Although biological systems can self-assemble increasingly complex structures from simple building blocks with high precision, attempts to mimic this process to synthesize self-assembling nanodevices for drug delivery can often yield products with limited functionality.
A team of researchers, led by Klaus-Viktor Peinemann from King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, managed to synthesize complex microsphere particles from block copolymers by self-assembly, publishing their findings in Nature Communications.1
By using electron microscopy, the team found the microspheres have ordered nanometre-sized pores uniformly distributed across their surface and inside the particles, which act as pH-sensitive gates. The charged nature of these microspheres and the abundance of the nanopores make it an optimal carrier for polar drugs, such as proteins, allowing many drug molecules to be loaded in each particle. Once it reaches a specific pH environment, the drug is repelled from the particle and released at a controlled rate over an extended period of time.
“We will refine the pore gating mechanism and find other door-openers,” says Peinemann. “For example, it would be quite attractive if glucose would open the pores and trigger the release of adsorbed insulin.”
Additionally, the particles can be used to separate proteins of similar size with high selectivity, something conventional methods fail to achieve, if the proteins have different overall charges at the same pH environment.
Yu, H., Qiu, X., Nunes, S. P. & Peinemann, K.-V. Biomimetic block copolymer particles with gated nanopores and ultrahigh protein sorption capacity. Nature Commun. 5, 4110 (2014).