Journal of Biomimetics, Biomaterials and Biomedical Engineering Vol. 47

Abstract: The present study investigated the phase composition, the structural, morphological, and bioactivity properties of silicon- and carbonate-doped biomimetic hydroxyapatite synthesized by precipitation from aqueous solutions in the presence of different amounts of citrate ions. The X-ray diffraction and Fourier transform infrared spectroscopy analyses confirmed that all the samples exhibited single-phase. Base on the results of the morphological study, all the obtained samples consisted of porous agglomerated particles made up of tiny crystallites in the nanometer range. The change in structural order, as well as the decrease in particle size and degree of crystallinity result from the presence of citrate ions were revealed by X-ray diffraction, dynamic light scattering, and scanning electron microscopy analyses. Bioactivity properties of samples were studied by analyzing their bioresorbability in physiological saline (ω (NaCl) = 0.9%) and evaluating their solubility in SBF solution after a certain period of soaking time. The amount of the released Ca²⁺ ions was found to increase with the increasing concentration of citrate ions introduced in the synthesis process. The better solubility of material with the presence of citrate ions was beneficial in the growth of apatite on its surface that made produced material more biocompatible.

Abstract: Tooth loss due to periodontal disease, dental caries, trauma or a variety of genetic disorders causes an adverse inability in adult’s lives. It is proved that biodegradable composite scaffolds in dental tissue engineering could play crucial role. To inhibit bacterial colonization in dental structure noticeable research concerning the drug delivery approach has been administrated. Nanostructures retain and release drug molecules more efficiently and continuously than other microstructure. In the present research, composite electrospun nanofibers of polyurethane-Single-walled carbon nanotube (SWNT) by the different mass ratios of metronidazole benzoate were prepared. Physico-chemical characterization of scaffolds including Scanning electron microscopy (SEM), uniaxial tensile testing and Ultraviolet-Visible (UV-Vis) spectroscopy analysis was operated. Culture of dental pulp stem cells (DPSCs) to evaluate cells behavior was carried out. The role of nanofiber diameters and drug content on releasing profile of the scaffolds was investigated. The median diameter of the nanofibrous scaffold was reduced from 330 ± 4 to 120 ± 4 nm. Ultimate stress and Young modulus of the scaffolds by enhancement of drug content increased from 0.28 ± 0.05 up to the 1.8 ± 0.05 MPa and 0.87 ± 0.05 up to the 4.4 ± 0.05 Mpa respectively. According to the result, prolonged and continuous releasing profile of the drug molecules was achieved. As the content of the drug increased, the drug was released continuously. It means that two parameters of fiber's diameter and drug ratio affected the releasing behavior of composite structures. Polyurethane-SWNT scaffolds contained metronidazole benzoate presented appropriate support of DPSCs adhesion and proliferation and biomimetic architecture like the structure of dental ECM.

Abstract: Background: Hydroxyapatite (HAP), as a common biomaterial in bone tissue engineering, can be fabricated in combination with other osteogenic agents. Pentoxifylline (PTX) is demonstrated to have positive roles in bone defect healing. Since local administration can diminish the systemic side effects of the drug, the objectives of the current in vitro study were to find the effects of PTX on the osteoblast functions for tissue engineering applications. Methods: a HAP scaffold was fabricated by casting the HAP slurry within polyurethane foam. The scaffold was enriched with 5 mg/mL PTX. Alginate (Alg) was used as drug carrier to regulate the PTX releasing rate. MG-63 osteosarcoma cells were cultured on 3D scaffolds and 2D Alg films in the presence or absence of PTX. Results: PTX did not affect the cell viability, attachment and phenotype. Also, the ultrastructure of the scaffolds was not modified by PTX enrichment. Alizarin red S staining showed that PTX has no effect on calcium deposition. Besides, Raman confocal microscopy demonstrated an increase in the organic matrix formation including proline, valine and phenylalanine deposition (represented collagen). Although PTX increased the total protein secretion, it led to a decrease in the alkaline phosphatase activity and vascular endothelial growth factor (VEGF) content. PTX reduced the hydration and degradation rates and it was released mainly at the first 24 hours of incubation. Conclusion: Based on our in vitro study, application of engineered PTX-loaded HAP scaffold in bone regeneration can act on behalf of organic matrix production, but not angiogenesis and mineralization.

Abstract: Breast cancer occurs as a result of erratic growth and proliferation cells that originate in the breast. In this paper, the classifiers were used to identify the abnormalities on mammograms to get the region of interest (ROI). Before classifier based segmentation, noise, pectoral muscles, and tags were removed for a successful segmentation process. Then the proposed approach extracted the brightest regions using modified k-means. From the extracted brightest regions, shape and texture features were extracted and given to classifiers (KNN and SVM) and marked as ROI only those non-overlapping abnormal regions. The ROIs obtained using the proposed classifier-based segmentation algorithm was compared with the ground truth annotated by the radiologists. The datasets used to evaluate the performance of the proposed algorithm was public (MIAS) and local datasets (BGH and DADC).

