Biological Composites Research Articles

Plastic strain localization in Bouligand structures

The Bouligand structure represents helicoidal stacking of aligned fibers; such a structure is widely observed in biological composites. Despite the progress in characterization of toughening caused by Bouligand arrangement of fibers, the inelastic deformation mechanisms of this structure remain elusive. In this study, we carry out calculations for plastic deformation of Bouligand structure, crossed-lamellar structure and the single lamellar structure. It is found that the single lamellar structure and crossed-lamellar structure can undergo necking, while in the Bouligand structure, plastic strain localization bands develop, which is accompanied by plastic rotating of fibers, lamellar twisting and lamellar delamination. Compared with crossed-lamellar structure, the Bouligand structure exhibits lower plastic energy dissipation. However, the Bouligand pattern can activate delamination of lamellae, generating high level of damage energy dissipation. The plastic deformation of Bouligand structure depends on the fracture properties of interface between adjacent lamellae. It is identified that the plastic dissipation of Bouligand structure increases with increasing cohesive strength of lamellar interface, and dominant shear bands emerge in the case of weak lamellar interface. The high strength of lamellar interface plays a role in promoting twisting of lamellae. We have further revealed the effect of the thickness of individual lamella on plastic deformation of the Bouligand structure. The thick lamella is capable of suppressing plastic strain localization in Bouligand structure, thereby giving rise to high plastic dissipation. The findings of this study shed new light on the development of bioinspired Bouligand-type materials.

Miscanthus floridulus-based intumescent flame retardant by green self-assembly for fully biological EP composites with commendable flame retardancy, smoke suppression and mechanical properties

The design of fully biological epoxy resin (EP) composites with high performance is highly desirable driven by green and sustainable development due to their renewable and sustainable nature. Herein, an efficient intumescent flame retardant based on Miscanthus floridulus (MF-based IFR) was devised for bio-epoxy composites by a green self-assembly method. The resulting composites with 15 wt% MF-based IFR demonstrated outstanding flame retardancy, effective smoke suppression, and favorable mechanical properties. The enhanced flame retardancy demonstrated the V-0 rating of UL-94 and the 26.4 % of limiting oxygen index (LOI) due to the dual-phase flame-retardant mechanism. Compared to pure EP, the EP composite with 15 wt% MF-based IFR exhibited reductions of 71.90 %, 61.85 %, 55.0 %, and 60.94 % in peak heat release rate (pHRR), total heat release rate (THR), smoke release rate (SPR), and smoke growth rate (TSP), respectively. Additionally, compared to unmodified MF, the composites with 15 wt% MF-based IFR displayed increasing of 3.35 %, 11.26 %, and 10.24 % in tensile, bending, and impact strengths, respectively, attributed to the enhanced interface compatibility. This study provides a straightforward, cost-effective, and efficient strategy for producing fully bio-based epoxy composites with high performance, expanding their potential applications.

Plant Fiber Composites for Biomedical Applications: Advances and Prospective.

Plant fibers are strong, robust, flexible, versatile, renewable, and sustainable, making them valuable for many applications. Fibers from plants are now utilized in biomedical applications as reinforcements for biological composites to enhance the mechanical characteristics of composite biological materials including rigidity, tensile strength, and endurance. Reinforcement composites with hybrid components were explored in biodevices for prospective utilization in orthopedics, prosthetics, tissue fabrication, and surgical dressings. This review presents an overview of plant fibers, including their characteristics, influencing variables, and numerous applications. The text explores several methods for creating synthetic composites using common, sustainable fibers and the distinct characteristics of the resulting biological materials. The text also analyses many instances of composite hybrids and their application in the biological field. The results are summarised and suggestions for potential improvements are presented. The current research primarily examines the concept, specifications, efficiency, and potential advancements of composites with hybrid characteristics made from plant fibers.

Preparation and characterization of microcrystalline cellulose from rice bran.

