Gelatin Nanofibers Research Articles

Gelatin nanofibers: Analysis of triple helix dissociation temperature and cold-water-solubility

Gelatin nanofibrous structures, characterized by high specific surface area and high porosity, have been widely researched for biomedical and food applications. The present paper researches the potential of electrospinning to produce a nanofibrous cold-gelling (or instant) gelatin product. Our results show that gelatin nanofibers are cold-water-soluble due to their high surface-to-volume ratio, facilitating easy water penetration and dissolution, and this for several gelatin types. Additionally, fast gelation after dissolution in cold water indicates that the electrospinning process does not significantly reduce the gelatin molecular weight, nor compromise triple helix formation. These conclusions were supported by thorough investigation of the internal gelatin structure, using a new approach based on modulated temperature scanning calorimetry. Oscillation rheology revealed that the nanofiber-based gels have moduli comparable to powder-based gels. Gelatin nanofibers can thus be used as instant gelatin product, without the drawbacks of traditional amorphous instant gelatins such as sensitivity to moisture, low wettability and low modulus of the cold gel. Using the approach reported here, every electrospinnable, but non-cold-water-soluble gelatin can be transformed into a cold-water-soluble variant, regardless of the type or modification. Electrospinning can thus offer enormous flexibility in materials selection, enabling the production of cold gels loaded with temperature-sensitive components, UV-cross-linkable cold gels, etc.

Preparation and characterization of electrospun in-situ cross-linked gelatin-graphite oxide nanofibers

Electrospun gelatin(Gel) nanofibers scaffold has such defects as poor mechanical property and quick degradation due to high solubility. In this study, the in situ cross-linked electrospinning technique was used for the production of gelatin nanofibers. Deionized water was chosen as the spinning solvent and graphite oxide (GO) was chosen as the enhancer. The morphological structure, porosity, thermal property, moisture absorption, and moisture retention performance, hydrolysis resistance, mechanical property, and biocompatibility of the produced nanofibers were investigated. Compared with in situ cross-linked gelatin nanofibers scaffold, in situ cross-linked Gel-GO nanofibers scaffold has the following features: (1) the hydrophilicity, moisture absorption, and moisture retention performance slightly reduce, while the hydrolysis resistance is improved; (2) the breaking strength, breaking elongation, and Young’s modulus are significantly improved; (3) the porosity slightly reduces while the biocompatibility considerably increases. The in situ cross-linked Gel-GO nanofibers scaffold is likely to be applied in such fields as drug delivery and scaffold for skin tissue engineering.

In vitro evaluation of electrospun gelatin–glutaraldehyde nanofibers

The gelatin–glutaraldehyde (gelatin–GA) nanofibers were electrospun in order to overcome the defects of ex-situ crosslinking process such as complex process, destruction of fiber morphology and decrease of porosity. The morphological structure, porosity, thermal property, moisture absorption and moisture retention performance, hydrolytic resistance, mechanical property and biocompatibility of nanofiber scaffolds were tested and characterized. The gelatin–GA nanofiber has nice uniform diameter and more than 80% porosity. The hydrolytic resistance and mechanical property of the gelatin–GA nanofiber scaffolds are greatly improved compared with that of gelatin nanofibers. The contact angle, moisture absorption, hydrolysis resistance, thermal resistance and mechanical property of gelatin–GA nanofiber scaffolds could be adjustable by varying the gelatin solution concentration and GA content. The gelatin–GA nanofibers had excellent properties, which are expected to be an ideal scaffold for biomedical and tissue engineering applications.

