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A wide array of biomedical applications, extending from the fabrication of implant materials to targeted drug delivery, can be attributed to polymers. The utilization of chemical monomers to form polymers, such as polypropylene, polystyrene, and polyethylene, can provide high mechanical stability to them and they can be utilized for diverse electronic or thermal applications. However, certain chemical-based synthetic polymers are toxic to humans, animals, plants, and microbial cells. Thus, biopolymers have been introduced as an alternative to make them utilizable for biomedical applications. Even though biopolymers possess beneficial biomedical applications, they are not stable in biological fluids and exhibit toxicity in certain cases. Recent advances in nanotechnology have expanded its applicational significance in various domains, especially in the evolution of biopolymers to transform them into nanoparticles for numerous biomedical applications. In particular, biopolymers are fabricated as nanofibers to enhance their biological properties and to be utilized for exclusive biomedical applications. The aim of this review is to present an overview of various biopolymer nanofibers and their distinct synthesis approaches. In addition, the medical applications of biopolymer nanofibers, including antimicrobial agents, drug delivery systems, biosensor production, tissue engineering, and implant fabrication, are also discussed.

Graphical abstract Numerous viral infections are common among humans, and some can lead to death. Even though conventional antiviral agents are beneficial in eliminating viral infections, they may lead to side effects or physiological toxicity. Silver nanoparticles and nanocomposites have been demonstrated to possess inhibitory properties against several pathogenic microbes, including archaea, bacteria, fungi, algae, and viruses. Its pronounced antimicrobial activity against various microbe-mediated diseases potentiates its use in combating viral infections. Notably, the appropriated selection of the synthesis method to fabricate silver nanoparticles is a major factor for consideration as it directly impacts antiviral efficacy, level of toxicity, scalability, and environmental sustainability. Thus, this article presents and discusses various synthesis approaches to produce silver nanoparticles and nanocomposites, providing technological insights into selecting approaches to generate antiviral silver-based nanoparticles. The antiviral mechanism of various formulations of silver nanoparticles and the evaluation of its propensity to combat specific viral infections as a potential antiviral agent are also discussed.

Hydrogels are highly versatile and widely applicable materials within various scientific, technological, and food sectors. Alginate and gelatin hydrogels, along with their crafted variations, are possibly the most common ones. However, the ionic crosslinking of alginate-Ca++ is a different gelation mechanism than the physical crosslinking of gelatin. In this work, we prepare alginate-Ca++ hydrogels using individual layer gelation and experimentally evaluate LAOS rheological behavior. We apply shear-stress decomposition using the MITlaos software and obtain the elastic and viscous contributions within the nonlinear response of the individual alginate-Ca++ layer. We compare these results with the nonlinear responses of the gelatin-alginate ex situ individual layer. The strain-sweep patterns are similar, with loss modulus overshoot. The applied shear can destroy the larger-scale structural units (agglomerate/aggregates), resulting in analogous patterns. However, the critical strain points are different. Based on the shear-thickening ratio T of the LAOS analysis, it can be assumed that the common feature of ex situ preparation, i.e., gelation as individual layers, provides a matching bulk microstructure, as the hydrogels differ significantly at a molecular-binding level.

A readily distinguishable and indigenous member of the plant kingdom in the Indian subcontinent is the 'drumstick tree', i.e. Moringa oleifera Lam. In addition to India, this drought-tolerant and rapidly evolving tree is currently extensively disseminated across the globe, including subtropical and tropical areas. The plant boasts a high nutritional, nutraceutical and therapeutic profile, mainly attributing to its significant repertoire of the biologically active components in different parts: protein, flavonoids, saponins, phenolic acids, tannin, isothiocyanate, lipids, minerals, vitamins, amongst others. M. oleifera seeds have been shown to elicit a myriad of pharmacological potential and health benefits, including: antimicrobial, anticancer, antidiabetic, antioxidant, antihypertensive, anti-inflammatory and cardioprotective properties. Additionally, the seed cakes obtained from post-extraction process are utilized for: coagulation, flocculation and sedimentation purposes, benefiting effluent management and the purification of water, mainly because of their capability in eliminating microbes and organic matter. Despite the extraordinary focus on other parts of the plant, especially the foliage, the beneficial aspects of the seeds have not been sufficiently highlighted. The health benefits of bioactive components in the seeds are promising and demonstrate enough potential to facilitate the development of functional foods. In this review, we present a critical account of the types, characteristics, production and isolation of bioactive components from M. oleifera seeds. Furthermore, we appraise the: pharmacological activities, cosmetic, biodiesel, lubricative, modern farming, nutritive and wastewater treatment applications of these functional ingredients. We infer that there is a need for further human/clinical studies and evaluation, despite their health benefits. Additionally, the safety issues need to be adequately clarified and assessed, in order to establish a conventional therapeutic profile.

