Liposome factories produce higher quality uniform nanoparticles

Liposome factories produce higher quality uniform nanoparticles

New method could support drug delivery and biological probes

A new method that turns liposomes into tiny nanoparticle factories supports the step towards using gold nanoparticles in biological probes and drug delivery. The method, described in a new article in the Journal of Colloid and Interface Science, results in nanoparticles of a uniform size and shape, something the researchers were surprised to see.

“We were really surprised we could form such small and homogeneous nanoparticles,” said Dr. Sushanth Gudlur, lead author of the study from Linköping University in Sweden. “We thought since the liposomes were so small, we expected the nanoparticles to be smaller than when synthesized in a more conventional way, but surprised they were all so similar in size. We also did not anticipate that the nanoparticles would be so much smaller when prepared inside liposomes compared to regular bulk synthesis.”

Gold nanoparticles can be used in many areas, including biosensors, electronics, imaging and drug delivery. There are several ways to produce gold nanoparticles and liposomes – tiny bubbles with a thin membrane of lipids – turned out to be reaction vessels well suited to producing gold nanoparticles. One advantage is that they are already confined within liposomes, which can be used as biological probes and in drug delivery.

Researchers have attempted to synthesize gold nanoparticles in liposomes before, but the results have been inconsistent, with random-sized nanoparticles or a poor yield. Traditionally, researchers have made the gold nanoparticles first and then packaged them inside the liposomes for delivery.

In the new study, Dr. Gudlur, Dr. Daniel Aili and colleagues turned the ‘stairs’ between the first two steps – synthesis and packaging – into an ‘escalator’, simplifying the process and making it more convenient. They synthesized the gold nanoparticles inside the liposomes, taking away the need to package them after synthesis. Abs because the space is so confined, the nanoparticles produced were small and uniform. The gold nanoparticles were synthesized inside palmitoyl oleoyl phosphocholine (POPC) liposomes, and had an average size of 2.8 ± 1.6 nm.

“We were able to synthesize better quality gold nanoparticles without having to modify existing liposome preparation techniques and without the need for additional stabilizing agents,” said Dr. Gudlur.

“This is just the beginning and there’s still a lot of work to be done. Our work was done in tubes in the lab and the end application is inside the human body – it’s a completely different ballgame. We need to check for the stability of these liposomes and the nanoparticles, worry about the circulation time, toxicity, targeting and uptake by cells – a lot of things. But it’s an exciting time, and the technology has huge potential.”

Access the paper for free until 31 December 2015.