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Fabricating antibacterial hydrogels with antimicrobial drugs and synthetic biocompatible biomimetic hydrogels is a promising strategy for practical medical applications. Here, we report a bicomponent hydrogel composed of a biomimetic polyisocyanopetide (PIC) hydrogel and a photodynamic antibacterial membrane-intercalating conjugated oligoelectrolyte (COE). The aggregation behavior and aggregate size of the COEs in water can be regulated using the PIC hydrogel, which could induce COEs with higher reactive oxygen species (ROS) production efficiency and increased association of COEs toward bacteria, therefore enhancing the antibacterial efficiency. This strategy provides a facile method for developing biomimetic hydrogels with high antibacterial capability.

Utilizing solar energy for hydrogen production by combining light-activated materials and biocatalysts has become a promising alternative to fossil fuels. Herein, a feasible and simple bio-hybrid complex based on water-soluble oligofluorene (OF), polythiophene (PTP) and Rhodopseudomonas palustris (R. palustris), one kind of photosynthetic bacteria, was constructed for enhancing photocatalytic hydrogen production. Under the irradiation of visible light, there was fluorescence resonance energy transfer (FRET) between OF and PTP, which amplified photoelectron signals and transferred electrons via PTP to methyl viologen (MV2+), an electron mediator that established electron transfer pathways between organic materials and R. palustris. Hydrogen production involving R. palustris was catalyzed by nitrogenase. It is noteworthy that MV2+ was reduced to MV+˙ and transferred electrons to nitrogenase in R. palustris, converting protons and electrons to molecular hydrogen. Besides, triethanolamine (TEOA) was added as an electron donor to provide electrons to PTP. The proposed OF/PTP/MV2+/TEOA/R. palustris system provided a feasible strategy for photocatalytic hydrogen production with low-cost and easily implemented techniques.

A new concept named “rotating magnetocaloric effect (RMCE)” has been proposed and attracted more attention recently. Unlike the traditional MCE that is achieved by moving the magnetic refrigerant in and out of magnetic field, RMCE can be realized by rotating the anisotropic material within the static field, thus implying the possible higher efficiency and simpler device. However, most studies on RMCE are concentrated on single crystals, which are generally more expensive and difficult to prepare in comparison with polycrystals. Therefore, it is highly desirable to search polycrystalline materials with high RMCE. Here, the textured HoNiSi polycrystal is reported to show a giant RMCE, e.g., the rotating magnetic entropy change (−ΔSR) are 18.5 and 26.7 J/kg K and rotating adiabatic temperature change (ΔTR) are 7.0 and 13.4 K under 2 and 5 T, respectively. This giant RMCE over a wide temperature range especially under low field suggests textured HoNiSi as promising material for practical application of rotary magnetic refrigeration. Moreover, the large magnetic anisotropy of HoNiSi is explained by the single-ion magnetic anisotropy theory, and the coherent orientation of crystallographic texture and rare-earth ion moments leads to the large RMCE in the textured HoNiSi polycrystal. This work reveals that the strongly coherent orientation of crystallographic texture and rare-earth ion moments is a key to realize large RMCE in polycrystalline materials.

CO2-controlled assembly of conjugated polymer and boron nitride (BN) was fabricated via electrostatic and hydrophobic interactions between the BN fiber and conjugated polymer of PFBT containing fluorene units and 2,1,3-benzothiadiazole units. CO2, an effective and green stimulus for regulating the assembly of PFBT and BN fibers, leads to an obvious fluorescence variation. Moreover, PFBT enables the assembly with the signal amplification and light-harvesting properties. This work provides a new triggering method to construct intelligent conjugated polymer-based platform, and offers fluorescence monitoring strategy for carbon dioxide capture.

