Removal of chronic excess phosphates in blood is critical for patients suffering from end-stage renal disease (ESRD). ESRD patients can be treated with peritoneal dialysis (PD), during which phosphates are transported from the blood to a specific solution, named dialysate, introduced into their peritoneal cavity. However, phosphate removal in PD is currently insufficient but could be improved by introducing in dialysate phosphate adsorbents. Iron oxide nanoparticles are biocompatible and well-known effective phosphate adsorbents, but their colloidal stability at physiological pH and adsorption capacity in high ionic strength aqueous media such as dialysate are significant challenges. Here, we have evaluated the potential of tannic acid-coated iron oxide raspberry-shaped nanoclusters (RSNs@TA) for improving phosphate adsorption in dialysate. We have investigated the influence of the TA coating on phosphate adsorption by performing adsorption experiments with uncoated and TA-coated RSNs. In parallel, we have studied the influence of electrolytes and compounds in dialysate on phosphate adsorption by conducting experiments in pH 7 water and dialysate. The TA coating was shown to provide a high colloidal stability to the nanoclusters and mitigates the inhibitory effect of electrolytes in dialysate on phosphate adsorption. Indeed, electrolytes in dialysate decreased the phosphate adsorption on both nanoclusters but especially on uncoated ones by disturbing phosphate outer-sphere complexes. Thus, RSNs@TA demonstrated enhanced adsorption capacity compared to uncoated RSNs in dialysate (20.7 +/- 6.4 mg P.g-1) and in pH 7 water (26.4 +/- 8.1 mg P.g-1). These results established RSNs@TA as promising adsorbents for phosphate removal in dialysate during a PD process.

Artificial leaves emulate biological leaves by converting photonic energy into chemical energy, yet replicating photosynthetic functionalities at the molecular level remains a challenge. Key limitations of current artificial leaves include (1) recombination in photosensitizers and (2) photooxidation of the photosensitizers, (3) inefficient electron and proton transfer to reaction centers, and (4) limited scalability of the illuminated surface area. Herein, we address these challenges by mimicking the thylakoid membrane, nature's photosynthetic machinery, in a simplified system using an electropolymerized ultrathin polydopamine (PDA) nanosheet embedded with CdSe@CdS nanorods (NRs) as photosensitizers and cobaloximes as hydrogen evolution catalysts. The PDA nanosheet provides essential functions of the thylakoid membrane: it suppresses recombination through rapid electron acceptance, facilitates efficient electron transport, and mitigates photooxidation of photosensitizers within an ultrathin layer, as demonstrated by photoelectrochemical analysis, transient absorption spectroscopy, and scanning electrochemical microscopy. These findings lay the groundwork for designing artificial thylakoid membranes, advancing the development of next-generation materials for efficient energy conversion, and addressing some of the fundamental limitations of current artificial leaf systems.

ABSTRACT Congenital diaphragmatic hernia (CDH) is a rare disease that has been increasing in prevalence since the end of the 20th century. The recurrence rate of hernias is over 50%, increasing morbidity. Research is ongoing to identify a suitable solution to repair large defects because common prosthesis does not match the mechanical properties of the native tissue. This pilot study aims to evaluate a new non‐biodegradable thermoplastic polyurethane elastomer (TPU) bilayer patch. Its mechanical properties may be better suited to facilitate growth from childhood to adulthood. Its structure comprises a fibrous layer that promotes cell colonization and integration, and a smooth film layer that prevents cell adhesion. In vitro studies showed that both fibroblasts and myoblasts colonized the fibrous layers efficiently when they were optimized with an adhesive polydopamine (PDA) film and a collagen I (Coll I) coating. This facilitated early colonization, increased proliferation and cell spreading. New materials, whether functionalized or not, did not induce inflammation. Subsequent in vivo studies in rats showed significant cell integration in TPU patches without prosthetic debris. In contrast, phagocytosed prosthetic debris were detected in rats implanted with the reference material expanded polytetrafluoroethylene (e‐PTFE). These TPU patches appear as promising new implants for the treatment of diaphragmatic hernias.