Rice bran, a by-product of rice processing, has not been fully utilized except for the small amount used for raising animals. The raw material source requirements of microcrystalline cellulose are becoming increasingly extensive. However, the characteristics of preparing microcrystalline cellulose from rice bran have not been reported, which limits the application of rice bran. Microcrystalline cellulose was obtained from rice bran by alkali treatment, delignification, bleaching and acid hydrolysis. The morphology, particle size distribution, degree of polymerization, crystallinity, and thermal stability of rice bran microcrystalline cellulose were analyzed. The chemical compositions, scanning electron microscopy and Fourier-transform infrared analysis for rice bran microcrystalline cellulose showed that the lignin and hemicellulose were successfully removed from the rice bran fiber matrix. The morphology of rice bran microcrystalline cellulose was shown to be of a short rod-shaped porous structure with an average diameter of 65.3 μm. The polymerization degree of rice bran microcrystalline cellulose was 150. The X-ray diffraction pattern of rice bran microcrystalline cellulose showed the characteristic peak of natural cellulose (type I), and its crystallization index was 71%. The rice bran microcrystalline cellulose may be used in biological composites with temperatures between 150 °C and 250 °C. These results suggest the feasibility of using rice bran as a low-price source of microcrystalline cellulose. © 2024 Society of Chemical Industry.

Fracture mechanics model of biological composites reinforced by helical fibers

Many biological materials such as tendons and muscles contain helical fibers. In this paper, the fracture behavior of such chiral composites is investigated through a combination of theoretical analysis and finite element simulations. A mesoscopic fracture mechanics model of helical fiber-reinforced biological composites is presented, with the effects of interfacial damage and fiber breakage. A cohesive law is adopted to characterize the interfacial damage induced by the relative slipping between the fibers and the matrix. The theoretical model agrees well with the numerical results. The optimized fiber radius that can maximize the fracture toughness of the composites is determined. The effects of interfacial (e.g., bonding strength and energy dissipation) and material properties (e.g., strength and elastic modulus) on the resistance to crack propagation are revealed. Our results show that the composites reinforced by helical fibers exhibit comprehensively excellent mechanical properties, e.g., simultaneous high strength, stiffness, and fracture toughness. This work not only helps understand the structure–property interrelations of biological chiral composites, but also provides inspirations for designing high-performance engineering materials.

On the isogeometric analysis of vibration and buckling of bioinspired composite plates using inverse hyperbolic shear deformation theory

Inspired by the remarkable energy absorption and damage tolerance capabilities observed in mantis shrimp crustaceans, this study delves into the intricate realm of biological composites with helicoidal structures. However, the effect of the relative orientation of fibers within the helicoidal structure matrix on the buckling and vibration characteristics still warrants comprehensive investigation for the better design of the bioinspired structures. For the first time, a Non-Uniform Rational B-Splines (NURBS)-based isogeometric analysis (IGA) framework termed NURBio is proposed to investigate the vibration and buckling characteristics of bioinspired laminated composite structures. The framework employs NURBS basis functions for exact complex geometric representation and field approximation and offers superior computational accuracy and efficiency as compared to conventional finite element method (FEM). The present analysis is underpinned by an inverse hyperbolic shear deformation theory (IHSDT) capable of accurately capturing the interlaminar stress distribution. This research investigates the performance of various bioinspired layup configurations encompassing recursive, exponential, semicircular, and Fibonacci helicoidal designs and compares them with those of unidirectional, and cross-ply laminates. A series of numerical examples on the buckling and vibration response of bioinspired composite plates are presented to demonstrate the versatility and efficacy of the proposed isogeometric framework. The influence of different layups, loading and boundary conditions, and geometric properties on the response of different bioinspired plate structures are meticulously examined. The study offers valuable insights into the design and optimization of high-performance bioinspired structures.

