Polydopamine Surface Chemistry: A Decade of Discovery

Biodegradable, electroconductive self-healing hydrogel based on polydopamine-coated polyurethane nano-crosslinker for Parkinson's disease therapy

Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons, causing motor and neurological impairments. Current treatments offer only temporary symptom relief without halting progression. Herein, a fully biodegradable, electroconductive self-healing hydrogel (CPUD gel) is developed, incorporating electroconductive polydopamine-coated polyurethane nanoparticles (PUD) as crosslinker. The core-shell PUD nanoparticles have a highly uniform size of ∼36 nm with a polydopamine shell of ∼4.8 nm thick on polyurethane core, revealed by small angle X-ray scattering, and own a conductivity of ∼0.82 mS/cm. As nano-crosslinker, the PUD can react with chitosan to form the dynamic CPUD hydrogel with shear modulus (∼280 Pa) and conductivity (∼4.34 mS/cm), mimicking brain tissue properties. In vitro, CPUD gel supports neural stem cell (NSC) proliferation (∼565 %) and differentiation, with elevated neuronal marker expression at 14 days, while exhibiting strong antioxidative and anti-inflammatory effects, rescuing ∼88 % inflamed NSCs. A therapeutic strategy combining injectable CPUD gel with acupuncture in a PD rat model, aiming to activate the innate regenerative mechanisms of body through mobilized endogenous stem cells, is further established. Using this approach, this hydrogel significantly elevates serum TGF-β1/SDF-1 levels, promotes dopaminergic neuron regeneration (>80 %), modulates neuroinflammation through M1-to M2-microglia transition (∼12.6-fold M2/M1 ratio), and improves motor function (from 8 % to 37 % forelimb contacts) in 14 days. Particularly, the electrophysiological spike rate is recovered from 66 to 19 spikes/s, close to the healthy rate 15 spikes/s. The synergistic immunomodulation and neuroprotection highlight the potential of CPUD gel as an advanced therapeutic tool for PD.

Boosting photocatalytic oxygen reduction to hydrogen peroxide via chemisorbed oxygen activation on polydopamine-coated zinc oxide

Harnessing solar energy to produce hydrogen peroxide (H2O2) from water (H2O) and dioxygen (O2) via artificial photosynthesis is an attractive route. However, the production of H2O2 is significantly hindered by slow mass transfer, primarily due to the low solubility and diffusion coefficient of O2 in water, particularly when the oxygen reduction reaction (ORR) predominates. To tackle this challenge, we propose that the polydopamine-coated zinc oxide nanoparticle with oxygen vacancies (PDA@ZnO1-x) core-shell photocatalyst exhibits excellent oxygen adsorption capability and promotes the two-electron reduction of O2. In-situ Electron paramagnetic resonance (EPR) and O2-Temperature-programmed desorption (TPD) confirmed that the semiquinone radicals (SQ•) within the PDA shell effectively chemisorb oxygen. Notably, PDA@ZnO1-x exhibited a high H2O2 production rate of 3.40 mM/h under visible light and an apparent quantum efficiency of 44.1 % at 400 nm. This work presents a significant strategy for improving oxygen utilization to achieve efficient photocatalytic production of H2O2.

Poly(lactide acid)-based microneedles enhanced by tunicate cellulose nanocrystals for potential diabetic periodontitis treatment

Diabetic periodontitis, characterized by persistent inflammation and impaired periodontal tissue regeneration under hyperglycemic conditions, urgently requires innovative therapeutic strategies. Microneedle (MN) technique has recently emerged as a promising solution for diabetic periodontitis by enabling minimally invasive and localized drug delivery. In this study, we developed poly(lactic acid) (PLA)-based MNs reinforced with PLA-grafted tunicate cellulose nanocrystals (TCNC-g-PLA@PLA-MNs), demonstrating favorable mechanical strength and biocompatibility. After loading with irisin and interleukin-1 (IL-1) receptor antagonist (IL-1ra) via surface polydopamine functionalization, the MNs exhibited anti-inflammatory effects by markedly reducing the expressions of IL-6 by 0.53-fold, IL-8 by 0.23-fold, and MCP-1 by 0.41-fold in human periodontal ligament cells (hPDLCs). Additionally, they significantly promoted osteogenic differentiation, increasing the expressions of ALP by 1.87-fold, OPN by 2.21-fold, OCN by 1.39-fold, and Runx2 by 2.28-fold, which was further supported by enhanced ALP staining. Furthermore, the MNs improved the migration ability of hPDLCs under inflammatory and high-glucose culture conditions. Our findings highlight that the TCNC-g-PLA@PLA-MNs effectively integrate structural reinforcement and therapeutic functionality, providing a novel and potential platform to promote periodontal regeneration in the context of diabetic periodontitis.

Dopamine-conjugated hyaluronic acid hydrogel interpenetrated by genipin crosslinked quaternary ammonium chitosan for potential biomedical adhesives applications

Multifunctional hydrogel adhesives have emerged as promising candidates for advanced biomedical applications, particularly in surgical suture alternatives, hemostatic management, and regenerative wound care. This study developed an interpenetrating polymer network (IPN) hydrogel adhesive system through the synergistic integration of dopamine-functionalized hyaluronic acid (HA-DA) and genipin-crosslinked quaternary ammonium chitosan (QCS). The successful preparation of HA-DA and QCS was confirmed via 1H nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR) analysis. The fabricated hydrogel adhesives exhibited the interconnected microstructure, suitable mechanical strength, and elastic solid properties. Additionally, the hydrogel adhesives exhibited expected self-healing abilities and injectability. The hydrogels displayed strong adhesion on different matrix and tissues. The quaternary ammonium group pendants in the hydrogel network result in the excellent antibacterial activity of hydrogels against Escherichia coli and Staphylococcus aureus. Furthermore, hemolysis test, fluorescence images, CCK-8 assay, and wound scratch assay demonstrated that the hydrogel adhesives possessed good hemocompatibility, biocompatibility, and cell migration ability. These multifunctional characteristics, combining structural integrity, rapid self-repair, surgical-grade adhesion, antimicrobial protection, hemocompatibility, and cytocompatibility, establish this IPN hydrogel as a promising candidate for biomedical adhesives.

Sulfonated polyetheretherketone enriched with MXene V2C promotes bone formation via WNT/β-catenin signaling in bone marrow mesenchymal stem cells

Prosthetic loosening represents a catastrophic postoperative complication in artificial joint replacement, resulting in severe patient morbidity and substantial healthcare costs. This investigation aimed to develop a novel strategy for preventing prosthetic loosening. Two-dimensional MXene V2C nanosheets were synthesized and subsequently immobilized onto three-dimensional porous sulfonated polyetheretherketone (SPEEK) surfaces with polydopamine (PDA) to form V2C-PDA@SPEEK (Abbrev. V2C-PS). The biocompatibility was systematically evaluated using rat bone marrow mesenchymal stem cells (rBMSCs) and murine models. The osteogenic differentiation potential of V2C-PS was assessed through real-time PCR analysis, Alkaline phosphatase (ALP) staining, and Alizarin Red staining. The in vivo osteogenic capacity of V2C-PS surrounding the implant material was evaluated in rat femoral models using micro-CT analysis, biomechanical pull-out testing, sequential fluorescent labeling of newly formed bone, and Van Gieson staining. The molecular mechanisms underlying V2C-PS -mediated osteogenic differentiation of rBMSCs were investigated both in vitro and in vivo using chemical inhibitors, β-catenin shRNA lentiviral silencing, and β-catenin mRNA lentiviral overexpression. The results demonstrated that V2C-PS exhibited excellent biocompatibility. Quantitative analysis revealed substantial upregulation (p < 0.05) of critical osteogenic markers, including RUNX2 (4.4-fold), COL-1 (5.7-fold), OCN (3.3-fold), BMP-2 (4.4-fold), OPN (3.1-fold), BSP (3.3-fold), ON (4.3-fold), and OSX (2.83-fold), in the 25V2C-PS treatment group compared to PS group. The bone parameters were also remarkably enhanced in the 25V2C-PS group (BMD increased by 241 %, bone-implant contact by 159 %, BV/TV by 225 %, Tb.N by 281 %, Tb.Th by 214 %, maximum pull-out force by 250 %, and Tp.Sp decreased by 33 %). Furthermore, V2C-PS were found to enhance rBMSC osteogenic differentiation through activation of the Wnt/β-catenin signaling pathway. This study presents a promising approach for preventing orthopedic prosthetic loosening and demonstrates significant potential for clinical translation.