Melanins are multifunctional biopolymers with unique properties, ranging from UV and radiation protection to antioxidant activity and metal chelation, making them highly attractive for biomedical applications. Despite extensive research, the mechanisms underlying melanin formation remain only partially understood, and access to these biopolymers therefore relies on suitable molecular precursors. While most studies have focused on catecholamine-derived eumelanins such as 3,4-dihydroxyphenylalanine (L-DOPA) and dihydroxyindole (DHI), nitrogen-free precursors such as 1,8-dihydroxynaphthalene (1,8-DHN) are emerging as promising routes to allomelanins. To date, however, these two precursor classes have largely been investigated separately, limiting a broader understanding of structure–function relationships. This review aims to compare electrochemical and redox-based pathways to catecholamine- and DHN-derived materials, emphasizing both their common principles and distinctive features. By bridging these parallel research streams, we propose a methodological framework for guiding future research on melanin-inspired materials and bioelectrochemical technologies.

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 C-13 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 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.

Liquid-liquid phase separation (LLPS) of biomolecules is increasingly studied in bulk conditions mainly because of its expected implication in the emergence of life. However, in living systems, the LLPS occurs also at interfaces through a precise spatiotemporal localization-induction way. Based on enzymatically active nanoarchitectured polyelectrolyte multilayer (PEM) films, a tunable stimuli-responsive surface controlling coacervation processes specifically at the solid-liquid interface is developed. Urease, embedded in multilayers, is used as a trigger to increase locally the pH near the surface in the presence of urea. The deprotonation of a short peptide synthon FFssFF occurs in close vicinity of the surface and induces the formation of FFssFF coacervate droplets at, and in, the vicinity of the surface. The variation of i) the number of enzyme layers in the PEM film, the concentration of ii) urea, or iii) coacervator impacts the kinetic, the size, and the surface density of the droplets which can result in a quasi-full covering of the surface. Based on optical and fluorescence microscopy images using a fluorescently labelled FFssFFK-Bodipy coacervator, a mechanism of the droplet's formation is established explaining the spatial localization and the control of the coacervation process.

This review summarizes recent advances in biomolecule-mediated exfoliation of graphene and related materials, and discusses their emerging applications in dental medicine. Natural biomolecules, including polyphenols, proteins and polysaccharides, are evaluated as exfoliating agents, emphasizing their influence on the structural and biological properties of graphene and related materials. Particular attention is given to how the synthesis methodologies affects physicochemical properties of the resulting materials and, in turn, biological and mechanical properties. The practical relevance of these materials in dentistry is demonstrated through their applications as functional fillers in dental cements, luting agents, endodontic sealers, and restorative composites, as well as advanced protective coatings for dental substrates and devices. Mechanistic insights into how exfoliation-driven structural modifications dictate material performance in specific dental applications are provided. Collectively, the findings highlight that biomolecule-mediated approaches represent a sustainable, scalable, and versatile strategy for engineering graphene-based materials that simultaneously meet functional requirements and biocompatibility standards essential for successful dental applications.

The electrodeposition of different isomers of dihydroxypyridine (DHP) from sodium acetate buffer at pH = 5 was undertaken on amorphous carbon and gold working electrodes using cyclic voltammetry and chronoamperometry. It was found that films can be formed from 2,3-DHP, 2,5-DHP, and 2,6-DHP (about 20 nm thick after 5 potential cycles in CV experiments) but those coatings display different surface properties as their wettability and roughness despite similar chemical composition. In addition, the films prepared at small potential sweep rates from 2,3-DHP and 2,5-DHP contain crystalline domains as inferred from high resolution transmission electron microscopy and selected area electron diffraction. As an isomer-independent property, the films made from 2,3-DHP, 2,5-DHP, and 2,6-DHP all display an anti-oxidant behavior. This study shows that it is possible to easily tune the structure and properties of DHP-based electropolymerized films, the films made from 2,5-DHP being the most promising for future applications.