Green electrospinning of gelatin and pullulan nanofibers to mimic the extracellular matrix

Event Abstract Back to Event Green electrospinning of gelatin and pullulan nanofibers to mimic the extracellular matrix Yongfang Qian1, 2 and Martin King2 1 Dalian Polytechnic University, School of Textile and Material Engineering, China 2 North Carolina State University, College of Textiles, United States Introduction: Electrospinning is a process that uses the electrical to stretch a viscous solution or melt by the applied potential to form nanofibers. However, most current electrospinning process involves the usage of organic solvents and most of the solvents used are toxic and corrosive, which will bring serious environment problem. Therefore, “Green Electrospinning” was proposed as an approach of fabricating nanofibers by electrospinning from aqueous concentration[1]. The extracellular matrix (ECM) is a complex of structural and functional proteins, glycoproteins, and proteoglycans arranged in a unique, tissue specific three-dimensional ultrastructure[2],[3]. Gelatin is a protein biopolymer derived from partial hydrolysis of native collagens, which are the most abundant structural proteins found in the animal body of skin, tendon, cartilage and bone[4]. Pullulan is an extracellular linear polysaccharide produced by the fungus-like yeast, Aureobasidium pullulans[5]. In the present work, gelatin and pullulan were electrospun into nanofibers by electrospinning to mimic the extracellular matrix. The morphology of electrospun nanofibers was observed by SEM. The fiber diamter distribution was also discussed in this study. Materials and Methods: Materials: Gelatin (Type A, 300 bloom) was purchased from Sigma-Aldrich Chemical Company (St. Louis, Missouri, USA). Pullulan at food grade was purchased from Hayashibara Biochemical Laboratories Inc. (Okayama, Japan). Doubly distilled water was used as a solvent to prepare all solutions. All products were received without further purification. Electrospinning: Gelatin and pullulan were dissolved in doubly distilled water seperately at room temperature under magnetic stirring. The result solution was fed into plastic syringe. During electrospinning, a positive high voltage of 24 kV generated by a high voltage power supply (JDF-1, China) was applied at the tip of a syringe needle. The electrospun nanofibers were collected on a piece of aluminum foil covered on an electrically grounded metal plate, which was placed at a distance of 12 cm below the tip of the syringe needle. The mass flow rate was maintained at 0.6 ml/h by extremely accurate syringe pump (789100C, Cole-Parmer, USA). The electrospinning was conducted under the ambient conditions. The behavior of the pullulan solution during electrospinning was observed visually. The morphology of electrospun nanofibers were observed by SEM (JSM 6460, JEOL Ltd, Japan). Results and Discussion: The gelatin and pullulan complex were successfully electrospun into nanofibers for aqueous solution, as shown in figure 1. The concentration or the corresponding viscosity was one of the most effective variables to control the fiber morphology. Meanwhile the weight ratio between gelatin and pullulan will also affect the size and morphology of diameter. As shown in figure 2, the average diameter was 152nm, and fiber diameter ranged from 100 to 200nm. Moreover, the interaction between gelatin and pullulan will further be investigated. Figure1. SEM image of electrospun gelatin and pullulan nanofibers Figure2. Size distribution of electrospun gelatin and pullulan nanofibers Conclusion: Gelatin and pullulan complex as a novel mimic system has been successfully electrospun into nanofibers from aqueous solution, which will avoid the harm of organic solvents. The new complex has potential application in tissue engineering scaffolds. China Scholarship Concil

Induction and differentiation of human induced pluripotent stem cells into functional cardiomyocytes on a compartmented monolayer of gelatin nanofibers.

Extensive efforts have been devoted to develop new substrates for culture and differentiation of human induced pluripotent stem cells (hiPSCs) toward cardiac cell-based assays. A more exciting prospect is the construction of cardiac tissue for robust drug screening and cardiac tissue repairing. Here, we developed a patch method by electrospinning and crosslinking of monolayer gelatin nanofibers on a honeycomb frame made of poly(ethylene glycol) diacrylate (PEGDA). The monolayer of the nanofibrous structure can support cells with minimal exogenous contact and a maximal efficiency of cell-medium exchange whereas a single hiPSC colony can be uniformly formed in each of the honeycomb compartments. By modulating the treatment time of the ROCK inhibitor Y-27632, the shape of the hiPSC colony could be controlled from a flat layer to a hemisphere. Afterwards, the induction and differentiation of hiPSCs were achieved on the same patch, leading to a uniform cardiac layer with homogeneous contraction. This cardiac layer could then be used for extracellular recording with a commercial multi-electrode array, showing representative field potential waveforms of matured cardiac tissues with appropriate drug responses.