Formulation development and characterization of sodium alginate cross-linked films incorporated with polydopamine as light-blocking materials: Application on greening inhibition of whole potato tuber

This study fabricated a composite film based on sodium alginate (SA) and polydopamine (PDA) to prevent the greening of whole potatoes during storage. The physical and optical properties of SA-PDA composite films and their capacity to inhibit the greening of whole potatoes were examined. Findings suggested that the incorporation of PDA significantly strengthened the light absorption capability of the film, decreased light transmittance, and enhanced the opacity and mechanical properties. At a dopamine concentration of 0.95%, the composite film presented the lower oxygen and water vapor permeability while showing the highest tensile strength and elongation at break. The SA-PDA-coated whole potatoes with 0.95% dopamine had a lower chlorophyll content (TC), compared with the control and other coated groups after 48 h of storage. Furthermore, the SA-PDA-coated whole potatoes had a significantly lower TC than control and SA groups did at 60 days of storage, along with superior appearance quality.

A bacterial cellulose-polydopamine based injectable hydrogel for enhanced hemostasis in acute wounds

An injectable hydrogel hemostat composed of bacterial cellulose (BC), polydopamine and carboxymethyl cellulose (CMC) is presented as a biocompatible alternative to generally cytotoxic commercial hemostats. In this system, polydopamine (PDA) was coated on BC fibers by in situ oxidative polymerization, and CMC was added to improve matrix injectability, as confirmed by rheological analysis showing shear thinning behavior. The composite was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) to assess its physical, chemical and topographical characteristics. In vitro blood clotting tests demonstrated favorable blood clotting activity, achieving hemostasis within three minutes of application. PDA's antioxidative properties additionally helped to scavenge reactive oxygen species (ROS). The composite was tested for its compatibility with blood and mammalian cells using the in vitro hemolysis assay, cell viability assay, and scratch assay. In vivo studies using rat tail amputation and liver puncture models exhibited effective hemostasis without significant toxicity. Histological analysis of skin tissue (H&E and TNF-α staining) validated the biocompatibility of the material. Thus, the BC/PDA/CMC hydrogel is a promising candidate for rapid hemostasis and wound healing, particularly in deep and irregular wounds.

Horseradish Peroxidase-Triggered Polydopamine-Modified Chitosan Hydrogels for Electrically Programmed and Infrared-Decodable Dynamic Information Storage

The exceptional multiple responsiveness of hydrogels has garnered significant attention for their potential in storing dynamic information. Self-erasing information observable by the naked eye provides an alternative method for data security. Herein, we report a polydopamine (PDA)-modified chitosan (CS) hydrogel that automatically reveals information without external stimuli. Information is embedded in a CS hydrogel containing horseradish peroxidase through an electrical writing process, creating localized high pH regions that trigger rapid enzymatic polymerization of dopamine (DA) into dark PDA. However, unwritten regions experience slower self-oxidation kinetics in air. This mismatched DA oxidation leads to information revelation and time-dependent erasure. The information lifetime can be precisely regulated by the number of electrical writing cycles and the magnitude of the electric current, enabling complex information decryption and allowing for the recognition of valid and invalid signals. These results offer valuable insights into fabricating and applying patterned hydrogels for information storage.

Direct Surface Modification of the Epidermis Using Mussel-Inspired Polydopamine with Multiple Anti-Biofouling Functions

The surface properties of the epidermis are crucial in pathogen adhesion and proliferation. Moreover, damage to the epidermis caused by various physical and chemical attacks provides a favorable environment for pathogen penetration and proliferation through the exposed internal living tissue. Surface modification of the epidermis to impart anti-biofouling properties can provide effective protection against infections. In this study, a facile method of imparting multiple anti-biofouling functions by directly modifying the epidermal surface of an organism using dopamine, which is a mussel-inspired substance, is introduced. Biocompatible polydopamine (PDA) is uniformly applied to organic surfaces with diverse morphological features and surface energies, indicating its versatility. In addition, the reliability of epidermal modification with PDA is confirmed via the PDA-induced prevention of chronic changes in the impedance of the epidermis. Critically, the PDA-modified epidermis exhibited various anti-biofouling functions, including antibacterial and anti-adsorption properties against bacteria and cellular/noncellular microorganisms, respectively. Improved antibacterial properties are successfully realized via integration with tobramycin, which is a representative antibiotic. Direct surface modification using PDA offers an innovative approach to safeguard biological surfaces, particularly the human epidermis, against various pathogens, with potential for application in medical patches and skin-attached devices.

Mussel-Inspired Molecular Strategies for Fabricating Functional Materials With Underwater Adhesion and Self-Healing Properties

The exceptional underwater adhesion and self-healing capabilities of mussels have fascinated researchers for over two decades. Extensive studies have shown that these remarkable properties arise from a series of reversible and dynamic molecular interactions involving mussel foot proteins. Inspired by these molecular interaction strategies, numerous functional materials exhibiting strong underwater adhesion and self-healing performance have been successfully developed. This review systematically explores the nanomechanical mechanisms of mussel-inspired molecular interactions, mainly revealed by direct force measurement techniques such as surface forces apparatus and atomic force microscopy. The development of functional materials, including coacervates, coatings, and hydrogels, with underwater adhesion and self-healing properties, is then summarized. Furthermore, the macroscopic material performances are correlated with the underlying molecular mechanisms, providing valuable insights for the rational design of next-generation mussel-inspired functional materials with enhanced underwater adhesion and self-healing properties.

Dual-step photo-induced self-assembled hydrogel for endogenous oral mucosal wound healing

By introducing piezoelectric materials into hydrogel oral dressings, a microelectric field could be generated under stress stimulation, thus facilitating oral wound healing. However, to adapt to the moist and dynamic environment of the oral cavity, traditional "step-by-step" synthesis often requires the combination of materials with different functionalities. Given the property differences between these materials, this strategy typically involves complex experimental procedures and unnecessary energy consumption. In this study, with the concept of "integrated construction", we innovatively proposed a dual-step photo-induced method and successfully fabricated composite hydrogels with excellent performance. We introduced abundant oxygen vacancies into ZnO, leveraging the enhanced interface dynamics to achieve sustained photo-induced effect. With a double-network polymer framework as a template, this method could achieve the photo-induced spontaneous in-situ synthesis of polydopamine (PDA) within hydrogel without any extra special experimental conditions and complex operation procedures. We conducted a thorough analysis of the mechanism underlying this photo-induced method and applied the as-prepared hydrogel for the treatment of oral wounds, which significantly accelerated the healing process due to the outstanding comprehensive performance of hydrogel. These results suggest novel ideas and theoretical support for the facile construction of high-performance hydrogels based on photodynamic principles, demonstrating immense potential for future applications in wound dressings.

A cost-effective vessel-on-a-chip for high shear stress applications in vascular biology

The vascular endothelium is constantly subjected to hemodynamic forces, including tangential shear stress, which are crucial for maintaining vascular homeostasis. Pathological shear stress levels, such as those observed in pulmonary arterial hypertension (PAH) or atherosclerosis, disrupt this balance, driving vascular remodeling and endothelial dysfunction. Current microfluidic platforms for studying these conditions are limited by high costs, excessive reagent requirements, and non-physiological channel geometries. Here we introduce a novel microfluidic chip system, a Nylon Vessel-on-a-Chip (NVoC) which represents a cost-effective and straightforward fabrication platform that eliminates the need for specialized equipment and enables a physiologically relevant round channel geometry. The NVoC was fabricated using Polydimethylsiloxane (PDMS) and nylon threads, with surface activation achieved through polydopamine and collagen-I coating, enabling robust endothelial cell (EC) attachment and long-term culture. Immortalized endothelial colony-forming cells (iECFCs) and human umbilical vein EC (HUVECs) were used to optimize and validate the platform, demonstrating its compatibility with high shear stress conditions (up to 90 dyne/cm2) and various molecular biology techniques, including RT-qPCR, Western blotting, and immunofluorescent staining. With fabrication costs six times lower than commercial alternatives and overall experimental costs reduced threefold, the NVoC offers the ability to expose endothelial cells to physiological and pathological shear stress levels in a reproducible, accessible, and scalable manner. Its versatility and affordability make it a valuable tool for investigating shear stress-related mechanisms in microvascular diseases, particularly PAH, with potential applications in drug discovery and translational research.

