Journal of Biomimetics, Biomaterials and Biomedical Engineering Vol. 60

Abstract: The main purpose of this study is to synthesize nano-hydroxyapatite/cellulose (nHAP/Cel) and nano-hydroxyapatite/chitosan (nHAP/CS) scaffolds via co-precipitation method for bone tissue engineering due to their suitable biocompatibility, cytotoxicity and mechanical properties. The characterizations of these scaffolds were investigated by Infrared absorption spectra (FT-IR), X-ray Diffraction (XRD), and Scanning Electron Microscope (SEM). The cytotoxicity of these nanoparticles was evaluated with bone marrow cell using the 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazoliumbromide) (MTT) assay. The porosity of scaffolds was estimated 87%. The results indicate that the nano composite scaffolds have good morphology, tissue biocompatibility and biodegradability to be used for tissue engineering.

Abstract: Collagen has been widely used in biomedical applications, mainly to develop structures (cell scaffolds) that allow cell growth and differentiation processes. This biomolecule is also used in cosmetics because it is an essential ingredient of certain makeup and in pharmaceutics for bandages to treat wounds and burns. However, the use of collagen has been limited by the ethical and moral implications of the (typically animal) sources from which it is extracted. Therefore, alternative, more environmentally friendly sources should be found to obtain collagen. Extracting collagen from fishing industry waste (such as scales, bones, and fish skin) has been presented as an advantageous alternative to obtain this biomaterial, which has also shown promising results due to its biocompatibility with human structures (organs and tissues). The characteristics of this molecule and other sources from which it can be obtained should be further studied.

Abstract: Zeolitic imidazolate frameworks-8 (ZIF-8), a type of metal-organic frameworks (MOFs), displays high porosity, large surface areas, and tunable functionality in nanocomposites, promising carrier for drug delivery applications. In this work, ZIF-8 nanomaterials were synthesized via precipitation under three different conditions and subsequently loaded onto chitosan/pluronic F-127 (CS/PL) hydrogels. The ZIF-8 materials prepared in NH₄OH solution (ZIF-8-NH₄OH) showed a regular cubic shape with a large particle size of approximately 963 nm due to the acceleration of crystal growth in a basic medium. Meanwhile, the ZIF-8 species prepared in H₂O and MeOH (ZIF-8-H₂O and ZIF-8-MeOH, respectively) displayed crystal sizes of approximately 152 and 240 nm, respectively. The overall toxicity of the ZIF-8 nanomaterials was determined with an XTT assay against the L929 mouse fibroblast cell line. The morphology of the cells was altered at a concentration of over 30 µg/mL due to cell membrane deformations. This result correlated with the lactate dehydrogenase (LDH) release study by detection of LDH release at a concentration of over 25 µg/mL (50% LDH release). To reduce the toxicity of the ZIF-8 materials, CS/PL hydrogels were appropriately prepared and used to encapsulate the ZIF-8 at 0.095% w/w. Cytotoxicity results of the ZIF-8-loaded CS/PL hydrogels indicated over 75% cell viability of the L929 cells. These results presented significant implications for future applications of the ZIF-8 particles in the delivery of drugs or other compounds.

Abstract: The aim of this study was to develop and characterize a delivery system for polyphenols from an extract of Carissa spinarum leaves, based on liposomes. Liposomes loaded with Carissa spinarum polyphenols (nanoliposomal CsP) were prepared by ethanol-solvent injection method and characterized in terms of zeta potential, size, and polydipersity index by using Zeta sizer and Fourier Transform Infrared spectrum analysis. Total Phenolic content was measured by using Folin-Ciocalteu method and entrapment efficiency was evaluated. The release behavior was conducted in Phosphate Buffer Saline (PBS) solution at pH, 7.4 and Kinetic model fitted to evaluate mechanism of release. Disc diffusion sensitivity test was used to evaluate antimicrobial activity of free extract and nanoliposomal CsP. The mean diameter of nanoliposomal CsP was 181 ± 1.02 nm and had 0.345 ± 0.014 polydipersity index. Zeta potential value for nanoliposomal CsP was-45.6 ± 8.84 mV. Entrapment efficiency under the optimum conditions was 66.11 ± 1.11%. and the nanoliposomal CsP was stable over 30 days. The antibacterial activity of nanoliposomal CsP exhibited inhibition zone diameter of 14.33 ± 1.53 mm and 12.00 ± 1.23 mm against S. aureus and E. coli respectively The results reveal the Carrisa spinarum liposome can be applied as potential carrier for delivery of polyphenols to improves therapeutic action against bacterial strain.

Abstract: The aim of the present investigation is to determine the ideal values for several parameters, such as the external diameter of the polyethylene liner, the Young's modulus of the cup, and the friction coefficients between the polyethylene liner's contact area and the acetabular shell and prosthetic head of the dual-mobility cup. Reduced stresses at the bone/cement interface are crucial for ensuring a well-fixed dual-mobility cup (DMC) with the acetabulum because orthopedic cement (PMMA) is the weakest component of total hip arthroplasty (THA). Four factors, such as the PE liner size, the rigidity of the cup, and the friction coefficients, are optimized using the three-dimensional finite element method (FEM) and experimental design approach (EDA). The numerical results show that the hemispherical-liner size, mechanical characteristics of the cup, surface state of the femoral head, liner PE, and shell components all influence the mechanical strength of the bone cement. To prevent fracturing the bone cement, which would render the total hip arthroplasty ineffective. The optimal values of the maximum von Mises stress in bone cement will be determined using this methodology. The numerical outcome shows that when the Young's modulus of the cup rises, the maximum stress in bone cement falls until it reaches a minimal value. The maximum stress in bone cement, however, increases as the PE liner's exterior diameter increases. Because the maximum stress is still below the yield stress of bone cement, the artificial hip joint is still considered safe despite the increased stress value.