Both of carbon dioxide (CO2) and near-infrared (NIR) light as triggers for non-invasive remotely control are attracting wide attentions due to their good biocompatibility and easy operation. Here, CO2/NIR light dual controlled nanoparticles are proposed to remotely regulate the unzipping of dsDNA by using imidazole functionalized conjugated polymer nanoparticles (imidazole-CPNs). The dsDNA successfully coats on the shell of imidazole-CPNs to form imidazole-CPNs/dsDNA assembly due to intensively electrostatic interaction triggered by CO2. Furthermore, the unzipping process of dsDNA is remotely controlled by NIR light based on the photothermal effect, and it can be readily monitored by the fluorescence intensity of ethidium bromide (EB) and CD spectra of dsDNA. Thus, dual stimulation responsive imidazole-CPNs effectively control dsDNA unzipping under CO2 stimulus and NIR light, promising a new direction in the biological applications of DNA, such as the treatments of diseases caused by gene duplication abnormality.

Graphene quantum dots (GQDs) have been successfully used as a highly sensitive probe for the sensing of formaldehyde (HCHO) in an aqueous solution. Through static quenching, the probe utilizes the interaction between HCHO and GQDs to trigger the “turn off” fluorescence response, and has good selectivity. The probe can detect HCHO in a pure aqueous solution, and it also can still detect HCHO in a complex environment with a pH range from 4 to 10. The concentration of HCHO and the fluorescence intensity of GQDs show a good linear relationship within the range of HCHO of 0–1 μg/mL, which was much more sensitive than previous reports. The limit of HCHO detection by GQDs is about 0.0515 μg/mL. In addition, we successfully applied it to the actual food inspection. It is proved to be a selective, sensitive and visualized method to check whether the concentration of HCHO in the foods exceeds the regulatory limit, which presents a potential application in food safety testing.

The effects of Cu substitution for Ni atoms on the magnetic and magnetocaloric properties have been investigated in Mn0.8Fe0.2Ni1-xCuxGe (x = 0.05–0.3) compounds. The substitution of Cu leads to the larger separation of Mn atoms, which stabilizes the hexagonal phase and thus reduces the structural transition temperature Tstr. Moreover, the larger separation of nearest-neighbor Mn atoms weakens the ferromagnetic (FM) coupling in TiNiSi-type orthorhombic phase and results in the spiral antiferromagnetic (AFM) and more antiparallel AFM state with increasing Cu content. Similarly, the Ni2In-type hexagonal phase also changes from FM state to weak-magnetic spin-glass-like state with the introduction of Cu. The x = 0.05 compound shows a conventional magnetocaloric effect (MCE) due to the magnetostructural transformation from PM hexagonal phase to FM orthorhombic phase. On the contrary, the x = 0.1 compound undergoes the antiferromagnetically magnetostructural transition from FM hexagonal phase to AFM orthorhombic phase, which leads to a high inverse MCE. This large inverse MCE could be utilized in novel magnetic refrigerator to improve the refrigeration efficiency and applied for magnetic refrigeration of natural gas liquefaction.

The magnetic and rotating magnetocaloric properties in textured Tb3NiGe2 compound were investigated. Two successive magnetic transitions, a ferrimagnetic to antiferromagnetic (AFM)-like transition at Tt = 130 K and an AFM to paramagnetic (PM)-like transition at TN = 144 K, are observed. Besides, a magnetic-field-induced antiferromagnetic-ferromagnetic metamagnetic transition occurs in the temperature range of Tt ∼ TN. Large rotating magnetic entropy changes, together with considerable adiabatic temperature changes and refrigeration capacity, are obtained in textured Tb3NiGe2 compound. Moreover, the equivalence of different calculation methods for rotating magnetocaloric effect (RMCE) is discussed mathematically. The large RMCE with excellent thermal and magnetic reversibility suggests textured Tb3NiGe2 compound as an attractive candidate for novel magnetic refrigerant.

The synthetic control over pore structure and multifunctionality remain highly desirable for conjugated microporous polymers (CMPs). Here, we demonstrate that the 1,10-phenanthroline-like S,N-heter...

