Showing papers by "Ramin Ghahremanzadeh published in 2019"

Antibody-Drug Conjugates: Possibilities and Challenges.

Abstract: The design of Antibody Drug Conjugates (ADCs) as efficient targeting agents for tumor cell is still in its infancy for clinical applications. This approach incorporates the antibody specificity and cell killing activity of chemically conjugated cytotoxic agents. Antibody in ADC structure acts as a targeting agent and a nanoscale carrier to deliver a therapeutic dose of cytotoxic cargo into desired tumor cells. Early ADCs encountered major obstacles including, low blood residency time, low penetration capacity to tumor microenvironment, low payload potency, immunogenicity, unusual off-target toxicity, drug resistance, and the lack of stable linkage in blood circulation. Although extensive studies have been conducted to overcome these issues, the ADCs based therapies are still far from having high-efficient clinical outcomes. This review outlines the key characteristics of ADCs including tumor marker, antibody, cytotoxic payload, and linkage strategy with a focus on technical improvement and some future trends in the pipeline.

Electroactive graphene oxide‐incorporated collagen assisting vascularization for cardiac tissue engineering

Abstract: The application of a cardiac patch over the epicardial surface has shown positive effects in protecting cardiac function postinfarction. Electroactive patches could enhance electrical signal propagation among cardiac cells. In the present study, an electrically active composite of collagen and graphene oxide (Col-GO) was fabricated as a cardiac patch. Col scaffolds were fabricated using a freeze-drying method and coated covalently with GO. Some scaffolds were also reduced by a reduction agent to restore the high conductivity of GO. GO was shown to be a single layer with suitable lateral size for biological application. The Col-GO scaffolds contained randomly oriented interconnected pores with appropriate pore sizes of 120-138 ± 8 μm. GO flakes were also well distributed in the pore walls. By increasing the GO concentration, the tensile strength of the scaffolds was enhanced from 75 kPa for Col-GO-5 to 162 kPa for Col-GO-90. Young modulus also followed the same trend. Electrical conductivity of the scaffolds was in the range of semi-conductive materials (~10-4 S/m), which is suitable for cardiac tissue engineering applications. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay indicated no toxic effects on human umbilical vein endothelial cells (HUVECs) after 96 h. Also, a 10-days degradation product of the samples was compatible with HUVECs. Reduced scaffolds supported neonatal cardiomyocyte adhesion and upregulated the expression of the cardiac genes, including Cx43, Actin4, and Trpt-2 than their nonconductive counterparts. The obtained results confirmed the angiogenic properties of reduced Go-containing materials for cardiovascular applications where angiogenesis plays an important role, especially postinfarction. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 204-219, 2019.

Green synthesis, characterization and antimicrobial activity of silver nanoparticles (AgNPs) using leaves and stems extract of some plants

Abstract: Green synthesis of silver nanoparticles using the aqueous extract of Ferula gumosa, Ferula latisecta, Teucrium polium and Trachomitum venetum leaves and stems extract as the reducing and stabilizing agents. This synthesis shows attractive characteristics such as; the use of inexpensive and available plant extracts, non-toxicity, eco-friendly biological materials, and operational simplicity. The extracts incubated with AgNO3 solution showed gradual change in color of the extracts to yellowish brown, with intensity increasing during the period of incubation. The nanoparticles were characterized by UV–visible absorption spectroscopy, X-ray diffraction (XRD) spectroscopy, Dynamic Light Scattering (DLS), and Transmission Electron Microscope (TEM). The silver nanoparticles synthesized were generally found to be spherical in shape with variable size ranging from 5 to 30 nm, as evident by TEM. The biosynthesized silver nanoparticles (AgNPs) showed good antibacterial activity against clinical strains of two bacteria Staphylococcus aureus and Escherichia coli.

Reduced graphene oxide: osteogenic potential for bone tissue engineering

Abstract: Collagen (Col) type I, as the major component of the bone extracellular matrix has been broadly studied for bone tissue engineering. However,inferior mechanical properties limit its usage for load bearing applications. In this research, freeze dried Col scaffolds are coated with graphene oxide (GO) through a covalent bond of the amine Col with the graphene carboxyl groups. The prepared scaffolds were then reduced using a chemical agent. Scanning electron microscopy exhibited a porous structure for the synthesized scaffolds with an approximate pore size of 100-220 ± 12 µm, which is in the suitable range for bone tissue engineering application. Reducing the GO coating improved the compressive modulus of the Col from 250 to 970 kPa. Apatite formation was also indicated by immersing the scaffolds in simulated body fluid after five days. The cytocompatibility of the scaffolds, using human bone marrow-derived mesenchymal stem cells, was confirmed with MTT analysis. Alkaline phosphatase assay revealed that reducing the Col-GO scaffolds can effectively activate the differentiation of hBM-MSCs into osteoblasts after 14 days, even without the addition of an osteogenic differentiation medium. The results of this study highlight that GO and its reduced form have considerable potential as bone substitutes for orthopaedic and dental applications.

Green Synthesis of Gold Nanoparticles Using Three Medicinal Plant Extracts as Efficient Reducing Agents

Abstract: The aim of this work is a green synthesis of gold nanoparticles using the aqueous extract of Anthriscus sylvestris, Ferula gummosa, and Achillea eriohora leaf and stems as the reducing agents. The effects of reducing agent concentration in the reaction mixture and temperature on the size of the gold nanotriangles were studied. The nanoparticles were characterized using UV–Vis spectroscopy, XRD, and SEM. XRD studies show that the particles are crystalline in the cubic phase. However, the reduction of gold ions by plant extracts resulted in the formation of spherical gold nanoparticles with diameters from 18 to 56 nm.