Search Results (108)

Aminotris(methylene phosphonic acid) (ATMP) and poly(acrylic acid) sodium salt (PAA) have shown favorable results in the treatment of porous building materials against weathering damage, showing promising potential as mixed-in additives during the production of lime-based mortars. This study investigates the impact of these additives on microstructure and mechanical properties. Additives were introduced in various concentrations to assess their influence on CaCO₃ crystallization, porosity, strength, and carbonation behavior. Results revealed significant modifications in the morphology of CaCO₃ precipitates, showing evidence of nanostructured CaCO₃ aggregates and vaterite stabilization, thus indicating a non-classical crystallization pathway through the formation of amorphous CaCO₃ phase(s), facilitated by organic occlusions. These nanostructural changes, resembling biomimetic calcitic precipitates enhanced mechanical performance by enabling plastic deformation and intergranular bridging. Increased porosity and pore connectivity facilitated CO₂ diffusion towards the mortar matrix, contributing to strength development over time. However, high additive concentrations resulted in poor mechanical performance due to the excessive air entrainment capabilities of short-length polymers. Overall, this study demonstrates that the optimized dosages of ATMP and PAA can significantly enhance the durability and mechanical performance of lime-based mortars and suggests a promising alternative for the tailored manufacturing of highly compatible and durable materials for both the restoration of cultural heritage and modern sustainable construction. Full article

Plant tendrils exhibit intriguing tropism motions like bending, twisting, and coiling. Herein, we report the application of a liquid crystal elastomer (LCE) to make a light-sensitive and biomimetic coil to replicate behaviors of plant tendrils. The LCE coil consists of diacrylate azobenzene, diacrylate mesogens, and thiol-based spacers. These components are first mixed to form a highly viscous prepolymer solution through a thiol-acrylate Michael addition reaction. Subsequently, an extrusion–rolling process is developed to draw the viscous solution into a coil, which is mechanically stretched in a single direction to align mesogens in the LCE. Finally, the coil is photopolymerized under UV light to form an LCE coil with a diameter of 375 µm. The LCE coil possesses good rigidity and flexibility and shows movement upon light exposure. For example, the LCE coil shows a reversible bending up to 120° to 365 nm UV and 30% contraction to 455 nm visible light, respectively, due to trans-cis photoisomerization of azobenzene derivatives. When the coil is irradiated with UV light with an intensity up to 10 mW cm⁻², it can twist and coil up. It can also wrap around the UV light tube in 6 s, similar to a plant tendril. This type of light-responsive coil has great potential in making biomimetic plants or soft robotics. Full article

Bone tissue engineering aims to restore lost bone and create an environment conducive to new bone formation. To address this challenge, we developed a novel biomimetic hydrogel that combines maleic anhydride–modified type I collagen (ColME) with maleic anhydride–modified demineralized and decellularized porcine bone matrix particles (mDBMp), forming a composite ColME–mDBMp (CMB) hydrogel. Chemical modification of collagen resulted in a high degree of substitution, thereby enhancing its photocrosslinkability. Integration of mDBMp into the ColME hydrogel via photocrosslinking resulted in enhanced physiological stability, reduced shrinkage, and improved mechanical strength compared to gelatin methacrylate (GelMA)-based hydrogels. Moreover, mineralization of the CMB hydrogel promoted the formation of pure hydroxyapatite (HAp) crystals, providing superior stiffness while maintaining ductility relative to GelMA-based hydrogels. In vitro, human bone marrow mesenchymal stem cells (hBMSCs) encapsulated in CMB hydrogels exhibited enhanced proliferation, cell–matrix interactions, and osteogenic differentiation, as evidenced by increased calcium deposition and histological analysis. These results demonstrate that the CMB hydrogel, enriched with extracellular matrix (ECM) components, shows considerable promise over current GelMA-based hydrogels for bone tissue engineering. Full article

Peptide-based biomimetic treatments have gained increased attention in the dental field due to their biocompatibility and minimally invasive qualities. These biomimetic approaches can replicate the native architecture of dental tissues, thus contributing to higher success rates and improved longevity of restorations. The aim of this study was first to examine the biocompatibility and stability of an amelogenin peptide-based chitosan hydrogel (P26-CS) against salivary enzymes. Second, we aimed to evaluate its efficacy in biomimetically repairing human dental lesions in situ. White spot lesions (WSLs) in enamel and non-carious cervical lesions (NCCLs) in dentin were artificially created. Chitosan (CS) improved peptide stability, while remineralization of enamel sections with P26-CS was not impeded by salivary enzymes. The peptide was not cytotoxic, irritating, or sensitizing. Fluorescently labeled P26-CS penetrated ~300 μm into the enamel of WSLs and ~100 μm into the dentin of NCCLs. After peptide treatment, quantitative light-induced fluorescence (QLF) and microcomputed tomography (μCT) indicated a gain in mineral density of WSLs. In NCCLs, scanning electron microscopy showed that the dentin was covered by a mineral layer of needle-shaped crystals. Our results show that the repair of artificial WSLs and NCCLs was achieved by P26 peptide-guided remineralization and demonstrate its potential to repair dental lesions. Full article

