Optical detection of tumor cell aggressiveness by means of 3D silicon micromachined structures.

We investigated the capacity of tumour cells to populate the gaps of three-dimensional microstructures (3D-SMS) formed by periodic arrays of parallel 3-?m-thick silicon walls separated by 5-?m-wide, 50 ?m-deep air gaps. To evaluate a possible correlation between this feature and cell aggressiveness, we tested eight human tumour cell lines with a well known different aggressive potential. The qualitative analysis performed by fluorescence microscopy revealed that some tumour cell lines populate the narrow gaps of the microstructure due to their greater plasticity and enhanced aggressiveness; on the other hand, cells with low aggressive potential are less prone to colonise the gaps. Image analysis of fluorescence microscopy fields allowed the quantification of the fraction of cells inside the gaps over the total cell number. Our results suggest that tumour cell plasticity could be considered as a biomarker of aggressiveness of tumour cells grown in an innovative 3D micro-device characterised by a well-defined and highly reproducible geometrical layout.