We study buffered aqueous solutions of deoxyribonucleic acid isolated from bacteriophage lambda (λ-DNA) at shear rates up to 105 s−1. The shear rates are accessed with a narrow-gap rheometer at gap widths down to 20 μm. At lower shear rates, our data merge with the literature values. At high shear rates, the viscosity levels off into an infinite-shear viscosity plateau. Hence, the viscosity functions of buffered aqueous DNA solutions are now available for the entire shear-rate range from the first Newtonian plateau to that of infinite-shear viscosity. The latter hardly differs from the solvent viscosity. For the normal-stress differences, we observe a power-law dependence on the shear rate close to previous findings up to shear rates of about 104 s−1. Beyond this shear-rate range, we observe a stepwise change with the shear rate. By means of agarose gel electrophoresis, we confirm that the λ-DNA is not fragmented during our rheometric study at high shear rates. Yet, at the highest shear rates studied, shear-induced changes in the DNA to structures not being able to travel through the gel appear.

The current work investigates the suitability of seven contestant formulations toward the development of a green commercial lipstick model incorporated with vitamin D3. We analytically examined the...

The extensional rheology of polymeric liquids has been extensively examined through experiments and theoretical predictions. However, a systematic study of the extensional rheology of polymer solutions in the semidilute regime, in terms of examining the effects of concentration and molecular weight, has not been carried out so far. Prior studies of the shear rheology of semidilute polymer solutions have demonstrated that their behaviour is distinctively different from that observed in the dilute and concentrated regimes. This difference in behaviour is anticipated to be even more pronounced in extensional flows. In this work, the extensional rheology of linear, double-stranded DNA molecules, spanning an order of magnitude of molecular weights (25 to 289 kilobasepairs) and concentrations (0.03 to 0.3 mg/ml), has been investigated. DNA solutions are now used routinely as model polymeric systems due to their near-perfect monodispersity. Measurements have been carried out with a filament stretching rheometer since it is the most reliable method for obtaining an estimate of the elongational stress growth of a polymer solution. Transient and steady-state uniaxial extensional viscosities of DNA dissolved in a solvent under excess salt conditions, with a high concentration of sucrose in order to achieve a sufficiently high solvent viscosity, have been determined in the semidilute regime at room temperature. The dependence of the steady state uniaxial extensional viscosity on molecular weight, concentration and extension rate is measured with a view to determining if data collapse can be observed with an appropriate choice of variables. Steady state shear viscosity measurements suggest that sucrose-DNA interactions might play a role in determining the observed rheological behaviour of semidilute DNA solutions with sucrose as a component in the solvent., 30 pages, 9 figures, submitted to Korea-Australia Rheology Journal

This work discusses the first set of rheometric measurements carried out on commercially accessible juvenile and aged skin models under large amplitude oscillatory shear deformations. The results were compared with those of native male whole human and dermis-only foreskin specimens, catering to a few ages from 0.5 to 68 years, including specimens from a 23-year-old male abdomen. At large strains, strain thinning was more pronounced for the dermis of the young skins and for their whole skin counterparts. An inverse qualitative tendency was observed for the adult skins and the skin models. This can be explained by the high dermal collagen compactness associated with an incomplete epidermal proliferation. The qualitative Lissajous plots as well as the quantitative dimensionless indices analyzed using the MITlaos software indicated predominant nonlinear intracycle elastic strain stiffening and viscous shear thinning for all the native specimens at the maximum deformation. For the full thickness models, we have evidence of structure collapse and yielding under similar conditions. The whole skin specimen from the 68-year-old male showed smaller age-dependent nonlinear elastic contributions than the dermis, which we relate to the epidermal degeneration taking place during aging. Regardless of the age group, the models manifested more pronounced intercycle and intracycle elastic nonlinearities, and their magnitudes were significantly larger. The nonlinear elastic trends will serve as advanced standards for understanding and delineating the mechanical limits of destructive and non-destructive deformations of such unique biomaterials.