Internal crosslinking evaluation of gelatin electrospinning fibers with 1,4 � butanediol Diglycidyl ether (Bddge) for skin regeneration

Event Abstract Back to Event Internal crosslinking evaluation of gelatin electrospinning fibers with 1,4 – butanediol Diglycidyl ether (Bddge) for skin regeneration Juliana Dias1, 2, 3, 4, Pedro L. Granja2, 3, 4, 5 and Paulo J. Bártolo6 1 INEB, Biocarrier Group, Portugal 2 IPL, CDRsp, Portugal 3 University of Porto, ICBAS, Portugal 4 University of Porto, I3S, Portugal 5 FEUP - Faculdade de Engenharia da Universidade do Porto, Engenharia Metalúrgica e Materiais, Portugal 6 University of Manchester, fSchool of Mechanical, Aerospace and Civil Engineering & Manchester Institute of Biotechnology, United Kingdom Skin is the largest vital organ in the body, having as the main function the protection of the human being against the external environment[1][2][3][4][5] . Although skin has a self-regeneration ability, this capacity is strongly reduced in the case of full-thickness lesions making necessary the use of grafts or dressings [2]. The usual procedure when the skin damage occurs consists in the application of a wound dressing due their efficiency, low cost and availability [6][7]. Wound dressing made from electrospun nanofibers present advantageous properties compared to the conventional dressings such as potential to promote hemostasis phase, wound exudates absorption, semi-permeability, easy conformability to the wound, functional ability and no scar induction[8] .Gelatin nanofiber mats can mimic ECM structure of the human tissues and organs and is widely used in the tissue engineering field because of its excellent bio-affinity, biological origin, biocompatibility, non-immunogenicity, biodegradability and commercial availability[9][10]. However, gelatin is a water-soluble protein derived from partial hydrolysis of collagen and a crosslinking is needed to improve its mechanical properties, increase stability, and make gelatin meshes insoluble in water [10]. There are several crosslinking methods by adding enzyme such as transglutaminase [11][12] or chemical agents such as fructose [13], dextran dialdehyde [14], diepoxy [15], formaldehyde [16], glutaraldehyde [13][16][17], genipin [15][18][19], diisocyanates [20], or carbodiimides[21]. The traditional aldehyde-based crosslinking strategy has provided a powerful tool to tailor the physical properties of gelatin films [22][23][24] although the assumed toxicity of such chemicals makes uncertain their use [22]. Epoxy compounds are preferred as a stabilizing agent of collagen-based materials for biomedical applications due to their lower toxicity compared with commonly used dialdehydes [25][26][27]. Based on this, the search for alternative crosslinkers that present low toxicity and good stability is the objective of this work. Amongst water-soluble polyepoxides, 1,4-butanediol diglycidyl ether (BDDGE) is commercially available as a cross-linking agent in dermal filler formulations [26]. Although un-reacted BDDGE should be considered from slightly to moderately toxic [27], residual BDDGE might undergo hydrolysis yielding a diol-ether (3,3′(butane-1,4-diylbis(oxy)) bis propane-1,2-diol) which has been proved to be non-toxic limiting safety risks[26]. The present study evaluates the ability of BDDGE to crosslink gelatin nanofibers from porcine skin. The extent of crosslinking was evaluated according different Bddge concentrations at different time-points. Mechanical, thermal, physical and biological properties were investigated as well. According the results we can concluded that BDDGE showed a huge potential as gelatin crosslinker due several reasons, such as, its incorporation on electrospun fibers reducing its diameter in 37.9%, the temperature influence directly the crosslinking process accelerate the chemical reaction, range the BDDGE concentration and incubation time is possible control the extension of crosslinking reducing the un-reacted groups and consequently reducing or eliminating the toxicity. According the results achieved BDDGE can be considered a good alternative to crosslink the gelatin for tissue engineering applications. This work is supported by a research grant (SFRH/BD/91104/2012) awarded to Juliana Dias by Portuguese FCT.

