Attaching Single Biomolecules Selectively to the Apex of AFM Tips for Measuring Specific Interactions
Jianhua Gu 1, Zhongdang Xiao 1, Chi-Ming Yam 1, Guoting Qin 1, Maxence Deluge 1, Sabine Boutet 1 and Chengzhi Cai 1*
1 University of Houston
* To whom correspondence should be addressed. E-mail: cai{at}uh.edu.
Submitted on June 21, 2005
Revised on June 28, 2005
Accepted on 9 August 2005
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Abstract |
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We present a general approach for preparing well-defined AFM tips for probing single target molecules. We showed that carboxylic acid groups could be generated by electrochemical oxidation selectively at the apex of an AFM tip that are coated with a monolayer of oligo(ethylene glycol) derivatives for resisting non-specific interactions. These carboxylic acid groups were used as handles to tether possibly only one ligand molecule, such as biotin, to the tip apex for measurement of specific interactions.
Key Words:
AFM cantilever tips, biomolecular interactions, force titration, local electrochemical oxidation, non-specific interactions, oligo(ethylene glycol)s