A comparison of several separation processes for eggshell membrane powder as a natural biomaterial for skin regeneration.

BACKGROUND: Numerous studies have focused on skin damage, the most prevalent physical injury, aiming to improve wound healing. The exploration of biomaterials, specifically eggshell membranes (ESMs), is undertaken to accelerate the recovery of skin injuries. The membrane must be separated from the shell to make this biomaterial usable. Hence, this investigation aimed to identify more about the methods for membrane isolation and determine the most efficient one for usage as a biomaterial. METHODS AND MATERIALS: For this purpose, ESM was removed from eggs using different protocols (with sodium carbonate, acetic acid, HCl, calcium carbonate, and using forceps for separation). Consequently, we have examined the membranes' mechanical and morphological qualities. RESULTS: According to the analysis of microscopic surface morphology, the membranes have appropriate porosity. MTT assay also revealed that the membranes have no cytotoxic effect on 3T3 cells. The results indicated that the ESM had acquired acceptable coagulation and was compatible with blood. Based on the obtained results, Provacol 4 (0.5-mol HCl and neutralized with 0.1-mol NaOH) was better than other methods of extraction and eggshell separation because it was more cell-compatible and more compatible with blood. CONCLUSION: This study demonstrates that ESMs can be used as a suitable biomaterial in medical applications.

Hydrogel-Based Skin Regeneration.

The skin is subject to damage from the surrounding environment. The repair of skin wounds can be very challenging due to several factors such as severe injuries, concomitant infections, or comorbidities such as diabetes. Different drugs and wound dressings have been used to treat skin wounds. Tissue engineering, a novel therapeutic approach, revolutionized the treatment and regeneration of challenging tissue damage. This field includes the use of synthetic and natural biomaterials that support the growth of tissues or organs outside the body. Accordingly, the demand for polymer-based therapeutic strategies for skin tissue defects is significantly increasing. Among the various 3D scaffolds used in tissue engineering, hydrogel scaffolds have gained special significance due to their unique properties such as natural mimicry of the extracellular matrix (ECM), moisture retention, porosity, biocompatibility, biodegradability, and biocompatibility properties. First, this article delineates the process of wound healing and conventional methods of treating wounds. It then presents an examination of the structure and manufacturing methods of hydrogels, followed by an analysis of their crucial characteristics in healing skin wounds and the most recent advancements in using hydrogel dressings for this purpose. Finally, it discusses the potential future advancements in hydrogel materials within the realm of wound healing.

Nanofibrous polycaprolactone/gelatin scaffold containing gold nanoparticles: Physicochemical and biological characterization for wound healing.

In this study, gold nanoparticles were loaded into poly (ε-caprolactone) (PCL)/gelatin nanofibrous matrices to fabricate a potential wound dressing. The mats were produced by electrospinning of PCL/gelatin solution supplemented with synthesized gold nanoparticles (200, 400 and 800 ppm). Prepared scaffolds were investigated regarding their chemical properties, morphology, mechanical properties, surface wettability, water-uptake capacity, water vapor permeability, porosity, blood compatibility, microbial penetration test and cellular response. In addition to in vivo study, a full-thickness excisional wound in a rat model was used to evaluate the healing effect of prepared scaffolds. Results showed appropriate mechanical properties and porosity of prepared scaffolds. With L929 cells, the PCL/gelatin scaffold containing 400 ppm gold nanoparticles demonstrated the greatest cell growth. In vivo results validated the favorable wound-healing benefits of the scaffold incorporating gold nanoparticles, which triggered wound healing compared to sterile gauze. Our results showed the capability of nanofibrous matrices containing gold nanoparticles for successful wound treatment.

Bone regeneration in rat using polycaprolactone/gelatin/epinephrine scaffold.

