Cancer today is one of the leading causes of death. Though highly developed technologies for treatment prevail, this disease still remains a deadly one, claiming many lives. The failure of chemotherapy for treating cancer can be attributed to: 1. Low aqueous solubility of anti-cancer drugs. 2. Low permeability. This leads to poor accessibility of anti-neoplastic agents to the tumor. High doses are required which result in toxicity and heavy side-effects.
This led to a need to improve the drug delivery and bio-availability.
Knowledge from nanotechnology, advanced polymer chemistry and electronic engineering is now employed to design new targeted drug delivery systems which ensure maximum drug concentration at the tumor site, preventing damage to normal tissues and controlled delivery of the chemotherapeutic agents.
Cancer treatment using nanotechnology utilizes the phenomenon of targeted bioconjugate drug delivery system; wherein a biocompatible and biodegradable polymer nanoparticle encapsulates the anti-cancer drug and binds to an aptamer.
The aptamers are small DNA or RNA fragments which bind to target antigens with high specificity and high affinity: analogous to Monoclonal Antibodies. They have the potential to act as targeting molecules-directing the encapsulated nanoparticles to the tumor-antigens present on the surface of tumor cells.
Eg: In case of prostrate cancer, the RNA-aptamers are highly specific to PSMA [prostrate specific membrane antigen], and bind to it. The PSMA is a marker for prostrate cancer, over-expressed on prostrate epithelial cells.
Thus, the highly specific RNA-aptamer along with the therapeutic nanoparticles is a specially designed delivery system that allows a pre-determined and regulated release of drug at the tumor site.
Once bound to the cancer cells, the nanoparticle-aptamer bioconjugates are internalized making it possible for their cytotoxic payload to get released directly inside the cancer cells.