Remediation of Dyes Using Supramolecular Material Derived from Carbohydrate Based π-Gelator Using the Bottom-Up Assembly Approach.

As a consequence of rapid population growth, the earth has faced numerous environmental sustainability issues and crises, water pollution is one of the important points of concern because of industrialization. In particular, effluents discharged from dying industries are rated top among the various industrial effluents, especially by their volume and composition. Annually >7.5 × 105 metric tons of different dyes are produced and consumed in different industries. In order to dye 1 kg of fabric, approximately 100-150 L of water is required, and after the dying process, it is discharged as an effluent either on a landfill or in water bodies. It is our responsibility to conserve environmental sustainability. In this line, we have developed a simple protocol to generate carbohydrate-based amphiphile using D-sorbitol, and pyrene-1-carboxaldehyde in good yield. This carbohydrate-based π-gelator is prone to forming a gel in various solvents and oils by the bottom-up assembly process. Morphological analysis of the self-assembled structure was identified by using optical microscopy and SEM. The viscoelastic behavior of the gel was examined by using rheology. In this paper, we explored the dye adsorption and desorption characteristics of the gel. Further, we have developed a cartridge based on cellulose using a template-assisted assembly phenomenon and demonstrated its potential in adsorbing dyes such as methylene blue, crystal violet, rhodamine B, and Congo red.

Self-Assembling Nanoarchitectonics of Twisted Nanofibers of Fluorescent Amphiphiles as Chemo-Resistive Sensor for Methanol Detection.

The inhalation, ingestion, and body absorption of noxious gases lead to severe tissue damage, ophthalmological issues, and neurodegenerative disorders; death may even occur when recognized too late. In particular, methanol gas present in traces can cause blindness, non-reversible organ failure, and even death. Even though ample materials are available for the detection of methanol in other alcoholic analogs at ppm level, their scope is very limited because of the use of either toxic or expensive raw materials or tedious fabrication procedures. In this paper, we report on a simple synthesis of fluorescent amphiphiles achieved using a starting material derived from renewable resources, this material being methyl ricinoleate in good yields. The newly synthesized bio-based amphiphiles were prone to form a gel in a broad range of solvents. The morphology of the gel and the molecular-level interaction involved in the self-assembly process were thoroughly investigated. Rheological studies were carried out to probe the stability, thermal processability, and thixotropic behavior. In order to evaluate the potential application of the self-assembled gel in the field of sensors, we performed sensor measurements. Interestingly, the twisted fibers derived from the molecular assembly could be able to display a stable and selective response towards methanol. We believe that the bottom-up assembled system holds great promise in the environmental, healthcare, medicine, and biological fields.

Hybrid hydrogels derived from renewable resources as a smart stimuli responsive soft material for drug delivery applications.

The design and synthesis of amphiphilic molecules play a crucial role in fabricating smart functional materials via self-assembly. Especially, biologically significant natural molecules and their structural analogues have inspired chemists and made a major contribution to the development of advanced smart materials. In this report, a series of amphiphilic N-acyl amides were synthesized from natural precursors using a simple synthetic protocol. Interestingly, the self-assembly of amphiphiles 6a and 7a furnished a hydrogel and oleogel in vegetable oils. Morphological analysis of gels revealed the existence of a 3-dimensional fibrous network. Thermoresponsive and thixotropic behavior of these gels were evaluated using rheological analysis. A composite gel prepared by the encapsulation of curcumin in the hydrogel formed from 7a displayed a gel-sol transition in response to pH and could act as a dual channel responsive drug carrier.

Glycolipid-Based Oleogels and Organogels: Promising Nanostructured Structuring Agents.

Over the past few decades, the scientific community is actively involved in the development of edible structuring agents suitable for food, cosmetics, agricultural, pharmaceutical, and biotechnology applications. In particular, edible oil structuring using simple amphiphiles would be the best alternative for the currently used trans and saturated fatty acids, which cause deleterious health effects and cardiovascular problems. In this report, we have made an attempt to address the aforementioned consequences, by synthesizing a new class of structuring agents by a judicious combination of δ-gluconolactone and ricinoleic acid, compounds classified as GRAS, using simple steps in good yield. To our delight, the synthesized glycolipids self-assemble in a wide variety of vegetable oils and commercially viable glycerol, ethylene glycol, and polyethylene glycol via various intermolecular interactions to form a gel. The morphology of molecular gels was investigated by optical microscopy and FESEM analysis, which reveal the existence of a tubular architecture with a diameter ranging from 75 to 150 nm. Rheological studies disclosed the viscoelastic nature, thermal processability, and thixotropic behavior of both oleogels and organogels. Altogether, self-assembled oleogel and organogel reported in this paper would potentially be used in food, agricultural, cosmetics, pharmaceutical, and biotechnological applications.