Solid supports like the extracellular matrix network are necessary for bone cell attachment and start healing in the damaged bone. Scaffolds which are made of different materials are widely used as a supportive structure in bone tissue engineering. In the current study, a 3D polycaprolactone/gelatin bone scaffold was developed by blending electrospinning and freeze-drying techniques for bone tissue engineering. To improve the efficiency of the scaffold, different concentrations of epinephrine (EP) due to its effect on bone healing were loaded. Fabricated scaffolds were characterized by different tests such as surface morphology, FTIR, porosity, compressive strength, water contact angle, and degradation rate. The interaction between prepared scaffolds and blood and cells was evaluated by hemolysis, and MTT test, respectively, and bone healing was evaluated by a rat calvaria defect model. Based on the results, the porosity of scaffolds was about 75% and by adding EP, mechanical strength decreased while due to the hydrophilic properties of it, degradation rate increased. In vivo and in vitro studies showed the best cell proliferation and bone healing were in PCL/gelatin/EP1% treated group. These results showed the positive effect of fabricated scaffold on osteogenesis and bone healing and the possibility of using it in clinical trials.

Kaolin-loaded chitosan/polyvinyl alcohol electrospun scaffold as a wound dressing material: in vitro and in vivo studies.

OBJECTIVE: To evaluate the application of a fabricated dressing containing kaolin for skin regeneration in a rat model of excisional wounds. METHOD: In the present study, kaolin was loaded into electrospun polyvinyl alcohol (PVA)/chitosan polymer blend to develop a composite nanofibrous dressing. To make the yarns, kaolin with weight ratio of 5% was added to PVA/chitosan polymer blend and subsequently formed into nanofibres using the electrospinning method. Scaffolds were evaluated for to their microstructure, mechanical properties, surface wettability, water vapour transmission rate, water-uptake capacity, blood uptake capacity, blood compatibility, microbial penetration test, the number of colonies, and cellular response with the L929 cell line. Rats with full-thickness excisional wounds were treated with kaolin-containing and kaolin-free dressings. RESULTS: The study showed that rats treated with the kaolin-incorporated mats demonstrated a significant closure to nearly 97.62±4.81% after 14 days compared with PVA/chitosan and the sterile gauze, which showed 86.15±8.11% and 78.50±4.22% of wound closure, respectively. The histopathological studies showed that in the PVA/chitosan/kaolin group, dense and regular collagen fibres were formed, while wounds treated with sterile gauze or PVA/chitosan scaffolds had random and loose collagen fibres. CONCLUSION: Our results show the potential applicability of PVA/chitosan/kaolin scaffolds as a wound care material.

Fabrication of Poly(L-Lactic Acid)/Chitosan Scaffolds by Solid-Liquid Phase Separation Method for Nerve Tissue Engineering: An In Vitro Study on Human Neuroblasts.

Polymeric scaffolds that support neural cell behaviors are attracting more attention. In the present study, solid-liquid phase separation technique is used to fabricate scaffolds made of poly(L-lactic acid) (PLLA) and chitosan (CS) blends to mimic both cellular microenvironment and anatomical structure of nerve tissue. The fabricated scaffolds favor characteristics of both natural and synthetic polymers. Different tests and assays including physical and mechanical ones (in vitro degradation rate, free radical release, hydrophilicity, and porosity measurements, microstructure observation, and mechanical tests) and cellular assays (cell attachment measurement and viability assessment) suggest that blend scaffolds prepared with this method support nerve cells for tissue engineering applications adequately and even better than scaffolds prepared with the same method but from pure PLLA or CS.

Polyurethane/Gelatin Nanofibrils Neural Guidance Conduit Containing Platelet-Rich Plasma and Melatonin for Transplantation of Schwann Cells.