Highly Compatible Nanocomposite-Based Bacterial Cellulose Doped With Dopamine and Titanium Dioxide Nanoparticles: Study the Effect of Mode of Addition, Characterization, Antibacterial, and Wound Healing Efficiencies

Microbial resistance is an expenditure for a country's economy as a whole as well as its health systems. Metal oxide nanoparticles play a role in overcoming microbial resistance to antibiotics. Bacterial cellulose (BC) is a biopolymer that is friendly to the environment and has a wide range of economic uses, particularly in biomedicine. This work deals with the formulation of BC-doped titanium dioxide nanoparticles (TiO2NPs) and polydopamine (DOP), which are presented with antimicrobial activity. Additionally, the mode of addition of the doped materials was studied using physicochemical analysis, including Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD). Moreover, the topographical study used scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The antimicrobial activity was studied and showed the efficiency of the BC/DOP/TiO2NP composite against Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa, Escherichia coli) strains. Additionally, the wound healing was examined on rats that had been purposely wounded. The results observed that the mode of addition contributed to the molecular structure of the formulated BC-doped samples according to the physicochemical and topographical analysis. Moreover, the BC/DOP/TiO2NP composite enhanced wound healing for about 95% closure by Day 14 compared to 50% in the control group. Based on the results, we can suggest BC/DOP/TiO2NP as an excellent candidate for wound dressings.

Effect of DNA Aptamer Concentration on the Stability of PDA Nanoparticle-based Electrochemical Biosensor to Detect Glycated Albumin

BACKGROUND/AIM

The glycated albumin (GA), a potential biomarker for monitoring diabetes mellitus, reflects short-term glycemia and is not influenced by conditions that falsely alter hemoglobin A1c (HbA1c) levels. This study presents a comprehensive evaluation of DNA aptamer-functionalized polydopamine nanoparticles (PDA NPs) for developing a stable biosensor targeting GA.

MATERIALS AND METHODS

DNA aptamers, conjugated to PDA NPs at varying aptamer concentrations (0.05, 0.5, and 5 μM), were systematically analyzed to understand their impact on the morphological, electrochemical behavior, and stable responses of the biosensor.

RESULTS

Morphological assessments using transmission electron microscopy, scanning electron microscopy, and atomic force microscopy confirmed the stability of PDA NPs after conjugation with aptamers. Electrochemical characterization demonstrated enhanced electron transfer efficiency at an optimal aptamer concentration (0.5 μM) for GA detection while stability testing over 30 days indicated sustained sensor functionality.

CONCLUSION

The PDA-0.5 μM aptamer conjugations balance structural integrity, and stability, emphasizing the importance of aptamer concentration optimization for practical biosensor applications.

Melanin-Inspired Maleimide Coatings on Various Substrates for Rapid Thiol Functionalization

In this study, a substrate-independent maleimide film is developed that can be formed under mild aqueous conditions (pH 7.4), and which allows rapid and efficient external thiol immobilization onto the coated surfaces. For the coating block, tyrosine-conjugated maleimide (Tyr-Mal) containing a phenolic amine moiety is prepared as a substrate-independent dormant coating precursor, wherein the maleimide component permits a rapid Michael addition reaction with the thiol moiety of interest. By mimicking natural melanogenesis, Tyr-Mal acts as a substrate for tyrosinase under physiological conditions (pH 7.4) to form a melanin-inspired maleimide (Mel-Mal) film on various substrates, including living cell surfaces. The resulting film undergoes a rapid surface reaction (< 30 min) with external thiol groups under mild aqueous conditions. Considering that a typical polydopamine film requires a long reaction time (≈3 h) under alkaline conditions (pH 8.5) to achieve thiol functionalization with low efficiency, the current surface platform demonstrates significant improvements in terms of its reaction kinetics and usability. Moreover, considering that thiol functionalization and surface coating are performed under mild aqueous conditions, it is expected that the developed Mel-Mal film will be a useful tool in the fields of cell surface engineering, microarrays, and high-throughput screening.

Tunable silver nanostructure-enabled cascaded "One-to-Many" signal amplification platform for accurate capture and ultrasensitive profiling of circulating tumor cells

The sensitive and convenient detection of cancer biomarkers is crucial for early cancer diagnosis. Circulating tumor cells (CTCs) offer valuable insights for monitoring and prognosing breast cancer, yet their effective separation and detection remain challenging. Herein, we present a dual signal amplification platform utilizing size-adjustable silver nanoparticles (Ag NPs) and magnetic capture probe (Fe3O4@PDA) for the selective capture and quantitative detection of CTCs. By carefully selecting and immobilizing aptamer sequences on the surfaces of Fe3O4@PDA and Ag NPs, we achieve co-localization with CTCs through high-affinity interactions. This magnetic separation enables effective isolation of CTCs while addressing complex matrix interference. Furthermore, leveraging a "One-to-Many" strategy with Ag NPs in combination with a urease catalysis system significantly enhanced the sensitivity of our detection platform. We also investigate the impact of Ag NPs size on sensitivity, successfully constructing a colorimetric sensing platform with optimal sensitivity using size-adjustable Ag NPs, achieving a detection limit of 2 cells/mL and a dynamic range of 10 to 5 × 104 cells/mL (R2 = 0.990). This capability enables direct detection of cancer cells in real human blood samples at remarkably low levels. The recovery rates in whole blood ranged from 92 % to 105 %, with relative standard deviations (RSDs) of the recoveries ranging from 3.5 to 8.7 %. Consequently, this research provides innovative approaches for clinical cancer biomarker applications and expands methods for cancer monitoring.

Bioinspired Suction-Driven Strategies with Nanoscale Skin-Controllable Adhesive Architectures for Efficient Liquid Formulated Transdermal Patches

For highly efficient and precise drug release, transdermal drug delivery systems (TDDS) have recently evolved through the combination of intelligent material-based structures with various active components. These strategies are an effort to overcome the significant difficulties in delivering large molecule drugs and nanomaterials due to the physical barrier of the skin, especially the stratum corneum, in traditional TDDS. Interestingly, multiscale suction-driven architectures (SDAs) inspired by bioinspired suction adhesion mechanisms have provided innovative solutions to these challenges. These architectures employ negative pressure to enhance nanoscale skin-controllable skin adhesion, temporarily bypass the skin barrier, and facilitate deep penetration of therapeutic agents, thereby, achieving the goals of increasing drug delivery efficiency and maximizing user convenience as a minimal invasive, needle-free platform. This review provides a comprehensive overview of suction-driven transdermal patches and emphasizes their integration with multifunctional materials to achieve stable adhesion and controlled drug release. Next, we present cost-effective and user-friendly suction-driven drug delivery patch devices through optimization of cupping structures without the incorporation of additional devices. Furthermore, we present cost-effective and user-friendly transdermal drug delivery patch devices that optimize multiscale cupping architectures without the need for additional devices. Potential of bioinspired SDAs in localized and systemic drug delivery through challenging and complex skin, as well as future perspectives, are discussed, along with innovative directions for more efficient and patient-centric transdermal drug delivery solutions.

Rapid and simple on-site salmonella detection in food via direct sample loading using a lipopolysaccharide-imprinted polymer

Salmonella is a major foodborne pathogen that causes salmonellosis, which is characterized by symptoms such as diarrhea, fever, and abdominal cramps. Existing methods for detecting Salmonella, such as culture plating, ELISA, and PCR, are accurate but time-consuming and unsuitable for on-site applications. In this study, we developed a rapid and sensitive electrochemical sensor using a molecularly imprinted polymer (MIP) to detect Salmonella typhimurium (S. typhimurium) by targeting lipopolysaccharides (LPS). Polydopamine (PDA) was used as the polymer matrix because of its cost-efficiency and functional versatility. The sensor demonstrated high sensitivity and selectivity, with a detection limit of 10 CFU/mL and a linear response over the 10²-10⁸ CFU/mL range. The specificity of the sensor was validated against other gram-positive and gram-negative bacteria and showed no significant cross-reactivity. Furthermore, the sensor performed effectively in real food samples, including tap water, milk, and pork, without complex preprocessing. These results highlight the potential of the LPS-imprinted MIP sensor for practical on-site detection of S. typhimurium, improving food safety monitoring and preventing outbreaks in food-handling environments.

Antithrombotic coating with sheltered positive charges prevents contact activation by controlling factor XII-biointerface binding

Antithrombotic surfaces that prevent coagulation activation without interfering with haemostasis are required for blood-contacting devices. Such materials would restrain device-induced thrombogenesis and decrease the need for anticoagulant use, thereby reducing unwanted bleeding. Here, by optimizing the interactions with coagulation factor XII rather than preventing its surface adsorption, we develop a substrate-independent antithrombotic polymeric coating with sheltered positive charges. The antithrombic properties of the coating were demonstrated in vitro with human blood and in vivo using a carotid artery-jugular vein shunt model in rabbits. The coating exhibits a strong interaction with factor XII, but results in a low reciprocal activation of the contact pathway that triggers clot formation. These findings contradict the prevailing strategy of designing antithrombotic materials through protein-repelling surfaces. Overall, the polymeric coating we describe can benefit most blood-contacting devices and is a useful engineering guideline for designing surfaces with improved antithrombotic properties.

