Water-soluble sacrificial layer enables ultra low-cost LOC integration of magnetic resonance microcoils with 100% filling factor

We present a novel fabrication process for low-cost, high-aspect ratio magnetic resonance (MR) helical transceiver microcoils wound with an automated wirebonder. Previously reported microcoils [1] required a permanent hollow post to stabilise the coil´s wire, but which simultaneously reduced the sample volume, and thus the signal-to-noise ratio (SNR). An image acquired of an ionised water sample (1 g/l CuSO₄) in an 11.7 T spectrometer yields a signal-to-noise ratio of 17 for an in-plane resolution of 15 × 15 μm² in an acquisition time of 05:07 min.