The current study aimed to enhance the efficacy of peripheral nerve regeneration using a biodegradable porous neural guidance conduit as a carrier to transplant allogeneic Schwann cells (SCs). The conduit was prepared from polyurethane (PU) and gelatin nanofibrils (GNFs) using thermally induced phase separation technique and filled with melatonin (MLT) and platelet-rich plasma (PRP). The prepared conduit had the porosity of 87.17 ± 1.89%, the contact angle of 78.17 ± 5.30° and the ultimate tensile strength and Young's modulus of 5.40 ± 0.98 MPa and 3.13 ± 0.65 GPa, respectively. The conduit lost about 14% of its weight after 60 days in distilled water. The produced conduit enhanced the proliferation of SCs demonstrated by a tetrazolium salt-based assay. For functional analysis, the conduit was seeded with 1.50 × 104 SCs (PU/GNFs/PRP/MLT/SCs) and implanted into a 10-mm sciatic nerve defect of Wistar rat. Three control groups were used: (1) PU/GNFs/SCs, (2) PU/GNFs/PRP/SCs, and (3) Autograft. The results of sciatic functional index, hot plate latency, compound muscle action potential amplitude and latency, weight-loss percentage of wet gastrocnemius muscle and histopathological examination using hematoxylin-eosin and Luxol fast blue staining, demonstrated that using the PU/GNFs/PRP/MLT conduit to transplant SCs to the sciatic nerve defect resulted in a higher regenerative outcome than the PU/GNFs and PU/GNFs/PRP conduits.

In vitro and in vivo investigation of PLA/PCL scaffold coated with metformin-loaded gelatin nanocarriers in regeneration of critical-sized bone defects.

Large bone defects constitute a major challenge in bone tissue engineering and usually fail to heal due to the incomplete differentiation of recruited mesenchymal stem cells (MSCs) into osteogenic precursor cells. As previously proposed, metformin (MET) induces differentiation of MSCs into osteoblastic lineages in vitro. We fabricated a Poly (lactic acid) and Polycaprolactone (PLA/PCL) scaffold to deliver metformin loaded gelatin nanocarriers (MET/GNs) to critical-sized calvarial bone defects in a rat model. The scaffolds were evaluated regarding their morphology, porosity, contact angle, degradation rate, blood compatibility, biomechanical, cell viability and their osteogenic differentiation. In animal study, the defects were filled with autograft, scaffolds and a group was left empty. qRT-PCR analyses showed the expression level of osteogenic and angiogenic markers considerably increased in MET/GNs-PLA/PCL. The in vivo results showed that MET/GNs-PLA/PCL improved bone ingrowth, angiogenesis and defect reconstruction. Our results represent the applicability of MET/GNs-PLA/PCL for successful bone regeneration.

Magnesium-oxide-enhanced bone regeneration: 3D-printing of gelatin-coated composite scaffolds with sustained Rosuvastatin release.

Critical-size bone defects are one of the main challenges in bone tissue regeneration that determines the need to use angiogenic and osteogenic agents. Rosuvastatin (RSV) is a class of cholesterol-lowering drugs with osteogenic potential. Magnesium oxide (MgO) is an angiogenesis component affecting apatite formation. This study aims to evaluate 3D-printed Polycaprolactone/ß-tricalcium phosphate/nano-hydroxyapatite/ MgO (PCL/ß-TCP/nHA/MgO) scaffolds as a carrier for MgO and RSV in bone regeneration. For this purpose, PCL/ß-TCP/nHA/MgO scaffolds were fabricated with a 3D-printing method and coated with gelatin and RSV. The biocompatibility and osteogenicity of scaffolds were examined with MTT, ALP, and Alizarin red staining. Finally, the scaffolds were implanted in a bone defect of rat's calvaria, and tissue regeneration was investigated after 3 months. Our results showed that the simultaneous presence of RSV and MgO improved biocompatibility, wettability, degradation rate, and ALP activity but decreased mechanical strength. PCL/ß-TCP/nHA/MgO/gelatin-RSV scaffolds produced sustained release of MgO and RSV within 30 days. CT images showed that PCL/ß-TCP/nHA/MgO/gelatin-RSV scaffolds filled approximately 86.83 + 4.9 % of the defects within 3 months and improved angiogenesis, woven bone, and osteogenic genes expression. These results indicate the potential of PCL/ß-TCP/nHA/MgO/gelatin-RSV scaffolds as a promising tool for bone regeneration and clinical trials.

Therapeutic effect of 5-ASA and hesperidin-loaded chitosan/Eudragit® S100 nanoparticles as a pH-sensitive carrier for local targeted drug delivery in a rat model of ulcerative colitis.