The study reports first ever account of measurements of linear viscoelastic moduli under small amplitude oscillatory shear deformations, for commercially available juvenile and aged in vitro 3D reconstructed skin models. The results were compared with those of native male whole human and dermis-only foreskin samples, catering to a wide age group from 0.5 to 68 years, including samples from a 23-year-old male abdomen. In the strain sweep tests, the dermis of the juvenile/young age group assumed a higher intrinsic elastic modulus than the whole skin. A reverse qualitative trend was noted for the adult/aged age group. Confirmed by the histological examination of the stained cross-sections, this is attributed to the nascent epidermal differentiation and the high fiber density of dermal collagen. The oscillation frequency sweeps exposed a greater dependence of the elasticity on the frequency for the native male dermis foreskin samples as compared to the whole skins, irrespective of age. This is anticipated since the extremely structured epidermis confers higher resistance to the whole skins towards intracycle deformations compared to the dermis, thereby storing smaller elastic energy. The 3D skin models examined in this work exhibited a broader linear viscoelastic region, a larger viscoelasticity, and much higher dynamic moduli, compared to the native skin. The rheological trends are a significant addition to the literature and may be used as a reference for the design of next generation of scaffolds.

The suitability and efficacy of three-dimensional (3D) graphene, including its derivatives, have garnered widespread attention towards the development of novel, sustainable materials with ecological amenability. This is especially relevant towards its utilization as adsorbents of wastewater contaminants, such as heavy metals, dyes, and oil, which could be majorly attributed to its noteworthy physicochemical features, particularly elevated chemical and mechanical robustness, advanced permeability, as well as large specific surface area. In this review, we emphasize on the adsorptive elimination of oil particles from contaminated water. Specifically, we assess and collate recent literature on the conceptualization and designing stages of 3D graphene-based adsorbents (3DGBAs) towards oil adsorption, including their applications in either batch or continuous modes. In addition, we analytically evaluate the adsorption mechanism, including sorption sites, physical properties, surface chemistry of 3DGBA and interactions between the adsorbent and adsorbate involving the adsorptive removal of oil, as well as numerous effects of adsorption conditions on the adsorption performance, i.e. pH, temperature, initial concentration of oil contaminants and adsorbent dosage. Furthermore, we focus on the equilibrium isotherms and kinetic studies, in order to comprehend the oil elimination procedures. Lastly, we designate encouraging avenues and recommendations for a perpetual research thrust, and outline the associated future prospects and perspectives.

A readily distinguishable and indigenous member of the plant kingdom in the Indian subcontinent is the 'drumstick tree', i.e.

The fact that atmospheric CO2 concentrations continue to rise rapidly, in response to increased combustion of fossil fuels, has been widely documented, and remains a potent contributor to global climate change. In order to tackle anthropogenic, energy-related CO2 emissions from large point sources, the development of inexpensive adsorbents for the selective removal of CO2 from the flue gas stream of fossil-fired power plants have become a top priority. Indeed, a wide range of porous materials, including zeolites, metal oxides, porous organic polymers, mesoporous silicates, activated carbon, carbon fibers, ion-exchange resins, and metal organic frameworks, have been comprehensively studied over a wide range of temperatures and pressures. Amongst them, activated carbon (AC) has garnered maximum attention, because of its enormous surface area, hierarchical porosity, outstanding thermostability, intrinsic hydrophobicity, as well as low acid/base reactivity. However, most commercial ACs are manufactured from expensive and nonrenewable fossil fuel-based resources, thereby precluding their practical implementation, especially at industrial scales. In order to overcome this challenge, the conversion of abundantly available carbon-rich natural resources to sustainable, carbonaceous adsorbents, has emerged as an optimal solution in recent years. In particular, utilizing the waste biomass from agriculture, stock farming, and other human activities as a base feedstock to mass-produce AC, for selective carbon capture, can actively contribute to solid waste management with a potential revenue benefit option. In addition, it may facilitate the conservation of our limited natural resources. This chapter provides a critical and all-inclusive account of the contemporary advancement in the synthesis and application of biomass-derived ACs for separating CO2 from flue gases. It principally covers the perspectives of fabrication and optimization schemes applicable to different kinds of biomass. Furthermore, associated challenges are pointed out and tactical research strategies and improvements are proposed, with an eye on the foreseeable future.

