Bioinspired Stabilization of Amorphous Calcium Carbonate by Carboxylated Nanocellulose Enables Mechanically Robust, Healable, and Sensing Biocomposites

Using reduced sericin as a green resist for precise pattern fabrication via water-based lithography

The use of toxic resists and complex procedures has impeded the resolution and quality of micro/nanofabrication on virtually arbitrary substrates via photolithography. To fabricate a precise and high-resolution pattern, a sericin nanofilm-based coating was developed by reducing disulfide bonds and subsequently assembling sericin protein. Upon exposure to ultraviolet (UV) light, intermolecular amide bonds in sericin are cleaved through the action of a reducing agent, allowing the reduced sericin (rSer) coating to exhibit the functional ability to generate diverse geometric micro/nanopatterns through photomask-governed photolithography. The rSer film serves as a platform for the encapsulation of fluorescent molecules, enabling fluorescent micropatterns applicable in anti-counterfeiting and encryption. In addition, the patterned rSer nanofilms support biocompatible cell proliferation. With their excellent chemical stability, high-resolution geometric patterns can be transferred onto silicon substrates through chemical etching, resulting in periodic chemical etching patterns that display structural colours. Inspired by the micro/nanostructures of lotus leaves, elliptical microstructures exhibit superhydrophobic behaviour, highlighting the versatility of the rSer film for applications in semiconductors, anti-counterfeiting, smart displays, and superhydrophobic coatings.

Colorimetric Fabry-Pérot Sensor with Hetero-Structured Dielectric for Humidity Monitoring

A full-color colorimetric humidity sensor with high brightness is proposed by using a hetero-structured dielectric film in a metal-insulator-metal (MIM) resonator. A humidity-responsive polymer is designed to graft on top of a metal-organic frameworks (MOFs) thin film (MOFs-Polymer) as insulator layer in the resonator. Programmable tuning of reflected color is achieved by controlling the polymer thicknesses, and finite difference time domain simulation of light-matter interactions at subwavelength scales proves the dependence of the reflected wavelength on dielectric layer thickness of the resonator. Vivid full-color changing is realized during tracking humidity process due to swelling of the stimuli-responsive polymer. Ultrafast response (≈0.75 s) is achieved for tracking trace H2O from H2O/methanol mixture, which is ≈104 faster than that of the pure polymer-based MIM resonator. Meanwhile, the study observes significant spectral redshift because the porous MOFs film facilitates the preconcentration of external stimulus and improves the detection sensitivity of the resonator. Further, double-channel anti-counterfeiting multiplexing imaging is devised on the MIM resonator by photomask technology. Patterned encoding for security label is achieved on the MIM resonator by engineering humidity-tunable pixels of Au/MOFs-Polymer/Au and humidity-invalid pixels of Au/MOFs/Au.

Tunable Mechanical Properties in Biodegradable Cellulosic Bioplastics Achieved via Ring-Opening Polymerization

The development of bioplastics is advancing globally to promote a sustainable society. In this study, we designed cellulosic dual-network bioplastics to address the need for sustainable materials with balanced mechanical properties and biodegradability. Cellulose was used as the first network, and the second network was functionalized to enhance mechanical strength while preserving biodegradability. The dynamic covalent moieties within the second network were generated through dithiolane ring-opening polymerization. The ultimate tensile strength and flexural elongation were controlled within 8.8-193 MPa and 3.3-32.5%, respectively, depending on the degree of dynamic bonds. Moreover, the bioplastics exhibited gradual biodegradability, achieving approximately 30% degradation within 2 weeks. Interestingly, our bioplastics demonstrated the ability to coexist with plants, as their degradation did not negatively affect cell viability or plant growth. This study provides a promising approach to developing advanced bioplastics that reach sustainability goals while offering tunable mechanical properties.

Osteomimix: A Multidimensional Biomimetic Cascade Strategy for Bone Defect Repair

Despite advancements in biomimetic mineralization techniques, the repair of large-scale bone defects remains a significant challenge. Inspired by the bone formation process, a multidimensional biomimetic cascade strategy is developed by replicating the biomineralization cascade, emulating the hierarchical structure of bone, and biomimicking its biological functions for efficient bone regeneration. This strategy involves the photocrosslinking of sodium methacrylate carboxymethyl cellulose-stabilized amorphous magnesium-calcium phosphate with methacrylate-modified type I collagen to create a self-mineralizing hydrogel. The hydrogel is then integrated with either naturally derived or synthetic oriented bulk scaffolds. The resulting composite, named Osteomimix, provides excellent mechanical support and can be customized for irregular bone defects using CAD/CAM technology. Through in vitro and in vivo studies, this work finds that Osteomimix exhibits spontaneous in situ biomimetic mineralization in a cell-free environment, while modulating immune responses and promoting vascularized bone formation in a cell-dependent manner. Built on bone-specific insights, this strategy achieves biomimicry across temporal, spatial, and functional dimensions, facilitating the seamless integration of artificial constructs with the natural tissue repair dynamics.

