Enhanced cellular uptake and nuclear accumulation of drug-peptide nanomedicines prepared by enzyme-instructed self-assembly.

Subcellular delivery of nanomedicines has emerged as a promising approach to enhance the therapeutic efficacy of anticancer drugs. Nuclear accumulation of anticancer drugs are essential for its therapeutic efficacy because their targets are generally located within the nucleus. However, strategies for the nuclear accumulation of nanomedicines with anticancer drugs rarely reported. In this study, we reported a promising nanomedicine, comprising a drug-peptide amphiphile, with enhanced cellular uptake and nuclear accumulation capability for cancer therapy. The drug-peptide amphiphile consisted of the peptide ligand PMI (TSFAEYWNLLSP), which was capable of activating the p53 gene by binding with the MDM2 and MDMX located in the cell nucleus. Peptide conformations could be finely tuned by using different strategies including heating-cooling and enzyme-instructed self-assembly (EISA) to trigger molecular self-assembly at different temperatures. Due to the different peptide conformations, the drug-peptide amphiphile self-assembled into nanomedicines with various properties, including stabilities, cellular uptake, and nuclear accumulation. The optimized nanomedicine formed by EISA strategy at a low temperature of 4 °C showed enhanced cellular uptake and nuclear accumulation capability, and thus exhibited superior anticancer ability both in vitro and in vivo. Overall, our study provides a useful strategy for finely tuning the properties and activities of peptide-based supramolecular nanomaterials, which may lead to optimized nanomedicines with enhanced performance.

ß-Galactosidase instructed supramolecular hydrogelation for selective identification and removal of senescent cells.

The identification and removal of senescent cells is very important to improve human health and prolong life. In this study, we introduced a novel strategy of ß-galactosidase (ß-Gal) instructed peptide self-assembly to selectively form nanofibers and hydrogels in senescent cells. We demonstrated that the in situ formed nanofibers could alleviate endothelial cell senescence by reducing p53, p21, and p16INK4a expression levels. We also demonstrated that our strategy could selectively remove senescent endothelial cells by inducing cell apoptosis, with an increase in the BAX/BCL-2 ratio and caspase-3 expression. Our study reports the first example of enzyme-instructed self-assembly (EISA) by a sugar hydrolase, which may lead to the development of supramolecular nanomaterials for the diagnosis and treatment of many diseases, such as cancer, and for other applications, such as wound healing and senescence.

Synthesis of butyl oleate catalyzed by cross-linked enzyme aggregates with magnetic nanoparticles in rotating magneto-micro-reactor.

In order to increase application of cross-linked enzyme aggregates (CLEAs) in industry production, a novel micro-reactor system that included a rotating magnetic field (RMF), a micro-reactor and CLEAs with magnetic nanoparticles (M-CLEAs) was designed to synthesize butyl oleate. Result showed that the presence of RMF significantly increased the yield of butyl oleate and the maximum increment was 23%. The yield of butyl oleate was impacted by the dosage and distribution of M-CLEAs in micro-reactor. M-CLEAs showed good reusability, since the morphology and the second structure of protein of M-CLEAs did not show evident change after 4 operative cycles. Although the three-dimensional fluorescence of M-CLEAs showed shift in fluorescence intensity and the maximum emission wavelengths, the yield of butyl oleate was not affected. This study provides a novel design that realized efficient, convenient and continuous application of CLEAs in biosynthesis, and M-CLEAs also show good promises in industry production.

Preparation, activity and structure of cross-linked enzyme aggregates (CLEAs) with nanoparticle.

Cross-linked enzyme aggregates (CLEAs) have emerged as an interesting biocatalyst design for enzyme immobilization. However, the commercialization of CLEAs is often hampered by their shortcomings, such as poor-controlled particle size, low activity and sticky characteristic. In order to overcome these drawbacks, five nanoparticles (NPs) (nano-TiO2, nano-MgO, nano-Ni, nano-Cu and nano-Fe3O4) were used to improve CLEAs activity and structure in this study. Results showed that moderate dosage of nano-TiO2 addition increased CLEAs activity, and the most increment was 15.2% relative to CLEAs without NPs. This was possibly due to more channels and smaller size particle of CLEAs after nano-TiO2 addition. Moreover, nano-TiO2 addition not only decreased fluorescence intensity but also caused the red shift in tryptophan (Trp) and tyrosine (Typ) residues. Nano-TiO2 addition decreased Km and increased Vmax of CLEAs. These changes were benefit to the activity and structure of CLEAs. However, addition of other four NPs (nano-MgO, nano-Ni, nano-Cu and nano-Fe3O4) did not increase CLEAs activity and even decrease CLEAs activity due to less amorphous cavities and larger or discrete particle size than CLEAs without NPs. In addition, FT-IR results showed that NPs addition increases the content of regular structure of CLEAs, and causes a partial transformation of ß-turn into ß-sheet. This study showed that it was potential to improve CLEAs performance by nano-TiO2 addition.