An injectable self-healing anesthetic glycolipid-based oleogel with antibiofilm and diabetic wound skin repair properties.

Globally, wound infections are considered as one of the major healthcare problems owing to the delayed healing process in diabetic patients and microbial contamination. Thus, the development of advanced materials for wound skin repair is of great research interest. Even though several biomaterials were identified as wound healing agents, gel-based scaffolds derived from either polymer or small molecules have displayed promising wound closure mechanism. Herein, for the first time, we report an injectable and self-healing self-assembled anesthetic oleogel derived from glycolipid, which exhibits antibiofilm and wound closure performance in diabetic rat. Glycolipid derived by the reaction of hydrophobic vinyl ester with α-chloralose in the presence of novozyme 435 undergoes spontaneous self-assembly in paraffin oil furnished an oleogel displaying self-healing behavior. In addition, we have prepared composite gel by encapsulating curcumin in the 3D fibrous network of oleogel. More interestingly, glycolipid in its native form demoed potential in disassembling methicillin-resistant Staphylococcus aureus, methicillin-susceptible Staphylococcus aureus, and Pseudomonas aeruginosa biofilms. Both oleogel and composite gel enhanced the wound skin repair in diabetic induced Wistar rats by promoting collagen synthesis, controlling free radical generation and further regulating tissue remodeling phases. Altogether, the reported supramolecular self-assembled anesthetic glycolipid could be potentially used for diabetic skin wound repair and to treat bacterial biofilm related infections.

Fabrication of Biobased Hydrophobic Hybrid Cotton Fabrics Using Molecular Self-Assembly: Applications in the Development of Gas Sensor Fabrics.

Inadvertent inhalation of various volatile organic compounds during industrial processes, such as coal and metal mining, metal manufacturing, paper and pulp industry, food processing, petroleum refining, and concrete and chemical industries, has caused an adverse effect on human health. In particular, exposure to trimethylamine (TMA), a fishy odor poisonous gas, resulted in numerous health hazards such as neurotoxicity, irritation in eyes, nose, skin, and throat, blurred vision, and many more. According to the environmental protection agency, TMA in the level of 0.10 ppm is generally considered as safe, and excess dose results in "trimethylaminuria" or "fish odor syndrome." In order to avoid the health hazards associated with the inhalation of TMA, there is an urge to design a sensor for TMA detection even at low levels for use in food-processing industries, medical diagnosis, and environment. In this report, for the first time, we have developed a TMA sensor fabric using a sequential self-assembly process from silver-incorporated glycolipids. Formation of self-assembled supramolecular architecture, interaction of the assembled structure with the cotton fabric, and sensing mechanism were completely investigated with the help of various instrumental methods. To our surprise, the developed fabric displayed a transient response for 1-500 ppm of TMA and a stable response toward 100 ppm of TMA for 15 days. We believe that the reported flexible TMA sensor fabrics developed via the sequential self-assembly process hold great promise for various innovative applications in environment, healthcare, medicine, and biology.

Smart supramolecular gels of enolizable amphiphilic glycosylfuran.

The implementation of a novel approach in the development of stimuli responsive supramolecular gels is an important objective that challenges material chemists and biologists in order to access an exclusively new category of smart materials. In this report, non-toxic, bio-based amphiphilic glycosylfurans were designed and synthesized using a biocatalyst, Novozyme 435, an immobilized lipase B from Candida antarctica. The self-assembly of these compounds generated oleogels and hydrogels. To our delight, these bio-based amphiphilic glycosylfurans furnished an in situ stimuli responsive hydrogel with simultaneous encapsulation of various biologically relevant molecules and ions. For the first time we are reporting hydrogelation via in situ molecular tuning followed by a self-sorting mechanism. The sol-to-gel transition in the reported smart hydrogel was observed by the addition of acidic buffer of pH 4.0, which could be potentially used for the stimuli responsive delivery of a signalling molecule, H2S and other biomolecules that regulate many physiological and pathological processes.