Chiral Biomineral Structures: Synthesis and Inspiring Functional Materials

Biominerals with complex hierarchical structures present important roles, such as defense, predation, or communication, which spurs the scientists to design biomimetic strategies and mimic this microstructure. This review mainly focuses on the synthesized strategies of chiral biominerals and the inspirations in the design of the functional materials. Additive-assisted and template-oriented strategies can control mineral growth through intermolecular interactions, which triggers the chirality transfer from the molecular level to the macroscopic scale. Gel-based limited space reduces the solute diffusion rate and prompts the chiral morphology or helical structure evolution. These strategies play a synergetic role in the mineralization process. This growth process is commonly dominated by the nonclassical routes, and understanding this evolved mechanism is significant for the materials synthesis. The superior performance of the chiral minerals provides sufficient inspiration for materials manufacturing. The twisted layered structure design enhances the rigidity and toughness significantly, which provides a new sight in the hard materials preparation. Chirality arrangement displays the optical characteristic, which is expected to be applied in the sensing. Finally, further directions from mechanisms, and design to production are given.

Directed Inward Migration of S-Vacancy in Bi2S3 QDs for Selective Photocatalytic CO2 to CH3OH

The directional migration of S-vacancy is beneficial to the separation of photogenerated carriers and the transition of electrons in semiconductors. In this study, Bix/Bi2-xSy@carboxylic-cellulose (CC) photocatalyst with bionic chloroplast structure is obtained by electron beam irradiation to induce S-vacancy in Bi2S3@CC. The results of CO2 photoreduction experiments demonstrate that the reduction rate of CO2 to CH3OH by Bix/Bi2‒xS2.89@CC-450 samples is 10.74 µmol·g-1·h-1, and the selectivity is 92.82%. The results show that the inward migration behavior of the borderline S-vacancy (b-Sv) induces the redistribution of electrons in Bix/Bi2-xSy@CC. The Bi° clusters in Bix/Bi2-xSy@CC is conducive to adsorb CO2, and the internal S-vacancy (i-Sv) is conducive to adsorb CH3OH, which accelerate the transfer of gas-phase products to realize the controllable conversion of CO2 and photoreduction products at the gas-liquid-solid three-phase interface. This study provides a new idea for the development and utilization of green photocatalysts in clean energy.

Dual Nanofillers Reinforced Polymer-Inorganic Nanocomposite Film with Enhanced Mechanical Properties

Simultaneously improving the strength and toughness of polymer-inorganic nanocomposites is highly desirable but remains technically challenging. Herein, a simple yet effective pathway to prepare polymer-inorganic nanocomposite films that exhibit excellent mechanical properties due to their unique composition and structure is demonstrated. Specifically, a series of poly(methacrylic acid)x-block-poly(benzyl methacrylate)y diblock copolymer nano-objects with differing dimensions and morphologies is prepared by polymerization-induced self-assembly (PISA) mediated by reversible addition-fragmentation chain transfer polymerization (RAFT). Such copolymer nano-objects and ultrasmall calcium phosphate oligomers (CPOs) are used as dual fillers for the preparation of polymer-inorganic composite films using sodium carboxymethyl cellulose (CMC) as a matrix. Impressively, the strength and toughness of such composite films are substantially reinforced as high as up to 202.5 ± 14.8 MPa and 62.3 ± 7.9 MJ m-3, respectively. Owing to the intimate interaction between the polymer-inorganic interphases at multiple scales, their mechanical performances are superior to most conventional polymer films and other nanocomposite films. This study demonstrates the combination of polymeric fillers and inorganic fillers to reinforce the mechanical properties of the resultant composite films, providing new insights into the design rules for the construction of novel hybrid films with excellent mechanical performances.

