Reliable detection of malachite green by self-assembled SERS substrates based on gold-silicon heterogeneous nano pineapple structures.

Morphology regulation of heterodimer nanoparticles and the use of their asymmetric features for further practical applications are crucial because of the rich optical properties and various combinations of heterodimers. This work used silicon to asymmetrically wrap half of a gold sphere and grew gold branches on the bare gold surface to form heterogeneous nano pineapples (NPPs) which can effectively improve Surface-enhanced Raman scattering (SERS) properties through chemical enhancement and lightning-rod effect respectively. The asymmetric structures of NPPs enabled them to self-assemble into the monolayer membrane with consistent branch orientation. The prepared substrate had high homogeneity and better SERS ability than disorganized substrates, and achieved reliable detection of malachite green (MG) in clams with a detection limit of 7.8 × 10-11 M. This work provided a guide to further revise the morphology of heterodimers and a new idea for the use of asymmetric dimers for practically photochemical and biomedical sensing.

Discovery of a series of portimine-A fatty acid esters in mussels.

Vulcanodinium rugosum is a benthic dinoflagellate known for producing pinnatoxins, pteriatoxins, portimines and kabirimine. In this study, we aimed to identify unknown analogs of these emerging toxins in mussels collected in the Ingril lagoon, France. First, untargeted data acquisitions were conducted by means of liquid chromatography coupled to hybrid quadrupole-orbitrap mass spectrometry. Data processing involved a molecular networking approach, and a workflow dedicated to the identification of biotransformed metabolites. Additionally, targeted analyses by liquid chromatography coupled to triple quadrupole mass spectrometry were also implemented to further investigate and confirm the identification of new compounds. For the first time, a series of 13-O-acyl esters of portimine-A (n = 13) were identified, with fatty acid chains ranging between C12:0 and C22:6. The profile was dominated by the palmitic acid conjugation. This discovery was supported by fractionation experiments combined with the implementation of a hydrolysis reaction, providing further evidence of the metabolite identities. Furthermore, several analogs were semi-synthesized, definitively confirming the discovery of these metabolization products. A new analog of pinnatoxin, with a molecular formula of C42H65NO9, was also identified across the year 2018, with the highest concentration observed in August (4.5 µg/kg). The MS/MS data collected for this compound exhibited strong structural similarities with PnTX-A and PnTX-G, likely indicating a substituent C2H5O2 in the side chain at C33. The discovery of these new analogs will contribute to deeper knowledge of the chemodiversity of toxins produced by V. rugosum or resulting from shellfish metabolism, thereby improving our ability to characterize the risks associated with these emerging toxins.

Mussel-Inspired Polymer-Based Coating Technology for Antifouling and Antibacterial Properties.

Zwitterionic coatings provide a promising antifouling strategy against biofouling adhesion. Quaternary ammonium cationic polymers can effectively kill bacteria on the surface, owing to their positive charges. This strategy can avoid the release of toxic biocides, which is highly desirable for constructing coatings for biomedical devices. The present work aims to develop a facile method by covalently grafting zwitterionic and cationic copolymers containing aldehydes to the remaining amine groups of self-polymerized dopamine. Reversible addition-fragmentation chain transfer polymerization was used to copolymerize either zwitterionic 2-methacryloyloxyethyl phosphorylcholine monomer (MPC) or cationic 2-(methacryloyloxy)ethyl trimethylammonium monomer (META) with 4-formyl phenyl methacrylate monomer (FPMA), and the formed copolymers poly(MPC-st-FPMA) and poly(META-st-FPMA) are denoted as MPF and MTF, respectively. MPF and MTF copolymers were then covalently grafted onto the amino groups of polydopamine-coated surfaces. PDA/MPF/MTF-coated surfaces exhibited antibacterial and antifouling properties against S. aureus, E. coli, and bovine serum albumin protein. In addition, they showed excellent viability of normal human lung fibroblast cells MRC-5. We expect the facile surface modification strategy discussed here to be applicable to medical device manufacturing.

Probiotics from kefir: Evaluating their immunostimulant and antioxidant potential in the carpet shell clam (Ruditapesdecussatus).

