Guiyin Zhou's research while affiliated with Central South University and other places

The maintenance of high load-bearing tissues and joint lubrication is essential for suppressing osteoarthritis. The lubrication of natural joints is mainly attributed to the hydration lubrication mechanism of articular cartilage. Phospholipids on the cartilage surface attract water molecules to form a tough hydrated layer to reduce friction. In this work, inspired by the phosphatidylcholine lipids, we synthesized lubricated nanospheres by grafting hydrophilic polymer brushes and further synthesized a nanocomposite hydrogel. The addition of the lubricated nanospheres enhanced both the mechanical and lubricated properties of the hydrogel. The nanocomposite-lubricated hydrogel exhibited a friction coefficient 81.7% lower than the blank hydrogel because of grafting the polymer brushes. Also, the nanocomposite enhancement helped the hydrogel achieve high mechanical properties with a compressive strength of 6.63 MPa (50%). The nanocomposite hydrogel developed here could be a promising candidate material in bionic articular cartilage substitute materials.

BACKGROUND The incompletely polymerized microgels play a crucial role during the formation of hydrogel. In this paper, a microgel (synthesized using Paecilomyces lilacinus and N‐isopropylacrylamide) was used as a cross‐linking agent to synthesize agar/poly (acrylamide‐co‐hydroxyethyl acrylate) double‐network (DN) hydrogel (NH2‐MRDN), which was further modified by triethylenetetramine. The physical and chemical properties of NH2‐MRDN were studied by SEM, FTIR, TGA, XPS, universal testing machine, and adsorption method. RESULTS The NH2‐MRDN has excellent mechanical properties and contains many hydroxy and amino groups. Adsorption experiments show that the NH2‐MRDN has better adsorption performance at pH 4 ~ 7 and that the interference ion has little effect on adsorption at low concentrations. In addition, the Kd for Pb(II) always had the highest values both in single component and mixed component for selective adsorption. The adsorption capacity values calculated by Langmuir model were 182.23 mg g⁻¹ for Pb(II) and 118.36 mg g⁻¹ for Cd(II), and they reached equilibrium in 160 and 240 min, respectively. Further, the mechanism and thermodynamic analysis showed that the adsorption process mainly relies on the hydroxyl and amine group, making it a spontaneous and endothermic adsorption process. CONCLUSION The NH2‐MRDN hydrogel reinforced by microgel overcame the poor stability of conventional adsorbents, and this is expected to provide a new method for the synthesis of hydrogel adsorbents. Meanwhile, this work supplies a theoretical basis and empirical evidence for the application and development of high polymer adsorbents. © 2023 Society of Chemical Industry (SCI).

Healthy articular cartilage can achieve high load-bearing capacity and the most effective lubricated surface. Inspired by the articular cartilage, a lipid-lubricated hydrogel with excellent mechanical strength and remarkable lubrication was designed and synthesized. The lipid-lubricated hydrogel could contribute to high strength and stiffness (compressive strength of 5.8 MPa and compressive modulus of 4.7 MPa at 50% strain), and it could recover more than 98% of original mechanical properties in a short time after loading-unloading. In addition, the friction coefficient of lipid-lubricated hydrogel is low as 0.026, 5.3 times smaller than hydrogel without adding the liposomes. Overall, the hydrogel we studied holds the potential as a load-bearing soft tissue substitute for articular cartilage.

Heavy metal pollution caused by the indiscriminate disposal of toxic heavy metal wastewater has become one of the serious water environmental issues. In this study, a novel NH2-PAA/Alginate hydrogel with double network interpenetrating structure was constructed with alginate, acrylic acid, and other raw materials. Characterized by scanning electron microscope, this hydrogel shows a three-dimensional porous structure, which would be useful in adsorption process for its high diffusion coefficient. The results of adsorption experimental show that the NH2-PAA/Alginate possessed the well adsorption capacity when pH was above 3.5, the maximum adsorption capacity calculated by Langmuir was 176.5 mg/g, and the adsorption equilibrium can be achieved within 150 min. In addition, the NH2-PAA/Alginate has good recycling ability and stability. The results of X-ray photoelectron spectroscope analysis reveal that the Cd(II) exchanged with Ca(II) and then coordinated with amino and hydroxyl groups in NH2-PAA/Alginate. The NH2-PAA/Alginate hydrogel can deal with all kinds of heavy metal ions and is a potential material for heavy metal adsorption.

An important issue in photocatalysis is the light required to carry out the catalytic reaction, so maintaining photocatalytic reaction activity in the dark has been the ultimate target of expanding photocatalytic technology. Herein, we report a photocatalyst g-C3N4/SrAl2O4:Eu²⁺,Dy³⁺ through a strategy that couples the energy-storing and light-releasing properties of long afterglow materials and the light-absorbing properties of photocatalytic materials. g-C3N4/SrAl2O4:Eu²⁺,Dy³⁺ is able to effectively degrade methyl orange in water under visible light using molecular oxygen in the air, but it maintains significant methyl orange degradation activity after the light is turned off, as if SAO acts as a built-in light source in it. The photocatalytic degradation mechanism is investigated by active species capture experiments, which shows that superoxide radicals (•O2⁻), hydroxyl radicals (•OH), holes (h⁺), and singlet oxygen (¹O2) generate during the photocatalytic process. Among them, •O2⁻ is the relatively predominantly acting reactive species. This study exemplifies the design of a continuously working photocatalyst with conceptual value for light storage, which provides ideas for practical energy and environmental system applications.

A simple, sensitive and accurate reversed-phase high-performance liquid chromatography (RP-HPLC) method was established for the determination of piperidine and piperidine hydrochloride in artane, using pre-column derivatization with 4-toluenesulfonyl chloride. The RP-HPLC method was carried out on a Inertsil C18 column (250 × 4.6 mm I.D.) maintained at 30°C. The mobile phase consisted of water with 0.1% phosphoric acid (phase A) and acetonitrile (phase B) (32:68, V:V) at a flow rate of 1.0 mL/min. Linearity of piperidine was found in the range of 0.44-53.33 μg/mL with R2 = 0.9996. The limit of detection was estimated to be 0.15 μg/mL, and the limit of quantitation was 0.44 μg/mL. The average recovery was 101.82% with relative standard deviations of 0.6% at three spiked levels. The developed method using HPLC-ultraviolet system was a rapid tool for routine analysis of piperidine in the bulk form with good accuracy.

In this work, we introduced a multifunctional Ag(I)/CAAA-amidphos complex catalyzed asymmetric 1,3-dipolar cycloaddition of acrylates with α-imino esters, affording a series of 2,4,5-trisubstituted endo-pyrrolidines in good yields (up to 97%) with high enantioselectivities (up to 98% ee). Meanwhile, the catalytic system was also applied in the three-component one-pot reaction of α-imino esters formed in situ under the action of N,N′-diisopropylcarbodiimide. In addition, the gram-scale reaction was realized for the formal synthesis of (+)-ibophyllidine in eight steps.