Die Autoren danken der Rowan University für die Unterstützung dieser Forschung. XH auch dank Dr. David L. Kaplan an der Tufts University und der NIH P41 Tissue Engineering Resource Center (TERC) für frühere technische Schulungen.

Keine Interessenskonflikte erklärt.

Einer der kritischsten Verfahren in der Herstellung von &quot;Legierung&quot; Proteinsystem ist, um die Mischbarkeit der gemischten Proteine ​​verifizieren. Ansonsten ist es nur eine nicht mischbare Mischung oder Protein-Protein-Verbundsystem ohne stabile und einstellbaren Eigenschaften. Eine experimentelle thermische Analyseverfahren kann für diesen Zweck verwendet werden und deren Legierungseigenschaften zu bestätigen. Protein-Protein-Interaktionen können nach der Flory-Huggins-Gittermodell 48, wie W...

Natur Strategien entwickelt, um abstimmbare und multifunktionale biologischen Matrices unter Verwendung einer begrenzten Anzahl von Strukturproteinen zu erzeugen. Beispielsweise Elastin und Kollagen werden immer zusammen in vivo verwendet werden, um die einstellbaren Stärken und Funktionen für spezifische Gewebe 1,2 erforderlich ist. Der Schlüssel zu dieser Strategie ist die Vermischung. Blending das Mischen Proteine ​​mit spezifischen Verhältnissen und ist ein technologischer Ansatz zur einfachen Materialsysteme mit einstellbaren Eigenschaften und abwechslungsreiches 3-5 zu generieren. Verglichen mit Kunsttechnik Strategien 6,7 können auch Misch verbessern Gleichförmigkeit Materials und die Fähigkeit, das Material aufgrund der einfachen Bedienung 8-16 verarbeiten. Daher Gestaltung multifunktional, biokompatible Proteinlegierungsmaterialien ist ein aufstrebendes Gebiet der medizinischen Forschung. Diese Technologie wird auch systematisches Wissen über die Auswirkungen der natürlichen Protein Matrizen auf Zell-und Gewebefunktionen sowohl in vitro und in vivo 10,17. Durch die Optimierung des Molekular Schnittstellen zwischen verschiedenen Proteine, Protein-basierten Legierungsmaterialien eine Reihe von Körperfunktionen, wie zum Beispiel thermische Stabilität bei verschiedenen Temperaturen, Elastizität, verschiedene Gewebe, elektrische Empfindlichkeit variabel Organe zu unterstützen und optische Eigenschaften für die Hornhautgeweberegeneration 3 umfassen, 18-27. Das Ergebnis dieser Studien wird eine neue Protein-Materialien-Plattform auf dem Gebiet der biomedizinischen Forschung mit direkter Relevanz für abstimmbare Gewebe repariert und Krankheitsbehandlungen und weitere führen zu biologisch abbaubaren Implantaten, wo ihre neue therapeutische und diagnostische Funktionen vorstellbar 3 werden kann. Viele natürliche Strukturproteine ​​haben kritische physikalische und bioaktiven Eigenschaften, die als Kandidaten für die Biomaterial-Matrizen ausgenutzt werden können. Seide aus verschiedenen Wurmarten, Keratine von Haaren und Wolle, Elastine und Kollagene aus verschiedenen Geweben undverschiedene Pflanzenproteine ​​sind einige der häufigsten Strukturproteinen für die Gestaltung variablen Materialien auf Proteinbasis (1), 18-27 verwendet. Im Allgemeinen können diese Proteine ​​unterschiedlichen Molekularsekundärstrukturen (zB Beta-Faltblätter für Seide, oder Spiralspulen für Keratine) aufgrund ihrer einzigartigen wiederholende primären Aminosäuresequenzen 3,28-35 bilden. Diese Eigenschaften fördern die Bildung von selbstorganisierten Strukturen makroskopischen mit einzigartigen Funktionen auf biologischen Schnittstellen aufgefordert ihre Nützlichkeit als wertvollen Ressource von Biopolymermaterialien. Hier sind zwei Arten von Strukturproteinen eingesetzt wurden (Protein A aus Wild Tussahseide und Protein B von domestizierten Maulbeerseide als Beispiel), die allgemeinen Protokolle der Herstellung von verschiedenen Protein-Legierung Biomaterialien zu demonstrieren. Die gezeigten Protokolle sind Teil 1: Protein-Interaktionsvorhersagen und Simulationen, Teil 2: Produktion von Protein-Legierung Lösungen und Teil 3: Herstellung von Protein-LegierungSysteme und für die optische, elektrische und pharmazeutische Anwendungen. <img alt="Figur 1" fo:content-width="5in" src="/files/ftp_upload/50891/50891fig1highres.jpg" width="500" /> Abbildung 1. Rohstoffe verschiedener Strukturproteine, die häufig in unserem Labor für die Gestaltung von Materialien auf Proteinbasis, einschließlich Seide aus verschiedenen Wurmarten verwendet werden, Keratine von Haaren und Wolle, Elastine aus verschiedenen Geweben und verschiedene Pflanzenproteine.

