Pore Size Of Scaffolds Research Articles

Mechanical and Biological Behaviour of 3D Printed PCL-Based Scaffolds Fabricated by Fused Deposition Modelling for Bone Tissue Engineering: A Review of Recent Advances

The imperative need for alternative approaches to organ transplantation, replacing or regenerating damaged tissues is the key driving force for the remarkable development in tissue engineering. It can be precious in saving people who suffer from the critical shortage of organ donation. Such a strategy can repair injured body parts and tissues by using biomaterials, cells, and bioactive agents. Even though numerous scaffold manufacturing techniques have been available for bone regeneration, the three-dimensional (3D) printing approach can provide scaffolding with delicate features that may not be obtainable in other manufacturing strategies. For instance, when a 3D printer is used, it is possible to easily adjust scaffold pore architecture and size, porosity, and material alignment, forming customizable and defect-fillable scaffolds, which helps control the mechanical behavior of cellular response. The most prominent material used in scaffolding and printing is polycaprolactone (PCL), owing to its considerable potential and capabilities. It has favorable properties for the fabrication of bone tissue engineering scaffolds, such as biocompatibility, viscoelasticity, and affordability. Nonetheless, some inherent drawbacks of this polymer that limit its use in this field are detected, including inadequate mechanical performance, cell adhesion, osteoinductive deficiency, hydrophobicity, and low degradation rate. The incorporation of other materials within this polymer to form composites, on the other hand, can contribute to alleviating the negative influence of the PCL's undesirable characteristics. Improving the mechanical and biological behaviors of PCL-based scaffolds allows these structures to be utilized for tissue engineering since such composites can promote cell adhesion and differentiation, mimic anatomical characteristics of native bone, and can have superior mechanical performance. In this review, the latest advancements in printing intricate geometries 3D PCL-based composites using bioactive ceramics and/or biopolymers by fused deposition modeling (FDM) for bone tissue engineering will be explored, particularly from a morphological, mechanical, and biological perspective.

Extensive cell seeding densities adaptable SF/PGA electrospinning scaffolds for bone tissue engineering.

• The degradation behavior of SF/PGA scaffolds preserve their respective characteristics: the fast degradation of PGA made room for cell ingrowth, while the slow degradation of SF maintained scaffold structure and alleviated the acidity of PGA degradation products. • The extensive initial cell seeding density adaptability of electrospinning scaffolds with relatively large pore size helps to avoid cell source extravagance. • The study provides a first ever comprehensive comparative analysis between pore size of scaffold and initial cell seeding density and highlight the importance of pore size. • SF/PGA scaffold with pore size of 40.79 ± 13.71 μm shows superior cell activities in vitro and enhanced bone regeneration in vivo , which indicates it a suitable scaffold material in treatment of bone defect.

Pore Size of 3D-Printed Polycaprolactone/Polyethylene Glycol/Hydroxyapatite Scaffolds Affects Bone Regeneration by Modulating Macrophage Polarization and the Foreign Body Response.

3D-printed porous bioactive ceramic scaffolds have been widely used in bone defect repair. However, material implantation is often accompanied by a foreign body response (FBR), which may affect host tissue regeneration. The physical properties of biomaterials, including shape, pore size, and porosity, control the relevant immune responses during tissue regeneration. To the best of our knowledge, the effect of the pore size of 3D-printed scaffolds on the immune response and bone-biomaterial integration has not been studied in vivo. Polycaprolactone/polyethylene glycol/hydroxyapatite (PCL/PEG/HA) bioactive scaffolds with different pore sizes, including 209.9 ± 77.1 μm (P200), 385.5 ± 28.6 μm (P400), and 582.1 ± 27.2 μm (P600), were prepared with a pneumatic extrusion 3D printer. Compared with other pore sizes, P600 significantly reduced the FBR and induced more M2 macrophage infiltration, vascular ingrowth, and new bone formation. Immunohistochemical staining revealed that the MyD88 protein might be involved in macrophage polarization-related signal transduction in response to the pore size. Based on these results, bone regeneration requires the active participation of the immune response, and the P600 PCL/PEG/HA scaffold is a preferable candidate for the repair of bone defects.