Organic-Inorganic Copolymerization Induced Oriented Crystallization for Robust Lightweight Porous Composite

Porous composites are important in engineering fields for their lightweight, thermal insulation, and mechanical properties. However, increased porosity commonly decreases the robustness, making a trade-off between mechanics and weight. Optimizing the strength of solid structure is a promising way to co-enhance the robustness and lightweight properties. Here, acrylamide and calcium phosphate ionic oligomers are copolymerized, revealing a pre-interaction of these precursors induced oriented crystallization of inorganic nanostructures during the linear polymerization of acrylamide, leading to the spontaneous formation of a bone-like nanostructure. The resulting solid phase shows enhanced mechanics, surpassing most biological materials. The bone-like nanostructure remains intact despite the introduction of porous structures at higher levels, resulting in a porous composite (P-APC) with high strength (yield strength of 10.5 MPa) and lightweight properties (density below 0.22 g cm-3). Notably, the density-strength property surpasses most reported porous materials. Additionally, P-APC shows ultralow thermal conductivity (45 mW m-1 k-1) due to its porous structure, making its strength and thermal insulation superior to many reported materials. This work provides a robust, lightweight, and thermal insulating composite for practical application. It emphasizes the advantage of prefunctionalization of ionic oligomers for organic-inorganic copolymerization in creating oriented nanostructure with toughened mechanics, offering an alternative strategy to produce robust lightweight materials.

Strong, anti-swelling, and biodegradable seaweed-based straws with surface mineralized CaCO3 armor

While the extensive utilization of disposable plastic straws has resulted in significant environmental issues such as microplastics and soil and ocean pollution, the quest for alternative straws for versatile use remains a formidable challenge. Here, drawing inspiration from naturally water-resistant materials such as bones and sea urchins, we have developed seaweed-based straws with significantly improved water resistance and mechanical strength via in-situ mineralization of CaCO3 on their surfaces. Specifically, the COO- groups on the G (α-L-guluronate) blocks of alginate were employed to establish a robust cross-linked network, while the COO- groups on the M (β-D-mannuronate) blocks attracted free Ca2+ through electrostatic forces, thereby promoting CaCO3 nucleation. This effectively prevents COOH groups from hydrating, reducing swelling, and results in the fabrication of nano- to micron-sized CaCO3 particles that reinforce the structure without compromising the cross-linked network. Compared with the control group, the S5% sample (prepared with 5 % Na2CO3 solution) exhibited a 102 % increase in water contact angle, a 35 % decrease in swelling degree, and a 35.5 % and 37.5 % increase in ultimate flexural and tensile stress, respectively. Furthermore, the potential use of these straws as a waste for heavy metal adsorption was investigated, addressing environmental concerns while demonstrating economic feasibility.

Polydopamine-induced biomimetic mineralization strategy to generate hydroxyapatite for the preparation of carbon fiber composites with excellent mechanical properties

Living organisms have developed a miraculous biomineralization strategy to form multistage organic-inorganic composites through the orderly assembly of hard/soft substances, achieving mechanical enhancement of materials from the nanoscale to the macroscale. Inspired by biominerals, this study used polydopamine (PDA) coating as a template to induce the growth of hydroxyapatite (HAP) on the surface of carbon fibers (CFs) for enhancing the interfacial properties of the CF/epoxy resin composites. This polydopamine-assisted hydroxyapatite formation (pHAF) biomimetic mineralization strategy constructs soft/hard ordered structure on the CF surface, which not only improves the chemical reaction activity of the CFs but also increases the fiber surface roughness. This, in turn, enhances the interaction and loading delivery among the fibers and the matrix. Compared to the untreated carbon fiber/epoxy resin (CF/EP) composites, the prepared composites showed a substantial enhancement in interlaminar shear strength (ILSS), flexural strength, and interfacial shear strength (IFSS), with improvements of 45.2 %, 46.9 %, and 60.5 %, respectively. This can be attributed to the HAP nanolayers increasing the adhesion and mechanical interlocking with the CFs to the matrix. This study provides an interface modification method of biomimetic mineralization for the preparation of high strength CF composites.

Industrial manufacturing method and characterization of Ayurvedic marine drugs: mother pearl, cowry, coral and pearl

INTRODUCTION

Ayurvedic marine drugs derived from mollusc shells and coral are regularly used by Ayurvedic physicians to treat several disease conditions like acid peptic disease, irritable bowel syndrome, osteoporosis, etc. However, standard operating procedures for manufacturing these drugs and their complete characterization have not been published in the Ayurvedic Formulary and Ayurvedic Pharmacopeia of India to date.

METHODS

Present study describes the traditional manufacturing process and thorough characterization using classical and advanced analytical tools. The raw materials characters, in-process parameters, and finished product specifications have been elaborated to develop monographs. Especially, the identity and purity of raw coral and pearl were checked by Raman Spectroscopy and Energy Dispersive X-ray Fluorescence analysis.

