A new spray based ambient ionization method has been developed for point by point disease state diagnosis of tissue. Touch spray ionization utilizes a suitable roughened metal probe, such as a teasing needle, to physically touch and remove a small amount of material from an area of interest. The probe is used to transfer material from its point of origin to the entrance of a mass spectrometer where high voltage and solvent are applied to the probe. Solvent flows over the material on the probe and creates a Taylor cone carrying extracted molecules into the mass spectrometer for chemical analysis. Negative mode mass spectra produced with touch spray on mouse brain sections show similar lipid patterns to desorption electrospray ionization (DESI) with dominant ions at m/z 788, 834, 885, and 888 in characteristic ratios for white or gray matter. Chemical mapping of coronal, sagittal, and transverse mouse brain sections have been performed to show reproducibility, specificity, and differentiation of the tissue when probing different areas of the brain. Recently, in collaboration with Indiana University's School of Medicine (IUSM), fresh cancerous specimens have been obtained from radical prostatectomy or partial nephrectomy surgeries and investigated with touch spray probes for rapid in vitro analysis. It is envisioned that touch spray may be used to probe tissue of interest in vivo and ex vivo producing disease state results under a minute during surgery.

Touch spray ambient ionization for spot analysis of tissue disease state

246th National Meeting (2013)

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