Silk Fibroin-Based Biomaterials for Tissue Engineering Applications

Tissue engineering (TE) involves the combination of cells with scaffolding materials and appropriate growth factors in order to regenerate or replace damaged and degenerated tissues and organs. The scaffold materials serve as templates for tissue formation and play a vital role in TE. Among scaffold materials, silk fibroin (SF), a naturally occurring protein, has attracted great attention in TE applications due to its excellent mechanical properties, biodegradability, biocompatibility, and bio-absorbability. SF is usually dissolved in an aqueous solution and can be easily reconstituted into different forms, including films, mats, hydrogels, and sponges, through various fabrication techniques, including spin coating, electrospinning, freeze drying, and supercritical CO2-assisted drying. Furthermore, to facilitate the fabrication of more complex SF-based scaffolds, high-precision techniques such as micro-patterning and bio-printing have been explored in recent years. These processes contribute to the diversity of surface area, mean pore size, porosity, and mechanical properties of different silk fibroin scaffolds and can be used in various TE applications to provide appropriate morphological and mechanical properties. This review introduces the physicochemical and mechanical properties of SF and looks into a range of SF-based scaffolds that have recently been developed. The typical applications of SF-based scaffolds for TE of bone, cartilage, teeth and mandible tissue, cartilage, skeletal muscle, and vascular tissue are highlighted and discussed followed by a discussion of issues to be addressed in future studies.

Scaffold Pore Curvature Influences ΜSC Fate through Differential Cellular Organization and YAP/TAZ Activity.

Tissue engineering aims to repair, restore, and/or replace tissues in the human body as an alternative to grafts and prostheses. Biomaterial scaffolds can be utilized to provide a three-dimensional microenvironment to facilitate tissue regeneration. Previously, we reported that scaffold pore size influences vascularization and extracellular matrix composition both in vivo and in vitro, to ultimately influence tissue phenotype for regenerating cranial suture and bone tissues, which have markedly different tissue properties despite similar multipotent stem cell populations. To rationally design biomaterials for specific cell and tissue fate specification, it is critical to understand the molecular processes governed by cell-biomaterial interactions, which guide cell fate specification. Building on our previous work, in this report we investigated the hypothesis that scaffold pore curvature, the direct consequence of pore size, modulates the differentiation trajectory of mesenchymal stem cells (MSCs) through alterations in the cytoskeleton. First, we demonstrated that sufficiently small pores facilitate cell clustering in subcutaneous explants cultured in vivo, which we previously reported to demonstrate stem tissue phenotype both in vivo and in vitro. Based on this observation, we cultured cell-scaffold constructs in vitro to assess early time point interactions between cells and the matrix as a function of pore size. We demonstrate that principle curvature directly influences nuclear aspect and cell aggregation in vitro. Scaffold pores with a sufficiently low degree of principle curvature enables cell differentiation; pharmacologic inhibition of actin cytoskeleton polymerization in these scaffolds decreased differentiation, indicating a critical role of the cytoskeleton in transducing cues from the scaffold pore microenvironment to the cell nucleus. We fabricated a macropore model, which allows for three-dimensional confocal imaging and demonstrates that a higher principle curvature facilitates cell aggregation and the formation of a potentially protective niche within scaffold macropores which prevents MSC differentiation and retains their stemness. Sufficiently high principle curvature upregulates yes-associated protein (YAP) phosphorylation while decreased principle curvature downregulates YAP phosphorylation and increases YAP nuclear translocation with subsequent transcriptional activation towards an osteogenic differentiation fate. Finally, we demonstrate that the inhibition of the YAP/TAZ pathway causes a defect in differentiation, while YAP/TAZ activation causes premature differentiation in a curvature-dependent way when modulated by verteporfin (VP) and 1-oleyl-lysophosphatidic acid (LPA), respectively, confirming the critical role of biomaterials-mediated YAP/TAZ signaling in cell differentiation and fate specification. Our data support that the principle curvature of scaffold macropores is a critical design criterion which guides the differentiation trajectory of mesenchymal stem cells’ scaffolds. Biomaterial-mediated regulation of YAP/TAZ may significantly contribute to influencing the regenerative outcomes of biomaterials-based tissue engineering strategies through their specific pore design.

