Shedding light on the use of graphene oxide-thiosemicarbazone hybrids towards the rapid immobilisation of methylene blue and functional coumarins

Coumarins, methylene blue derivatives, as well as related functional organic dyes have become prevalent tools in life sciences and biomedicine. Their intense blue fluorescence emission makes them ideal agents for a range of applications, yet an unwanted facet of the interesting biological properties of such probes presents a simultaneous environmental threat due to inherent toxicity and persistence in aqueous media. As such, significant research efforts now ought to focus on their removal from the environment, and the sustainable trapping onto widely available, water dispersible and processable adsorbent structures such as graphene oxides could be advantageous. Additionally, flat and aromatic bis(thiosemicarbazones) (BTSCs) have shown biocompatibility and chemotherapeutic potential, as well as intrinsic fluorescence, hence traceability in the environment and in living systems. A new palette of graphene oxide-based hierarchical supramolecular materials incorporating BTSCs were prepared, characterised, and reported hereby. We report on the supramolecular entrapping of several flat, aromatic fluorogenic molecules onto graphene oxide on basis of non-covalent interactions, by virtue of their structural features with potential to form aromatic stacks and H-bonds. The evaluations of the binding interactions in solution by between organic dyes (methylene blue and functional coumarins) and new graphene oxide-anchored Zn(ii) derivatised bis(thiosemicarbazones) nanohybrids were carried out by UV-Vis and fluorescence spectroscopies.

PVA-Based Nanofibers Containing Chitosan Modified with Graphene Oxide and Carbon Quantum Dot-Doped TiO2 Enhance Wound Healing in a Rat Model

Electrospun nanofibrous constructs based on nanoparticles and biopolymers have recently been used in tissue engineering because of their similarity to the extracellular matrix in nature. In this study, electrospun chitosan-carbon quantum dot-titanium dioxide-graphene oxide (CS-CQD-TiO₂-GO) nanofibrous mats were synthesized for use as wound dressings by the electrospinning method. To increase the biodegradation rate and water resistance, the fabricated nanofibrous mats were cross-linked. SEM images showed a uniform and coherent structure of CS-CQD-TiO₂-GO nanocomposites and CS-CQD-TiO₂-GO electrospun nanofibers mats. FTIR analysis, XRD pattern, SEM mapping, and EDS spectrum demonstrate the accuracy of the synthesis as well as the elemental and chemical structure of the nanofibrous mat. The water contact angle indicated that the nanofibrous mat had a hydrophilic property, which is essential for controlling wound exudates. The tensile strength and elongation tests showed that the nanofibrous mat has suitable mechanical properties for wound dressing, including significant flexibility and strength. Interestingly, antimicrobial testing illustrated that the fabricated nanofibrous mat had antibacterial activity against Gram-negative and Gram-positive bacteria. Appropriate cell viability and cytocompatibility of treated mouse fibroblast NIH3T3 cells with the nanofibrous mat were determined using an MTT assay. The animal study results confirmed the proper potential of the nanofibrous mat in wound dressing applications.

Chitosan/carbon quantum dot/aptamer complex as a potential anticancer drug delivery system towards the release of 5-fluorouracil

Nowadays, nanotechnology contributes diminishing side effects rather than traditional therapeutic methods like chemotherapy. Thus, designing a biocompatible specific targeted nanocarrier with prolonged half-life and enhanced bio-availability using simultaneous cell imaging seems urgent. To meet this demand, 5-fluorouracil-chitosan‑carbon quantum dot-aptamer (5-FU-CS-CQD-Apt) nanoparticle was successfully synthesized for specific targeted delivery of 5-FU anti-cancer drug used in breast cancer treatment and this was done by following facile water-in-oil (W/O) emulsification method. Physicochemical properties were characterized and high drug loading and entrapment efficiency were achieved. The average size and zeta potential of the nanoparticle were 122.7 nm and + 31.2 mV, respectively. According to the in-vitro drug release profile, 5-FU-CS-CQD-Apt released the drug in a controlled manner. MTT assay, flow cytometry, fluorescence microscopy, and gene expression results demonstrated that the blank nanoparticle was biocompatible, and 5-FU-CS-CQD-Apt could kill tumor cells efficiently. Bcl-2/Bax ratio was decreased after 5-FU-CS-CQD-Apt treatment in MCF-7 cells. It was concluded that 5-FU-CS-CQD-Apt could be used as a potential nanocarrier in breast cancer treatment.

