Bioinspired oriented calcium phosphate nanocrystal arrays with bactericidal and osteogenic properties.

The global diffusion of antibiotic resistance poses a severe threat to public health. Addressing antibiotic-resistant infections requires innovative approaches, such as antibacterial nanostructured surfaces (ANSs). These surfaces, featuring ordered arrays of nanostructures, exhibit the ability to kill bacteria upon contact. However, most currently developed ANSs utilize bioinert materials, lacking bioactivity crucial for promoting tissue regeneration, particularly in the context of bone infections. This study introduces ANSs composed of bioactive calcium phosphate nanocrystals. Two distinct ANSs were created through a biomineralization-inspired growth of amorphous calcium phosphate (ACP) precursors. The ANSs demonstrated efficient antibacterial properties against both Gram-negative (P. aeruginosa) and Gram-positive (S. aureus) antibiotic resistant bacteria, with up to 75 % mortality in adhered bacteria after only 4 h of contact. Notably, the ANS featuring thinner and less oriented nano-needles exhibited superior efficacy attributed to simultaneous membrane rupturing and oxidative stress induction. Moreover, the ANSs facilitate the proliferation of mammalian cells, enhancing adhesion, spreading, and reducing oxidative stress. The ANSs displayed also significant bioactivity towards human mesenchymal stem cells, promoting colonization and inducing osteogenic differentiation. Specifically, the ANS with thicker and more ordered nano-needles demonstrated heightened effects. In conclusion, ANSs introduced in this work have the potential to serve as foundation for developing bone graft materials capable of eradicate site infections while concurrently stimulating bone regeneration. STATEMENT OF SIGNIFICANCE: Nanostructured surfaces with antibacterial properties through a mechano-bactericidal mechanism have shown significant potential in fighting antibiotic resistance. However, these surfaces have not been fabricated with bioactive materials necessary for developing devices that are both antibacterial and able to stimulate tissue regeneration. This study demonstrates the feasibility of creating nanostructured surfaces of ordered calcium phosphate nano-needles through a biomineralization-inspired growth. These surfaces exhibit dual functionality, serving as effective bactericidal agents against Gram-negative and Gram-positive antibiotic-resistant bacteria while also promoting the proliferation of mammalian cells and inducing osteogenic differentiation of human mesenchymal stem cells. Consequently, this approach holds promise in the context of bone infections, introducing innovative nanostructured surfaces that could be utilized in the development of antimicrobial and osteogenic grafts.

The effect of avian eggshell membrane structure on microbial penetration: A simulation study.

Avian eggshells exhibit excellent antimicrobial properties. In this study, we conducted simulation experiments to explore the defense mechanisms of eggshell membranes with regards to their physical features. We developed a mathematical model for the movement of microorganisms and estimated their penetration ratio into eggshell membranes based on several factors, including membrane thickness, microbial size, directional drift, and attachment probability to membrane fibers. These results not only suggest that an eggshell membrane with multiple layers and low porosity indicates high antimicrobial performance, but also imply that the fibrous network structure of the membrane might contribute to effective defense. Our simulation results aligned with experimental findings, specifically in measuring the penetration time of Escherichia coli through the eggshell membrane. We briefly discuss the significance and limitations of this pilot study, as well as the potential for these results, to serve as a foundation for the development of antimicrobial materials.

Mechanisms of Biomolecular Self-Assembly Investigated Through In Situ Observations of Structures and Dynamics.

Biomolecular self-assembly of hierarchical materials is a precise and adaptable bottom-up approach to synthesizing across scales with considerable energy, health, environment, sustainability, and information technology applications. To achieve desired functions in biomaterials, it is essential to directly observe assembly dynamics and structural evolutions that reflect the underlying energy landscape and the assembly mechanism. This review will summarize the current understanding of biomolecular assembly mechanisms based on in situ characterization and discuss the broader significance and achievements of newly gained insights. In addition, we will also introduce how emerging deep learning/machine learning-based approaches, multiparametric characterization, and high-throughput methods can boost the development of biomolecular self-assembly. The objective of this review is to accelerate the development of in situ characterization approaches for biomolecular self-assembly and to inspire the next generation of biomimetic materials.