Buckling behaviors prediction of biological staggered composites with finite element analysis and machine learning coupled method

Staggered structure, where mineral crystals are arranged in a staggered manner in protein matrix, is the most representative microstructure in biological composites. Because of the elongated geometry and large aspect ratio of mineral crystals, their failure mechanism under compressive loading is predominantly controlled by buckling. The microstructural complexity, diversity of the constituent materials, and the complexity of buckling behaviors present substantial challenges for the precise forecasting of the buckling behavior of biological materials. In this paper, a novel method combining finite element analysis with machine learning is proposed. Specifically, based on the large dataset obtained using the finite element method, the buckling strength of biological staggered composites was rapidly predicted using a machine learning algorithm. Herein, the effects of microstructure and component materials on buckling behavior have been investigated systematically. The results indicate that the neural network models are highly accurate in predicting critical buckling strength. Aspect ratio and modulus ratio significantly affect the critical buckling strength of staggered structures according to the results of feature importance analysis. Additionally, the post-buckling modes of staggered structures exhibit heightened sensitivity to initial geometric defects, particularly in higher-order buckling modes. Our research provides valuable insights into fast and accurate prediction of the buckling behavior of biological composites and their design.

Simultaneous TG―FTIR studies show high thermal resilience in core organic matrix of molluscan gastropod shell of N. josephinia

Nacre—a biological composite of alternating layers of aragonite platelets and organic matrices, derived from biomaterials like molluscan shells has recently attracted a lot of interest as a potential substitute for ceramic material in orthopedic tissue engineering. It is formed as a result of interesting biomineralization processes. Molluscs use a striking variety of structural motifs to build their shells composed of calcium carbonate and a small percentage of proteins. These integral proteins determine the structural organization and properties of the mineralized composite. However, the composition and thermal stability of these proteinous matrices remains a mystery. Until now it was presumed that the organic matrix in a shell degrades completely up to 500 °C (stage―I). Stage―II comprises degradation of CaCO3 to CaO spanning about 600 °C to 850 °C. However, in case of a gastropod mollusc shell of Neverita josephinia, stage―III was also observed, in which majority weight loss of core organic proteinous matrix (OPM) exceeding 6 wt%, starts after about 1000 °C of thermal heating. It is observed that the core organic matrix (OM) has varied composition throughout the shell, stronger bonding, complex topology and has very high thermal resilience even up to 1400 °C. Simultaneous analysis of evolved gases by FTIR spectrometer coupled with thermogravimetric analyzer shows the composition of non-mineral species is more than 8 wt%. The results are supported by room temperature as well as gas phase by FTIR spectroscopy, XRD, SEM, CHNS analyses. The XRD spectra of the pristine shell powder and that calcined at 550 °C reveal aragonite to calcite phase transformation in calcium carbonate. The SEM shows the cross-lamellar morphology of the gastropod mollusk shell. There are two different sets of organic matrices: one with complex topology and a very tight binding to the mineral components (intra-crystalline), and the other with a loose binding to the mineral (inter-platelet area). Elemental analysis (CHNS) data, also supports this. This study identifies that the organic matrix, comprising proteins, peptides, lipids, and carbohydrates, exhibits complex topology and strong mineral bonding, contributing to the shell's notable mechanical strength and resistance to thermal degradation. The implications of this high thermal resilience for the shell's mechanical properties and potential biomineralization processes are discussed, suggesting a reevaluation of the organic matrix's role in molluscan shells.

Investigation of the interface of fungal mycelium composite building materials by means of low-vacuum scanning electron microscopy.