Fast Coprecipitation of Calcium Phosphate Nanoparticles inside Gelatin Nanofibers by Tricoaxial Electrospinning

We present an effective method for fabricating electrospun gelatin nanofibers containing well-dispersed inorganic nanoparticles. The new method encompasses the use of a special triaxial needle where mixing calcium and phosphate aqueous solutions in an intermediate needle yield calcium phosphate (CaP) nanoparticles that immediately after precipitation are dragged by the outer polymeric solution and incorporated directly in the electrospinning jet, before nanofiber formation. Gelatin electrospun mats containing different amounts of CaP nanoparticles were prepared and characterized by SEM, TEM, TGA, and stress-strain measurements. The results demonstrate that CaP particles having diameter of few tens of nanometers were successfully introduced in the gelatin nanofibers during the electrospinning process and that they were well dispersed throughout the fiber length. In addition, the use of the special triaxial needle enabled modulating the CaP amount in the nanofibers.

Fracture behaviour of nanofibrous hydrogel composites

Event Abstract Back to Event Fracture behaviour of nanofibrous hydrogel composites Annabel Butcher1, 2 and Michelle L. Oyen1, 2 1 University of Cambridge, Department of Engineering, United Kingdom 2 University of Cambridge, The Nanoscience Centre, United Kingdom Introduction: Hydrogels are a popular choice for cartilage tissue engineering (TE) scaffolds due to their hydrophilicity[1]. Closely mimicking the highly hydrated extracellular matrix of biological tissues increases the scaffold’s biocompatibility. However, use of hydrogels within TE is limited by poor mechanical properties, preventing their use as a long term solution for cartilage damage[2]. The properties of natural cartilage could be reproduced by successfully imitating the nanostructure of cartilage, creating a scaffold that models the extracellular matrix as a fibre reinforced hydrogel. The fibres mimic the nanoscale collagen fibres within cartilage, and the hydrogel mimics the proteoglycan ground substance and allows for the large water content of natural cartilage. This study utilises electrospinning to create a mesh of gelatin nanofibres that are infiltrated with a hydrogel to create a fibre reinforced composite. Materials and Methods: A 12 wt % gelatin solution was prepared, with citric acid as a crosslinker and sodium hypophoshite as a catalyst in a 90 v/v % aqueous acetic acid solution. The solution was prepared at room temperature and then electrospun horizontally for four hours. The nanofibrous meshes were then removed from the collector and crosslinked at 150°C for four hours, creating gelatin fibres that are stable in water. These fibres were then infiltrated with a homogeneous alginate hydrogel or a double network hydrogel to create fibre reinforced composites. Unidirectional tensile tests and mode III toughness tests were conducted on an Instron (5544 universal testing machine) to compare the mechanical properties of the fibrous meshes, the crosslinked hydrogels, and the composites. Atomic force microscopy (AFM) was used to study single fibres within the meshes, and dual beam focused ion beam (FIB) scanning electron microscopy (SEM) was used to visualise the structures in 3D. Results and Discussion: Figure 1 shows the microstructure of the four materials tested. It can be seen the fibres have swollen when placed in water, and that the hydrogel has infiltrated the fibres to create a composite. The tensile tests demonstrated the addition of randomly aligned fibres to a hydrogel can more than double the tensile strength and the elastic modulus. Toughness was calculated from mode III fracture tests as the analysis is independent of geometry. The fibres improved the toughness of the hydrogels to greater than either of the independent components of the composite. Alginate on its own has a toughness of just 0.04 kJ/m2, which is increased to 0.17 kJ/m2 when reinforced with randomly aligned nanofibres as shown in Figure 2. There are established models that predict the effects of fibre reinforcement within a composite. However these are difficult to apply to electrospun fibre reinforced hydrogels due to the uncertainty in parameters caused by the small length scale and variability in the method of manufacture. The mechanical properties of electrospun fibres can be determined by using an AFM for three-point bending tests, or by calculation modelling the fibrous mesh as an open celled foam. The volume fraction of the fibres within the composites can be estimated using the porosity of the fibrous mesh or by using FIB SEM images to create a 3D model. These values are used to calculate the upper and lower bounds of the composite properties and compared with the experimental results, as shown in figure 3. Conclusions: Fibre reinforced hydrogels are made using electrospun gelatin nanofibres and composite theory is used to demonstrate the potential of these materials. The fibre reinforcement improves the tensile properties and the toughness of the hydrogels, towards that of natural healthy cartilage. This work was funded by the Engineering and Physical Sciences Research Council (1354760)

Effective motor neuron differentiation of hiPSCs on a patch made of crosslinked monolayer gelatin nanofibers.

