title: Micromechanical detection of proteins using aptamer-based receptor molecules.
abstract: 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.
authors.affiliation: Division of Biological Engineering, Media Laboratory, Massachusetts Institute of Technology, 20 Ames Street E15-422, Cambridge, Massachusetts 02139, USA.
authors.forename: Cagri A
authors.initials: CA
authors.lastname: Savran
authors.forename: Scott M
authors.initials: SM
authors.lastname: Knudsen
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Ellington
authors.forename: Scott R
authors.initials: SR
authors.lastname: Manalis
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004256:DNA Polymerase I / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D011485:Protein Binding; D011506:Proteins / Q000032:analysis*
chemical_list: D009838:Oligodeoxyribonucleotides; D011506:Proteins; D004247:DNA; D004256:DNA Polymerase I