Theranostics: a new step
A new system for nanoteranostics has been created
Scientists from the Federal Polytechnic School of Lausanne (EPFL) and the University of Geneva (Switzerland) have developed a new nanoteranostic system that uses "harmonic nanoparticles" – a family of metal oxide nanocrystals with unique optical properties: they react to excitation not only from ultraviolet, but also from infrared light, which is much safer for the patient.
Article by Vuilleumier et al. Two-photon triggered photorelease of caged compounds from multifunctional harmonic nanoparticles is published in the journal ACS Appl. Mater. Interfaces.
Theranostics is a developing field of medicine, the name of which contains the words "therapy" and "diagnostics". The idea of theranostics is to create drugs and treatment methods that are simultaneously used for early diagnosis of the disease, for treatment, and for monitoring the patient's reaction. This saves time and money and can circumvent some undesirable biological effects that can occur when these strategies are used separately.
Today, nanoparticles are increasingly used in theranostics, which combine diagnostic molecules and drugs into a single agent. Nanoparticles act as carriers for molecular "cargo" – for example, drugs or radioisotopes for cancer patients undergoing radiation therapy. This "transport" is directed to specific biological pathways in the patient's body and can avoid damage to healthy tissues at the same time.
Once in the target tissue, the nanoparticles either help to make diagnostic images, or deliver their cargo (or both). Specialists control them with the help of light. This is an advanced technology of "nanoteranostics", which has become the main focus of research. Although it has numerous limitations, there are disadvantages that need to be overcome.
"Most light–activated nanoteranostic systems need high-energy ultraviolet light to excite their photoreactive scaffolds," says Sandrine Gerber from EPFL. "The problem is that this leads to poor penetration depth and can damage living cells and tissues, which limits biomedical applications."
The new system developed by the Gerber group avoids these problems by using bismuth-ferrite "harmonic nanoparticles" based on silicon oxide, which carry photosensitive molecular "loads". These systems can be easily activated using near-infrared light (wavelength 790 nanometers) and mapped to a longer wavelength for drug detection and isolation processes. Both of these features make the system safe for patients.
Figure from the EPFL press release On the way to nanotheranostics – VM.
After the light is triggered, the nanoparticles release their cargo – in this case, L-tryptophan, which the researchers used as a model. Scientists monitored and quantified the release of the "cargo" using liquid chromatography and mass spectrometry.
The authors claim that "this work is an important step in the development of nanoparticle platforms that allow images to be separated by tissue depth and therapeutic drugs to be produced on demand."
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