In this study, three dinuclear copper(II) complexes of ligand 2,6-bis[(N-methyl-piperazine-1-yl)methyl]-4-formyl phenol (L1) and one of 2,6-bis[(N-methylpiperazine-1-yl)methyl]-4-formyl phenol dimethylacetal (L2) with copper(II) ions have been investigated as new types of biomimetic catalysts for the oxidative transformation of different aminophenols and phenyldiamines. All the complexes of interest were newly synthesized and further characterized by IR spectroscopy, UV-Vis and mass spectrometry, X-ray diffraction, and selected electrochemical measurements. Crystal structures of these dinuclear copper(II) complexes have revealed that the coordination-shell geometry of copper atoms is close to a tetragonal pyramid. Catecholase, phenoxazinone synthase, and horseradish peroxidase-like activities were observed in pure methanol and water–methanol mixtures in the presence of molecular oxygen. The potential applicability of the complexes under study is discussed with respect to their possibilities and limitations in the replacement of natural copper-containing oxidoreductases in the oxidative degradation of water-insoluble chlorinated aminophenols in the dye industry or in the production of phenoxazine-based drugs. Full article

Treating the surfaces of dental implants in an alkaline medium allows us to obtain microstructures of sodium titanate crystals that favor the appearance of apatite in the physiological environment, producing osteoconductive surfaces. In this research, 385 discs made of titanium used in dental implants underwent different NaOH treatments with a 6M concentration at 600 °C and cooling rates of 20, 50, 75, and 115 °C/h. Using high-resolution electron microscopy, the microstructures were observed, and the different crystal sizes were determined and compared with control samples (those without biomimetic treatment). Roughness, wettability, surface energy and the sodium content of the surface were determined. The different surfaces were cultured with human osteoblastic cells; cell adhesion was determined at 3 and 14 days, and the degree of mineralization was determined at 14 days via alkaline phosphatase levels. Variations in the microstructure and size of sodium titanate crystals in NaOH solutions rich (1 g/L) or low in calcium (approximately 100 ppm) were determined. The results show that as the cooling rate increases, the size of the crystals decreases (from 0.4 μm to 0.8 μm) except for the case of 115 °C/h, when the rate is too fast for crystalline nucleation to occur on the surface of the titanium. The thermochemical treatment does not influence the roughness or the cooling rate since a Sa of 0.21 μm is maintained. However, the presence of titanate causes a decrease in the contact angle from 70° to 42° and, in turn, causes an increase in the total surface energy from 35 to 49.5 mJ/m², with the polar component standing out in this energy increase. No variations were observed in the thermochemical treatments in the presence of sodium, which was around 1200 ppm. It was observed that as the size of the crystals decreases, cell adhesion increases at 3 days and decreases at 14 days. This is because finer crystals on the surface are already in the mineralization process, as demonstrated using the level of alkaline phosphatase that is maximal for the cooling rate of 75 °C/h. It was possible to confirm that the variations in the concentrated NaOH solutions with different calcium contents did not affect the crystal sizes or the microstructure of the surface. This research makes it possible to obtain dental implants with different mineralization speeds depending on the cooling rate applied. Full article

The purpose of coatings is to protect or enhance the functionality of the substrate material, irrespective of the field in which the material was designed. The use of coatings in medicine is rapidly expanding with the objective of enhancing the osseointegration ability of metallic materials such as titanium. The aim of this study was to obtain biomimetic hydroxyapatite (HAp)-based coatings on titanium by using the pulsed galvanostatic method. The morphology of the HAp-based coatings revealed the presence of very thin and wide plate-like crystals, grown perpendicular to the Ti substrate, while the chemical composition highlighted a Ca/P ratio of 1.66, which is close to that of stoichiometric HAp (1.67). The main phases and chemical bonds identified confirmed the presence of the HAp phase in the developed coatings. A roughness of 228 nm and a contact angle of approx. 17° were obtained for the HAp coatings, highlighting a hydrophilic character. In terms of biomineralization and electrochemical behavior, it was shown that the HAp coatings have significantly enhanced the titanium properties. Finally, the in vitro cell tests carried out with human mesenchymal stem cells showed that the Ti samples coated with HAp have increased cell viability, extracellular matrix, and Ca intracellular deposition when compared with the uncoated Ti, indicating the beneficial effect. Full article

