Synthesis Of Biomimetic Materials Research Articles

Multi-Gradient Bone-Like Nanocomposites Induced by Strain Distribution.

The heterogeneity of bones is elegantly adapted to the local strain environment, which is critical for maintaining mechanical functions. Such an adaptation enables the strong correlation between strain distributions and multiple gradients, underlying a promising pathway for creating complex gradient structures. However, this potential remains largely unexplored for the synthesis of functional gradient materials. In this work, heterogeneous bone-like nanocomposites with complex structural and compositional gradients comparable to bones are synthesized by inducing strain distributions within the polymer matrix containing amorphous calcium phosphate (ACP). Uniaxial stretching of composite films exerts the highest strain in the center, which ceases gradually toward the sides, resulting in the gradual decrease of polymer alignment and crystallinity. Simultaneously, the center with high orientation traps most ACP during stretching due to the nanoconfinement effect, which in turn promotes the formation of aligned nanofibrous structures. The sides experiencing the least strain have the smallest amounts of ACP, characteristic of porous architectures. Further crystallization of ACP produces oriented apatite nanorods in the center with a larger crystalline/amorphous ratio than the sides because of template-induced crystallization. The combination of structural and compositional gradients leads to gradient mechanical properties, and the gradient span and magnitude correlate nicely with strain distributions. Accompanying bone-like mechanical gradients, the center is less adhesive and self-healable than the sides, which allows a better recovery after a complete cutting. Our work may represent a general strategy for the synthesis of biomimetic materials with complex gradients thanks to the ubiquitous presence of strain distributions in load-bearing structures.

A joint proteomic and genomic investigation provides insights into the mechanism of calcification in coccolithophores

Coccolithophores are globally abundant, calcifying microalgae that have profound effects on marine biogeochemical cycles, the climate, and life in the oceans. They are characterized by a cell wall of CaCO3 scales called coccoliths, which may contribute to their ecological success. The intricate morphologies of coccoliths are of interest for biomimetic materials synthesis. Despite the global impact of coccolithophore calcification, we know little about the molecular machinery underpinning coccolithophore biology. Working on the model Emiliania huxleyi, a globally distributed bloom-former, we deploy a range of proteomic strategies to identify coccolithogenesis-related proteins. These analyses are supported by a new genome, with gene models derived from long-read transcriptome sequencing, which revealed many novel proteins specific to the calcifying haptophytes. Our experiments provide insights into proteins involved in various aspects of coccolithogenesis. Our improved genome, complemented with transcriptomic and proteomic data, constitutes a new resource for investigating fundamental aspects of coccolithophore biology.

Controlled synthesis of biomimetic materials with protruding structures by in situ growth of silica nanorods via hydroxyl-localized droplet template method

Inspired by the Lotus-Effect in nature, biomimetic materials with a protruding structure have been prepared through a hydroxyl-localized droplet templating method, in which the droplets are formed by polyvinylpyrrolidone as a surfactant and sodium citrate as a stabilizer. Silica nanorods grow uniformly and densely unidirectionally on the surface of high silica fibers. With the adjustment of reaction conditions and reagent concentration, the aspect ratio of the nanorods is adjustable between 1.73 and 17.58, where the length and diameter are controllable in the range of 180–368 nm and 194–1489 nm, respectively. Meanwhile, the structure also undergoes changes from straight rod-like to curved linear shapes with curvature values up to 1.50. It is found that the hydroxyl group on the fiber surface, which adsorbs the attachment of emulsified droplets and participates in the condensation reaction of tetraethyl orthosilicate, serves as the key to the in-situ growth of silica nanorods. In addition, silica nanorods are also successfully grown on mullite fibers and basalt fibers yielding biomimetic materials with protruding structures. The mean lengths of silica nanorods on mullite and basalt fibers are 833 nm and 1361 nm, correspondingly, along with respective mean diameters of 379 nm and 271 nm.

