Microcantilever Arrays for Multiplexed Biomolecular Analysis

An accurate, efficient, and quantitative method for detection of multiple biomolecules, such as DNA and proteins, would benefit many bio-medical applications. These applications include diagnostics of complex diseases such as cancer, drug discovery, and development of fundamental scientific knowledge regarding signaling pathways. We have developed a chip-level microcantilever array designed for high-throughput biomolecular analysis. In particular, biological reactions on one surface of a microcantilever beam change its surface tension due to intermolecular energetic and entropic interactions. These interactions generate sufficient torque to deflect the cantilever beam. Integration of microfluid cells on the chip allows for individual functionalization of each cantilever. Each cantilever is designed to respond uniquely to a specific target analyte allowing for simultaneous and quantitative analysis of multiple bio-molecules. Experiments testing the physical response of the microarray describe the repeatability of the cantilevers while providing information regarding the limits on the detection time for reaction-induced deflections to dominate over random drift of the cantilevers. Statistical analysis shows that the cantilevers exhibit thermomechanical sensitivity within ±7% variation. The maximum observed trend of the long-term drift is about 2.1nm/min, which suggests reactions should be completed within 10 minutes, for a reliable bioassay.