Summary

Today, more than half of all cancer patients receive radiotherapy as part of their treatment. However, radiotherapy efficacy is often limited by healthy tissues toxicity and needs to be optimized. One relevant solution is to increase the radiation dose deposition from within the tumor cells. The presence of high atomic number (high-Z) elements within the X-ray pathway increases the probability of interaction with ionizing radiation as compared with tissues (composed of low-Z elements). Likewise, mammalian cells can handle materials at the nanoscale. Therefore, materials made of high-Z elements designed at the nanoscale can enhance the deposit of the radiation dose at the cancer cell level.

Still, the most relevant design of these nano-objects has been scarcely explored. Here, we hypothesize that the packing of high-Z elements within the nano-object is a key parameter when considering its design. We used gold and probe how its packing at the nanoscale can achieve the best probability of interaction with ionizing radiation. […]

Summary

Since the discovery of cisplatin about 40 years ago, the design of innovative metal-based anticancer drugs is a growing area of research. Metal elements offer specific characteristics due to their intrinsic properties and could be used in relation to their final state: a metal complex, a radionuclide, a metal-based nanoparticle product. Transition metal coordination complexes interact with cell molecular targets, affecting biochemical functions resulting in cancer cell destruction. Radionuclides are another way to use metals as anticancer therapy. The metal nucleus of the unstable radionuclide becomes stable by emitting energy. The biological effect in different tissues is obtained by the absorption of this energy from the radiation emitted by the radionuclide, the principal target generally agreed for ionizing radiations being DNA. A new area of clinical research is now emerging using the same experimental metal elements, but in a radically different manner: metals and metal oxides used as crystalline nanosized radiation enhancers particles. The use of metals as a high electron density material tailored at the nanoscale when exposed to radiotherapy is a unique approach that can allow entry to the cell and make feasible the absorption/deposition of a high-energy dose within the tumor cell (on/off activity). Therefore, high electron density metal or metal oxide nanoparticles may bring well known physical mode of action, that of radiotherapy, within malignant cells and achieve the paradigm of local cancer treatment.

Summary

Congress: CLINAM, 23rd May 2011

Contents: The development of new activatable drug nanocarriers, with multiple functionalities, presents a promising approach for cancer treatment.

Improved drug delivery and controlled drug release at the tumor site may have considerable benefit by increasing treatment efficacy while reducing side effects and toxicity. Further, the possibility to monitor both nanocarrier accumulation and drug release via current clinical imaging techniques may be particularly relevant for an optimal treatment.

Within the European project “Sonodrugs”, we investigated the opportunity of triggering the drug release from new nanocarriers (temperature and pressure-sensitive) thanks to High Intensity Focused Ultrasounds (HIFU) and monitoring the release profile of the drug at the tumor site thanks to Magnetic Resonance Imaging (MRI) imaging.

A new versatile thermosensitive liposome has been designed and developed to efficiently encapsulate a drug (doxorubicin) and a contrast agent (superparamagnetic iron oxide nanoparticles).

Summary

Photodynamic therapy in the elderly and heavily pretreated cancer patient populations may represent a promising therapeutical option in the management of malignant diseases provided that different approaches bring real improvement for its clinical application.

Silica-based nanocarrier encapsulating photosensitizers, the protoporphyrin IX (Pp IX), have been designed to improve the tumor bioavailability, to reduce photosensitizer accumulation in the skin and to differentially deliver the nanocarriers to cell organelles.

Pp IX silica-based nanocarriers were explored in in vitro and in vivo models with the ambition to improve knowledge on the role of biological factors in the photodamages. Some key features are presented here.

Summary

Nanotechnology offers revolutionary strategies to improve healthcare. Adequate nanomaterial characterization constitutes the basis to establish relevant programs of nanoparticle/biological systems cross talk evaluation. Also, the surrounding conditions significantly impact on the state of the nanoparticles in terms of their collective behavior: dispersion, aggregation, and stability in gas or liquid.

The “principle of designing” specific products is the paradigm of the nanomedecine. It is really new and it represents an essential point since creating innovative products should be supported by a previous risk evaluation based on the nanoscale chemistry. Furthermore, size does matter. Thus, both, size and chemistry of nanoparticles are probably the fundamental parameters from which all others depend on, and ultimately nanomaterial surface. And surfaces are the key players when considering safety.