Construction of Wearable Touch Sensors by Mimicking the Properties of Materials and Structures in Nature.

Wearable touch sensors, which can convert force or pressure signals into quantitative electronic signals, have emerged as essential smart sensing devices and play an important role in various cutting-edge fields, including wearable health monitoring, soft robots, electronic skin, artificial prosthetics, AR/VR, and the Internet of Things. Flexible touch sensors have made significant advancements, while the construction of novel touch sensors by mimicking the unique properties of biological materials and biogenetic structures always remains a hot research topic and significant technological pathway. This review provides a comprehensive summary of the research status of wearable touch sensors constructed by imitating the material and structural characteristics in nature and summarizes the scientific challenges and development tendencies of this aspect. First, the research status for constructing flexible touch sensors based on biomimetic materials is summarized, including hydrogel materials, self-healing materials, and other bio-inspired or biomimetic materials with extraordinary properties. Then, the design and fabrication of flexible touch sensors based on bionic structures for performance enhancement are fully discussed. These bionic structures include special structures in plants, special structures in insects/animals, and special structures in the human body. Moreover, a summary of the current issues and future prospects for developing wearable sensors based on bio-inspired materials and structures is discussed.

Spectroscopic behavior differences between lumazine and alloxazine in the DMSO-water mixture.

The absorption and emission spectra were investigated for lumazine, alloxazine and their cyanated or fluorinated derivatives, respectively. The spectroscopic properties were modulated by varying water concentration in dimethyl sulfoxide (DMSO). Some intriguing experimental results were found for the samples containing 65 % of water and 35% of DMSO. This finding is consistent with previously published molecular dynamics (MD) simulations confirming the concept of the 'local bulk' model. In this case, a notable decrease in absorption and emission intensities was registered, even larger than the water quenching observed in other cases. The changes in midrange DMSO concentrations could be explained by the formation of local solvents structures as predicted by MD, specifically the formation of DMSO·2H2O dimers. Experimentally, the cyano-substituted lumazine has shown a remarkable sensitivity to DMSO concentration. The spectroscopic measurements were interpreted using the density functional theory where the implicit DMSO solvent model was combined with explicit water molecules. Together with its enhanced water solubility, the cyanated lumazine derivate could be used for non-destructive DMSO detection in vitro for applications such as drug uptake monitoring, since DMSO is often used in pharmaceutical practice.

Bio-inspired Superwettable Surface for the Detection of Cancer Biomarker: A Mini Review.

Inspired by nature, superwettable material-based biosensors have aroused wide interests due to their potential in cancer biomarker detection. This mini review mainly summarized the superwettable materials as novel biosensing substrates for the development of evaporation-induced enrichment-based signal amplification and visual biosensing method. Biosensing applications based on the superhydrophobic surfaces, superwettable micropatterned surfaces, and slippery lubricant-infused porous surfaces for various cancer biomarker detections were described in detail. Finally, an insight of remaining challenges and perspectives of superwettable biosensor is proposed.

Continuous, Large-Scale, and High Proportion of Bioinspired Phosphogypsum Composites via Reactive Extrusion.

Biological matter evolution provides an idea for the human design and synthesis of new materials. However, biomimetic materials only stay in laboratory-scale models, and their large-scale industrial applications are yet to be realized. Here, inspired by nacre's architecture, we report a continuous, large-scale method to fabricate phosphogypsum composites by reactive extrusion strategy. After curing for seven days, with more than 50 wt% of beta-hemihydrate phosphogypsum (ß-HPG), the compressive strength and softening coefficient were 24.98 MPa and 0.78, increasing by 110.0% and 20.0%, respectively, compared to the pouring method. The results show that the screw extrusion process can improve the mechanical strength and waterproof properties of ß-HPG hydration specimens without any special chemical admixtures and cements.