Surface functionalization of microscaffolds produced by high-resolution 3D printing: A new layer of freedom

Scaffolded-spheroids represent novel building blocks for bottom-up tissue assembly, allowing to produce constructs with high initial cell density. Previously, we demonstrated the successful differentiation of such building blocks, produced from immortalized human adipose-derived stem cells, towards different phenotypes, and the possibility of creating macro-sized tissue-like constructs in vitro. The culture of cells in vitro depends on the supply of various nutrients and biomolecules, such as growth factors, usually supplemented in the culture medium. Another means for growth factor delivery (in vitro and in vivo) is the release from the scaffold to alter the biological response of surrounding cells (e.g. by release of VEGF).1 As a proof of concept for this approach, we sought to biofunctionalize the surface of the microscaffolds with heparin as a "universal linker" that would allow binding a variety of growth factors/biomolecules. An aminolysis step in an organic solvent made it possible to generate a hydrophilic and charged surface. The backbone of the amine, as well as reaction conditions, led to an adjustable surface modification. The amount of heparin on the surface was increased with an ethylene glycol-based diamine backbone and varied between 8 and 40 ng per microscaffold. Choosing a suitable linker allows easy adjustment of the loading of VEGF and other heparin-binding proteins. Initial results indicated that up to 5 ng VEGF could be loaded per microscaffold, generating a steady VEGF release for 16 days. We report an easy-to-perform, scalable surface modification approach of polyester-based resin that leads to adjustable surface concentrations of heparin. The successful surface aminolysis opens the route to various modifications and broadens the spectrum of biomolecules which can be delivered.

Bioelectronics hydrogels for implantable cardiac and brain disease medical treatment application

Hydrogel-based bioelectronic systems offer significant benefits for point-of-care diagnosis, treatment of cardiac and cerebral disease, surgical procedures, and other medical applications, ushering in a new era of advancements in medical technology. Progress in hydrogel-based bioelectronics has advanced from basic instrument and sensing capabilities to sophisticated multimodal perceptions and feedback systems. Addressing challenges related to immune responses and inflammation regulation after implantation, physiological dynamic mechanism, biological toxicology as well as device size, power consumption, stability, and signal conversion is crucial for the practical implementation of hydrogel-based bioelectronics in medical implants. Therefore, further exploration of hydrogel-based bioelectronics is imperative, and a comprehensive review is necessary to steer the development of these technologies for use in implantable therapies for cardiac and brain/neural conditions. In this review, a concise overview is provided on the fundamental principles underlying ionic electronic and ionic bioelectronic mechanisms. Additionally, a comprehensive examination is conducted on various bioelectronic materials integrated within hydrogels for applications in implantable medical treatments. The analysis encompasses a detailed discussion on the representative structures and physical attributes of hydrogels. This includes an exploration of their intrinsic properties such as mechanical strength, dynamic capabilities, shape-memory features, stability, stretchability, and water retention characteristics. Moreover, the discussion extends to properties related to interactions with tissues or the environment, such as adhesiveness, responsiveness, and degradability. The intricate relationships between the structure and properties of hydrogels are thoroughly examined, along with an elucidation of how these properties influence their applications in implantable medical treatments. The review also delves into the processing techniques and characterization methods employed for hydrogels. Furthermore, recent breakthroughs in the applications of hydrogels are logically explored, covering aspects such as materials, structure, properties, functions, fabrication procedures, and hybridization with other materials. Finally, the review concludes by outlining the future prospects and challenges associated with hydrogels-based bioelectronics systems.

Immobilization of Antibacterial Chlorhexidine on Biodegradable Polycaprolactone/Estradiol Electrospun Nanofibrous Membrane for Bone Regeneration

Membrane-based scaffold for bone regeneration is vastly being explored to address issues that persist in defective bone regeneration, associated with infection and inflammation. This study focused on incorporating estradiol (E2) into biodegradable polycaprolactone (PCL) electrospun nanofibrous membrane, followed by the immobilization with antibacterial chlorhexidine (CHX) through the aid of a polydopamine (PDA) grafting layer. Several analyses including field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), wettability, biodegradation, drug release, antibacterial, and cytotoxicity analyses were conducted to study the physicochemical and biological properties of the membranes. The nanofibers were constructed with an average diameter of 1.32-1.33 μm and a porosity of 51%-53%, which is accommodating bone regeneration. The grafting of PDA was not only able to improve the surface wettability, which in turn allowed controllable degradability and sustained the release of E2 and CHX from the nanofibrous membranes. The immobilization of CHX on the PCL/E2 nanofibers has greatly retarded Gram-negative Escherichia coli compared to Gram-positive Staphylococcus aureus. The in vitro cytotoxicity assay statistically depicted the ability of the fabricated nanofibrous membranes to support cell proliferation without cytotoxic effects at the cell viability above 70%. These cumulative results indicate the potential development of CHX-immobilized PCL/E2 membrane as an alternative strategy to resolve bone regeneration issues.

Supramolecular self-assembly of high-loaded horseradish peroxidase and biorecognized antibody into Au/polydopamine nanocomposites for sensitive immunoassay of Escherichia coli O157:H7 in milk

There is an urgent need for a rapid and sensitive method for the detection of Escherichia coli O157:H7, a class of hazardous foodborne pathogens in food safety. The traditional ELISA, a dominant rapid detection technique, has the disadvantage of low test sensitivity due to the insufficient enzyme loading capacity. In this study, we successfully synthesized self-assembled Au/polydopamine (PDA)/horseradish peroxide (HRP) nanocomposites with high enzyme loading on the outer surface and in the inner space. The high catalytic activity of Au/PDA/HRP was maintained by virtue of its hyperbranched flexible structure. For E. coli O157:H7 detection in milk samples, the proposed immunoassay achieved a visual cut-off value of 103 cfu mL-1 and a low limit of detection of 2.8 × 102 cfu mL-1, which are 33 and 46 times more sensitive than the traditional ELISA, respectively. The tremendous advantages of high sensitivity, excellent specificity, and adequate recovery make it promising for monitoring various kinds of pathogenic bacteria in food safety with greater sensitivity.

Antimicrobial and anti-inflammatory effects of polyethyleneimine-modified polydopamine nanoparticles on a burn-injured skin model

Chronic infections involving bacterial biofilms pose significant treatment challenges due to the resilience of biofilms against existing antimicrobials. Here, we introduce a nanomaterial-based platform for treating Staphylococcus epidermidis biofilms, both in isolation and within a biofilm-infected burn skin model. Our approach leverages biocompatible and photothermal polydopamine nanoparticles (PDNP), functionalized with branched polyethyleneimine (PEI) and loaded with the antibiotic rifampicin, to target bacteria dwelling within biofilms. A key innovation of our method is its ability to not only target planktonic S. epidermidis but also effectively tackle biofilm-embedded bacteria. We demonstrated that PDNP-PEI interacts effectively with the bacterial surface, facilitating laser-activated photothermal eradication of planktonic S. epidermidis. In a 3D skin burn injury model, PDNP-PEI demonstrates anti-inflammatory and reactive oxygen species (ROS)-scavenging effects, reducing inflammatory cytokine levels and promoting healing. The rifampicin-loaded PDNP-PEI (PDNP-PEI-Rif) platform further shows significant efficacy against bacteria inside biofilms. The PDNP-PEI-Rif retained its immunomodulatory activity and efficiently eradicated biofilms grown on our burn-injured 3D skin model, effectively addressing the challenges of biofilm-related infections. This achievement marks a significant advancement in infection management, with the potential for a transformative impact on clinical practice.

Unexplored Mechanisms of Photoprotection: Synergistic Light Absorption and Antioxidant Activity of Melanin

Light exposure has relevant effects both on living organisms and artificial materials. In particular, ultraviolet radiation is known to kill living cells and damage human skin but also degrade important artificial materials like plastics. In nature, the main pigment responsible for photoprotection is melanin, which is able both to prevent penetration of light by absorption and scattering and to block the action of light-generated radicals thanks to its antioxidant properties. The combination of light extinction with antioxidant action is still the most diffused and effective approach to photoprotection. Nevertheless, up to now, these two mechanisms, light extinction and antioxidant activity, have been considered independent. Recent studies showed that exposing melanin to light leads to an increase in its radical content and possibly in its antioxidant activity. Do light extinction and antioxidant activity work in synergy for photoprotection in nature? In this paper, we discuss the steps still needed to answer this intriguing question.

