Biomolecular detection with a thin membrane transducer.
We present a thin membrane transducer (TMT) that can detect nucleic acid based biomolecular reactions including DNA hybridization and protein recognition by aptamers. Specific molecular interactions on an extremely thin and flexible membrane surface cause the deflection of the membrane due to surface stress change which can be measured by a compact capacitive circuit. A gold-coated thin PDMS membrane assembled with metal patterned glass substrate is used to realize the capacitive detection. It is demonstrated that perfect match and mismatch hybridizations can be sharply discriminated with a 16-mer DNA oligonucleotide immobilized on the gold-coated surface. While the mismatched sample caused little capacitance change, the perfectly matched sample caused a well-defined capacitance decrease vs. time due to an upward deformation of the membrane by a compressive surface stress. Additionally, the TMT demonstrated the single nucleotide polymorphism (SNP) capabilities which enabled a detection of mismatching base pairs in the middle of the sequence. It is intriguing that the increase of capacitance, therefore a downward deflection due to tensile stress, was observed with the internal double mismatch hybridization. We further present the detection of thrombin protein through ligand-receptor type recognition with 15-mer thrombin aptamer as a receptor. Key aspects of this detection such as the effect of concentration variation are investigated. This capacitive thin membrane transducer presents a completely new approach for detecting biomolecular reactions with high sensitivity and specificity without molecular labelling and optical measurement.
Cha
Misun
M
School of Mechanical and Aerospace Engineering, Seoul National University, San 56-1, Shinlim, Kwanak, Seoul, 151-742, Korea.
Shin
Jaeha
J
Kim
June-Hyung
JH
Kim
Ilchaek
I
Choi
Junbo
J
Lee
Nahum
N
Kim
Byung-Gee
BG
Lee
Junghoon
J
D052157:Aptamers, Nucleotide / Q000032:analysis* / Q000737:chemistry; D020137:Base Pair Mismatch / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004247:DNA / Q000032:analysis* / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D008567:Membranes, Artificial; D009693:Nucleic Acid Hybridization; D020641:Polymorphism, Single Nucleotide; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D013917:Thrombin / Q000032:analysis* / Q000737:chemistry; D013997:Time Factors; D014159:Transducers
D052157:Aptamers, Nucleotide; D008567:Membranes, Artificial; D011506:Proteins; D006046:Gold; D004247:DNA; D013917:Thrombin