<table border="0" cellpadding="0" cellspacing="0" width="1050">
	<tbody>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">Q100 Differential Scanning Calorimeters (DSC)</td>
			<td style="width:143px;">TA Instruments, New Castle, DE, USA 
			&#160;</td>
			<td style="width:169px;">N/A</td>
			<td style="width:523px;">You can use any type of DSC with a software to calculate the heat capacity</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">SS30T Vacuum Sputtering System&#160;</td>
			<td style="width:143px;">T-M Vacuum Products, Inc., Cinnaminson, NJ, USA</td>
			<td style="width:169px;">N/A</td>
			<td>With custom built parts; You can use any type of sputtering system to coat</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">VWR 1415M Vacuum Oven&#160;</td>
			<td style="width:143px;">VWR International, Bridgeport, NJ, USA</td>
			<td style="width:169px;">N/A</td>
			<td>You can use any type of vacuum oven to physically crosslink the samples</td>
		</tr>
	</tbody>
</table>

designing silk-silk protein alloy materials for biomedical applications

Faserproteine ​​zeigen unterschiedliche Sequenzen und Strukturen, die für verschiedene Anwendungen in biomedizinischen Bereichen wie Biosensoren, Nanomedizin, Geweberegeneration und Drug-Delivery verwendet wurden. Entwicklung von Materialien auf der Basis der molekularen Maßstab Wechselwirkungen zwischen diesen Proteinen wird Ihnen helfen zu generieren neue multifunktionale Protein-Legierung Biomaterialien mit einstellbaren Eigenschaften. Solche Legierungsmaterial Systeme bieten auch Vorteile im Vergleich zu herkömmlichen synthetischen Polymeren durch die Materialien biologische Abbaubarkeit, Biokompatibilität und Haltbarkeit im Körper. Dieser Artikel verwendete die Proteinmischungen von Wild Tussahseide (Antheraea pernyi) und inländischen Maulbeerseide (Bombyx mori) als Beispiel, um nützliche Protokolle zu diesen Themen, darunter, wie Protein-Protein-Wechselwirkungen, die durch computergestützte Methoden, wie man Protein Legierung herzustellen vorherzusagen bieten Lösungen, wie Legierungssystemen durch thermische Analyse zu überprüfen, und zum variablen Legierungsmaterialien herzustelleneinschließlich der optischen Materialien mit Beugungsgitter, elektrische Materialien mit Schaltungen Beschichtungen und pharmazeutische Materialien für Drogenfreigabe und Auslieferung. Diese Methoden können wichtige Informationen für die Gestaltung der nächsten Generation multifunktionalen Biomaterialien auf der Basis verschiedener Protein-Legierungen bieten.

Typische Protein-Protein-Interaktionen (zB zwischen Protein A und Protein B) konnte Ladungs-Ladungs-(elektrostatische) Attraktionen, Wasserstoffbrücken Bildung, hydrophobe-hydrophile Wechselwirkungen sowie Dipol-, Lösungsmittel, Gegenionen und entropischen Effekte zwischen der spezifischen enthalten Domänen der beiden Proteine ​​(Abbildung 2) 3. Daher grundlegend, können wir die Effekte dieser Wechselwirkungen durch Computersimulationen vorherzusagen. <p class="jove_conte...