Ulcerative colitis (UC) is an idiopathic disease characterized by colonic mucosal tissue destruction secondary to an excessive immune response. We synthesized pH-sensitive cross-linked chitosan/Eudragit® S100 nanoparticles (EU S100/CS NPs) as carriers for 5-aminosalicylic acid (5-ASA) and hesperidin (HSP), then conducted in-vitro and in-vivo studies and evaluated the therapeutic effects. In-vitro analysis revealed that the 5-ASA-loaded EU S100/CS NPs and the HSP-loaded EU S100/CS NPs had smooth and curved surfaces and ranged in size between 250 and 300 nm, with a zeta potential of 32 to 34 mV. FTIR analysis demonstrated that the drugs were loaded on the nanoparticles without significant alterations. The loading capacity and encapsulation efficiency of loading 5-ASA onto EU S100/CS NPs were 25.13 % and 60.81 %, respectively. Regarding HSP, these values were 38.34 % and 77.84 %, respectively. Drug release did not occur in simulated gastric fluid (SGF), while a slow-release pattern was recorded for both drugs in simulated intestinal fluid (SIF). In-vivo macroscopic and histopathological examinations revealed that both NPs containing drugs significantly relieved the symptoms of acetic acid (AA)-induced UC in Wistar rats. We conclude that the synthesized pH-sensitive 5-ASA/EU S100/CS NPs and HSP/EU S100/CS NPs offer promise in treating UC.

Fabrication and Characterization of Nanofibrous Poly (L-Lactic Acid)/Chitosan-Based Scaffold by Liquid-Liquid Phase Separation Technique for Nerve Tissue Engineering.

Fabrication method is one of the essential factors which directly affect on the properties of scaffold. Several techniques have been well established to fabricate nanofibrous scaffolds such as electrospinning. However, preparing a three-dimensional (3-D) interconnected macro-pore scaffold essential for transporting the cell metabolites and nutrients is difficult using the electrospinning method. The main aim of this study was developing a highly porous scaffold by poly (L-lactic acid) (PLLA)/chitosan blend using liquid-liquid phase separation (LLPS) technique, a fast and cost-benefit method, in order to use in nerve tissue engineering. In addition, the effect of different polymeric concentrations on morphology, mechanical properties, hydrophilicity, in vitro degradation rate and pH alteration of the scaffolds were evaluated. Moreover, cell attachment, cell viability and cell proliferation of scaffolds as candidates for nerve tissue engineering was investigated. PLLA/chitosan blend not only had desirable structural properties, porosity, hydrophilicity, mechanical properties, degradation rate and pH alteration but also provided a favorable environment for attachment, viability, and proliferation of human neuroblastoma cells, exhibiting significant potential for nerve tissue engineering applications. However, the polymeric concentration in blend fabrication had influence on both characteristics and cell responses. It concluded that PLLA/chitosan nanofibrous 3-D scaffold fabricated by LLPS method as a suitable candidate for nerve tissue engineering.

Naturally occurring biological macromolecules-based hydrogels: Potential biomaterials for peripheral nerve regeneration.

Despite the recent advances in the treatment strategies of peripheral nerve system defects, peripheral nerve injury (PNI) is still one of the most important health issues with increasing incidence worldwide. The most commonly used treatment approaches are allografts, xenografts, and autologous, which have some drawbacks, including complications, limited source of the donor tissue, tubular collapse, and scar tissue formation. In this context, regenerative medicine has been introduced as a powerful approach to improve the healing process and obtain acceptable functional recovery in the injury site using living cells, scaffold, and bioactive (macro-) molecules. Amongst them, scaffold as a three-dimensional (3D) support biomaterial, structurally bridged the gap or site of injury in order to provide physical and chemical cues to promote correct reinnervation and functional regeneration. Amongst different scaffolding biomaterials, naturally occurring biological macromolecules (more especially proteins and polysaccharides)-based hydrogels exhibited promising results due to their fascinating physicochemical, as well as physiologically relevant properties. This review highlights the recent progress in the development of natural hydrogels-based neural scaffolds. Furthermore, PNI healing process, current status, and challenges are also shortly discussed.

