Narayanan Ganesh, Gupta Bhupender S, Tonelli Alan E
Fiber & Polymer Science Program, North Carolina State University , Raleigh, North Carolina 27695-8301, United States.
Biomacromolecules. 2014 Nov 10;15(11):4122-33. doi: 10.1021/bm501158w. Epub 2014 Oct 23.
The effects of alpha- and gamma-cyclodextrins (α- and γ-CDs) on the thermal and crystal nucleation behavior of electrospun poly(ε-caprolactone) (PCL) nanofibers have been investigated. PCL/CD composite nanofibers were obtained for the first time by electrospinning the mixture from chloroform/N,N-dimethylformamide (60:40). Scanning electron microscopy analyses indicated that neat PCL nanofibers have an average diameter of 400 nm, which increases with the addition of CDs. The presence of CDs on or in the electrospun PCL fibers in the electrospun mats was investigated using Fourier transform infrared spectroscopy, thermogravimetric analysis, and wide-angle X-ray diffraction analysis. Differential scanning calorimetry showed that the PCL/CD composite fibers exhibit higher crystallization temperatures and sharper crystallization exotherms with increased CD loading, indicating the ability of CDs to nucleate PCL crystallization. Water contact angle (WCA) measurements indicate an inverse relationship between WCA and α- or γ-CD concentration up to 30% loading. Phenolphthalein absorption tests were performed to study the kinetics of their inclusion complex (IC) formation with CDs. Unexpectedly, γ-CD-functionalized nanowebs performed better than α-CD. This might be because at elevated loadings some α-CDs may have threaded over PCL chains and formed ICs, whereas γ-CD did not. With their encapsulation capabilities and their lowered hydrophobicity, PCL/CD composite fibers might have potential uses in medical applications, in particular as wound odor absorbants in dressings, because it is well known that CDs can form ICs with these odorants, thereby effectively removing them.
研究了α-环糊精和γ-环糊精（α-CD和γ-CD）对静电纺聚己内酯（PCL）纳米纤维的热行为和晶体成核行为的影响。通过将氯仿/N，N-二甲基甲酰胺（60:40）的混合物进行静电纺丝，首次获得了PCL/CD复合纳米纤维。扫描电子显微镜分析表明，纯PCL纳米纤维的平均直径为400nm，随着CD的添加而增加。使用傅里叶变换红外光谱、热重分析和广角X射线衍射分析研究了静电纺垫中静电纺PCL纤维上或纤维内CD的存在情况。差示扫描量热法表明，PCL/CD复合纤维随着CD负载量的增加呈现出更高的结晶温度和更尖锐的结晶放热峰，表明CD具有促进PCL结晶成核的能力。水接触角（WCA）测量表明，在负载量高达30%时，WCA与α-或γ-CD浓度呈反比关系。进行了酚酞吸收试验以研究它们与CD形成包合物（IC）的动力学。出乎意料的是，γ-CD功能化纳米网的性能优于α-CD。这可能是因为在较高负载量下，一些α-CD可能缠绕在PCL链上并形成IC，而γ-CD则没有。由于其包封能力和降低的疏水性，PCL/CD复合纤维在医疗应用中可能具有潜在用途，特别是作为敷料中的伤口气味吸收剂，因为众所周知，CD可以与这些气味剂形成IC，从而有效去除它们。
