Pore Size Of Scaffolds Research Articles

Potential In Vitro Tissue-Engineered Anterior Cruciate Ligament by Copolymerization of Polyvinyl Alcohol and Collagen.

Suitable tissue-engineered scaffolds to replace human anterior cruciate ligament (ACL) are well developed clinically as the development of tissue engineering. As water-soluble polymer compound, polyvinyl alcohol (PVA) has been wildly used as the materials to replace ACL. The aim of this study was to explore the feasibility of constructing tissue-engineered ACL by the copolymerization of PVA and collagen (PVA/COL). PVA and COL were copolymerized at a mass ratio of 3:1. The pore size and porosity of the scaffold were observed by electron microscope. The maximum tensile strength of the scaffold was determined by electronic tension machine. The cytotoxicity of the scaffold was evaluated by MTT assay. The morphology of ACL cells cultured on the surface of the scaffold was observed by inverted microscope. The degradation of the scaffold was recorded in the rabbit model. The average pore size of the polymer scaffold was 100 to 150 μm and the porosity was about 90%. The maximum tensile strength of the scaffold material was 8.10 ± 0.28 MPa. PVA/COL could promote the proliferation ability of 3T3 cells. ACL cells were successfully cultured on the surface of PVA/COL scaffold, with natural growth rate, differentiation, and proliferation. Twenty-four weeks after the plantation of scaffold, obvious degradations were observed in vivo. The model of in-vitro tissue-engineered ACL was successfully established by PVA/COL scaffolds.

Comparative analysis of TiO2 and Ag nanoparticles on xylan/chitosan conjugate matrix for wound healing application

Our present study evaluates the performance of wound dressing material fabricated by incorporating silver(Ag) and titanium dioxide(TiO2) nanoparticles(NPs) in xylan/chitosan-based conjugate matrix. The porous nanocomposites were examined for antimicrobial, cell attachment, swelling, protein adsorption, and cytotoxic studies. Nanocomposites exhibited potent antimicrobial response against both gram-negative and gram-positive strains of bacteria. Despite remarkable cellular response, a concentration-dependent cytotoxicity was observed in matrix with high Ag NPs content. Nanoparticles incorporated composites also tuned the pore size, swelling ratio, and protein adsorption tendency of scaffold making them feasible as wound dressing material.

3D-Printed Ceramic Bone Scaffolds with Variable Pore Architectures.

This study evaluated the mechanical properties and bone regeneration ability of 3D-printed pure hydroxyapatite (HA)/tricalcium phosphate (TCP) pure ceramic scaffolds with variable pore architectures. A digital light processing (DLP) 3D printer was used to construct block-type scaffolds containing only HA and TCP after the polymer binder was completely removed by heat treatment. The compressive strength and porosity of the blocks with various structures were measured; scaffolds with different pore sizes were implanted in rabbit calvarial models. The animals were observed for eight weeks, and six animals were euthanized in the fourth and eighth weeks. Then, the specimens were evaluated using radiological and histological analyses. Larger scaffold pore sizes resulted in enhanced bone formation after four weeks (p < 0.05). However, in the eighth week, a correlation between pore size and bone formation was not observed (p > 0.05). The findings showed that various pore architectures of HA/TCP scaffolds can be achieved using DLP 3D printing, which can be a valuable tool for optimizing bone-scaffold properties for specific clinical treatments. As the pore size only influenced bone regeneration in the initial stage, further studies are required for pore-size optimization to balance the initial bone regeneration and mechanical strength of the scaffold.

The pore size of chitosan-Aloe vera scaffold and its effect on VEGF expressions and woven alveolar bone healing of tooth extraction of Cavia cobaya

