Diagnostic approaches based on multimodal imaging are needed for accurate selection of the therapeutic regimens in several diseases, although the dose of administered contrast drugs must be reduced to minimize side effects. Therefore, large efforts are deployed in the development of multimodal contrast agents (MCAs) that permit the complementary visualization of the same diseased area with different sensitivity and different spatial resolution by applying multiple diagnostic techniques. Ideally, MCAs should also allow imaging of diseased tissues with high spatial resolution during surgical interventions. Here a new system based on multifunctional Au-Fe alloy nanoparticles designed to satisfy the main requirements of an ideal MCA is reported and their biocompatibility and imaging capability are described. The MCAs show easy and versatile surface conjugation with thiolated molecules, magnetic resonance imaging (MRI) and computed X-ray tomography (CT) signals for anatomical and physiological information (i.e., diagnostic and prognostic imaging), large Raman signals amplified by surface enhanced Raman scattering (SERS) for high sensitivity and high resolution intrasurgical imaging, biocompatibility, exploitability for in vivo use and capability of selective accumulation in tumors by enhanced permeability and retention effect. Taken together, these results show that Au-Fe nanoalloys are excellent candidates as multimodal MRI-CT-SERS imaging agents.

Magneto-plasmonic nanostructures functionalized with cell targeting units are of great interest for nanobiotechnology applications. Photothermal treatment of cells targeted with antibody functionalized nanostructures and followed by magnetic isolation, allows killing selected cells and hence is one of the applications of great interest. The magneto-plasmonic nanostructures reported herein were synthesized using naked gold and magnetite nanoparticles obtained through a green approach based on laser ablation of bulk materials in water. These particles do not need purifications steps for biocompatibility and are functionalized with a SERRS (surface enhanced resonance Raman scattering) active molecule for detection and with an antibody for targeting prostate tumor cells. Quantitative results for the cell targeting and selection efficiency show an overall accuracy of 94% at picomolar concentrations. The photothermal treatment efficiently kills targeted and magneto-selected cells producing a viability below 5% after 3 min of irradiation, compared with almost 100% viability of incubated and irradiated, but non targeted cells.

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Stable antibody–drug–carbon nanohorns conjugates are able to selectively target and kill prostate cancer cells thanks to a PSMA specific antibody.

Liquid biopsy represents a new frontier of cancer diagnosis and prognosis, which allows the isolation of tumor cells released in the blood stream. The extremely low abundance of these cells needs appropriate methodologies for their identification and enumeration. Herein we present a new protocol based on surface enhanced resonance Raman scattering (SERRS) gold multivalent nanostructures to identify and enumerate tumor cells with epithelial and mesenchimal markers. The validation of the protocol is obtained with spiked samples of peripheral blood mononuclear cells (PBMC). Gold nanostructures are functionalized with SERRS labels and with antibodies to link the tumor cells. Three types of such nanosystems were simultaneously used and the protocol allows obtaining the identification of all individual tumor cells with the help of a Random Forest ensemble learning method.