[Preparation of magnetic resonance molecular probe for breast cancer detection in vitro]

To prepare magnetic resonance (MR) molecular probe for somatostain receptor expressed on breast cancer cell membranes and investigate its physico-chemical properties and imaging features in vitro.

Molecular probe was prepared through superparamagnetic iron oxide (SPIO) conjugated to somatostatin analog-octreotide (OCT) using chemical method. Its features at different Fe(2+) concentrations were tested by MTT assay and Prussian blue staining respectively. Molecular probes at different Fe(2+) concentration and various numbers of cells labeled with the probe at Fe(2+) concentrations of 20 mg/L were scanned with 1.5 Tesla MR. Resovist was used in control group when labeling cells.

Various blue-staining particles were found in the cytoplasms of labeled cells with the molecular probes at different concentrations after Prussion blue staining and there were more particles with the increase of Fe(2+) concentration. The label rate of the probe was 96.15% which was higher than that in control group (80.00%). The bioactivity had no difference between labeled and non-labeled cells (P>0.05). There was remarkable low signal intensity on T(2)-weighed imaging and no evident artifacts for molecular probe when the concentration of Fe(2+) was 20 mg/L. The least number of labeled cells detected by MR in vitro was 6 x 10(6) when the concentration of Fe(2+) was 20 mg/L.

Molecular probe, SPIO-OCT, can effectively label breast cells which express SSTR. The reasonable Fe(2+) concentration of labeled cells and imaging was 20 mg/L. There is a correlation between MR signal intensity in vitro and the number of labeled cells.