Watch this Scientific Journal Video about Designing Silk-silk Protein Alloy Materials for Biomedical Applications at JoVE.com

Designing Silk-silk Protein Alloy Materials for Biomedical Applications

Blending ist ein effizienter Ansatz zur Biomaterialien mit einem breiten Spektrum von Eigenschaften und Funktionen kombiniert erzeugen. Durch die Vorhersage der molekularen Wechselwirkungen zwischen verschiedenen natürlichen Seidenproteinen, können neue Seide-Seidenprotein-Legierung Plattformen mit einstellbaren mechanischen Elastizität, elektrische Antwort, optische Transparenz, chemische Verarbeitbarkeit, biologische Abbaubarkeit oder thermische Stabilität ausgelegt werden.

Gestaltung Silk-Seidenprotein-Legierungen für biomedizinische Anwendungen

Fibrous proteins display different sequences and structures that have been used for various applications in biomedical fields such as biosensors, ...

designing-silk-silk-protein-alloy-materials-for-biomedical

Research

JoVE Journal

Bioengineering

18.2K Aufrufe.  Rowan University.  Blending ist ein effizienter Ansatz zur Biomaterialien mit einem breiten Spektrum von Eigenschaften und Funktionen kombiniert erzeugen. Durch die Vorhersage der molekularen Wechselwirkungen zwischen verschiedenen natürlichen Seidenproteinen, können neue Seide-Seidenprotein-Legierung Plattformen mit einstellbaren mechanischen Elastizität, elektrische Antwort, optische Transparenz, chemische Verarbeitbarkeit, biologische Abbaubarkeit oder thermische Stabilität ausgeleg...

Serie: Designing Silk-silk Protein Alloy Materials for Biomedical Applications

Designing a Bio-responsive Robot from DNA Origami

Nucleic acids are astonishingly versatile. In addition to their natural role as storage medium for biological information1, they can be utilized in parallel computing2,3 , recognize and bind molecular or cellular targets4,5 , catalyze chemical reactions6,7 , and generate calculated responses in a biological system8,9. Importantly, nucleic acids can be programmed to self-assemble into 2D and 3D structures10-12, enabling the integration of all these remarkable features in a single robot linking the sensing of biological cues to a preset response in order to exert a desired effect.
Creating shapes from nucleic acids was first proposed by Seeman13, and several variations on this theme have since been realized using various techniques11,12,14,15 . However, the most significant is perhaps the one proposed by Rothemund, termed scaffolded DNA origami16. In this technique, the folding of a long (&gt;7,000 bases) single-stranded DNA 'scaffold' is directed to a desired shape by hundreds of short complementary strands termed 'staples'. Folding is carried out by temperature annealing ramp. This technique was successfully demonstrated in the creation of a diverse array of 2D shapes with remarkable precision and robustness. DNA origami was later extended to 3D as well17,18 .
 
The current paper will focus on the caDNAno 2.0 software19 developed by Douglas and colleagues. caDNAno is a robust, user-friendly CAD tool enabling the design of 2D and 3D DNA origami shapes with versatile features. The design process relies on a systematic and accurate abstraction scheme for DNA structures, making it relatively straightforward and efficient.
In this paper we demonstrate the design of a DNA origami nanorobot that has been recently described20. This robot is 'robotic' in the sense that it links sensing to actuation, in order to perform a task. We explain how various sensing schemes can be integrated into the structure, and how this can be relayed to a desired effect. Finally we use Cando21 to simulate the mechanical properties of the designed shape. The concept we discuss can be adapted to multiple tasks and settings.

DNA origami is a powerful method for fabricating precise nanoscale objects by programming the self-assembly of DNA molecules. Here, we describe how DNA origami can be utilized to design a robotic robot capable of sensing biological cues and responding by shape shifting, subsequently relayed to a desired effect.

Entwerfen einer Bio-responsive Robot von DNA Origami

Nucleic acids are astonishingly versatile. In addition to their natural role as storage medium for biological information1, they can be utilized in ...