Transition metal oxide magnetite (Fe₃O₄) is recognized as a potential anode material for lithium-ion batteries owing to its high theoretical specific capacity, modest voltage output, and eco-friendly character. It is a challenging task to engineer high-performance composite materials by effectively dispersing Fe₃O₄ crystals with limited sizes in a well-designed supporting framework following sustainable approaches. In this work, the naturally abundant plant products sodium lignosulfonate (Lig) and sodium cellulose (CMC) were selected to coprecipitate with Fe³⁺ ions under mild hydrothermal conditions. The Fe-Lig/CMC intermediate sediment with an optimized microstructure can be directly converted to the Lig/CMC-derived carbon matrix-supported Fe₃O₄ nanocomposite sample (Fe₃O₄@LigC/CC). Compared with the controlled Fe₃O₄@LigC material, the Fe₃O₄@LigC/CC nanocomposite provides superior electrochemical performance in the anode, which has inspiring specific capacities of 820.6 mAh g⁻¹ after 100 cycles under a current rate of 100 mA·g⁻¹ and 750.5 mAh g⁻¹ after 250 cycles, as well as more exciting rate capabilities. The biomimetic sample design and synthesis protocol closely follow the criteria of green chemistry and can be further developed in wider scenarios. Full article

Supported lipid bilayers (SLBs) are low-complexity biomimetic membranes, serving as popular experimental platforms to study membrane organization and lipid transfer, membrane uptake of nanoparticles and biomolecules, and many other processes. Quartz crystal microbalance with dissipation monitoring has been utilized to probe the influence of several parameters on the quality of SLBs formed on Au- and SiO₂-coated sensors. The influence of the aqueous medium (i.e., buffer type) and the adsorption temperature, above and below the lipid melting point, is neatly explored for SLBs of 1,2-dimyristoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine formed by a solvent exchange. Below the lipid melting temperature, quality variations are observed upon the formation on Au and SiO₂ surfaces, with the SLBs being more homogeneous for the latter. We further investigate how the buffer affects the detection of lipid melting in SLBs, a transition that necessitates high-sensitivity and time-consuming surface-sensitive techniques to be detected. Full article

The microstructure of bone consists of nano-hydroxyapatite (nano-HA) crystals aligned within the interspaces of collagen fibrils. To emulate this unique microstructure of bone, this work applied two biomimetic techniques to obtain bone-like microstructures in vitro, that is, combining the construction of collagen liquid crystal hydrogel (CLCH) with the application of a polymer-induced liquid precursor (PILP) mineralization process. Upon the elevation of pH, the collagen macromolecules within the collagen liquid crystal (CLC) were activated to self-assemble into CLCH, whose fibrils packed into a long and dense fiber bundle in high orientation, emulating the dense-packed matrix of bone. We demonstrated that the fibrillar mineralization of CLCH, leading to a bone-like nanostructured inorganic material part, can be achieved using the PILP crystallization process to pre-mineralize the dense collagen substrates of CLCH with CaCO₃, immediately followed by the in situ mineral phase transformation of CaCO₃ into weak-crystalline nano-HA. The combination of CLCH with the biomineralization process of PILP, together with the mineral phase transformation, achieved the in vitro simulation of the nanostructures of both the organic extracellular matrix (ECM) and inorganic ECM of bone. This design would constitute a novel idea for the design of three-dimension biomimetic bone-like material blocks for clinical needs. Full article

Lyotropic liquid crystals represent an important class of anisotropic colloid systems. Their integration with optically active nanoparticles can provide us with responsive luminescent media that offer new fundamental and applied solutions for biomedicine. This paper analyzes the molecular-level behavior of such composites represented by tetraethylene glycol monododecyl ether and nanoscale carbon dots in microfluidic channels. Microfluidic confinement allows for simultaneously applying multiple factors, such as flow dynamics, wall effects, and temperature, for the precise control of the molecular arrangement in such composites and their resulting optical properties. The microfluidic behavior of composites was characterized by a set of analytical and modeling tools such as polarized and fluorescent microscopy, dynamic light scattering, and fluorescent spectroscopy, as well as image processing in Matlab. The composites were shown to form tunable anisotropic intermolecular structures in microchannels with several levels of molecular ordering. A predominant lamellar structure of the composites was found to undergo additional ordering with respect to the microchannel axis and walls. Such an alignment was controlled by applying shear and temperature factors to the microfluidic environment. The revealed molecular behavior of the composite may contribute to the synthesis of hybrid organized media capable of polarized luminescence for on-chip diagnostics and biomimetics. Full article