Xerostomia is frequently associated with an increased risk of oral candidiasis caused by Candida albicans. Despite its high prevalence, current therapeutic options remain limited, with management largely dependent on saliva substitutes for symptomatic relief. Objective This in vitro study aimed to evaluate the effect of various saliva substitutes on Candida albicans biofilm growth. Material and methods Six commercially available saliva substitutes were evaluated using a standardized Candida albicans biofilm growth assay in a 96-well plate format. Experimental conditions were adapted to simulate the oral environment, including the formation of a salivary pellicle. Salivary pellicle formation was characterized by measuring mass deposition and viscoelastic properties, before and after rinsing with saliva substitutes, using Quartz Crystal Microbalance with Dissipation monitoring (QCM-D). Statistical analyses were performed using two-way ANOVA followed by Tukey’s post hoc test for biofilm data, and unpaired Student’s t-test for salivary protein content. Results Two oil-based substitutes (Aequasyal® and Vea Oris®) significantly enhanced Candida albicans biofilm formation compared to control (PBS) (p < 0.05). QCM-D characterization of the salivary pellicle after rinsing revealed that this effect was associated with stable interactions between substitute components and the salivary pellicle, leading to structural modifications of the protein layer. Conclusion While oil-based saliva substitutes effectively alleviate xerostomia symptoms, they may unintentionally promote Candida albicans biofilm formation. Clinicians should exercise caution when recommending these products to patients with a history of oral candidiasis, favoring water-based alternatives especially in high-risk individuals.

Many articles describe the use of enzymes to induce the formation of a supramolecular hydrogel. These enzymes catalyze the transformation of water-soluble precursors, often short peptides, into hydrogelators. The use of non-enzymatic proteins to induce or stabilize peptide self-assembly is a rarely reported phenomenon, which raises fundamental questions: how can a protein induce peptide self-assembly? How is the peptide recognized and how does it, or the peptide assembly, interact with the protein? The heptapeptide Fmoc-GFFYE-NH-(CH2)2-s-s-(CH2)2-NH-CO-(CH2)2-CO-EE-OH, called L-1 (L = natural chiral amino acids), is a water-soluble compound leading to an increasingly viscous solution over time due to the formation of nanofibers, but does not result in hydrogel (at least not within 3 months). When bovine serum albumin (BSA) is added to a freshly prepared solution of L-1, a hydrogel is obtained in less than 10 min. The variation in the L-1/BSA ratio has an impact on the gelation rate and the mechanical properties of the resulting hydrogel. Thus, the protein appears to act as (i) a catalyst and (ii) a cross-linking point. Strikingly, if the enantiomer D-1 (D = unnatural chiral amino acids) is used instead of L-1, the mixture with BSA remains liquid and non-viscous. Similar behavior is also observed for other proteins. Spectroscopic analyses (CD, fluorescence) and electronic microscopy images confirm that the L-1 peptide self-assembles in nanofibers of 10 nm diameter through β-sheet organization, which is not the case for the peptide D-1. A molecular dynamics study shows that BSA is capable of interacting with both enantiomer peptides L-1 and D-1. However, interaction with L-1 tends to unfold the peptide backbone, making the interaction with the protein more stable and promoting the assembly of L-1 peptides. Conversely, the interaction between BSA and D-1 is more dynamic and appears to be less spatially localized on the BSA. Furthermore, in this interaction, the D-1 peptide keeps its globular conformation. These results highlight the impact of a short peptide's chirality on protein-triggered supramolecular hydrogelation.