Forschung

Biotechnik

Graphene Coatings for Biomedical Implants

Atomically smooth graphene as a surface coating has potential to improve implant properties. This demonstrates a method for coating nitinol alloys with nanometer thick layers of graphene for applications as a stent material. Graphene was grown on copper substrates via chemical vapor deposition and then transferred onto nitinol substrates. In order to understand how the graphene coating could change biological response, cell viability of rat aortic endothelial cells and rat aortic smooth muscle cells was investigated. Moreover, the effect of graphene-coatings on cell adhesion and morphology was examined with fluorescent confocal microscopy. Cells were stained for actin and nuclei, and there were noticeable differences between pristine nitinol samples compared to graphene-coated samples. Total actin expression from rat aortic smooth muscle cells was found using western blot. Protein adsorption characteristics, an indicator for potential thrombogenicity, were determined for serum albumin and fibrinogen with gel electrophoresis. Moreover, the transfer of charge from fibrinogen to substrate was deduced using Raman spectroscopy. It was found that graphene coating on nitinol substrates met the functional requirements for a stent material and improved the biological response compared to uncoated nitinol. Thus, graphene-coated nitinol is a viable candidate for a stent material.

Graphene offers potential as a coating material for biomedical implants. In this study we demonstrate a method for coating nitinol alloys with nanometer thick layers of graphene and determine how graphene may influence implant response.

Atomically smooth graphene as a surface coating has potential to improve implant properties. This demonstrates a method for coating nitinol alloys with ...

ECM Protein Nanofibers and Nanostructures Engineered Using Surface-initiated Assembly

The extracellular matrix (ECM) in tissues is synthesized and assembled by cells to form a 3D fibrillar, protein network with tightly regulated fiber diameter, composition and organization. In addition to providing structural support, the physical and chemical properties of the ECM play an important role in multiple cellular processes including adhesion, differentiation, and apoptosis. In vivo, the ECM is assembled by exposing cryptic self-assembly (fibrillogenesis) sites within proteins. This process varies for different proteins, but fibronectin (FN) fibrillogenesis is well-characterized and serves as a model system for cell-mediated ECM assembly. Specifically, cells use integrin receptors on the cell membrane to bind FN dimers and actomyosin-generated contractile forces to unfold and expose binding sites for assembly into insoluble fibers. This receptor-mediated process enables cells to assemble and organize the ECM from the cellular to tissue scales. Here, we present a method termed surface-initiated assembly (SIA), which recapitulates cell-mediated matrix assembly using protein-surface interactions to unfold ECM proteins and assemble them into insoluble fibers. First, ECM proteins are adsorbed onto a hydrophobic polydimethylsiloxane (PDMS) surface where they partially denature (unfold) and expose cryptic binding domains. The unfolded proteins are then transferred in well-defined micro- and nanopatterns through microcontact printing onto a thermally responsive poly(N-isopropylacrylamide) (PIPAAm) surface. Thermally-triggered dissolution of the PIPAAm leads to final assembly and release of insoluble ECM protein nanofibers and nanostructures with well-defined geometries. Complex architectures are possible by engineering defined patterns on the PDMS stamps used for microcontact printing. In addition to FN, the SIA process can be used with laminin, fibrinogen and collagens type I and IV to create multi-component ECM nanostructures. Thus, SIA can be used to engineer ECM protein-based materials with precise control over the protein composition, fiber geometry and scaffold architecture in order to recapitulate the structure and composition of the ECM in vivo.

A method to obtain nanofibers and complex nanostructures from single or multiple extracellular matrix proteins is described. This method uses protein-surface interactions to create free-standing protein-based materials with tunable composition and architecture for use in a variety of tissue engineering and biotechnology applications.

ECM-Protein-Nanofasern und Nanostrukturen Engineered Mit Oberflächen initiierte Versammlung

The extracellular matrix (ECM) in tissues is synthesized and assembled by cells to form a 3D fibrillar, protein network with tightly regulated fiber ...

Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial applications. Here we describe how electrospinning or electrospraying a polymer mixture containing a biodegradable, biocompatible aliphatic polyester (e.g., polycaprolactone and poly(lactide-co-glycolide)), as the major component, doped with a hydrophobic copolymer composed of the polyester and a stearate-modified poly(glycerol carbonate) affords a superhydrophobic biomaterial. The fabrication techniques of electrospinning or electrospraying provide the enhanced surface roughness and porosity on and within the fibers or the particles, respectively. The use of a low surface energy copolymer dopant that blends with the polyester and can be stably electrospun or electrosprayed affords these superhydrophobic materials. Important parameters such as fiber size, copolymer dopant composition and/or concentration, and their effects on wettability are discussed. This combination of polymer chemistry and process engineering affords a versatile approach to develop application-specific materials using scalable techniques, which are likely generalizable to a wider class of polymers for a variety of applications.