Sustainable development goals involve proper utilization and management of natural resources. Looking at the current scenario of worldwide water scarcity, it is high time to address the issue related to wastewater with cost-effective and sustainable technologies. In the age of nanotechnology, most of the research directly or indirectly connects with nanosciences. Nanomaterials are widely accepted for their effective performance in wastewater treatment, either as adsorbents or enhancers joining with membranes, and other treatment processes of degradation and disinfection. The trend of nanoparticles is increasing as it can increase the efficiency of an overall process with added economic advantage, for example, a suitable adsorbate can reduce the size of the adsorption column thereby cutting down the cost associated with it. In this chapter, we will review the potential risk and safety concerns of nanoparticles that are widely used for the wastewater treatment-related applications. Safety in handling of nanoparticles is well documented; however, safety of usage of nanoparticles in water treatment and its implications that may have a significant effect on water quality will to be extensively reviewed here. The application of nanotechnology in water treatment must have sustainability in every aspect and must address potential risk and safety concerns. Furthermore, this consolidation of scattered literature on the risk and safety of nanoparticles will be useful for researchers working on nanoparticle-related applications in general and wastewater treatment in particular.

This chapter archives the state of the art concerning crucial drug delivery strategies aiding in cardiovascular therapies, including their benefits and associated challenges. The aspects which govern vascular transport and cardiovascular drug targeting have been reviewed, both from configuration and flow perspectives. In addition, the role of extracellular vesicles and exosomes, as well as the suitability of ultrasound and microbubble-mediated delivery, has been discussed. Current advancements made in the nanomedicine domain, with relevant applications pertaining to diverse categories, have been collated and discussed. A special focus has been laid on the applications of aptamers in cardiovascular drug targeting, particularly with respect to conjugation with specific coagulation factors and proteins. It also captures the potential and promises of the next generation of targeted strategies, with an eye on the foreseeable future.

Metal oxide nanoparticles constitute one of the most conjoint subsets of nanosized particles that are under extensive research, attributing to their outstanding abilities to be useful as a catalyst, and in electronics and biomedical application domains. These nanoparticles are fabricated via physical, chemical, and biological approaches, and their properties depend on the selection of the particular synthesis strategy. However, these manufacturing methods possess certain limitations, which hurdles their benefits in large-scale applications. Consequently, metal oxide nanoparticles are blended with biocompatible polymers, to form nanocomposites for maintaining the stability, without compromising their additional significant properties. Contextually, waterborne polyurethanes are developed and incorporated with a wide variety of metal oxide nanoparticles, to form potential polymer-based nanocomposites with high biocompatibility, as well as mechanical and thermal stability. These novel nanocomposites are currently under investigation to be beneficial as coating materials or formulations in biomedical and environmental applications. This chapter aims to illustrate various types of magnetic and non-magnetic waterborne polyurethane-metal oxide nanocomposites, including their characteristics and specific functionalities. Furthermore, the advantages of utilizing these novel nanocomposites in biomedical and environmental applications are discussed, with an eye on their limitations and future outlook.

We report a custom-made technique to synthesize process-convenient skin scaffolds by tuning the mechanical properties of hydrogels based on a few naturally occurring polysaccharides to match the rheological properties of previously established benchmarks, i.e., the ex vivo native human skins. We studied the mechanical parameters using oscillatory shear rheology. At small strain amplitudes, the intrinsic elastic modulus showed an almost linear dependence in the middle and a changing rate profile at the two ends with concentration of the principal hydrogel component variant, i.e., kappa (κ)-carrageenan. At large strain amplitudes, the hydrogels demonstrated intercycle strain-softening behavior, the onset of which was directly proportional to the κ-carrageenan concentration. We observed a concentration match for the intrinsic elastic modulus of the benchmark within this sigmoidal curve fit. Contextually, we need to explore other potent polymeric hydrogel systems to achieve mechanical affinity in terms of multiple rheological parameters derived from both strain amplitude and angular frequency sweeps. Additionally, we carried out diffusion experiments to study caffeine permeation attributes. The hydrogels show improved barrier features with increasing κ-carrageenan concentration. In terms of the penetration flux and total cumulative amount of permeated caffeine, this enhanced mechanical adherence demonstrates comparable penetration features with the commercial 3D skin model.