Abstract: The cervical spine is a complex anatomical structure that mainly stabilizes the head and protects the spinal cord. Injuries of the cervical spine often occur during falls or road accidents and are particularly serious since they generate strong threats of paralysis and death. It should be noted that the ligaments provide cervical stability but their stabilization in case of injury is not yet well investigated. In this context, the objective of the present work is to study the failure of the ligaments by developing a bio-faithful numerical model while using a more realistic geometry of the spinal components and behavior laws that take into account the effect of strain rate and motion amplitudes. In order to validate the results of the study, we conducted a comparison with previous literature studies. It has been found that damage is often supported by intervertebral discs, anterior longitudinal ligaments (ALL) and capsular ligaments (CL) in the case of frontal impact. Indeed, the highest stresses are concentrated in the annulus fibrosus and the capsular ligaments. In this study, we tested the effect of ligament tears on disc behavior, where it was found that the stress rate increased by approximately 6%. The effect of capsular ligament tear orientation was also examined. The obtained results show that the most dangerous inclination was downward at an angle of 45°.

Abstract: The relationship between implant thread design and dental bone arguably has an influence on the distribution of bone stresses. However, the existing data on the influence of the thread profiles on bone stresses is considerably conflicting. For example, some studies concluded that thread shape has a substantial effect on the intensity of bone stresses, while others revealed that thread shape has no effect on the intensity of bone stresses. Accordingly, this study aims to computationally investigate and compare the effect of dental implant thread design on bone stresses under axial loading using a finite element analysis (FEA) approach. A geometrical model of V-thread and square thread implants, with a fixed thread pitch of 0.8 mm and a depth of 42 mm, and the surrounding bone was developed to assess the stresses generated within the implant components and bone structure under a 114 N axial load. The simulation is primarily concerned with the von Mises stresses within the implant components and the surrounding bone. The results demonstrate that the V-thread implant causes extremely high stress on the cortical and cancellous bones compared to the square thread implant. For example, the maximum stresses induced in the cortical bone are 195.3 MPa and 68.8 MPa, while the maximum stresses created in the cancellous bone are 19.7 Mpa and 2.2 Mpa in both designs, respectively. In addition, the cortical bone stresses substantially exceed the implant body stresses in both designs, with maximum stresses of 93.18 Mpa and 41 Mpa for V-thread and square-thread implants, respectively. However, the implant thread shape doesn’t affect the stress distribution in the abutment and screw. In general, the results show that implant thread design can result in featured mechanical stresses in the implant body and bone structure.

Abstract: Many studies have studied the relationships between handgrip strength and different Anthropometric variables. However, the hand anatomical position when measuring the handgrip strength was not clear in many studies. This study aims to investigate the relationship between the anthropometric measurements and the handgrip strength at different anatomical positions of the arm among young individuals. 59 young males and 41 females were asked to squeeze the hand dynamometer to their maximum capacity. The maximum handgrip force was recorded for 7 different arm anatomical positions. Using SPSS, an Independent student's t-test was used to compare male and female groups. Pearson’s correlation coefficients were used to determine the correlations between handgrip strength and the anthropometric measurements, weight, and BMI at different arm anatomical positions. Furthermore, the dominance weight was computed to determine the most important predictors of grip strength. Significant correlation between handgrip strength and height and weight at all positions and with hand length for all positions except when the arm was abducted and extended 180 ͦ at the shoulder joint and 180 ͦ at the elbow joint. Arm length, forearm length and handbreadth were also correlated to handgrip strength at three positions, when the arm was adducted with 90 ͦ forward at the elbow joint, when the Arm was abducted with 90 ͦ at the shoulder joint and 180 ͦ at the elbow, and when the arm was abducted with 90 ͦ at the shoulder joint and 90 ͦ at the elbow joint with the forearm perpendicular to the frontal plane. However, these correlations were different when males and females were considered separately. Furthermore, the results showed that the height followed by hand length had the highest prediction power of handgrip strength among young adults. The current results showed the importance of considering the different anatomical positions of the arm when studying the relationship between anthropometric measurements and hand grip strength.

Abstract: A new method for premature ventricular contraction (PVC) detection and classification is presented. The proposed algorithm is constituted of two principal phases: the features extraction and reduction phase and the optimized classification phase. In the first phase, the discrete cosine transform (DCT) and the continuous wavelet transform (CWT) are applied on each ECG beat to generate an augmented features vector. For the optimized classification phase, the radial basis function (RBF) neural network classifier is trained and optimized by the bat algorithm. For the aim of performances evaluation of the proposed method, the MIT-BIH arrhythmia database has been used. Consequently, the BAT-RBF classifier yielded an overall sensitivity of 95,2% and an accuracy of 98,2%, confirming clearly the competitiveness of the proposed method compared to some recent and powerful algorithms.

Abstract: Automatic sleep scoring systems have being much more attention in last decades. Whereas a wide variety of studies have been used in this subject area, the accuracies are still under acceptable limits to apply these methods in real life data. One can find many high accuracy studies in literature using standard database but when it comes to the using real data reaching such a high performances is not straightforward. In this study, five distinct datasets were prepared using 124 persons including 93 unhealthy and 31 healthy persons. These datasets consist of time-, nonlinear-, welch-, discrete wavelet transform-and Hilbert-Huang transform-features. By applying k-NN, Decision Trees, ANN, SVM and Bagged Tree classifiers to these feature sets in various manners by using feature-selection highest classification accuracy was searched. The maximum classification accuracy was detected in case of Bagged Tree classifier as 95.06% with the use of 14 features among a total of 136 features. This accuracy is relatively high compared with literature for a real-data application.