Nanotechnology has acquired an immense recognition in cancer theranostics. Considerable progress has been made in the development of targeted drug delivery system for potent delivery of anticancer drugs to tumor-specific sites. Recently, multifunctional nanomaterials have been explored and used as nanovehicles to carry drug molecules with enhanced therapeutic efficacy. In this present work, graphene oxide quantum dot (GOQD) was conjugated with folic acid functionalized chitosan (FA-CH) to develop a nanocargo (FA-CH-GOQD) for drug delivery in cancer therapy. The synthesized nanomaterials were characterized using Fourier transform infrared spectroscopy, ultraviolet−visible spectroscopy, scanning electron microscopy, transmission electron microscopy, and dynamic light scattering. Photoluminescence spectroscopy was also employed to characterize the formation of GOQD. To validate the efficacy of FA-CH-GOQD as nanocarriers, doxorubicin (DOX) drug was chosen for encapsulation. The in vitro release pattern of DOX was examined in various pH ranges. The drug release rate in a tumor cell microenvironment at pH 5.5 was found higher than that under a physiological range of pH 6.5 and 7.4. An MTT assay was performed to understand the cytotoxic behavior of GOQD and FA-CH-GOQD/DOX. Cytomorphological micrographs of the A549 cell exhibited the various morphological arrangements subject to apoptosis of the cell. Cellular uptake studies manifested that FA-CH-GOQD could specifically transport DOX within a cancerous cell. Further anticancer efficacy of this nanomaterial was corroborated in a breast cancer cell line and demonstrated through 4′,6-diamidino-2-phenylindole dihydrochloride staining micrographs.

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The dynamics of solvation of an excited chromophore, 5-(4″-dimethylaminophenyl)-2-(4'-sulfophenyl)oxazole, sodium salt (DMO), has been explored in confined nanoscopic environments of β-cyclodextrin (βCD) and heptakis(2,6-di- O-methyl)-β-cyclodextrin (DIMEB). Solvation occurs on a distinctly slower time scale (τ ∼ 47 ps, τ ∼ 517 ps) in the host cavity of DIMEB than in that of βCD (τ ∼ 20 ps, τ ∼ 174 ps). The calculated equilibrium solvation response of DMO was characterized by four relaxation components (τ ∼ 0.46-0.48 ps, τ ∼ 3.2-3.4 ps, τ ∼ 32.3-37.7 ps, and τ ∼ 232-485 ps), of which the longer ones (τ, τ) are well-consistent with experiments, whereas the ultrafast components (τ, τ) are unresolved. The observed time constant (τ) within the ∼20-47 ps range arises from slow water molecules in the primary hydration layers of the host CDs and is slower for DIMEB than for βCD presumably due to longer-lived and stronger hydrogen bonds that water forms with the former host relative to the latter. Decomposition of the calculated solvation response of DMO has revealed that conformational fluctuations of the macrocyclic hosts give rise to the observed long-time relaxation component (τ), which is much slower for the inclusion complexes with DIMEB than for those with βCD because of slower conformational dynamics of the former host than that of the latter.

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