Background: Pore size of scaffolds affects cellular activity, stimulates angiogenetic factors of vascular endothelial growth factor (VEGF), synthesises new blood vessels to regulate migration and proliferation, and accelerates alveolar bone healing of tooth extraction. Purpose: This study aims to analyse the pore size of chitosan-Aloe vera scaffold and its effects on VEGF expression and woven alveolar bone healing of tooth extraction of Cavia cobaya. Methods: 36 male Cavia cobaya, aged 3-3.5 months were divided into six groups: negative control groups (without scaffold), positive control groups (chitosan scaffold), and treatment groups (chitosan-Aloe vera scaffold) on 7- and 14-day observations. Histopathological examination was performed to account the woven alveolar bone areas, and immunohistochemical examination was conducted to examine VEGF expressions on endothelial cells. Data was analysed using a one-way analysis of variance (ANOVA) and least significant difference (LSD) test (p&lt;0.05). Scaffold pore size examination was performed with scanning electron microscope (SEM) with 250x and 500x magnification. Results: Chitosan-Aloe vera scaffold was found to have open pore interconnectivity, the largest pore size was 138.9 μm, while the smallest was 110.5 μm and average pore size was 134.85 μm. The highest expression of VEGF was observed in the treatment group on days 7 (11.5 ±1.39) and 14 (15.28±1.78), while the largest woven alveolar bone was observed in the treatment group on days 7(17.83±1.47) and 14 (37.67±3.65). Statistically, there was a significant difference between control groups and the treatment groups (p=0.000; p&lt;0.05). Conclusion: Chitosan-Aloe vera scaffold has pore characteristics increasing VEGF expressions and woven alveolar bone areas.

Radiation-crosslinked scaffolds from gelatin/CM-chitin and gelatin/CM-chitosan hydrogels for adipose-derived stem cell culture

Radiation technology has been providing a useful tool to modify polymers involving the radiation crosslinking of hydrogels. In the present work, two kinds of hydrogels composed gelatin and carboxymethyl chitosan (gelatin/CM-chitosan), and carboxymethyl chitin (gelatin/CM-chitin) were prepared by the radiation crosslinking. The resulting hydrogels were freeze-dried, sterilized under gamma-ray at a sterilization dose of 25 kGy, and characterized to be utilized as the scaffolds for culturing adipose-derived stem cells (hADSCs). The physicochemical properties, biodegradability, and cytotoxicity of these scaffolds were also investigated. The results indicated that both CM-chitosan and CM-chitin much improved the swelling capacity, porosity, and pore size of the gelatin-derived scaffolds. The swelling degree of gelatin/CM-chitosan and gelatin/CM-chitin scaffolds was about 7-9 g/g after 6 hrs immerging in PBS, and their porosity was about 70-73% with pore size ranging from 100 to 300 mm. The results also revealed that the compressive modulus of gelatin/CM-chitosan and gelatin/CM-chitin was 45.6 and 66.4 kPa, respectively, which were suitable for soft tissue engineering. Both scaffolds were enzymatically biodegradable by collagenase and non-cytotoxic for hADSCs with an RGR of ~97%. Thus, the resultant scaffolds can be suitably utilized for culturing hADSC in practice to regenerate soft tissues.

Scaffold Architecture and Matrix Strain Modulate Mesenchymal Cell and Microvascular Growth and Development in a Time Dependent Manner.

Volumetric tissue-engineered constructs are limited in development due to the dependence on well-formed vascular networks. Scaffold pore size and the mechanical properties of the matrix dictates cell attachment, proliferation and successive tissue morphogenesis. We hypothesize scaffold pore architecture also controls stromal-vessel interactions during morphogenesis. The interaction between mesenchymal stem cells (MSCs) seeded on hydroxyapatite scaffolds of 450, 340, and 250μm pores and microvascular fragments (MVFs) seeded within 20mg/mL fibrin hydrogels that were cast into the cell-seeded scaffolds, was assessed in vitro over 21days and compared to the fibrin hydrogels without scaffold but containing both MSCs and MVFs. mRNA sequencing was performed across all groups and a computational mechanics model was developed to validate architecture effects on predicting vascularization driven by stiffer matrix behavior at scaffold surfaces compared to the pore interior. Lectin staining of decalcified scaffolds showed continued vessel growth, branching and network formation at 14days. The fibrin gel provides no resistance to spread-out capillary networks formation, with greater vessel loops within the 450μm pores and vessels bridging across 250μm pores. Vessel growth in the scaffolds was observed to be stimulated by hypoxia and successive angiogenic signaling. Fibrin gels showed linear fold increase in VEGF expression and no change in BMP2. Within scaffolds, there was multiple fold increase in VEGF between days 7 and 14 and early multiple fold increases in BMP2 between days 3 and 7, relative to fibrin. There was evidence of yap/taz based hippo signaling and mechanotransduction in the scaffold groups. The vessel growth models determined by computational modeling matched the trends observed experimentally. The differing nature of hypoxia signaling between scaffold systems and mechano-transduction sensing matrix mechanics were primarily responsible for differences in osteogenic cell and microvessel growth. The computational model implicated scaffold architecture in dictating branching morphology and strain in the hydrogel within pores in dictating vessel lengths.