The integration of graphene or graphene oxide nanosheets into three‐dimensional (3D) graphene‐based macromolecular assemblies (GMAs), in the form of sponges, beads, fibres, films, and crumpled nanosheets, has greatly advanced their environmental remediation applications. This is attributed to the outstanding physicochemical characteristics and superlative mechanical features of 3D GMAs, including precise and physically linked permeable networks, enormous surface area, profound porosity, and high‐class sturdiness, amongst others. In this review, the recent advancements towards the exploration of 3D GMAs as an exciting new class of high‐performance adsorbents, for eliminating toxic heavy metal ions from both wastewater and freshwater, are systematically summarized and discussed, from both fundamental and applied perspectives. In particular, the numerous surface modification techniques that are actively pursued to enrich the metal adsorption capacity of 3D GMAs, are comprehensively examined. Additionally, associated challenges are pointed out and tactical research strategies and improvements are proposed, with an eye on the conceivable future., Self‐assembly of graphene and graphene oxide nanosheets into 3D macrostructures is a powerful strategy to create multifunctional materials for sustainable environmental applications. In this Minireview, recent advances in the development of exotic graphene‐based macromolecular assemblies for heavy metal scavenging, are critically examined.

Vesicle structures primarily embody spherical capsules composed of a single or multiple bilayers, entrapping a pool of aqueous solution in their interior. The bilayers can be synthesised by phospholipids or other amphiphiles (surfactants, block copolymers, etc.). Vesicles with broad-spectrum applications in numerous scientific disciplines, including biochemistry, biophysics, biology, and various pharmaceutical industries, have attracted widespread attention. Consequently, a multitude of protocols have been devised and proposed for their fabrication. In this review, with a motivation to derive the basic conditions for the formation of vesicles, the associated thermodynamic and kinetic aspects are comprehensively appraised. Contextually, an all-purpose overview of the underlying thermodynamics of bilayer/membrane generation and deformation, including the chemical potential of aggregates, geometric packing and the concept of elastic properties, is presented. Additionally, the current review highlights the probable, inherent mechanisms of vesicle formation under distinct modes of manufacturing. We lay focus on vesicle formation from pre-existing bilayers, as well as from bilayers, which form when lipids from an organic solvent are transferred into an aqueous medium. Furthermore, we outline the kinetic effects on vesicle formation from the lamellar phase, with and without the presence of shearing force. Wherever required, the experimental and/or theoretical outcomes, the driving forces for vesicle size selection, and various scaling laws are also reviewed, all of which facilitate an overall improved understanding of the vesicle formation mechanisms.

Microalgae are underutilized organisms with multifaceted bio-relevance beyond their potential as sources of sustainable biofuels. Microalgae are unique sources of bioactive compounds and proteins with nutritional, functional, and health benefits. Although the use of microalgae as food and feed dates back several centuries, strategic scientific evaluations of the nutritional value and health benefits have increasingly garnered attention in recent times, especially as sustainable, alternative sources of dietary protein. Major criteria in evaluating the nutritional value of novel food and feed sources are the protein content, amino acid profile, digestibility, protein utilization, and the protein needs of consumers. The nutritional value of microalgae is affected by biotic and abiotic factors and genomic variation between species. Using endogenous and exogenous proteases, microalgal proteins can be hydrolyzed to generate bioactive peptides with potential physiological effects in the human body, such as opioid-like, antithrombotic, immunomodulatory, and antihypertensive activities. One major challenge faced when using whole microalgae as a dietary protein source is poor digestibility, which is mostly due to the rigid and recalcitrant nature of many microalgal cell walls. This challenge can be circumvented with chemical, mechanical, and enzymatic pretreatments of microalgal biomass prior to protein extraction or food/feed product development. This chapter discusses the nutritional value and health benefits of microalgae proteins and peptides as well as the current challenges and future direction in protein assessment methods.

Essential oils, secreted by plants, are primarily meant for various physiological, ecological, and defense activities. These oils belong to various classes, i.e., isolates of fatty acids, isoprenoids, and phenolic complexes, and can be secreted by various organs of plants. The essential oil market globally has been predicted to grow at a compound annual growth rate (CAGR) of ~8–10%, and reach a staggering figure in excess of USD ten billion in the next 5 years or so. However, the challenge lies in commercial production, keeping pace with the demand, since their natural production in plants is in considerably low quantities, which depends on ecological conditions and growth stages of the plant. Although several investigations exist in the literature, there is a pressing need for a systematic review of the recent updates, particularly concerning the strategies that facilitate the manufacturing of such indispensable oils. The current chapter focuses on various facets of essential oil production, the associated challenges, and the promise of genetic alteration techniques for enhanced essential oil production. Several distinct perspectives have been considered, such as different sources and mechanisms of essential oil biomanufacturing, including their role in plant defense, the array of isolation procedures, and their wide ranges of beneficial attributes, particularly catering to the therapeutic potential, and challenges and metabolic engineering characteristics. A crucial feature of the current chapter is a critical review, underlining these aspects with a case study, using the commercially valuable sandalwood oil as an example, to emphasize the genetic modification strategies for enhancing sandalwood oil.

