Investigating the structure of the product of graphene oxide reaction with folic acid and chitosan: density functional theory calculations

Effects of Graphene Oxide (GO) and Reduced Graphene Oxide (rGO) on Green-Emitting Conjugated Copolymer's Optical and Laser Properties Using Simulation and Experimental Studies

The properties of a conjugated copolymer (CP), poly[(9,9-Dioctyl-2,7-divinylenefluorenylene)-alt-co-(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene) (PDVF-co-MEH-PV), were investigated in the presence of graphene oxide (GO) and reduced graphene oxide (rGO) using absorption, fluorescence, laser, and time-resolved spectroscopy. CPs are usually dissolved in low-polar solvents. Although GO does not dissolve well, rGO and PDVF-co-MEH-PV dissolve in chloroform due to their oxygen acceptor sites. Hence, we studied rGO/PDVF-co-MEH-PV (CP/rGO), performing all experiments and simulations in chloroform. We performed simulations on PDVF-co-MEH-PV, approximate GO, and rGO using time-dependent density-functional theory calculations to comprehend the molecular dynamics and interactions at the molecular level. The simulation polymer used a tail-truncated oligomer model with up to three monomer units. The simulation and experimental results were in agreement. Further, the PDVF-co-MEH-PV exhibited fluorescence, laser quenching, rGO-mediated laser blinking, and spectral broadening effects when GO and rGO concentrations increased. The experimental and simulation results were compared to provide a plausible mechanism of interaction between PDVF-co-MEH-PV and rGO. We observed that for lower concentrations of rGO, the interaction did not considerably decrease the amplified spontaneous emissions of PDVF-co-MEH-PV. However, the fluorescence of PDVF-co-MEH-PV was considerably quenched at higher concentrations of rGO. These results could be helpful for future applications, such as in sensors, solar cells, and optoelectronic device design. To demonstrate the sensor capability of these composites, a paper-based sensor was designed to detect ethanol and nitrotoluene. An instrumentation setup was proposed that is cheap, reusable, and multifunctional.

Synthesis and characterization of chitosan/carbon quantum dots/Fe2O3 nanocomposite comprising curcumin for targeted drug delivery in breast cancer therapy

Curcumin, a natural compound with promising anti-cancerous features, suffers from a number of shortcomings such as low chemical stability, bioavailability, and solubility, which impedes its application as an alternative for conventional cancer therapy. In this study, curcumin comprising Fe2O3/Chitosan/CQDs was fabricated through double emulsion method (W/O/W) for the first time to exploit its anticancer features while alleviating its limitation, making this nanocomposite promising in targeted drug delivery. Chitosan, a hydrophilic biopolymer, has incorporated to constitute an adhesive pH-sensitive matrix that can trap the hydrophobic drug resulting in controlled drug release in cancerous environment. Carbon quantum dots render luminescence and water solubility properties, which is favorable for tracing drug release and bio imaging along with enhancement of biocompatibility. Fe2O3 can improve chemical stability and bioavailability in addition to anti-cancerous property. XRD and FTIR analysis confirmed the physical interaction between the drug and fabricated nano composite in addition to chemical bonding between the prepared nano composite. Matrix and spherical structure of the formed drug is corroborated by FESEM analysis. DLS analysis' results determine the mean size of the nano composite at about 227.2 nm and zeta potential result is indicative of perfect stability of the fabricated drug. Various kinetic models for drug release were fitted to experimental data in order to investigate the drug release in which Korsmeyer-Peppas' model was the predominant release system in cancerous environment. In vitro studies through flow cytometry and MTT assay exerted noticeable cytotoxicity effect on MCF-7 cell lines. It can be deduced from these results that curcumin encapsulated with CS/CQDs/Fe2O3 nanocomposites is an excellent alternative for targeted drug delivery.