NEWS: Formulating dual-function nanoparticles for photodynamic and photothermal cancer therapy
http://nanotechweb.org/cws/article/lab/48277
Jan 12, 2012
Formulating dual-function nanoparticles for photodynamic and photothermal cancer therapy
Light-based techniques such as photodynamic therapy (PDT) and photothermal therapy (PTT) may offer promising opportunities for cancer treatment. This has prompted the design of novel nanoparticles with dual functions.
Morphological changes induced by exposure and laser treatment
PDT involves the localization of photosensitizers in target tissue. Upon irradiation with light of an appropriate wavelength (usually visible light), a complex photochemical reaction is initiated to generate reactive oxygen species and trigger a cascade of molecular events that lead to cell death. PTT is an experimental use of electromagnetic radiation (most often in the form of infrared light) to generate significant local hyperthermia for the destruction of cells or tissues. Unlike photodynamic therapy, photothermal therapy does not require oxygen to interact with the target cells or tissues.
Phycocyanin (PC) is a photoharvesting pigment that provides the intense blue colour in blue-green algae. The water-soluble protein is frequently used as a colouring agent in food and cosmetics. Most importantly, PC is also a cytotoxic photosensitizer capable of killing cells via singlet oxygen production upon visible light radiation. As a result, PC could be an attractive candidate for PDT due to its solubility, non-carcinogenicity and non-toxicity.
Carbon nanotubes (CNTs) have been considered potential biomedical materials because of their interesting physicochemical properties, such as high surface area, high electrical and thermal conductivity. Compared with single-walled carbon nanotubes (SWNTs), multi-walled carbon nanotubes (MWNTs) can be expected to absorb significantly more near-infrared (NIR) radiation. MWNTs hold a particular interest for the development of PTT.
Conjugation strategy
CNTs tend to form bundles that disperse poorly in aqueous solutions, which would be unsuitable for pharmacological use. The inclusion of water-soluble chitosan (CS) on the one hand improves the water solubility of MWNTs, and on the other hand links MWNTs (the PTT agent) and PC (the PDT agent) together. CS possesses attractive characteristics. The material is non-toxic, easy to modify and low cost.
In their study, the researchers from South China University of Technology prepared and characterized nanoparticles comprising MWNT-CS-PC. The team tested the formulation on two human cancer cells (breast cancer cell line MCF-7 and liver cancer cell line HepG2) and one human normal cell (liver cell line L-o2) with and without laser irradiation.
The results showed that photoinduced cytotoxicity was indeed enhanced with irradiation of either NIR light (808 nm) or visible light (532 nm), suggesting that MWNT-CS-PC may potentially serve a biomedical material for future photodynamic and photothermal cancer therapy.
More information can be found in the journal Nanotechnology.
About the author
Xiaoxia Liao is an MSc student at the College of Light Industry and Food Science, South China University of Technology, Guangzhou, China, under the supervision of Prof. Dr Xuewu Zhang. Currently, the research interests of Prof. Zhang focus on the applications of nanotechnology to biomedicine and food science.
This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. E-mail transmission cannot be guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses. The sender therefore does not accept liability for any errors or omissions in the contents of this message, which arise as a result of e-mail transmission.
<< Home