Particulate leaching improves spheroid formation in PEG and gelatin-based matrices for 3D tumor model

Spheroids have been developed and used as in vitro tumor models for various applications. However, the most commonly used hanging drop and liquid overlay methods to culture spheroids are challenging due to lack of sturdiness and reproducibility of spheroids and poor microenvironment mimicking features such as matrix stiffness and 3D architecture. Consequently, scaffold-based platforms to culture spheroids have gained momentum. It is already well established that scaffold features such as architecture, surface characteristics and mechanical properties influence the formation of spheroids. In present study, polyethylene glycol diacrylate (PEGDA) and gelatin methacryloyl (GelMA) based scaffolds were fabricated to provide a 3D microenvironment for melanoma spheroids, and pore size of scaffolds was found to be an important parameter influencing the spheroid size. In this study, we have demonstrated that fabricating matrices using a combination of particulate leaching using sodium chloride (NaCl) and freeze-drying enhances the pore size of scaffolds for subsequent formation of larger spheroids (~300 µm) required for various applications. PEGDA-GelMA matrix fabricated in this study provides a sturdy platform for scaffold-based spheroid formation and can be used for long-term culture of multicellular spheroids for development of in vitro tumor models.

Strategies to Control In Vitro Degradation of Mg Scaffolds Processed by Powder Metallurgy

Magnesium scaffolds are biodegradable, biocompatible, bioactive porous scaffolds, which find applications within tissue engineering. The presence of porosity increases surface area and enhances cell proliferation and tissue ingrowth. These characteristics make Mg scaffolds key materials to enhance the healing processes of tissues such as cartilage and bone. However, along with the increment of porosity, the corrosion of magnesium within a physiological environment occurs faster. It is, therefore, necessary to control the degradation rate of Mg scaffolds in order to maintain their mechanical properties during the healing process. Several studies have been performed to increase Mg scaffolds’ corrosion resistance. The different approaches include the modification of the Mg surface by conversion coatings or deposited coatings. The nature of the coatings varies from ceramics such as hydroxyapatite and calcium phosphates to polymers such as polycaprolactone or gelatin. In this work, we propose a novel approach to generating a protective bilayer coating on the Mg scaffold surface composed of a first layer of naturally occurring Mg corrosion products (hydroxide and phosphates) and a second layer of a homogeneous and biocompatible coating of polylactic acid. The Mg scaffolds were fabricated from Mg powder by means of powder metallurgy using ammonium bicarbonate as a space holder. The size and amount of porosity were controlled using different size distributions of space holders. We addressed the influence of scaffold pore size on the conversion and deposition processes and how the coating process influences the in vitro degradation of the scaffolds.

Three-dimensional printing of polycaprolactone/hydroxyapatite bone tissue engineering scaffolds mechanical properties and biological behavior

Controlled pore size and desirable internal architecture of bone scaffolds play a significant role in bone regeneration efficiency. In addition to choosing appropriate materials, the manufacturing method is another significant factor in fabricating the ideal scaffold. In this study, scaffolds were designed and fabricated by the fused filament fabrication (FFF) technique. Polycaprolactone (PCL) and composites films with various percentages of hydroxyapatite (HA) (up to 20%wt) were used to fabricate filaments. The influence of (HA) addition on the mechanical properties of filaments and scaffolds was investigated. in vitro biological evaluation was examined as well as the apatite formation in simulated body fluid (SBF). The addition of HA particles increased the compressive strength and Young’s modulus of filaments and consequently the scaffolds. Compared to PCL, Young’s modulus of PCL/HA20% filament and three-dimensional (3D) printed scaffold has increased by 30% and 50%, respectively. Also, Young’s modulus for all scaffolds was in the range of 30–70 MPa, which is appropriate to use in spongy bone. Besides, the MTT assay was utilized to evaluate cell viability on the scaffolds. All the samples had qualified cytocompatibility, and it would be anticipated that addition of HA particles raise the biocompatibility in vivo. Alkaline phosphatase (ALP) evaluation shows that the addition of HA caused higher ALP activity in the PCL/HA scaffolds than PCL. Furthermore, calcium deposition in the PCL/HA specimens is higher than control. In conclusion, the addition of HA particles into the PCL matrix, as well as utilizing an inexpensive commercial FFF device, lead to the fabrication of scaffolds with proper mechanical and biological properties for bone tissue engineering applications.Graphical abstract

