Incorporation of poly(dopamine) (PDA) into the native oligopeptide hydrogel has been demonstrated to decrease the critical gel concentration (CGC), improve the rigidity of formed hybrid hydrogel, and especially endow the hydrogel with efficient free radical scavenging ability.Inspired by nature, self-assembly strategy has been well developed to build various biomaterials in recent years. For example, self-assembly of DNA, 1,2 phospholipids, 3,4 proteins, 5,6 as well as peptides 7 has been widely exploited to construct different nanomaterials for drug/gene delivery, cell culture and tissue engineering. Among them, the oligopeptides with low molecular weights have attracted much attention in the eld of nanotechnology-assistant cancer treatments due to the mellow synthetic methods and adjustable amphipathy to fabricate shape-tailored nanomaterials via self-assembly. Of note, selfassembled oligopeptide hydrogel has been demonstrated as an interesting so material for biomedical applications. 8,9Nevertheless, restricted by the short sequences, most oligopeptides are lack of multiple bioactivity. On account of the noncovalent interactions, in addition, the hydrogel strength is usually far from satisfactory. 10,11To tackle these difficulties, various hybrid oligopeptide hydrogels have been developed to hold different synergistic properties. Incorporation of graphene oxide (GO) into a short peptide hydrogel improved the rigidity of the hybrid hydrogel system compared to the native one.12 The hybrid hydrogel constructed by GO sheets and an oligopeptide possessed high drug-sustainability and on-demand drug release in vivo. 13Doping FEFEFKFK peptide hydrogel with poly(Nisopropylacrylamide)-FEFEFKFK conjugate allowed for optimizing the mechanical properties of peptide-based hydrogels and endowed them with temperature sensitivity.14 Hybrid hydrogel compromising of an amphipathic oligopeptide and a uorescent p-conjugated poly(para-phenylene vinylene) exhibited strong uorescence, even higher than the pure polymer in solution.15 As anticipated, different functions have been achieved in those two-in-one hybrid systems. Nevertheless, the controversy on the toxicity of GO in vivo slows its progress toward clinical biomaterials.16-18 And preparing functional polymers sometimes needs tedious steps. Thus, functional polymers with good biocompatibility and simple fabrication process are highly pursued to construct novel hybrid oligopeptide hydrogels.Poly(dopamine) (PDA) owing to many functional groups such as catechol, amine, and imine exhibits robust adhesion to diverse substrates, which provides great potential as the coating materials.19,20 It has been well documented that PDA could adsorb various dye molecules due to the hydrogen bonding and p-p stacking interaction. 21,22 Recently, PDA has caused serious concerns in biomedical applications due to the outstanding biocompatibility and unique physicochemical properties. 23,24PDA has been demonstrated to be an efficient antioxidant in the biological system, which is associated wit...

Due to the problematic degradation properties of plastics, the decomposition of plastic results in the formation of numerous microplastics (MPs), less than 5 mm in diameter. These MPs enter the soil and the ocean, eventually passing through the air, water, or food chain back to the human body and harming human health. In the last 80 years, male semen analysis parameters have shown a significant decline for unknown reasons, speculated to be caused by pollutants. No studies examined the relationship between human MP exposure and male infertility. In this article, we reviewed the relevant animal experimental research literature in recent years and calculated that the minimum human equivalent dose of MPs leading to abnormal male semen quality is 0.016 mg/kg/d. The literature comparison found that MP exposure in Japan and South Korea was close to this value. These results suggest that MPs can affect male semen quality and that MPs may significantly impact male fertility.

This work demonstrates that proper selection of a metal ion and chelating ligand enables recovery of a his(6)-tagged protein from canola (Brassica napus) extracts by immobilized metal affinity chromatography (IMAC). When using Co(2+) with iminodiacetate (IDA) as the chelating ligand, beta-glucuronidase-his(6) (GUSH6) can be purified from canola protein extract with almost homogeneous purity in a single chromatographic step. The discrimination with which metal ions bound native canola proteins followed the order Cu(2+) < Ni(2+) < Zn(2+) < Co(2+) in regard to elimination of proteins coeluted with the fusion protein. IDA- and nitrilotriacetate (NTA)-immobilized metal ions showed different binding patterns, whose cause is attributed to a more rigid binding orientation of the his(6) in forming a tridentate with Me(2+)-IDA than in forming a bidentate with Me(2+)-NTA. The more flexible binding allows for multisite interactions over the protein.

etc. Among them, hyaluronic acid (HA)derived hydrogel is one of the ideal candidates due to its inherent biological homology, feasible structure modification, as well as good degradability. [9,10] The high water retention capacity and high viscoelasticity of HA also allow it to be suitable for wound dressings.To construct desirable HA-based hydrogels, different strategies have been established. Relying on the intermolecular noncovalent interactions, the physical cross-linking HA hydrogels emerged. Rodell et al. developed a shearthinning and self-healing HA hydrogel due to the host-guest interaction between β-cyclodextrin (β-CD) and adamantine (AD) appended HA. [11] The hydrogel properties could be rationally tailored through the material concentration, degree of modification, and the ratio of β-CD to AD. Nevertheless, the physical hydrogels may exhibit undesirable mechanical properties and suffer from premature dissociation. Chemical crosslinking of pendant reactive groups by coordination chemistry or polymerization ignites an alternative route to fabricate HAbased hydrogels. In the meanwhile, transition metal ions or exogenous cross-linking agents usually involve, [12] which may impair the systemic biocompatibility due to their possible cytotoxicity. Recently, various compatible strategies have been proposed to develop biocompatible hydrogels, such as enzymemediated covalent linking, [13,14] disulfide cross-linking, [15,16] and Diels-Alder reaction. [17,18] Indeed, these chemical cross-linked hydrogels exhibit good mechanical property and are cytocompatible. However, their further applications are restricted by their limited functions. Thus, endowing HA hydrogels with multiple functions seems to be very promising, and fabricating HA-based functional hydrogels with good biocompatibility is still challengeable.In this study, a multifunctional hydrogel (PDA-HA) comprising of polydopamine (PDA) and thiolated hyaluronic acid (HA-SH) is developed (Scheme 1). PDA was introduced because of its good biocompatibility, strong tissue adhesion and effective free radical scavenging ability. Specially, it could act as the nanosized cross-linking agent that reacts with thiolated HA via Michael addition. The biocompatibility, gelling ability, tissue adhesion, free radical scavenging, and bacterial inhibition of the hybrid hydrogel were evaluated. The potential bacterial inhibition and good tissue adhesion endow the hydrogel with great potential for wound dressing.As shown in Figure 1A, thiolated hyaluronic acid (HA-SH) was obtained by two steps that referred to the amidation of Hyaluronic acid (HA)-based hydrogels have been receiving increasing attention for wound management. However, pure HA hydrogels usually exhibit weak mechanical strength and poor anti-infection. Herein, a hybrid HA-based hydrogel (PDA-HA) comprised of polydopamine (PDA) and thiolated hyaluronic acid (HA-SH) is developed based on the Michael addition reaction. The introduction of PDA into HA hydrogel can decrease the critical gel concentration, improve the c...

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