Ultrasound-assisted air-jet spinning of silk fibroin-soy protein nanofiber composite biomaterials.

Ultrasound utilizes a non-radiation technology that can meet modern standards to gain access to cheap, reliable and sustainable modern energy. Ultrasound technology can be implemented in the field of biomaterials for its exceptional potential in controlling the shape of nanomaterials. This study presents the first example of the production of soy and silk fibroin protein composite nanofibers in various ratios via combining ultrasonic technology with air-spray spinning. Characterization of ultrasonic spun nanofibers was performed by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, water contact angle, water retention, enzymatic degradation, and cytotoxicity assays. The effects that adjustments on the ultrasonic time have on the surface morphology, structures, thermal properties, hydrophilicity, water-uptake, bio-enzyme degradability, mechanical properties, and cytocompatibility of the material were examined. It was discovered that as the sonication time increased from 0 to 180 min, the beading phenomenon disappeared, forming nanofibers with uniform diameter and porosity; while the content of ß-sheet crystals in the composites and their thermal stability gradually increased, the materials glass transition temperature decreased, and preferred mechanical properties were obtained. Additional studies show that the hydrophilicity, water retention capacity and enzymatic degradation rate were also enhanced by ultrasound, providing a favorable environment for cell attachment and proliferation. This study highlights the experimental and theoretical methods for ultrasound assisted air-jet spinning of biopolymer nanofibrous materials with tunable properties and high biocompatibility, which provide a wide range of applications in wound dressings and drug-carrying systems. This work shows great potential for a direct road to sustainable development of protein based fibers in the industry, thus promoting economic growth, and improving the health of the general population and well-being of wounded patients worldwide.

Air-jet spun tissue engineering scaffolds incorporated with diamond nanosheets with improved mechanical strength and biocompatibility.

The development of highly porous cell supportive polymeric scaffolds with sufficient mechanical strength has always been a challenging task in tissue engineering. The widely used nanofiber fabrication methods like electrospinning are time consuming and the obtained nanofibrous scaffolds are generally consist of compactly packed fibers, which affect proper cell penetration. On the other hand, air-jet spinning is an upcoming, less explored alternative approach for generating loosely arranged nanofibrous scaffolds within short time. However, air-jet spun scaffolds show inferior mechanical properties due to loosely organized fibers. Herein, we report the fabrication and detailed characterization of polycaprolactone (PCL) tissue engineering scaffolds loaded with diamond nanosheets (DNS) by air-jet spinning. Our results showed that the inclusion of DNS could improve the mechanical strength of the scaffolds. In vitro biocompatibility, and in vivo implantation studies demonstrated that PCL-DNS scaffolds are highly biocompatible and are suitable for tissue engineering applications. Our studies showed that mammalian cells can proliferate well in the presence of PCL-DNS scaffolds and the nanocomposite scaffolds implanted in rats did not show any considerable adverse effects. Overall, the findings show that the developed novel air-jet spun PCL-DNS nanocomposite scaffolds can be used as cell supportive scaffolds for various tissue engineering applications.

Air-jet spinning corn zein protein nanofibers for drug delivery: Effect of biomaterial structure and shape on release properties.

Nanofiber materials are commonly used as delivery vehicles for dermatological drugs due to their high surface-area-to-volume ratio, porosity, flexibility, and reproducibility. In this study air-jet spinning was used as a novel and economic method to fabricate corn zein nanofiber meshes with model drugs of varying solubility, molecular weight and charge. The release profiles of these drugs were compared to their release from corn zein films to elucidate the effect of geometry and structure on drug delivery kinetics. In film samples, over 50% of drug was released after only 2 h. However, fiber samples exhibited more sustained release, releasing less than 50% after one day. FTIR, SEM, and DSC were performed on nanofibers and films before and after release of the drugs. Structural analysis revealed that the incorporation of model drugs into the fibers would transform the zein proteins from a random coil network to a more alpha helical structure. Upon release, the protein fiber reverted to its original random coil network. In addition, thermal analysis indicated that fibers can protect the drug molecules in high temperature above 160 °C, while drugs within films will degrade below 130 °C. These findings can likely be attributed to the mechanical infiltration of the drug molecules into the ordered structure of the zein fibers during their solution fabrication. The slow release from fiber samples can be attributed to this biophysical interaction, illustrating that release is dictated by more than diffusion in protein-based carriers. The controlled release of a wide variety of drugs from the air-jet spun corn zein nanofiber meshes demonstrates their success as drug delivery vehicles that can potentially be incorporated into different biological materials in the future.

