Use of semi-permeable bag materials to facilitate on-site treatment of biological agent-contaminated waste.

Clean up following the wide-area release of a persistent biological agent has the potential to generate significant waste. Waste containing residual levels of biological contaminants may require off-site shipment under the U.S. Department of Transportation's (US DOT) solid waste regulations for Category A infectious agents, which has packaging and size limitations that do not accommodate large quantities. Treating the waste on-site to inactivate the bio-contaminants could alleviate the need for Category A shipping and open the possibility for categorizing the waste as conventional solid waste with similar shipping requirements as municipal garbage. To collect and package waste for on-site treatment, a semi-permeable nonwoven-based fabric was developed. The fabric was designed to contain residual bio-contaminants while providing sufficient permeability for penetration by a gaseous decontamination agent. The nonwoven fabric was tested in two bench-scale experiments. First, decontamination efficacy and gas permeability were evaluated by placing test coupons inoculated with spores of a Bacillus anthracis surrogate inside the nonwoven material. After chlorine dioxide fumigation, the coupons were analyzed for spore viability and results showed a ≥6 Log reduction on all test materials except glass. Second, filters cut from the nonwoven material were tested in parallel with commercially available cellulose acetate filters having a known pore size (0.45 µm) and results demonstrate that the two materials have similar permeability characteristics. Overall, results suggest that the nonwoven material could be used to package waste at the point of generation and then moved to a nearby staging area where it could be fumigated to inactivate bio-contaminants.

Advances in high-throughput, high-capacity nonwoven membranes for chromatography in downstream processing: A review.

Nonwoven membranes are highly engineered fibrous materials that can be manufactured on a large scale from a wide range of different polymers, and their surfaces can be modified using a large variety of different chemistries and ligands. The fiber diameters, surface areas, pore sizes, total porosities, and thicknesses of the nonwoven mats can be carefully controlled, providing many opportunities for creative approaches for the development of novel membranes with unique properties to meet the needs of the future of downstream processing. Fibrous membranes are already finding use in ultrafiltration, microfiltration, depth filtration, and, more recently, in membrane chromatography for product capture and impurity removal. This article summarizes the various methods of manufacturing nonwoven fabrics, and the many methods available for the modification of the fiber surfaces. It also reviews recent studies focused on the use of nonwoven fabric devices in membrane chromatography and provides some perspectives on the challenges that need to be overcome to increase binding capacities, decrease residence times, and reduce pressure drops so that eventually they can replace resin column chromatography in downstream process operations.

Assessing Crimp of Fibres in Random Networks with 3D Imaging.

The analysis of fibrous structures using micro-computer tomography (µCT) is becoming more important as it provides an opportunity to characterise the mechanical properties and performance of materials. This study is the first attempt to provide computations of fibre crimp for various random fibrous networks (RFNs) based on µCT data. A parametric algorithm was developed to compute fibre crimp in fibres in a virtual domain. It was successfully tested for six different X-ray µCT models of nonwoven fabrics. Computations showed that nonwoven fabrics with crimped fibres exhibited higher crimp levels than those with non-crimped fibres, as expected. However, with the increased fabric density of the non-crimped nonwovens, fibres tended to be more crimped. Additionally, the projected fibre crimp was computed for all three major 2D planes, and the obtained results were statistically analysed. Initially, the algorithm was tested for a small-size, nonwoven model containing only four fibres. The fraction of nearly straight fibres was computed for both crimped and non-crimped fabrics. The mean value of the fibre crimp demonstrated that fibre segments between intersections were almost straight. However, it was observed that there were no perfectly straight fibres in the analysed RFNs. This study is applicable to approach employing a finite-element analysis (FEA) and computational fluid dynamics (CFD) to model/analyse RFNs.

Algorithm to determine orientation distribution function from microscopic images of fibrous networks: Validation with X-ray microtomography.

