New technique to make drugs 'smarter' developed

Scientists have developed a new method to make 'smarter' drugs that are more effective at reaching their target.

The researchers from the University of Lincoln in the UK devised a technique to 'decorate' gold nanoparticles with a protein of choice so they can be used to tailor drug to more accurately target an area on the body, such as a cancer tumour.

"Gold nanoparticles are a vital tool in new drug development and drug delivery systems. We have unlocked the key to binding proteins and molecules so that those drugs will be more effective," said Enrico Ferrari, a nanobiotechnologist from the University of Lincoln.

"This method might help to design nanomedicines that do not need extensive chemical modification of a protein drug or a nano-carrier and therefore can be developed more easily and faster," said Ferrari, who led the study published in the journal Nature Communications.

Researchers took fragments of proteins from bacteria and flatworms, which when fused together were effective at binding to the gold nanoparticle surface and able to form stable bonds to any other protein.

By mixing this fusion protein with gold nanoparticles, it permanently binds to the gold surface while also being able to stably bind a target protein on which a specific 'tag' was included.

Gold nanoparticles are spheres made of gold atoms with a diameter of only few billionths of a metre which can be coated with a biological protein and combined with drugs to enable the treatment to travel through the body and reach the affected area.

The nanoparticles can 'adsorb' (hold on its surface) drugs which would otherwise become insoluble or quickly degrade in the blood stream.

Due to their small size they can overcome biological barriers such as membranes, skin and the small intestine which would usually prevent the drug from reaching its target.

The technology is already used in real world applications such as pregnancy tests - where gold nanoparticles decorated with an antibody against the hormone present in the urine of pregnant women is added to the 'positive' strip so it reacts with the nanoparticles to turn the stick red.

Until now the process of coating the nanoparticles meant that the proteins used had to be 'mixed' together with particles which do not have the ability to control the way they bind, possibly making the drug less effective.

The new method enables pharmacologists to place the proteins onto the gold nanoparticles layer by layer in a specific order.

This maintains the integrity of the protein so that the drug is more effective, opening up possibilities for the development of nanomedicine.