Biological Augmentation Using Electrospun Constructs with Dual Growth Factor Release for Rotator Cuff Repair

Surgical reattachment of tendon to bone is the standard therapy for rotator cuff tear (RCT), but its effectiveness is compromised by retear rates of up to 94%, primarily due to challenges in achieving successful tendon-bone enthesis regeneration under natural conditions. Biological augmentation using biomaterials has emerged as a promising approach to address this challenge. In this study, a bilayer construct incorporates polydopamine (PDA)-mediated bone morphogenetic protein 2 (BMP2) and BMP12 in separate poly(lactic-co-glycolic acid) (PLGA) fiber layers to promote osteoblast and tenocyte growth, respectively, and intermediate fibrocartilage formation, aiming to enhance the regenerative potential of tendon-bone interfaces. The lower layer, consisting of PLGA fibers with BMP2 immobilization through PDA adsorption, significantly accelerated osteoblast growth. Concurrently, the upper BMP12@PLGA-PDA fiber mat facilitated fibrocartilage formation and tendon tissue regeneration, evidenced by significantly elevated tenocyte viability and tenogenic differentiation markers. Therapeutic efficacy assessed through in vivo RCT models demonstrated that the dual-BMP construct augmentation significantly promoted the healing of tendon-bone interfaces, confirmed by biomechanical testing, cartilage immunohistochemistry analysis, and collagen I/II immunohistochemistry analysis. Overall, this combinational strategy, which combines augmentation patches with the controlled release of dual growth factors, shows great promise in improving the overall success rates of rotator cuff repairs.

Polydopamine-mediated gold nanoparticle coating strategy and its application in photothermal polymerase chain reaction

Materials with high light-to-heat conversion efficiencies offer valuable strategies for remote heating. These materials find wide applications in photothermal therapy, water distillation, and gene delivery. In this study, we investigated a universal coating method to impart photothermal features to various surfaces. Polydopamine, a well-known adhesive material inspired by mussels, served as an intermediate layer to anchor polyethyleneimine and capture gold nanoparticles. Subsequently, the coated surface underwent electroless gold deposition to improve photothermal heating efficiency by increasing light absorption. This process was analyzed through scanning electron microscopic imaging and absorbance measurements. To demonstrate functionality, the coated surface was photothermally heated using a light-emitting diode controlled with a microprocessor, targeting the metal regulatory transcription factor 1 gene-a marker for osteoarthritis-and the S gene of the severe fever with thrombocytopenia syndrome virus. Successful amplification of the target genes was confirmed after 34 polymerase chain reaction cycles in just 12 min, verified by gel electrophoresis, demonstrating its diagnostic applicability. Overall, this simple photothermal coating method provides versatile utility, and is applicable to diverse surfaces such as membranes, tissue culture dishes, and microfluidic systems.

Recombinant collagen microneedles for transdermal delivery of antibacterial copper-DNA nanoparticles to treat skin and soft tissue infections

Skin and soft tissue infections (SSTI) include bacterial infections of the skin, muscles, and connective tissue such as ligaments and tendons. SSTI in patients with immunocompromising diseases may lead to chronic, hard-to-heal infected wounds, resulting in disability, amputation, or even death. To treat SSTI and rebuild the defensive barrier of the skin, here we utilize recombinant type XVII collagen protein (rCol XVII) to construct biodegradable, regenerative collagen microneedles (rCol-MNs) for transdermal delivery of antibacterial agents. Spheroidal copper-DNA antibacterial nanoparticles (Cu-CpG NPs; CpG represents short single-stranded synthetic DNA molecules of cytosine and guanine) are synthesized with copper ions and CpG oligodeoxynucleotides (ODNs), followed by polydopamine (PDA) coating to obtain Cu-CpG@PDA. Doping Cu-CpG@PDA into rCol-MNs yields Cu-CpG@PDA-loaded rCol-MNs. These microneedles combine the photothermal conversion property of PDA, antibacterial properties of copper ions, innate immune activation of CpG ODNs, and skin regenerating ability of rCol XVII, allowing the treatment of SSTI and also regenerating the damaged skin. In a mouse model, we show that the Cu-CpG@PDA-loaded rCol-MNs rescue skin wound infections, facilitate the orderly deposition of collagen at the wound site, and promote the healing of infected full-thickness wounds without noticeable scar formation. rCol-MNs serve as a transdermal delivery vehicle and, simultaneously, a reservoir of skin-regenerating recombinant collagen, bringing combined benefits of infection control and skin regeneration. SIGNIFICANCE STATEMENT: Treatment of soft tissue infection requires the delivery of antibacterial agents into the soft tissue or dermis while providing a regenerating environment for open wounds. Here, we devise recombinant collagen microneedles (rCol-MNs) to meet both requirements.

Application of polydopamine as antibacterial and anti-inflammatory materials

Polydopamine (PDA), as a material mimicking the adhesive proteins of mussels in nature, has emerged as a strong candidate for developing novel antibacterial and anti-inflammatory materials due to its outstanding biomimetic adhesion, effective photothermal conversion, excellent biocompatibility and antioxidant capabilities. This review discussed in detail the intricate structure and polymerization principles of PDA, elucidated its mechanisms in combating bacterial infections and inflammation, as well as explored the innovative use of PDA-based composite materials for antibacterial and anti-inflammatory applications. By providing an in-depth analysis of PDA's capabilities and future research directions, this review addresses a crucial need for safer, more effective, and controllable antimicrobial and anti-inflammatory strategies, which aim to contribute to the development of advanced materials that can significantly impact public health.

Polydopamine-coated cerium oxide core-shell nanoparticles for efficient and non-damaging chemical-mechanical polishing

Chemical mechanical polishing (CMP) represents one of the most important steps in the manufacturing of integrated circuits, and high surface quality is always required for the CMP processes of shallow trench isolation (STI) structures. Herein, a new series of polydopamine (PDA)-coated cerium oxide core-shell nanoparticles has been developed as efficient and non-damaging abrasives for CMP of SiO2 on the surface of silicon wafers. The composite abrasives with the structure of SiO2@CeO2@PDA have been fabricated in a simple manner and thoroughly characterized using scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The SiO2 core enhances the content of Ce3+ in the abrasives, while the water-soluble PDA layer facilitates the interaction between the abrasives and SiO2 dielectrics. As a result, the wafers polished with SiO2@CeO2@PDA not only achieved a high polishing rate, but also exhibited a high surface quality (Ra = 0.109). This study not only presents a new efficient and non-damaging type of cerium oxide abrasive for CMP, but also highlights the potential of the surface coordination strategy in the fabrication of advanced abrasives for the manufacturing of integrated circuits.

Flexible, stretchable multifunctional silver nanoparticles-decorated cotton textile based on amyloid-like protein aggregation for electrothermal and photothermal dual-driven wearable heater

The design of multifunctional, high-performance wearable heaters utilizing textile substrates has garnered increasing attention, particularly in the development of body temperature and health monitoring devices. However, fabricating these multifunctional wearable heaters while simultaneously ensuring flexibility, air permeability, Joule heating performance, electromagnetic interference (EMI) shielding and antibacterial properties remains a significant challenge. This study utilizes phase transition lysozyme (PTL) film-mediated electroless deposition (ELD) technology to deposit silver nanoparticles (Ag NPs) on the cotton fabrics surface in a mild aqueous solution at room temperature, thereby constructing a wearable heater with long-term stability, high conductivity, and exceptional photothermal properties. The textiles enriched with Ag NPs exhibit remarkable electrothermal and photothermal dual-driven heating capabilities, achieving temperatures exceeding 110 °C within 50s under 2 V, or in merely a few seconds through photothermal conversion. Importantly, these textiles retain the intrinsic flexibility and breathability of the textile substrate. Furthermore, the amyloid-like protein Ag NP integrated textiles demonstrate excellent antibacterial properties, and exhibit a high EMI shielding efficiency of 50 dB within the frequency range of 8.2-12.4 GHz. Therefore, these multifunctional Ag NPs wearable heaters were expected to find applications in areas such as smart wearable clothing and future health management.