RESULTS

In the finished product analysis, the X-Ray Diffraction study revealed that incineration after trituration with Aloe barbadensis leaf pulp or rose water converted the aragonite phase of calcium carbonate into calcite phase in mother pearl, cowry, and pearl while the calcite form of raw coral was retained. The prominent bands around 1390, 870, and 712 cm-1 detected by Fourier Transform-Infrared Spectroscopy and mass loss between 39-44% (w/w) revealed by thermogravimetric analysis confirmed the carbonate form of these calcium-based drugs. The finished products were very fine grayish-white powders constituted by irregularly shaped nano-micro particulate calcium carbonate exhibiting particle size between 600 nm (D10 value) to 1.2 µm (D90 value).

CONCLUSION

The quality control and assurance achieved in this study may be further utilized by the pharmaceutical industries to manufacture quality marine drugs and conduct efficacy studies.

Biomineral-Based Composite Materials in Regenerative Medicine

Regenerative medicine aims to address substantial defects by amplifying the body's natural regenerative abilities and preserving the health of tissues and organs. To achieve these goals, materials that can provide the spatial and biological support for cell proliferation and differentiation, as well as the micro-environment essential for the intended tissue, are needed. Scaffolds such as polymers and metallic materials provide three-dimensional structures for cells to attach to and grow in defects. These materials have limitations in terms of mechanical properties or biocompatibility. In contrast, biominerals are formed by living organisms through biomineralization, which also includes minerals created by replicating this process. Incorporating biominerals into conventional materials allows for enhanced strength, durability, and biocompatibility. Specifically, biominerals can improve the bond between the implant and tissue by mimicking the micro-environment. This enhances cell differentiation and tissue regeneration. Furthermore, biomineral composites have wound healing and antimicrobial properties, which can aid in wound repair. Additionally, biominerals can be engineered as drug carriers, which can efficiently deliver drugs to their intended targets, minimizing side effects and increasing therapeutic efficacy. This article examines the role of biominerals and their composite materials in regenerative medicine applications and discusses their properties, synthesis methods, and potential uses.

Guidelines derived from biomineralized tissues for design and construction of high-performance biomimetic materials: from weak to strong

Living organisms in nature have undergone continuous evolution over billions of years, resulting in the formation of high-performance fracture-resistant biomineralized tissues such as bones and teeth to fulfill mechanical and biological functions, despite the fact that most inorganic biominerals that constitute biomineralized tissues are weak and brittle. During the long-period evolution process, nature has evolved a number of highly effective and smart strategies to design chemical compositions and structures of biomineralized tissues to enable superior properties and to adapt to surrounding environments. Most biomineralized tissues have hierarchically ordered structures consisting of very small building blocks on the nanometer scale (nanoparticles, nanofibers or nanoflakes) to reduce the inherent weaknesses and brittleness of corresponding inorganic biominerals, to prevent crack initiation and propagation, and to allow high defect tolerance. The bioinspired principles derived from biomineralized tissues are indispensable for designing and constructing high-performance biomimetic materials. In recent years, a large number of high-performance biomimetic materials have been prepared based on these bioinspired principles with a large volume of literature covering this topic. Therefore, a timely and comprehensive review on this hot topic is highly important and contributes to the future development of this rapidly evolving research field. This review article aims to be comprehensive, authoritative, and critical with wide general interest to the science community, summarizing recent advances in revealing the formation processes, composition, and structures of biomineralized tissues, providing in-depth insights into guidelines derived from biomineralized tissues for the design and construction of high-performance biomimetic materials, and discussing recent progress, current research trends, key problems, future main research directions and challenges, and future perspectives in this exciting and rapidly evolving research field.

Construction of Mineralization Nanostructures in Polymers for Mechanical Enhancement and Functionalization

Mineralization capable of growing inorganic nanostructures efficiently, orderly, and spontaneously shows great potential for application in the construction of high-performance organic-inorganic composites. As a thermodynamically spontaneous solid-phase crystallization reaction involving dual organic and inorganic components, mineralization allows for the self-assembly of sophisticated and exclusive nanostructures within a polymer matrix. It results in a diversity of functions such as enhanced strength, toughness, electrical conductivity, selective permeability, and biocompatibility. While there are previous reviews discussing the progress of mineralization reactions, many of them overlook the significant benefits of interfacial regulation and functionalization that come from the incorporation of mineralized structures into polymers. Focusing on different means of assembly of mineralized nanostructures in polymer, the work analyzes their design principles and implementation strategies. Then, their different advantages and disadvantages are analyzed by combining nanostructures with organic substrates as well as involving the basis of different functionalizations. It is anticipated to provide insights and guidance for the future development of mineralized polymer composites and their application designs.