Quantitative analysis of fibre orientation in a random fibrous network (RFN) is important to understand their microstructure, properties and performance. 2D fibre orientation distribution presents an in-plane fibre orientation without any information on fibre orientation in thickness direction. This research introduces a fully parametric algorithm for computing 3D fibre orientation as thickness is important for high-density or thick fibrous networks. The algorithm is tested for 3 major classes of nonwoven fabrics called low- (L), medium- (M) and high-density (H) ones. H fabric density is 6-8 times larger than the L fabric density. M fabric density (traditional intermediate fabric density) is 3-4 times larger than the L fabric density. Voxel models of experimental nonwoven webs were generated by an X-ray micro-CT (µCT) system and evaluated with the algorithm. Statistical results showed that a fraction of fibres orientated along the thickness direction increases as fibre density grows. To validate the accuracy of findings, deterministic voxelated virtual fibrous structures, created using mathematical functions were used. This novel algorithm is able to produce a 3D orientation distribution function (ODF) for any RFN including, models of nonwovens produced with various manufacturing parameters, experimentally verified and validated with X-ray µCT. Also, it can compute 2D ODFs of various types of RFNs to evaluate 2D behaviour of fibrous structures. The obtained results are useful for applications in many fields including finite element analysis, computational fluid dynamics, additive manufacturing, etc.

Multiphase CFD Modeling and Experimental Validation of Polymer and Attenuating Air Jet Interactions in Nonwoven Annular Melt Blowing.

In annular melt blowing, fiber formation is achieved by accelerating a molten polymer via drag forces imparted by high velocity air that attenuates the polymer jet diameter. The interactions at the polymer-air interface, which govern the motion of the jets and impact the resulting fiber characteristics, are important but not well understood yet. This work details the development and validation of a multiphase computational fluid dynamics (CFD) model to investigate these interactions and the effects of three key melt blowing process parameters (polymer viscosity and throughput, and air velocity) on two critical fiber attributes - whipping instability and fiber diameter. Simulation results highlighted that whipping instability was driven by the polymer-air velocity differential, and the fiber diameter was primarily modulated by polymer throughput and air velocity. The CFD model was validated by modulating the polymer and air throughputs and analyzing the fiber diameter experimentally. Empirical results showed good agreement between fabricated and model-estimated fiber diameters, especially at lower air velocities. An additional CFD simulation performed using a melt blowing nozzle geometry and process parameters described in literature also confirmed good correlation between model estimates and literature empirical data.

Modeling the Triboelectric Behaviors of Elastomeric Nonwoven Fabrics.

Theoretical modeling of triboelectric nanogenerators (TENGs) is fundamental to their performance optimization, since it can provide useful guidance on the material selection, structure design, and parameter control of relevant systems. Built on the theoretical model of film-based TENGs, here, an analytical model is introduced for conductor-to-dielectric contact-mode nonwoven-based TENGs, which copes with the unique hierarchical structure of nonwovens and details the correlation between the triboelectric output (maximum transferred charge density) and nonwoven structural parameters (thickness, solidity, and average fiber diameter). A series of styrene-ethylene-butylene-styrene nonwoven samples are fabricated through a melt-blowing process to map nonwoven structural features within certain ranges, while an ion-injection protocol is adopted to quantify the triboelectric output with superior consistency and reproducibility. With a database containing structural features and triboelectric output of 43 nonwoven samples, a good model fitting is achieved via nonlinear regression analysis in Python, which also shows good predictive power and suggests the existing of tribo-output maxima at a specific thickness, solidity, or average fiber diameter when other structural parameters are fixed. The model is also successfully applied to a group of polypropylene meltblown nonwovens, which verifies its universality on meltblown-nonwoven-based TENGs.

Solution-Blown Poly(hydroxybutyrate) and ε-Poly-l-lysine Submicro- and Microfiber-Based Sustainable Nonwovens with Antimicrobial Activity for Single-Use Applications.