A drug carrier system of the hybrid nanoparticles based on the redox-responsive P[(2-((2-((camptothecin)-oxy)ethyl)disulfanyl)ethylmethacrylate)- co -(2-( d -galactose)methylmethacryl-ate)] (P(MACPTS- co -MAGP)) and AgNPs is developed to deliver the anti-cancer drug camptothecin (CPT) and monitor the drug release by the recovery of the fluorescence of CPT. CPT is linked to the polymer side-chains via a redox-responsive disulfide bond, attaching on the surface of AgNPs and leading to the quenching of CPT fluorescence (“off” state) due to the nanoparticle surface energy transfer (NSET) effect. Upon the exposure to glutathione (GSH), the disulfide bond is cleaved to release CPT, resulting in the recovery of the fluorescence of CPT (“on” state). The system offers a platform to track the CPT delivery and releasing in real time

Textured Ho2GdAl2 alloy exhibits highly anisotropic magnetic properties due to the coexistence of preferred crystallographic orientation and magnetocrystalline anisotropy (MCA). The variation in MCA energy (Ea) induced by the rotation of textured Ho2GdAl2 from a perpendicular to parallel direction under constant field results in a rotating magnetocaloric effect (MCE), which is larger than the conventional MCE. Moreover, the peaks of rotating magnetic entropy change (ΔSR) and rotating adiabatic temperature change (ΔTad,R) broaden asymmetrically towards low temperatures due to the different variation of MCA below and above the Curie temperature TC, thus leading to a table-like rotating MCE over the liquefaction temperature of natural gas.

Hybrid nanocomposites consisting of uniform Fe 3 O 4 nanoparticles and boron nitride (BN) nanospheres were synthesized via an ethanol-thermal reaction method. The spherical BN nanoparticles (BNNSs) with average diameter 150 nm have been uniformly coated with dense ultra-small Fe 3 O 4 nanoparticles (with average diameter of 10 nm), forming novel Fe 3 O 4 @BNNS nanocomposites. Magnetic measurement by using vibrating sample magnetometer (VSM) indicates that the Fe 3 O 4 coating is superparamagnetic, and the nanocomposites can be physically manipulated at a low magnetic field. Preliminary biocompatibility study has also been performed to evaluate the toxicity of the nanocomposites. The nanocomposites show cytocompatibility at low concentration and have little effect on cell viability of MCF-7, MCF-10 and Hela cell lines. The Fe 3 O 4 @BNNS nanocomposites may find a wide range of potential applications including water treatment, catalysts, carriers for boron neutron capture therapy and magnetic-targeted drug delivery.

The effect of different atomic substitutions at Mn sites on the magnetic and magnetocaloric properties in Ni50Mn35Co2Sn13 alloy has been studied in detail. The substitution of Ni or Co for Mn atoms might lower the Mn content at Sn sites, which would reduce the d-d hybridization between Ni 3d eg states and the 3d states of excess Mn atoms at Sn sites, thus leading to the decrease of martensitic transformation temperature TM in Ni51Mn34Co2Sn13 and Ni50Mn34Co3Sn13 alloys. On the other hand, the substitution of Sn for Mn atoms in Ni50Mn34Co2Sn14 would enhance the p-d covalent hybridization between the main group element (Sn) and the transition metal element (Mn or Ni) due to the increase of Sn content, thus also reducing the TM by stabilizing the parent phase. Due to the reduction of TM, a magnetostructural martensitic transition from FM austenite to weak-magnetic martensite is realized in Ni51Mn34Co2Sn13 and Ni50Mn34Co2Sn14, resulting in a large magnetocaloric effect around room temperature. For a low field change of 3 T, the maximum ∆SM reaches as high as 30.9 J/kg K for Ni50Mn34Co2Sn14. A linear dependence of &Delta, SM upon &mu, 0H has been found in Ni50Mn34Co2Sn14, and the origin of this linear relationship has been discussed by numerical analysis of Maxwell&rsquo, s relation.

