On-Demand Elongation of Peptide Nanofibrils at Cellular Interfaces to Modulate Cell-Cell Interactions.

Natural cells can achieve specific cell-cell interactions by enriching nonspecific binding molecules on demand at intercellular contact faces, a pathway currently beyond synthetic capabilities. We are inspired to construct responsive peptide fibrils on cell surfaces, which elongate upon encountering target cells while maintaining a short length when contacting competing cells, as directed by a strand-displacement reaction arranged on target cell surfaces. With the display of ligands that bind to both target and competing cells, the contact-induced, region-selective fibril elongation selectively promotes host-target cell interactions via the accumulation of nonspecific ligands between matched cells. This approach is effective in guiding natural killer cells, the broad-spectrum effector lymphocytes, to eliminate specific cancer cells. In contrast to conventional methods relying on target cell-specific binding molecules for the desired cellular interactions, this dynamic scaffold-based approach would broaden the scope of cell combinations for manipulation and enhance the adjustability of cell behaviors for future applications.

Multiple Stimulus Response Material Based on Sr-tcbpe MOF for Mechanochromism, Visualization Labeling, and Etching Toward TNP.

The abuse and excessive discharge of organic pollutants such as nitroaromatic compounds (NACs) have become a hot topic of concern for all humanity and society, and the development of fast, effective, and targeted technical means for detecting NACs also faces many challenges. Here, we reported a strontium-based metal-organic framework (MOF) {[Sr2(tcbpe)(H2O)4]}n (Sr-tcbpe), in which tcbpe represents deprotonated 4',4‴,4″‴,4‴‴-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1'biphenyl]-4-carboxylic acid)). In Sr-tcbpe, Sr-O polyhedron and deprotonated tcbpe4- ligand have a staggered connection to form a self-assembled three-dimensional network structure. In addition, it is found that Sr-tcbpe undergoes no luminescent color change when grinding under solvent protection, while mechanochromic fluorescence behavior is observed when grinding directly, leading to luminescent color changes from cyan to green (Sr-tcbpe-G). Additionally, Sr-tcbpe and Sr-tcbpe-G could selectively detect PNP, DNP, and TNP, and Sr-tcbpe achieves visual fluorescence sensing detection toward TNP at a limit of detection as low as 2.25 µM. Moreover, during the detection process, unexpectedly, TNP exhibits a selective etching effect on Sr-tcbpe, which could drill nano holes with different sizes on the surface area of MOF materials to a certain extent, achieving the conversion of chemical energy to mechanical energy. In addition, the successful preparation of a portable sensor Sr-tcbpe@gypsum block provides a platform for the perfect combination of mechanochromic fluorescence behavior and visualization detection toward TNP. It lays the foundation for the practical application of MOF materials in daily life.

Preparation, characterization and application of CS@PDA@Fe3O4 nanocomposite as a new magnetic nano-adsorber for the removal of metals and dyes in wastewater.

This study aimed to develop a novel magnetic chitosan/dopamine/Fe3O4 nano-adsorber (CS@PDA@Fe3O4) for the removal of heavy metal ions and organic dye molecules from aqueous solution. CS@PDA@Fe3O4 was prepared by surface modification of PDA/Fe3O4 nanoparticles with chitosan using IPTES as the cross-linker. The surface structure, composition, and properties of the CS@PDA@Fe3O4 nano-adsorber were characterized by elemental (EDS), spectroscopic (XRD, XPS, and FT-IR), magnetic intensity (VSM), surface and morphological (TEM and SEM) analyses. In order to study its adsorption behavior, equilibrium and kinetics studies were carried out through batch experiments. Additionally, the influences of the pH value, initial concentration, adsorbent dose, and contact time were also evaluated. The CS@PDA@Fe3O4 nano-adsorber exhibited high adsorption capacity especially for Cu(ii), with a maximum adsorption capacity of 419.6 mg g-1. The experimental data were well described by the Langmuir isotherm kinetic models.

Characterization and evolution of xylose isomerase screened from the bovine rumen metagenome in Saccharomyces cerevisiae.

The conversion of abundant levels of xylose in lignocellulosic materials into viable products would generate economic benefits. The heterologous expression of the xylose isomerase (XI) gene is considered a direct and effective strategy for establishing the xylose metabolic pathway in Saccharomyces cerevisiae. However, only limited sources of xylA are functionally expressed in S. cerevisiae and are capable of driving effective xylose consumption. In this study, Ru-xylA (where Ru represents the rumen), which was screened from the contents of the bovine rumen metagenomic library, was functionally expressed in S. cerevisiae, and the enzyme activity was 1.31 U mg(-1) protein. This is a new source of XI that can exhibit high activity levels in S. cerevisiae. The activity of this enzyme is comparable to those of the Piromyces sp. XI. Then, the Ru-XI activity was further improved through mutagenesis and growth-based screening in a centromeric plasmid. A variant containing two mutations (K11T/D220V) that exhibited a 68% increase in enzyme activity was isolated. Our work identified a new xylose isomerase that can be functionally expressed in S. cerevisiae and results in a higher XI enzyme activity through mutagenesis.