An electromagnetically-actuated polymer micro-pen for picoliter biological assay patterning

This paper reports a polymer micro-pen with an integrated microchannel and a sample reservoir, which can be actuated by Lorentz force induced on an integrated metal actuator for biological assay patterning. The length, width and thickness of the micro-pen are 500/spl mu/m, 120/spl mu/m and 6/spl mu/m, respectively. The fabricated micro-pen is successfully deflected by electromagnetic force from external permanent magnets which generates a magnetic field of 0.2T. Spring constant of the micro-pen is analytically estimated as 1.9N/m and the measured resonance frequency is about 7.3 kHz. The microchannel formed on this polymer micro-pen is 15/spl mu/m wide and the sample reservoir is 500/spl mu/m thick in the area of 300/spl mu/m/spl times/300/spl mu/m. Red ink is pulled up to the end point of the microchannel from the reservoir by capillary force. A red-ink-dot in diameter of 11 /spl mu/m has been placed on paper by the fabricated micro-pen. This demonstrates a sub-picoliter patterning of biological assay is possible.