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.

Many bacteria secrete a highly hydrated framework of extracellular polymer matrix on suitable substrates and embed within the matrix to form a biofilm. Bacterial biofilms are observed on many medical devices, endocarditis, periodontitis and lung infections in cystic fibrosis patients. Bacteria in biofilm are protected from antibiotics and >1,000 times of the minimum inhibitory concentration may be required to treat biofilm infections. Here, we demonstrated that shock waves could be used to remove Salmonella, Pseudomonas and Staphylococcus biofilms in urinary catheters. The studies were extended to a Pseudomonas chronic pneumonia lung infection and Staphylococcus skin suture infection model in mice. The biofilm infections in mice, treated with shock waves became susceptible to antibiotics, unlike untreated biofilms. Mice exposed to shock waves responded to ciprofloxacin treatment, while ciprofloxacin alone was ineffective in treating the infection. These results demonstrate for the first time that, shock waves, combined with antibiotic treatment can be used to treat biofilm infection on medical devices as well as in situ infections.

Bacterial biofilms display a collective lifestyle, wherein the cells secrete extracellular polymeric substances (EPS) that helps in adhesion, aggregation, stability, and to protect the bacteria from antimicrobials. We asked whether the EPS could act as a public good for the biofilm and observed that infiltration of cells that do not produce matrix components weakened the biofilm of Salmonella enterica serovar Typhimurium. EPS production was costly for the producing cells, as indicated by a significant reduction in the fitness of wild type (WT) cells during competitive planktonic growth relative to the non-producers. Infiltration frequency of non-producers in the biofilm showed a concomitant decrease in overall productivity. It was apparent in the confocal images that the non-producing cells benefit from the EPS produced by the Wild Type (WT) to stay in the biofilm. The biofilm containing non-producing cells were more significantly susceptible to sodium hypochlorite and ciprofloxacin treatment than the WT biofilm. Biofilm infiltrated with non-producers delayed the pathogenesis, as tested in a murine model. The cell types were spatially assorted, with non-producers being edged out in the biofilm. However, cellulose was found to act as a barrier to keep the non-producers away from the WT microcolony. Our results show that the infiltration of non-cooperating cell types can substantially weaken the biofilm making it vulnerable to antibacterials and delay their pathogenesis. Cellulose, a component of EPS, was shown to play a pivotal role of acting as the main public good, and to edge-out the non-producers away from the cooperating microcolony.

Carbohydrates are versatile materials widely used for several applications including food, pharmaceuticals, cosmetics, and drug delivery systems due to their inherent properties such as non-toxicity, biodegradability, and bio-compatibility. Specifically, the urge on carbohydrate research is due to its significance in the biological system, for example, a glycoprotein found in the extracellular matrix, involved in signaling pathways, cell-cell interaction and cell-matrix interaction. Because of the increase in demand of glycolipids for biological applications, in this report, a set of three structurally related gluconamide-based amphiphiles were synthesized from renewable resources, δ-gluconolactone and cashew nut shell liquid. The molecular structure of the synthesized glycolipids was characterized by NMR and mass spectral techniques. Molecular self-assembly of gluconamide-based amphiphiles was investigated relative to the molecular structure and nature of the solvent used. Interestingly, the nature of the hydrophobic tail present in the glycolipids influences the self-assembly pattern, which results in a hydrogel, organogel and highly insoluble nanorods. Gelation studies clearly revealed that the involvement of different magnitude of non-covalent interactions such as hydrogen bonding, π-π stacking and van der Waals interaction. Morphology of self-assembled architecture was investigated by optical microscopy, FESEM and FETEM analysis. The mechanism involved in the molecular self-assembly has been deduced by small angle XRD analysis. Thermo reversibility and the thixotropic nature of the derived gels were identified by rheological measurements. Further, antimicrobial and biofilm inhibitory activity of gluconamide-based amphiphiles were studied against various pathogenic bacterial strains Staphylococcus aureus, Listeria monocytogenes, Salmonella This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

The use of renewable resources to develop functional materials is increasing in order to meet the sustainability challenges. In an era of inexorable evolution of antimicrobial resistance, there is a substantial increase in demand for the development of efficient antimicrobial thin film coating from renewable resources for public bacterial threats, food, biomedical, and industrial applications. In the present investigation, we have used cardanol, a phenolic compound having unsaturated hydrophobic tail isolated from cashew fruits, and linseed oil, a vegetable oil and an important biobased building block, which are cheap and easy to regenerate. This study reports the synthesis of cardanol based metal complexes having unsaturated hydrophobic unit and acrylated epoxidized linseed oil (AELO) prepared via epoxidation of double bonds followed by acrylation. The double bond present in the metal complexes and AELO is prone to form assembled thin film under atmospheric conditions, without the need of any initiators. Assembled thin film is one of the important aspects of nanotechnology holding a wide range of applications. 1H NMR and FT-IR analysis revealed the existence of a strong interaction between ligand and metal, which paves a way to develop a nonleachable metal based thin film coating. The leaching behavior of thin film coating was investigated under various aggressive conditions with the aid of UV–vis spectroscopy. The mechanical properties of assembled thin film coating material composed of cardanol-based metal complex and AELO are described using oscillatory rheology. Morphological and SAXD analysis clearly revealed the formation of the assembled structure in thin films. Thermal response of these materials has been investigated using TGA and DSC measurements. Intrinsic hydrophobic character was identified by contact angle measurement. Antimicrobial and biofilm inhibitory behavior of synthesized compounds and thin films were investigated against various human pathogenic bacterial strains. The assembled thin film coated catheter tube completely inhibits the biofilm formation of uropathogenic Escherichia coli (UPEC). Thus, the developed thin film coating material holds promise to be used as metal enabled, nonleachable coating materials for public bacterial threats, and food and biomedical applications. In particular, this material can be potentially used for developing urinary catheter tubes with antibacterial 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.

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