David Kisailus - Academia.edu (original) (raw)

Papers by David Kisailus

Journal of Functional Biomaterials

A fine control over different dimensional scales is a challenging target for material science sin... more A fine control over different dimensional scales is a challenging target for material science since it could grant control over many properties of the final material. In this study, we developed a multivariable additive manufacturing process, direct ink write printing, to control different architectural features from the nano- to the millimeter scale during extrusion. Chitin-based gel fibers with a water content of around 1500% were obtained extruding a polymeric solution of chitin into a counter solvent, water, inducing instant solidification of the material. A certain degree of fibrillar alignment was achieved basing on the shear stress induced by the nozzle. In this study we took into account a single variable, the nozzle’s internal diameter (NID). In fact, a positive correlation between NID, fibril alignment, and mechanical resistance was observed. A negative correlation with NID was observed with porosity, exposed surface, and lightly with water content. No correlation was obse...

International Journal of Molecular Sciences

Biomineralization is an elaborate process that controls the deposition of inorganic materials in ... more Biomineralization is an elaborate process that controls the deposition of inorganic materials in living organisms with the aid of associated proteins. Magnetotactic bacteria mineralize magnetite (Fe3O4) nanoparticles with finely tuned morphologies in their cells. Mms6, a magnetosome membrane specific (Mms) protein isolated from the surfaces of bacterial magnetite nanoparticles, plays an important role in regulating the magnetite crystal morphology. Although the binding ability of Mms6 to magnetite nanoparticles has been speculated, the interactions between Mms6 and magnetite crystals have not been elucidated thus far. Here, we show a direct adsorption ability of Mms6 on magnetite nanoparticles in vitro. An adsorption isotherm indicates that Mms6 has a high adsorption affinity (Kd = 9.52 µM) to magnetite nanoparticles. In addition, Mms6 also demonstrated adsorption on other inorganic nanoparticles such as titanium oxide, zinc oxide, and hydroxyapatite. Therefore, Mms6 can potentially...

Journal of Materials Research and Technology, 2020

Biologically composites offer inspiration for the design of next generation structural materials ... more Biologically composites offer inspiration for the design of next generation structural materials due to their hierarchical microstructure that allows for, low density, and combination of high stiffness and toughness, currently unmatched by engineering technologies. Here, we investigate biomimetic composite materials that feature the laminated helicoidal architecture of fibers characteristic of the arthropod cuticle, specific to the mantis shrimp, but utilize either glass or Kevlar fibers, with epoxy or urethane matrix materials, to examine their role in impact energy dissipation. Drop weight impact test revealed epoxymatrix composites exhibited the highest peak load on impact and showed larger degrees of external damage such as delamination and fiber breakage as compared to the urethanebased composites. Moreover, the helicoidal panels, showed a significant reduction in dent depth and better residual compressive strength as compared to the quasi-isotropic design. These findings provide useful insight into the variation of reinforcement and matrix materials for the helicoidal architecture and how it affects the delocalization of damage and improves residual strength.

Additional file 1. Supplementary Information

Small Structures, 2022

Biological organisms naturally synthesize complex, hierarchical, multifunctional materials throug... more Biological organisms naturally synthesize complex, hierarchical, multifunctional materials through mineralization processes at ambient conditions and under physiological pH. One such example is the ultrahard and wear‐resistant radular teeth found in mollusks, which are used to scape against the rock to feed on algae. Herein, the biologically controlled structural development of the hard, outer magnetite‐containing shell of the chitin teeth is revealed. Specifically, the formation of a series of mesocrystalline iron oxide phases, templated by chitin‐binding proteins, is identified. The initial domains, consisting of ferrihydrite mesocrystals with a spherulite‐like morphology, undergo a solid‐state phase transformation to form magnetite while maintaining mesocrystallinity, likely via a shear‐induced solid‐state reaction, without any noticeable architectural changes. Subsequent growth via Ostwald ripening leads to nearly single‐crystalline rod‐like elements. In addition, an interpenetrating organic matrix is identified that, at early stages of tooth development, potentially contains iron‐binding proteins that guide the self‐assembly of the mesocrystalline mineral and influence the preferred orientation of the later‐formed magnetite nanorods, which ultimately determines the mechanical behavior of the mature chiton teeth.

Biological Magnetic Materials and Applications, 2018

The denticle caps of chiton teeth exhibit the largest hardness and stiffness among any biological... more The denticle caps of chiton teeth exhibit the largest hardness and stiffness among any biological minerals in the world. They consist of a composite structure of highly oriented crystalline nanorods of magnetite surrounded by a veneer of organic. The ultrahard teeth of the chiton are the first reported example of biologically formed magnetite, and its formation mechanisms have been of great interest to researchers for decades. Recently, using modern nanomechanical characterization techniques, it was shown that chiton teeth exhibit the largest hardness and stiffness of any biological mineral. The predicted abrasion resistance of chiton teeth against a blunt contact was reported to be even higher than that of zirconia. Therefore, the elucidation of chiton teeth synthetic processes could help us learn how to develop novel abrasion-resistant materials and environmentally benign processes for the production of iron oxides and other nanostructured materials. In order to understand the chiton teeth formation, proteomic analyses of tooth proteins as well as detailed structural analyses of mature and developing teeth were conducted. Based on the results obtained from these analyses, we discuss the underlying mechanisms of iron oxide biomineralization in chiton teeth.