Antimicrobial nonwovens for single use applications (e.g., diapers, sanitary napkins, medical gauze, etc.) are of utmost importance as the first line of defense against bacterial infections. However, the utilization of petrochemical nondegradable polymers in such nonwovens creates sustainability-related issues. Here, sustainable poly(hydroxybutyrate) (PHB) and ε-poly-l-lysine (ε-PLL) submicro- and microfiber-based antimicrobial nonwovens produced by a novel industrially scalable process, solution blowing, have been proposed. In such nonwovens, ε-PLL acts as an active material. In particular, it was found that most of ε-PLL is released within the first hour of deployment, as is desirable for the applications of interest. The submicro- and microfiber mat was tested against C. albicans and E. coli, and it was found that ε-PLL-releasing microfibers result in a significant reduction of bacterial colonies. It was also found that ε-PLL-releasing antimicrobial submicro- and microfiber nonwovens are safe for human cells in fibroblast culture. Mechanical characterization of these nonwovens revealed that, even though they are felt as soft and malleable, they possess sufficient strength, which is desirable in the end-user applications.

N-Halamine Polypropylene Nonwoven Fabrics with Rechargeable Antibacterial and Antiviral Functions for Medical Applications.

Embedding medical and hygiene products with regenerable antimicrobial functions would have significant implications for limiting pathogen contaminations and reducing healthcare-associated infections. Herein, we demonstrate a scalable and industrially feasible methodology to fabricate chlorine rechargeable melt-blown polypropylene (PP) nonwoven fabrics, which have been widely used in hygienic and personal protective products, via a combination of a melt reactive extrusion process and melt-blown technique. Methacrylamide (MAM) was employed as a precursor of halamine monomers and covalently grafted onto the PP backbone to form polypropylene-grafted methacrylamide (PP-g-MAM), which could be chlorinated, yielding biocidal acyclic halamines. Subsequently, the resultant PP-g-MAM was manufactured into nonwoven fabrics with varying fiber diameters by adjusting the hot air flowing speed during the melt-blowing process. The chlorinated nonwoven fabrics (PP-g-MAM-Cl) exhibited integrated properties such as a robust mechanical property, good thermal stability, high chlorination capability (>850 ppm), and desirable chlorine rechargeability. More importantly, such chlorinated nonwoven fabrics showed a promising antibacterial and antiviral efficiency, achieving 6 log CFU reduction of bacteria (both Escherichia coliO157: H7 and Listeria innocua) and 7 log PFU reductions of a virus (T7 bacteriophages) within 15 and 5 min of contact, respectively, revealing great potential to serve as a reusable antimicrobial material for medical protection applications.

Photodynamic Coatings on Polymer Microfibers for Pathogen Inactivation: Effects of Application Method and Composition.

A substantial increase in the risk of hospital-acquired infections (HAIs) has greatly impacted the global healthcare industry. Harmful pathogens adhere to a variety of surfaces and infect personnel on contact, thereby promoting transmission to new hosts. This is particularly worrisome in the case of antibiotic-resistant pathogens, which constitute a growing threat to human health worldwide and require new preventative routes of disinfection. In this study, we have incorporated different loading levels of a porphyrin photosensitizer capable of generating reactive singlet oxygen in the presence of O2 and visible light in a water-soluble, photo-cross-linkable polymer coating, which was subsequently deposited on polymer microfibers. Two different application methods are considered, and the morphological and chemical characteristics of these coated fibers are analyzed to detect the presence of the coating and photosensitizer. To discern the efficacy of the fibers against pathogenic bacteria, photodynamic inactivation has been performed on two different bacterial strains, Staphylococcus aureus and antibiotic-resistant Escherichia coli, with population reductions of >99.9999 and 99.6%, respectively, after exposure to visible light for 1 h. In response to the current COVID-19 pandemic, we also confirm that these coated fibers can inactivate a human common cold coronavirus serving as a surrogate for the SARS-CoV-2 virus.

