Gold nanoparticles (AuNPs) present the many advantages of displaying relative biocompatibility, high light absorption and strong optical scattering properties. They are therefore good candidates to be used as probes for cancer imaging. By conjugating them with antibodies, these particles can be turned into targeted drugs. The construct would then selectively bind to the antigens overexpressed on tumour cells, and therefore be capable of locating tumours specifically.
Exploiting this concept, scientists at the Fraunhofer Institute for Biomedical Engineering IBMT have developed a new integrated biosensor system under the European Commission-funded project ADONIS. The name of this research consortium stands for Accurate Diagnosis of prostate cancer using Optoacoustic detection of biologically functionalized gold Nanoparticles.
To test their approach, they focused on a type of cancer that is most common among men, prostate cancer, in the hope that it will improve diagnostics substantially.
The treatment relies on optoacoustic imaging of gold nanoparticles. When light is absorbed by the AuNPs, pressure waves are generated. These waves travel through the patients’ tissue and can be analysed with techniques comparable to ultrasonic imaging. Conjugating AuNPs with an antibody makes the construct capable of binding to a tumour specific antigen. This approach could thus lead to the development of a new cancer diagnostics method.
By contrast, other teams in the US and the Czech Republic have also used gold nanoparticles. For example, some have used polyelectrolyte coating onto AuNPs as a means to put a charge on their surface and therefore increase the chances of these nanoparticles of being absorbed by cancer cells. Scientists then used X-ray scatter imaging to separate the AuNP-containing tumours from healthy tissue. This technique could go as far as detecting tumours only a few millimetres wide in the liver, which is not possible with currently used approaches.
Before gold nanoparticles change the way diagnostics is conducted, this method has yet to be tested in clinical trials.