Human induced pluripotent stem cells (hiPSCs) are differentiated into mature motor neurons by using a culture patch made of crosslinked monolayer gelatin nanofibers. Compared to the conventional culture dish method, the patch method is more effective for culture and differentiation of stem cells, because cells are supported by a net-like structure made of crosslinked monolayer nanofibers instead of a planar substrate. The pores of the net-like structure have sizes smaller than those of cells but large enough to minimize the exogenous cell-material contact and to increase the permeability as well as the efficiency of cell-cell interactions. As expected, the differentiated hiPSCs showed the up-regulation of the expression of neuron specific proteins and the signature of matured motor neurons, allowing plug-and-play with a commercial multi-electrode array for neuron spike recording.

Electrospun gelatin nanofibers loaded with vitamins A and E as antibacterial wound dressing materials

Illustration showing the fabrication process and test contents of electrospun gelatin nanofibers loaded with vitamins A and E as wound dressing materials in this paper.

Electrospun gelatin nanofibers as drug carrier: effect of crosslinking on sustained release

This study aims to develop a natural biopolymer based nanofabric as an oral drug carrier to deliver a model hydrophobic drug (piperine) in a sustained and controlled manner over prolonged time. For that, we electrospun gelatin nanofabric mesh followed by crosslinking using saturated vapor of glutaraldehyde (GTA) for 8 mins to improve the water resistive properties. Later, we investigated the effect of different crosslinking strategies and found that layer-by-layer crosslinking not only provides an improved structural integrity, thermal and chemical stability of drug but also yields a tight control over sustained drug release up to 8 h.

Fabrication and characterization of cefazolin-loaded nanofibrous mats for the recovery of post-surgical wound

The aim of the present study was to evaluate the wound healing performance of cefazolin-loaded gelatin nanofiber mats in post-operative wound. The obtained nanofibers were smooth, non-beaded and having diameter ranging from 620–680 nm. Nanofiber mats that are prepared exhibit high drug entrapment, excellent oxygen permeability and sustained drug release behavior. Further, medicated nanofiber mats showed an accelerated wound healing as compared to plain cefazolin. Macroscopical and histological evaluations demonstrated that cefazolin-loaded gelatin nanofiber showed increased epithelialization rate and collagen deposition. The results indicated that therapeutic strategies offer new prospects in the management of post-operative wound repair.

In-vitro release study of hydrophobic drug using electrospun cross-linked gelatin nanofibers

Delivering hydrophobic drug within hydrophilic polymer matrix as carrier is usually a challenge. Here we report the synthesis of gelatin nanofibers by electrospinning, followed by testing them as a potential carrier for oral drug delivery system for a model hydrophobic drug, piperine. Electrospun gelatin nanofibers were crosslinked by exposing to saturated glutaraldehyde (GTA) vapor, to improve their water resistive properties. An exposure of only 6min was not only adequate to control the early degradation with intact fiber morphology, but also significantly marginalized any adverse effects associated with the use of GTA. Scanning electron microscopy imaging, Fourier transform infrared spectroscopy and thermogravimetric analysis were done to study nanofiber morphology, stability of drug and effect of crosslinking. The pH of release medium was also varied as per the gastrointestinal tract for in-vitro drug release study. Results illustrate good compatibility of hydrophobic drug in gelatin nanofibers with promising controlled drug release patterns by varying crosslinking time and pH of release medium.

