  A novel bio-photonics approach based on the nonlinear optical process of
second harmonic generation by non-centrosymmetric nanoparticles is presented
and demonstrated on malignant human cell lines. The proposed method allows to
directly interact with DNA in absence of photosensitizing molecules, to enable
independent imaging and therapeutic modalities switching between the two modes
of operation by simply tuning the excitation laser wavelength, and to avoid any
risk of spontaneous activation by any natural or artificial light source.
