Showing papers by "Amin Hadi published in 2022"

In vitro static and dynamic cell culture study of novel bone scaffolds based on 3D-printed PLA and cell-laden alginate hydrogel

Abstract: The aim of this paper was to design and fabricate a novel composite scaffold based on the combination of 3D-printed polylactic acid-based triply periodic minimal surfaces (TPMSs) and cell-laden alginate hydrogel. This novel scaffold improves the low mechanical properties of alginate hydrogel and can also provide a scaffold with a suitable pore size, which can be used in bone regeneration applications. In this regard, an implicit function was used to generate some gyroid TPMS scaffolds. Then the fused deposition modeling process was employed to print the scaffolds. Moreover, the micro computed tomography technique was employed to assess the microstructure of 3D-printed TPMS scaffolds and obtain the real geometries of printed scaffolds. The mechanical properties of composite scaffolds were investigated under compression tests experimentally. It was shown that different mechanical behaviors could be obtained for different implicit function parameters. In this research, to assess the mechanical behavior of printed scaffolds in terms of the strain-stress curves on, two approaches were presented: equivalent volume and finite element-based volume. Results of strain-stress curves showed that the finite-element based approach predicts a higher level of stress. Moreover, the biological response of composite scaffolds in terms of cell viability, cell proliferation, and cell attachment was investigated. In this vein, a dynamic cell culture system was designed and fabricated, which improves mass transport through the composite scaffolds and applies mechanical loading to the cells, which helps cell proliferation. Moreover, the results of the novel composite scaffolds were compared to those without alginate, and it was shown that the composite scaffold could create more viability and cell proliferation in both dynamic and static cultures. Also, it was shown that scaffolds in dynamic cell culture have a better biological response than in static culture. In addition, scanning electron microscopy was employed to study the cell adhesion on the composite scaffolds, which showed excellent attachment between the scaffolds and cells.

In vitro static and dynamic cell culture study of novel bone scaffolds based on 3D-printed PLA and cell-laden alginate hydrogel

Abstract: The aim of this paper was to design and fabricate a novel composite scaffold based on the combination of 3D-printed polylactic acid-based triply periodic minimal surfaces (TPMSs) and cell-laden alginate hydrogel. This novel scaffold improves the low mechanical properties of alginate hydrogel and can also provide a scaffold with a suitable pore size, which can be used in bone regeneration applications. In this regard, an implicit function was used to generate some gyroid TPMS scaffolds. Then the fused deposition modeling process was employed to print the scaffolds. Moreover, the micro computed tomography technique was employed to assess the microstructure of 3D-printed TPMS scaffolds and obtain the real geometries of printed scaffolds. The mechanical properties of composite scaffolds were investigated under compression tests experimentally. It was shown that different mechanical behaviors could be obtained for different implicit function parameters. In this research, to assess the mechanical behavior of printed scaffolds in terms of the strain–stress curves on, two approaches were presented: equivalent volume and finite element-based volume. Results of strain–stress curves showed that the finite-element based approach predicts a higher level of stress. Moreover, the biological response of composite scaffolds in terms of cell viability, cell proliferation, and cell attachment was investigated. In this vein, a dynamic cell culture system was designed and fabricated, which improves mass transport through the composite scaffolds and applies mechanical loading to the cells, which helps cell proliferation. Moreover, the results of the novel composite scaffolds were compared to those without alginate, and it was shown that the composite scaffold could create more viability and cell proliferation in both dynamic and static cultures. Also, it was shown that scaffolds in dynamic cell culture have a better biological response than in static culture. In addition, scanning electron microscopy was employed to study the cell adhesion on the composite scaffolds, which showed excellent attachment between the scaffolds and cells.

Additively Manufactured Multi-Morphology Bone-like Porous Scaffolds: Experiments and Micro-Computed Tomography-Based Finite Element Modeling Approaches

Abstract: Tissue engineering, whose aim is to repair or replace damaged tissues by combining the principle of biomaterials and cell transplantation, is one of the most important and interdisciplinary fields of regenerative medicine. Despite remarkable progress, there are still some limitations in the tissue engineering field, among which designing and manufacturing suitable scaffolds. With the advent of additive manufacturing (AM), a breakthrough happened in the production of complex geometries. In this vein, AM has enhanced the field of bioprinting in generating biomimicking organs or artificial tissues possessing the required porous graded structure. In this study, triply periodic minimal surface structures, suitable to manufacture scaffolds mimicking bone’s heterogeneous nature, have been studied experimentally and numerically; the influence of the printing direction and printing material has been investigated. Various multi-morphology scaffolds, including gyroid, diamond, and I-graph and wrapped package graph (I-WP), with different transitional zone, have been three-dimensional (3D) printed and tested under compression. Further, a micro-computed tomography (μCT) analysis has been employed to obtain the real geometry of printed scaffolds. Finite element analyses have been also performed and compared with experimental results. Finally, the scaffolds’ behavior under complex loading has been investigated based on the combination of μCT and finite element modeling.