New Solvent System for the Fabrication of Polyvinyl Alcohol – Gelatin Nanofibers via Electrospinning

Polyvinyl Alcohol (PVA) is a biocompatible polymer with high mechanical strength used in the biomedical industry. While its features have biological properties, it lacks cell recognition sites that affect the entirety of cell proliferation and movement. To address this issue, gelatin (GEL) is added to the system to increase biomimetic properties. PVA and GEL nanofibers, produced from electrospinning, could provide new characteristics for tissue engineering applications. At present, aqueous solution of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and many other hazardous organic solutions are used in fabricating both PVA, GEL and PVA-GEL nanofibers, but it poses a great threat on sites that the solvent was unable to evaporate, affecting cell viability and motility. In this study, a new solvent system of deionized water, formic acid and glacial acetic acid was used to replace the current toxic solvent system utilized in electrospinning such polymers. Increasing amounts of formic acid and deionized water decreased further the fiber diameter of the PVA-GEL nanofibers. Further refinement in solution (PVA:GEL ratio) and process parameters (tip-to-collector distance and flow rate) produced much finer nanofibers, leading to a decrease in fiber diameter distribution. It is conclusive that a new alternative solvent system can be used in electrospinning PVA-GEL nanofibers that are non-toxic and exhibits much lower fiber diameter (≈20 nm) than the conventional solvents used before.

Gelatin Nanofiber Matrices Derived from Schiff Base Derivative for Tissue Engineering Applications.

Electrospinning of water-soluble polymers and retaining their mechanical strength and bioactivity remain challenging. Volatile organic solvent soluble polymers and their derivatives are preferred for fabricating electrospun nanofibers. We report the synthesis and characterization of 2-nitrobenzyl-gelatin (N-Gelatin)--a novel gelatin Schiff base derivative--and the resulting electrospun nanofiber matrices. The 2-nitrobenzyl group is a photoactivatable-caged compound and can be cleaved from the gelatin nanofiber matrices following UV exposure. Such hydrophobic modification allowed the fabrication of gelatin and blend nanofibers with poly(caprolactone) (PCL) having significantly improved tensile properties. Neat gelatin and their PCL blend nanofiber matrices showed a modulus of 9.08 ± 1.5 MPa and 27.61 ± 4.3 MPa, respectively while the modified gelatin and their blends showed 15.63 ± 2.8 MPa and 24.47 ± 8.7 MPa, respectively. The characteristic infrared spectroscopy band for gelatin Schiff base derivative at 1560 cm(-1) disappeared following exposure to UV light indicating the regeneration of free NH2 group and gelatin. These nanofiber matrices supported cell attachment and proliferation with a well spread morphology as evidenced through cell proliferation assay and microscopic techniques. Modified gelatin fiber matrices showed a 73% enhanced cell attachment and proliferation rate compared to pure gelatin. This polymer modification methodology may offer a promising way to fabricate electrospun nanofiber matrices using a variety of proteins and peptides without loss of bioactivity and mechanical strength.

Transcytosis-Targeting Peptide: A Conductor of Liposomal Nanoparticles through the Endothelial Cell Barrier.

The ultimate goal in the area of drug-delivery systems is the development of a nanoparticle that can penetrate the endothelial cell monolayer for the targeting of tissue parenchyma. In the present study, we identify a transcytosis-targeting peptide (TTP) that permits polyethyleneglycol (PEG)-modified liposomes (PEG-LPs) to penetrate through monolayers of brain-derived endothelial cells. These endothelial cells were layered on a gelatin nanofiber sheet, a nanofiber meshwork that allows the evaluation of transcellular transport of nanosized particles (ca. 100 nm). Systematic modification of the sequences results in the identification of the consensus sequence of TTP as L(R/K)QZZZL, where Z denotes hydrophilic amino acids (R/K/S and partially D). The TTP-modified liposomes are bound on the heparin sulfate proteoglycan, and are then taken up via lipid raft-mediated endocytosis. Subsequent intracellular imaging of the particles reveals a unique intracellular sorting of TTP-modified PEG liposomes (TTP-PEG-LPs); namely the TTP-LPs are not localized with the lysosomes, whereas this co-localization is dominant in the unmodified PEG liposomes (PEG-LPs). The in vivo endothelial penetration of liposomes in adipose tissue is conferred by the dual modification of the particles with TTP and tissue-targeting ligands. This technology promises innovations in intravenously available delivery system to tissue parenchyma.