Polydopamine-modified sodium alginate hydrogel for microplastics removal: Adsorption performance, characteristics, and kinetics

The potential health hazards of micro/nanoplastics in food have become a significant concern. This study developed a Polydopamine-modified sodium alginate hydrogel (PMSAH) for removing microplastics in daily drinking water. The hydrogel's performance, characteristics, and kinetics for microplastic removal were systematically evaluated. Results demonstrated that the incorporation of polydopamine reduced the hydrogel's surface zeta potential and increased its adsorption capacity for microplastics. PMSAH5 exhibited the highest removal efficiency, reaching approximately 99.6 %. Additionally, polydopamine-modified sodium alginate hydrogel exhibited higher elasticity and thermal stability. The hydrogel successfully adsorbed microplastics, regardless of their size and surface charge. This adsorption was driven by the combined action of multiple forces, resulting in multilayer adsorption. The unique advantages of polydopamine-mediated multi-molecular interactions present a promising and environmentally friendly approach for effective removal of microplastics in daily drinking water.

Polydopamine Assisted Electroless Deposition of Strongly Adhesive NiFe Films for Flexible Spintronics

Cost-effective techniques for depositing durable magnetic thin films are essential for realizing flexible spintronic devices in wearable and soft robotics applications. Here, we introduce a highly scalable electroless deposition technique for coating ferromagnetic Ni80Fe20 thin films onto flexible polyimide and polyethylene terephthalate substrates via a polydopamine intermediate layer. The resultant films demonstrated very good adhesion strength, especially for those on polyimide substrates, which attained the highest ASTM 3359 rating of 5B and exhibited a tensile pull-off strength greater than 5.82 MPa (ASTM D4541). With the assistance of XPS and TEM results, this unusual adhesive strength of NiFe on the polymers can be traced to the formation of primary bonds across the entire coating: (i) covalent bonding between the polymer substrate and polydopamine, (ii) coordinate covalent bonding between catechol groups in polydopamine and palladium ions, and (iii) metallic bonding between palladium and NiFe. By annealing the NiFe-on-polyimide samples at 300 °C-400 °C, the crystallinity of the material was found to improve, which increased the saturation magnetization of NiFe to 1350 emu/cm3 and decreased the coercivity to 20 Oe. Ferromagnetic resonance also showed ∼31% improvement in the film's Gilbert damping constant after annealing at 300 °C. Application of a bending strain increased the squareness ratio by 22% but decreased the saturation magnetization of the annealed film by 18%. These results suggest that the highly adhesive NiFe films on flexible polyimide substrates were of sufficient quality for spintronic devices, although their properties could be improved if the surface roughness could be decreased to that of physically deposited films.

Hyphenation of Affinity Capillary Electrophoresis with Mass Spectrometry for the Study of Ligand-Protein Interactions: n-Methylmorpholine Acetate Buffer and Polydopamine-Based Coating as Key Assets

The direct and precise assessment of ligand-protein interactions under nearly physiological conditions is the core of drug discovery. In this context, affinity capillary electrophoresis (ACE) has become an emerging and reliable approach. The hyphenation of ACE with mass spectrometry (MS) is even more powerful than the classical ACE-UV methodology. It reduces compound identification errors and increases throughput by facilitating the analysis of the mixtures. However, buffers and capillary coatings compatible with mass spectrometry and operating under physiological conditions are very limited. In this paper, n-methylmorpholine acetate buffer and polydopamine-based coating were highlighted as major assets for CE-MS studies involving native proteins. Thanks to its protein desorption property, n-methylmorpholine improved the peak shape of proteins during CE analysis at physiological pH. The polydopamine-based neutral coating developed in this study is simple to prepare and demonstrated high stability at pH 7.4, enabling its use with an MS detector. The combination of these two key elements enabled us to successfully convert our ACE-UV method for coagulation factor XIIa into an ACE-MS approach operating at physiological pH. This study extends the scope of ACE for medicinal chemistry projects.

3D printed polycaprolactone/poly (L-lactide-co-ϵ-caprolactone) composite ureteral stent with biodegradable and antibacterial properties

The clinical application of biodegradable ureteral stents holds significant potential. There is an urgent need to develop new materials for ureteral stents to address the limitations related to performance degradation and antibacterial properties observed in current designs. Here, we developed a Polycaprolactone (PCL)/Poly (L-lactide-co-ϵ-caprolactone) (PLCL) composite ureteral stent by three-dimensional (3D) printing, which exhibits biodegradable and antibacterial properties. Silver nanoparticles (AgNPs) were bonded to the surface of the stent through the polymerization of dopamine (PDA) and coating with type I collagen (Col I). The ureteral stent (PP-PDA-Ag-Col) had a densely spiraled structure and higher hydrophilicity. The release behavior of silver ions from the stent was found to be slow and continuous when coated with AgNPs, which can enable long-term antibacterial effects after being implantedin vivo. Additionally,in vitrodegradation experiments demonstrated that the different ratios of ureteral stents degraded slowly in artificial urine over 6 weeks without compromising functionality. The stent exhibits excellent hemocompatibility and cell compatibility. The subcutaneous implantation experiment in Sprague-Dawley rats showed that the PP-PDA-Ag-Col stent degraded slowlyin vivoand had good biocompatibility. The stent PCL5/PLCL5 was the most promising ureteral stent regarding antibacterial, mechanical properties, and degradation. The novel 3D-printed PP-PDA-Ag-Col stent exhibits biocompatibility for safein vivotransplantation and antibacterial properties that reduce reliance on antibiotics. Additionally, its biodegradability eliminates the need for secondary surgical removal, making it a promising option for the clinical application of ureteral stents.

Polydopamine-functionalized capsules: From design to applications

In recent years, polydopamine (PDA)-functionalized capsules have garnered significant interest from researchers in the field of materials, owing to its remarkable properties of adhesion, biocompatibility, photothermal conversion capabilities, chemical reactivity, and so on. At present, numerous studies have reported various structures and morphologies of PDA-functionalized capsules fabricated via diverse strategies, that have found applications across a broad spectrum of disciplines. However, there are few comprehensive and systematic reviews focusing on various preparation strategies of PDA-functionalized capsules with various structures. This paper systematically reviewed the preparation strategies and related applications of PDA-functionalized capsules. These strategies of PDA-functionalized capsules were discussed in detail from four parts including PDA-functionalized capsules based on hollow PDA, mesoporous PDA (MPDA), directly encapsulating emulsion, and surface modification of capsules. Then the review outlined the applications of PDA-functionalized capsules in biomedicine, energy, textiles, and the environment. Furthermore, this review summarized the current research findings on PDA-functionalized capsules and outlines their future development directions. Overall, we aim for this review to inspire researchers and offer valuable guidance for the synthesis and application of advanced PDA-functionalized capsules.

Synergistic catecholamine and coordination chemistry for enhanced bioactivity and secondary grafting activity of zirconia dental implants

The inherent bioinertness of zirconia (ZrO2) hinders its early bone integration, presenting a significant obstacle to its widespread use in dental implant technologies. Addressing this, we developed a surface coating leveraging the synergistic effects of catecholamine and coordination chemistry inspired by the mussel byssus cuticle. This coating, named PDPA@Sr, is enriched with strontium ions and amine groups, resulting from a simple immersion of polydopamine (PD)-coated ZrO2 in an alkaline strontium chloride and poly(allylamine) (PA) solution. Compared to conventional mussel-inspired PD coatings, PDPA@Sr demonstrates enhanced aesthetic properties and mechanical stability. The continuous release of strontium ions from the coating significantly enhances osteogenesis, while the abundant surface amine groups offer notable antibacterial effects. More importantly, these amine groups also enable a variety of chemical modifications, including electrostatic adsorption, carbodiimide chemistry, Michael addition, Schiff base formation, and click chemistry, thus providing a multifaceted platform for the advanced surface modification of ZrO2 implants.

Polynorepinephrine and polydopamine-bacterial laccase coatings for phenolic amperometric biosensors

The successful fabrication of biosensors is greatly limited by the immobilization of their bioreceptor, thus we propose a facile and reproducible two-step method to modify graphite electrodes with a bacterial laccase, relying on a fast and controllable potentiostatic process to coat graphite surfaces with biomolecule-compatible thin films of polynorepinephrine (ePNE) and polydopamine (ePDA). Both polymers, synthesized with a similar thickness, were functionalized with bacterial laccase, displaying distinct electrochemical transducing behaviours at pH 5.0 and 7.0. ePNE layer enables adequate electron transfer of anionic and cationic species in acidic and neutral media, whereas transduction across ePDA strongly depends on pH and redox probe charge. ePNE stands out by improving the amperometric responses of the biosensing interface towards a phenolic acid (gallic acid) and a flavonoid (catechin), in respect to ePDA. The optimal graphite/ePNE/laccase interface outperforms biosensing interfaces based on fungal laccases at neutral pH, displaying detection sensitivities of 104 and 14.4 µA cm-2 mM-1for gallic acid and catechin, respectively. The fine synthetic control of the ePNE bio-inspired transduction layer and the use of an alkaliphilic bacterial laccase enabled the construction of an amperometric biosensing interface with extended pH range of polyphenols detection present in food products and agro-industrial waste.

