Development of solid phase immunoradiometric assay for determination of carcinoembryonic antigen as a tumor marker

A novel aptasensor platform for the detection of carcinoembryonic antigen using quartz crystal microbalance

In this study, a quartz crystal microbalance (QCM) aptasensor for carcinoembryonic antigen (CEA), a well-known biomarker for various cancer types, was reported, utilizing two different aptamers. To achieve this, a nanofilm of 4-mercaptophenyl was electrochemically attached to gold-coated QCM crystal surfaces via the reduction of 4-mercaptobenzenediazonium salt (4 MB-DAT) using cyclic voltammetry. Subsequently, gold nanoparticles (AuNP) were affixed to this structure, and then aptamers (antiCEA1 and antiCEA2) modified with SH-functional ends bound to AuNPs completed the modification. The analytical performance of the CEA sensor was evaluated through simultaneous QCM measurements employing CEA solutions ranging from 0.1 ng/mL to 25 ng/mL. The detection limit (LOD) for CEA was determined to be 102 pg/mL for antiCEA1 and 108 pg/mL for antiCEA2 aptamers. Interday and intraday precision and accuracy tests yielded maximum results of 4.3 and + 3.8, respectively, for both aptasensors, as measured by relative standard deviation (RSD%) and relative error (RE%). The kinetic data of the aptasensors resulted in affinity values (KD) of 0.43 ± 0.14 nM for antiCEA1 and 0.75 ± 0.42 nM for antiCEA2. These values were lower than the reported values of 3.9 nM and 37.8 nM for both aptamers, respectively. The selectivity of the aptasensor was evaluated by measuring the signal changes caused by alpha-fetoprotein (AFP), cancer antigen (CA-125), and vascular endothelial growth factor (VEGF-165) individually and together at a concentration of 500 ng/mL, resulting in a maximum 4.1 % change, which was comparable to precision and accuracy values reported in the literature. After confirming the selectivity of the aptamers, recovery experiments were conducted using spiked commercial serum samples to simulate real samples, and the lowest recovery value obtained was 95.4 %. It was determined that two different aptasensors could be successfully used for the QCM-based detection of CEA in this study.

One-Step Electrochemical Sensing of CA-125 Using Onion Oil-Based Novel Organohydrogels as the Matrices

To reduce the high mortality rates caused by ovarian cancer, creating high-sensitivity, quick, basic, and inexpensive methods for following cancer antigen 125 (CA-125) levels in blood tests is of extraordinary significance. CA-125 is known as the exclusive glycoprotein employed in clinical examinations to monitor and diagnose ovarian cancer and detect its relapses as a tumor marker. Elevated concentrations of this antigen are linked to the occurrence of ovarian cancer. Herein, we designed organohydrogels (ONOHs) for identifying the level of CA-125 antigen at fast and high sensitivity with electrochemical strategies in a serum medium. The ONOH structures are synthesized with glycerol, agar, and glutaraldehyde and at distinct ratios of onion oil, and then, the ONOHs are characterized with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Electrochemical measurements are performed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) in the absence and presence of CA-125 on the designed ONOHs. For the prepared ONOH-3 electrode, two distinct linear ranges are determined as 0.41-8.3 and 8.3-249.0 U/mL. The limit of quantitation and limit of detection values are calculated as 2.415 and 0.805 μU/mL, respectively, (S/N = 3). These results prove that the developed electrode material has high sensitivity, stability, and selectivity for the detection of the CA-125 antigen. In addition, this study can be reasonable for the practical detection of CA125 in serum, permitting early cancer diagnostics and convenient treatment.

Development of a liquid phase radioimmunoassay for the measurement of serum ferritin levels for the detection of Covid-19 in patients

The aim of this study was the development and analytically validation of a radioimmunoassay system for the measurement of the serum ferritin concentration as one of the laboratory biomarkers for infection by Covid-19. The main components of the system were prepared in our laboratories. The first component ferritin was extracted and purified from human spleen with high purity. The second component was the 125I-labelled ferritin tracer, prepared using Chloramine-T method. Furthermore anti-ferritin antibodies and ferritin standards were provided. The developed system is sensitive, precise, reproducible and.

can be translated into a kit formulation suitable for measuring serum ferritin for the detection of Covid-19 in patients at low costs and high efficiency.

Development of novel lab-on-a-chip platform for high-throughput radioimmunoassay

Radioimmunoassay (RIA) is an extremely specific and a highly sensitive type of immunoassay, but the long incubation time and generation of radioactive wastes limit the use of RIA. To complement these disadvantages of RIA, we suggest an advanced type of RIA based on a lab-on-a-chip (LOC) platform: μ-RIA. We designed a microfluidic chip for RIA and optimized the procedures of μ-RIA analysis, including surface modification, immunoreaction time, and washing. Based on the optimized conditions, we conducted a radioimmunoassay on the μ-RIA platform using a commercial RIA kit. With the μ-RIA, 5 min are adequate for analysis. The amount of reagent consumption is significantly reduced compared with conventional RIA. The standard curve with R² = 0.9951 shows that we can quantitatively evaluate the amount of antigen present in unknown samples. We show the applicability of μ-RIA for the analysis of biomolecules and the potential of μ-RIA to be a novel platform for high-throughput analysis.

Extraction, purification of prostate-specific antigen (PSA), and establishment of radioimmunoassay system as a diagnostic tool for prostate disorders

This study aimed to provide an easy and effective method for extraction and purification of prostate-specific antigen (PSA) from human seminal fluid with high quantity (14 mg) and high purity (98%). The obtained PSA was injected into rabbits for production of anti-PSA polyclonal antibody (titer 1/1000), labeled with radioactive iodine-125 for preparation of radioactive PSA tracer (purity 98 ± 1.8% and specific activity 64 ± 1.9 µCi/µg), and used in preparation of PSA standards. All prepared components can be used in PSA immunoassays specially radioimmunoassay (RIA) kit preparation as a diagnostic tool for prostatic diseases.