Gross Andreas, Torge Afra, Schaefer Ulrich F, Schneider Marc, Lehr Claus-Michael, Wagner Christian
Experimental Physics, Saarland University, Campus, 66123 Saarbrücken, Germany.
Biopharmaceutics and Pharmaceutical Technology, Department of Pharmacy, Saarland University, Campus, 66123 Saarbrücken, Germany.
J Mech Behav Biomed Mater. 2017 Jul;71:216-222. doi: 10.1016/j.jmbbm.2017.03.009. Epub 2017 Mar 16.
Native horse mucus is characterized with micro- and macrorheology and compared to hydroxyethylcellulose (HEC) gel as a model. Both systems show comparable viscoelastic properties on the microscale and for the HEC the macrorheology is in good agreement with the microrheology. For the mucus, the viscoelastic moduli on the macroscale are several orders of magnitude larger than on the microscale. Large amplitude oscillatory shear experiments show that the mucus responds nonlinearly at much smaller deformations than HEC. This behavior fosters the assumption that the mucus has a foam like structure on the microscale compared to the typical mesh like structure of the HEC, a model that is supported by cryogenic-scanning-electron-microscopy (CSEM) images. These images allow also to determine the relative amount of volume that is occupied by the pores and the scaffold. Consequently, we can estimate the elastic modulus of the scaffold. We conclude that this particular foam like microstructure should be considered as a key factor for the transport of particulate matter which plays a central role in mucus function with respect to particle penetration.
天然马黏液通过微观和宏观流变学进行表征，并与作为模型的羟乙基纤维素（HEC）凝胶进行比较。在微观尺度上，两个体系表现出可比的粘弹性特性，对于HEC而言，宏观流变学与微观流变学高度吻合。对于黏液，宏观尺度上的粘弹性模量比微观尺度上的大几个数量级。大振幅振荡剪切实验表明，与HEC相比，黏液在小得多的变形下就会产生非线性响应。这种行为促使人们推测，与HEC典型的网状结构相比，黏液在微观尺度上具有类似泡沫的结构，低温扫描电子显微镜（CSEM）图像支持了这一模型。这些图像还能确定孔隙和支架所占的相对体积。因此，我们可以估算支架的弹性模量。我们得出结论，这种特殊的类似泡沫的微观结构应被视为颗粒物运输的关键因素，而颗粒物运输在黏液关于颗粒渗透的功能中起着核心作用。