Biomimetic Material Synthesis and its Application for Emerging Contaminant: Mini Review

Polymer Science: Peer Review Journal Biomimetic Material Synthesis and its Application for Emerging Contaminant: Mini Review Sabir Khan1,2*, Victor Douglas Dantas2, Maria Del Pilar Taboada Sotomayor2,3* and Gino Picasso1 1Laboratory of Physical Chemistry Research, Faculty of Sciences, National University of Engineering, Peru 2Institute of Chemistry, São Paulo State University (UNESP), Brazil 3National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM), Brazil *Corresponding author:Sabir Khan and Maria DPT Sotomayor, Laboratory of Physical Chemistry Research, Faculty of Sciences, National University of Engineering, Av. Tupac Amaru 210, Lima 25, Peru and National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCTDATREM), Araraquara, SP, Brazil Submission: March 07, 2022;Published: April 14, 2022 DOI: 10.31031/PSPRJ.2022.03.000564 ISSN: 2770-6613 Volume3 Issue3

Biofunctionalization of graphene and its two-dimensional analogues and synthesis of biomimetic materials: a review

Biofunctionalization of graphene and its two-dimensional analogues and synthesis of biomimetic materials: a review

Biomimetic Collagen/Zn2+-Substituted Calcium Phosphate Composite Coatings on Titanium Substrates as Prospective Bioactive Layer for Implants: A Comparative Study Spin Coating vs. MAPLE.

Synthesis of biomimetic materials for implants and prostheses is a hot topic in nanobiotechnology strategies. Today the major approach of orthopaedic implants in hard tissue engineering is represented by titanium implants. A comparative study of hybrid thin coatings deposition was performed by spin coating and matrix-assisted pulsed laser evaporation (MAPLE) onto titanium substrates. The Collagen-calcium phosphate (Coll-CaPs) combination was selected as the best option to mimic natural bone tissue. To accelerate the mineralization process, Zn2+ ions were inserted by substitution in CaPs. A superior thin film homogeneity was assessed by MAPLE, as shown by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) microscopy. A decrease of P-O and amide absorbance bands was observed as a consequence of different Zn2+ amounts. A variety of structural modifications of the apatite layer are then generated, which influenced the confinement process towards the collagen template. The in-vitro Simulated Body Fluid (SBF) assay demonstrated the ability of Coll/Zn2+-CaPs coatings to stimulate the mineralization process as a result of synergic effects in the collagen-Zn2+ substituted apatite. For both deposition methods, the formation of droplets associated to the growth of CaPs particulates inside the collagen matrix was visualized. This supports the prospective behavior of MAPLE biomimetic coatings to induce mineralization, as an essential step of fast implant integration with vivid tissues.

Synthesis of Biomimetic Materials from Collagen and Hydroxyapatite

New approach is described to synthesis of biomimetic materials on the basis of hydroxyapatite particles and collagen suspension produced from fish-production wastes. A simultaneous joint in vitro precipitation yields partly mineralized collagen fibrils. The process is similar to the mineralization stage in the case of an in vivo formation of bone tissue. The method for synthesizing a collagen-hydroxyapatite biomimetic composite material can serve as a basis for obtaining materials for the regenerative medicine.

Immobilized carbonic anhydrase: preparation, characteristics and biotechnological applications.

Carbonic anhydrase (CA) is an essential metalloenzyme in living systems for accelerating the hydration and dehydration of carbon dioxide. CA-catalyzed reactions can be applied in vitro for capturing industrially emitted gaseous carbon dioxide in aqueous solutions. To facilitate this type of practical application, the immobilization of CA on or inside solid or soft support materials is of great importance because the immobilization of enzymes in general offers the opportunity for enzyme recycling or long-term use in bioreactors. Moreover, the thermal/storage stability and reactivity of immobilized CA can be modulated through the physicochemical nature and structural characteristics of the support material used. This review focuses on (i) immobilization methods which have been applied so far, (ii) some of the characteristic features of immobilized forms of CA, and (iii) biotechnological applications of immobilized CA. The applications described not only include the CA-assisted capturing and sequestration of carbon dioxide, but also the CA-supported bioelectrochemical conversion of CO2 into organic molecules, and the detection of clinically important CA inhibitors. Furthermore, immobilized CA can be used in biomimetic materials synthesis involving cascade reactions, e.g. for bone regeneration based on calcium carbonate formation from urea with two consecutive reactions catalyzed by urease and CA.