Microstructure and nanomechanical properties of the exoskeleton of an ironclad beetle (Zopherus haldemani).

This study examined natural composite structures within the remarkably strong exoskeleton of the southwestern ironclad beetle (Z. haldemani). Structural and nanomechanical analyses revealed that the exoskeleton's extraordinary resistance to external forces is provided by its exceptional thickness and multi-layered structure, in which each layer performed a distinct function. In detail, the epicuticle, the outmost layer, comprised 3%-5% of the overall thickness with reduced Young's moduli of 2.2-3.2 GPa, in which polygonal-shaped walls (2-3µm in diameter) were observed on the surface. The next layer, the exocuticle, consisted of 17%-20% of the total thickness and exhibited the greatest Young's moduli (∼15 GPa) and hardness (∼800 MPa) values. As such, this layer provided the bulk of the mechanical strength for the exoskeleton. While the endocuticle spanned 70%-75% of the total thickness, it contained lower moduli (∼8-10 GPa) and hardness (∼400 MPa) values than the exocuticle. Instead, this layer may provide flexibility through its specifically organized chitin fiber layers, known as Bouligand structures. Nanoindentation testing further reiterated that the various fibrous layer orientations resulted in different elastic moduli throughout the endocuticle's cross-section. Additionally, this exoskeleton prevented delamination within the composite materials by overlapping approximately 5%-19% of each fibrous stack with neighboring layers. Finally, the innermost layer, the epidermis contributing 5%-7 % of the total thickness, contains attachment sites for muscle and soft tissue that connect the exoskeleton to the beetle. As such, it is the softest region with reduced Young's modulus of ∼2-3 GPa and hardness values of ∼290 MPa. These findings can be applied to the development of innovative, fiber-reinforced composite materials.

BIO-INSPIRED MAGNETIC BEADS FOR ISOLATION OF SPERM FROM HETEROGENOUS SAMPLES IN FORENSIC APPLICATIONS.

Rapid and efficient processing of sexual assault evidence will accelerate forensic investigation and decrease casework backlogs. The standardized protocols currently used in forensic laboratories require the continued innovation to handle the increasing number and complexity of samples being submitted to forensic labs. Here, we present a new technique leveraging the integration of a bio-inspired oligosaccharide (i.e., Sialyl-LewisX) with magnetic beads that provides a rapid, inexpensive, and easy-to-use strategy that can potentially be adapted with current differential extraction practice in forensics labs. This platform (i) selectively captures sperm; (ii) is sensitive within the forensic cut-off; (iii) provides a cost effective solution that can be automated with existing laboratory platforms; and (iv) handles small volumes of sample (∼200 µL). This strategy can rapidly isolate sperm within 25 minutes of total processing that will prepare the extracted sample for downstream forensic analysis and ultimately help accelerate forensic investigation and reduce casework backlogs.

The Potential of Honeybee Products for Biomaterial Applications.

The development of biomaterials required continuous improvements in their properties for new tissue engineering applications. Implants based on biocompatible materials and biomaterial-based dressings are susceptible to infection threat; moreover, target tissues can suffer injuring inflammation. The inclusion of nature-derived bioactive compounds usually offers a suitable strategy to expand or increase the functional properties of biomaterial scaffolds and can even promote tissue healing. Honey is traditionally known for its healing property and is a mixture of phytochemicals that have a proven reputation as antimicrobial, anti-inflammatory, and antioxidant agents. This review discusses on the potential of honey and other honeybee products for biomaterial improvements. Our study illustrates the available and most recent literature reporting the use of these natural products combined with different polymeric scaffolds, to provide original insights in wound healing and other tissue regenerative approaches.

Bio-Inspired Lotus-Fiber-like Spiral Hydrogel Bacterial Cellulose Fibers.