High-Throughput Manufacture of 3D Fiber Scaffolds for Regenerative Medicine.

Engineered scaffolds used to regenerate mammalian tissues should recapitulate the underlying fibrous architecture of native tissue to achieve comparable function. Current fibrous scaffold fabrication processes, such as electrospinning and three-dimensional (3D) printing, possess application-specific advantages, but they are limited either by achievable fiber sizes and pore resolution, processing efficiency, or architectural control in three dimensions. As such, a gap exists in efficiently producing clinically relevant, anatomically sized scaffolds comprising fibers in the 1-100 µm range that are highly organized. This study introduces a new high-throughput, additive fibrous scaffold fabrication process, designated in this study as 3D melt blowing (3DMB). The 3DMB system described in this study is modified from larger nonwovens manufacturing machinery to accommodate the lower volume, high-cost polymers used for tissue engineering and implantable biomedical devices and has a fiber collection component that uses adaptable robotics to create scaffolds with predetermined geometries. The fundamental process principles, system design, and key parameters are described, and two examples of the capabilities to create scaffolds for biomedical engineering applications are demonstrated. Impact statement Three-dimensional melt blowing (3DMB) is a new, high-throughput, additive manufacturing process to produce scaffolds composed of highly organized fibers in the anatomically relevant 1-100 µm range. Unlike conventional melt-blowing systems, the 3DMB process is configured for efficient use with the relatively expensive polymers necessary for biomedical applications, decreasing the required amounts of material for processing while achieving high throughputs compared with 3D printing or electrospinning. The 3DMB is demonstrated to make scaffolds composed of multiple fiber materials and organized into complex shapes, including those typical of human body parts.

Mutual Sliding Motion of Wrapped Filaments for Biomedical and Engineering Applications.

Here we aim at understanding and modeling of macroscopic interactions and sliding motion of curved filaments during muscles' isometric action in which tension is developed without overall contraction. A generic dynamic model of a curved elastic filament undergoing sliding, twisting, and unraveling around a cylindrical filament affected by the interfilament friction force is developed in full detail. In particular, the dynamic equations describing the general sliding motion of a curved filament wrapped around a cylindrical filament and pulled by a constant force applied to a free end are derived and solved numerically; the other end of the curved filament is considered to be fixed at the cylindrical one. The model predicts propagation of an elastic wave over the wrapped filament determined by the filament stiffness and the interfilament friction. The wrapped filament deformation and its ultimate arrest are predicted, and the final configurations of such filaments are revealed. Accordingly, the wrapped filament strain is predicted as a function of time for different values of the friction coefficient. The potential applications and possible biomechanical links of the proposed generic model are also discussed.

Industrial-scale fabrication of an osteogenic and antibacterial PLA/silver-loaded calcium phosphate composite with significantly reduced cytotoxicity.

In this study, we report an industrial-scale fabrication method of a multifunctional polymer composite as a scaffold material for bone tissue engineering. This study successfully demonstrated the potential of applying industrial polymer processing technologies to produce specially functionalized tissue engineering scaffolds. With the inclusion of a newly synthesized multifunctional additive, silver-doped-calcium phosphate (silver-CaP), the composite material exhibited excellent osteogenic inducibility of human adipose-derived stem cells (hASC) and satisfactory antibacterial efficacy against Escherichia coli and Staphylococcus aureus. Also, relative to previously reported methods of direct loading silver particles into polymeric materials, our composite exhibited significantly reduced silver associated cytotoxicity. The enhanced biocompatibility could be a significant advantage for materials to be used for regenerative medicine applications where clinical safety is a major consideration. The impact of different silver loading methodologies on hASC' osteogenic differentiation was also studied. Overall, the results of this study indicate a promising alternative approach to produce multifunctional scaffolds at industrial-scale with higher throughput, lower cost, and enhanced reproducibility. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 900-910, 2019.

