than monocultures. Overall, our findings demonstrated that the lung co-culture spheroids were a suitable model for accelerating the efficacy and toxicity-related investigations of novel drug delivery systems.

Comparison of structural integrity and functional status of corneal endothelium stored in Cornisol and Optisol-GS.

Purpose: To compare the structural integrity and functional status of the donor corneas stored in Cornisol and Optisol-GS. Methods: Fifteen optical grade corneal donor buttons (6 pairs; 3 individual) obtained from Rotary Aravind International Eye Bank were used for the study. The left eye of the paired sample was preserved in Cornisol and the right in Optisol-GS. The three individual buttons were used for the baseline data. The corneas were assessed with slit lamp and specular microscope before and after storage time (7, 10, or 14 days). They were then immunostained for markers of structural integrity (ZO-1, Phalloidin) and functionality (Na+/K+ ATPase). The images were acquired using confocal microscope and analyzed using ImageJ software. Results: There was no difference in the clinical evaluation of the corneal layers between the two media. No marked variation was observed in the immunostaining data with reference to the storage period. Intact cellular integrity was identified in 91% (51%, 98%) [Median (min, max)] of cells in Cornisol and 94% (38%, 98%) cells in Optisol based on ZO-1 staining, comparable to the baseline data [87% (76%, 97%)]. Stress fibers were detected in 42.5% (1%, 88%) cells in Cornisol stored corneas and in 55% (11%, 94%) in Optisol when stained for actin cytoskeleton, which correlated with the presence of epithelial defect before storage and vacuolated endothelial cells after storage. No difference was observed between the two media based on the staining pattern for Na+/K+ ATPase. Conclusion: Cornisol and Optisol-GS are equivalent in maintaining the structural integrity and functionality of the donor corneas.