The effect of pore diameter on neo-tissue formation in electrospun biodegradable tissue-engineered arterial grafts in a large animal model

To date, there has been little investigation of biodegradable tissue engineered arterial grafts (TEAG) using clinically relevant large animal models. The purpose of this study is to explore how pore size of electrospun scaffolds can be used to balance neoarterial tissue formation with graft structural integrity under arterial environmental conditions throughout the remodeling process. TEAGs were created with an outer poly-ε-caprolactone (PCL) electrospun layer and an inner sponge layer composed of heparin conjugated 50:50 poly (l-lactide-co-ε-caprolactone) copolymer (PLCL). Outer electrospun layers were created with four different pore diameters (4, 7, 10, and 15 µm). Fourteen adult female sheep underwent bilateral carotid artery interposition grafting (n = 3–4 /group). Our heparin-eluting TEAG was implanted on one side (n = 14) and ePTFE graft (n = 3) or non-heparin-eluting TEAG (n = 5) on the other side. Twelve of the fourteen animals survived to the designated endpoint at 8 weeks, and one animal with 4 µm pore diameter graft was followed to 1 year. All heparin-eluting TEAGs were patent, but those with pore diameters larger than 4 µm began to dilate at week 4. Only scaffolds with a pore diameter of 4 µm resisted dilation and could do so for up to 1 year. At 8 weeks, the 10 µm pore graft had the highest density of cells in the electrospun layer and macrophages were the primary cell type present. This study highlights challenges in designing bioabsorbable TEAGs for the arterial environment in a large animal model. While larger pore diameter TEAGs promoted cell infiltration, neotissue could not regenerate rapidly enough to provide sufficient mechanical strength required to resist dilation. Future studies will be focused on evaluating a smaller pore design to better understand long-term remodeling and determine feasibility for clinical use. Statement of SignificanceIn situ vascular tissue engineering relies on a biodegradable scaffold that encourages tissue regeneration and maintains mechanical integrity until the neotissue can bear the load. Species-specific differences in tissue regeneration and larger mechanical forces often result in graft failure when scaling up from small to large animal models. This study utilizes a slow-degrading electrospun PCL sheath to reinforce a tissue engineered arterials graft. Pore size, a property critical to tissue regeneration, was controlled by changing PCL fiber diameter and the resulting effects of these properties on neotissue formation and graft durability was evaluated. This study is among few to report the effect of pore size on vascular neotissue formation in a large animal arterial model and also demonstrate robust neotissue formation.

Effect of hierarchical porous scaffold on osteoimmunomodulation and bone formation

The immune system plays an indispensable role in the process of tissue regeneration following scaffold implantation. Macrophages are one of the key immune cells in regeneration, and their depletion inhibits blastema granulation tissue formation and tissue repair. Increasing evidence indicates that different pore sizes of scaffolds can affect macrophage polarization and tissue regeneration. However, the accurate disciplinary is still misty. To address these issues, we sought to explore how diverse apertures affected the response of macrophages and the subsequent bone regeneration. We designed three types of hierarchical porous scaffolds with diverse pore combinations based on PLGA, bioactive glass (BG) and mesoporous bioactive glass (MBG). Each scaffold has the same composition but disparate porous structure: simplex PB-1 scaffold with conventional macro pores, dual-structured PMB-2 scaffold with macro‑meso pores, and the ternary combinational structured PMB-3 scaffold with macro-micro‑meso pores. We found the hierarchical PMB-3 scaffolds drove macrophages to significantly polarize towards M1 at early stage (0~3 days), while significantly reduced M1 polarization and increased M2 polarization at later stage (3~7 days). This fast-responsive feature can evoke resonate fluctuation of relevant pro-inflammatory and anti-inflammatory genes and cytokines. Moreover, enhanced angiogenic potential of HUVECs and osteogenic capacity of BMSCs were acquired by ternary PMB-3 scaffolds. Further in vivo implantations in mice demonstrated the immune microenvironment induced by PMB-3 scaffolds promoted the optimal neovascularization and ectopic bone formation. These findings indicated that scaffolds with complex macro-micro‑meso porous structure facilitated bone regeneration by endowing favorable osteoimmunomodulatory properties.

Promotion of Osseointegration between Implant and Bone Interface by Titanium Alloy Porous Scaffolds Prepared by 3D Printing.