The effect of different sizes of cross‐linked fibers of biodegradable electrospun poly(ε‐caprolactone) scaffolds on osteogenic behavior in a rat model in vivo

AbstractA variety of biodegradable polymer scaffolds serving the purpose of mimicking the extracellular matrix have been studied; however, no effective recipe has yet been developed for scaffold pore size and overall percent porosity, which are optimal for cell penetration in vitro and tissue growth in vivo. Thus, this study reports the effect of poly(ε‐caprolactone) (PCL) fiber size and scaffold porosity on the osteogenic behavior of scaffolds in a rat model in vivo. It was revealed that scaffolds with an average fiber size of 9.2 μm, and 4.05 μm, and combination of 0.6 μm submicrofibres (upper layer) with 9.2 μm microfibres (bottom layer) in hybrid two‐layer scaffolds behave significantly differently with respect to macrophage reactions and tissue regeneration in a rat model in vivo. Poor macrophage response at implantation tests into the bone tissue in vivo reveals the advantages of microfibrous PCL scaffolds with a fiber size of 4.05 μm and hybrid scaffolds with submicro‐ and microfibres for stimulation of reparative osteogenesis over microfibrous scaffolds with a fiber size of 9.2 μm. The combination of submicro‐ and microfibrous layers in hybrid scaffolds provides an opportunity to control the shape and density of bone trabeculae during regeneration processes in vivo.

Mechanical stability and biological activity of Mg–Sr co-doped bioactive glass/chitosan composite scaffolds

The freeze-drying method was used to synthesize biological scaffold. The properties of the as-prepared scaffolds were investigated by various techniques. Results showed that the magnesium (Mg) and strontium (Sr) co-doped bioactive glass/chitosan (MSBG/CS) composite scaffolds exhibited a three-dimensional honeycombed porous structure. With the increase in the added content of MSBG powders, the porosity, average pore size, swelling, and degradation rate of composite scaffolds decreased gradually. When the mass ratio of MSBG to CS was 2:4, compressive modulus of composite scaffold reached the maximum value of 1.12±0.019 MPa. It could be attributed to the hydrogen bond between the negatively charged silicon hydroxyl (Si–OH) in MSBG and positively charged amino group (–NH2) in CS molecular chain. In vitro experiment indicates that MSBG could significantly improve the generation capacity of hydroxyapatite in composite scaffold. Thus, the as-formed composite scaffold with remarkable performance acts as a promising candidate for bone tissues engineering.

The contribution of pore size and porosity of 3D printed porous titanium scaffolds to osteogenesis

Porous titanium implants were popularly fabricated to promote bone formation. A desirable porous scaffold was recommended to be with porosity of >60% or/and pore size of >300 μm for better osteointegration. However, whether the pore size and porosity could be randomly selected within the recommended values? And what is the correlation between pore size and porosity for accelerating osteointegration? In this study, porous titanium with cubic cell structure was produced by selective laser melting. The designed porosities of scaffolds with 700-μm pore size were 40%, 70% and 90%; and the pore sizes of scaffolds with 70% porosity were 400, 700 and 900 μm. The in vitro osteogenic potential and in vivo bone formation were investigated. Results showed that porosity and pore size could be tuned by altering strut size, which was further directly responsible for mechanical properties. Besides, pore size and porosity synergistically contributed to osteogenic activity in vitro and new bone formation in vivo. In regard to pore sizes herein, the optimized one for better osteogenic response and bone forming ability was ~600–700 μm (p70). Too smaller or too larger pore size might more or less hinder cellular behaviors and bone regeneration, even if both pore size (300–900 μm) and porosity (70%) were within the recommended value range. At a constant pore size (~600–700 μm), p70 and p90 with higher porosity was more conductive to biological effects, compared with p40. As a result, pore-size variation revealed more significant influence on osteogenesis, compared with variation of porosity within recommended values. However, the applicable porosity within recommended values should be designed with the consideration of specific load-bearing conditions. This study helps to provide guidance for designing porous scaffolds with appropriate mechanical strengths and effective bone-forming ability, so as to develop better custom-made bone substitutes.

