Use of the 1-mm micro-probe for metabolic analysis on small volume biological samples

Endogenous metabolites are promising diagnostic end-points in cancer research. Clinical application of high-resolution NMR spectroscopy is often limited by extremely low volumes of human specimens. In the present study, the use of the Bruker 1-mm high-resolution TXI micro-probe was evaluated in the elucidation of metabolic profiles for three different clinical applications with limited sample sizes (body fluids, isolated cells and tissue biopsies). Sample preparation and 1H-NMR metabolite quantification protocols were optimized for following oncology-oriented applications: (i) to validate the absolute concentrations of citrate and spermine in human expressed prostatic specimens (EPS volumes 5 to 10 mu l: prostate cancer application); (ii) to establish the metabolic profile of isolated human lymphocytes (total cell count 4 = 106: chronic myelogenous leukaemia application); (iii) to assess the metabolic composition of human head-and-neck cancers from mouse xenografts (biopsy weights 20 to 70 mg: anti-cancer treatment application). In this study, the use of the Bruker 1-mm micro-probe provides a convenient way to measure and quantify endogenous metabolic profiles of samples with a very low volume/weight/cell count.