02434nas a2200277 4500008004100000022001400041245011600055210006900171260000900240300001200249490000800261520151600269653001501785653001501800653002801815653002701843653001501870653002001885100001801905700002101923700001701944700001701961700002201978700002402000856013202024 2020 eng d a0141-813000aStructural and physical analysis of underwater silk from housing nest composites of a tropical chironomid midge0 aStructural and physical analysis of underwater silk from housing cNOV  a934-9420 v1633 a

Chironomids are an abundant group of aquatic silk spinning insects. They offer a unique opportunity of silk harvestation without killing them; however, they remained underappreciated models in silk research. Here, we investigate the structural and biomechanical characteristics of silk from the midge, Chironomus ramosus. A combination of microscopic (SEM), spectroscopic (CD and IR), structural (XRD), thermal (DSC and TGA) and mechanical measurement tools and techniques were employed to gain critical insights on midge silk. Maximum yield of silk was obtained from Chironomus in similar to 2.5 h, the shortest time reported among insects. The network of water-insoluble silk fibres possessed the smallest diameter of 110 +/- 35 nm, known for any insect silk, qualifying its superiority in fibre fineness. We demonstrate a cruelty-free silk extraction method in contrast to the conventional violent techniques. Structural characterization indicated coexistence of various secondary conformations, beta sheets being predominant. We compare and contrast these features to well-characterized caddisfly and silk-worm silks and highlight the uniqueness in midge silk that render mechanical stability and potentially contribute to its multi-functionalization. We thus propose Chironomus as an emerging candidate of water-borne silk, especially in the context of the `Peace silk' industry, aiming to develop non-violent methods for silk harvestation from animals. (C) 2020 Elsevier B.V. All rights reserved.

10abiopolymer10aChironomus10aCommercial applications10aHousing nest composite10aPeace silk10aUnderwater silk1 aThorat, Leena1 aJoseph, Emmanuel1 aNisal, Anuya1 aShukla, Ekta1 aRaviKumar, Ameeta1 aNath, Bimalendu, B. uhttps://library.ncl.res.in/content/structural-and-physical-analysis-underwater-silk-housing-nest-composites-tropical-chironomid02695nas a2200181 4500008004100000022001400041245009400055210006900149260000900218300001400227490000700241520205600248100002102304700002902325700002202354700001702376856012002393 2021 eng d a0743-746300aMechanism of adhesion of natural polymer coatings to chemically modified siloxane polymer0 aMechanism of adhesion of natural polymer coatings to chemically  cMAR  a2974-29840 v373 a

Surface coatings play an important role in improving the performance of biomedical implants. Polydimethylsiloxane (PDMS) is a commonly used material for biomedical implants, and surface-coated PDMS implants frequently face problems such as delamination or cracking of the coating. In this work, we have measured the performance of nano-coatings of the biocompatible protein polymer silk fibroin (SF) on pristine as well as modified PDMS surfaces. The PDMS surfaces have been modified using oxygen plasma treatment and 3-amino-propyltriethoxy-silane (APTES) treatment. Although these techniques of PDMS modification have been known, their effects on adhesion of SF nano-coatings have not been studied. Interestingly, testing of the coated samples using a bulk technique such as tensile and bending deformation showed that the SF nano-coating exhibits improved crack resistance when the PDMS surface has been modified using APTES treatment as compared to an oxygen plasma treatment. These results were validated at the microscopic and mesoscopic length scales through nano-scratch and nano-indentation measurements. Further, we developed a unique method using modified atomic force microscopy to measure the adhesive energy between treated PDMS surfaces and SF molecules. These measurements indicated that the adhesive strength of PDMS-APTES-SF is 10 times more compared to PDMS-O-2-SF due to the higher number of molecular linkages formed in this nanoscale contact. This lower number of molecular linkages in the PDMS-O-2 indicates that only fewer numbers of surface hydroxyl groups interact with the SF protein through secondary interactions such as hydrogen bonding. On the other hand, a larger number of amine groups present on PDMS-APTES surface hydrogen bond with the polar amino acids present on the silk fibroin protein chain, resulting in better adhesion. Thus, APTES modification to the PDMS substrate results in improved adhesion of nano-coating to the substrate and enhances the delamination and crack resistance of the nano-coatings.