Facile Approach to Prepare rGO@Fe3O4 Microspheres for the Magnetically Targeted and NIR-responsive Chemo-photothermal Combination Therapy

Near-infrared (NIR)-light responsive graphene have been shown exciting effect on cancer photothermal ablation therapy. Herein, we report on the preparation of Fe₃O₄-decorated hollow graphene microspheres (rGO@Fe₃O₄) by a facile spray drying and coprecipitation method for the magnetically targeted and NIR-responsive chemo-photothermal combination therapy. The microspheres displayed very high specific surface area (~ 120.7 m² g^-1) and large pore volume (~ 1.012 cm³ g^-1), demonstrating distinct advantages for a high loading capacity of DOX (~ 18.43%). NIR triggered photothermal effect of the rGO@Fe₃O₄ microspheres responded in an on-off manner and induced a high photothermal conversion efficiency. Moreover, The Fe₃O₄ on the microspheres exhibited an excellent tumor cells targeting ability. The chemo-photothermal treatment based on rGO@Fe₃O₄/DOX showed superior cytotoxicity towards Hela cells in vitro. Our studies indicated that rGO@Fe₃O₄/DOX microcapsules have great potential in combined chemo-photothermal cancer treatment.

Antibacterial properties of a bacterial cellulose CQD-TiO2 nanocomposite

Antibacterial dressing can prevent the occurrence of many infections of wounds. Bacterial cellulose (BC) has the ability to carry and transfer the medicine to achieve a wound healing bandage. In this study, Carbon Quantum Dots-Titanium dioxide (CQD-TiO₂) nanoparticles (NP) were added to BC as antibacterial agents. FTIR Spectroscopy illuminated that NPs were well-bonded to BC. Interestingly, MIC test proved that BC/CQD-TiO₂ nanostructure (NS) has anti-bacterial properties against Staphylococcus aureus. The findings indicated that, CQD-TiO₂ NPs have stronger antibacterial properties with better tensile strength compared to CQD NPs, in a concentration-dependent manner. Toxicity of CQD-TiO₂ NPs on human L929 fibroblast cells was also evaluated. Most importantly, the results of the scratch test indicated that the NS was effective in wound healing in L929 cells. The approach in this study may provide an alternative to make an antibacterial wound dressing to achieve an effective drug-based bandage.

A magnetic nanoparticle functionalized reduced graphene oxide-based drug carrier system for a chemo-photodynamic cancer therapy

The proposed work shows the dual therapeutic impact of an external stimulus responsive CPT loaded MrGO-AA-g-4-HC carrier system for cancer treatments.

Optimizing the nanostructure of graphene oxide/silver/arginine for effective wound healing

In this study, we introduce a novel graphene oxide/silver/arginine (GO/Ag/Arg) nanohybrid structure, which can act as an angiogenesis promoter and provide antibacterial nanostructure for improving the wound healing process. GO/Ag nanostructure has been optimized in terms of the GO/Ag mass ratio and pH values using central composite design and the response surface method to increase the Ag loading efficiency. Then, Arg was chemically introduced to the surface of GO/Ag nanostructure. Electrospun polycaprolactone (PCL)-GO/Ag/Arg nanocomposite was successfully fabricated and characterized. The synthesized nanocomposite demonstrated not only a great antibacterial effect on both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacterial species, but appropriate biocompatibility against L929 fibroblastic cell lines. The results demonstrated that the preparation of the PCL-GO/Ag/Arg nanocomposite at a concentration of 1.0 wt% GO/Ag/Arg possessed the best biological and mechanical features. In vivo experiments also revealed that the use of optimized PCL-GO/Ag/Arg nanocomposite, after 12 d of treatment, led to significant increase in the healing process and also regeneration of the wound via reconstruction of a thickened epidermis layer on the wound surface, which was confirmed by histological analysis. In conclusion, the proposed approach can introduce a novel notion for preparing antibacterial material that significantly promotes angiogenesis.