In this EAGER project funded by the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Tao Ye at University of California-Merced and his group will use atomic force microscopy (AFM) to visualize the conformational changes and biochemical reactions of DNA molecules that are anchored to electroactive surfaces, i.e., surfaces that dynamically change their affinity with molecular adsorbates under electrochemical control. Such novel dynamic surfaces will help address a long-standing challenge in AFM visualization of biochemical reactions: if the biomacromolecules are pinned down, which is needed for high resolution AFM, the interactions with the surface perturb the reaction. The dynamic surfaces will expand the repertoire of surfaces and reactions that can be probed by single molecule AFM imaging, significantly reduce the measurement artifacts, and improve the imaging resolution. Therefore, the project will further our understanding of the reactions of biomacromolecules at the nanoscale and single molecule level.
The project will train graduate students at the cutting edge of nanoscale measurement and imaging. The proposed research will also provide research opportunities to undergraduate students at UC Merced, many of whom are underrepresented minorities.
With support of this EAGER award, we have developed surfaces that can dynamically change interactions with charged biological molecules such as DNA. We have discovered a novel electroactive self-assembled monolayer surfaces that can reversibly switch interactions in most aqueous buffers. We have also created new methods to attach DNA to self-assembled monolayer surfaces. Intellectual merit: With the development of static surfaces with controlled interactions with biomolecules, there has been an increasing interest in active surfaces whose binding affinity with analytes/ligands can be dynamically regulated with external stimuli. We have showed that a novel electroactive surface can switch interactions with DNA rapidly and reversibly in biological buffers. The electroactive surface allows 30x greater modulation of interaction forces than is possible with traditional nonelectroactive surfaces. The project opens up numerous opportunities in biosensors, separation, and high resolution imaging. In addition, the project has lead to improved understanding of attaching biological molecules to surfaces, which is key to a broad range of biotechnological applications and fundamental biophysical studies. Our new approach can covalently attach DNA to a surface in a sequence specific manner, allowing new opportunities in single molecule measurements. We have also for the first time quantified the damage sustained by DNA during copper catalyzed click chemistry. Broader impacts: The dynamic surfaces may serve as an enabling tool in new biosensing and separation technologies that have potential in commerical applications. The project has trained two Ph.D. students who are well prepared for interdisciplinary challenges in high tech industry and academic research. The project has provided opportunities for undergraduate researchers. Both two students involved have been admitted into highly regarded Ph.D. programs.