Hydrogel composite scaffolds achieve recruitment and chondrogenesis in cartilage tissue engineering applications

BackgroundThe regeneration and repair of articular cartilage remains a major challenge for clinicians and scientists due to the poor intrinsic healing of this tissue. Since cartilage injuries are often clinically irregular, tissue-engineered scaffolds that can be easily molded to fill cartilage defects of any shape that fit tightly into the host cartilage are needed.MethodIn this study, bone marrow mesenchymal stem cell (BMSC) affinity peptide sequence PFSSTKT (PFS)-modified chondrocyte extracellular matrix (ECM) particles combined with GelMA hydrogel were constructed.ResultsIn vitro experiments showed that the pore size and porosity of the solid-supported composite scaffolds were appropriate and that the scaffolds provided a three-dimensional microenvironment supporting cell adhesion, proliferation and chondrogenic differentiation. In vitro experiments also showed that GelMA/ECM-PFS could regulate the migration of rabbit BMSCs. Two weeks after implantation in vivo, the GelMA/ECM-PFS functional scaffold system promoted the recruitment of endogenous mesenchymal stem cells from the defect site. GelMA/ECM-PFS achieved successful hyaline cartilage repair in rabbits in vivo, while the control treatment mostly resulted in fibrous tissue repair.ConclusionThis combination of endogenous cell recruitment and chondrogenesis is an ideal strategy for repairing irregular cartilage defects.Graphical

Applications of electrospun scaffolds with enlarged pores in tissue engineering.

Despite electrospinning having multiple advantages over other methods such as creating materials with a superfine fiber diameter, high specific surface area, and good mechanical properties, the pore diameter of scaffolds prepared directly using conventional electrospinning is often smaller than a few tens of microns, which may not be suitable for three-dimensional (3-D) cell culture and tissue growth. In order to achieve satisfactory results for use in tissue engineering, the pore size of the scaffold should be increased to a size dependent on the specific cells being cultured. Many methods for enlarging the pore size of electrospun scaffolds have been described in the literature. In the present review, we have summarized the preparation of macroporous electrospun scaffold techniques for the skin, blood vessels, bone, cartilage and nerve tissue engineering for different applications, and further discuss the influence of changing pore-enlarging process parameters on the properties of the scaffolds, such as mechanical properties, and hydrophilicity and hydrophobicity, etc. We believe that changes in scaffold pore size and related physical properties can have a profound impact on cell behavior, such as adhesion, proliferation and infiltration, and the significance of their influence on applications of electrospun tissue engineering scaffolds is worthy of further investigation in the future.

Preparation of the bioglass/chitosan-alginate composite scaffolds with high bioactivity and mechanical properties as bone graft materials

Bioglass/chitosan-alginate (BCA) composite scaffolds with remarkable performance for bone tissue engineering are successfully prepared by freeze-drying method. The influence of the addition amount of sodium alginate (SA) on the microstructure, porosity, pore size, swelling ratio, degradation ratio, mechanical properties and mineralization ability of BCA composite scaffolds is studied and characterized by various techniques of the scanning electron microscopy, X-ray diffraction, infrared absorption spectrometer and so on. The results show that the BCA composite scaffolds have the three-dimensional interconnected network structure with the high porosity of 82%–87% and a suitable average pore size of 140–200 μm. With the increase of SA addition, the porosity and pore size of BCA gradually reduced and the thickness of pore wall increased. The swelling and degradation ratios decreased gradually with the raising SA and increased with the prolongation of soaking time in PBS. The mechanical strength of BCA was also significantly enhanced, and the mineralization ability of bioglass was effectively deployed with the adding SA of BCA. The improved performance of BCA may be attributed to the formed 3D network structure, activated bioavailability and crosslinking ability between chitosan and SA. It indicates that BCA composite scaffolds have potential applications in bone issues engineering.

