A nanocomposite containing Prussian Blue, platinum nanoparticles and polyaniline for multi-amplification of the signal of voltammetric immunosensors: highly sensitive detection of carcinoma antigen 125

Ultrasensitive and label-free electrochemical immunosensor for the detection of the ovarian cancer biomarker CA125 based on CuCo-ONSs@AuNPs nanocomposites

Cancer antigen 125 (CA125) is pivotal as a tumor marker in early ovarian cancer prevention and diagnosis. In this work, we introduced an ultrasensitive label-free electrochemical immunosensor tailored for CA125 detection, leveraging nanogold-functionalized copper-cobalt oxide nanosheets (CuCo-ONSs@AuNPs) as nanocomposites. For the inaugural application, copper-cobalt oxide nanosheets delivered the requisite DPV electrochemical response for the immunosensors. Their large specific surface area and commendable electrical conductivity amplify electron transfer and enable significant gold nanoparticle loading. Concurrently, AuNPs offer a plethora of active sites, facilitating easy immobilization of biomolecules via the bond between amino groups and AuNPs. We employed scanning electron microscopy, transmission electron microscopy, and x-ray photoelectron spectroscopy to characterize the nanomaterials' surface morphology and elemental composition. The electrochemical sensor response signals were ascertained using differential pulse voltammetry. Under optimal conditions, the immunosensor exhibited a linear detection range from 1×10-7 U/mL to 1×10-3 U/mL and a detection limit of 3.9×10-8 U/mL (S/N=3). The proposed label-free electrochemical immunosensor furnishes a straightforward, dependable, and sensitive approach for CA125 quantification and stands as a promising method for clinical detection of other tumor markers.

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.

Electrochemical and Photoelectrochemical Immunosensors for the Detection of Ovarian Cancer Biomarkers

Photoelectrochemical (PEC) sensing is an emerging technological innovation for monitoring small substances/molecules in biological or non-biological systems. In particular, there has been a surge of interest in developing PEC devices for determining molecules of clinical significance. This is especially the case for molecules that are markers for serious and deadly medical conditions. The increased interest in PEC sensors to monitor such biomarkers can be attributed to the many apparent advantages of the PEC system, including an enhanced measurable signal, high potential for miniaturization, rapid testing, and low cost, amongst others. The growing number of published research reports on the subject calls for a comprehensive review of the various findings. This article is a review of studies on electrochemical (EC) and PEC sensors for ovarian cancer biomarkers in the last seven years (2016-2022). EC sensors were included because PEC is an improved EC; and a comparison of both systems has, expectedly, been carried out in many studies. Specific attention was given to the different markers of ovarian cancer and the EC/PEC sensing platforms developed for their detection/quantification. Relevant articles were sourced from the following databases: Scopus, PubMed Central, Web of Science, Science Direct, Academic Search Complete, EBSCO, CORE, Directory of open Access Journals (DOAJ), Public Library of Science (PLOS), BioMed Central (BMC), Semantic Scholar, Research Gate, SciELO, Wiley Online Library, Elsevier and SpringerLink.

Preparation of a pH-responsive controlled-release electrochemical immunosensor based on polydopamine encapsulation for ultrasensitive detection of alpha-fetoprotein

To accomplish ultra-sensitive detection of alpha-fetoprotein(AFP), a novel electrochemical immunosensor using polydopamine-coated Fe₃O₄ nanoparticles (PDA@Fe₃O₄ NPs) as a smart label and polyaniline (PANI) and Au NPs as substrate materials has been created. The sensor has the following advantages over typical immunoassay technology: (1) The pH reaction causes PDA@Fe₃O₄ NPs to release Prussian blue (PB) prosoma while also destroying the secondary antibody label and immunological platform and lowering electrode impedance; (2) PB has a highly efficient catalytic effect on H₂O₂, allowing for the obvious amplification of electrical impulses; (3) PANI was electrodeposited on the electrode surface to avoid PB loss and signal leakage, which effectively absorbed and fixed PB while considerably increasing electron transmission efficiency. The sensor's detection limit was 0.254 pg·mL^-1 (S/N = 3), with a detection range of 1 pg·mL^-1 to 100 ng·mL^-1. The sensor has a high level of selectivity, repeatability, and stability, and it is predicted to be utilized to detect AFP in real-world samples.