Two- and three-dimensional superhydrophobic polymeric materials are prepared by electrospinning or electrospraying biodegradable polymers blended with a lower surface energy polymer of similar composition.

Herstellung Superhydrophobe Polymere Materialien für biomedizinische Anwendungen

Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial ...

A Rapid and Quantitative Fluorimetric Method for Protein-Targeting Small Molecule Drug Screening

We demonstrate a new drug screening method for determining the binding affinity of small drug molecules to a target protein by forming fluorescent gold nanoclusters (Au NCs) within the drug-loaded protein, based on the differential fluorescence signal emitted by the Au NCs. Albumin proteins such as human serum albumin (HSA) and bovine serum albumin (BSA) are selected as the model proteins. Four small molecular drugs (e.g., ibuprofen, warfarin, phenytoin, and sulfanilamide) of different binding affinities to the albumin proteins are tested. It was found that the formation rate of fluorescent Au NCs inside the drug loaded albumin protein under denaturing conditions (i.e., 60 &#176;C or in the presence of urea) is slower than that formed in the pristine protein (without drugs). Moreover, the fluorescent intensity of the as-formed NCs is found to be inversely correlated to the binding affinities of these drugs to the albumin proteins. Particularly, the higher the drug-protein binding affinity, the slower the rate of Au NCs formation, and thus a lower fluorescence intensity of the resultant Au NCs is observed. The fluorescence intensity of the resultant Au NCs therefore provides a simple measure of the relative binding strength of different drugs tested. This method is also extendable to measure the specific drug-protein binding constant (KD) by simply varying the drug content preloaded in the protein at a fixed protein concentration. The measured results match well with the values obtained using other prestige but more complicated methods.

A protocol for small molecular drug screening based on in-situ synthesis of ultrasmall fluorescent gold nanoclusters (Au NCs) using drug-loaded protein as template is presented. This method is simple to determine the binding affinity of drugs to a target protein by a visible fluorescent signal emitted from the protein-templated Au NCs.

Eine schnelle und quantitative fluorimetrische Verfahren zur Protein-Targeting kleines Molekül als Wirkstoff-Screening

We demonstrate a new drug screening method for determining the binding affinity of small drug molecules to a target protein by forming fluorescent gold ...

Fabrication of Mechanically Tunable and Bioactive Metal Scaffolds for Biomedical Applications

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness and low bioactivity of metals. In this study, we have developed a new method towards fabricating a new type of bioactive and mechanically reliable porous metal scaffolds-densified porous Ti scaffolds. The method consists of two fabrication processes, 1) the fabrication of porous Ti scaffolds by dynamic freeze casting, and 2) coating and densification of the porous scaffolds. The dynamic freeze casting method to fabricate porous Ti scaffolds allowed the densification of porous scaffolds by minimizing the chemical contamination and structural defects. The densification process is distinctive for three reasons. First, the densification process is simple, because it requires a control of only one parameter (degree of densification). Second, it is effective, as it achieves mechanical enhancement and sustainable release of biomolecules from porous scaffolds. Third, it has broad applications, as it is also applicable to the fabrication of functionally graded porous scaffolds by spatially varied strain during densification.

Bioactive and mechanically reliable metal scaffolds have been fabricated through a method which consists of two processes, dynamic freeze casting for the fabrication of porous Ti, and coating and densification of the Ti scaffolds. The densification process is simple, effective and applicable to the fabrication of functionally graded scaffolds.

Herstellung von mechanisch Tunable und Bioactive Metallgerüste für biomedizinische Anwendungen

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness ...