: The research goal of this project is to study and understand the structure-function relationshi... more : The research goal of this project is to study and understand the structure-function relationships in damage-tolerant impact/shockresistant stomatopod dactyl club while addressing the ongoing quest to develop the new generation of scalable high-performance biologically-inspired multifunctional materials. Our ultrastructural investigations have identified that within this multi-regional composite structure, specific regions play very specific roles. We uncovered structural details from the striated region, which exists on the sides of the club. Unidirectional mineralized fibers in this region wrap circumferentially around the club, keeping it under compression during impact and preventing crack growth. To confirm this, we produced new models at multiple length scales and across length scales to show the effects of this outer layer. We compared this to the spearing dactyl of another species of mantis, in which this striated region is located on all sides (supporting flexural loads). ...

Biotechnology for Biofuels, 2021

Background Conventional aqueous dilute sulfuric acid (DSA) pretreatment of lignocellulosic biomas... more Background Conventional aqueous dilute sulfuric acid (DSA) pretreatment of lignocellulosic biomass facilitates hemicellulose solubilization and can improve subsequent enzymatic digestibility of cellulose to fermentable glucose. However, much of the lignin after DSA pretreatment either remains intact within the cell wall or readily redeposits back onto the biomass surface. This redeposited lignin has been shown to reduce enzyme activity and contribute to rapid enzyme deactivation, thus, necessitating significantly higher enzyme loadings than deemed economical for biofuel production from biomass. Results In this study, we demonstrate how detrimental lignin redeposition on biomass surface after pretreatment can be prevented by employing Co-solvent Enhanced Lignocellulosic Fractionation (CELF) pretreatment that uses THF–water co-solvents with dilute sulfuric acid to solubilize lignin and overcome limitations of DSA pretreatment. We first find that enzymatic hydrolysis of CELF-pretreated...

Proceedings of the National Academy of Sciences, 2020

Algal Research, 2020

This study investigates UV irradiation-induced cell settling, followed by cell aggregation, of th... more This study investigates UV irradiation-induced cell settling, followed by cell aggregation, of the oleaginous diatom Fistulifera solaris. Cell settling was observed after 24 h of cultivation following UV irradiation. The highest cell settling rate was obtained at a light intensity of 10 mJ/cm 2. The cell settling was induced by irradiating with UV (254 nm), but was ineffective with light of other wavelengths (474 or 620 nm). The settling response was not observed in other microalgae, such as Chlamydomonas reinhardtii and Phaeodactylum tricornutum, with the same treatment, suggesting that this response was specific to F. solaris. The optical and SEM images revealed the occurrence of cell aggregation with the UV treatment, resulting in the subsequent cell settling. Although there was no significant change in the lipid, protein, and sugar content, secreted acidic polysaccharide was found in the F. solaris cell culture following UV irradiation. Therefore, this polysaccharide was considered likely to be the cell aggregation-inducing factor. The energy consumption of this UV-induced cell settling for cell recovery method was estimated to be approximately 0.77 × 10 −1 kWh/m 3 , which is lower than the energy consumption of existing methods. Therefore, this method could be applied for harvesting F. solaris cells from large-scale cultures.

Small Methods, 2020

Iron biomineralisation is critical for life. Nature capitalises on the physical attributes of iro... more Iron biomineralisation is critical for life. Nature capitalises on the physical attributes of iron biominerals for a variety of functional, structural and sensory applications 1-5. Although magnetism is an integral property of iron biominerals, the role it plays in their nano-assembly remains a fundamental, unanswered question. This is well exemplified by the magnetite-bearing radula of chitons. Chitons, a class of marine mollusc, create the hardest biomineral of any animal in their abrasion-resistant, self-sharpening teeth 4. Despite this system being subjected to a range of high resolution imaging studies, the mechanisms that drive mineral assembly remain unresolved. However, the advent of quantum imaging technology provides a new avenue to probe magnetic structures directly. Here we use quantum magnetic microscopy 6 , based on nitrogen-vacancy centres in diamond, to attain the first subcellular magnetic profiling of a eukaryotic system. Using complementary magnetic imaging protocols, we spatially map the principal mineral phases (ferrihydrite and magnetite) in the developing teeth of Acanthopleura hirtosa with submicron resolution. The images reveal previously undiscovered long-range magnetic order, established at the onset of magnetite mineralisation. This is in contrast to electron microscopy studies that show no strong common crystallographic orientation 7. The quantum-based magnetic profiling techniques presented in this work have broad application in biology, earth science, chemistry and materials engineering and can be applied across the range of systems for which iron is vital.

