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Single needle electrode-topped amplifier package (STACK) for in vivo applications

We propose a single needle-topped amplifier package, so called STACK device, for use in a low invasive and a high signal-to-noise ratio neuronal recording from brain in vivo. Advantages of the proposed device include i) device minimization, ii) simplified on-chip MOS amplifier integration, and iii) the high device yield. The STACK device can be simply assembled by stacking three components: microneedle-electrode module, MOSFET amplifier module, and flexible interposer (Fig.1). The overall device geometry is ∼ 1 × 1 mm2 (∼ 1 mm in thickness), which size is applicable to small brain tissues, such as mice. The microneedle with a high impedance characteristic shows the signal-amplitude attenuation, which is improved by stacking the amplifier module. We also confirmed the neuronal recording capability of the STACK device, as demonstrated in the recording using a mouse's brain in vivo.