The Synthesis of RGD-functionalized Hydrogels as a Tool for Therapeutic Applications

The use of polymers as biomaterials has provided significant advantages in therapeutic applications. In particular, the possibility to modify and functionalize polymer chains with compounds that are able to improve biocompatibility, mechanical properties, or cell viability allows the design of novel materials to meet new challenges in the biomedical field. With the polymer functionalization strategies, click chemistry is a powerful tool to improve cell-compatibility and drug delivery properties of polymeric devices. Similarly, the fundamental need of biomedicine to use sterile tools to avoid potential adverse-side effects, such as toxicity or contamination of the biological environment, gives rise to increasing interest in the microwave-assisted strategy.
The combination of click chemistry and the microwave-assisted method is suitable to produce biocompatible hydrogels with desired functionalities and improved performances in biomedical applications. This work aims to synthesize RGD-functionalized hydrogels. RGD (arginylglycylaspartic acid) is a tripeptide that can mimic cell adhesion proteins and bind to cell-surface receptors, creating a hospitable microenvironment for cells within the 3D polymeric network of the hydrogels. RGD functionalization occurs through Huisgen 1,3-dipolar cycloaddition. Some PAA carboxyl groups are modified with an alkyne moiety, whereas RGD is functionalized with azido acid as the terminal residue of the peptide sequence. Finally, both products are used in a copper catalyzed click reaction to permanently link the peptide to PAA. This modified polymer is used with carbomer, agarose and polyethylene glycol (PEG) to synthesize a hydrogel matrix. The 3D structure is formed due to an esterification reaction involving carboxyl groups from PAA and carbomer and hydroxyl groups from agarose and PEG through microwave-assisted polycondensation. The efficiency of the gelation mechanism ensures a high degree of RGD functionalization. In addition, the procedure to load therapeutic compounds or biological tools within this functionalized network is very simple and reproducible.

We present a protocol for the synthesis of RGD-functionalized hydrogels as devices for cell and drug delivery. The procedure involves copper catalyzed alkyne-azide cycloaddition (CuAAC) between alkyne-modified polyacrylic acid (PAA) and a RGD-azide derivative. The hydrogels are formed using microwave-assisted polycondensation and their physicochemical properties are investigated.

Die Synthese von RGD-funktionalisierten Hydrogele als Werkzeug für therapeutische Anwendungen

The use of polymers as biomaterials has provided significant advantages in therapeutic applications. In particular, the possibility to modify and ...

Light-mediated Formation and Patterning of Hydrogels for Cell Culture Applications

Click chemistries have been investigated for use in numerous biomaterials applications, including drug delivery, tissue engineering, and cell culture. In particular, light-mediated click reactions, such as photoinitiated thiol&#8722;ene and thiol&#8722;yne reactions, afford spatiotemporal control over material properties and allow the design of systems with a high degree of user-directed property control. Fabrication and modification of hydrogel-based biomaterials using the precision afforded by light and the versatility offered by these thiol&#8722;X photoclick chemistries are of growing interest, particularly for the culture of cells within well-defined, biomimetic microenvironments. Here, we describe methods for the photoencapsulation of cells and subsequent photopatterning of biochemical cues within hydrogel matrices using versatile and modular building blocks polymerized by a thiol&#8722;ene photoclick reaction. Specifically, an approach is presented for constructing hydrogels from allyloxycarbonyl (Alloc)-functionalized peptide crosslinks and pendant peptide moieties and thiol-functionalized poly(ethylene glycol) (PEG) that rapidly polymerize in the presence of lithium acylphosphinate photoinitiator and cytocompatible doses of long wavelength ultraviolet (UV) light. Facile techniques to visualize photopatterning and quantify the concentration of peptides added are described. Additionally, methods are established for encapsulating cells, specifically human mesenchymal stem cells, and determining their viability and activity. While the formation and initial patterning of thiol-alloc hydrogels are shown here, these techniques broadly may be applied to a number of other light and radical-initiated material systems (e.g., thiol-norbornene, thiol-acrylate) to generate patterned substrates.

We describe a sequential process for light-mediated formation and subsequent biochemical patterning of synthetic hydrogel matrices for three-dimensional cell culture applications. The construction and modification of hydrogels with cytocompatible photoclick chemistry is demonstrated. Additionally, facile techniques to quantify and observe patterns and determine cell viability within these hydrogels are presented.

Licht-vermittelte Bildung und Musterung von Hydrogelen für Zellkulturanwendungen

Click chemistries have been investigated for use in numerous biomaterials applications, including drug delivery, tissue engineering, and cell culture. In ...