Microanalysis using surface modification and biphasic droplets

Conventional methods for the synthesis and analysis of chemical and biological materials often utilize homogeneous bulk environments or surface immobilization on a substrate. Homogeneous bulk environments, however, require large quantities of samples and reagents as well as significant effort to functionalize materials. Liquid–substrate interfaces can also pose problems because adsorption can hinder diffusion and reagent transport during bioanalyses, and sensitive materials, such as proteins, experience denaturation, or other types of deformation. Here, we describe the construction and use of droplet microenvironments created through a combination of surface modification, water-in-oil systems, and aqueous two-phase systems (ATPSs). This integration of an immobilization-free droplet microenvironment with liquid–liquid interfaces, material compartmentalization, directional reagent transport, and small volumes enables unique material functions. Specific examples include ATPS-assisted fabrication of functional microparticles for drug delivery, microscale determination of ATPS phase diagrams, dendritic self-assembly of semiconductive nanoparticles, multiplex immunoassays, and analysis of breast cancer cell migration. Intracellular structures and function are tightly interwoven. Recapitulation of such intracellular microenvironments may enable novel biomimetic material synthesis and bioanalysis. Cell-inspired microanalysis platforms can be constructed by combined top-down microfabrication and bottom-up molecular self-assembly. Microcompartments of phase-separated aqueous solutions also play a critical role in biological processes. The biphasic microdroplets provide a unique analytical platform that conventional homogeneous bulk environments fail to achieve.

The open-cubane oxo-oxyl coupling mechanism dominates photosynthetic oxygen evolution: a comprehensive DFT investigation on O-O bond formation in the S4 state.

The dioxygen formation mechanism of biological water oxidation in nature has long been the focus of argument; many diverse mechanistic hypotheses have been proposed. Based on a recent breakthrough in the resolution of the electronic and structural properties of the oxygen-evolving complex in the S3 state, our density functional theory (DFT) calculations reveal that the open-cubane oxo-oxyl coupling mechanism, whose substrates preferably originate from W2 and O5 in the S2 state, emerges as the best candidate for O-O bond formation in the S4 state. This is justified by the overwhelming energetic superiority of this mechanism over alternative mechanisms in both the isomeric open and closed-cubane forms of the Mn4CaO5 cluster; spin-dependent reactivity rooted in variable magnetic couplings was found to play an essential role. Importantly, this oxygen evolution mechanism is supported by the recent discovery of femtosecond X-ray free electron lasers (XFEL), and the origin of the observed structural changes from the S1 to S3 state has been analyzed. In this view, we corroborate the proposed water binding mechanism during S2-S3 transition and correlate the theoretical models with experimental findings from aspects of substrate selectivity according to water exchange kinetics. This theoretical consequence for native metalloenzymes may serve as a significant guide for improving the design and synthesis of biomimetic materials in the field of photocatalytic water splitting.

Combinatorial microfluidic droplet engineering for biomimetic material synthesis

Although droplet-based systems are used in a wide range of technologies, opportunities for systematically customizing their interface chemistries remain relatively unexplored. This article describes a new microfluidic strategy for rapidly tailoring emulsion droplet compositions and properties. The approach uses a simple platform for screening arrays of droplet-based microfluidic devices and couples this with combinatorial selection of the droplet compositions. Through the application of genetic algorithms over multiple screening rounds, droplets with target properties can be rapidly generated. The potential of this method is demonstrated by creating droplets with enhanced stability, where this is achieved by selecting carrier fluid chemistries that promote titanium dioxide formation at the droplet interfaces. The interface is a mixture of amorphous and crystalline phases, and the resulting composite droplets are biocompatible, supporting in vitro protein expression in their interiors. This general strategy will find widespread application in advancing emulsion properties for use in chemistry, biology, materials, and medicine.

The chemical reactivities of DOPA and dopamine derivatives and their regioselectivities upon oxidative nucleophilic trapping

The chemical reactivities of four catecholamines, N-acetyl dopamine (NADA) and its dehydro derivative (NAΔDA), N-acetyl 3,4-dihydroxy-phenylalanine methyl ester (NADOPAME) and its dehydro derivative (NAΔDOPAME), under oxidative nucleophilic trapping and polymerisation conditions were compared and contrasted. Despite their structural similarities, varying reactivities and regioselectivities for oxidative nucleophilic trapping with ethanethiol were observed. This has possible implications on the use of these natural building blocks and their derivatives in the design and synthesis of biomimetic materials.

Amelogenin Affects Brushite Crystal Morphology and Promotes Its Phase Transformation to Monetite.

Amelogenin protein is involved in organized apatite crystallization during enamel formation. Brushite (CaHPO4·2H2O), one of the precursors of hydroxyapatite mineralization in vitro, has been used for fabrication of biomaterials for hard tissue repair. In order to explore its potential application in biomimetic material synthesis, we studied the influence of the enamel protein amelogenin on brushite morphology and phase transformation to monetite. Our results show that amelogenin can adsorb onto the surface of brushite, leading to the formation of layered morphology on the (010) face. Amelogenin promoted the phase transformation of brushite into monetite (CaHPO4) in the dry state, presumably by interacting with crystalline water layers in brushite unit cells. Changes to the crystal morphology mediated by amelogenin continued even after the phase transformation from brushite to monetite, leading to the formation of organized platelets with an interlocked structure. This effect of amelogenin on brushite morphology and the phase transformation to monetite could provide a new approach to developing biomimetic materials.