Biominerals and Bioinspired Materials in Biosensing: Recent Advancements and Applications

Inspired by nature's remarkable ability to form intricate minerals, researchers have unlocked transformative strategies for creating next-generation biosensors with exceptional sensitivity, selectivity, and biocompatibility. By mimicking how organisms orchestrate mineral growth, biomimetic and bioinspired materials are significantly impacting biosensor design. Engineered bioinspired materials offer distinct advantages over their natural counterparts, boasting superior tunability, precise controllability, and the ability to integrate specific functionalities for enhanced sensing capabilities. This remarkable versatility enables the construction of various biosensing platforms, including optical sensors, electrochemical sensors, magnetic biosensors, and nucleic acid detection platforms, for diverse applications. Additionally, bioinspired materials facilitate the development of smartphone-assisted biosensing platforms, offering user-friendly and portable diagnostic tools for point-of-care applications. This review comprehensively explores the utilization of naturally occurring and engineered biominerals and materials for diverse biosensing applications. We highlight the fabrication and design strategies that tailor their functionalities to address specific biosensing needs. This in-depth exploration underscores the transformative potential of biominerals and materials in revolutionizing biosensing, paving the way for advancements in healthcare, environmental monitoring, and other critical fields.

Exploiting Saturation Regimes and Surface Effects to Tune Composite Design: Single Platelet Nanocomposites of Peptoid Nanosheets and CaCO3

Mineral-polymer composites found in nature exhibit exceptional structural properties essential to their function, and transferring these attributes to the synthetic design of functional materials holds promise across various sectors. Biomimetic fabrication of nanocomposites introduces new pathways for advanced material design and explores biomineralization strategies. This study presents a novel approach for producing single platelet nanocomposites composed of CaCO3 and biomimetic peptoid (N-substituted glycines) polymers, akin to the bricks found in the brick-and-mortar structure of nacre, the inner layer of certain mollusc shells. The significant aspect of the proposed strategy is the use of organic peptoid nanosheets as the scaffolds for brick formation, along with their controlled mineralization in solution. Here, we employ the B28 peptoid nanosheet as a scaffold, which readily forms free-floating zwitterionic bilayers in aqueous solution. The peptoid nanosheets were mineralized under consistent initial conditions (σcalcite = 1.2, pH 9.00), with variations in mixing conditions and supersaturation profiles over time aimed at controlling the final product. Nanosheets were mineralized in both feedback control experiments, where supersaturation was continuously replenished by titrant addition and in batch experiments without a feedback loop. Complete coverage of the nanosheet surface by amorphous calcium carbonate was achieved under specific conditions with feedback control mineralization, whereas vaterite was the primary CaCO3 phase observed after batch experiments. Thermodynamic calculations suggest that time-dependent supersaturation profiles as well as the spatial distribution of supersaturation are effective controls for tuning the mineralization extent and product. We anticipate that the control strategies outlined in this work can serve as a foundation for the advanced and scalable fabrication of nanocomposites as building blocks for nacre-mimetic and functional materials.

Bioinspired pullulan-starch nanoplatelets nanocomposite films with enhanced mechanical properties

Inspired by the leaf-vein network structure, the pullulan-starch nanoplatelets (SNPs) bioinspired films with enhanced strength and toughness were successfully fabricated through a water evaporation-induced self-assembly technique. SNPs (SNP200 and SNP600) of two sizes were separated by differential centrifugation. Interactions between SNPs and pullulan during drying resulted in the vein-like network structure in both nanocomposite films when the appropriate amounts of SNP200 or SNP600 were added to pullulan, respectively. The TS and toughness values of pullulan with 1 % w/w SNP200 films reached up to 51.05 MPa and 69.65 MJ·m-3, which were 86 % and 223 % higher than those of the neat pullulan films, respectively. Moreover, the TS and toughness values of pullulan-SNP200 were significantly higher than those of pullulan-SNP600 films, when SNP content exceeded the 1 % w/w level. By applying a graph theory, the network structures were found to correlate with the mechanical properties of the pullulan-SNPs bioinspired films. The new strategy for designing starch nanoplatelets-based edible films that combine mechanical strength and toughness holds promises for the development of novel biobased composite materials for food packaging application.