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Graphitic carbon nitride (gCN) has only recently experienced a renaissance in a myriad of domains despite existing as a long-established material described in the chemical literature. Notwithstandi...

Nanoconfinement within flexible interfaces is a key step towards exploiting confinement effects in several biological and technological systems wherein flexible 2D materials are frequently utilized but are arduous to prepare. Hitherto unreported, the synthesis of 2D hydrogel nanosheets (HNSs) using a template- and catalyst-free process is developed representing a fertile ground for fundamental structure-property investigations. In due course of time, nucleating folds propagating along the edges trigger co-operative deformations of HNS generating regions of nanoconfinement within trapped water islands. These severely constricting surfaces force water molecules to pack within the nanoscale regime of HNS almost parallel to the surface bringing about phase transition into puckered rhombic ice with AA and AB Bernal stacking pattern, which was mostly restricted to molecular dynamics studies so far. Interestingly, under high lateral pressure and spatial inhomogeneity within nanoscale confinement, bilayer rhombic ice structures were formed with an in-plane lattice spacing of 0.31 nm. In this work, a systematic exploration of rhombic ice formation within HNS has been delineated using high-resolution transmission electron microscopy, and its ultrathin morphology was examined using atomic force microscopy. Scanning electron microscopy images revealed high porosity while mechanical testing presented young’s modulus of 155 kPa with ∼84% deformation, whereas contact angle suggested high hydrophilicity. The combinations of nanosheets, porosity, nanoconfinement, hydrophilicity, and mechanical strength, motivated us to explore their application as a scaffold for cartilage regeneration, by inducing chondrogenesis of human Wharton Jelly derived mesenchymal stem cells. HNS promoted the formation of cell aggregates giving higher number of spheroid formation and a marked expression of chondrogenic markers (ColI, ColII, ColX, ACAN and S-100), thereby providing some cues for guiding chondrogenic differentiation.

Biophysical properties of the extracellular environment dynamically regulate cellular fates. In this review, we highlight silk, an indispensable polymeric biomaterial, owing to its unique mechanical properties, bioactive component sequestration, degradability, well-defined architectures, and biocompatibility that can regulate temporospatial biochemical and biophysical responses. We explore how the materiobiology of silks, both mulberry and non-mulberry based, affect cell behaviors including cell adhesion, cell proliferation, cell migration, and cell differentiation. Keeping in mind the novel biophysical properties of silk in film, fiber, or sponge forms, coupled with facile chemical decoration, and its ability to match functional requirements for specific tissues, we survey the influence of composition, mechanical properties, topography, and 3D geometry in unlocking the body’s inherent regenerative potential.

Graphene quantum dots (GQDs) are the harbingers of a paradigm shift that revitalize self-assembly of the colloidal puzzle by adding shape and size to the material-design palette. Although self-assembly is ubiquitous in nature, the extent to which these molecular legos can be engineered reminds us that we are still apprenticing polymer carpenters. In this quest to unlock exotic nanostructures ascending from eventual anisotropy, we have utilized different concentrations of GQDs as a filler in free-radical-mediated aqueous copolymerization. Extensive polymer grafting over the geometrically confined landscape of GQDs (0.05%) bolsters crystallization instilling a loom which steers interaction of polymeric cilia into interlaced equilateral triangles with high sophistication. Such two-dimensional (2D) assemblies epitomizing the planar tiling of "Star of David" forming a molecular kagome lattice (KL) without metal templation evoke petrichor. Interestingly, a higher percentage (0.3%) of GQDs allow selective tuning of the interfacial property of copolymers breaking symmetry due to surface energy incongruity, producing exotic Janus nanomicelles (JNMs). Herein, with the help of a suite of characterizations, we delineate the mechanism behind the formation of the KL and JNMs which forms a depot of heightened drug accretion with targeted delivery of 5-fluorouracil in the colon as validated by gamma scintigraphy studies.

Graphical abstract, Highlights • CQDs can act as a multi-site inhibitor by blocking the viral entry, RNA strand synthesis, and replication step. • Triazole functionalized heteroatom co-doped carbon quantum dots (TFH-CQDs) can synergistically exert an intensified antiviral response. • TFH-CQDs may block the viral entry by perturbing various interactions with the host cells. • TFH-CQDs may block the viral enzymes such as helicase and 3CLpro, important for viral replication. • Understanding the receptor recognition mechanism of human coronaviruses with host cells is imperative to elucidate the inhibitory mechanism of TFH-CQDs., Preventing the trajectory of human coronaviruses including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic could rely on the sprint to design a rational roadmap using breakneck strategies to counter its prime challenges. Recently, carbon quantum dots (CQDs), zero-dimensional (0D) carbon-based nanomaterials, have emerged as a fresh antiviral agent owing to their unique physicochemical properties. Additionally, doping instils beneficial properties in CQDs, augmenting their antiviral potential. The antiviral properties of CQDs can be reinforced by heteroatom doping. Bestowed with multifaceted features, functionalized CQDs can interact with the spike protein of the human coronaviruses and perturb the virus-host cell recognition. Recently, triazole derivatives have been explored as potent inhibitors of human coronaviruses by blocking the viral enzymes such as 3-chymotrypsin-like protease (3CLpro) and helicase, important for viral replication. Moreover, they offer a better aromatic heterocyclic core for therapeutics owing to their higher thermodynamic stability. To curb the current outbreak, triazole functionalized heteroatom co-doped carbon quantum dots (TFH-CQDs) interacting with viral cells spanning the gamut of complexity can be utilized for deciphering the mystery of its inhibitory mechanism against human coronaviruses. In this quest to unlock the potential of antiviral carbon-based nanomaterials, CQDs and triazole conjugated CQDs template comprising a series of bioisosteres, CQDs-1 to CQDs-9, can extend the arsenal of functional antiviral materials at the forefront of the war against human coronaviruses.