Hydrogel materials with high water content and good biocompatibility are drawing more and more attention now, especially for biomedical use. However, it still remains a challenge to construct hydrogel fibers with enough strength and toughness for practical applications. Herein, we report a bio-inspired lotus-fiber-mimetic spiral structure hydrogel bacterial cellulose fiber with high strength, high toughness, high stretchability, and energy dissipation, named biomimetic hydrogel fiber (BHF). The spiral-like structure endows BHF with excellent stretchability through plastic deformation and local failure, assisted by the breaking-reforming nature of the hydrogen bonding network among cellulose nanofibers. With the high strength, high stretchability, high energy dissipation, high hydrophilicity, porous structure, and excellent biocompatibility, BHF is a promising hydrogel fiber for biomedicine. The outstanding stretchability and energy dissipation of BHF allow it to absorb energy from the tissue deformation around a wound and effectively protect the wound from rupture, which makes BHF an ideal surgical suture.

A Modular Strategy for Functional Pressure Sensitive Adhesives.

A modular approach to synthesizing functional pressure sensitive adhesives (PSAs) was introduced, wherein a modifiable acrylic PSA copolymer was synthesized by copolymerizing common PSA monomers with 6 mol % glycidyl methacrylate, allowing for subsequent functional group modification via the pendant epoxide functionality. This postmodification technique has the advantage of allowing the installation of a variety of functional groups relevant to adhesion, without variation of molecular weight. Because comparisons of cohesive and adhesive performance of candidate PSAs can be complicated by molecular weight differences, this strategy simplifies direct comparisons of the effects of functional groups on performance. As a proof of concept, a mussel-inspired catecholic PSA was synthesized by postreaction of the epoxide scaffold polymer with a thiol-modified catechol, allowing the effect of catechol on underlying structure-property relationships to be determined without variation in molecular weight. The mechanical performance of catecholic PSA was compared to relevant control PSAs by using industry-standard 180° peel and static shear tests, revealing an increase in peel strength achieved through catechol modification. Moreover, we observed an unexpected enhancement in PSA cohesive strength attributed to oxidation of catechol, which cannot be attributed to differences in molecular weight, a common source of changes in PSA cohesive strength.

High-Loading Boron Nitride-Based Bio-Inspired Paper with Plastic-like Ductility and Metal-like Thermal Conductivity.

Although desirable in next-generation flexible electronics, fabricating hybrid film materials with excellent integration of mechanical and thermally conductive yet electrically insulating properties is still a challenge. In mollusk nacre, a small volume of the chitin nanofiber framework hosts 95 vol % CaCO3 microplatelets, enabling the high-loading natural composites to exhibit a ductile deformation behavior. Inspired by this, we fabricate a large-area, boron nitride-based bio-inspired paper using a facile sol-gel-film conversion approach, in which BN microplatelets with a loading of 40-80 wt % are embedded into a 3D poly(p-phenylene benzobisoxazole) nanofiber framework. Because of the vital role of the 3D nanofiber framework, the BN-based paper exhibits plastic-like ductility (38-80%), ultrahigh toughness (10-100 MJ m-3), and good folding endurance. The high-loading BN platelets form an oriented, percolative network and endow the paper with outstanding in-plane thermal conductivity (77.1-214.2 W m-1 K-1) comparable to that of some metals, such as aluminum alloys (108-230 W m-1 K-1). Using the electrically insulating BN-based paper as a flexible substrate, we demonstrate its promising application for lowering the temperature of electronic devices.

Polydopamine-assisted immobilization of a zinc(II)-derived metal-organic cage as a stationary phase for open-tubular capillary electrochromatography.