Low-vacuum scanning electron microscopy (low-vacuum SEM) is widely used for different applications, such as the investigation of noncoated specimen or the observation of biological materials, which are not stable to high vacuum. In this study, the combination of mineral building materials (concrete or clay plaster) with a biological composite (fungal mycelium composite) by using low-vacuum SEM was investigated. Fungal biotechnology is increasingly gaining prominence in addressing the challenges of sustainability transformation. The construction industry is one of the biggest contributors to the climate crises and, therefore, can highly profit from applications based on regenerative fungal materials. In this work, a fungal mycelium composite is used as alternative to conventional insulating materials like Styrofoam. However, to adapt bio-based products to the construction industry, investigations, optimisations and adaptations to existing solutions are needed. This paper examines the compatibility between fungal mycelium materials with mineral-based materials to demonstrate basic feasibility. For this purpose, fresh and hardened concrete specimens as well as clay plaster samples are combined with growing mycelium from the tinder fungus Fomes fomentarius. The contact zone between the mycelium composite and the mineral building materials is examined by scanning electron microscopy (SEM). The combination of these materials proves to be feasible in general. The use of hardened concrete or clay with living mycelium composite appears to be the favoured variant, as the hyphae can grow into the surface of the building material and thus a layered structure with a stable connection is formed. In order to work with the combination of low-density organic materials and higher-density inorganic materials simultaneously, low-vacuum SEM offers a suitable method to deliver results with reduced effort in preparation while maintaining high capture and magnification quality. Not only are image recordings possible with SE and BSE, but EDX measurements can also be carried out quickly without the influence of a coating. Depending on the signal used, as well as the magnification, image-recording strategies must be adapted. Especially when using SE, an image-integration method was used to reduce the build-up of point charges from the electron beam, which damages the mycelial hyphae. Additionally using different signals during image capture is recommended to confirm acquired information, avoiding misinterpretations.

Robust and sensitive conductive nanocomposite hydrogel with bridge cross-linking-dominated hierarchical structural design.

Conductive hydrogels have a remarkable potential for applications in soft electronics and robotics, owing to their noteworthy attributes, including electrical conductivity, stretchability, biocompatibility, etc. However, the limited strength and toughness of these hydrogels have traditionally impeded their practical implementation. Inspired by the hierarchical architecture of high-performance biological composites found in nature, we successfully fabricate a robust and sensitive conductive nanocomposite hydrogel through self-assembly-induced bridge cross-linking of MgB2 nanosheets and polyvinyl alcohol hydrogels. By combining the hierarchical lamellar microstructure with robust molecular B─O─C covalent bonds, the resulting conductive hydrogel exhibits an exceptional strength and toughness. Moreover, the hydrogel demonstrates exceptional sensitivity (response/relaxation time, 20 milliseconds; detection lower limit, ~1 Pascal) under external deformation. Such characteristics enable the conductive hydrogel to exhibit superior performance in soft sensing applications. This study introduces a high-performance conductive hydrogel and opens up exciting possibilities for the development of soft electronics.

Green production and analysis of silver nanoparticles utilizing Pathor Kuchi Leaf

Silver nanoparticles (Ag NPs) were manufactured utilizing Pathor Kuchi Leaf (PKL) extract in an environmentally, cost-effective green way. X-Ray Powder Diffraction (XRD), Fourier Transform Infrared (FTIR), Ultraviolet–Visible Spectroscopy (UV–Vis), and Scanning Electron Microscopy (SEM) have been used to look into Ag NPs generation. The crystalline structure was shown by the XRD pattern investigation, and its typical size is 19 nm. Its biological molecules composites are in charge of the diminishment and also the capping of Ag NPs, according to FTIR spectra. The UV–Vis spectra of silver NPs expressed a noticeably large absorption peak centered at ∼400 nm, which denoted the production of Ag0 from Ag+. After the distribution of sizes analysis, it must have been discovered that the mean dimension of the particles of the spherical silver nanoparticles in the SEM pictures was 5.33 µm. Ag NPs have been shown to potentially improve the power generation, short circuit current, and open circuit voltage of PKL bio-electrochemical cells. This work exhibits a straightforward, economical, and ecologically friendly way of manufacturing. The uniqueness of this work is that it is the first-ever comparative analysis of Ag NPs’ production utilizing PKL extract. The majority of the conclusions have been grouped and visually explained.

Mesoporous Composite Bioactive Compound Delivery System for Wound-Healing Processes.