This study aimed to investigate the impact of incorporating kefir into the diet on biometric parameters, as well as the immune and antioxidant responses of the carpet shell clam (Ruditapes decussatus) after an experimental infection by Vibrio alginolyticus. Clams were divided into a control group and a treated group. The control group was fed on spirulina (Arthrospira platensis) alone. While, the treated group was fed on spirulina supplemented with 10% dried kefir. After 21 days, clams were immersed in a suspension of V. alginolyticus 5 × 105 CFU mL -1 for 30 min. Seven days after experimental infection, survival was 100% in both groups. The obtained results showed a slight increase in weight and condition index in clams fed with kefir-supplemented diet for 21 days compared to control clams. Regarding antioxidant responses, the treated group showed higher superoxide dismutase activity compared to the control group. However, the malondialdehyde level was lower in the treated clams than in the control. In terms of immune parameters, the treated group showed slightly elevated activities of phenoloxidase, lysozyme and alkaline phosphatase, whereas a decreased lectin activity was observed compared to the control group. The obtained results suggest that kefir enhanced both the antioxidant and immune response of infected clams.

Mussel-Mimetic Hydrogel Coating with Anticoagulant and Antiinflammatory Properties on a Poly(lactic acid) Vascular Stent.

Biodegradable stents are the most promising alternatives for the treatment of cardiovascular disease nowadays, and the strategy of preparing functional coatings on the surface is highly anticipated for addressing adverse effects such as in-stent restenosis and stent thrombosis. Yet, inadequate mechanical stability and biomultifunctionality limit their clinical application. In this study, we developed a multicross-linking hydrogel on the polylactic acid substrates by dip coating that boasts impressive antithrombotic ability, antibacterial capability, mechanical stability, and self-healing ability. Gelatin methacryloyl, carboxymethyl chitosan, and oxidized sodium alginate construct a double-cross-linking hydrogel through the dynamic Schiff base chemical and in situ blue initiation reaction. Inspired by the adhesion mechanism employed by mussels, a triple-cross-linked hydrogel is formed with the addition of tannic acid to increase the adhesion and antibiofouling properties. The strength and hydrophilicity of hydrogel coating are regulated by changing the composition ratio and cross-linking degree. It has been demonstrated in tests in vitro that the hydrogel coating significantly reduces the adhesion of proteins, MC3T3-E1 cells, platelets, and bacteria by 85% and minimizes the formation of blood clots. The hydrogel coating also exhibits excellent antimicrobial in vitro and antiinflammatory properties in vivo, indicating its potential value in vascular intervention and other biomedical fields.

Mussel-inspired interface deposition strategy for mesoporous metal-phenolic nanospheres with superior antioxidative, photothermal and antibacterial performance.

Metal-phenolic networks (MPNs) have emerged as a versatile and multifunctional platform applied in bioimaging, disease treatment, electrocatalysis, and water purification. The synthesis of MPNs with mesoporous frameworks and ultra-small diameters (<200 nm), crucial for post-modification, cargo loading, and mass transport, remains a formidable challenge. Inspired by mussel chemistry, mesoporous metal-phenolic nanospheres (MMPNs) are facilely prepared by direct deposition of the metal-polyphenol complex on the interface of oil nano-droplets composed of block copolymers/1,3,5-trimethylbenzene followed by a spontaneous template-removal process. Due to the penetrable and stable networks, the oil nano-droplets gradually leak from the networks driven by shear stress during the stirring process. As a result, MMPNs are obtained without additional template removal procedures such as solvent extraction or high-temperature calcination. The materials have a large pore size (∼12.1 nm), uniform spherical morphology with a small particle size (∼99 nm), and a large specific surface area (49.8 m2 g-1). Due to the abundant phenolic hydroxyl groups, the MMPNs show excellent antioxidative property. The MMPNs also have excellent photothermal property, whose photothermal conversion efficiency was 40.9 %. Moreover, the phenolic hydroxyl groups can reduce Ag+ in situ to prepare Ag nanoparticles loaded MMPNs composites, which have excellent inhibition performance of drug-resistant bacteria biofilm.

Exposure to environmental pharmaceuticals affects the macromolecular composition of mussels digestive glands.