Fabrication of Versatile Antifouling Coatings Inspired by Melanogenesis Using a Tyrosine-Conjugated Carboxybetaine Derivative

In this study, we developed zwitterionic surface coatings of carboxybetaine by mimicking natural melanogenesis. We synthesized an unnatural tyrosine-conjugated carboxybetaine (Tyr-CB) that undergoes melanin-like oxidation upon treatment with tyrosinase under various aqueous conditions. The thickness of the resulting poly(Tyr-CB) film was tuned by adjusting the pH during the coating process. The poly(Tyr-CB)-coated surfaces demonstrated excellent antifouling performance against proteins and cells and imparted (super)hydrophilicity to various substrates. Additionally, post-functionalization with external biotin-PEG-thiol was achieved by targeting the oxidized quinone groups within the poly(Tyr-CB) film network. This enabled biospecific binding to streptavidin, while non-specific interactions were suppressed due to the antifouling background. As our one-step antifouling coating method is simple, involves aqueous conditions, and could be generically used to coat various substrates, it can be a versatile and valuable tool for biosensing, high-throughput screening, and cell-surface engineering.

Experimental and Theoretical Analysis of Dopamine Polymerization on the Surface of Cellulose Nanocrystals and Its Reinforcing Properties in Cellulose Acetate Films

The study of natural materials inspires sustainable innovations, with biomimetics excelling in surface modification. Polydopamine (PDA) offers a promising approach for modifying cellulose nanocrystals (CNC), enhancing their compatibility with hydrophobic polymers by improving interfacial adhesion. In this work, the modification of CNC with PDA (CNC@PDA) significantly enhanced the compatibility between the nanocargoes and the cellulose acetate (CA) matrix. The CNC@PDA complex formation was suggested through a combination of FTIR analysis, particle size distribution measurements and ζ-potential analysis. However, the exact mechanism behind dopamine polymerization on the surface of CNC remains a subject of ongoing debate among researchers due to its complexity. This study hypothesized the formation of modified CNC through this process. Furthermore, this study provided a satisfactory investigation of the antimicrobial activity of CNC@PDA in response to bacterial strains (E. coli, P. aeruginosa, S. aureus and L. plantarum) in view of the hypothesis of the possible generation of reactive oxygen species (ROS). Additionally, the incorporation of CNC@PDA CA films was analyzed to assess its effect as a mechanical reinforcement agent. The results showed an improvement in mechanical properties, with the 1% CNC@PDA film exhibiting the best balance between tensile strength and flexibility.

Dose-dependent enhancement of in vitro osteogenic activity on strontium-decorated polyetheretherketone

Polyetheretherketone (PEEK) is widely used in orthopedic and dental implants due to its excellent mechanical properties, chemical stability, and biocompatibility. However, its inherently bioinert nature makes it present weak osteogenic activity, which greatly restricts its clinical adoption. Herein, strontium (Sr) is incorporated onto the surface of PEEK using mussel-inspired polydopamine coating to improve its osteogenic activity. X-ray photoelectron spectroscopy and ion release assay results confirm that different concentrations of Sr are incorporated onto the PEEK substrate surfaces. The strontium-modified PEEK samples show a stable Sr ion release in 35 days of detection. Better results of MC3T3-E1 pre-osteoblasts adhesion, spreading, and proliferation can be observed in strontium-modified PEEK groups, which demonstrates strontium-modified PEEK samples with the improved MC3T3-E1 pre-osteoblasts compatibility. The boosted osteogenic activity of strontium-modified PEEK samples has been demonstrated by the better performed of ALP activity, extracellular matrix mineralization, collagen secretion, and the remarkable up-regulation of ALP, OCN, OPN, Runx2, Col-I, BSP, and OSX of the MC3T3-E1 pre-osteoblasts. Additionally, the strontium-modified PEEK samples exhibit a dose-dependent enhancement of osteoblasts compatibility and osteogenic activity, and the PEEK-Sr10 group shows the best. These findings indicate that strontium-decorated PEEK implants show promising application in orthopedic and dental implants.

Light-/pH-Regulated Spiropyran Smart-Responsive Hydrophilic Separation Platform for the Identification of Serum Glycopeptides from Hepatocellular Carcinoma Patients

Smart-responsive materials have attracted much attention in the enrichment of post-translational modifications of proteins. In this work, for the first time, we developed a smart enrichment strategy (MNPs-l-DOPA/PEI-SP) based on the change in hydrophilic properties of spiropyran under the regulation of light and pH to realize the controllable enrichment and release of intact glycopeptides. The enrichment mechanism and possible binding mechanism were verified by theoretical calculations. The smart enrichment platform based on MNPs-l-DOPA/PEI-SP was used to screen glycoprotein biomarkers for hepatocellular carcinoma (HCC) to evaluate its cancer diagnostic and monitoring performance. A total of 3,864 intact N-glycopeptides containing 166 N-glycoproteins were successfully identified in serum samples of early-stage HCC patients, while 3,266 intact N-glycopeptides containing 193 glycoproteins were identified in normal control (NC) serum samples. This work not only provides new ideas for the efficient enrichment of intact glycopeptides with smart-responsive material, but also broadens the research possibilities for biomarker discovery in HCC serum liquid biopsies.

Functionalization of Emulsion Interfaces: Surface Chemistry Made Liquid

Disperse systems, and emulsions in particular, are currently massively used in fields as varied as food industry, cosmetics, health care and environmentally-friendly materials. To meet increasingly precise needs or targeted applications, these systems need to be endowed with new functionalities at their interfaces, in addition to their composition and structural properties. However, due to the fragility of drops and the low reactivity of their surface, conventional solid surface chemistry cannot be used for such a purpose. Several specific emulsion interface functionalization techniques have thus been developed for targeted systems and applications, but a general framework has yet to be drawn. In this review, we attempt to present these methods in a unified way through the prism of what we may call "liquid surface chemistry". We propose to categorize existing methods into drop-coating strategies, including layer-by-layer techniques and polymer coating, with a particular focus on polydopamine, and emulsifier-carrier approaches involving particles and/or amphiphilic molecules. They are discussed in a transversal way, highlighting the underlying physico-chemical principles and providing a comparative analysis of their advantages, current limitations and potential for improvement. We also propose future directions and opportunities, involving for instance DNA-based programmability or artificial intelligence, which could make liquid surface chemistry more versatile and controlled.

Polydopamine-encapsulated carbon dots to boost analytical performance for microplastics detection in fluorescence mode

A kind of sulfur-doped carbon dots was prepared which were encapsulated with polydopamine (S-CDs@PDA) that has fluorescence response on polyethylene (PE) microplastics (MPs). Modified membranes were constructed using S-CDs@PDA for MP detection. Through heating and vacuum filtration process, yellow emission from the modified membrane appeared because of the combination between S-CDs@PDA and PE MPs. Notably, the fluorescence signal value of PE MPs detected by S-CDs@PDA-modified membrane was 21.3% higher than that of unmodified S-CDs membrane, and the detection efficiency was 8% higher than that of S-CDs membrane. The minimum detection limit for modified membranes was 4 mg. Due to the good adhesion of polydopamine (PDA), S-CDs@PDA-modified membrane was more easily adhered to PE MPs, showing its excellent detection ability. The rapid quantitative detection of PE MPs in 10 min was realized with a linear equation of y = 3081x + 3686.1 in a linear range of 4-14 mg. Such modified membrane exhibited excellent anti-photobleaching using continuous 365-nm excitation and its sensing performance was further confirmed in sea and river water samples. S-CDs@PDA could detect solid MP powders as well as MPs dispersed in liquids. The detection method constructed with a modified glass fiber filter membrane enables rapid identification and quantitative detection of PE MPs without relying on large-scale instrumentation. This study provided research ideas for fluorescent tracing of PE MPs and paved the way for quantitative detection of micron-sized plastics with smaller particle sizes.

