Delivering drugs with a femtosecond laser

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Researchers from the Okinawa Institute of Science (OIST) in Japan, in collaboration with the University of Otago in New Zealand have developed a technique that uses femtosecond lasers to deliver drugs. In the new method, described in June’s issue of Scientific Reports, the laser is used to release dopamine - the function of which is impaired in Parkinson ’s disease - in a controlled and repeatable manner.

Drugs are currently administered in a systemic way, meaning that the tissues and organs that do not need the drug also receive it, causing unwanted side effects. For example, chemotherapy is toxic to not only cancer cells, but also to healthy tissue; leading to side effects such as sickness and hair loss. 

Recent advances in nanotechnology and biology are opening up possibilities in targeted drug delivery, where researchers can release drugs or compounds in a specific tissue or even individual cells, which would allow the drug to reach only its intended target. In the technique developed at OIST, a drug is encapsulated inside of a shell of lipids, or fat (a liposome) to modulate the release of the drug using a laser pulse.

In Parkinson’s disease, the neurochemical dopamine does not function properly, so the researchers wanted to use the precise timing and intensity of femtosecond lasers to control the release of dopamine in a way that mimicked its natural dynamic mechanism.

Using the technique described, the researchers encapsulated dopamine in a liposome tethered to a gold nanoparticle. The energy from the femtosecond laser source is then absorbed by the gold nanoparticle and transferred to the liposome, causing the liposome to open and release the dopamine (see figure 1). The length of time and therefore amount of dopamine released can be precisely controlled by the intensity and length of time the laser is on. ‘With this method, we can administer a wide range of drugs with precise timing and duration using laser pulses with sub-second accuracy,’ said Takashi Nakano of the OIST Neurobiology Research Unit.


Figure 1: Dopamine is encaspulated into a liposome attached to a gold nanoparticle. The femtosecond laser is used as the energy source, which is absorbed by the gold nanoparticle. The energy from the gold nanoparticle is transferred to the liposome, causing it to open and release the dopamine. Credit: OIST

The researchers also showed that the liposomes are not destroyed by the laser, which was the case in previous similar studies.

The next step is to use the laser-activated liposomes in living tissue, and eventually, in a live animal. If the technique is proven in humans, it will create the ability to release potentially any type of drug, chemical or naturally occurring compound in the right place at the right time with a controlled dosage, which will open many new possibilities in medicine.