An optimized measurement chamber for cantilever array measurements in liquid incorporating an automated sample handling system

Abstract

Micro- and nanomechanical analytical devices for diagnostics require small sample volumes, and stable and efficient clamping of the sensors for optimized bioassays. A fully automated device for the readout of the dynamic and static response of cantilevers in a physiological liquid environment including a sample handling system is presented. The device provides sequential readout of the static and dynamic mode providing the best signal to noise ratio for each individual cantilever. In the dynamic mode, it is possible to measure up to the 16th flexural resonance mode of vibration of a 500 μm long and 1 μm thick cantilever. The automated sample handling system enables the local injection of sub microliter volumes of sample with excellent reproducibility. Data demonstrating the response of the cantilevers to external stimuli highlight the sensitivity of the device and the importance of the use of reference cantilevers to decouple biologically relevant metrics from environmental effects. A specific biomolecular interaction of sensitised nanospheres on cantilever sensors with a mass resolution of ~50 picogram in liquid is shown. PACS numbers: 07.10 Mechanical instruments, 87.85 Biosensors, 47.85. Fluidic