Additive-free Aqueous Dispersions of Two-Dimensional Materials with Glial Cell Compatibility and Enzymatic Degradability.

Water-dispersible two-dimensional (2D) materials are desirable for diverse applications. Aqueous dispersions make processing safer and greener and enable evaluation of these materials on biological and environmental fronts. To evaluate the effects of 2D materials with biological systems, obtaining dispersions without additives is critical and has been a challenge. Herein, a method was developed for obtaining additive-free aqueous dispersions of 2D materials like transition metal dichalcogenides and hexagonal boron nitride (h-BN). The nanosheet dispersions were investigated through spectroscopic and microscopic methods, along with the role of size on stability. The aqueous media enabled investigations on cytocompatibility and enzymatic degradation of molybdenum disulphide (MoS2 ) and h-BN. Cytocompatibility with mixed glial cells was observed up to concentrations of 100 µg mL-1 , suggesting their plausible usage in bioelectronics. Besides, biodegradation using human myeloperoxidase (hMPO) mediated catalysis was investigated through Raman spectroscopy and electron microscopy. The findings suggested that additive-free 2H-MoS2 and h-BN were degradable by hMPO, with 2H-phase exhibiting better resistance to degradation than the 1T-phase, while h-BN exhibited slower degradation. The findings pave a path for incorporating 2D materials in the burgeoning field of transient bioelectronics.

Design of tunable gelatin-dopamine based bioadhesives.

Bioadhesives have a potential to modulate the wound closure process with significant biological outcomes. However, none of the currently commercialized adhesives are satisfactory in their performance. It is a challenging task to develop an adhesive system that can work on wet surface and enhances tissue repair and closure. In this study, we have fabricated a series of gelatin-dopamine (Gel-dop) conjugates and studied their adhesive properties after being chemically crosslinked using sodium periodate. The designed material was assessed for its adhesive properties including tensile, lap shear and peeling study by varying the degree of dopamine substitution. It was observed that the adhesive property has a direct correlation with increase in dopamine content until reaching a maximum and then a subsequent decrease. We tested the adhesive strength of the different formulations by varying the degree of substitution and compared against fibrin glue, which is considered as the gold standard of adhesives. The formulation with a moderate substitution degree demonstrated the optimal adhesive property than those formulations with lower and larger substitution degree. Further, the in vitro cytotoxicity study showed that this tunable Gel-dop adhesives are to non-cytotoxic, indicating a potential use in clinic applications. This study illustrates that adhesiveness can be regulated by changing the degree of dopamine substitution.

Biomimetic Lipid-Based Nanosystems for Enhanced Dermal Delivery of Drugs and Bioactive Agents.

Clinical utility of conventional oral therapies is limited by their inability to deliver therapeutic molecules at the local or targeted site, causing a variety of side effects. Transdermal delivery has made a significant contribution in the management of skin diseases with enhanced therapeutic activities over the past two decades. In the modern era, various biomimetic and biocompatible polymer-lipid hybrid systems have been used to augment the transdermal delivery of therapeutics such as dermal patches, topical gels, iontophoresis, electroporation, sonophoresis, thermal ablation, microneedles, cavitational ultrasound, and nano or microlipid vesicular systems. Nevertheless, the stratum corneum still represents the main barrier to the delivery of vesicles into the skin. Lipid based formulations applied to the skin are at the center of attention and are anticipated to be increasingly functional as the skin offers many advantages for the direction of such systems. Accordingly, this review provides an overview of the development of conventional to advanced biomimetic lipid vesicles for skin delivery of a variety of therapeutics, with special emphasis on recent developments in this field including the development of transferosomes, niosomes, aquasomes, cubosomes, and other new generation lipoidal carriers.

Fluorescent Biotin Analogues for Microstructure Patterning and Selective Protein Immobilization.

Benzyl substitution on ureido nitrogens of biotin led to manifestation of aggregation-induced emission, which was studied by steady-state fluorescence, microscopy, and TD-DFT, providing a rationale into the observed photophysical behavior. Besides exhibiting solvatochromism, the biotin derivatives revealed emission peaks centered at ∼430 and 545 nm, which has been attributed to the π-π stacking interactions. Our TD-DFT results also correlate the spectroscopic data and quantify the nature of transitions involved. The isothermal titration calorimetry data substantiates that the binding of the biotin derivatives with avidin are pretty strong. These derivatives on lithographic patterning present a platform for site specific strept(avidin) immobilization, thus opening avenues for potential applications exploiting these interactions. The fluorescent biotin derivatives can thus find applications in cellular biology and imaging.

Self-Assembly of Tyrosine into Controlled Supramolecular Nanostructures.

In the context of designing novel amino acid nanostructures, the capacity of tyrosine alone to form well-ordered structures under different conditions was explored. It was observed that Tyr can self-assemble into well-defined morphologies when deposited onto surfaces for transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. The influence of various parameters that can modulate the self-assembly process, including concentration of the amino acid, aging time, and solvent, was studied. Different supramolecular architectures, including nanoribbons, branched structures, and fern-like arrangements were also observed.

Graphene-based nanomaterials for nanobiotechnology and biomedical applications.

Graphene family nanomaterials are currently being extensively explored for applications in the field of nanotechnology. The unique intrinsic properties treasured in their simple molecular design and their ability to work in coherence with other existing nanomaterials make graphene family nanomaterials the most promising candidates for different types of applications. This review highlights the scope and utility of these multifaceted nanomaterials in nanobiotechnology and biomedicine. In a tandem approach, this review presents the smooth inclusion of these nanomaterials into existing designs for creating efficient working models at the nanoscale level as well as discussing their broad future possibilities.