Biomarkers for Early Diagnosis of Ovarian Carcinoma

The leading cause of gynecological cancer-related morbidity and mortality is ovarian cancer (OC), which is dubbed a silent killer. Currently, OC is a target of intense biomarker research, because it is often not discovered until the disease is advanced. The goal of OC research is to develop effective tests using biomarkers that can detect the disease at the earliest stages, which would eventually decrease the mortality, thereby preventing recurrence. Therefore, there is a pressing need to revisit the existing biomarkers to recognize the potential biomarkers that can lead to efficient predictors for the OC diagnosis. This Perspective covers an update on the currently available biomarkers used in the triaging of OC to gain certain insights into the potential role of these biomarkers and their estimation that are crucial to the understanding of neoplasm progression, diagnostics, and therapy.

Nanotechnology-based approaches for effective detection of tumor markers: A comprehensive state-of-the-art review

As well-appreciated biomarkers, tumor markers have been spotlighted as reliable tools for predicting the behavior of different tumors and helping clinicians ascertain the type of molecular mechanism of tumorigenesis. The sensitivity and specificity of these markers have made them an object of even broader interest for sensitive detection and staging of various cancers. Enzyme-linked immunosorbent assay (ELISA), fluorescence-based, mass-based, and electrochemical-based detections are current techniques for sensing tumor markers. Although some of these techniques provide good selectivity, certain obstacles, including a low sample concentration or difficulty carrying out the measurement, limit their application. With the advent of nanotechnology, many studies have been carried out to synthesize and employ nanomaterials (NMs) in sensing techniques to determine these tumor markers at low concentrations. The fabrication, sensitivity, design, and multiplexing of sensing techniques have been uplifted due to the attractive features of NMs. Various NMs, such as magnetic and metal nanoparticles, up-conversion NPs, carbon nanotubes (CNTs), carbon-based NMs, quantum dots (QDs), and graphene-based nanosensors, hyperbranched polymers, optical nanosensors, piezoelectric biosensors, paper-based biosensors, microfluidic-based lab-on-chip sensors, and hybrid NMs have proven effective in detecting tumor markers with great sensitivity and selectivity. This review summarizes various categories of NMs for detecting these valuable markers, such as prostate-specific antigen (PSA), human carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), human epidermal growth factor receptor-2 (HER2), cancer antigen 125 (CA125), cancer antigen 15-3 (CA15-3, MUC1), and cancer antigen 19-9 (CA19-9), and highlights recent nanotechnology-based advancements in detection of these prognostic biomarkers.

Nanostructure-Based Electrochemical Immunosensors as Diagnostic Tools

Electrochemical immunosensors are affinity-based biosensors characterized by several useful features such as specificity, miniaturizability, low cost and simplicity, making them very interesting for many applications in several scientific fields. One of the significant issues in the design of electrochemical immunosensors is to increase the system’s sensitivity. Different strategies have been developed, one of the most common is the use of nanostructured materials as electrode materials, nanocarriers, electroactive or electrocatalytic nanotracers because of their abilities in signal amplification and biocompatibility. In this review, we will consider some of the most used nanostructures employed in the development of electrochemical immunosensors (e.g., metallic nanoparticles, graphene, carbon nanotubes) and many other still uncommon nanomaterials. Furthermore, their diagnostic applications in the last decade will be discussed, referring to two relevant issues of present-day: the detection of tumor markers and viruses.

Gold Microstructures/Polyaniline/Reduced Graphene Oxide/Prussian Blue Composite as Stable Redox Matrix for Label-free Electrochemical Immunoassay of α-Fetoprotein

Sensitivity amplification strategies in label-free electrochemical immunosensors are mainly limited by redox molecules leaking and degradation of electrical conductivity caused by layers of decoration. Herein, a relatively stable and sensitive label-free electrochemical immunosensor based on a hierarchically flower-like gold microstructures/polyaniline/reduced graphene oxide/prussian blue (HFG/PANI/rGO/PB) composite modified electrode was stepwise fabricated for determination of α-fetoprotein (AFP). In this process, the effect of PANI and rGO on the proposed immunosensor was studied. In detail, PANI/rGO due to the unique electrochemical properties can effectively prevent PB leakage and form a stable sensing platform, which causes sensitive responsiveness and thus a more satisfied detection limit. Meanwhile, the HFG with good biological compatibility can effectively immobilize plenty of antibodies. Under optimal conditions, the HFG/PANI/rGO/PB modified immunosensor exhibited an excellent linearity (0.01 - 30 ng/mL) and a low detection limit (0.003 ng/mL) (S/N = 3), suitable specificity as well as stability and reproducibility towards AFP. The present work offered a promising platform for clinical hepatocellular carcinoma diagnostics.