1 aJoseph, Emmanuel1 aRajput, Shatruhan, Singh1 aPatil, Shivprasad1 aNisal, Anuya uhttps://library.ncl.res.in/content/mechanism-adhesion-natural-polymer-coatings-chemically-modified-siloxane-polymer02121nas a2200277 4500008004100000022001400041245011800055210006900173260000900242300001600251490000600267520114500273653002201418653002901440653002001469653004901489653002201538100002101560700002101581700001801602700002301620700001701643700003401660700002301694856012601717 2021 eng d a2168-048500aOne-pot bioconversion of tomato waste into poly-gamma-glutamic acid (gamma-PGA) biopolymer by a novel biocatalyst0 aOnepot bioconversion of tomato waste into polygammaglutamic acid cNOV  a14330-143340 v93 aLandfilling of rotten tomatoes can lead to environmental instability and a huge economic loss to the producers. This letter reports an effective valorization of tomato waste into a promising biopolymer, i.e., poly-gamma-glutamic acid (gamma-PGA) by a novel biocatalyst Bacillus paralicheniformis NCIM 5769. The gamma-PGA is one of the most expensive biopolymers with multifarious applications in wound healing, drug delivery, and regenerative medicine fields. However, its adoption into various applications is finite due to its exorbitant production cost. Herein, rotten tomatoes (without additional nutrient supplementation) served as the chassis for the fermentative production of 40 g/L of highly pure gamma-PGA within 48 h at ambient temperature. Further, NMR, DSC, and TGA confirmed the purity of synthesized gamma-PGA identical to standard gamma-PGA. This process has potential in the commercialization of.-PGA by significantly reducing the production cost, followed by the effective utilization of tomato waste leading to United Nations Sustainable Development Goal 12 (i.e., ensure sustainable consumption and production patterns).10aCommercialization10aPoly-gamma-glutamic acid10aRotten tomatoes10aUnited Nations Sustainable Development Goals10aWaste utilization1 aNair, Pranav, G.1 aJoseph, Emmanuel1 aKilli, Naresh1 aKonchada, Sravanya1 aNisal, Anuya1 aGundloori, Rathna, Venkata Na1 aDharne, Mahesh, S. uhttps://library.ncl.res.in/content/one-pot-bioconversion-tomato-waste-poly-gamma-glutamic-acid-gamma-pga-biopolymer-novel02198nas a2200241 4500008004100000245009300041210006900134260000800203300001100211490000700222520140600229653001701635653002101652653002301673653002401696653001701720100002101737700001801758700002001776700001701796700001901813856012401832 2022 eng d00aSilk fibroin and recombinant elastin blend nano-coatings for implantable medical devices0 aSilk fibroin and recombinant elastin blend nanocoatings for impl cDEC a1048750 v333 a

Silicone breast implants are conventionally used to reconstruct the shape and size of the breast in breast cancer patients. However, rate of failure of implants due to formation of capsular contracture is significantly high. Recent studies have shown that coating the surface of the implant with a biocompatible polymer can mitigate this risk. Here, we have modified the surface of implant using a biocompatible natural biopolymer silk fibroin (SF). Further, we have developed formulations of SF with a recombinantly produced elastin-like-peptide (ELP) and compared their performance with a known anti-fouling hydrophilic polymer - polyethylene oxide (PEO). Microscopic and spectroscopic characterization confirm the formation of uniform coatings. These coatings have been also characterized for their ability to resists crack formation. Further, the coatings have been evaluated for their biological performance. Our studies show that addition of 25 wt% of ELP to SF significantly enhances the crack resistance for the coatings. In addition, SF/ELP coatings reduce the adsorption of blood plasma proteins by more than 80 %. Preliminary analysis shows that the SF/ELP blend coatings are non-cytotoxic and support adhesion, growth and proliferation of fibroblast cells. The study therefore demonstrates that SF/ELP coatings have the potential to mitigate the risk of breast implant failure.

10aBlood plasma10aCrack resistance10aProtein adsorption10aRecombinant elastin10aSilk fibroin1 aJoseph, Emmanuel1 aKane, Kartiki1 aParekh, Nimisha1 aNisal, Anuya1 aJanorkar, Amol uhttps://library.ncl.res.in/content/silk-fibroin-and-recombinant-elastin-blend-nano-coatings-implantable-medical-devices02466nas a2200253 4500008004100000022001400041245011700055210006900172260000800241300001600249490000600265520162400271653001501895653001901910653002401929653001601953653001701969100001501986700002102001700002002022700001702042700002502059856012802084 2022 eng d a2637-610500aViscoelastic liquid from regenerated silk fibroin in the silk i conformation: a writeable and shapeable material0 aViscoelastic liquid from regenerated silk fibroin in the silk i  cJUN a4699–47080 v43 a

Regenerated silk fibroin (RSF) has acquired enormous attention because of its exceptional toughness, strength, and biocompatible nature. These properties make RSF a potential candidate for the fabrication of different types of materials. However, processing even a dilute aqueous solution of RSF leads to a conformational transformation from a random coil/helix-rich (silk I) to a beta-sheetrich (silk II) state. As a consequence, RSF tends to form aggregates and loses its toughness. Working in a direction to address this problem, an aqueous solution of regenerated silk fibroin has been modified with a dual layer of polyethylenimine (PEI) and a PEG-based polymer surfactant (PS). Upon freeze-drying, the RSF-polymer complex forms a solvent-free RSF bioconjugate system and exhibits a soft solid to liquid melting transition at similar to 45 degrees C. The sequential modification with PEI and PS preserves the native-like random coil conformation of RSF up to at least 8 months of storage by not allowing interchain interactions that can lead to aggregation. Rheological and small-angle X-ray scattering measurements show that the solvent-free system is viscoelastic and exhibits a higher order microstructure mediated by the packing of the PS chains, respectively. Temperature-dependent soft solid-liquid-like dual behavior offers applications in injection-based writing, compression molding, and shaping RSF bioconjugates into various types of geometries. Furthermore, the mechanical properties of the RSF bioconjugate system can be modulated by crosslinking with glutaraldehyde vapor at 50 degrees C.

10aRSF liquid10aRSF soft solid10asilk I conformation10asilk liquid10aviscoelastic1 aKumar, Raj1 aJoseph, Emmanuel1 aChaudhari, Atul1 aNisal, Anuya1 aSharma, Kamendra, P. uhttps://library.ncl.res.in/content/viscoelastic-liquid-regenerated-silk-fibroin-silk-i-conformation-writeable-and-shapeable