Titanium alloy prostheses have been widely used for the treatment of orthopedic diseases, in which the interconnected porosity and appropriate pore size are crucial for the osseointegration capacity. Three-dimensional (3D) printing technology provides an efficient method to construct prosthesis scaffolds with controllable internal and surface structure, but printing high-porosity (>60%) scaffolds with pore diameters below 300 μm as implants structures has not yet been studied. In this work, four types of titanium alloy scaffolds with interconnected porosity more than 70% were successfully prepared by selective laser melting (SLM). The actual mean pore sizes of cylindrical scaffolds are 542, 366, 202, and 134 μm. Through the in vitro characterization of the scaffolds, in vivo experiments, and mechanical experiments, it is concluded that as the scaffold pore diameter decreases, the titanium alloy scaffold with diameter of 202 μm has the strongest osseointegration ability and is also the most stable one with the surrounding bone. These findings provide a reference for the clinical pore-size design of porous scaffolds with optimal bone growth stability on the surface of the titanium alloy implant.

Enzyme Scaffolds with Hierarchically Defined Properties via 3D Jet Writing.

The immobilization of enzymes into polymer hydrogels is a versatile approach to improve their stability and utility in biotechnological and biomedical applications. However, these systems typically show limited enzyme activity, due to unfavorable pore dimensions and low enzyme accessibility. Here, 3D jet writing of water-based bioinks, which contain preloaded enzymes, is used to prepare hydrogel scaffolds with well-defined, tessellated micropores. After 3D jet writing, the scaffolds are chemically modified via photopolymerization to ensure mechanical stability. Enzyme loading and activity in the hydrogel scaffolds is fully retained over 3 d. Important structural parameters of the scaffolds such as pore size, pore geometry, and wall diameter are controlled with micrometer resolution to avoid mass-transport limitations. It is demonstrated that scaffold pore sizes between 120µm and 1mm can be created by 3D jet writing approaching the length scales of free diffusion in the hydrogels substrates and resulting in high levels of enzyme activity (21.2% activity relative to free enzyme). With further work, a broad range of applications for enzyme-laden hydrogel scaffolds including diagnostics and enzymatic cascade reactions is anticipated.

Validation of the optimal scaffold pore size of nasal implants using the 3-dimensional culture technique.

BackgroundTo produce patient-specific nasal implants, it is necessary to harvest and grow autologous cartilage. It is crucial to the proliferation and growth of these cells for scaffolds similar to the extracellular matrix to be prepared. The pore size of the scaffold is critical to cell growth and interaction. Thus, the goal of this study was to determine the optimal pore size for the growth of chondrocytes and fibroblasts.MethodsPorous disc-shaped scaffolds with 100-, 200-, 300-, and 400-µm pores were produced using polycaprolactone (PCL). Chondrocytes and fibroblasts were cultured after seeding the scaffolds with these cells, and morphologic evaluation was performed on days 2, 14, 28, and 56 after cell seeding. On each of those days, the number of viable cells was evaluated quantitatively using an MTT assay.ResultsThe number of cells had moderately increased by day 28. This increase was noteworthy for the 300- and 400-µm pore sizes for fibroblasts; otherwise, no remarkable difference was observed at any size except the 100-µm pore size for chondrocytes. By day 56, the number of cells was observed to increase with pore size, and the number of chondrocytes had markedly increased at the 400-µm pore size. The findings of the morphologic evaluation were consistent with those of the quantitative evaluation.ConclusionsExperiments using disc-type PCL scaffolds showed (via both morphologic and quantitative analysis) that chondrocytes and fibroblasts proliferated most extensively at the 400-µm pore size in 56 days of culture.

Injectable Bone Substitute Paste Based on Hydroxyapatite, Gelatin and Streptomycin for Spinal Tuberculosis

