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Biosurfactants derived from different microbes are an alternative to chemical surfactants, which have broad applications in food, oil, biodegradation, cosmetic, agriculture, pesticide and medicine/pharmaceutical industries. This is due to their environmentally friendly, biocompatible, biodegradable, effectiveness to work under various environmental conditions and non-toxic nature. Lactic acid bacteria (LAB)-derived glycolipid biosurfactants can play a major role in preventing bacterial attachment, biofilm eradication and related infections in various clinical settings and industries. Hence, it is important to explore and identify the novel molecule/method for the treatment of biofilms of pathogenic bacteria. In the present study, a probiotic Lactobacillus rhamnosus (L. rhamnosus) strain was isolated from human breast milk. Firstly, its ability to produce biosurfactants, and its physicochemical and functional properties (critical micelle concentration (CMC), reduction in surface tension, emulsification index (% EI24), etc.) were evaluated. Secondly, inhibition of bacterial adhesion and biofilm eradication by cell-bound biosurfactants from L. rhamnosus was performed against various biofilm-forming pathogens (B. subtilis, P. aeruginosa, S. aureus and E. coli). Finally, bacterial cell damage, viability of cells within the biofilm, exopolysaccharide (EPS) production and identification of the structural analogues of the crude biosurfactant via gas chromatography–mass spectrometry (GC–MS) analysis were also evaluated. As a result, L. rhamnosus was found to produce 4.32 ± 0.19 g/L biosurfactant that displayed a CMC of 3.0 g/L and reduced the surface tension from 71.12 ± 0.73 mN/m to 41.76 ± 0.60 mN/m. L. rhamnosus cell-bound crude biosurfactant was found to be effective against all the tested bacterial pathogens. It displayed potent anti-adhesion and antibiofilm ability by inhibiting the bacterial attachment to surfaces, leading to the disruption of biofilm formation by altering the integrity and viability of bacterial cells within biofilms. Our results also confirm the ability of the L. rhamnosus cell-bound-derived biosurfactant to damage the architecture of the biofilm matrix, as a result of the reduced total EPS content. Our findings may be further explored as a green alternative/approach to chemically synthesized toxic antibiofilm agents for controlling bacterial adhesion and biofilm eradication.

ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. AbstractThere is a need to develop pro-angiogenic biomaterials to promote wound healing and to assist in regenerative medicine. To this end, various growth factors have been exploited which have the potential to promote angiogenesis. However these are generally expensive and labile which limits their effectiveness. An alternative approach is to immobilize heparin onto biocompatible degradable hydrogels. The heparin in turn will then bind endogenous proangiogenic growth factors to induce formation of new blood vessels.In this study we continue our development of hydrogels for wound healing purposes by exploring covalently cross-linking chitosan (CS) and polyvinyl alcohol (PVA) hydrogels using triethyl orthoformate (TEOF) .Two concentrations of TEOF ( 4 and 16 %) were compared for their effects on the structure of hydrogels -their swelling, pore size and rate of degradation and 2 for their ability to support the growth of cells and for their heparin binding capacity and their effects on angiogenesis in a chick chorioantoic membrane assay .Hydrogels formed with 4 or 16% both TEOF cross-linker were equally cyto-compatible.Hydrogels formed with 4% TEOF absorbed slightly more water than those made with 16%TEOF and broke down slightly faster than non-cross-linked hydrogels. When soaked in heparin the hydrogel formed with 16% TEOF showed more blood vessel formation in the CAM assay than that formed with 4% TEOF.

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Processing of peripheral blood progenitor cells (PBPC) for clinical transplantation or research applications aims to effectively isolate or deplete specific cell populations, utilizing primarily magnetic or fluorescence activated sorting methods. Here, we investigated the performance of microfluidic acoustophoresis for the separation of lymphocyte subsets from PBPC, and present a novel method for affinity-beadmediated acoustic separation of cells which can otherwise not be acoustically discriminated. As the acoustic force on a particle depends on particle size, density and compressibility, targeting of cells by affinity specific beads will generate cell-bead complexes that exhibit distinct acoustic properties relative to nontargeted cells and are, thus, possible to isolate. To demonstrate this, PBPC samples (n 5 22) were obtained from patients and healthy donors. Following density gradient centrifugation, cells were labeled with anti-CD4-coated magnetic beads (Dynal) and isolated by acoustophoresis and, for comparison, standard magnetic cell sorting technique in parallel. Targeted CD41 lymphocytes were acoustically isolated with a mean (6SD) purity of 87 6 12%, compared with 96 6 3% for control magnetic sorting. Viability of sorted cells was 95 6 4% (acoustic) and 97 6 3% (magnetic), respectively. The mean acoustic separation efficiency of CD41 lymphocytes to the target fraction was 65 6 22%, compared with a mean CD41 lymphocyte recovery of 56 6 15% for magnetic sorting. Functional testing of targeted CD41 lymphocytes demonstrated unimpaired mitogen-mediated proliferation capacity and cytokine production. Hematopoietic progenitor cell assays revealed a preserved colony forming ability of nontarget cells post sorting. We conclude that the acoustophoresis platform can be utilized to efficiently isolate bead-labeled CD41 lymphocytes from PBPC samples in a continuous flow format, with preserved functional capacity of both target and nontarget cells. These results open up for simultaneous affinitybead-mediated separation of multiple cell populations, something which is not possible with current standard magnetic cell separation technology. V C 2014 International Society for Advancement of CytometryKey terms peripheral blood progenitor cells; PBPC; lymphocytes; magnetic beads; acoustophoresis; ultrasound; cell sorting CELL separation technologies are essential tools in the processing of hematopoietic cells for therapeutic administration, diagnostic purposes or research applications. Separation by centrifugal force is generally employed for primary extraction of leukocytes from whole blood or bone marrow (1), followed by selective affinity methods, such as magnetic activated cell sorting (MACS) (2), or fluorescence activated cell sorting (FACS) (3), for isolation or depletion of specific cell populations. Depending on sample characteristics and the specific cell sorting application, the currently available techniques have distinct advantages as well as disadvantages in terms of recovery, purity, and throughput ...