One-step simultaneous liquid phase exfoliation-induced chirality in graphene and their chirality-mediated microRNA delivery

Graphene (G) has established itself as an exciting prospect for a broad range of applications owing to its remarkable properties. Recent innovations in chiral nanosystems have led to sensors, drug delivery, catalysis, etc. owing to the stereospecific interactions between various nanosystems and enantiomers. As the molecular structure of G itself is achiral introducing chirality in G by simple attachment of a functional group (a chiral ligand) on the G nanosheet may result in more diverse applications. Herein, we demonstrate direct liquid phase exfoliation and chiral induction in G nanosheets abbreviated as l-graphene and d-graphene in the presence of chiral l-tyrosine and d-tyrosine and by applying high-temperature sonication. The obtained exfoliated nanosheets demonstrated stable chirality confirmed by circular dichroism. Fourier transform infrared (FTIR) spectra, Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC) showed functional, structural, morphological, surface, and thermal characteristics of l-graphene and d-graphene. The hemo-compatibility of these chiral graphenes was evaluated for the very first time utilizing human red blood cells. Lastly, for the very first time, an attempt was made to explore enantiomeric binding between chiral l-graphene and d-graphene with microRNA (miR-205) and their possibility towards chirality-mediated gene delivery in prostate cancerous cells.

High-yield graphene produced from the synergistic effect of inflated temperature and gelatin offers high stability and cellular compatibility

The direct exfoliation of graphite (Gr) is highly desirable and feasible compared to conventional processes owing to its non-oxidative, facile and controlled synthesis conditions. Herein, gelatin (gel), a hydrolysed form of collagen, was used as an exfoliant to directly exfoliate Gr. The main advantages of exploring gel as an exfoliant is its easy availability, low cost and high biocompatibility, which alleviate the drawbacks of previous exfoliation methods. The effect of the exfoliation parameters such as temperature, ratio of interacting species and pH of the solution offers a high yield of graphene (G) with the added advantages of good solubility, easy dispersibility and high stability. The temperature elevation caused by the dissipation of sonic waves facilitates a high exfoliation yield. Yield of 4.37 mg mL-1 of G was achieved under the conditions of 7 h sonication at 60 °C, pH 7 and Gr to gel ratio of 60 : 40, whereas yield of 1 mg mL-1 was achieved under sonication at 30 °C. Raman spectroscopy and transmission electron microscopy indicated the production of G sheets with 3-5 layers. The adsorption of gel on the surface of G via π-π interactions offers high stability and retains its inherent crystallinity. The as-synthesized G dispersion exhibits good cyto- and hemocompatibility. Unlike graphene oxide, the G dispersion does not affect RBCs at a relatively high concentration of 10 mg mL-1. These findings offer new avenues for the large-scale production of G and promote its biomedical applications, particularly in scaffold materials and intravenous drug delivery.

Electroconductive Biohybrid Collagen/Pristine Graphene Composite Biomaterials with Enhanced Biological Activity

Electroconductive substrates are emerging as promising functional materials for biomedical applications. Here, the development of biohybrids of collagen and pristine graphene that effectively harness both the biofunctionality of the protein component and the increased stiffness and enhanced electrical conductivity (matching native cardiac tissue) obtainable with pristine graphene is reported. As well as improving substrate physical properties, the addition of pristine graphene also enhances human cardiac fibroblast growth while simultaneously inhibiting bacterial attachment (Staphylococcus aureus). When embryonic-stem-cell-derived cardiomyocytes (ESC-CMs) are cultured on the substrates, biohybrids containing 32 wt% graphene significantly increase metabolic activity and cross-striated sarcomeric structures, indicative of the improved substrate suitability. By then applying electrical stimulation to these conductive biohybrid substrates, an enhancement of the alignment and maturation of the ESC-CMs is achieved. While this in vitro work has clearly shown the potential of these materials to be translated for cardiac applications, it is proposed that these graphene-based biohybrid platforms have potential for a myriad of other applications-particularly in electrically sensitive tissues, such as neural and neural and musculoskeletal tissues.

Facile construction of mechanically tough collagen fibers reinforced by chitin nanofibers as cell alignment templates

Reconstituted collagen fibers with excellent mechanical performance were successfully fabricated with sodium alginate as coagulate and chitin nanofibers as reinforcing filler and applied as a fibroblast alignment templated scaffold.

Functional Graphene Nanomaterials Based Architectures: Biointeractions, Fabrications, and Emerging Biological Applications

Functional graphene nanomaterials (FGNs) are fast emerging materials with extremely unique physical and chemical properties and physiological ability to interfere and/or interact with bioorganisms; as a result, FGNs present manifold possibilities for diverse biological applications. Beyond their use in drug/gene delivery, phototherapy, and bioimaging, recent studies have revealed that FGNs can significantly promote interfacial biointeractions, in particular, with proteins, mammalian cells/stem cells, and microbials. FGNs can adsorb and concentrate nutrition factors including proteins from physiological media. This accelerates the formation of extracellular matrix, which eventually promotes cell colonization by providing a more beneficial microenvironment for cell adhesion and growth. Furthermore, FGNs can also interact with cocultured cells by physical or chemical stimulation, which significantly mediate their cellular signaling and biological performance. In this review, we elucidate FGNs-bioorganism interactions and summarize recent advancements on designing FGN-based two-dimensional and three-dimensional architectures as multifunctional biological platforms. We have also discussed the representative biological applications regarding these FGN-based bioactive architectures. Furthermore, the future perspectives and emerging challenges will also be highlighted. Due to the lack of comprehensive reviews in this emerging field, this review may catch great interest and inspire many new opportunities across a broad range of disciplines.

Multi-functional biomimetic graphene induced transformation of Fe3O4 to ε-Fe2O3 at room temperature

A schematic showing the formation of nanosized ε-Fe₂O₃ in protein–polymer functionalized graphene; the templated IONPs literally coat the graphene nanoflakes. G–IONP colloidal fluid, TEM and MFM micrographs provide visual evidence of the same.