Human pharmaceuticals represent a major challenge in natural environment. A better knowledge on their mechanisms of action and adverse effects on cellular pathways is fundamental to predict long-term consequences for marine wildlife. The FTIRI Imaging (FTIRI) spectroscopy represents a vibrational technique allowing to map specific areas of non-homogeneous biological samples, providing a unique biochemical and ultrastructural fingerprint of the tissue. In this study, FTIRI technique has been applied, for the first time, to characterize (i) the chemical building blocks of digestive glands of Mytilus galloprovincialis, (ii) alterations and (iii) resilience of macromolecular composition, after a 14-days exposure to 0.5 µg/L of carbamazepine (CBZ), valsartan (VAL) and their mixture, followed by a 14-days recovery period. Spectral features of mussels digestive glands provided insights on composition and topographical distribution of main groups of biological macromolecules, such as proteins, lipids, and glycosylated compounds. Pharmaceuticals caused an increase in the total amount of protein and a significant decrease of lipids levels. Changes in macromolecular features reflected the modulation of specific molecular and biochemical pathways thus supporting our knowledge on mechanisms of action of such emerging pollutants. Overall, the applied approach could represent an added value within integrated strategies for the effects-based evaluation of environmental contaminants.

Temporal variation in the concentrations and profiles of paralytic shellfish toxins and tetrodotoxin in scallop (Mizuhopecten yessoensis) and bloody clam (Anadara broughtonii) collected from the coast of Miyagi Prefecture, Japan.

For food safety, the concentrations and profiles of paralytic shellfish toxins (PSTs) and tetrodotoxin were examined in economically important scallops and bloody clams collected from the coast of the Miyagi Prefecture, Japan. PSTs were the major toxins in both species. The tetrodotoxin concentration in scallops increased in summer, although the highest value (18.7 µg/kg) was lower than the European Food Safety Authority guideline threshold (44 µg/kg). This confirmed the safety for tetrodotoxin in this area.

The First High-Quality Genome Assembly of Freshwater Pearl Mussel Sinohyriopsis cumingii: New Insights into Pearl Biomineralization.

China leads the world in freshwater pearl production, an industry in which the triangle sail mussel (Sinohyriopsis cumingii) plays a pivotal role. In this paper, we report a high-quality chromosome-level genome assembly of S. cumingii with a size of 2.90 Gb-the largest yet reported among bivalves-and 89.92% anchorage onto 19 linkage groups. The assembled genome has 37,696 protein-coding genes and 50.86% repeat elements. A comparative genomic analysis revealed expansions of 752 gene families, mostly associated with biomineralization, and 237 genes under strong positive selection. Notably, the fibrillin gene family exhibited gene family expansion and positive selection simultaneously, and it also exhibited multiple high expressions after mantle implantation by transcriptome analysis. Furthermore, RNA silencing and an in vitro calcium carbonate crystallization assay highlighted the pivotal role played by one fibrillin gene in calcium carbonate deposition and aragonite transformation. This study provides a valuable genomic resource and offers new insights into the mechanism of pearl biomineralization.

Determination of lipophilic marine biotoxins (azaspiracids, brevetoxins, and okadaic acid group) and domoic acid in mussels by solid-phase extraction and reversed-phase liquid chromatography with tandem mass spectrometry.

An accurate and efficient method was developed for the determination of azaspiracid shellfish toxins (azaspiracids-1, -2, and -3), neurotoxic shellfish toxins (brevetoxins-2 and -3), diarrhetic shellfish toxins (okadaic acid and dinophysistoxins-1 and -2), and the amnesic shellfish toxin (domoic acid) in mussels (Mytilus galloprovincialis). Lipophilic marine biotoxins (azaspiracids, brevetoxins, and okadaic acid group) were extracted with 0.5 % acetic acid in methanol under heating at 60°C to improve the extraction efficiency of okadaic acid group toxins and then cleaned up with a C18 solid-phase extraction cartridge. Domoic acid was extracted with 50 % aqueous methanol and then cleaned up with a graphitized carbon solid-phase extraction cartridge. Lipophilic marine biotoxins and domoic acid were quantified by reversed-phase liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The developed method had insignificant matrix effects for the nine analytes and good recoveries in the range of 79.0 % to 97.6 % at three spiking levels for all analytes except brevetoxin-2 (43.8-49.8 %). The developed method was further validated by analyzing mussel tissue certified reference materials, and good agreement was observed between certified and determined values.

Optimization of a fast and sensitive method based on matrix solid-phase dispersion-LC-ms/ms for simultaneous determination of phthalates and bisphenols in mussel samples.