The deposition of conformal films from redox-active biological molecules, such as catechols, catecholamines, and other polyphenols, has demonstrated great versatility in terms of the substrate used. Precursors of allomelanins, mainly found in plants and fungi, have been largely overlooked as precursors for the design of conformal and robust coatings. Moreover, their potential application for the electrodeposition of films on conductive substrates has not yet been investigated. Here, the electrodeposition by cyclic voltammetry and chronoamperometry of 1,8-dihydroxynaphthalene (1,8-DHN), a precursor of allomelanin, onto gold electrodes and onto Co-Cr alloys from aqueous solution-ethanol mixtures yields films with potential sweep rate tunable thickness and swelling. The resulting films are antioxidants, and the reservoir of antioxidant moieties is not limited to their surface but also extends into the bulk of the film. In addition, the films produced after a limited energy supply (in the potential window -1 to +1 V vs Ag/AgCl) are strongly antimicrobial against two strains of Pseudomonas aeruginosa without further post-deposition treatment. In addition, their mechanical properties allow them to be detached from their substrates as free-standing films, opening avenues for diverse applications in biomedicine, energy storage, catalysis, sensing, and optoelectronics.

Hydrogels are materials in which water is present as the major component in a network of macromolecules, inorganic colloids or low molecular weight organogelators. To tune their viscoelastic properties, they can be crosslinked, making use of their chemical moieties, but most often with cytotoxicity issues. Another approach consists in modifying the intermolecular interactions of the gelator or its interactions with water. In this framework, playing with the nature of the used electrolyte becomes a popular approach. Even if many reports describe the influence of anions or cations in the Hofmeister series on the mechanical properties of hydrogels, very few investigate the possibility of modifying those properties in a reversible manner between two states characteristic of each electrolyte. Herein, it is shown that agar-agar hydrogels prepared in the presence of high ionic strength NaCl or NaSCN display strongly different mechanical properties and that a change in the nature of the electrolyte in the presence of the gel does not significantly change its storage and loss moduli. This lack of reversibility in the time scale of one day or more is shown to be related to the high inaccessibility of the water and ions present in the porous volume after the gel formation.

Dental diseases pose a global health concern. In addition to medication and care, the use of biocompatible and even bioactive dental materials can contribute to global oral health. Among such materials, nanomaterials begin to be used. In this context, the incorporation of graphene-based materials into dental biomaterials could offer advantages such as increased mechanical strength. Nevertheless, biocompatibility issues still hinder their adoption. In this study, a biocomposite of few-layered graphene and tannic acid (FLG–TA) was synthesized through a straightforward, bio-based methodology. Physicochemical characterizations elucidated the structural and morphological attributes of the biocomposite. By incorporating antioxidant TA molecules onto the FLG surface, the biocomposite dynamically mitigated reactive oxygen species, demonstrating no cytotoxicity to periodontal ligament cells up to 200 µg·mL−1 while promoting cellular adhesion and maintaining chromatin integrity. Overall, because of its favorable biocompatibility FLG–TA holds promise as a novel biomaterial for dental applications.

Background: Electrodeposition of functional films from polyphenol-containing solutions has emerged as a new field of surface functionalization from bio-sourced molecules. There is, however, almost no knowledge about the chemical structure of such complex films. It is the aim of this research to use the known electrodeposition of films made from catechol and resorcinol, two isomers of dihydroxybenzene, to understand the electrodeposition of a more complex polyphenol, quercetin, which is constituted from a fused catechol and resorcinol moiety. The aim of this article is hence to introduce some methodology in the interpretation of the electrochemical behavior of complex polyphenols starting from their building blocks. Methods: Cyclic voltammetry (CV) is used to deposit films from quercetin and from equimolar blends of catechol and resorcinol on amorphous carbon and gold working electrodes. The main experimental parameter was the potential sweep rate used during the CVs. Results: The CV of quercetin is not the exact sum of the CV of the catechol + resorcinol blends, but the major features are conserved, namely the presence of two main oxidation peaks affiliated to those of catechol and resorcinol but shifted to less anodic potentials. In addition, the anodic electron transfer coefficients of the two oxidation waves of quercetin are higher than those measured in the catechol resorcinol blend. However, film deposition ability is reduced with quercetin compared to catechol + resorcinol blend in probable relationship to steric hindrance occurring during the non-electrochemical crosslinking of the deposit. The quercetin-based films deposited at 10 mV·s−1 on gold electrodes are conformal and display some antioxidant activity.

