01955nas a2200217 4500008004100000022001400041245007700055210006900132260000800201300001400209490000700223520124600230100001701476700001701493700002101510700002601531700003501557700002101592700001701613856010701630 2016 eng d a1525-779700aSilk fibroin-sophorolipid gelation: deciphering the underlying mechanism0 aSilk fibroinsophorolipid gelation deciphering the underlying mec cOCT a3318-33270 v173 a

Silk fibroin (SF) protein, produced by silkworm Bombyx mori, is a promising biomaterial, while sophorolipid (SL) is an amphiphilic functional biosurfactant synthesized by nonpathogenic yeast Candida bombicola. SL is a mixture of two forms, acidic (ASL) and lactonic (LSL), which when added to SF results in accelerated gelation of silk fibroin. LSL is known to have multiple biological functionalities and hence hydrogels of these green molecules have promising applications in the biomedical sector. In this work, SANS, NMR, and rheology are employed to examine the assembling properties of individual and mixed SLs and their interactions with SF to understand the mechanism that leads to rapid gelation. SANS and NMR studies show that ASL assembles to form charged micelles, while LSL forms micellar assemblies and aggregates of a mass fractal nature. ASL and LSL together form larger mixed micelles, all of which interact differently with SF. It is shown that preferential binding of LSL to SF causes rapid unfolding of the SF chain leading to the formation of intermolecular beta sheets, which trigger fast gelation. Based on the observations, a mechanism for gelation of SF in the presence of different sophorolipids is proposed.

1 aDubey, Parul1 aKumar, Sugam1 aAswal, Vinod, K.1 aRavindranathan, Sapna1 aRajamohanan, Pattuparambil, R.1 aPrabhune, Asmita1 aNisal, Anuya uhttps://library.ncl.res.in/content/silk-fibroin-sophorolipid-gelation-deciphering-underlying-mechanism02000nas a2200301 4500008004100000022001400041245009700055210006900152260000900221300000900230490000800239520101400247653001501261653004401276653000701320653001701327653003501344653001701379100001701396700001701413700002601430700002201456700002101478700003501499700001701534700002101551856012601572 2018 eng d a0254-058400apH dependent sophorolipid assemblies and their influence on gelation of silk fibroin protein0 apH dependent sophorolipid assemblies and their influence on gela cJAN  a9-160 v2033 a

Sophorolipid (SL), a bio-derived surfactant is an excellent gelling agent for natural fibrous protein, silk fibroin (SF) leading to potential biomedical applications. Interaction of SF with SL has been shown to accelerate the formation of hydrogel with the rate being dependent on the form of SL used. Here, we examine the effect of pH on SL-SF interaction and gel formation by employing rheology, fluorescence spectroscopy, SANS and NMR. The results indicate that the size of SL assemblies decrease as pH increases from acidic to alkaline and significantly impacts the association of SL and SF. The association of SF and SL is mainly via hydrophobic interactions, with the SL molecules forming bead like structures along the SF chain. The increased charge on the acidic form of SL at higher pH results in greater repulsion between acidic SL molecules, which are bound to the hydrophobic sites of SF, leading to rapid chain unfolding and subsequent gelation. (C) 2017 Elsevier B.V. All rights reserved.

10aAssemblies10aNuclear magnetic resonance spectroscopy10apH10aSilk fibroin10aSmall angle neutron scattering10aSophorolipid1 aDubey, Parul1 aKumar, Sugam1 aRavindranathan, Sapna1 aVasudevan, Sahana1 aAswal, Vinod, K.1 aRajamohanan, Pattuparambil, R.1 aNisal, Anuya1 aPrabhune, Asmita uhttps://library.ncl.res.in/content/ph-dependent-sophorolipid-assemblies-and-their-influence-gelation-silk-fibroin-protein02183nas a2200169 4500008004100000022001400041245012100055210006900176260000800245300001400253490000700267520154000274100002601814700001701840700002601857856013001883 2025 eng d a0743-746300aVisible light-responsive composition-dependent morphology and cargo release in mixed micelles of dendron amphiphiles0 aVisible lightresponsive compositiondependent morphology and carg cJAN a1957-19670 v413 a

2,2-Bis-(methylol)propionic acid-based second-generation polyester dendron amphiphile (T-D) containing visible light-responsive donor-acceptor Stenhouse adduct (DASA) as hydrophobic tails is synthesized. Micelles of T-D amphiphile and its mixed micelles of varying compositions with nonresponsive dendron amphiphile containing lauryl groups are prepared in aqueous solution. In transmission electron microscopy and atomic force microscopy analyses, T-D amphiphiles show rice grain-like ellipsoidal micelles as the predominant morphology. Mixed micelles display a composition-dependent morphology gradient such that the morphology changes from rice grain like to mixed to completely spherical with decreasing content of the T-D amphiphile. Complete morphology change to spherical micelles and partial reversal to ellipsoidal micelles, finally leading to ill-defined aggregates, are observed when the T-D amphiphile micelles are subjected to visible light-dark storage photoswitching cycles. Small-angle neutron scattering (SANS) analysis of 1 wt.% micellar solution in THF:water (10:90) reveals only a minor change in shape and size upon photoirradiation, and the data could be fitted to spherical or ellipsoidal model. Release of hydrophobic dye from mixed micelles is tuned by the content of the photoresponsive amphiphile. Cellular uptake and visible light-triggered release of hydrophobic drug from mixed micelles are demonstrated using MDA-MB-231 cells, suggesting their applicability for photoresponsive drug delivery.

1 aAvhad, Shankarrao, V.1 aKumar, Sugam1 aAmbade, Ashootosh, V. uhttps://library.ncl.res.in/content/visible-light-responsive-composition-dependent-morphology-and-cargo-release-mixed-micelles