Bisphenols and phthalates are wide classes of endocrine disrupting chemicals (EDCs) extensively used as additives in plastic products. In this study, a fast and reliable analytical method based on matrix solid-phase dispersion (MSPD) coupled with LC-MS/MS was developed and optimized for simultaneous determination of 8 bisphenols and 7 phthalates in raw mussel extract. The LC-MS/MS method was tested for linearity (R2), inter- and intra-day repeatability, limit of detection and quantification, both for matrix-free and matrix-matched solutions. The MSPD method was optimized in terms of ratio between sample and sorbent, and the type and quantity of the eluents in order to maximize the recoveries and to minimize matrix effects. The obtained recoveries (values between 75% and 113%), limits of detection (values between 0.048 and 0.36 µg kg-1), limits of quantification (values between 0.16 and 1.28 µg kg-1), repeatability (RSD% between 1.30% and 8.41%) and linearity (R2 > 0.998) were satisfactory and suitable for the determination of target micropollutants in food samples. In addition, the low solvent consumption and fast execution make this method ideal for routinely determinations of bisphenols and phthalates in mussels.

Carbamoylase-based impedimetric electronic tongue for rapid detection of paralytic shellfish toxins.

Phytotoxins produced by marine microalgae, such as paralytic shellfish toxins (PSTs), can accumulate in bivalve molluscs, representing a human health concern due to the life-threatening symptoms they cause. To avoid the commercialization of contaminated bivalves, monitoring programs were established in the EU. The purpose of this work is the implementation of a PST transforming enzyme-carbamoylase-in an impedimetric test for rapid simultaneous detection of several carbamate and N-sulfocarbamoyl PSTs. Carbamoylase hydrolyses carbamate and sulfocarbamoyl toxins, which may account for up to 90% of bivalve toxicity related to PSTs. Conformational changes of carbamoylase accompanying enzymatic reactions were probed by Fourier transform mid-infrared spectroscopy (FT-MIR) and electrochemical impedance spectroscopy (EIS). Furthermore, a combination of EIS with a metal electrode and a carbamoylase-based assay was employed to harness changes in the enzyme conformation and adsorption on the electrode surface during the enzymatic reaction as an analytical signal. After optimization of the working conditions, the developed impedimetric e-tongue could quantify N-sulfocarbamoyl toxins with a detection limit of 0.1 µM. The developed e-tongue allows the detection of these toxins at concentration levels observed in bivalves with PST toxicity close to the regulatory limit. The quantification of a sum of N-sulfocarbamoyl PSTs in naturally contaminated mussel extracts using the developed impedimetric e-tongue has been demonstrated.

Seasonal profile of common pharmaceuticals in edible bivalve molluscs.

Pharmaceuticals are recognised as environmental contaminants of emerging concern (CECs) due to their increasing presence in the aquatic environment, along with high bioactivity linked to their therapeutic use. Therefore, information on environmental levels is urgently required. This study examined the presence of a range of common pharmaceuticals in oysters and mussels intended for human consumption from England and Wales using stable isotope dilution tandem mass spectrometry. A range of compounds were detected in bivalve tissue, with the Selective Serotonin Reuptake Inhibitor antidepressant sertraline being most abundant, reaching a maximum concentration of 22.1 ng/g wet weight shellfish tissue. Levels of all pharmaceuticals showed seasonal and geographical patterns. A dietary risk assessment revealed that the levels of pharmaceuticals identified in bivalve molluscs represent a clear hazard, but not a risk for the consumer. This study highlights the requirement for further monitoring of the presence of pharmaceuticals and other CECs in bivalve molluscs.

Contamination Status and Risk Assessment of Paralytic Shellfish Toxins in Shellfish along the Coastal Areas of China.

Paralytic shellfish toxins (PSTs) are widely distributed in shellfish along the coast of China, causing a serious threat to consumer health; however, there is still a lack of large-scale systematic investigations and risk assessments. Herein, 641 shellfish samples were collected from March to November 2020, and the PSTs' toxicity was detected via liquid chromatography-tandem mass spectrometry. Furthermore, the contamination status and potential dietary risks of PSTs were discussed. PSTs were detected in 241 shellfish samples with a detection rate of 37.60%. The average PST toxicities in mussels and ark shells were considerably higher than those in other shellfish. The PSTs mainly included N-sulfonylcarbamoyl toxins (class C) and carbamoyl toxins (class GTX), and the highest PST toxicity was 546.09 µg STX eq. kg-1. The PST toxicity in spring was significantly higher than those in summer and autumn (p < 0.05). Hebei Province had the highest average PST toxicity in spring. An acute exposure assessment showed that consumers in Hebei Province had a higher dietary risk, with mussels posing a significantly higher dietary risk to consumers. This research provides reference for the green and sustainable development of the shellfish industry and the establishment of a shellfish toxin prevention and control system.