Currently, the treatment of wounds is still a challenge for healthcare professionals due to high complication incidences and social impacts, and the development of biocompatible and efficient medicines remains a goal. In this regard, mesoporous materials loaded with bioactive compounds from natural extracts have a high potential for wound treatment due to their nontoxicity, high loading capacity and slow drug release. MCM-41-type mesoporous material was synthesized by using sodium trisilicate as a silica source at room temperature and normal pressure. The synthesized mesoporous silica was characterized by using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), N2 absorption-desorption (BET), Dynamic Light Scattering (DLS) and Fourier transform infrared spectroscopy (FT-IR), revealing a high surface area (BET, 1244 m2/g); pore diameter of approx. 2 nm; and a homogenous, ordered and hexagonal geometry (TEM images). Qualitative monitoring of the desorption degree of the Salvia officinalis (SO) extract, rich in ursolic acid and oleanolic acid, and Calendula officinalis (CO) extract, rich in polyphenols and flavones, was performed via the continuous recording of the UV-VIS spectra at predetermined intervals. The active ingredients in the new composite MCM-41/sage and marigold (MCM-41/SO&CO) were quantified by using HPLC-DAD and LC-MS-MS techniques. The evaluation of the biological composites' activity on the wound site was performed on two cell lines, HS27 and HaCaT, naturally involved in tissue-regeneration processes. The experimental results revealed the ability to stimulate collagen biosynthesis, the enzymatic activity of the main metalloproteinases (MMP-2 and MMP-9) involved in tissue remodeling processes and the migration rate in the wound site, thus providing insights into the re-epithelializing properties of mesoporous composites.

Nanoscale dynamic mechanical analysis on interfaces of biological composites

Biological composites incorporate structural arrays of rigid-elastic reinforcements made of minerals or crystalline biopolymers, which are connected by thin, compliant, and viscoelastic macromolecular matrix material. The near-interface regions of these biological composites grant them energy dissipation capabilities against dynamic mechanical loadings, which promote various biomechanical functions such as impact adsorption, fracture toughness, and mechanical signal filtering. Here, we employ theoretical modeling and finite-element simulations to analyze the mechanical response of the near-interface in biological composites to nanoscale dynamic mechanical analysis (DMA). We identified the dominating load-bearing mechanisms of the near-interface region and employed these insights to introduce simple semi-empirical formulations for approaching the mechanical properties (storage and loss moduli) of the biological composite from the nanoscale DMA results. Our analysis paves the way for the nanomechanical characterization of biological composites in diverse natural materials systems, which can also be employed for bioinspired and biomedical configurations.

Reviewing the Integrated Design Approach for Augmenting Strength and Toughness at Macro- and Micro-Scale in High-Performance Advanced Composites.

In response to the growing demand for high-strength and high-toughness materials in industries such as aerospace and automotive, there is a need for metal matrix composites (MMCs) that can simultaneously increase strength and toughness. The mechanical properties of MMCs depend not only on the content of reinforcing elements, but also on the architecture of the composite (shape, size, and spatial distribution). This paper focuses on the design configurations of MMCs, which include both the configurations resulting from the reinforcements and the inherent heterogeneity of the matrix itself. Such high-performance MMCs exhibit excellent mechanical properties, such as high strength, plasticity, and fracture toughness. These properties, which are not present in conventional homogeneous materials, are mainly due to the synergistic effects resulting from the interactions between the internal components, including stress-strain gradients, geometrically necessary dislocations, and unique interfacial behavior. Among them, aluminum matrix composites (AMCs) are of particular importance due to their potential for weight reduction and performance enhancement in aerospace, electronics, and electric vehicles. However, the challenge lies in the inverse relationship between strength and toughness, which hinders the widespread use and large-scale development of MMCs. Composite material design plays a critical role in simultaneously improving strength and toughness. This review examines the advantages of toughness, toughness mechanisms, toughness distribution properties, and structural parameters in the development of composite structures. The development of synthetic composites with homogeneous structural designs inspired by biological composites such as bone offers insights into achieving exceptional strength and toughness in lightweight structures. In addition, understanding fracture behavior and toughness mechanisms in heterogeneous nanostructures is critical to advancing the field of metal matrix composites. The future development direction of architectural composites and the design of the reinforcement and toughness of metal matrix composites based on energy dissipation theory are also proposed. In conclusion, the design of composite architectures holds enormous potential for the development of composites with excellent strength and toughness to meet the requirements of lightweight structures in various industries.