Air-Jet Spun Corn Zein Nanofibers and Thin Films with Topical Drug for Medical Applications.

Diabetic patients are especially susceptible to chronic wounds of the skin, which can lead to serious complications. Sodium citrate is one potential therapeutic molecule for the topical treatment of diabetic ulcers, but its viability requires the assistance of a biomaterial matrix. In this study, nanofibers and thin films fabricated from natural corn zein protein are explored as a drug delivery vehicle for the topical drug delivery of sodium citrate. Corn zein is cheap and abundant in nature, and easily extracted with high purity, while nanofibers are frequently cited as ideal drug carriers due to their high surface area and high porosity. To further reduce costs, the 1-D nanofibers in this study were fabricated through an air jet-spinning method rather than the conventional electrospinning method. Thin films were also created as a comparative 2-D material. Corn zein composite nanofibers and thin films with different concentration of sodium citrate (1-30%) were analyzed through FTIR, DSC, TGA, and SEM. Results reveal that nanofibers are a much more effective vehicle than films, with the ability to interact with sodium citrate. Thermal analysis results show a stable material with low degradation, while FTIR reveals strong control over the protein secondary structures and hold of citrate. These tunable properties and morphologies allow the fibers to provide a sustained release of citrate and then revert to their structure prior to citrate loading. A statistical analysis via t-test confirmed a significant difference between fiber and film drug release. A biocompatibility study also confirms that cells are much more tolerant of the porous nanofiber structure than the nonporous protein films, and lower percentages of sodium citrate (1-5%) were outperformed to higher percentages (15-30%). This study demonstrated that protein-based nanofiber materials have high potential as vehicles for the delivery of topical diabetic drugs.

In vitro and in vivo biological characterization of poly(lactic acid) fiber scaffolds synthesized by air jet spinning.

Poly(lactic acid) (PLA) is one of the most promising renewable and biodegradable polymers for mimic extracellular matrix for tissue engineering applications. In this work, PLA spun membrane scaffold were successfully prepared by air jet spinning technology. Morphology, mechanical properties, in vitro biocompatibility, and in vitro and in vivo degradation of PLA fibrous scaffold were characterized by X-ray diffraction, Fourier Transform Infrared, and scanning electron microscope (SEM). Morphological results assessed by SEM analyses indicated that PLA scaffolds possessed an average fiber diameter of approximately 0.558 ± 0.141 µm for 7% w/v of PLA and approximately 0.647 ± 0.137 µm for 10% w/v. Interestingly, our results showed that the nanofiber size of PLA scaffold allow structural stability after 100 days of in vitro degradation in Ringer solution where the average fiber diameter were of approximately 0.633 ± 0.147 µm for 7% w/v and approximately 0.645 ± 0.140 µm for 10% w/v of PLA. Mechanical properties of PLA fibers scaffold after in vitro degradation showed decrease in terms of flexibility elongation, and less energy was needed to achieve maximal elastic deformation. The fiber size exerts an influence on the biological response of human Bone Marrow Mesenchymal Stromal Cells as confirmed by MTT assay after 9 days of cell culture and the in vivo degradation assay of 7% w/v and 10% w/v of PLA scaffold, did not demonstrate evidence of toxicity with a mild inflammatory respond. In conclusion, airbrushing technology promises to be a viable and attractive alternative technique for producing a biocompatible PLA nanofiber scaffold that could be considered for tissue engineering regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2435-2446, 2018.