Recent advancements in fabrication of nanomaterial based biosensors for diagnosis of ovarian cancer: a comprehensive review

Ovarian cancer is commonly diagnosed via determination of biomarkers like CA125, Mucin 1, HE4, and prostasin that can be present in the blood. However, there is a substantial need for less expensive, simpler, and portable diagnostic tools, both for timely diagnosis and management of ovarian cancer. This review (with 101 refs.) discusses various kinds of nanomaterial-based biosensors for tumor markers. Following an introduction into the field, a first section covers different kinds of biomarkers for ovarian cancer including CA125 (MUC16), mucin 1 (MUC1), human epididymis protein 4 (HE4), and prostasin. This is followed by a short overview on conventional diagnostic approaches. A large section is then presented on biosensors for determination of ovarian cancer, with subsections on optical biosensors (fluorimetric, colorimetric, surface plasmon resonance, chemiluminescence, electrochemiluminescence), on electrochemical sensors, molecularly imprinted sensors, paper-based biosensors, microfluidic (lab-on-a-chip) assays, chemiresistive and field effect transistor-based sensors, and giant magnetoresistive sensors. Tables are presented that give an overview on the wealth of methods and materials. A concluding section summarizes the current status, addresses current challenges, and gives an outlook on potential future trends. Graphical abstract Schematic representation of the review covering the advancements in the fabrication of various nanomaterial based biosensors for diagnosis of ovarian cancer.

Electrochemical sensors and biosensors based on the use of polyaniline and its nanocomposites: a review on recent advances

Polyaniline and its composites with nanoparticles have been widely used in electrochemical sensor and biosensors due to their attractive properties and the option of tuning them by proper choice of materials. The review (with 191 references) describes the progress made in the recent years in polyaniline-based biosensors and their applications in clinical sensing, food quality control, and environmental monitoring. A first section summarizes the features of using polyaniline in biosensing systems. A subsequent section covers sensors for clinical applications (with subsections on the detection of cancer cells and bacteria, and sensing of glucose, uric acid, and cholesterol). Further sections discuss sensors for use in the food industry (such as for sulfite, phenolic compounds, acrylamide), and in environmental monitoring (mainly pesticides and heavy metal ions). A concluding section summarizes the current state, highlights some of the challenges currently compromising performance in biosensors and nanobiosensors, and discusses potential future directions. Graphical abstract Schematic presentation of electrochemical sensor and biosensors applications based on polyaniline/nanoparticles in various fields of human life including medicine, food industry, and environmental monitoring. The simultaneous use of suitable properties polyaniline and nanoparticles can provide the fabrication of sensing systems with high sensitivity, short response time, high signal/noise ratio, low detection limit, and wide linear range by improving conductivity and the large surface area for biomolecules immobilization.

Employing AgNPs doped amidoxime-modified polyacrylonitrile (PAN-oxime) nanofibers for target induced strand displacement-based electrochemical aptasensing of CA125 in ovarian cancer patients

In this study, a high-performance biosensing nanoplatform based on amidoxime-modified polyacrylonitrile nanofibers decorated with Ag nanoparticles (AgNPs-PAN-oxime NFs) is described. The AgNPs-PAN-oxime NFs were prepared by the combination of electrospinning technique and chemical modification of nitrile group in the PAN. The proposed signal amplifiying nanoplatform was applied in the fabrication of an electrochemical aptasensor for the sensitive detection of CA 125 based on aptamer-cDNA duplex and target induced strand displacement recognition mechanism. The aptasensing interface offers high sensitivity and selectivity for detection of tumor marker due to inherent advantages such as high specific surface area of NFs, good conductivity by doping AgNPs into the polymer NFs and especially the ideal selectivity of anti CA 125 aptamer to its target. The electrochemical aptasensor revealed a wide dynamic linear range (DLR) from 0.01 to 350 U mL^-1 with a correlation coefficient of 0.991 and limit of detection (LOD) of 0.0042 U mL^-1. Additionally, the designed aptasensor showed acceptable selectivity, reproducibility, repeatability and stability. The satisfactory results for determination of CA 125 in serum samples compared to ELISA method (p-value > 0.05) indicated the potential application of aptasensor in clinical monitoring of tumor biomarker for early diagnosis and management of ovarian cancer.