Electrospun Mat of Poly(vinyl alcohol)/Graphene Oxide for Superior Electrolyte Performance.

Here, we describe an electrospun mat of poly(vinyl alcohol) (PVA) and graphene oxide (GO) as a novel solid-state electrolyte matrix, which offers better performance retention upon drying after infiltrated with aqueous electrolyte. The PVA-GO mat overcomes the major issue of conventional PVA-based electrolytes, which is the ionic conductivity decay upon drying. After exposure to 45 ± 5% relative humidity at 25 °C for 1 month, its conductivity decay is limited to 38.4%, whereas that of pure PVA mat is as high as 84.0%. This mainly attributes to the hygroscopic nature of GO and the unique nanofiber structure within the mat. Monolithic supercapacitors have been derived directly on the mat via a well-developed laser scribing process. The as-prepared supercapacitor offers an areal capacitance of 9.9 mF cm-2 at 40 mV s-1 even after 1 month of aging under ambient conditions, with a high device-based volumetric energy density of 0.13 mWh cm-3 and a power density of 2.48 W cm-3, demonstrating great promises as a more stable power supply for wearable electronics.

* Meltblown Polymer Fabrics as Candidate Scaffolds for Rotator Cuff Tendon Tissue Engineering.

Various biomaterial technologies are promising for tissue engineering, including electrospinning, but commercial scale-up of throughput is difficult. The goal of the study was to evaluate meltblown fabrics as candidate scaffolds for rotator cuff tendon tissue engineering. Meltblown poly(lactic acid) fabrics were produced with several polymer crystallinities and airflow velocities [500(low), 900(medium) or 1400(high) m3air/h/m fabric]. Fiber diameter, alignment, and baseline bidirectional tensile mechanical properties were evaluated. Attachment and spreading of human adipose-derived stem cells (hASCs) were evaluated over 3 days immediately following seeding. After initial screening, the fabric with the greatest Young's modulus and yield stress was selected for 28-day in vitro culture and for evaluation of tendon-like extracellular matrix production and development of mechanical properties. As expected, airflow velocity of the polymer during meltblowing demonstrated an inverse relationship with fiber diameter. All fabrics exhibited fiber alignment parallel to the direction of collector rotation. All fabrics demonstrated mechanical anisotropy at baseline. Cells attached, proliferated, and spread on all fabrics over the initial three-day culture period. Consistent with the observed loss of integrity of the unseeded biomaterial, hASC-seeded scaffolds demonstrated a significant decrease in Young's modulus over 28 days of culture. However, dsDNA, sulfated glycosaminoglycan, and collagen content increased significantly over 28 days. Histology and polarized light microscopy demonstrated collagen deposition and alignment throughout the thickness of the scaffolds. While fiber diameters approximated an order of magnitude greater than those previously reported for electrospun scaffolds intended for tendon tissue engineering, they were still within the range of collagen fiber diameters found in healthy tendon. The extent of matrix production and alignment was similar to that previously observed for multilayered electrospun scaffolds. While the Young's modulus of scaffolds after 28 days of culture was lower than native rotator cuff tendon, it approximated that reported previously following culture of electrospun scaffolds and was on the same order of magnitude as of current Food and Drug Administration-approved patches for rotator cuff augmentation. Together, these data suggest that with minor polymer and parameter modifications, meltblown scaffolds could provide an economical, high-throughput production alternative method to electrospinning for use in rotator cuff tendon tissue engineering.

Creation and Evaluation of New Porcine Model for Investigation of Treatments of Surgical Site Infection.