Protective Topical Dual-Sided Nanofibrous Hemostatic Dressing Using Mussel and Silk Proteins with Multifunctionality of Hemostasis and Anti-Bacterial Infiltration.

Topical hemostatic agents are preferred for application to sensitive bleeding sites because of their immediate locoregional effects with less tissue damage. However, the majority of commercial hemostatic agents fail to provide stable tissue adhesion to bleeding wounds or act as physical barriers against contaminants. Hence, it has become necessary to investigate biologically favorable materials that can be applied and left within the body post-surgery. In this study, a dual-sided nanofibrous dressing for topical hemostasis is electrospun using a combination of two protein materials: bioengineered mussel adhesive protein (MAP) and silk fibroin (SF). The wound-adhesive inner layer is fabricated using dihydroxyphenylalanine (DOPA)-containing MAP, which promotes blood clotting by aggregation of hemocytes and activation of platelets. The anti-adhesive outer layer is composed of alcohol-treated hydrophobic SF, which has excellent spinnability and mechanical strength for fabrication. Because both proteins are fully biodegradable in vivo and biocompatible, the dressing would be suitable to be left in the body. Through in vivo evaluation using a rat liver damage model, significantly reduced clotting time and blood loss are confirmed, successfully demonstrating that the proposed dual-sided nanofibrous dressing has the right properties and characteristics as a topical hemostatic agent having dual functionality of hemostasis and physical protection.

Coacervate Phase Evolution and Membrane Formation in Natural Seawater.

Marine organisms produce biological materials through the complex self-assembly of protein condensates in seawater, but our understanding of the mechanisms of microstructure evolution and maturation remains incomplete. Here, we show that critical processing attributes of mussel holdfast proteins can be captured by the design of an amphiphilic, fluorescent polymer (PECHIA) consisting of a polyepichlorohydrin backbone grafted with 1-imidazolium acetonitrile. Aqueous solutions of PECHIA were extruded into seawater, wherein the charge repulsion of PECHIA is screened by high salinity, facilitating interfacial condensation via enhanced "cation-dipole" interactions. Diffusion of seawater into the PECHIA solution caused droplets to form immiscibly within the PECHIA phase (i.e., inverse coacervation). Simultaneously, weakly alkaline seawater catalyzes nitrile cyclization and time-dependent solidification of the PECHIA phase, leading to hierarchically porous membranes analogous to porous architectures in mussel plaques. In contrast to conventional polymer processing technologies, processing of this biomimetic polymer required neither organic solvents nor heating and enabled the template-free production of hollow spheres and fibers over a wide range of salinities.

Detection of paralytic shellfish toxins by near-infrared spectroscopy based on a near-Bayesian SVM classifier with unequal misclassification costs.

BACKGROUND: Paralytic shellfish poisoning caused by human consumption of shellfish fed on toxic algae is a public health hazard. It is essential to implement shellfish monitoring programs to minimize the possibility of shellfish contaminated by paralytic shellfish toxins (PST) reaching the marketplace. RESULTS: This paper proposes a rapid detection method for PST in mussels using near-infrared spectroscopy (NIRS) technology. Spectral data in the wavelength range of 950-1700 nm for PST-contaminated and non-contaminated mussel samples were used to build the detection model. Near-Bayesian support vector machines (NBSVM) with unequal misclassification costs (u-NBSVM) were applied to solve a classification problem arising from the fact that the quantity of non-contaminated mussels was far less than that of PST-contaminated mussels in practice. The u-NBSVM model performed adequately on imbalanced datasets by combining unequal misclassification costs and decision boundary shifts. The detection performance of the u-NBSVM did not decline as the number of PST samples decreased due to adjustments to the misclassification costs. When the number of PST samples was 20, the G-mean and accuracy reached 0.9898 and 0.9944, respectively. CONCLUSION: Compared with the traditional support vector machines (SVMs) and the NBSVM, the u-NBSVM model achieved better detection performance. The results of this study indicate that NIRS technology combined with the u-NBSVM model can be used for rapid and non-destructive PST detection in mussels. © 2023 Society of Chemical Industry.