The depletion of petroleum and fossil fuels and the escalating problem of climate change motivate and compel an ongoing effort focusing on the development of renewable energy in the form of biofuels. Biobutanol is one such potent biofuel, attributing to similar characteristics as of gasoline, which manifests in easier public distribution based on the current oil and gas infrastructure. Also, the development of the third-generation biofuels sourced from cultivation of microalgae seems an outright promising prospect for renewable energy sources. This is mainly because of its inherent advantages in comparison to the previous methods of biofuel production from crops and plant waste. However, in spite of the ongoing efforts, the research targeting towards biobutanol production utilizing microalgal resources is insufficient. Working on the strengths of both may provide the much needed boost for the thriving biofuel industry, ultimately aiding to cope with global energy demand and reduce CO2 emissions. In this review, the design and selection of a complete industrial scale biobutanol production plant, using microalgae as the feedstock, have been proposed. Advances in bioprocess technologies for biobutanol production via fermentation and biobutanol recovery methods are described. In addition, comparative analyses of biobutanol versus petroleum diesel and biodiesel, and strategies for biobutanol cum lipid and methane gas manufacturing are also discussed.

The nonlinear rheological behaviors of concentrated double-stranded (ds) and single-stranded (ss) DNA solutions were studied under standard oscillatory and large amplitude oscillatory shear (LAOS) deformations. To decompose the total stress into the elastic and viscous components, the raw nonlinear waveforms were analyzed using the MITlaos software package. We found that smooth and rigorous intracycle strain stiffening and shear thinning dominate the elastic and viscous decomposition, respectively, of the ds DNA sample. In contrast, the ss DNA sample exhibits initial intracycle strain stiffening, followed by a transition region and a terminal flow behavior. Insights into the nonlinear response of the DNA solutions were achieved by performing particle image velocimetry (PIV) at a wide range of imposed strain amplitudes and two angular frequencies. The rheo-PIV results of the ds DNA sample show a substantially modified flow field with distinct strain-driven shear bands at both angular frequencies examined. The bands formed by the ss DNA sample were weak even at the maximum strain amplitude. The results from this work are insightful from a traditional bulk rheological perspective, as well as for further single-molecular studies.

The response of semidilute entangled and salt-free solutions of aqueous polyacrylamide under large amplitude oscillatory shear deformations was studied in this work. We systemically probed the effects of four polymer concentrations from 5 to 15 wt. % and two molecular weights (5–6 and 18 M) at De > 1. The mitlaos software package was utilized to analyze the nonlinear moduli, among other nonlinear parameters. We found that the polymer concentration is the dominant parameter controlling the progression into the nonlinear regime. The trends of elastic decomposition indicate an intensive strain-rate softening behavior under high strain amplitudes. At high strain rates and at higher concentrations, however, a gradual transition from shear thickening to shear thinning could be noticed for the viscous dissipation. In addition, the effect of the measuring geometry was also considered, since the rheometer was coupled with a particle image velocimetry (PIV) system in the second part of this study. The PIV results s...

The food and health applications of bioactive peptides have grown remarkably in the past few decades. Current elucidations have shown that bioactive peptides have unique structural arrangement of amino acids, conferring distinct functionalities, and molecular affinity characteristics. However, whereas interest in the biological potency of bioactive peptides has grown, cost-effective techniques for monitoring the structural changes in these peptides and how these changes affect the biological properties have not grown at the same rate. Due to the high binding affinity of aptamers for other biomolecules, they have a huge potential for use in tracking the structural, conformational, and compositional changes in bioactive peptides. This review provides an overview of bioactive peptides and their essential structure-activity relationship. The review further highlights on the types and methods of synthesis of aptamers before the discussion of the prospects, merits, and challenges in the use of aptamers for bioaffinity interactions with bioactive peptides.