Adhesión y proliferación de las células troncales mesenquimales de médula ósea en andamios fibrilares de poli (ácido L-láctico) (PLA) / Adhesion and proliferation of bone marrow mesenchymal stem cells onto poli-L lactic acid (PLA) fiber scaffolds

Resumen: Los andamios fibrilares han recibido un enorme interés como futuros biomateriales con potencial aplicación en el campo de la biomedicina regenerativa. En este sentido, hemos optimizado los parámetros para la síntesis de diferentes concentraciones (6, 7, y 10 %) de andamios de ácido poli-láctico (PLA) por la técnica de hilado por propulsión de gas (AJS). Dichos andamios fueron caracterizados por Microscopía Electrónica de Barrido (SEM) y por espectrometría Infrarroja con Transformada de Fourier (FTIR). Nuestros resultados mostraron que los andamios son fibrilares con diámetros en escalas nanométricas. Asimismo; se estudió la biocompatibilidad celular in vitro al realizar ensayos de adhesión, proliferación y de interacción célula-material al cultivar células troncales mesenquimales derivadas de médula ósea. Nuestros datos indican que las membranas fibrilares de PLA aumentan la respuesta celular, no son citotóxicas al compararse con las películas delgadas de PLA. Por lo tanto; el método de síntesis propuesto tiene potencial para la fabricación de membranas hiladas con una facilidad de procesamiento y podría ser un prometedor biomaterial económico con futuras aplicaciones en la regeneración de tejidos.

Abstract: Fiber scaffolds have received increasing interest as promising biomaterials for potential application in the field of tissue regeneration. In this sense, we optimized the parameters for the synthesis of different concentrations (6, 7, and 10 %) of poly-lactic acid (PLA) scaffolds by air jet spinning technology (AJS). The PLA scaffolds were characterized by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis. Our results by SEM micrographs showed that scaffolds have a fibrilar morphology with nanoscale diameter of fibers. Biocompatibility assay was observed through an in vitro experiment based on cell attachment, MTT and cell-material interaction assay when culturing bone marrow-derived mesenchymal stem cells onto the PLA spun membrane scaffolds. Our data indicate that fiber membrane of PLA scaffold increase the cellular response, are not cytotoxic when compared to thin films of PLA. Thus; the proposed synthesis method has potential for easy processing of spun fibrilar scaffolds with good biocompatibility and could be a promising economical biomaterial with future potential applications in tissue regeneration.

Biocorrosion behavior of biodegradable nanocomposite fibers coated layer-by-layer on AM50 magnesium implant.

This article demonstrates the use of hybrid nanofibers to improve the biodegradation rate and biocompatibility of AM50 magnesium alloy. Biodegradable hybrid membrane fiber layers containing nano-hydroxyapatite (nHA) particles and poly(lactide)(PLA) nanofibers were coated layer-by-layer (LbL) on AM50 coupons using a facile single-step air jet spinning (AJS) approach. The corrosion performance of coated and uncoated coupon samples was investigated by means of electrochemical measurements. The results showed that the AJS 3D membrane fiber layers, particularly the hybrid membrane layers containing a small amount of nHA (3 wt.%), induce a higher biocorrosion resistance and effectively decrease the initial degradation rate compared with the neat AM50 coupon samples. The adhesion strength improved highly due to the presence of nHA particles in the AJS layer. Furthermore, the long biodegradation rates of AM50 alloy in Hank's balanced salt solution (HBSS) were significantly controlled by the AJS-coatings. The results showed a higher cytocompatibility for AJS-coatings compared to that for neat Mg alloys. The nanostructured nHA embedded hybrid PLA nanofiber coating can therefore be a suitable coating material for Mg alloy as a potential material for biodegradable metallic orthopedic implants.

A novel simple one-step air jet spinning approach for deposition of poly(vinyl acetate)/hydroxyapatite composite nanofibers on Ti implants.

A biocompatible coating consists of a poly(vinyl acetate)/hydroxyapatite (PVAc/HA) composite nanofiber mat was applied to NaOH-treated titanium metal by means of a novel, facile and efficient air jet spinning (AJS) approach. Results showed that HA nanoparticles (NPs) strongly embedded onto the AJS single fiber surface resulting in a strong chemical interfacial bonding between the two phases due to the difference in kinetic energies. It was proven that AJS membrane coatings can provide significant improvement in the corrosion resistance of titanium substrate. Interestingly, the biocompatibility using MC3T3-E1 osteoblast to the PVAc/HA fiber composite layer coated on Ti was significantly higher than pure titanium-substrates.