PoreScript: Semi-automated pore size algorithm for scaffold characterization

The scaffold pore size influences many critical physical aspects of tissue engineering, including tissue infiltration, biodegradation rate, and mechanical properties. Manual measurements of pore sizes from scanning electron micrographs using ImageJ/FIJI are commonly used to characterize scaffolds, but these methods are both time-consuming and subject to user bias. Current semi-automated analysis tools are limited by a lack of accessibility or limited sample size in their verification process. The work here describes the development of a new MATLAB algorithm, PoreScript, to address these limitations. The algorithm was verified using three common scaffold fabrication methods (e.g., salt leaching, gas foaming, emulsion templating) with varying pore sizes and shapes to demonstrate the versatility of this new tool. Our results demonstrate that the pore size characterization using PoreScript is comparable to manual pore size measurements. The PoreScript algorithm was further evaluated to determine the effect of user-input and image parameters (relative image magnification, pixel intensity threshold, and pore structure). Overall, this work validates the accuracy of the PoreScript algorithm across several fabrication methods and provides user-guidance for semi-automated image analysis and increased throughput of scaffold characterization.

Microstructure, shape memory properties, and in vitro biocompatibility of porous NiTi scaffolds fabricated via selective laser melting

In this study, three porous NiTi scaffolds with the same porosity but different pore sizes (900, 835, and 618 μm) were fabricated via selective laser melting (SLM). The microstructure, mechanical properties, shape memory properties, and in vitro biocompatibility of the different porous NiTi scaffolds were studied systematically by scanning electron microscopy, micro-computed tomography, differential scanning calorimetry, compressive testing, and in vitro cell culture experiments. The pore sizes of the SLM porous NiTi scaffolds were smaller than those of computer-aided design models owing to the existence of spatter powders, whereas the strut diameters showed the opposite tendency. Furthermore, the elastic modulus of the three NiTi scaffolds was close to that of human bones and lower than that of most previously reported porous NiTi and Ti alloys with similar porosities. Moreover, the scaffolds demonstrated better compressive strength than that of most of the reported porous NiTi alloys with similar porosities as well as better strength and fracture strain than those of human bones, particularly for scaffolds with larger pore sizes. Moreover, the best recoverable strain of 5.10% and recovery rate of 91.4% were obtained for porous NiTi scaffolds with a pore size of 900 μm owing to their minimal stress concentration during loading. The in vitro study further demonstrated that a relatively small pore size could promote the bridging growth of cells in pores, and the in vitro biocompatibility of the porous NiTi scaffolds was equivalent to that of bulk SLM NiTi. The results obtained in this study can provide guidance for the application of porous NiTi scaffolds in biological implants.

Large-pore-size Ti6Al4V scaffolds with different pore structures for vascularized bone regeneration

Porous Ti6Al4V scaffolds are characterized by high porosity, low elastic modulus, and good osteogenesis and vascularization, which are expected to facilitate the repair of large-scale bone defects in future clinical applications. Ti6Al4V scaffolds are divided into regular and irregular structures according to the pore structure, but the pore structure more capable of promoting bone regeneration and angiogenesis has not yet been reported. The purpose of this study was to explore the optimal pore structure and pore size of the Ti6Al4V porous scaffold for the repair of large-area bone defects and the promotion of vascularization in the early stage of osteogenesis. 7 groups of porous Ti6Al4V scaffolds, named NP, R8, R9, R10, P8, P9 and P10, were fabricated by Electron-beam-melting (EBM). Live/dead staining, immunofluorescence staining, SEM, CCK8, ALP, and PCR were used to detect the adhesion, proliferation, and differentiation of BMSCs on different groups of scaffolds. Hematoxylin-eosin (HE) staining and Van Gieson (VG) staining were used to detect bone regeneration and angiogenesis in vivo. The research results showed that as the pore size of the scaffold increased, the surface area and volume of the scaffold gradually decreased, and cell proliferation ability and cell viability gradually increased. The ability of cells to vascularize on scaffolds with irregular pore sizes was stronger than that on scaffolds with regular pore sizes. Micro-CT 3D reconstruction images showed that bone regeneration was obvious and new blood vessels were thick on the P10 scaffold. HE and VG staining showed that the proportion of bone area on the scaffolds with irregular pores was higher than that on scaffolds with regular pores. P10 had better mechanical properties and were more conducive to bone tissue ingrowth and blood vessel formation, thereby facilitating the repair of large-area bone defects.