The emerging beneficial characteristics of bio-active peptides have made them suitable candidates for a wide range of applications. While their usage as potent nutraceutical and pharmaceutical agents has been well-documented, applications of bio-active peptides in addressing sustainable agricultural challenges relating to biotic and abiotic stresses, plant disease control, and nutrient use efficiency have not received much attention. Bio-active peptides are specific fragments of proteins with amino acid structures capable of enhancing molecular signaling in the rhizosphere to promote nodulation, nutrient uptake, and stress management. Bio-active peptides can be formulated with agrochemicals and assimilated through the leaf system in foliar treatments to achieve a wide range of plant benefits including coloring, nutrient delivery under drought conditions, plant health, and crop protection. Harnessing the maximum potential of bio-active peptides in sustainable agriculture is a rational contemplation, since the current years have witnessed a radical upsurge in the manufacturing scale of bio-active peptides under optimum economy. The present chapter discusses the unique potential of bio-active peptides in promoting sustainable agriculture. Moreover, the molecular mechanisms of bio-active peptides in influencing plant stress relief, disease control, and nutrient assimilation efficiency and signaling routes are also elaborated. Additionally, a few advanced standpoints pertaining to optimal utilization of bio-active peptides in advancing agricultural productivity are also discussed.

Algae possess inherent complex physiological photosynthetic mechanisms, which enable beneficial transformation of solar energy into other energy forms, for food and active metabolite synthesis. A number of active metabolites derived from algae, many of which demonstrate bioactive properties, have found profound, multifunctional applications in biofuels, nutraceuticals and functional foods, pharmaceuticals, and cosmetics industries. In spite of the evolving global interests and market demand of algal biomass and metabolites, studies and applications pertaining to sustainable agriculture challenges, such as soil nutrient deficiency, drought stress, soil toxicity, leaf discoloration and plant growth stunts, are limited. The generation and functional determination of novel bioactive compounds from algal biomass may offer innovative opportunities to address some of the aforementioned challenges. This chapter profiles and discusses the prospects of key algal metabolites in addressing plant growth challenges. Additionally, research findings from specific studies based on the use of algal metabolites and phytohormones as biostimulants, their influence in host animal physiology, and protective mechanisms against adventitious organisms or foreign pathogens, have been discussed. The chapter lays down progressive perspectives for optimal exploitation of algal metabolites and phytohormones in enhancing agricultural outputs.

Endophytes are the microorganisms present within the living tissues of plants. It has been suggested that every plant harbours at least one to two endophytes. However, very few plants have been characterized for their endophytic population, in comparison to their known diversity. A search in PubMed using the keyword ‘endophyte’ shows that there has been a considerable increase in the number of publications focusing on endophytes, i.e., 32 in the 2000s to ~500 in 2017 and roughly 200 in the first few months of 2018. The trend suggests increasing interest in endophytes as sources of novel metabolites. The pointers in early studies had shown the presence of novel natural compounds produced by endophytes. Indeed, the therapeutic molecules in many plants have been proposed to be produced by endophytes and not the host plants themselves. These molecules have the potential to serve as added resources in the desperate search for bio-active compounds which can combat various diseases and syndromes prevalent today and which are fast-losing effective therapeutics. Their presence in plants growing in diverse habitats adds to their potential for chemo-diversity. Modern omics technologies, involving next-generation sequencing, metagenomics and metatranscriptomics, have shown a promise in better understanding of plant-endophyte relationships and can play a significant role in establishing the biosynthetic potential of endophytes. Therefore, bioprospecting for endophytes constitutes an attractive area of research. Thus, the current chapter provides a comprehensive account of these microorganisms as they correlate to various habitats, their role in ‘benefit-sharing’ with their hosts and the recent technologies which have unveiled their involvement in various aspects of their host plants’ lives.