A novel method for depolarization tensor and average form of an arbitrarily shaped inclusion: Extension to different physical fields and their effective transport properties of composites

Depolarization tensor (DT), exclusively controlled by the inclusion shape, is crucial in assessing composite transport behavior. However, the solution of DT for a non-ellipsoidal inclusion exhibits nonuniformity and lacks a closed-form expression. Average DT is then introduced to ensure uniformity and seamlessly integrate the evaluation of effective transport properties of composites. In this work, we devise a novel method to obtain DT and average DT of an arbitrarily shaped inclusion by leveraging mathematical similarity from Greenʼs function to degenerate the Eshelby tensor and average Eshelby tensor in an elastic field. The method circumvents singularity and complexity in direct integration and successfully extracts all tensor components. As natural extensions, we also derive the Eshelby conduction tensor, polarizability tensor, and their averages. The accuracy of the method is validated by comparing the average polarizabilities of Platonic solids and stem cells with existing literature data. Furthermore, we incorporate average DT into a developed homogenization model to predict effective transport properties of two-phase composites comprising randomly distributed congruent irregular inclusions. Comparisons with finite element simulations demonstrate accurate predictions of the effective transport properties like effective permeability, diffusivity, conductivity, and permittivity. The proposed framework offers valuable guidance for tailoring inclusion shapes to design particulate/fibrous/porous/biological composites.

A micromechanical model for bioinspired nanocomposites with interphase

The stagger-aligned structures including ‘‘brick-and-mortar’’ are well-known as a generic feature in biological tough and strong nanocomposites, leading to bioinspired high-performance composites. Experimental observations have shown that the region between the stiff reinforcements and the soft matrices is not an interface of zero thickness but a nanoscale interphase. The interphases are believed to play an important role in the overall mechanical achievements; however, related theoretical models are still yet to be developed for decoding the interphase-related mechanisms. Based on the shear-lag theory, this work establishes a theoretical model for the staggered nanocomposites explicitly considering the interphase. In particular, a compact formula of the nanocomposites’ effective modulus (Ec) is derived, clearly showing the relations to a load-sustain dominant term (ER) and a term (ES) reflecting the load-transfer through shear deformation, as well as other microstructural and material parameters. With comparison to results by the finite element analysis and other existing relevant models, our model exhibits superior accuracy and simplicity, as well as general applicability. Furthermore, our model reveals an interesting working mechanism of the interphase: Ec is sensitive to the interphase properties for the shear transfer parameter (βII) being around 1.5–7.5, as the interphase undertakes both stress-transfer and stress-sustaining roles. The model and findings shed light on the role of the interphase in enhancing load-bearing biological composites and provide new insights in optimizing bioinspired nanocomposites through modulating the interphase properties.

Synthesis of nanosilver particles mediated by microbial surfactants and its enhancement of crude oil recovery

In view of the increasingly high demand for environmental protection in oil fields, new environmentally friendly materials that can replace harmful chemicals must be urgently studied. In this study, the biofriendly reducing agent “ascorbic acid” was selected to prepare nanosilver, and a biological nanosilver composite (Bio-Ag) was synthesized using the fermentation supernatants of Candida and P. aeruginosa, which were refrigerated in the laboratory as modifiers and dispersants. Furthermore, sand-filled pipe and micromodel oil displacement experiments were conducted. XRD results confirmed the formation of nanosilver, and its crystal structure was FCC. SEM results showed that the size of the nanosilver was 15–60 nm, and the shape was irregular ellipsoid, angular, or rod shaped. FT-IR results showed that microbial metabolism produced bioactive substances, such as glycolipids and peptides, which were modified on the surface of the nanoparticles. In the laboratory, displacement experiments of nanosilver dispersed by sodium dodecyl sulfate (SDS-Ag), Candida fermentation supernatant (C–Ag), and Pseudomonas aeruginosa (P–Ag) were conducted, and the oil recovery increased by 13.6%, 19.49%, and 11.4%，respectively. Results of the microdisplacement experiment showed that nanoparticles had strong adsorption capacity in the pore throat and had good stripping effect on residual oil.