Abstract: Electrospun fibers have demonstrated a remarkable potential as a framework structure in the fabrication of cartilage tissue engineering (CTE) scaffolds. Various extracellular matrices have been incorporated into electrospun scaffolds to mimic and simulate the extracellular environment. The objective of this study was to fabricate hybrid constructs using composite electrospun scaffolds based on poly (ε-caprolactone) (PCL) and cartilage-derived matrix (CDM) and fibrin hydrogel to improve the viability and differentiation of human adipose-derived stromal cells (ADSCs) for CTE applications.Initially, PCL and PCL-CDM electrospun mats were fabricated. Fibrin/ ADSCs hydrogel were seeded on PCL- CDM mats and arranged layer-by-layer using sandwich technique. This method has been employed to increase cell seeding and infiltration efficiency through the entire mass of the scaffold. Real-time reverse-transcription polymerase chain reaction (RT- PCR), were performed to examine the expression of collagen types II and X, SOX9 and aggrecan. The production of glycosaminoglycan (GAG) was also tested in vitro by Toluidine blue stain and biochemical assay in the cultured scaffolds.The findings demonstrated that incorporation of CDM in PCL fibers results in improved cell viability. Hematoxylin and eosin staining showed that the sandwich method resulted in homogenous cell seeding within the scaffold. Overall, the RT- PCR, biochemical and histological results, showed that incorporation of the CDM into PCL/fibrin sandwich scaffolds stimulated ADSCs chondrogenesis and produced the products which increased expression of chondrogenic genes. It also, enhanced GAG synthesis compared to PCL/fibrin scaffolds.These findings suggest PCL-CDM/fibrin can be considered as an appropriate hybrid scaffold for CTE applications.

Abstract: Medical segmentation is the primary task performed to diagnosis the abnormalities in the human body. The brain is the complex organ and anatomical segmentation of brain tissues is a challenging task. In this paper, we used Enhanced Independent component analysis to perform the segmentation of gray matter. We used modified K means, Expected Maximization and Hidden Markov random field to provide better spatial correlation that overcomes in-homogeneity, noise and low contrast. Our objective is achieved in two steps (i) initially unwanted tissues are clipped from the MRI image using skull stripped Algorithm (ii) Enhanced Independent Component analysis is used to perform the segmentation of gray matter. We apply the proposed method on both T1w and T2w MRI to perform segmentation of gray matter at different noisy environments. We evaluate the the performance of our proposed system with Jaccard Index, Dice Coefficient and Accuracy. We further compared the proposed system performance with the existing frameworks. Our proposed method gives better segmentation of gray matter useful for diagnosis neurodegenerative disorders.

Abstract: Many scientific data have proven that regular wearing of high-heeled shoes adversely affects human health. Recent evidence suggested that bionic heels imitated hoofed animals have attracted widespread attention. However, few biomechanical studies have investigated the effects of bionic high-heeled footwear on the lower limbs. Accordingly, this study aimed to examine the impact of bionic high-heeled shoes (HHS) on the biomechanical characteristics of lower limbs by comparing kinematics and kinetics of walking in HHS and bionic flat-bottomed shoes (FBS). they find that when the subjects wore HHS, the loading is concentrated in the forefoot region for a much longer time. Couple with HHS lacks the cushioning effect of the complete sole, the sole has to rely only on plantar flexion and dorsiflexion of the ankle joint to cushion the impact force, which will undoubtedly increase the fatigue damage of the ankle joint. The unique split-toe structure balances the loading between the toes could reduce the risk of toes injury during walking. However, there are still risks of injury to the lower limbs of HHS, especially the ankle and knee joints.

Abstract: Biomaterials can be used in several areas of regenerative bioengineering, and is a viable option in the repair of bone injuries. A number of different types of biomaterials have been studied in relation to bone repair. Ceramics such as α-TCP have low fracture toughness compared to natural bone, so reinforcements such as wollastonite whiskers are developed so that they can be used in places with greater overload. This study aimed to evaluate the biocompatibility and bone neoformation of α-TCP plus 10% wollastonite whiskers, in vivo. To obtain the cement, α-TCP powders with or without 10% wollastonite whiskers were added to an aqueous solution containing 2.5% by weight of Na2HPO4 (anhydrous bibasic sodium phosphate). The biomaterial then became a paste, which was molded into the critical 5 mm defect made in the parietal bone of Wistar rats. Ten rats were divided into two groups. The animals from each group were euthanized within 30 days. Calvaries were removed and subjected to histological processing with Eosin and Hematoxylin. The implementation of the whisker biomaterial revealed the formation of intensely vascularized connective tissue in the implemented region; however, animals with the biomaterial α-TCP showed the formation of this tissue around the implemented region. On the other hand, intense bone resorption was observed only in the animals with Wollastonite Whiskers, but new bone formation in both groups. The biomaterial evaluated was shown to be non-cytotoxic, resorbable, and capable of inducing bone neoformation; however, more studies should be carried out to assess the application of this biomaterial in bone injuries.

Abstract: Musculoskeletal disorders are the most common occupational diseases in Estonia and in the European Union as a whole. Sewing machine operators’ work is very monotonous, in continuous sitting position, with repetitive one-side movements of the upper limbs and legs. Working in an awkward posture and doing the same movements for a long period of time increases the risk of musculoskeletal system disorders, and in longer perspective, could cause work disability. The aim of the study was to analyse the prevalence of musculoskeletal disorders, intensity and duration of pain in a different body regions and to assess the changes of the functional status of the musculoskeletal system before and after the intervention among workers with partial work ability. The target group was 57 sewing machine operators, who were presented with an anonymous online questionnaire and agreed to participate in the intervention program. The study group was 12 sewing machine operators with partial work ability. RULA (Rapid Upper Limb Assessment) method was used for evaluating ergonomic workstations. The pain assessment was studied by NPRS, Numeric Pain Rating Scale. Online questionnaires were based on BQ (Baecke Physical Activity Questionnaire) and NMQ (The Nordic Musculoskeletal Questionnaire). The results showed that musculoskeletal status among workers with partial work ability improved after the intervention. Associations between individual and job related factors and musculoskeletal pain were observed. The research allows to make actual proposals for workplace layout of sewing machine operators, to provide ergonomic deployment and offer suitable exercise movements for rest breaks.