Dyes are an important class of recalcitrant organic compounds, with a broad range of applications in the textiles and clothing industry. It is estimated that almost 2% of the dyes produced annually are discharged directly onto aqueous effluents through manufacturing and processing operations, and nearly 10% is subsequently lost during the coloration process. The presence of dyes in industrial wastewaters can create a host of environmental problems because of their potential cytotoxic, carcinogenic, and mutagenic effects on human health, as well as on general flora and fauna. Amongst the various physical, chemical, and biological techniques that are currently explored by the scientific community for the removal of dyes from aqueous medium, adsorption on activated carbon (AC) is widely considered as the most effective and promising option. However, commercially available ACs are fairly expensive and are often produced from non-renewable coal based resources, which make them economically undesirable and environmentally unsustainable. Consequently, there is a growing interest to synthesize ACs from renewable agricultural waste, which is conceived to be sufficiently abundant. Particularly, attributing to their high lignocellulosic composition and low ash content, date palm residues (such as fibers, seeds, rachis, fronds, etc.) as low cost precursors for manufacturing ACs are being intensively investigated in recent years. Compared to the commercial AC, the ACs derived from date palm byproducts exhibit superior textural characteristics, and, subsequently, greater adsorption capacity toward a plethora of dyes. Clearly, solicitations of date palm biomass, as a base feedstock for the mass production of AC, can not only solve the waste disposal crisis in date palm growing countries, with a beneficial and enhanced revenue potential, but may also contribute in regulation of the unsustainable management of the waste byproduct. This chapter targets this aspect amongst others, with an objective to provide a systematic overview of the recent progress in the development and application of date palm based ACs for decolorizing textile effluents. Furthermore, it attempts to segregate and identify the key gaps in the specific domain knowledge, and lays out novel strategic research guidelines, for making further advances in this promising approach, to a hitherto sustainable development.

Magnesium Oxide (MgO) nanoparticles are known to play a significant role in lowering the production of lipids and serum glucose for diabetes treatment. Additionally, the emergence of aptamers has created new opportunities in the realization of smart drug delivery systems, mainly attributing to their abilities to be altered at the molecular level, and subsequently be conjugated onto biopolymers harbouring specific drugs, in order to navigate specific cellular sites. The current work reports the synthesis of a multifunctional aptamer-navigated particulate delivery system (DPAP), harbouring MgO (synthesized via chemical - MgO1 and green – MgO2 approaches) nanoparticles, to target 3T3-L1 diabetic cells. In vitro performance indicators, including encapsulation efficiency, targeting capability, cellular transfection efficiency, and insulin reversal capacity, were investigated. While the DLS analysis indicated hydrodynamic sizes of 766.6 nm and 641.3 nm for the DPAP-MgO1 and DPAP-MgO2 formulations, respectively; and zeta potentials of +5.28 mV and −0.025 mV, for the same formulations, respectively. Additionally, DPAP-MgO2 offered better encapsulation efficiency and loading capacity of 93.69% and 0.03 mg MgO/mg PLGA, respectively. 3,5-Dinitrosalicylic acid (DNS) assessment showed that both DPAP-MgO1 and DPAP-MgO2 particulate systems enhanced the in vitro cellular uptake, as well as the insulin resistance reversal ability of the 3T3-L1 cells. The outcomes from the current work demonstrate the potential of DPAP particulate system as an effective and promising carrier, for the delivery of MgO nanoparticles in diabetes treatment.

Immobilisation of aptameric ligands on solid stationary supports for effective binding of target molecules requires understanding of the relationship between aptamer-polymer interactions and the conditions governing the mass transfer of the binding process. Herein, key process parameters affecting the molecular anchoring of a thrombin-binding aptamer (TBA) onto polymethacrylate monolith pore surface, and the binding characteristics of the resulting macroporous aptasensor were investigated. Molecular dynamics (MD) simulations of the TBA-thrombin binding indicated enhanced Guanine 4 (G4) structural stability of TBA upon interaction with thrombin in an ionic environment. Fourier-transform infrared spectroscopy and thermogravimetric analyses were used to characterise the available functional groups and thermo-molecular stability of the immobilised polymer generated with Schiff-base activation and immobilisation scheme. The initial degradation temperature of the polymethacrylate stationary support increased with each step of the Schiff-base process: poly(Ethylene glycol Dimethacrylate-co-Glycidyl methacrylate) or poly(EDMA-co-GMA) [196.0 °C (±1.8)]; poly(EDMA-co-GMA)-Ethylenediamine [235.9 °C (±6.1)]; poly(EDMA-co-GMA)-Ethylenediamine-Glutaraldehyde [255.4 °C (±2.7)]; and aptamer-modified monolith [273.7 °C (±2.5)]. These initial temperature increments reflected in the associated endothermic energies were determined with differential scanning calorimetry. The aptameric ligand density obtained after immobilisation was 480 pmol/μL. Increase in pH and ionic concentration affected the surface charge distribution and the binding characteristics of the aptamer-modified disk-monoliths, resulting in the optimum binding pH and ionic concentration of 8.0 and 5 mM Mg2+, respectively. These results are critical in understanding and setting parametric constraints indispensable to develop and enhance the performance of aptasensors.