فصلنامه مواد پیشرفته در مهندسی
سال چهل و سوم شماره 1 (بهار 1403)

The objective of the current study is to synthesize magnetic microgels containing cobalt ferrite nanorods, surface modified with aptamer, for efficient separation and identification of breast cancer cells in the presence of a magnetic field. To construct magnetic microgels, cobalt ferrite nanorods were synthesized at 600 °C with a 5 wt.% of polyvinyl alcohol. The synthesized cobalt ferrite nanorods were successfully coated with chitosan, and then the coated nanorods were loaded into alginate microgels. Magnetic microgel samples were synthesized at different pH levels to achieve the optimal magnetic microgels. The sample synthesized at pH 7 of alginate solution and a final pH of 3 (7alg-3) was chosen due to its better size of the porosity and the percentage of surface porosity. Scanning electron microscopy test was conducted to investigate the morphological, and structural properties of nanorods and magnetic microgels. Finally, the surface of the optimal microgel was modified with mucin 1 aptamer, and visible-UV spectroscopy tests were performed to examine the aptamer attachment to the microgel surface. As a result of these efforts, a magnetic aptasensor capable of detecting MCF7 cancer cells and measuring saturation magnetization was developed. Physical and structural properties of the magnetic aptasensor and its components were investigated using scanning electron microscopy, visible-UV spectroscopy, and vibrating sample magnetometry tests. The detection limit and sensitivity of the aptasensor were measured, resulting in 14 cells/mL and a sensitivity of 0.18 Ms/cell.

Skin wounds caused by burns, physical injuries, and diseases such as diabetes can lead to amputation and even death of people due to infection and lack of proper angiogenesis. In this research, a wound dressing was made using the electrospinning method from a blend of poly-caprolactone and gelatin polymers which Ciprofloxacin and Vitamin C were loaded in the polymers separately. The morphology of the structure was observed by scanning electron microscope followed by evaluation of hydrophilicity, swelling, degradation rate, tensile strength, and drug release pattern. Fibroblast cell response was also considered using cytotoxicity test method. Results showed that the wound dressing fibers without drugs and containing drugs were uniform with a diameter of 1039.246 ± 96 and 1403± 406 nm, respectively. The wound dressing showed a suitable wide range of swelling ability and durability within 35 days. The tensile strength increased up to 3.5times by addition of ciprofloxacin and vitamin C due to the morphological changes. The presence of drugs in the system did not indicate any adverse effect on the cell's viability, and suitable proliferation and  adhesion of skin fibroblast cells were observed on the surface of the sample.  In addition,  a combination  of gelatin and polycaprolactone polymers could provide an appropriate degradation rate and release pattern without any cross-linking process, while preserving the mechanical properties and flexibility.

In this research, copper nanoparticles were synthesized via laser ablation in liquid using a nanosecond Nd:YAG laser. First, the effect of wavelengths of 532 nm and 1064 nm on the synthesis of copper nanoparticles in acetone and distilled water was investigated. After finding the appropriate wavelength, the effect of synthesis media in the presence of surfactants containing cetyltrimethylammonium chloride, sodium dodecyl sulfate, and polyvinyl pyrrolidone on copper nanoparticles was studied. Visible-ultraviolet optical spectroscopy, atomic absorption spectroscopy, dynamic light diffraction, and field emission scanning electron microscopy were employed to investigate the optical properties, synthesis efficiency, size, and morphology of copper nanoparticles prepared by the laser ablation in liquid method, respectively. The results showed that copper nanoparticles could be successfully synthesized in an acetone medium at 1064 nm wavelength. Also, due to the formation of copper oxides instead of copper nanoparticles, there is a slight possibility of preparing copper nanoparticles in aqueous environments.

Syntactic foams consisting of vinyl ester resin hollow glass microspheres (microballoons) are used in many marine or air structures due to their low density, high stiffness/density ratio, and ability to absorb energy. In this research, pure vinyl ester resin with three different volume percentages of 20%, 40%, and 60% of glass microballoons was produced by molding and casting method. The effect of the percentage of microballoons on the density, compressive, and tensile properties of foams was evaluated. The density measurement of the foams showed that with the increase in the percentage of glass microballoons, from 0% to 60% by volume, the density decreased from 1.04 g/cm3 to 0.563 g/cm3. The results showed that with the increase in the percentage of microballoons, the compressive and tensile strength of the foams decrease, but the specific compressive strength (compressive strength to density ratio) of foams increases. The highest tensile strength is related to the vinyl ester resin without microballoons with a tensile strength of 40 MPa. The specific compressive strength of foams increased from 76 MPa.cm3/g to 98 MPa.cm3/g by increasing the percentage of glass microballoon from 0% to 60%.

In this research, zinc oxide semiconductor nanoparticles doped with copper and iron elements were synthesized by the reverse co-precipitation method and their electrical and magnetic properties were investigated. The results of XRD analysis of ZnO nanoparticles showed that high-purity nanoparticles were produced, and the presence of the added dopants did not change the hexagonal structure of zinc oxide despite the slight changes in crystallite size. Besides, the results of the FESEM analysis revealed the morphology and the size of 25 nm for the nanoparticles. Furthermore, the results of PL and DRS-UV analysis showed that the band gap and optical and electrical properties of the dopant zinc oxide nanoparticles have been enhanced compared to the zinc oxide. Finally, the magnetic characteristics of these nanoparticles was investigated using the VSM analysis, and the results showed appropriate ferromagnetic properties. In conclusion, the results demonstrate the success of the reverse co-deposition method by using a non-ionic surfactant (Span 80) in the production of Cu2+- doped and Fe2+- doped ZnO nanoparticles.

In this research, 68S bioactive glass contaminated with strontium was synthesized at stabilization temperatures of 600-800 °C by sol-gel method, and the effect of stabilization temperature on the in vitro bioactive properties, before and after 14 days of immersion in Simulated body Fluid was investigated by characterization tests and bioassays. According to the results of thermal tests, the weight loss of the sample up to 620 °C was observed due to the removal of nitrate from the bioactive glass structure and the stability of its weight loss at 700 °C. The results of X-ray Diffraction, Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy indicated the formation of hydroxyapatite layer on the 3rd and 5th day of immersion and their height increase until the 14th day of immersion for 68S7C and 68S8C samples, respectively. Also, according to the results of the Inductively Coupled Plasma test, the higher formation rate of hydroxyapatite layer on the surface of the 68S7C sample compared to the 68S8C sample was confirmed. In addition, according to the results of cytotoxicity and alkaline phosphatase tests, the growth and cell proliferation of MC3T3-E1 osteogenic cells in the 68S7C sample compared to the 68S8C sample improved by 13% and 7%, respectively. Therefore, according to the results of the tests, the 68S7C sample due to its stabilization at the optimal temperature of 700 °C, the controlled rate of destruction of the glass network, having a higher formation rate of hydroxyapatite layer, improving the growth and cell proliferation of MC3T3-E1 bone-forming cells and consequently improving its biocompatibility, was selected and introduced as a reliable option for bone tissue engineering therapeutic applications.