Potential of Electrospun Graphene Oxide-Gelatin Composite Nanofibers for Biomedical Applications

Graphene oxide incorporated polymer matrix provides a multifunctional facet due to the reinforcing effect of graphene oxide (GO) with wide range of properties. Nanofibers are fabricated by a versatile technique known as electrospinning. The present study demonstrates the fabrication of gelatin, a protein nanofibers non-covalently functionalized with GO. The effect of GO on gelatin nanofibers in terms of mechanical performance is studied. In order to improve the water resistance of the resulting nanofibers, cross-linking is performed using dextran aldehyde.

Development and characterization of cefazolin loaded zinc oxide nanoparticles composite gelatin nanofiber mats for postoperative surgical wounds.

Systemic antibiotic therapy in post-operative wound care remain controversial leading to escalation in levels of multi-resistant bacteria with unwanted morbidity and mortality. Recently zinc (Zn) because of multiple biophysiological functions, gain considerable interest for wound care. Based on our current understanding, the present study was designed with an intent to produce improve therapeutic approaches for post-operative wound management using composite multi-functional antibiotic carrier. The study involved the fabrication, characterization and pre-clinical evaluation of cefazolin nanofiber mats loaded with zinc oxide (ZnO) and comparing co-formulated mats with individual component, enable a side by side comparison of the benefits of our intervention. Minimum inhibitory concentration (MIC) of the drug, ZnO nanoparticles (ZnONPs) and drug-ZnONP mixture against Staphylococcus aureus was determined using micro dilution assay. The fabricated nanofibers were then evaluated for in-vitro antimicrobial activity and the mechanism of inhibition was predicted by scanning electron microscopy (SEM). Further these nanofiber mats were evaluated in-vivo for wound healing efficacy in Wistar rats. Study revealed that the average diameter of the nanofibers is around 200-900 nm with high entrapment efficiency and display sustained drug release behavior. The combination of ZnO and cefazolin in 1:1 weight ratio showed higher anti-bacterial activity of 1.9 ± 0.2 μg/ml. Transmission electron microscopy of bacterial cells taken from the zone of inhibition revealed the phenomenon of cell lysis in tested combination related to cell wall disruption. Further composite medicated nanofiber mats showed an accelerated wound healing as compared to plain cefazolin and ZnONP loaded mats. Macroscopical and histological evaluations demonstrated that ZnONP hybrid cefazolin nanofiber showed enhanced cell adhesion, epithelial migration, leading to faster and more efficient collagen synthesis. Hence the fabricated composite nanofiber mats have the potential to be used as a postoperative antimicrobial wound dressings.

Effect of cellulose nanofibers concentration on mechanical, optical, and barrier properties of gelatin-based edible films

The effect of gelatin, glycerol, and cellulose nanofiber (CNFs) concentrations on the mechanical properties, water vapor permeability, and color parameters of films was evaluated. The results indicate that the color is only affected by the gelatin concentration. Mechanical tests indicated that with increasing concentration of gelatin and CNFs, there is an increase in tensile strength, whereas an increase in glycerol concentration causes an increase in elongation, making the films more flexible. An increased concentration of gelatin and glycerol makes the film more permeable to water vapor, while an increase in the concentration of CNFs reduces this property. Finally, the addition of CNFs to gelatin-based films improves their mechanical and barrier properties (water vapor) without affecting the appearance (color) of the films.

Increasing mechanical strength of electrospun gelatin nanofibers by the addition of aluminum potassium sulfate

ABSTRACTIncreasing mechanical strength of gelatin‐based materials is required to expand the range of their applications, which is desirable because of biocompatibility, biodegradability, and low cost of gelatin. The effect of aluminum potassium sulfate on preparation and properties of nanofibrous gelatin were investigated. Samples were electrospun from 10M aqueous acetic acid and analyzed by scanning electron microscopy (SEM), Fourier transform infrared microscopy (FTIR), energy‐dispersive x‐ray analysis (EDX), and tensile test. The addition of AlK(SO4)2 considerably increases the elastic modulus of the material up to about 10% salt content. The elastic modulus of electrospun gelatin meshes prepared as described in the present work increased from 20 MPa to 70 MPa and the elastic modulus of the fiber material increased from 150 MPa to 620 MPa as the salt content in the fibers increased from 0% to 9.6%. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42431.