Introduction. Modern medicine depends on biomaterials. Thus, it is imperative that these materials continue to be developed and improved. Methods. This work aimed at designing hydroxyapatite-based coatings (HAp) with high osseointegration properties by developing a biomimetic morphology that resembles that of natural HAp found in bone tissue. The biomimetic HAp coatings with plate-like morphology were successfully obtained using the pulsed galvanostatic electrochemical approach on pure Ti discs. The coatings were investigated in terms of surface morphology, chemical and phasic composition, in vitro bioactivity, and cell interaction. Results and Discussion. The morphological investigations revealed that using electrochemical deposition, HAp-based coatings with very thin and wide plate-like crystals can be obtained. The chemical composition highlighted that both Ca and P are present, and that the Ca/P ratio registered values of 1.66, being close to that of the stoichiometric HAp of 1.67. The phasic composition analysis showed that the main phase consisted of hydroxyapatite (ICDD #09-0432), with a crystallinity of ~25%. The biomineralization ability of the cp-Ti substrate was improved by the HAp-based coatings, reaching a maximum value of 9.7 mg after 3 weeks of immersion in simulated body fluid (SBF) compared to the Ti samples which gained a mass of only 0.3 mg after the same period. The in vitro experiments using human mesenchymal stem cells demonstrated that the HAp-based coatings enhanced the extracellular matrix, the intracellular deposition of Ca, and cell viability when compared to the cp-Ti substrate, demonstrating the advantages of the developed coatings. Conclusions. Therefore, the outcomes confirm that coatings with improved and adjustable properties can be designed for medical applications by using the electrochemical deposition technique. Full article

Triply periodic minimal surfaces (TPMSs) are found in many natural objects including butterfly wings, sea urchins, and biological membranes. They simultaneously have zero mean curvature at every point and a crystallographic group symmetry. A metamaterial can be created from such periodic surfaces or used as a reinforcement of a composite material. While a TPMS as a mathematical object has been known since 1865, only novel additive manufacturing (AM) technology made it possible to fabricate cellular materials with complex TPMS shapes. Cellular TPMS-based metamaterials have remarkable properties related to wetting/liquid penetration, shock absorption, and the absence of stress concentrators. Recent studies showed that TPMSs are also found in natural crystals when electron surfaces are considered. Artificial crystal-inspired metamaterials mimic such crystals including zeolites and schwarzites. These metamaterials are used for shock, acoustic waves, and vibration absorption, and as structural materials, heat exchangers, and for other applications. The choice of the crystalline cell of a material, as well as its microstructure, plays a decisive role in its properties. The new area of crystal-inspired materials has many common features with traditional biomimetics with models being borrowed from nature and adjusted for engineering applications. Full article

The toughness of silk naturally obtained from spiders and silkworms exceeds that of all other natural and man-made fibers. These insects transform aqueous protein feedstocks into mechanically specialized materials, which represents an engineering phenomenon that has developed over millions of years of natural evolution. Silkworms have become a new research hotspot due to the difficulties in collecting spider silk and other challenges. According to continuous research on the natural spinning process of the silkworm, it is possible to divide the main aspects of bionic spinning into two main segments: the solvent and behavior. This work focuses on the various methods currently used for the spinning of artificial silk fibers to replicate natural silk fibers, providing new insights based on changes in the fiber properties and production processes over time. Full article

Hybrid materials based on calcium phosphates and synthetic polymers can potentially be used for caries protection due to their similarity to hard tissues in terms of composition, structure and a number of properties. This study is focused on the biomimetic synthesis of hybrid materials consisting of hydroxiapatite and the zwitterionic polymers polysulfobetaine (PSB) and polycarboxybetaine (PCB) using controlled media conditions with a constant pH of 8.0–8.2 and Ca/P = 1.67. The results show that pH control is a dominant factor in the crystal phase formation, so nano-crystalline hydroxyapatite with a Ca/P ratio of 1.63–1.71 was observed as the mineral phase in all the materials prepared. The final polymer content measured for the synthesized hybrid materials was 48–52%. The polymer type affects the final microstructure, and the mineral particle size is thinner and smaller in the synthesis performed using PCB than using PSB. The final intermolecular interaction of the nano-crystallized hydroxyapatite was demonstrated to be stronger with PCB than with PSB as shown by our IR and Raman spectroscopy analyses. The higher remineralization potential of the PCB-containing synthesized material was demonstrated by in vitro testing using artificial saliva. Full article