Advanced Functional Materials, 2019

Mantis shrimp are aggressive marine crustaceans well known for their rapid and powerful hunting s... more Mantis shrimp are aggressive marine crustaceans well known for their rapid and powerful hunting strategies. Less well known, however, is the ability of some species of mantis shrimp to defend themselves from the repeated blows of conspecifics during ritualized fighting using a shield-like segment of abdominal armor called the telson. Multiscale structure-mechanical property relationships of this damage-tolerant biological composite is examined in order to reveal strategies that nature uses for resisting failure from repeated high-energy impacts. The telson structures of the smashingtype species, Odontodactylus scyllarus, and the less aggressive spearing-type species, Lysiosquillina maculata, are compared in order to better understand the ecological pressures driving the formation and use of the telson as a biological shield. A higher bulk compressive stiffness is identified within the smasher telson, which is attributed to its concave macromorphology, thicker cuticle, and higher degree of mineralization within its exocuticle. The presence of ridges at the dorsal surface suggests a role in imparting compliance for energy absorption. Fracture analysis identifies an enhanced toughening mechanism of crack twisting within the smasher telson, attributed to its well-defined pitch-graded helicoidal fibrous micro-architecture. Such findings may prove useful for the design of lightweight composite materials with potential flexibility and improved damage tolerance.

Small (Weinheim an der Bergstrasse, Germany), Jan 22, 2018

Carbon-based nanocomposites have shown promising results in replacing commercial Pt/C as high-per... more Carbon-based nanocomposites have shown promising results in replacing commercial Pt/C as high-performance, low cost, nonprecious metal-based oxygen reduction reaction (ORR) catalysts. Developing unique nanostructures of active components (e.g., metal oxides) and carbon materials is essential for their application in next generation electrode materials for fuel cells and metal-air batteries. Herein, a general approach for the production of 1D porous nitrogen-doped graphitic carbon fibers embedded with active ORR components, (M/MOx , i.e., metal or metal oxide nanoparticles) using a facile two-step electrospinning and annealing process is reported. Metal nanoparticles/nanoclusters nucleate within the polymer nanofibers and subsequently catalyze graphitization of the surrounding polymer matrix and following oxidation, create an interconnected graphite-metal oxide framework with large pore channels, considerable active sites, and high specific surface area. The metal/metal oxide@N-doped...

Biological systems offer examples of efficient strategies for the controlled synthesis of nanostr... more Biological systems offer examples of efficient strategies for the controlled synthesis of nanostructures to achieve desired properties. TiO2 is an inexpensive semiconducting material with widespread applications in self-cleaning coatings, photocatalysts and photovoltaics. In this work, we will be optimizing TiO2 nanowires for application in photovoltaics. TiO2 semiconductors can be made more efficient and useful by increasing the surface area to volume ratio while maintaining crystallinity. This ratio can be improved through fabrication of branched nanowires. Solvothermal synthesis directed by functional organic materials allows greater control over size and morphology. Modification of synthesis conditions (i.e., precursor concentration, pH and organic moieties) leads to the formation of highly branched TiO2 nanostructures. SEM images show nanowires 100-300 nm in diameter. These are actually nanowire bundles composed of smaller single-crystal nanowires ~10 nm in diameter, confirmed ...

Crystal Growth & Design, 2013

Understanding fundamental crystal nucleation and growth mechanisms is critical for producing mate... more Understanding fundamental crystal nucleation and growth mechanisms is critical for producing materials with controlled size and morphological features and uncovering structure−function relationships in these semiconducting oxides. Under hydro-solvothermal conditions, uniform branched and spherulitic TiO 2 rutile nanostructures were formed via (101) twins. On the basis of detailed, highresolution scanning electron microscopy and transmission electron microscopy analyses, we propose a mechanism of branched growth and the (101) twin formation via oriented attachment and subsequent transformation from anatase to rutile.

Crystal Growth & Design, 2015

Identifying the most appropriate polymorph of active pharmaceutical ingredients is one of the imp... more Identifying the most appropriate polymorph of active pharmaceutical ingredients is one of the important steps in drug development, since their bioactivities are largely dependent on their solid forms. However, the sample preparation for the characterization of crystal forms is time-consuming and requires large quantities of sample. Here, we introduce a microfluidic device-based method to prepare a sub-millimeter-sized single aspirin crystal from a small quantity of material. For the crystal preparation, a device equipped with a solution flow system and temperature controller was placed under the microscope. To use the device, concentration−temperature phase diagrams were generated, and regions where dominant nucleation or crystal growth with specific directions were clearly determined. By observing time-dependent changes of crystal number and size with solution temperature, a pathway to grow a single crystal of aspirin was determined and applied to prepare a submillimeter-sized crystal from 250 μg of aspirin. The obtained crystal was sufficiently large for single-crystal X-ray diffraction analysis, which usually requires 10 mg to 1 g of material per crystallization experiment. Thus, this method can be adapted as an efficient approach to uncovering the crystallization process to obtain required crystal forms with minimal sample consumption.