Predicting the Structure–Activity Relationship of Hydroxyapatite-Binding Peptides by Enhanced-Sampling Molecular Simulation

Understanding the molecular structural and energetic basis of the interactions between peptides and inorganic surfaces is critical to their applications in tissue engineering and biomimetic material synthesis. Despite recent experimental progresses in the identification and functionalization of hydroxyapatite (HAP)-binding peptides, the molecular mechanisms of their interactions with HAP surfaces are yet to be explored. In particular, the traditional method of molecular dynamics (MD) simulation suffers from insufficient sampling at the peptide-inorganic interface that renders the molecular-level observation dubious. Here we demonstrate that an integrated approach combining bioinformatics, MD, and metadynamics provides a powerful tool for investigating the structure-activity relationship of HAP-binding peptides. Four low charge density peptides, previously identified by phage display, have been considered. As revealed by bioinformatics and MD, the binding conformation of the peptides is controlled by both the sequence and the amino acid composition. It was found that formation of hydrogen bonds between lysine residue and phosphate ions on the surface dictates the binding of positively charged peptide to HAP. The binding affinities of the peptides to the surface are estimated by free energy calculation using parallel-tempering metadynamics, and the results compare favorably to measurements reported in previous experimental studies. The calculation suggests that the charge density of the peptide primarily controls the binding affinity to the surface, while the backbone secondary structure that may restrain side chain orientation toward the surface plays a minor role. We also report that the application of enhanced-sampling metadynamics effects a major advantage over the steered MD method by significantly improving the reliability of binding free energy calculation. In general, our novel integration of diverse sampling techniques should contribute to the rational design of surface-recognition peptides in biomedical applications.

Surface-Directed Assembly of Sequence-Defined Synthetic Polymers into Networks of Hexagonally Patterned Nanoribbons with Controlled Functionalities.

The exquisite self-assembly of proteins and peptides in nature into highly ordered functional materials has inspired innovative approaches to the design and synthesis of biomimetic materials. While sequence-defined polymers hold great promise to mimic proteins and peptides for functions, controlled assembly of them on surfaces still remains underdeveloped. Here, we report the assembly of 12-mer peptoids containing alternating acidic and aromatic monomers into networks of hexagonally patterned nanoribbons on mica surfaces. Ca(2+)-carboxylate coordination creates peptoid-peptoid and peptoid-mica interactions that control self-assembly. In situ atomic force microscopy (AFM) shows that peptoids first assemble into discrete nanoparticles; these particles then transform into hexagonally patterned nanoribbons on mica surfaces. AFM-based dynamic force spectroscopy studies show that peptoid-mica interactions are much stronger than peptoid-peptoid interactions, illuminating the driving forces for mica-directed peptoid assembly. We further demonstrate the display of functional domains at the N-terminus of assembling peptoids to produce extended networks with similar hierarchical structures. This research demonstrates that surface-directed peptoid assembly can be used as a robust platform to develop biomimetic coating materials for applications.

Unique morphology and gradient arrangement of nacre's platelets in green mussel shells.

Nacre has long served as a classic model in biomineralization and the synthesis of biomimetic materials. However, the morphology and arrangement of its basic building blocks, the aragonite platelets, are still under hot debate. In this study, using a field emission scanning electron microscope (SEM), a high-resolution transmission electron microscope (HRTEM), and an X-ray diffractometer (XRD), we investigate the platelets at the edges and centers of green mussel shells. We find that 1) flat and curved platelets coexist in green mussel shells; 2) the immature platelets at the shell edge are aggregates of aragonite nanoparticles, whereas the immature ones at the shell center are single crystals; and 3) the morphology and thickness of the platelets exhibit a gradient arrangement. Based on these findings, we hypothesize that the gradient in the thickness and curvature of the platelets may probably result from the difference in growth rate between the edge and the center of the shell and from the gradient in compressive stress imposed by the closing of the shells by the adductor muscles or the withdrawal of the periostracum by the mantle. We expect that the presented results will shed new light on the formation mechanisms of natural composite materials.

Tunable assembly of heterogeneously charged colloids.

