Lavén Martin, Velikyan Irina, Djodjic Majda, Ljung Jenny, Berglund Oskar, Markides Karin, Långström Bengt, Wallenborg Susanne
Department of Analytical Chemistry, Institute of Chemistry, Uppsala University, Box 599, 751 24 Uppsala, Sweden.
Lab Chip. 2005 Jul;5(7):756-63. doi: 10.1039/b418715f. Epub 2005 May 31.
A method for studying peptide-surface interactions within microfluidic channels by radionuclide imaging is described. With the high surface area-to-volume ratio of channels in miniaturised devices, combined with low amounts of analyte, non-specific peptide adsorption is a critical issue. The objective of the study was therefore to develop a method capable of direct detection of adsorbed peptide within microfluidic channels. A micro-device consisting of channels moulded in a plastic compact disc was chosen for the study, together with two selected peptides of different lengths and isoelectric point (pI) values. A bifunctional chelator, DOTA, was attached to the peptide by conjugation and labelled with the short-lived positron emitting radionuclide 68Ga. Quantitative images of radiotracer distribution within the microfluidic channels were obtained using a PhosphorImager system. The power of the method was demonstrated by the ability to clearly measure changes in adsorption when varying a number of parameters that typically affect peptide adsorption. These included surface modifications, analyte concentration, pH, and ionic strength. Additionally, two quantification methods were developed and compared. Radionuclide imaging also permitted visualisation of adsorption and release processes in microchannel chromatographic columns. The results suggest that radionuclide imaging is a suitable tool not only for the study of peptide adsorption to the microchannels presented in this study but also as a versatile tool to measure peptide-surface interactions in a wide variety of miniaturised structures and devices.
本文描述了一种通过放射性核素成像研究微流控通道内肽与表面相互作用的方法。由于小型化设备中通道的表面积与体积之比很高，再加上分析物的量很少，非特异性肽吸附是一个关键问题。因此，本研究的目的是开发一种能够直接检测微流控通道内吸附肽的方法。本研究选用了一种由塑料光盘模制而成的微设备，以及两种不同长度和等电点（pI）值的选定肽。通过共轭将双功能螯合剂DOTA连接到肽上，并用短寿命正电子发射放射性核素68Ga进行标记。使用磷光成像系统获得微流控通道内放射性示踪剂分布的定量图像。通过改变一些通常影响肽吸附的参数时能够清晰测量吸附变化的能力，证明了该方法的有效性。这些参数包括表面修饰、分析物浓度、pH值和离子强度。此外，还开发并比较了两种定量方法。放射性核素成像还可以观察微通道色谱柱中的吸附和释放过程。结果表明，放射性核素成像不仅是研究本研究中微通道肽吸附的合适工具，也是测量各种小型化结构和设备中肽与表面相互作用的通用工具。