World Health Organization (WHO) in 2005 reported that cases of tuberculosis (TB) in the world occur more than 8 million annually and 5-10% were attacked in spine. The most effective treatment of spinal TB is evacuation of infected bone segments and fill with bone graft. It has been synthesized and characterized of injectable bone substitute (IBS) paste based on hydroxyapatite, gelatin and streptomycin. IBS paste synthesized by mixing hydroxyapatite and gelatin 20% w/v with 75:25, 70:30, 65:35 and 60:40 ratio and streptomycin 10 wt%. The mixture was then added with hydroxypropyl methylcellulose (HPMC) 4% w/v as suspending agent. In vitro characterization performed include acidity (pH), injectability test, setting time, cytotoxicity (MTT assay) and microbacterium test. Acidity test results indicate a fourth variation of the samples had pH values approaching normal body pH (7,3 to 7,6) and is able to maintain stability when measured in 7 days. Injectability test results indicate IBS paste is injectable with the highest percentage of the injectability value at 97,74% ± 0,19%. IBS paste has been setting within 30 minutes to 1 hour when injected on hydroxyapatite scaffold that resembles the bone cavity and is able to cover the pore scaffold seen from the Scanning Electron Microscope (SEM). Scaffold pore size is smaller from range of 780,8 to 835,4 μm into 225,2 μm. MTT assay results showed that IBS paste is not toxic and experiencing proliferation (viability &gt;100%) that are expected to trigger osteoblast cell growth when applied. Microbacterium test results showed that IBS paste is an antibacterial seen from inhibition zone diameter of Staphylococcus aureus and has a high strength-sensitive antibacterial. Thus, hydroxyapatite, gelatin and streptomycin composites had qualified as injectable bone substitute which applied in cases of spinal tuberculosis.

Biodegradable poly (lactic acid-co-trimethylene carbonate)/chitosan microsphere scaffold with shape-memory effect for bone tissue engineering

Poly (lactic acid) (PLA), although extensively used as biomedical materials, has the distinct disadvantage of producing acidic byproducts which can lead to tissue inflammatory reactions and clinic failure. Here we presented a combination of Poly (lactic acid-co-trimethylene carbonate) and natural polymer chitosan, improving its compression resilience and reducing its acidic byproducts. In this case, we developed 3D scaffolds using solvent/nonsolvent technique sintered PLA-TMC and PLA-TMC/Chitosan microspheres with selected particle size (355−500 μm). By controlling the preparation methods and parameters, the porosity, pore size and mechanical properties of microsphere scaffolds can be designed and controlled. Strikingly, PLA-TMC/15 % Chitosan microsphere scaffolds possess shape-memory effect and rapidly recovered to initial shape when heated to 37℃ within 300 s. The microsphere scaffolds had a 3D porous architecture with pore size ranging from 105.67 ± 12.51 μm to 129.69 ± 11.39 μm. The mechanical and physicochemical properties of microspheres and scaffolds were characterized in details. Moreover, all microsphere scaffolds were qualified as their compressive modulus (120.36 MPa -195.32 MPa) matched the cancellous bone during 16 weeks degradation. Furthermore, CCK8 cell proliferation assay and ALP activity assay verified that the scaffolds were non-toxic and conductive to cell adhesion. The scaffolds are expected to be used in bone regeneration and bone repair field.

Structural analysis of porous bioactive glass scaffolds using micro-computed tomographic images

Three-dimensional structural properties such as pore size, interconnectivity, and tortuosity of scaffold play an essential role in bone tissue regeneration. We report the structural characterization of bioactive glass-based scaffolds by employing micro-computed tomography (µCT) imaging. µCT images were filtered and binarized to get 3D reconstruction of the scaffold. Fast march method was applied on 3D reconstructed scaffold to estimate tortuosity. Further, Canny edge detection algorithm was used to identify pore boundaries. Graph traversal algorithm was used to identify pore networks as open, close, and through. Pore and minimum throat size for a through path were quantified using equivalent circle diameter based on ASTM F2603-06. The porosity (66.69%), mean pore size (443 µm), mean pore throat diameter (131 µm), and tortuosity in different planes (~ 1) imply suitability of the scaffold for bone tissue engineering. Any porous sample can be characterized by the methodology directly with µCT or other imaging techniques.

Comparison of Chondrocytes in Knee Osteoarthritis and Regulation by Scaffold Pore Size and Stiffness.