Lipase-Catalyzed Synthesis of Furan-Based Oligoesters and their Self-Assembly-Assisted Polymerization.

We investigate the synthesis of bio-based hydrophilic and hydrophobic oligoesters, which in turn are derived from easily accessible monomers from natural resources. In addition to the selection of renewable monomers, Novozyme 435, an immobilized lipase B from Candida antarctica was used for the oligomerization of monomers. The reaction conditions for oligomerization using Novozyme 435 were established to obtain a moderate-to-good yield. The average number of repeating units and the molecular weight distribution of hydrophilic and hydrophobic oligoester were identified by using NMR spectroscopy, gel-permeation chromatography, and MS. The oligoester derived from a hydrophilic monomer self-assembled to form a viscous solution, which upon further heating resulted in the formation of a polymer by the intermolecular Diels-Alder reaction. The viscosity of the solution and the assembly of oligoester to form a fibrous structure were investigated by using rheological studies, XRD, and SEM. The molecular weight of the cross-linked polymer was identified by using matrix-assisted laser desorption/ionization-MS. The thermal properties of the bio-based polymers were investigated by using thermogravimetric analysis and differential scanning calorimetry. For the first time, the self-assembly-assisted polymerization of an oligoester is reported using the intermolecular Diels-Alder reaction, which opens a new avenue in the field of polymer science.

Enzymatic synthesis and self-assembly of glycolipids: robust self-healing and wound closure performance of assembled soft materials.

In developing countries, wounds are a major health concern and pose a significant problem. Hence, the development of new materials that can act as scaffolds for in situ tissue regeneration and regrowth is necessary. In this report, we present a new class of injectable oleogel and composite gel derived from glycolipids that provide reversible interlinked 3D fiberous network architecture for effective wound closure by tissue regrowth and regeneration. Glycolipids were derived from α-chloralose and various vinyl esters using Novozyme 435, an immobilized lipase B from Candida antarctica as a catalyst, in good yield. These glycolipids undergo spontaneous self-assembly in paraffin oil to form an oleogel, in which curcumin was successfully incorporated to generate a composite gel. Morphological analysis of the oleogel and composite gel clearly revealed the formation of a 3D fiberous network. Rheological investigation revealed the thermal and mechanical processability of the oleogel and composite gel under various experimental conditions. Interestingly, the developed injectable oleogel and composite gel are able to accelerate the wound healing process by regulating the overlapping phases of inflammation, cell proliferation and extracellular matrix remodelling. Since chloralose displays anesthetic properties, this study will establish a new strategy to develop anesthetic wound healing oleogels in the future.

Disassembly of Bacterial Biofilms by the Self-Assembled Glycolipids Derived from Renewable Resources.

More than 80% of chronic infections of bacteria are caused by biofilms. It is also a long-term survival strategy of the pathogens in a nonhost environment. Several amphiphilic molecules have been used in the past to potentially disrupt biofilms; however, the involvement of multistep synthesis, complicated purification and poor yield still remains a major problem. Herein, we report a facile synthesis of glycolipid based surfactant from renewable feedstocks in good yield. The nature of carbohydrate unit present in glycolipid influence the ring chain tautomerism, which resulted in the existence of either cyclic structure or both cyclic and acyclic structures. Interestingly, these glycolipids self-assemble into gel in highly hydrophobic solvents and vegetable oils, and displayed foam formation in water. The potential application of these self-assembled glycolipids to disrupt preformed biofilm was examined against various pathogens. It was observed that glycolipid 6a disrupts Staphylococcus aureus and Listeria monocytogenes biofilm, while the compound 6c was effective in disassembling uropathogenic E. coli and Salmonella enterica Typhimurium biofilms. Altogether, the supramolecular self-assembled materials, either as gel or as surfactant solution could be potentially used for surface cleansing in hospital environments or the food processing industries to effectively reduce pathogenic biofilms.

Morphology transition in helical tubules of a supramolecular gel driven by metal ions.

Our aim to access a particular chemical functionality on helical tubules has been achieved by the rational molecular design and synthesis of glucono-appended cardanol derivatives. For the first time, we report a chiral molecular packing with α-helical tubules, and chiral symmetry-breaking upon exposure to Cu2+ that generated the final ordered structure via an in situ morphological transition without undergoing any phase change.