Fast stress wave attenuation in bioinspired composites with distributed soft particles modulating hard matrices

Fast stress wave attenuation in composites is highly desired in many industry fields. Biological composites such as those in the beak of woodpeckers provide great inspiration for us to develop their synthetic counterparts with similar mechanical functions. Accordingly, bioinspired designs of composites with distributed soft particles are put forward in the paper, and their performance in attenuating stress wave is investigated through FEM simulations. Subjected to projectile impacts, the bioinspired composites not only absorb more impact energy but also delay and attenuate the impact-induced stress wave very efficiently. The simultaneous improvement of the two aspects of impact-resistant performance in a single material design should be highly desired in many industry fields. Further, the influences of the inclusion volume fraction, impedance, shape and distribution pattern are systematically investigated and general principles of design are drawn. The findings and conclusions can not only provide useful guidelines for the design of bioinspired composites with high protection function from impact loading but also help understand the working mechanisms of natural biological composites to resist impact loadings.

Fast extraction of three-dimensional nanofiber orientation from WAXD patterns using machine learning.

Structural disclosure of biological materials can help our understanding of design disciplines in nature and inspire research for artificial materials. Synchrotron microfocus X-ray diffraction is one of the main techniques for characterizing hierarchically structured biological materials, especially the 3D orientation distribution of their interpenetrating nanofiber networks. However, extraction of 3D fiber orientation from X-ray patterns is still carried out by iterative parametric fitting, with disadvantages of time consumption and demand for expertise and initial parameter estimates. When faced with high-throughput experiments, existing analysis methods cannot meet the real time analysis challenges. In this work, using the assumption that the X-ray illuminated volume is dominated by two groups of nanofibers in a gradient biological composite, a machine-learning based method is proposed for fast and automatic fiber orientation metrics prediction from synchrotron X-ray micro-focused diffraction data. The simulated data were corrupted in the training procedure to guarantee the prediction ability of the trained machine-learning algorithm in real-world experimental data predictions. Label transformation was used to resolve the jump discontinuity problem when predicting angle parameters. The proposed method shows promise for application in the automatic data-processing pipeline for fast analysis of the vast data generated from multiscale diffraction-based tomography characterization of textured biomaterials.

A Novel Composite Nano-scaffold with Potential Usage as Skin Dermo-epidermal Grafts for Chronic Wound Treatment

Background: Nano-scaffolds loaded with bioactive compounds such as ZnO nanoparticles (ZnO-NPs), as tissue-engineered artificial skin grafts, can be a suitable substitute for extracellular matrix and greatly contribute to accelerating chronic wound treatment by decreasing the chance of bacterial infection. Methods: Silk fibroin nanofiber was fabricated by using electrospinning and three-dimensional porous hybrids (3DPH) nano-scaffold with composite of sodium alginate/ZnO-NPs solution and silk fibroin electrospun nanofibers by adopting freeze-drying method. Successful configuration of nanofibers and porous nano-scaffolds were confirmed using field emission scanning electron microscopy (FE-SEM). Antimicrobial activity, cell attachment, and cytotoxicity evaluation of scaffolds were performed by employing disk diffusion method, L929 cell culture, and MTT assay, respectively. Results: Antibacterial analysis of 3DPH nano-scaffolds revealed their appropriate antibacterial activity against the Staphylococcus aureus and the Escherichia coli bacteria. Furthermore, the results from cytotoxicity and cell adhesion analyses indicated the appropriate cell attachment, viability, and proliferation on the silk fibroin nanofibers and 3DPH nano-scaffold, which are fundamental for wound healing and skin dermo-epidermal grafts. Conclusions: In sum, silk fibroin nanofiber as an epidermal graft and 3DPH nano-scaffold loaded with ZnO-NPs as a dermal graft were fabricated. Moreover, 1.5% (w/v) concentrations of ZnO-NPs were selected and incorporated into the 3DPH nano-scaffold. Considering the promising results of biological analyses, the nanofibrous and 3DPH nano-scaffolds composite may have been suitable for skin dermo-epidermal grafts and skin regeneration.