Hanieh Askari,1Saman Hakimian,2,*
1. Biotechnology student , Kashan University 2. M.sc student of Microbiology Islamic Azad University Central Tehran Branch, Iran, Tehran
Introduction: Cancer treatment is one of the major challenges of modern medicine.
Traditional cancer therapies that include chemotherapy, radiation therapy, targeted therapy and immunotherapy, import lots of toxicity problems to patients, because they are not selective to tumor cells.
Nanotechnology has been extensively studied and exploited for cancer treatment as nanoparticles can play a significant role as a drug delivery system.
Nanoparticle (NP)-based drug delivery systems have shown many advantages in cancer treatment, such as good pharmacokinetics, precise targeting of tumor cells, reduction of side effects, and drug resistance.
The NPs used in medical treatment usually have specific sizes, shapes, and surface characteristics as these three aspects have a major influence on the efficiency of the nano-drug delivery and thus control therapeutic efficacy.
NPs with a diameter range of 10 to 100 nm are generally considered suitable for cancer therapy, as they can effectively deliver drugs and achieve enhanced permeability and retention (EPR) effect. Smaller particles can easily leak from the normal vasculature (less than 1–2 nm) to damage normal cells and can be easily filtered by kidneys (less than 10 nm in diameter, while particles that are larger than 100 nm are likely to be cleared from circulation by phagocytes.
Methods: Active targeting specifically targets cancer cells through direct interactions between ligands and receptors. The ligands on the surface of NPs are selected to target the molecules that are overexpressed on the surface of cancer cells, which allows them to distinguish targeted cells from healthy cells. The interaction between ligands on NPs and the receptors on the surface of cancer cells induces receptor-mediated endocytosis, which allows internalized NPs to successfully release therapeutic drugs. Therefore, active targeting is particularly suitable for macromolecular drug delivery, such as proteins and siRNAs.
Results: Moreover, the surface characteristics of NPs can influence their bioavailability and half-life. For instance, NPs that are coated with hydrophilic materials such as polyethylene glycol (PEG) lessen the opsonization and therefore avoid clearance by the immune system. Therefore, NPs are generally modified to become hydrophilic, which increases the time period of drugs in circulation and enhances their penetration and accumulation in tumors.
Conclusion: Targeting of cancer cells specifically is a vital characteristic of nano-carriers for drug delivery, as it enhances the therapeutic efficacy while protecting normal cells from cytotoxicity.
The targeting mechanisms can be broadly divided into two categories, passive targeting and active targeting.
Keywords: cancer, nanoparticle, treatment, targeting, active