Biopolymer Hydrogel Scaffolds Containing Doxorubicin as A Localized Drug Delivery System for Inhibiting Lung Cancer Cell Proliferation.

A hydrogel scaffold is a localized drug delivery system that can maintain the therapeutic level of drug concentration at the tumor site. In this study, the biopolymer hydrogel scaffold encapsulating doxorubicin was fabricated from gelatin, sodium carboxymethyl cellulose, and gelatin/sodium carboxymethyl cellulose mixture using a lyophilization technique. The effects of a crosslinker on scaffold morphology and pore size were determined using scanning electron microscopy. The encapsulation efficiency and the release profile of doxorubicin from the hydrogel scaffolds were determined using UV-Vis spectrophotometry. The anti-proliferative effect of the scaffolds against the lung cancer cell line was investigated using an MTT assay. The results showed that scaffolds made from different types of natural polymer had different pore configurations and pore sizes. All scaffolds had high encapsulation efficiency and drug-controlled release profiles. The viability and proliferation of A549 cells, treated with gelatin, gelatin/SCMC, and SCMC scaffolds containing doxorubicin significantly decreased compared with control. These hydrogel scaffolds might provide a promising approach for developing a superior localized drug delivery system to kill lung cancer cells.

Nanofiber configuration affects biological performance of decellularized meniscus extracellular matrix incorporated electrospun scaffolds

Electrospinning represents the simplest approach to fabricate nanofiber scaffolds that approximate the heterogeneous fibrous structure of the meniscus. More effort is needed to understand the relationship between scaffold properties and cell responses to determine the appropriate scaffolds supporting meniscus tissue repair and regeneration. In this study, we investigate the influence of nanofiber configuration of electrospun scaffolds on phenotype and matrix production of meniscus cells, as well as on scaffold degradation behaviors and biocompatibility. Twisting electrospun nanofibers into yarns not only recapitulates the major collagen bundles of the meniscus but also increases the pore size and porosity of resultant scaffolds. The yarn scaffold significantly regulated expression levels of meniscus-associated genes and promoted extracellular matrix production compared with conventional electrospun scaffolds with random or aligned nanofiber orientation. Additionally, the yarn scaffold allowed considerable cell infiltration and experienced faster degradation and tissue remodeling upon subcutaneous implantation in a rat model. These results suggest that nanofiber configuration dictates cell interactions, scaffold degradation and integration with host tissue, providing design parameters of porosity and pore size of electrospun scaffolds toward meniscus repair.

Synthesis and Characterization of Electrospun Polyvinylidene Fluoride-based (PVDF) Scaffolds for Renal Bioengineering

With the continuous search for alternative treatment for End Stage Renal Disease (ESRD), the use of synthetic scaffolds as a prospect is becoming a forefront in regenerative medicine. This study aimed to fabricate and evaluate the effects of varying electrospinning parameters (the applied voltage, spinning distance and flowrate) to the fiber diameter and pore size of the scaffolds produced using polyvinylidene fluoride (PVDF). Electrospun scaffolds were subjected to scanning electron microscopy (SEM) and strain apparatus to assess structural and tensile properties. Results showed that applied voltage, spinning distance, and flowrate directly affect the overall pore size and fiber diameter of the electrospun scaffolds, as well as resulting in a direct effect to the tensile strength of the electrospun scaffold. The optimal values for the parameters in fabricating a PVDF electrospun scaffold would be a voltage of 20kV, a spinning distance of 100mm and a flowrate of 0.5ml/h. Results also show that spinning distance and flowrate have statistically more impact on the outcome of the fiber diameters, while applied voltage and spinning have statistically more impact on the outcome of the pore sizes. Moreover, the electrospun scaffolds acquired thinner fiber diameters and smaller pores sizes when compared to that of the native kidney tissue. Nonetheless, the promising mechanical integrity of the electrospun PVDF-based scaffolds offer a potential approach to addressing ESRD.