Surgical site infection (SSI) is the most common cause of surgical failure, increasing the risks of postoperative mortality and morbidity. Recently, it has been reported that the use of antimicrobial dressings at the incision site help with prevention of SSI. Despite the increased body of research on the development of different types of antimicrobial dressings for this application, to our knowledge, nobody has reported a reliable large animal model to evaluate the efficacy of developed materials in a preclinical SSI model. In this study, we developed a porcine full-thickness incision model to investigate SSI caused by methicillin-resistant Staphylococcus aureus (MRSA), the leading cause of SSI in the United States. Using this model, we then evaluated the efficacy of our newly developed silver releasing nanofibrous dressings for preventing and inhibiting MRSA infection. Our results confirmed the ease and practicality of a new porcine model as an in vivo platform for evaluation of biomaterials for SSI. Using this model, we found that our silver releasing scaffolds significantly reduced bacterial growth in wounds inoculated with MRSA relative to nontreated controls and to wounds treated with the gold standard, silver sulfadiazine, without causing inflammation at the wound site. Findings from this study confirm the potential of our silver-releasing nanofibrous scaffolds for treatment/prevention of SSI, and introduce a new porcine model for in vivo evaluation of additional SSI treatment approaches.

Highly Conductive Polypropylene-Graphene Nonwoven Composite via Interface Engineering.

Here we report a highly conductive polypropylene-graphene nonwoven composite via direct coating of melt blown polypropylene (PP) nonwoven fabrics with graphene oxide (GO) dispersions in N,N-dimethylformamide (DMF), followed by the chemical reduction of GO with hydroiodic acid (HI). GO as an amphiphilic macromolecule can be dispersed in DMF homogeneously at a concentration of 5 mg/mL, which has much lower surface tension (37.5 mN/m) than that of GO in water (72.9 mN/m, at 5 mg/mL). The hydrophobic PP nonwoven has a surface energy of 30.1 mN/m, close to the surface tension of GO in DMF. Therefore, the PP nonwoven can be easily wetted by the GO/DMF dispersion without any pretreatment. Soaking PP nonwoven in a GO/DMF dispersion leads to uniform coatings of GO on PP-fiber surfaces. After chemical reduction of GO to graphene, the resulting PP/graphene nonwoven composite offers an electrical conductivity of 35.6 S m-1 at graphene loading of 5.2 wt %, the highest among the existing conductive PP systems reported, indicating that surface tension of coating baths has significant impact on the coating uniformity and affinity. The conductivity of our PP/graphene nonwoven is also stable against stirring washing test. In addition, here we demonstrate a monolithic supercapacitor derived from the PP-GO nonwoven composite by using a direct laser-patterning process. The resulted sandwich supercapacitor shows a high areal capacitance of 4.18 mF/cm2 in PVA-H2SO4 gel electrolyte. The resulting highly conductive or capacitive PP/graphene nonwoven carries great promise to be used as electronic textiles.

High-Throughput Fabrication Method for Producing a Silver-Nanoparticles-Doped Nanoclay Polymer Composite with Novel Synergistic Antibacterial Effects at the Material Interface.

In this study, we report a high-throughput fabrication method at industrial pilot scale to produce a silver-nanoparticles-doped nanoclay-polylactic acid composite with a novel synergistic antibacterial effect. The obtained nanocomposite has a significantly lower affinity for bacterial adhesion, allowing the loading amount of silver nanoparticles to be tremendously reduced while maintaining satisfactory antibacterial efficacy at the material interface. This is a great advantage for many antibacterial applications in which cost is a consideration. Furthermore, unlike previously reported methods that require additional chemical reduction processes to produce the silver-nanoparticles-doped nanoclay, an in situ preparation method was developed in which silver nanoparticles were created simultaneously during the composite fabrication process by thermal reduction. This is the first report to show that altered material surface submicron structures created with the loading of nanoclay enables the creation of a nanocomposite with significantly lower affinity for bacterial adhesion. This study provides a promising scalable approach to produce antibacterial polymeric products with minimal changes to industry standard equipment, fabrication processes, or raw material input cost.

Nylon-Graphene Composite Nonwovens as Monolithic Conductive or Capacitive Fabrics.

