CANCER DIAGNOSIS & TREATMENT/NANOTECHNOLOGY: Nanostructures improve disease detection and photodynamic cancer therapy

Nanotechnology is at the basis of a new initiative and a recently announced discovery, both originating in Europe.

Propelling PDT

CEA-Leti's (Grenoble, France) TARGET-PDT project, launched in June, aims to increase the effectiveness of photodynamic therapy (PDT) for cancer–by developing a novel nano carrier-based approach.

PDT has shown significant potential for improving cancer treatment: It offers strictly focused application, biocompatibility with other forms of therapy, the option for repeated use, excellent cosmetic and functional outcomes, and fast recovery. But the use of PDT has been hampered by limited effectiveness of photosensitizers reaching the tumor and potential collateral damage. So the CEA-Leti project will study the delivery and targeting of photosensitizers encapsulated into lipid nano-particles that will also include antibodies to target specific biomarkers. TARGET-PDT will focus on bone cancer and head-and-neck squamous cell carcinoma, for which current treatments often produce terrible side effects, poor functional outcomes, and low cure rates.

The project will allow the partners to study all aspects of PDT treatment: nano-carrier size and payload, photosensitizers such as chlorines and phthalocyanines, targeting method and types of laser irradiation. The experimental approach will be developed into a preclinical validation to deliver an optimized combination for first clinical "nano-PDT" at a later stage. By using nanotechnology-based photosensitizer delivery systems, the project will set the stage for improved control of the therapy and more comfort for cancer patients.

Boosting biosensors

A discovery by researchers at Imec (Leuven, Belgium) paves the way to early diagnostics of cancer, for example, and shows that shape matters for disease detection. Based on work done with the Catholic University of Leuven (Leuven, Belgium), Imperial College (London) and Rice University (Houston, TX), the Imec team demonstrated that surface plasmon resonance (SPR) enables detection of a change in spectral response of nanostructures engineered to bind to a disease marker. Changing the morphology and size of gold and silver nanostructures can increase detection sensitivity in inexpensive SPR-based biosensor systems, enabling detection of low densities of biomarkers in human blood samples.

The researchers demonstrated that combining different structures–such as nanorings with nanodiscs–in close proximity allows detailed engineering of the biosensors' plasmon resonance. Specifically, the imec team targeted an optimization of both the width of the resonance peak and the resonance shift upon binding of the disease marker. The new geometries clearly outperformed traditional nanospheres, and thus are better suited for practical use in biosensor systems–which can be easily extended to detect multiple parameters.