Simultaneous Removal of Antibiotics and Heavy Metals with Poly(Aspartic Acid)-Based Fenton Micromotors

The discharge of diverse pollutants has led to a complex water environment and posed a huge health threat to humans and animals. Self-propelled micromotors have recently attracted considerable attention for efficient water remediation due to their strong localized mass transfer effect. However, a single functionalized component is difficult to tackle with multiple contaminants and requires to combine different decontamination effects together. Here, we introduced a multifunctional micromotor to implement the adsorption and degradation roles simultaneously by integrating the poly(aspartic acid) (PASP) adsorbent with a MnO₂-based catalyst. The as-prepared micromotors are well propelled in contaminated waters by MnO₂ catalyzing hydrogen peroxide. In addition, the catalytic ramsdellite MnO₂(R-MnO₂) inner layer is decorated with Fe₂O₃ nanoparticles to improve their catalytic performance, contributing to an excellent degradation ability with 90% tetracycline (TC) removal in 50 minutes by enhanced Fenton-like reactions. Combining the attractive adsorption capability of poly (aspartic acid) (PASP), the composite micromotors offer an efficient removal of heavy metal ions in short time. Moreover, the designed micromotors are able to simultaneously remove antibiotic and heavy metals in mixed contaminants circumstance just in single treatment. This multifunctional micromotor with distinctive decontamination ability exhibits a promising prospective in treating multiple pollutants in the future.     

Photo-Controlled Macroscopic Self-Assembly Based on Photo-Switchable Hetero-Complementary Quadruple Hydrogen Bonds

A photo-switchable hetero-complementary quadruple H-bonding array, which consists of an azobenzene-derived ureidopyrimidinone (UPy) module ( Azo-UPy ) and a nonphotoactive diamidonaphthyridine (DAN) derivative ( Napy-1 ), is constructed based on a reversible photo-locking approach. Upon UV (390 nm)/Vis (460 nm) light irradiations, photo-switchable quadruple H-bonded dimerization between Azo-UPy and Napy-1 can be achieved with exhibiting 4.8×10⁴-fold differences in binding strength (ON/OFF ratios). Furthermore, smart polymeric gels with unique photo-controlled macroscopic self-assembly behavior can be fabricated by introducing such quadruple H-bonding array as photo-regulable noncovalent interfacial connections.     

Light-fueled dissipative self-assembly at molecular and macro-scale enabled by a visible-light-responsive transient hetero-complementary quadruple hydrogen bond

The development of out-of-equilibrium self-assembly systems using light as input fuel is highly desirable and promising for the fabrication of smart supramolecular materials. Herein, we report the construction of new artificial light-fueled dissipative molecular and macroscopic self-assembly systems based on a visible-light-responsive transient quadruple H-bonding array, which consists of an azobenzene-modified ureidopyrimidinone (UPy) module (Azo-O-UPy) and a nonphotoactive diamidonaphthyridine (DAN) derived competitive binder (Napy-1). The visible light (410 nm) irradiation can induce the E to Z isomerization of the azobenzene unit of E-Azo-O-UPy to produce Z-Azo-O-UPy with an opened UPy binding site, which can complex with Napy-1 to form a quadruply H-bonded heterodimer. The heterodimer is metastable and can be quickly disassembled in dark, owing to the fast thermal relaxation of Z-Azo-O-UPy to E-Azo-O-UPy. While introducing such transient quadruple H-bonding interaction into a linear polymer system or a polymeric gel system, light-fueled out-of-equilibrium polymeric assembly both at molecular and macro-scale can be achieved.     

Transition metal phosphides: A wonder catalyst for electrocatalytic hydrogen production

Hydrogen evolution from water electrolysis has become an important reaction for the green energy revolution. Traditional precious metals and their compounds are excellent catalysts for producing hydrogen; however, their high cost limits their large-scale practical application. Therefore, the development of affordable electrocatalysts to replace these precious metals is important. Transition metal phosphides(TMPs) have shown remarkable performance for hydrogen evolution and garnered considerable ...     

Cooperative coupling of photocatalytic production of H2O2 and oxidation of organic pollutants over gadolinium ion doped WO3 nanocomposite

This work reported the lanthanide ion (Gd³⁺) doped tungsten trioxide (Gd-WO₃) nanocrystal for remarkable promoted photocatalytic degradation of organic pollutants and simultaneous in-situ H₂O₂ production. With doped lanthanide ion (Gd³⁺), Gd-WO₃ showed a much broad and enhanced solar light absorption, which not only promoted the photocatalytic degradation efficiency of organic compounds, but also provided a suitable bandgap for direct reduction of oxygen to H₂O₂. Additionally, the isolated Gd³⁺ on WO₃ surface can efficiently weaken the *OOH binding energy, increasing the activity and selectivity of direct reduction of oxygen to H₂O₂, with a rate of 0.58 mmol L⁻¹ g⁻¹ h⁻¹. The in-situ generated H₂O₂ can be subsequently converted to ^•OH based on Fenton reaction, further contributed to the overall removal of organic pollutants. Our results demonstrate a cascade photocatalytic oxidation-Fenton reaction which can efficiently utilize photo-generated electrons and holes for organic pollutants treatment.     