Here we describe a nylon-graphene nonwoven (NGN) composite, prepared via melt-blowing of nylon-6 into nonwoven fabrics and infiltrate those with graphene oxide (GO) in aqueous dispersions, which were further chemically reduced into graphene to offer electrical conductivity. The correlation between the conductivity and the graphene loading is described by the percolation scaling law σ = (p - pc)t, with an exponent t of 1.2 and a critical concentration pc of 0.005 wt %, the lowest among all the nylon composites reported. Monolithic supercapacitors have been further developed on the nylon-GO nonwoven composites (NGO), via a programed CO2-laser patterning process. The nylon nonwoven works as an efficient matrix, providing high capacity to GO and ensuring enough electrode materials generated via the subsequent laser patterning processes. Our best monolithic supercapacitors exhibited an areal capacitance of 10.37 mF cm-2 in PVA-H2SO4 electrolyte, much higher than the 1-3 mF cm-2 reported for typical microsupercapacitors. Moreover, our supercapacitors were able to retain a capacitance density of 5.07 mF cm-2 at an ultrahigh scan rate (1 V s-1), probably due to the facilitated ion migration within the highly porous nonwoven framework. This is the first report of highly functional nylon-6 nonwovens, fabricated via industrially scalable pathways into low-cost conductive polymer matrices and disposable energy storage systems.

Physical Microfabrication of Shape-Memory Polymer Systems via Bicomponent Fiber Spinning.

As emerging technologies continue to require diverse materials capable of exhibiting tunable stimuli-responsiveness, shape-memory materials are of considerable significance because they can change size and/or shape in controllable fashion upon environmental stimulation. Of particular interest, shape-memory polymers (SMPs) have secured a central role in the ongoing development of relatively lightweight and remotely deployable devices that can be further designed with specific surface properties. In the case of thermally-activated SMPs, two functional chemical species must be present to provide (i) an elastic network capable of restoring the SMP to a previous strain state and (ii) switching elements that either lock-in or release a temporary strain at a well-defined thermal transition. While these species are chemically combined into a single macromolecule in most commercially available SMPs, this work establishes that, even though they are physically separated across one or more polymer/polymer interfaces, their shape-memory properties are retained in melt-spun bicomponent fibers. In the present study, we investigate the effects of fiber composition and cross-sectional geometry on both conventional and cold-draw shape memory, and report surprisingly high levels of strain fixity and recovery that generally improve upon strain cycling.

Evaluation of Silver Ion-Releasing Scaffolds in a 3D Coculture System of MRSA and Human Adipose-Derived Stem Cells for Their Potential Use in Treatment or Prevention of Osteomyelitis.

Bone infection, also called osteomyelitis, can result when bacteria invade a bone. Treatment of osteomyelitis usually requires surgical debridement and prolonged antimicrobial therapy. The rising incidence of infection with multidrug-resistant bacteria, in particular methicillin-resistant staphylococcus aureus (MRSA), however, limits the antimicrobial treatment options available. Silver is well known for its antimicrobial properties and is highly toxic to a wide range of microorganisms. We previously reported our development of biocompatible, biodegradable, nanofibrous scaffolds that released silver ions in a controlled manner. The objective of this study was to determine the efficacy of these scaffolds in treating or preventing osteomyelitis. To achieve this objective, antimicrobial efficacy was determined using a 3D coculture system of human adipose-derived stem cells (hASC) and MRSA. Human ASC were seeded on the scaffolds and induced to undergo osteogenic differentiation in both the absence and presence of MRSA. Our results indicated that the silver ion-releasing scaffolds not only inhibited biofilm formation, but also supported osteogenesis of hASC. Our findings suggest that these biocompatible, degradable, silver ion-releasing scaffolds can be used at an infection site to treat osteomyelitis and/or to coat bone implants as a preventative measure against infection postsurgery.