Image: SCPNs triggering fluorescence locally (in green) by activating a pro-fluorophore molecule.
SCPNs are nanometer-sized objects inspired in the way enzymes work; they carry a catalyst which is activated when the structure is folded. Although artificial enzymes had been reported before, this study is the first to demonstrate their viability in complex environments such as the cell. “Shielding in SCPNs is a non-toxic, biocompatible way of containing a synthetic catalyser working in harmony with what’s already going on in the cell,” says Silvia Pujals, a postdoc in Lorenzo Albertazzi’s group at IBEC. “In other words, it doesn’t interfere with the normal behaviour of cells.”
The SCPNs under study can be delivered intracellularly or extracellularly depending on the envisioned application. For photodynamic therapy (PDT) applications an intracellular delivery is needed while organometallic catalysts work well extracellularly. This last application of SCPNs is for controlled drug delivery. For example, the synthetic enzymes could activate anti-tumour drugs delivered through the blood stream just at the tumour area. “So far, we have obtained promising results by locally activating a fluorophore with the SCPNs as catalysts just at the SCPN exposed areas,” says Lorenzo. “We believe that these enzyme-like nanoparticles could be used for their pro-drug activity in different biomedical applications.”
Source article: Yiliu Liu, Silvia Pujals, Patrick J.M. Stals, Thomas Pauloehrl, Stanislav I. Presolski, E. W. Meijer, Lorenzo Albertazzi, and Anja R.A. Palmans (2018). Catalytically Active Single-Chain Polymeric Nanoparticles: Exploring Their Functions in Complex Biological Media. J. Am. Chem. Soc., 140(9):3423-3433