TBAI/H2O-cooperative electrocatalytic decarboxylation coupling-annulation of quinoxalin-2(1H)-ones with N-arylglycines

The first example of TBAI/H₂O cooperative electrocatalytic coupling-annulation of quinoxalin-2(1H)-ones with N-arylglycines was developed. A broad range of tetrahydroimidazo[1,5-a]quinoxalin-4(5H)-ones were obtained in good to excellent yields with exclusive chemoselectivities and excellent regioselectivities. The H-hydrogen bond served as a key factor for the electrocatalytic production of aminomethyl radical at lower oxidative potential.     

Rare-earth ions coordination enhanced ratiometric fluorescent sensing platform for quantitative visual analysis of antibiotic residues in real samples

Levofloxacin (LVFX) as a representative drug of quinolone antibiotics is widely used in clinical, and its residues enriched in water bodies and sideline products seriously damage human health. It is imperative to develop a real-time/on-site sensing method for monitoring residual antibiotics. Here, we report a portable sensing platform by utilizing a composite fluorescent nanoprobe constructed by the cerium ions (Ce³⁺) coordination functionalized CdTe quantum dots (QDs) for the visual and quantitative detection of LVFX residues. This fluorescent probe provides a distinct color variation from red to green, which shows a good linear relationship to LVFX residues concentrations in the range of 0-6.0 µmol/L with a sensitive limit of detection (LOD) of 16.3 nmol/L. The smartphone platform with Color Analyzer App installed, which could accomplish quantified detection of LVFX in water, milk, and raw pork with a LOD of 27.9 nmol/L. The facile sensing method we proposed realizes rapid visualization of antibiotics residual in the environment and provides a practical application pathway in food safety and human health.     

3D microgel with extensively adjustable stiffness and homogeneous microstructure for metastasis analysis of solid tumor

3D microgels with various mechanical properties have been important platforms tumor metastasis analysis, and widely adjustable stiffness is crucial for deeper researches. Herein, by mixing biodegradable polylactic acid (PLA) nanofibers in the modified alginate with different concentrations of Ca²⁺, we significantly enhance the stiffness range of microgels while retaining the pore size, which provides bionic microenvironment for tumor analysis. As a proof of concept, we simulated the mechanical characteristics of breast tumors by encapsulating cells in 3D microgels with diverse stiffness, and analyzed cellular behaviors of two typical breast cancer cell lines: MCF-7 and SUM-159. Results showed that with the addition of 2.0% (w/v) PLA short nanofibers, the Young's modulus of modified alginate increased more than three-fold. Besides preserving high survival and proliferation rates, both cells also displayed stronger migration ability in soft microgel spheres, where RT-qPCR analysis revealed the underlying changes at the genetic level. This systematic study demonstrated our method is powerful for creating widely adjustable 3D mechanical microenvironment, and the results of cellular behavior analysis shows its promising application prospects in tumorigenesis and progression.     

Synergistic Pd/Cu-catalyzed regio- and stereoselective cascade Heck cyclization/borylation/cross-coupling

A cooperative Pd/Cu-catalyzed three-component cross-coupling reaction of alkynes, B₂Pin₂ and alkene-tethered aryl halides is reported. This reaction proceeds under mild conditions and shows broad substrate scope, providing a variety of heterocycles containing tetrasubstituted alkenylboronate moieties in synthetically useful yields with excellent chemoselectivity and regioselectivity. This transformation features the catalytic generation of β-borylalkenylcopper intermediates and their use in Pd-catalyzed Heck cyclization/cross-couplings. An enantioselective cascade cyclization/cross-coupling process has also been developed for the synthesis of enantiomerically enriched oxindole bearing a tetrasubstituted alkenylboronate moiety.     

Basics of optical force

Light possesses momentum, and hence, force is exerted on materials if they absorb and/or scatter light. Laser techniques that use optical forces are currently attracting considerable attention. Optical manipulation for trapping, transporting small particles, and measuring the interparticle force is a representative technique. In addition, photoinduced force microscopy is a promising scanning type of microscopy using optical force. Optical force techniques have recently been used in various fields of research, such as molecular bioscience, organic photochemistry, materials engineering, and molecular fluid dynamics. In these techniques, several types of optical forces such as scattering, absorption, and gradient forces play their respective roles. In this article, we summarize the basics of optical forces and present their elementary expressions for using simplified models of light and matter systems. This will help the readers of this Special Issue to understand how different types of forces are distinguished in the basic expressions used for analyzing the optical force phenomena that appear depending on the light geometry and matter systems. After observing simplified cases of scattering and absorption forces, we introduce general formulae for the optical force and then discuss how different components appear in particular cases of laser geometry and materials.