Gonsalves M, Barker A L, Macpherson J V, Unwin P R, O'Hare D, Winlove C P
Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom.
Biophys J. 2000 Mar;78(3):1578-88. doi: 10.1016/S0006-3495(00)76710-5.
The use of scanning electrochemical microscopy, a high-resolution chemical imaging technique, to probe the distribution and mobility of solutes in articular cartilage is described. In this application, a mobile ultramicroelectrode is positioned close ( approximately 1 microm) to the cartilage sample surface, which has been equilibrated in a bathing solution containing the solute of interest. The solute is electrolyzed at a diffusion-limited rate, and the current response measured as the ultramicroelectrode is scanned across the sample surface. The topography of the samples was determined using Ru(CN)(6)(4-), a solute to which the cartilage matrix was impermeable. This revealed a number of pit-like depressions corresponding to the distribution of chondrocytes, which were also observed by atomic force and light microscopy. Subsequent imaging of the same area of the cartilage sample for the diffusion-limited reduction of oxygen indicated enhanced, but heterogeneous, permeability of oxygen across the cartilage surface. In particular, areas of high permeability were observed in the cellular and pericellular regions. This is the first time that inhomogeneities in the permeability of cartilage toward simple solutes, such as oxygen, have been observed on a micrometer scale.
本文描述了使用扫描电化学显微镜（一种高分辨率化学成像技术）来探测溶质在关节软骨中的分布和流动性。在该应用中，一个可移动的超微电极被放置在距离软骨样品表面很近（约1微米）的位置，该软骨样品已在含有感兴趣溶质的浴液中达到平衡。溶质以扩散限制速率进行电解，当超微电极在样品表面扫描时测量电流响应。使用软骨基质不可渗透的溶质Ru(CN)(6)(4-)确定样品的形貌。这揭示了一些对应于软骨细胞分布的坑状凹陷，原子力显微镜和光学显微镜也观察到了这些凹陷。随后对软骨样品同一区域进行氧的扩散限制还原成像，结果表明氧在软骨表面的渗透性增强但不均匀。特别是，在细胞区域和细胞周围区域观察到高渗透性区域。这是首次在微米尺度上观察到软骨对诸如氧等简单溶质的渗透性存在不均匀性。
