@article {45642,
	title = {Silk fibroin-sophorolipid gelation: deciphering the underlying mechanism},
	journal = {Biomacromolecules},
	volume = {17},
	year = {2016},
	month = {OCT},
	pages = {3318-3327},
	type = {Article},
	abstract = {<p>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.</p>},
	issn = {1525-7797},
	doi = {10.1021/acs.biomac.6b01069},
	author = {Dubey, Parul and Kumar, Sugam and Aswal, Vinod K. and Ravindranathan, Sapna and Rajamohanan, Pattuparambil R. and Prabhune, Asmita and Nisal, Anuya}
}
@article {44242,
	title = {pH dependent sophorolipid assemblies and their influence on gelation of silk fibroin protein},
	journal = {Materials Chemistry and Physics},
	volume = {203},
	year = {2018},
	month = {JAN },
	pages = {9-16},
	type = {Article},
	abstract = {<p>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.</p>},
	keywords = {Assemblies, Nuclear magnetic resonance spectroscopy, pH, Silk fibroin, Small angle neutron scattering, Sophorolipid},
	issn = {0254-0584},
	doi = {10.1016/j.matchemphys.2017.09.045},
	author = {Dubey, Parul and Kumar, Sugam and Ravindranathan, Sapna and Vasudevan, Sahana and Aswal, Vinod K. and Rajamohanan, Pattuparambil R. and Nisal, Anuya and Prabhune, Asmita}
}