The self-assembly of colloidal particles is a route to designed materials production that combines high flexibility, cost effectiveness, and the opportunity to create ordered structures at length scales ranging from nano- to micrometers. For many practical applications in electronics, photovoltaics, and biomimetic material synthesis, ordered mono- and bilayers are often needed. Here we present a novel and simple way to tune via external parameters the ordering of heterogeneously charged colloids into quasi two-dimensional structures. Depending on the charges of the underlying substrate and of the particles, a rich and versatile assembly scenario takes place, resulting from the complex interplay between directional attractive and repulsive particle–particle and particle–substrate interactions. Upon subtle variations of the relative charge of the system components, emerging via pH modification, reversible changes either from extended aggregates to a monomeric phase or from triangular to square domains are observed.

Facile functionalization of polypeptides by thiol-yne photochemistry for biomimetic materials synthesis

Rapid and highly efficient side-chain functionalization of polypeptides was achieved via combination of ring-opening polymerization of a new clickable monomer of γ-propargyl-L-glutamate N-carboxyanhydride (PLG-NCA) and thiol-yne photochemistry, which provides a convenient and universal route to prepare diverse polypeptide-based biomimetic hybrid materials.

The incorporation of GALA peptide into a protein cage for an acid-inducible molecular switch

Caged proteins have been utilized as a biological container in a wide range of applications from material science to biomedicine, and GALA peptide has been known to undergo coil-to-helix transition upon the increased acidity. In this study, GALA synthetic peptide is incorporated to cage protein by genetic modification. Our engineered caged scaffold retains intact at the physiological pH but dissociate completely at pH 6.0, and the dissociated subunits are re-assembled simply by neutralization to biological pH. This acid-induced dissociation has the potential as molecular switch in vivo as well as in vitro so that the acid-sensitive caged proteins are applicable to drug delivery system for acidic target sites such as tumor. Since our design depends on the conformational transition of GALA peptide, not on removal of characteristic interface observed only in viral capsid-like protein, non-viral caged proteins can also be engineered to have molecular switching function. Therefore, this design for acid-sensitive scaffold would broaden the width of applications in nanotechnology including biomimetic material synthesis and biomedicine.

Directing the Structure of Metal–Organic Frameworks by Oriented Surface Growth on an Organic Monolayer

The concept of biomineralization implies control of crystallization in terms of phase and orientation through interactions with organic macromolecules. This is of particular interest for the synthesis of biomimetic materials. If one strives to mimic the enormous structure-directing power of biomineralization in materials science, an artificial organic interface is needed. For example, functionalized self-assembled monolayers (SAMs) have been shown to effect oriented growth and phase direction of dense-phase calcium carbonate. The oriented growth of other dense materials such as lead sulfide and zinc oxide, and even the oriented growth of porous materials such as zeolites, on SAMs has been reported. Studies on the growth of MOF-5 and HKUST-1 phases on organic monolayers were recently reported. However, to our knowledge, so far it has not been possible to control the crystal structure of a porous material through interactions with molecular layers. This is expected to be particularly difficult due to the large, complex unit cells of these systems. Herein we present a dramatic change in the crystallization of a porous metal–organic framework on moving from homogeneous nucleation to heterogeneous nucleation on an ordered SAM. Due to their many potential applications such as gas sorption, molecular separation, storage, and catalysis, metal– organic frameworks (MOFs) have been intensively studied. We have recently reported the tunable, oriented growth of the porous MOF HKUST-1 on different functionalized SAMs. Herein we investigate the crystal growth of MOFs on mercaptohexadecanoic acid (MHDA) SAMs in the system Fe/bdc (bdc= 1,4-benzenedicarboxylic acid or terephthalic acid). In this system several open-framework structures are known, includingMIL-53 andMIL-88. The structures of MIL53 and MIL-88 are very flexible, and the cell constants of these materials are strongly dependent on pore content. The framework flexibility of these materials enables their use for adsorption of different organic molecules and makes them interesting candidates for sensors. In the monoclinic structure of Fe(OH)(bdc)(py)0.85, the Fe analogue of MIL-53, chains of FeO6 octahedra are connected by benzenedicarboxylate anions. Thus, rhombshaped one-dimensional (1D) channels are formed that run along the a axis of the structure. The hexagonal 3D structure of MIL-88B is built up from trimers of FeO6 octahedra linked to benzenedicarboxylate anions. Thus, the 3D pore system of MIL-88B consists of tunnels along the c axis connected by bipyramidal cages (Scheme 1).