Extraction of Plant-based Capsules for Microencapsulation Applications

Microcapsules derived from plant-based spores or pollen provide a robust platform for a diverse range of microencapsulation applications. Sporopollenin exine capsules (SECs) are obtained when spores or pollen are processed so as to remove the internal sporoplasmic contents. The resulting hollow microcapsules exhibit a high degree of micromeritic uniformity and retain intricate microstructural features related to the particular plant species. Herein, we demonstrate a streamlined process for the production of SECs from Lycopodium clavatum spores and for the loading of hydrophilic compounds into these SECs. The current SEC isolation procedure has been recently optimized to significantly reduce the processing requirements which are conventionally used in SEC isolation, and to ensure the production of intact microcapsules. Natural L. clavatum spores are defatted with acetone, treated with phosphoric acid, and extensively washed to remove sporoplasmic contents. After acetone defatting, a single processing step using 85% phosphoric acid has been shown to remove all sporoplasmic contents. By limiting the acid processing time to 30 hr, it is possible to isolate clean SECs and avoid SEC fracturing, which has been shown to occur with prolonged processing time. Extensive washing with water, dilute acids, dilute bases, and solvents ensures that all sporoplasmic material and chemical residues are adequately removed. The vacuum loading technique is utilized to load a model protein (Bovine Serum Albumin) as a representative hydrophilic compound. Vacuum loading provides a simple technique to load various compounds without the need for harsh solvents or undesirable chemicals which are often required in other microencapsulation protocols. Based on these isolation and loading protocols, SECs provide a promising material for use in a diverse range of microencapsulation applications, such as, therapeutics, foods, cosmetics, and personal care products.

This protocol/manuscript describes a streamlined process for the production of sporopollenin exine capsules (SECs) from Lycopodium clavatum spores and for the loading of hydrophilic compounds into these SECs.

Extraktion von Pflanzenbasis Kapseln für Mikroverkapselung Anwendungen

Microcapsules derived from plant-based spores or pollen provide a robust platform for a diverse range of microencapsulation applications. Sporopollenin ...

Rapid Mix Preparation of Bioinspired Nanoscale Hydroxyapatite for Biomedical Applications

Hydroxyapatite (HA) has been widely used as a medical ceramic due to its good biocompatibility and osteoconductivity. Recently there has been interest regarding the use of bioinspired nanoscale hydroxyapatite (nHA). However, biological apatite is known to be calcium-deficient and carbonate-substituted with a nanoscale platelet-like morphology. Bioinspired nHA has the potential to stimulate optimal bone tissue regeneration due to its similarity to bone and tooth enamel mineral. Many of the methods currently used to fabricate nHA both in the laboratory and commercially, involve lengthy processes and complex equipment. Therefore, the aim of this study was to develop a rapid and reliable method to prepare high quality bioinspired nHA. The rapid mixing method developed was based upon an acid-base reaction involving calcium hydroxide and phosphoric acid. Briefly, a phosphoric acid solution was poured into a calcium hydroxide solution followed by stirring, washing and drying stages. Part of the batch was sintered at 1,000 &#176;C for 2 h in order to investigate the products&#39; high temperature stability. X-ray diffraction analysis showed the successful formation of HA, which showed thermal decomposition to &#946;-tricalcium phosphate after high temperature processing, which is typical for calcium-deficient HA. Fourier transform infrared spectroscopy showed the presence of carbonate groups in the precipitated product. The nHA particles had a low aspect ratio with approximate dimensions of 50 x 30 nm, close to the dimensions of biological apatite. The material was also calcium deficient with a Ca:P molar ratio of 1.63, which like biological apatite is lower than the stoichiometric HA ratio of 1.67. This new method is therefore a reliable and far more convenient process for the manufacture of bioinspired nHA, overcoming the need for lengthy titrations and complex equipment. The resulting bioinspired HA product is suitable for use in a wide variety of medical and consumer health applications.

This paper describes a novel method for the rapid manufacture of high quality bioinspired nanoscale hydroxyapatite. This biomaterial is of great significance in the manufacture of a wide range of innovative medical devices for clinical applications in orthopedics, craniofacial surgery and dentistry.

Rapid-Mix Herstellung von Bioinspirierte Nanoskalige Hydroxyapatit für biomedizinische Anwendungen

Hydroxyapatite (HA) has been widely used as a medical ceramic due to its good biocompatibility and osteoconductivity. Recently there has been interest ...