Carbon quantum dot tailored calcium alginate hydrogel for pH responsive controlled delivery of vancomycin
Herein, we demonstrate the preparation of highly luminescent carbon quantum dots (CQDs) from Aloe vera leaf gel; in just 2 h at 250 °C through carbonization pathway. The prepared CQDs are structurally characterized with high resolution transmission electron microscopy (HRTEM), hydrodynamic diameter, surface polarity, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman, UV–visible absorption spectrophotometry and fluorescence spectroscopy. The functional carbon nanoparticles are observed as non-cytotoxic materials. The biocompatibility, less cytotoxicity and high aqueous dispersibility of as-synthesized CQDs are motivated to design carbon quantum dot (CQD) tailored calcium alginate (CA) hydrogel films with an aim to controlled delivery of glycopeptides antibiotic vancomycin in the gastrointestinal tract (GI). With CQD, the drug loading capacity of CA/CQD film is increased to 89% from 38% (CA film), whereas; with β-cyclodextrin (β-CD) the vancomycin uptake capacity is increased more, 96%. The release of vancomycin through CA/CQD film is more pronounced at pH 1.5, close to the pH of the stomach and it is found that in pH 1.5 with β-CD, the release rate of vancomycin is lowered, 56% in 120 h. The high drug uptake capacity (96%) and lower release rate (56% in 120 h) of CA/CQD hydrogel film in pH 1.5 with β-CD can be used for its applicability as drug delivery vehicle for controlled release of vancomycin into the stomach region and therefore it can offer a potential option for oral administration of vancomycin.