abdolreza simchi

The human amniotic membrane (HAM) is one of the rare allograft tissues that are in use in clinical trials. Biocompatibility, antibacterial effect, low immunogenicity, and scar prevention are properties that have made HAM attractive for tissue engineering (TE) applications, for example, as a cell carrier, injectable hydrogel, and cell culture substrate. In this research, the effect of digestion time on the structure, gelation kinetics, rheological and biological properties of amniotic membrane-derived hydrogels was studied. The results determined that digestion with pepsin should be performed at least for 24 h.  Prolonging the digestion time to 72 h increased the shear modulus, fiber diameter, and gelation rate. Cytocompatibility assays with L929 fibroblast cells showed that the digestion time had no effect on the cell toxicity of the hydrogels. However, cell proliferation was improved due to preserved constitutive bioactive molecules. The results of this research can be used to develop amniotic membrane-derived hydrogels for TE applications.

The inability of classic fluorescence-activated cell sorting to single cancer cell sorting is one of the most significant drawbacks of this method. The sorting of cancer cells in microdroplets significantly influences our ability to analyze cancer cell proteins.

We adapted a developed microfluidic device as a 3D in vitro model to sorted MCF-7 cancer cells on a chip. A prefabricated microfluidic droplet chip was used in this research. Then, with the help of synthesized fluorescent probes, MCF-7 cancer cells were separated from normal cells.

This research presents a modification of GQD bead for high-throughput analysis and sorting single cancer cells. We elaborate a binding assay as an example of this approach for detecting MCF-7 cancer cell lines. Graphene quantum dot-decorated mesoporous silica nanoparticles (GQD@MSNPs) act as fluorescent optical beads coated in microfluidic droplets. The fluorescent beads capture cancer cells. To enable droplet sorting at 200 Hz and cell enrichment, a measurable fluorescence signal is generated when cancer cells bind to these beads and boost the drop's fluorescence emission.

Herein, we report in vitro results showing that the as-prepared GQD@MSNs have exceptional luminous characteristics. The specific surface area and pore volume of GQD-MSNs were found to be 50% and 40% higher than those of pure MSNs, which is rather remarkable. Because of these improved qualities, GQD@MSNs are demonstrated a large sorting capacity that makes them ideal for diagnosis.

The Current investigation was designed to study different steps of powder injection molding of Stainless Steel/TiC Composite. So a multi-component binder was selected and its melting, recrystallization and degradation temperatures were evaluated via DSC and TGA experiments. In order to study the rheological behavior of feedstock, a capillary rheometer was incorporated and the effects of shear rate, TiC content, temperature and solid loading on rheological behavior of feedstock were investigated and based on the results the best feedstock and processing temperature were selected. In the next step, some samples were injection molded at two temperatures (93 and 115 oC) and two pressures (5 and 10 MPa). Results showed that by increasing temperature from 60oC to 70oc the viscosity decreased 20% but will be stable in higher temperature. The viscosity of all sample was below 1000 Pa.s. the calculated solid loading was 64%. By adding TiC particles, the green density of samples decreased from 4.85 gr/cm3 to 4.7 gr/cm3.

The fabrication of complex-shaped parts out of (wt %) Co-28Cr-6Mo alloy by three-dimensional printing (3DP) was studied using two grades of the alloy with average particle sizes of 20 and 75 μm. To produce sound specimens, 3DP processing parameters were tuned. The sintering behavior of the powders was characterized by the dilatometric analysis. Batch sintering in argon atmosphere at 1280 °C for 2h was also performed. It was shown that complex-shaped biomedical parts with total porosity of 12-25% and homogenous pore structure can be fabricated by the 3DP process.