A review of applications of surface-enhanced raman spectroscopy laser for detection of biomaterials and a quick glance into its advances for COVID-19 investigations

Abstract: Surface-enhanced Raman spectroscopy (SERS) is one of the most sensitive analytical tools. In some cases, it is possible to record a high-quality SERS spectrum in which even a single molecule is involved. Therefore, SERS is considered a significantly promising option as an alternative to routine analytical techniques used in food, environmental, biochemical, and medical analyzes. In this review, the definitive applications of SERS developed to identify biochemically important species (especially medical and biological) from the simplest to the most complex are briefly discussed. Moreover, the potential capability of SERS for being used as an alternative to routine methods in diagnostic and clinical cases is demonstrated. In addition, this article describes how SERS-based sensors work, addresses its advancements in the last 20 years, discusses its applications for detecting Coronavirus Disease 2019 (COVID-19), and finally describes future works. The authors hope that this article will be useful for researchers who want to enter this amazing field of research.

Urtica dioica Agglutinin: A plant protein candidate for inhibition of SARS-COV-2 receptor-binding domain for control of Covid19 Infection

Abstract: Despite using effective drugs and vaccines for Covid 19, due to some limitations of current strategies and the high rate of coronavirus mutation, the development of medicines with effective inhibitory activity against this infection is essential. The SARS-CoV-2 enters the cell by attaching its receptor-binding domain (RBD) of Spike to angiotensin-converting enzyme-2 (ACE2). According to previous studies, the natural peptide Urtica dioica agglutinin (UDA) exhibited an antiviral effect on SARS-CoV, but its mechanism has not precisely been elucidated. Here, we studied the interaction between UDA and RBD of Spike protein of SARS-CoV-2. So, protein-protein docking of RBD-UDA was performed using Cluspro 2.0. To further confirm the stability of the complex, the RBD-UDA docked complex with higher binding affinity was studied using Molecular Dynamic simulation (via Gromacs 2020.2), and MM-PBSA calculated the binding free energy of the system. In addition, ELISA assay was used to examine the binding of UDA with RBD protein. Results were compared to ELISA of RBD-bound samples of convalescent serum IgG (from donors who recovered from Covid 19). Finally, the toxicity of UDA is assessed by using MTT assay. The docking results show UDA binds to the RBD binding site. MD simulation illustrates the UDA-RBD complex is stable during 100 ns of simulation, and the average binding energy was calculated to be -47.505 kJ/mol. ELISA and, MTT results show that UDA binds to RBD like IgG-RBD binding and may be safe in human cells. Data presented here indicate UDA interaction with S-protein inhibits the binding sites of RBD, it can prevent the virus from attaching to ACE2 and entering the host cell.

Torsional Vibration of Functionally Porous Nanotube Based on Nonlocal Couple Stress Theory

Abstract: Presented in this paper is a numerical solution for torsional vibration analysis of a functionally porous nanotube under a magnetic field. The size effect in microscale can be captured using the nonlocal couple stress theory that predicts softening and hardening in micro-size. The torsional vibration of functionally porous nanotube with magnetic field based on nonlocal couple stress theory is examined. The governing equation is derived using Hamilton’s principle and the generalized differential quadrature method (GDQM) was employed to solve it. A comparison between the results of this work with the other paper reveals the accuracy of this study. The effects of some parameters such as porosity, magnetic field, and small-scale parameters were investigated. The results show that different materials have different behavior in micro-size that can be covered softening and hardening.

Antiviral Effect of Saffron Compounds on the GP120 of HIV‐1: an In Silico Study

Abstract: Since most anti-HIV-1 drugs must penetrate host cells to prevent viral replication, developing viral inhibitors as drugs is essential because they inactivate viruses before binding to host cells. gp120 HIV-1 surface glycoprotein, which has a role in the first stages of HIV-1 infection and entrance of the virus to the cell, is one of the proper molecules for targeted therapy. The phenylalanine-43 cavity located protectively between the inner and outer domains of gp120 of several virus variants has been an attractive medical target for its interaction with CD4. Contrary to industrial drugs, saffron‘s bioactivity has recently been noticed due to its bio-accessibility and bioavailability, low toxicity, and ease of production. Due to its carotenoid content, this study examined, for the first time, the main components of saffron (Crocin, Picrocrocin, Safranal and Crocetin) for their ability to inhibit viral-cellular membrane fusion and inactivate cell-free HIV-1.The dockings were performed using Autodock Vina Software to study the interactions between the saffron compounds mentioned above with gp120 and CD4 separately. Hence, the dockings were done using Autodock Vina software. The results showed that Crocin and Picrocrocin compounds attach to the protected Phe43 Cavity and Asp368, Trp427, and Ile371 (binding site) of gp120. To confirm the stability, the best complexes of docking were studied using molecular dynamic simulation (via Gromacs 2020.2). It was observed that Crocin keeps its attachment for 100 ns of the simulation, but Picrocrocin detaches. In the end, the binding affinity of Crocin and gp120 was calculated in the 100 snapshots of the last 10 ns of simulations using PRODIGY, which was −10.3 kcal/mol. Finally, Crocin was suggested as a treatment for AIDS. Based on our atomic-level studies, we have determined that Crocin can stably bind to gp120 but not to human CD4+ T cells in the absence of HIV-1.