In knee osteoarthritis (OA), there is more pronounced cartilage damage in the medial compartment ("lesion zone") than the lateral compartment ("remote zone"). This study fills a gap in the literature by conducting a systematic comparison of cartilage and chondrocyte characteristics from these two zones. It also investigates whether chondrocytes from the different zones respond distinctly to changes in the physical and mechanical microenvironment using three-dimensional porous scaffolds by changing stiffness and pore size. Cartilage was harvested from patients with end-stage varus knee OA. Cartilage from the lesion and remote zones were compared through histological and biomechanical assessments, and through proteomic and gene transcription analyses of chondrocytes. Gelatin scaffolds with varied pore sizes and stiffness were used to investigate in vitro microenvironmental regulation of chondrocytes from the two zones. Cartilage from the lesion and remote zones differed significantly (p < 0.05) in histological and biomechanical characteristics, as well as phenotype, protein, and gene expression of chondrocytes. Chondrocytes from both zones were sensitive to changes in the structural and mechanical properties of gelatin scaffolds. Of interest, although all chondrocytes better retained chondrocyte phenotype in stiffer scaffolds, those from the lesion and remote zones, respectively, preferred scaffolds with larger and smaller pores. Distinct variations exist in cartilage and chondrocyte characteristics in the lesion and remote zones of knee OA. Cells in these two zones respond differently to variations in the physical and mechanical microenvironment. Understanding and manipulating these differences will facilitate the development of more efficient and precise diagnostic and therapeutic approaches for knee OA.

Direct incorporation of mesenchymal stem cells into a Nanofiber scaffold \u2013 in vitro and in vivo analysis

Bony defects are a common problem in musculoskeletal surgery. Replacement with autologous bone grafts is limited by availability of transplant material. Sterilized cancellous bone, while being osteoconductive, has limited osteoinductivity. Nanofiber scaffolds are currently used for several purposes due to their capability of imitating the extracellular matrix. Furthermore, they allow modification to provide functional properties. Previously we showed that electrospun nanofiber scaffolds can be used for bone tissue regeneration. While aiming to use the osteoinductive capacities of collagen type-I nanofibers we saw reduced scaffold pore sizes that limited cellular migration and thus colonization of the scaffolds. Aim of the present study was the incorporation of mesenchymal stem cells into the electrospinning process of a nanofiber scaffold to produce cell-seeded nanofiber scaffolds for bone replacement. After construction of a suitable spinning apparatus for simultaneous electrospinning and spraying with independently controllable spinning and spraying devices and extensive optimization of the spinning process, in vitro and in vivo evaluation of the resulting scaffolds was conducted. Stem cells isolated from rat femora were incorporated into PLLA (poly-l-lactide acid) and PLLA-collagen type-I nanofiber scaffolds (PLLA Col I Blend) via simultaneous electrospinning and –spraying. Metabolic activity, proliferation and osteoblastic differentiation were assessed in vitro. For in vivo evaluation scaffolds were implanted into critical size defects of the rat scull. After 4 weeks, animals were sacrificed and bone healing was analyzed using CT-scans, histological, immunhistochemical and fluorescence evaluation. Successful integration of mesenchymal stem cells into the scaffolds was achieved by iteration of spinning and spraying conditions regarding polymer solvent, spinning distance, the use of a liquid counter-electrode, electrode voltage and spinning duration. In vivo formation of bone tissue was achieved. Using a PLLA scaffold, comparable results for the cell-free and cell-seeded scaffolds were found, while the cell-seeded PLLA-collagen scaffolds showed significantly better bone formation when compared to the cell-free PLLA-collagen scaffolds. These results provide support for the future use of cell-seeded nanofiber scaffolds for large bony defects.

Porous Architecture Evaluation of Silk Fibroin Scaffold from Direct Dissolution Salt Leaching Method

AbstractTissue engineering scaffold is used to facilitate and support cell/tissue growth. Fabrication of silk fibroin scaffold using newly developed direct dissolution salt leaching method is successfully done. This method significantly reduces the processing time compared to the traditional method. Cells attachment, cells growth, cells migration, and diffusion of nutrients and waste are affected by the architecture scaffold. In this study, 3D analysis on porous architecture evaluation of direct dissolution salt leaching scaffolds is conducted. Scaffolds are fabricated from different NaCl particle sizes of 158, 250, 378, and 503 μm at 12% w/v silk fibroin concentration. Scaffold architecture is evaluated using microcomputed tomography (micro‐CT) method. Evaluation of scaffold architecture shows that the use of larger NaCl particle size increases the scaffold pore size. The relationship between scaffold pore size and scaffold porosity, scaffold wall thickness, pore interconnectivity, scaffold specific surface area is established, which is important for tissue formation.