Supramolecular Gel Formation Based on Glycolipids Derived from Renewable Resources.

The potential applications of self-assembled supramolecular gels based on natural molecules encouraged the researchers to develop a versatile synthetic method for their structural analogues. Herein, we report a facile synthesis of glycolipid from renewable resources, cashew nut shell liquid,d and d-glucose in good yield. Gelation behavior of these glycolipids were studied in a wide range of solvents and oils. To our delight, compound 5b formed a hydrogel with Critical gelator concentration (CGC) of 0.29% w/v. Morphological analysis of the hydrogel depicts the formation of twisted fibers with an entangled network. Formation of a twisted fibrous structure was further identified by CD spectral studies with respect to temperature. The molecular self-assembly assisted by hydrogen bonding, hydrophobic, and π⁻π stacking interactions were identified by X-ray diffraction (XRD) and FTIR studies. Rheological analysis depicted the mechanical strength and stability of the hydrogel, which is crucial in predicting the practical applications of supramolecular soft materials.

Stimuli responsive hydrogels derived from a renewable resource: synthesis, self-assembly in water and application in drug delivery.

We designed and synthesised coumarin-tris derivatives from a renewable resource and well characterized them using different spectral techniques. The self-assembly of coumarin-tris amphiphiles into hydrogels was examined relative to the molecular structure of the amphiphiles. The reversible morphological transition from nanofibers to vesicles and nanotubes has been observed, upon pH variation. Reversible processes and self-assembled structures such as gel, vesicle and nanotube formation have been investigated using optical microscopy and high resolution transmission electron microscopy (HRTEM). 1H NMR and XRD studies clearly suggest that the π-π stacking interactions and hydrogen bonding were the driving force for the process of gelation. The flow behaviour of the hydrogel has been identified using rheological measurements. More importantly, the chemopreventive drug curcumin has been encapsulated into the gel and subsequent release has been achieved by a gel-to-sol transition induced by pH and Fe3+ metal ion stimuli. The reported hydrogel could play a substantial role in the development of new generation stimuli responsive drug delivery systems for in vivo formulations.

Strongly fluorescent organogels and self-assembled nanostructures from pyrene coupled coumarin derivatives: application in cell imaging.

Three different coumarin coupled pyrene derivatives with varying hydrophobic units (alkyl chains) have been synthesised and well characterized using NMR and mass spectral analysis. The gelation behaviour and self-aggregation properties of these compounds were studied relative to the molecular structure and solvent affinity. Among these derivatives, the one which is not having any hydrophobic tail displays efficient gelation in higher alcohols such as decanol and dodecanol. However the other derivatives having saturated and unsaturated hydrophobic tails form weak gel in different solvents. The morphology of gel was investigated by optical microscopy and high resolution transmission electron microscopy (HRTEM). The investigation of absorption and emission spectra of these compounds revealed that the photo-physical properties were significantly influenced by the self-assembly process in different solvents. The concentration dependent emission and 1H NMR studies clearly suggest that the π-π stacking interaction and hydrogen bonding between carbonyl groups of coumarin coupled pyrene with the -OH group of solvent were the driving forces for the process of gelation and self-aggregation. Rheological investigation clearly demonstrates the flow behaviour and reversible nature of organogel under temperature and strain ramp up and ramp down experimental conditions. By getting clue from the self-assembly mechanism in different solvents, we derived nano-flakes from coumarin coupled pyrene derivatives and further explored their potential applications in the field of cell imaging. The size of the self-aggregated particles in the DMSO-water mixture has been identified using HRTEM and a zetasizer. The nanomaterials obtained via the self-assembly process were used for fibroblast and PC3 prostate cancer cell imaging applications. Further investigation reveals that these compounds suppress the proliferation of PC3 cells.

Recent developments in ß-C-glycosides: synthesis and applications.

In the last few years, considerable progress has been made in the synthesis of C-glycosides. Despite its challenging chemistry, due to its versatility, C-glycosides play a pivotal role in developing novel materials, surfactants and bioactive molecules. In this review, we present snapshots of various synthetic methodologies developed for C-glycosides in the recent years and the potential application of C-glycosides derived from ß-C-glycosidic ketones.