A capillary column was modified with a soluble zinc(II)-derived metal-organic cage (MOC) [Zn2L] as the stationary phase to obtain a new coating layer for use in open-tubular capillary electrochromatography. The inner surface of the capillary was first coated with a layer of polydopamine. Then, a solution of the MOC in dichloromethane was introduced into the capillary upon which it is bonded both covalently and non-covalently. The resulting coating layer on the capillary was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The results demonstrated the successful formation of the [Zn2L] modified open-tubular column. The column showed good separation performance towards neutral compounds (such as methylbenzene, ethylbenzene, n-propylbenzene and n-butylbenzene), acidic drugs (such as ibuprofen, ketoprofen, flurbiprofen and diclofenac sodium), food additives (such as parabens, vanillin and related phenolic compounds) and small biomolecules (such as nucleosides and nucleotide bases) by π-interaction and hydrophobic interaction. It also exhibited good precision, the relative standard deviations of the retention time for intra-day, inter-day runs and column-to-column being <1.6%, 2.8%, and 4.0%, respectively. Graphical abstract Schematic presentation of the open-tubular column modified with zinc(II)-derived metal-organic cage by polydopamine-assisted strategy onto the inner wall of capillary for electrochromatographic separations.

Cupric Oxide Nanostructures from Plasma Surface Modification of Copper.

Taking inspiration from the hydrophilic and superhydrophilic properties observed from the nanostructures present on the leaves of plants such as Alocasia odora, Calathea zebrina, and Ruelia devosiana, we were able to synthesize cupric oxide (CuO) nanostructures from the plasma surface modification of copper (Cu) that exhibits hydrophilic and superhydrophilic properties. The Cu sheets were exposed to oxygen plasma produced from the P300 plasma device (Alliance Concept, Cran-Gevrier, France) at varying power, irradiation times, gas flow rates, and pulsing duty cycles. The untreated and plasma-treated Cu sheets were characterized by contact angle measurements, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) to determine the changes in the surface of Cu before and after plasma treatment. Results showed that plasma-treated Cu sheets exhibited enhanced wetting properties compared to untreated Cu. We attributed the decrease in the measured water contact angles after plasma treatment to increased surface roughness, formation of CuO nanostructures, and transformation of Cu to either CuO2 or Cu2O3. The presence of the CuO nanostructures on the surface of Cu is very useful in terms of its possible applications, such as: (1) in antimicrobial and anti-fouling tubing; (2) in the improvement of heat dissipation devices, such as microfluidic cooling systems and heat pipes; and (3) as an additional protection to Cu from further corrosion. This study also shows the possible mechanisms on how CuO, CuO2, and Cu2O3 were formed from Cu based on the varying the plasma parameters.

Novel Riboflavin-Inspired Conjugated Bio-Organic Semiconductors.

Flavins are known to be extremely versatile, thus enabling routes to innumerable modifications in order to obtain desired properties. Thus, in the present paper, the group of bio-inspired conjugated materials based on the alloxazine core is synthetized using two efficient novel synthetic approaches providing relatively high reaction yields. The comprehensive characterization of the materials, in order to evaluate the properties and application potential, has shown that the modification of the initial alloxazine core with aromatic substituents allows fine tuning of the optical bandgap, position of electronic orbitals, absorption and emission properties. Interestingly, the compounds possess multichromophoric behavior, which is assumed to be the results of an intramolecular proton transfer.

Bio-inspired solute enables preservation of human oocytes using minimum volume vitrification.

The ability to cryopreserve human oocytes has significant potential for fertility preservation. Current cryopreservation methods still suffer from the use of conventional cryoprotectants, such as dimethyl sulphoxide (DMSO), causing loss of viability and function. Such injuries result from the toxicity and high concentration of cryoprotectants, as well as mechanical damage of cells due to ice crystal formation during the cooling and rewarming processes. Here we report the preservation of human oocytes following vitrification using an innovative bio-inspired cryoprotectant integrated with a minimum volume vitrification approach. The results demonstrate that the recovered human oocytes maintained viability following vitrification and rewarming. Moreover, when this approach was used to vitrify mouse oocytes, the recovered oocytes preserved their viability and function following vitrification and rewarming. This bio-inspired approach substitutes DMSO, a well-known toxic cryoprotectant, with ectoine, a non-toxic naturally occurring solute. The bio-inspired vitrification approach has the potential to improve fertility preservation for women undergoing cancer treatment and endangered mammal species.