Micromechanical Detection of Proteins Using Aptamer-Based Receptor Molecules

• Published in: Analytical chemistry (Washington) Vol. 76; no. 11; pp. 3194 - 3198
• Main Authors: Savran, Cagri A, Knudsen, Scott M, Ellington, Andrew D, Manalis, Scott R
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.06.2004
• Subjects: Analytical chemistry; Base Sequence; Biological and medical sciences; Biosensing Techniques; Biosensors; Biotechnology; Deoxyribonucleic acid; DNA; DNA - chemistry; DNA - metabolism; DNA Polymerase I - chemistry; DNA Polymerase I - metabolism; Escherichia coli - chemistry; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Molecular Sequence Data; Oligodeoxyribonucleotides - chemistry; Protein Binding; Proteins; Proteins - analysis; Sensors; Various methods and equipments; Micromechanical devices; Functionalization; Biosensor; DNA; Cantilever beam; Protein
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac049859f

We report label-free protein detection using a microfabricated cantilever-based sensor that is functionalized with DNA aptamers to act as receptor molecules. The sensor utilizes two adjacent cantilevers that constitute a sensor/reference pair and allows direct detection of the differential bending between the two cantilevers. One cantilever is functionalized with aptamers selected for Taq DNA polymerase while the other is blocked with single-stranded DNA. We have found that the polymerase−aptamer binding induces a change in surface stress, which causes a differential cantilever bending that ranges from 3 to 32 nm depending on the ligand concentration. Protein recognition on the sensor surface is specific and has a concentration dependence that is similar to that in solution.