Honey loaded silk fibroin 3D porous scaffold facilitates homeostatic full-thickness wound healing

Dermal reconstruction in acute and chronic wounds needs highly vascularized dermal tissue engineered skin substitutes which has the potentiality to provide physical cues as well as biological cues for scarless regenerative wound healing. Herein, we have investigated blends of silk fibroin and honey as a wound healing substrate that able to facilitate keratinocyte and fibroblast adhesion, migration and proliferation. Honey-silk fibroin (HSF) three dimensional (3D) scaffolds were fabricated by freeze drying and characterized in detailed for their physico-chemical, mechanical, swelling and degradable properties. Interestingly, in vitro studies showed better adhesion, proliferation and homogenous distribution of fibroblasts within blended scaffolds especially with 4% honey concentration (HSF4). Also, its structural composition with pores size ~ 139 µm and porosity 87% further confirms the superiority over the counterparts and other blended scaffolds. The in vitro cytotoxic studies illustrated the biocompatibility, proliferation and proper infiltration of primary fibroblasts within HSF4 scaffolds, validated by in vivo studies. Fascinatingly, in vivo cutaneous wound healing studies demonstrated the attainment of normal homeostasis with proper re-epithelialization, collagen matrix remodeling having high collagen I expression in respect to collagen III with minimal scar under HSF4 scaffold implantation. Taken together, this study suggests the potentiality of incorporation of honey component as a payload which not only augmented the scarless healing also modified the physical properties of scaffold in order to provide the suitable micro-ambience for healing and these material scaffold proved to be a potential dermal substitute for acute as well as chronic wounds. Statement of SignificanceThe 3D honey based porous scaffolds are increasingly getting attention in the field of biomedicine and wound healing due to their ability to mimic the architecture of native microenvironment and could provide the controlled release of honey at the affected area for fast regeneration. In this work we demonstrated that the addition of honey in SF scaffold not only enhanced the biological activity of scaffold also modulated the physico-chemical properties which ultimately helps in attaining fast homeostatic wound healing. The synergy of pore size, porosity and mechanical strength of scaffold having 4% honey concentration showed its potentiality in augmenting proper re-epithelialization, collagen matrix deposition and skin appendages formation which presents this scaffold as potential candidate in skin tissue engineering applications.

Physico-chemical and biological properties of electrospun poly-L-lactic acid/hydroxyapatite nano-composite scaffold for bone regeneration

The main goal of tissue engineering is to design scaffolds with the suitable microenvironment, prominent mechanical properties, adequate biocompatibility, and biodegradability. In the present study, Poly-L-lactic acid (PLLA)/10% hydroxyapatite (HA) nano-composite (PLLA/HA) scaffold and pure PLLA scaffold were fabricated via electrospinning technique. They were then assessed for their potential as substrates for the cell culture. The scaffolds were characterized by scanning electron microscope, thermogravimetric analysis, differential thermal analysis, and fourier transform infrared spectroscopy. The results showed the dispersion and integration of HA nanoparticles in the composite scaffold. Pore size distribution measurements indicated that the scaffold pore size in terms of Ferret diameter varies between 0.1 and 22.0 µm. In vitro degradation behavior of the scaffold in phosphate buffered saline (PBS) was obtained by measuring water uptake, weight loss, and pH change of the PBS during the degradation period. We observed that the degradation of the scaffold could be markedly accelerated by HA nanoparticle (10%). It was also shown that acidification of the PBS due to the PLLA degradation is suppressed by the HA nanoparticles. Finally, human umbilical-cord-derived mesenchymal stem cells (hUC-MSCs) were used to evaluate the cellular support of the composite scaffolds. The presence of HA nanoparticles in the PLLA fibrous scaffolds resulted in promoting the attachment and the proliferation of the hUC-MSCs. This study suggests that the PLLA/HA scaffold could be the material of choice for functional bone tissue engineering.

The Dielectric Characterization of Tapioca Starch – Ha Tissue Scaffold

Tapioca starch-hydroxyapatite (HA) composites scaffold was fabricated using solvent casting and particulate leaching. The solvent casting involved the casting of polymer while particulate leaching involved the removal of porogen agent. The percentage of tapioca starch used were 50%, 60%, 70%, 80% and 90%, with the percentages of hydroxyapatite (HA) were set as 50%, 40%, 30%, 20% and 10% respectively. Here, sodium chloride was used as a porogen agent. SEM analysis was conducted to determine the micro structural of the scaffold surface. Based on the results, the pore size of composite scaffold is between ranges of 198 µm to 786 µm. For the dielectric study, the dielectric constants (D’) and dielectric loss factor (D”) over frequency range from 12.4 GHz to 18.0 GHz were obtained by transmission line method. Based on the result, both dielectric constant (s’) and dielectric loss factor (s”) was declined with the increment of the frequency.