Design of innovative and low-cost dopamine-biotin conjugate sensor for the efficient detection of protein and cancer cells

The rapid, precise identification and quantification of specific biomarkers, toxins, or pathogens is currently a key strategy for achieving more efficient diagnoses. Herein a dopamine-biotin monomer was synthetized and oxidized in the presence of hexamethylenediamine, to obtain adhesive coatings based on polydopamine-biotin (PDA-BT) on different materials to be used in targeted molecular therapy. Insight into the structure of the PDA-BT coating was obtained by solid-state 13C NMR spectroscopy acquired, for the first time, directly onto the coating, deposited on alumina spheres. The receptor binding capacity of the PDA-BT coating toward 4-hydroxyazobenzene-2-carboxylic acid/Avidin complex was verified by means of UV-vis spectroscopy. Different deposition cycles of avidin onto the PDA-BT coating by layer-by-layer assembly showed that the film retains its receptor binding capacity for at least eight consecutive cycles. Finally, the feasibility of PDA-BT coating to recognize cell lines with different grade of overexpression of biotin receptors (BR) was investigated by tumor cell capture experiments by using MCF-7 (BR+) and HL-60 (BR-) cell lines. The results show that the developed system can selectively capture MCF-7 cells indicating that it could represent a first approach for the development of future more sophisticated biosensors easily accessible, low cost and recyclable with the dual and rapid detection of both proteins and cells.

Nanodrug-Engineered Exosomes Achieve a Jointly Dual-Pathway Inhibition on Cuproptosis

Cuproptosis, caused by an intracellular overload of copper (Cu) ions and overexpression of ferredoxin 1 (FDX1), is identified for its regulatory role in the skin wound healing process. This study verifies the presence of cuproptosis in skin wound beds and reactive oxygen species-induced cells model. To address the two pathways leading to cell cuproptosis, a nanodrug-engineered exosomes is proposed. A Cu-chelator (Clioquinol, CQ) polydopamine (PDA)-modified stem cell exosome loaded with siRNA-FDX1, named EXOsiFDX1-PDA@CQ, is designed to efficiently inhibit the two cuproptosis pathways. The functionalized exosomes are loaded into an injectable hydrogel and applied to treat diabetic wounds in mice and acute skin wounds in pigs. The local and controlled release of EXOsiFDX1-PDA@CQ ensures the retention of the therapeutic agent at wound beds, effectively promoting wound healing. The strategy of engineered exosomes with functional nanoparticles (NPs) proposed in this study offers an efficient and scalable new approach for regulating cuproptosis.

Novel microfluidic development of pH-responsive hybrid liposomes: In vitro and in vivo assessment for enhanced wound Healing

Wound healing is a complex biological process crucial for tissue repair, especially in chronic wounds where healing is impaired. Liposomes have emerged as promising vehicles for delivering therapeutics to facilitate wound repair. Liposomes have been explored as effective carriers for therapeutic agents. However, traditional methods of liposome preparation face significant challenges, particularly in achieving consistent stability and precise control over drug encapsulation and release. This study addresses these challenges by pioneering the development of Hybrid Liposomes (HLPs) using microfluidic technology, which provides more controlled characteristics through precisely managed formulation parameters. Notably, the formation of Polydopamine (PDA) polymer within HLPs facilitates pH-responsive drug release, making them well-suited for acidic wound environments. Furthermore, surface modification with Folic Acid (FA) enhances cellular interaction with the HLPs. In vitro and in vivo studies demonstrate the efficacy of HLPs loaded with Hyaluronic Acid (HA) or Phenytoin (PHT) in promoting wound healing. Microfluidics optimizes the stability of HLPs over 90 days, underscoring their potential as a potent, antibiotic-free drug delivery system. In conclusion, this research advances the understanding of microfluidic optimization for HLPs, offering cutting-edge drug delivery systems. The transformative potential of targeted HLPs through microfluidics holds promise for revolutionizing wound healing and inspires optimism for effective therapeutic interventions.

Microscale Metal Patterning on Any Substrate: Exploring the Potential of Poly(dopamine) Films in High Resolution, High Contrast, Conformal Lithography

We have explored the potential of poly(dopamine) (PDA) thin films as versatile, high resolution conformal photoresists, using catalytic photoreduction of silver ions to micropattern the film. The combination of photosensitivity, biocompatibilty, and straightforward deposition under mild conditions into thin (∼45 nm) conformal coatings on nearly any material makes PDA films of interest in lithographic patterning on highly nonplanar geometries as well as on soft and biological materials where standard photoresists cannot be used. PDA and poly(norepinephrine) (PNE) films deposited with a standard autoxidation process were investigated along with PDA film deposited with a fast oxidation (FO) technique. Notably, we find that nonspecific deposition of silver off the lithographic pattern is strongly suppressed in PNE and nearly absent in FO-PDA films, which makes very high contrast lithography possible. We attribute this to a lower ratio of catechol to quinone moieties in these films compared to standard PDA films. PNE and FO-PDA films also exhibit smaller silver grain sizes (<40 nm) than standard PDA films, where grains are up to 200 nm in size. We demonstrate laser-scanning lithography patterns at 1.7 μm spatial resolution near the optical resolution limit of the experiment. Continuous silver films can readily be deposited on PDA, PNE, and FO-PDA with blue (λ = 473 nm) and UV-A (375 nm) light, but not with green (515 nm) light. The UV light at lower intensities deposits silver several times faster than the blue light but also degrades the deposited silver at high light intensities. Silver films deposited in this way reach the percolation threshold at optical doses (at λ = 473 nm) in the range of 10-50 kJ/cm2, and SEM images of the films appear nearly pinhole free at comparable doses.

Enhanced osteogenesis and antibacterial activity of dual-functional PEEK implants via biomimetic polydopamine modification with chondroitin sulfate and levofloxacin

Polyetheretherketone (PEEK) implants have emerged as a clinically favored alternative to titanium alloy implants for cranial bone substitutes due to their excellent mechanical properties and biocompatibility. However, the biological inertness of PEEK has hindered its clinical application. To address this issue, we developed a dual-functional surface modification method aimed at enhancing both osteogenesis and antibacterial activity, which was achieved through the sustained release of chondroitin sulfate (CS) and levofloxacin (LVFX) from a biomimetic polydopamine (PDA) coating on the PEEK surface. CS was introduced to promote cell adhesion and osteogenic differentiation. Meanwhile, incorporation of antibiotic LVFX was essential to prevent infections, which are a critical concern in bone defect repairing. To our delight, experiment results demonstrated that the SPKD/CS-LVFX specimen exhibited enhanced hydrophilicity and sustained drug release profiles. Furthermore, in vitro experiments showed that cell growth and adhesion, cell viability, and osteogenic differentiation of mouse calvaria-derived osteoblast precursor (MC3T3-E1) cells were significantly improved on the SPKD/CS-LVFX coating. Antibacterial assays also confirmed that the SPKD/CS-LVFX specimen effectively inhibited the growth of Escherichia coli and Staphylococcus aureus, attributable to the antibiotic LVFX released from the PDA coating. To sum up, this dual-functional PEEK implant showed a promising potential for clinical application in bone defects repairing, providing excellent osteogenic and antibacterial properties through a synergistic approach.

Synthesis and characterization of Fe3O4@SiO2@PDA@Ag core-shell nanoparticles and biological application on human lung cancer cell line and antibacterial strains

Novel magnetic and metallic nanoparticles garner much attention of researchers due to their biological, chemical and catalytic properties in many chemical reactions. In this study, we have successfully prepared a core-shell Fe3O4@SiO2@PDA nanocomposite wrapped with Ag using a simple synthesis method, characterised and tested on small cell lung cancer and antibacterial strains. Incorporating Ag in Fe3O4@SiO2@PDA provides promising advantages in biomedical applications. The magnetic Fe3O4 nanoparticles were coated with SiO2 to obtain negatively charged surface which is then coated with polydopamine (PDA). Then silver nanoparticles were assembled on Fe3O4@SiO2@PDA surface, which results in the formation core-shell nanocomposite. The synthesised nanocomposite were characterized using SEM-EDAX, dynamic light scattering, XRD, FT-IR and TEM. In this work, we report the anticancer activity of silver nanoparticles against H1299 lung cancer cell line using MTT assay. The cytotoxicity data revealed that the IC50 of Fe3O4@SiO2@PDA@Ag against H1299 lung cancer nanocomposites cells was 21.52 µg/mL. Furthermore, the biological data of nanocomposites against Gram-negative 'Pseudomonas aeruginosa' and Gram-positive 'Staphylococcus aureus' were carried out. The range of minimum inhibitory concentration was found to be 115 µg/mL where gentamicin was used as a standard drug. The synthesized AgNPs proves its supremacy as an efficient biomedical agent and AgNPs may act as potential beneficial molecule in lung cancer chemoprevention and antibacterial strains.