Sophisticated polycaprolactone/gelatin nanofibrous nerve guided conduit containing platelet-rich plasma and citicoline for peripheral nerve regeneration: In vitro and in vivo study.

Peripheral nerve injury (PNI) is a devastating condition that may result in loss of sensory function, motor function, or both. In the present study, we construct an electrospun nerve guide conduit (NGC) based on polycaprolactone (PCL) and gelatin filled with citicoline bearing platelet-rich plasma (PRP) gel as a treatment for PNI. The NGCs fabricated from PCL/Gel polymeric blend using the electrospinning technique. The characterizations demonstrated that the fabricated nanofibers were straight with the diameter of 708 ±â€¯476 nm, the water contact angle of 78.30 ±â€¯2.52°, the weight loss of 41.60 ±â€¯6.94% during 60 days, the tensile strength of 5.31 ±â€¯0.97 MPa, and the young's modulus of 3.47 ±â€¯0.10 GPa. The in vitro studies revealed that the PCL/Gel/PRP/Citi NGC was biocompatible and hemocompatible. The in vivo studies conducted on sciatic nerve injury in rats showed that the implantation of PCL/Gel/PRP/Citi NGC induced regeneration of nerve tissue, demonstrated with histopathological assessments. Moreover, the sciatic function index (SFI) value of -30.3 ±â€¯3.5 and hot plate latency time of 6.10 ±â€¯1.10 s revealed that the PCL/Gel/PRP/Citi NGCs recovered motor and sensory functions. Our findings implied that the fabricated NGC exhibited promising physicochemical and biological activates favorable for PNI treatment.

A tailored polylactic acid/polycaprolactone biodegradable and bioactive 3D porous scaffold containing gelatin nanofibers and Taurine for bone regeneration.

The focus of the current study was to develop a functional and bioactive scaffold through the combination of 3D polylactic acid (PLA)/polycaprolactone (PCL) with gelatin nanofibers (GNFs) and Taurine (Tau) for bone defect regeneration. GNFs were fabricated via electrospinning dispersed in PLA/PCL polymer solution, Tau with different concentrations was added, and the polymer solution converted into a 3D and porous scaffold via the thermally-induced phase separation technique. The characterization results showed that the scaffolds have interconnected pores with the porosity of up to 90%. Moreover, Tau increased the wettability and weight loss rate, while compromised the compressive strengths. The scaffolds were hemo- and cytocompatible and supported cell viability and proliferation. The in vivo studies showed that the defects treated with scaffolds filled with new bone. The computed tomography (CT) imaging and histopathological observation revealed that the PLA/PCL/Gel/Tau 10% provided the highest new bone formation, angiogenesis, and woven bone among the treatment groups. Our finding illustrated that the fabricated scaffold was able to regenerate bone within the defect and can be considered as the effective scaffold for bone tissue engineering application.

Alginate hydrogel containing hydrogen sulfide as the functional wound dressing material: In vitro and in vivo study.

Functional and bioactive wound dressing materials are revolutionary for wound care and healing applications. In this concept, we fabricated alginate hydrogel (Alg) containing H2S as the wound dressing materials and assessed the morphology, swelling, degradation, and release behavior, as well as the biocompatibility, cytocompatibility, and wound healing activity. The results depicted that the prepared hydrogels have a porous structure with the pore size in the range of 50 to 100 µm. Swelling and degradation studies showed that the hydrogel absorbed water about 179 ± 5% of initial dry weight during 96 h and loos about 80% of the initial dry weight after 7 days. The in vitro assessments illustrated that the optimum concentration of H2S was 0.5% and the higher concentration induced hemolysis and cell toxicity. The in vivo study revealed that the treatment by Alg/H2S 0.5% induced the highest wound closure percent with a value of 98 ± 1.22%. Moreover, the treatment by Alg/H2S 0.5% elicited the formation of sebaceous glands, hair follicles, and complete epithelization without any fibroplasia or inflammation, revealed by the histopathological observations. Accordingly, these results illustrated that the prepared Alg/H2S 0.5% could be applied as the functional and bioactive wound dressing materials.