Specific ion effects on the structure and function of many biological macromolecules, their associations, colloidal systems, interfacial phenomena, and even “simple” electrolytes solutions are ubiquitous. The molecular origin of such phenomena is discussed either as a salt-induced change of the water structure (the hydrogen bond network) or some specific (solvent mediated) interactions of one or both of the ions of the electrolyte with the investigated co-solute (macromolecules or colloidal particles). The case of hydrogels is of high interest but is only marginally explored with respect to other physico-chemical systems because they are formed through the interactions of gelling agents in the presence of water and the added electrolyte. In addition, hydrogels in a physiological environment, in which they are used for biomedical applications, may be subjected to fluctuations in their ionic environment. In this review, specific ion effects on the properties of hydrogels (made from macromolecules or small-molecular-weight gelators) are reviewed and discussed. In particular, the importance of specific ion binding to the molecules constituting the gel network versus the effect of the same ions on the structure of water is discussed.

The electrodeposition of derivatives of phenol or of other polyphenols by means of cyclic voltammetry or other electrochemical methods offers the opportunity to eliminate rather hazardous molecules from solution and to coat conductive surfaces with robust, conformal and chemically reactive films. Herein electrodeposition of resveratrol, a natural polyphenol of wines, is investigated on amorphous carbon electrodes and compared to the well known electrodeposition of resorcinol from which it derives with the aim to understand the role of basic constituents in the electrochemistry of complex polyphenols. It is shown that the presence of 4-vinylphenol group on resorcinol to yield resveratrol does not hinder the electrode passivation under cyclic voltammetry but at the contrary that the oxidation of resveratrol occurs at lower potentials than the oxidation of resorcinol. The electron transfer coefficient on amorphous carbon is also evaluated and it is shown that resveratrol based coatings, contrarily to resorcinol ones, display an interesting antioxidant activity. All the obtained films were conformal and hydrophilic.

AbstractSucrose and glycerol have gained attention as additives for hydrogels, owing to their capacity to exert considerable influence over the physicochemical, mechanical, and biological characteristics of these materials. Herein, these effects on agarose hydrogels (AHs) are explored. A series of AHs are synthesized using sucrose (30% and 300% w/v) and glycerol as additives. The storage modulus (10.0–13.7 kPa) and hydrophilicity of the hydrogels (contact angle < 50°) do not vary significantly with sucrose or glycerol addition. However, sucrose enhances the hydration capacity of the hydrogels by up to 170%, whereas glycerol reduces it. Interestingly, sucrose and glycerol individually do not have bacteriostatic effects against Staphylococcus epidermidis, but their combination significantly (p ≤ 0.001) inhibits the growth of both S. epidermidis and Pseudomonas aeruginosa by 63% and 29%, respectively, in comparison to native agarose. Cytotoxicity testing on NIH/3T3 murine fibroblasts reveals that sucrose increases cell viability up to 98%, while glycerol reduces it below 60%. Overall, these hydrogels hold promise for antibacterial biomedical applications as wound dressing materials and surface coatings for medical devices and can also be used to formulate bioinks for 3D bioprinting.

Polydopamine coatings have been shown to allow to coat almost all materials with conformal films having a tunable thickness from a few up to more than 100 nm (and even more in some specific cases). These films are able to reduce metal cations, to be modified with many chemical moieties and advent hence as a “Holy Grail” in surface chemistry with an impressive amount of applicative papers published since 2007. However, the broad application field and ease of deposition from aqueous solutions hidden the complexity of the deposition mechanism(s). The discovery that polydopamine (PDA) films also form at air/water interfaces (in the absence of stirring or in stirring dependent manner) to yield membranes with physicochemical properties different than PDA films deposited at solid/water interfaces highlighted for the first time that the nature of the interfaces plays a major role in the PDA film growth mechanism and in the film properties. More recent research allowed to show that the surface chemistry of the used solid substrate modifies the composition of the thin deposited PDA film during the early stages of the deposition process with further deposition yielding to an almost substrate-independent PDA film. It is the aim of this review to describe complex surface effects occurring in PDA deposition and hence to complement other reviews which described the complexity of the chemistry yielding to PDA coatings.