Lee Jae-Ho, Agarwal Vivek, Bose Arijit, Payne Gregory F, Raghavan Srinivasa R
Department of Chemical Engineering, University of Maryland, College Park, Maryland 20742-2111, USA.
Phys Rev Lett. 2006 Feb 3;96(4):048102. doi: 10.1103/PhysRevLett.96.048102. Epub 2006 Jan 31.
We report some unusual structural transitions upon the addition of an amphiphilic biopolymer to unilamellar surfactant vesicles. The polymer is a hydrophobically modified chitosan and it embeds its hydrophobes in vesicle bilayers. We study vesicle-polymer mixtures using small-angle neutron scattering (SANS) and cryotransmission electron microscopy (cryo-TEM). When low amounts of the polymer are added to unilamellar vesicles of ca. 120 nm diameter, the vesicle size decreases by about 50%. Upon further addition of polymer, lamellar peaks are observed in the SANS spectra at high scattering vectors. We show that these spectra correspond to a co-existence of unilamellar and bilamellar vesicles. The transition to bilamellar vesicles as well as the changes in unilamellar vesicle size are further confirmed by cryo-TEM. A mechanism for the polymer-induced transitions in vesicle morphology is proposed.
我们报道了在向单层表面活性剂囊泡中添加两亲性生物聚合物时发生的一些不寻常的结构转变。该聚合物是一种疏水改性壳聚糖，它将其疏水基团嵌入囊泡双层中。我们使用小角中子散射（SANS）和低温透射电子显微镜（cryo-TEM）研究囊泡-聚合物混合物。当向直径约120 nm的单层囊泡中添加少量聚合物时，囊泡尺寸减小约50%。进一步添加聚合物后，在高散射矢量的SANS光谱中观察到层状峰。我们表明这些光谱对应于单层和双层囊泡的共存。低温透射电子显微镜进一步证实了向双层囊泡的转变以及单层囊泡尺寸的变化。提出了聚合物诱导囊泡形态转变的机制。