Electrospun cellulose acetate/gelatin nanofibrous wound dressing containing berberine for diabetic foot ulcer healing: in vitro and in vivo studies.

Functional wound dressing with tailored physicochemical and biological properties is vital for diabetic foot ulcer (DFU) treatment. Our main objective in the current study was to fabricate Cellulose Acetate/Gelatin (CA/Gel) electrospun mat loaded with berberine (Beri) as the DFU-specific wound dressing. The wound healing efficacy of the fabricated dressings was evaluated in streptozotocin-induced diabetic rats. The results demonstrated an average nanofiber diameter of 502 ± 150 nm, and the tensile strength, contact angle, porosity, water vapor permeability and water uptake ratio of CA/Gel nanofibers were around 2.83 ± 0.08 MPa, 58.07 ± 2.35°, 78.17 ± 1.04%, 11.23 ± 1.05 mg/cm2/hr, and 12.78 ± 0.32%, respectively, while these values for CA/Gel/Beri nanofibers were 2.69 ± 0.05 MPa, 56.93 ± 1°, 76.17 ± 0.76%, 10.17 ± 0.21 mg/cm2/hr, and 14.37 ± 0.42%, respectively. The antibacterial evaluations demonstrated that the dressings exhibited potent antibacterial activity. The collagen density of 88.8 ± 6.7% and the angiogenesis score of 19.8 ± 3.8 obtained in the animal studies indicate a proper wound healing. These findings implied that the incorporation of berberine did not compromise the physical properties of dressing, while improving the biological activities. In conclusion, our results indicated that the prepared mat is a proper wound dressing for DFU management and treatment.

Design and characterization of biodegradable multi layered electrospun nanofibers for corneal tissue engineering applications.

Tissue engineering is one of the most promising areas for treatment of various ophthalmic diseases particularly for patients who suffer from limbal stem cell deficiency and this is due to the lack of existence of appropriate matrix for stem cell regeneration. The aim of this research project is to design and fabricate triple layered electrospun nanofibers as a suitable corneal tissue engineering scaffold and the objective is to investigate and perform various in vitro tests to find the most optimum and suitable scaffold for this purpose. Electrospun scaffolds were prepared in three layers. Poly(d, l-lactide-co-glycolide; PLGA, 50:50) nanofibers were electrospun as outer and inner layers of the scaffold and aligned type I collagen nanofibers were electrospun in the middle layer. Furthermore, the scaffolds were cross-linked by 1-ethyl-3-(3 dimethylaminopropyl) carbodiimide hydrochloride and glutaraldehyde. Structural, physical, and mechanical properties of scaffolds were investigated by using N2 adsorption/desorption isotherms, Fourier transform infrared spectroscopy, contact angle measurement, tensile test, degradation, shrinkage analysis, and scanning electron microscopy (SEM). In addition, capability to support cell attachment and viability were characterized by SEM, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, and 4',6-diamidino-2-phenylindole staining. According to the result of Brunauer-Emmett-Teller analysis, specific surface area of electrospun scaffold was about 23.7 m2 g-1 . Tensile tests on cross-linked scaffolds represented more suitable hydrophilicity and tensile behavior. In addition, degradation rate analysis indicated that noncross-linked scaffolds degraded faster than cross-linked one and cross-linking led to controlled shrinkage in the scaffold. The SEM analysis depicted nano-sized fibers in good shape. Also, the in vitro study represented an improved cell attachment and proliferation in the presence of human endometrial stem cells for both cross-linked and noncross-linked samples. The current study suggests the possibility of producing an appropriate substrate for successful cornea tissue engineering with a novel design.

In vitro and in vivo evaluation of electrospun cellulose acetate/gelatin/hydroxyapatite nanocomposite mats for wound dressing applications.

