Self-Assembling Peptide Artificial Enzyme as an Efficient Detection Prober and Inhibitor for Cancer Cells.

A new hybrid nanoparticle (NP; fluorenylmethoxycarbonyl-arginine-glycine-aspartate and hemin, Fmoc-RGD/hemin NP) was developed for the simultaneous detection and inhibition of breast cancer cells. Hemin can regulate the reactive oxygen species (ROS), while Fmoc-RGD acts as a scaffold for hemin nanocrystallization. Fmoc groups interact with the porphyrin groups of hemin through hydrophobic and π-π interactions to form a hydrophobic core of the NPs. The hydrophilic RGD chains surround the core to maintain the stability of the nanoparticles in an aqueous medium. The RGD groups of Fmoc-RGD are also selective for tumor cells. This interaction can be exploited to enhance the selectivity of tumor detection. Based on enhanced peroxidase activity, Fmoc-RGD/hemin NPs were developed as signal transducers in a facile and fast point-of-care cancer diagnosis platform. This platform is sensitive to breast cancer cells and hydrogen peroxide (H 2 O 2 ), a biomarker for breast cancer. In addition, these Fmoc-RGD/hemin NPs can be used as nanoscavengers for ROS and for regulating the redox status of cancer cells. They also exhibit a targeted inhibitory effect on the epithelial-mesenchymal transition (EMT). The peptide-tuned self-assembly of Fmoc-RGD/hemin NPs as functional artificial enzymes boasts simple preparation, biofriendliness, and the versatility required for on-demand therapeutics and diagnostics for metastatic cancer cells. These NPs can therefore be used as effective tools for potential applications in medicine and biotechnology.