Nidhi Varshney

Small peptides are well known for their antimicrobial and various other biological activities. However, their practical implication requires transformation into functional materials that often involve covalent crosslinking or chemical modifications. In contrast, the pristine structure and activity of biomolecules can be preserved in physically crosslinked hydrogels enabling their functional integration. In this work, we report a facile synthetic strategy to fabricate glutathione-based hydrogels utilizing guanosine monophosphate as the gelator enabled by G-Quadruplex formation. The simple physical mixing of two components resulted in a spontaneous transparent and mechanically robust hydrogel. The hydrogels were stable in a wide pH window and showed thermo-reversibility, self-healing, thixotropic and injectable behaviour. The concentration-dependent morphological studies revealed the formation of helical fibrils takes place via protocell-like spherical intermediates. The all-biomolecule hydrogel is biocompatible, and the high water content in the matrix enables them to mimic tissue-like environment further augmenting their suitability for biological applications. In vitro cell studies revealed the potent antiviral activity of the hydrogels against EBV and SARS-CoV-2 viruses. These hydrogels also possess antibacterial activity against both gram-positive and gram-negative bacteria. qRT-PCR, cell proliferation, and EB/AO staining experiments revealed the induced cell apoptosis in gastric cancer cells upon hydrogel treatment. The multimodal bioactivities of the hydrogels can be exploited to design materials for inhibiting microbial propagation and facilitating therapeutic applications to tackle COVID-19-like outbreak situations and minimize health hazards. The viscoelastic and shape-sustaining behaviour of these hydrogels can be potentially utilized to develop antimicrobial coatings on various surfaces.

Naturally occurring liquid-liquid phase separation resulting in biomolecular condensates has inspired the formation of biomolecule based smart materials with multi-dimensional applications. Herein, we report a unique, simple and one step method for the bio-condensation of biomass DNA via non-electrostatic interactions leading to an “all nucleic” hydrogel with excellent mechanical properties. The DNA strands crosslinked with guanosine monophosphate molecules through physical interactions to form helical G-quartet superstructures. The hydrogel shows an efficient encapsulation and sustained release for both hydrophilic and hydrophobic drugs demonstrating the competency as a drug carrier. We believe that this energy efficient and low-cost method represents a new technique for the use of biomass DNA as building blocks for next generation of soft materials.

Vaccine adjuvants are substances that improve the immune capacity of a recombinant vaccine to a great extent and have been in use since the early 1900s; they are primarily short-lived and initiate antigen activity, mainly an inflammatory response. With the developing technologies and innovation, early options such as alum were modified, yet the inorganic nature of major vaccine adjuvants caused several side effects. Outer membrane vesicles, which respond to the stressed environment, are small nano-sized particles secreted by gram-negative bacteria. The secretory nature of OMV gives us many benefits in terms of infection bioengineering. This article aims to provide a detailed overview of bacteria’s outer membrane vesicles (OMV) and their potential usage as adjuvants in making OMV-based vaccines. The OMV adjuvant-based vaccines can be a great benefactor, and there are ongoing trials for formulating OMV adjuvant-based vaccines for SARS-CoV-2. This study emphasizes engineering the OMVs to develop better versions for safety purposes. This article will also provide a gist about the advantages and disadvantages of such vaccines, along with other aspects.