The present study aimed to evaluate the efficacy of cellulose acetate/gelatin/nanohydroxyapatite (CA/Gel/nHA) nanocomposite mats as the wound dressing. The dressings were prepared with electrospinning of CA/Gel solutions containing 12.5, 25 and 50 mg nHA. The dressings were evaluated regarding their water uptake capacity, morphology, tensile strength, water vapour transmission rate, wettability and cellular response with L929 cell line. The results showed that the concentration of nHA had a direct correlation with porosity, water contact angle, water uptake, water vapor transmission rate and proliferation. In vivo studies showed that all dressings had higher wound closure percent than the sterile gauze, as the control. The highest wound closure value was achieved in the CA/Gel +25 mg nHA group, which showed 93.5 ± 1.6%. The histological and the histomorphometric examinations of the wounds revealed that the CA/Gel +25 mg nHA dressing had the greatest collagen synthesis, re-epithelialization, neovascularization and also the best cosmetic appearance. Based on our finding, it could be concluded the applicability of electrospun nanofibrous CA/Gel/nHA dressings for successful wound treatment.

Mechanical, material, and biological study of a PCL/bioactive glass bone scaffold: Importance of viscoelasticity.

Microsphere sintering method was used to fabricate bone tissue engineering scaffolds made of polycaprolactone (PCL)/bioactive glass 58S5Z (58S modified with 5 wt% Zinc). First, the effect of PCL/58S5Z ratio on the mechanical properties (elastic modulus and yield strength) was investigated. It was found that samples with 5 wt% 58S5Z (named 5%BG) had the highest elastic modulus and yield strength among all samples, i.e., with 0, 5, 10, and 20 wt% bioactive glass. Then, considering the importance of viscoelastic properties of bone, the viscoelastic behavior of 0%BG (scaffold with only PCL) and 5%BG samples was determined by performing compressive stress relaxation test and subsequently a Generalized Maxwell model was developed. Findings indicated a similar amount and pattern of predicted storage and loss moduli and loss factor of the composite scaffolds to those of the bone. In the next step, the analysis of biological behavior of the scaffolds using MTT assay, DAPI and Alizarin red staining demonstrated that 5%BG scaffolds had higher in vitro cell viability and bone formation compared to 0%BG ones. Furthermore, in vivo study employing H&E staining of the scaffolds implanted in rats' calvarium for 50 days, confirmed the earlier findings and showed that 5%BG-filled defects had higher and more uniform bone formation compared to both 0%BG-filled and empty defects.

Can gray values derived from CT and cone beam CT estimate new bone formation? An in vivo study.

OBJECTIVES: The main aim of this study was to investigate whether Hounsfield unit derived from computed tomography (HU/CT) and gray value derived from cone beam computed tomography (GV/CBCT) can predict the amount of new bone formation (NBF) in the defects after bone reconstruction surgeries. MATERIALS AND METHODS: Thirty calvaria defects created in 5 rabbits and grafted with both radiolucent (RL, n = 15) and radiopaque (RO, n = 15) bone substitute materials were evaluated, 8 weeks postoperatively. The defects were scanned by multislice computed tomography (Somatom®, Siemens Healthineers, Erlangen, Germany) and CBCT (NewTom VG®, Qualitative Radiology, Verona, Italy). MSCT and CBCT scans were matched to select the exact region of interest (ROI, diameter = 5 mm and height = 1 mm). HU/CT and GV/CBCT of each ROI were obtained. Mean amount of NBF in whole of the defects was measured using serial histomorphometric assessment. We investigated the correlation between HU/CT and GV/CBCT, HU/CT and NBF, and GV/CBCT and NBF generally, and separately among the RL or RO grafted defects, by linear generalized estimating equation modeling. Receiver operation characteristic analysis was performed to check the accuracy of HU/CT and GV/CBCT in diagnosing more than 10% NBF in the samples. RESULTS: There were linear correlations between HU/CT and GV/CBCT, HU/CT and NBF, and GV/CBCT and NBF. CONCLUSION: According to the results, both HU/CT and GV/CBCT can be considered as fairly good predictors for assessment of the amount of NBF following bone reconstruction surgeries.