Gold nanorods for percutaneous drug delivery
Drug delivery: from needles to nanorods?
NanoNewsNet based on the materials of the Royal Society of Chemistry:
Drug delivery: from needles to nanorods?Japanese scientists have come to the conclusion that gold nanorods heated by near-infrared light can become an ideal means of transdermal drug delivery.
They found that even bulky protein molecules, often used in vaccines, can be introduced into the body in this way.
Transdermal drug delivery has many advantages over pills and injections, according to Dakrong Pissuwan, Takuro Niidome and their colleagues from Kyushu University. Drugs delivered in this way avoid the risk of too rapid destruction in the liver, and vaccines can induce a stronger immune response, since many antigen-recognizing cells of the immune system are present in the skin.
However, large hydrophilic proteins, as a rule, are poorly absorbed through the skin, as they are delayed by the stratum corneum – a hydrophobic barrier of dead cells that make up the outer surface of the skin. Pissuvan and Niidome showed how gold nanorods can help one of these proteins – egg albumin, or ovalbumin (OVA) – overcome this barrier and enter the body.
The researchers took advantage of the fact that gold nanorods heat up when irradiated with near–infrared light - a property known as the photothermal effect. By mixing OVA, nanorods and surfactant (surfactant), they obtained an oil-based dispersion that can be applied to the skin. When heated by near-infrared light, the nanorods destroy the stratum corneum, allowing the protein to pass through the skin and enter the body. Tests on mice have shown that with this method of administration, the protein causes an active reaction from the immune system.
"We believe that the immune response induced by such protein administration is sufficient for our method to be used for vaccination," comments Pissuvan on his development.
Preliminary tests on mice have not yet revealed any serious side effects. However, some details of the process still need to be clarified. In particular, researchers should check whether it causes skin damage.
"Before the start of clinical trials, the penetration through the skin of the gold nanorods themselves should be studied," explains the scientist.
Preparation of the surfactant-protein-gold nanorange complex
"If the method works on humans in the same way as on mice, it will be a good way to deliver proteins," says Tom Robertson, who is engaged in transdermal drug delivery at the University of South Australia (University of South Australia). "Its attractiveness to the patient is obvious – after all, he will not have any fear of the needle. If the method leads to stricter adherence to the vaccination program, it will make a big step forward."
The technological process will also be much cheaper than that of a competing method of administering vaccines – patches with microneedles – due to the peculiarities of their production.
With the help of heated gold nanorods, other types of drugs can be injected into the body, which are currently being selected by Pissuvan and Niidome.
Article by Dakrong Pissuwan et al. A Solid-in-Oil Dispersion of Gold Nanorods Can Enhance Transdermal Protein Delivery and Skin Vaccination is published in the journal Small.
Portal "Eternal youth" http://vechnayamolodost.ru20.12.2010