Occurrence and risk assessment of okadaic acid, dinophysistoxin-1, dinophysistoxin-2, and dinophysistoxin-3 in seafood from South Korea.

The okadaic acid (OA)-group toxins, including OA, dinophysistoxin-1 (DTX1), dinophysistoxin-2 (DTX2), and dinophysistoxin-3 (DTX3), cause diarrheic shellfish poisoning in humans. To manage OA-group toxins more strictly, Korean regulations were recently revised to consider OA, DTX1, DTX2, and DTX3 combined. Thus, our study characterized the occurrence of OA, DTX1, DTX2, and DTX3 in seafood distributed across South Korea, and a risk assessment of seafood consumption was conducted. Two hundred and seventeen samples from 16 bivalve and 7 non-bivalve species collected from three representative coastal areas in 2021 were analyzed via liquid chromatography-tandem mass spectrometry. OA, DTX1, and DTX3 were detected in 2.3%, 4.1%, and 9.2% of the examined samples, with positive mean levels of 11.3, 16.4, and 40.9 µg/kg, respectively. DTX2 was not detected in any of the samples. At least one OA-group toxin was detected in the bivalve samples, including blood clams, pan shells, hard clams, mussels, and scallops, whereas none were detected in non-bivalves. The estimated acute exposure to OA-group toxins through the intake of seafood in the Korean population and consumer groups was low, ranging from 24.7 to 74.5% of the recommended acute reference dose (ARfD) of 0.33 µg OA equivalents/kg body weight. However, for the scallop consumers aged 7-12 years, acute exposure to OA-group toxins exceeded the ARfD, indicating a possible health risk. These results suggest that including DTX3 in the new regulatory limits is appropriate to protect Korean seafood consumers from exposure to OA-group toxins.

Untargeted Metabolomics Analyses and Contaminant Chemistry of Dreissenid Mussels at the Maumee River Area of Concern in the Great Lakes.

Bivalves serve as an ideal ecological indicator; hence, their use by the NOAA Mussel Watch Program to monitor environmental health. This study aimed to expand the baseline knowledge of using metabolic end points in environmental monitoring by investigating the dreissenid mussel metabolome in the field. Dreissenids were caged at four locations along the Maumee River for 30 days. The mussel metabolome was measured using nuclear magnetic resonance spectroscopy, and mussel tissue chemical contaminants were analyzed using gas or liquid chromatography coupled with mass spectrometry. All Maumee River sites had a distinct mussel metabolome compared to the reference site and revealed changes in the energy metabolism and amino acids. Data also highlighted the importance of considering seasonality or handling effects on the metabolome at the time of sampling. The furthest upstream site presented a specific mussel tissue chemical signature of pesticides (atrazine and metolachlor), while a downstream site, located at Toledo's wastewater treatment plant, was characterized by polycyclic aromatic hydrocarbons and other organic contaminants. Further research into the dreissenid mussel's natural metabolic cycle and metabolic response to specific anthropogenic stressors is necessary before successful implementation of metabolomics in a biomonitoring program.

Mussel-Inspired Cation-π Interactions: Wet Adhesion and Biomimetic Materials.

Cation-π interaction is one of the most important noncovalent interactions identified in biosystems, which has been proven to play an essential role in the strong adhesion of marine mussels. In addition to the well-known catecholic amino acid, l-3,4-dihydroxyphenylalanine, mussel foot proteins are rich in various aromatic moieties (e.g., tyrosine, phenylalanine, and tryptophan) and cationic residues (e.g., lysine, arginine, and histidine), which favor a series of short-range cation-π interactions with adjustable strengths, serving as a prototype for the development of high-performance underwater adhesives. This work highlights our recent advances in understanding and utilizing cation-π interactions in underwater adhesives, focusing on three aspects: (1) the investigation of the cation-π interaction mechanisms in mussel foot proteins via force-measuring techniques; (2) the modulation of cation-π interactions in mussel mimetic polymers with the variation of cations, anions, and aromatic groups; (3) the design of wet adhesives based on these revealed principles, leading to functional materials in the form of films, coacervates, and hydrogels with biomedical and engineering applications. This review provides valuable insights into the development and optimization of smart materials based on cation-π interactions.