Biswal Sibani Lisa, Raorane Digvijay, Chaiken Alison, Birecki Henryk, Majumdar Arun
Department of Mechanical Engineering, UC Berkeley, Berkeley, California 94720, USA.
Anal Chem. 2006 Oct 15;78(20):7104-9. doi: 10.1021/ac052171y.
We observe surface stress changes in response to thermal dehybridization, or melting, of double-stranded DNA (dsDNA) oligonucleotides that are grafted on one side of a microcantilever beam. Changes in surface stress occur when one complementary DNA strand melts and diffuses away from the other, resulting in alterations of the electrostatic, counterionic, and hydration interaction forces between the remaining neighboring surface-grafted DNA molecules. We have been able to distinguish changes in the melting temperature of dsDNA as a function of salt concentration and oligomer length. This technique also highlights differences between surface immobilized and solution DNA melting dynamics, which allows us to better understand the stability of DNA on surfaces. The transduction of phase transitions into a mechanical signal is ubiquitous for DNA, making cantilever-based detection a widely useful and complementary alternative to calorimetric and fluorescence measurements.
我们观察到，接枝在微悬臂梁一侧的双链DNA（dsDNA）寡核苷酸发生热解杂交或熔化时，表面应力会发生变化。当一条互补DNA链熔化并从另一条链扩散开时，表面应力就会发生变化，导致剩余相邻表面接枝的DNA分子之间的静电、抗衡离子和水合相互作用力发生改变。我们已经能够区分dsDNA的熔化温度随盐浓度和寡聚物长度的变化。该技术还突出了表面固定化DNA和溶液中DNA熔化动力学之间的差异，这使我们能够更好地理解DNA在表面的稳定性。对于DNA来说，将相变转化为机械信号的过程普遍存在，这使得基于悬臂梁的检测成为量热法和荧光测量的一种广泛有用且互补的替代方法。