A novel magnetic/fluorometric bimodal sensor was built from carbon dots (CDs) and MnO2. The resulting sensor was sensitive to glutathione (GSH), leading to apparent enhancement of magnetic resonance (MR) and fluorescence signals along with visual changes. The bimodal detection strategy is based on the decomposition of the CDs-MnO2 through a redox reaction between GSH and MnO2. This process causes the transformation from non-MR-active MnO2 to MR-active Mn(2+), and is accompanied by fluorescence restoration of CDs. Compared with a range of other CDs, the polyethylenimine (PEI) passivated CDs (denoted as pCDs) were suitable for detection due to their positive surface potential. Cross-validation between MR and fluorescence provided detailed information regarding the MnO2 reduction process, and revealed the three distinct stages of the redox process. Thus, the design of a CD-based sensor for the magnetic/fluorometric bimodal detection of GSH was emphasized for the first time. This platform showed a detection limit of 0.6 μM with a linear range of 1-200 μM in the fluorescence mode, while the MR mode exhibited a linear range of 5-200 μM and a GSH detection limit of 2.8 μM with a visible change being observed rapidly at 1 μM in the MR images. Furthermore, the introduction of the MR mode allowed the biothiols to be easily identified. The integration of CD fluorescence with an MR response was demonstrated to be promising for providing detailed information and discriminating power, and therefore extend the application of CDs in sensing and imaging.

Thermosensitive polymers show an entropy-driven transition from a well-solvated to a poorly solvated polymer chain, resulting in a more compact globular conformation. The transition at the lower critical solution temperature (LCST) is often sharp, which allows for a wide range of smart material applications. At the LCST, oligo(ethylene glycol)-substituted polyisocyanides (PICs) form soft hydrogels, composed of polymer bundles similar to biological gels, such as actin, fibrin and intermediate filaments. Here, we show that the LCST of PICs strongly depends linearly on the length of the ethylene glycol (EG) tails; every EG group increases the LCST and thus the gelation temperature by nearly 30 °C. Using a copolymerisation approach, we demonstrate that we can precisely tailor the gelation temperature between 10 °C and 60 °C and, consequently, tune the mechanical properties of the PIC gels.

An assembly was fabricated and was revealed to be a multiple-stimulus-responsive biomimetic hybrid polymer architecture. It was constructed by the hydrophobic interactions between a conjugated polyfluorene that contained 2,1,3-benzothiadiazole units (PFBT) and a tri(ethylene glycol)-functionalized polyisocyanopeptide (3OEG-PIC). The introduction of PFBT to the polyisocyanopeptide (PIC) network allowed for the incorporation of responsiveness to multiple stimuli including temperature, CO2 , carbonic anhydrase, and nonlinear mechanics, which mimics natural processes and interactions. Furthermore, the light-harvesting and signal amplification characteristics of PFBT endowed the supramolecular assembly with the essential function of fluorescence monitoring for biological processes.

A conjugated polymer centered on fluorene and 2,1,3-benzothia-diazole (PFBT) is prepared for sensing CO2 in situ with high sensitivity and low background. Upon introducing CO2, the weaker electrostatic repulsion and stronger hydrophobic interactions between neighboring PFBT molecules enhance the interchain contacts compared to that without CO2, leading to the energy transfer from fluorene to 2,1,3-benzothia-diazole sites and the emission color shift from blue to green, which is sensitive to sensing CO2 in atmospheric air with a content of ∼400 ppm. Importantly, PFBT is employed to monitor photosynthesis and respiration upon cycling day and night in situ.

The CO2 -responsive and biocatalytic assembly based on conjugated polymers has been demonstrated by combining the signal amplification property of the polythiophene derivative (PTP) and the catalytic actions of carbonic anhydrase (CA). CO2 is applied as a new trigger mode to construct the smart assembly by controlling the electrostatic and hydrophobic interactions between the PTP molecules in aqueous solution, leading to the visible fluorescence changes. Importantly, the assembly transformation of PTP can be specifically and highly accelerated by CA based on the efficient catalytic activity of CA for the inter-conversion between CO2 and HCO3- , mimicking the CO2 -associated biological processes that occurred naturally in living organisms. Moreover, the PTP-based assembly can be applied for biomimetic CO2 sequestration with fluorescence monitoring in the presence of CA and calcium.