Electrochemical Biosensor Research Articles

Nanoarchitectonics of aptamer-based electrochemical biosensor utilizing electerospun carbon nanofibers and gold nanoparticles for Acinetobacter baumannii detection

Acinetobacter baumannii (A. baumannii) is a gram-negative bacterium that is responsible for causing a range of infections, including pneumonia, meningitis, and bloodstream infections and the detection of this bacterium is crucial for timely diagnosis and treatment of infections. The purpose of this work was to design and manufacture an electrochemical biosensor based on carbon nanofibers (CNFs), gold nanoparticles (AuNPs), and aptamer that could detect A. baumannii in urine samples. At first, polyacrylonitrile (PAN) polymer was electrospun and CNFs were formed during two stages of heat treatment including stabilization and carbonization, and Raman spectroscopy and X-ray diffraction (XRD) were used to characterize it. Then, these CNFs were used to modify the surface of the screen-printed carbon electrode (SPCE), and AuNPs were placed on the SPCE modified with CNFs using the electrodeposition method. Field emission scanning electron microscopy (FESEM) and energy dispersive X-Ray spectroscopy (EDS) were used to study the surface morphology of the modified electrode to determine the carbon and gold elements, respectively. Then the aptamer related to A. baumannii was placed on this modified electrode using a simple and cost-effective process and characterized by the cyclic voltammetry (CV) technique. Next, the spiked A. baumannii in urine samples was detected by this aptasensor in the range of 101 to 106 cfu mL−1 and limit of detection (LOD) to 0.681 cfu mL−1 and limit of quantitation (LOQ) to 2.27 cfu mL−1 with differential pulse voltammetry (DPV) technique. Salmonella typhimurium, Staphylococcus aureus and E. Coli were used to perform the selectivity test. In addition, its repeatability was checked and its stability for 30 days was more than 96 %. Finally, the results of this aptasensor were compared with the conventional method of bacterial culture, and this aptasensor was able to detect A. baumannii in a less time and with more sensitivity.

Large‐Scale Flexible Fabric Biosensor for Long‐Term Monitoring of Sweat Lactate

AbstractIntegrating sweat biosensors into daily wear has the potential to effectively monitor personal lactate levels, offering the advantages of convenience, precision, and multi‐point detection. However, existing wearable fabric sweat biosensors have limitations in terms of long‐term repeatable detection and washability due to the difficulty of building a stable layer of recognition materials on the highly curved fiber surface. Here, a long‐term repeatable and washable electrochemical fabric biosensor is reported based on a fiber electrode with multi‐scaled aligned channels for efficient and reliable lactate detection. Through the functionalization of a molecularly imprinted polymer with redox‐sensitive nano reporters, the fabric biosensor exhibits impressive in situ long‐term repeatable detection for more than 400 times, washability, and stability under deformations. The multi‐scaled channels contribute to a desired electric field distribution and thus a reliable interface between the polymer and the fiber. Employing industrial sewing technology, a 20 m (L)  ×  0.5 m (W) sensing fabric is further produced. Ultimately, combined with a wireless communication element, the fabric biosensing system can immediately track lactate levels.

A technique of a “lab-on-a-chip” for developing a novel biosensor in viewpoint of health-care (PHC) applications and biological regulator sensors

Purpose Recently, powerful instruments for biomedical engineering research studies, including disease modeling, drug designing and nano-drug delivering, have been extremely investigated by researchers. Particularly, investigation in various microfluidics techniques and novel biomedical approaches for microfluidic-based substrate have progressed in recent years, and therefore, various cell culture platforms have been manufactured for these types of approaches. These microinstruments, known as tissue chip platforms, mimic in vivo living tissue and exhibit more physiologically similar vitro models of human tissues. Using lab-on-a-chip technologies in vitro cell culturing quickly caused in optimized systems of tissues compared to static culture. These chipsets prepare cell culture media to mimic physiological reactions and behaviors. Design/methodology/approach The authors used the application of lab chip instruments as a versatile tool for point of health-care (PHC) applications, and the authors applied a current progress in various platforms toward biochip DNA sensors as an alternative to the general bio electrochemical sensors. Basically, optical sensing is related to the intercalation between glass surfaces containing biomolecules with fluorescence and, subsequently, its reflected light that arises from the characteristics of the chemical agents. Recently, various techniques using optical fiber have progressed significantly, and researchers apply highlighted remarks and future perspectives of these kinds of platforms for PHC applications. Findings The authors assembled several microfluidic chips through cell culture and immune-fluorescent, as well as using microscopy measurement and image analysis for RNA sequencing. By this work, several chip assemblies were fabricated, and the application of the fluidic routing mechanism enables us to provide chip-to-chip communication with a variety of tissue-on-a-chip. By lab-on-a-chip techniques, the authors exhibited that coating the cell membrane via poly-dopamine and collagen was the best cell membrane coating due to the monolayer growth and differentiation of the cell types during the differentiation period. The authors found the artificial membrane, through coating with Collagen-A, has improved the growth of mouse podocytes cells-5 compared with the fibronectin-coated membrane. Originality/value The authors could distinguish the differences across the patient cohort when they used a collagen-coated microfluidic chip. For instance, von Willebrand factor, a blood glycoprotein that promotes hemostasis, can be identified and measured through these type-coated microfluidic chips.

Combining WO3@AuNPs with Poly(amidoamine) Allows Sensitive Electrochemical Detection of DR1 Based on Dual Signal Amplification.

Down-regulator of transcription 1 (DR1) is considered as a biomarker of hashimoto's thyroiditis(HT), which is a risk factor for thyroid cancer. Here, a label-free electrochemical biosensor for DR1 detection was constructed based on polyamidoamine(PAMAM)polymer and the nanocomposite (WO3@AuNPs) composed of tungsten trioxide (WO3) and gold nanoparticles (AuNPs). WO3@AuNPs was obtained by combining monolayer WO3nanosheets, which has high conductivity, and AuNPs. The modification of WO3@AuNPs can not only increase the conductivity of the electrode but also provide more active sites for signaling units, thus greatly improve the sensitivity of the sensor. The polymer PAMAM is biocompatible and non-immunogenic, and its end functional group can bind to the target molecules, providing them with more binding sites and thus improving the sensitivity of the sensor. Under optimal conditions, the label-free biosensor showed a good linear relationship between the logarithm of DR1 concentration and the impedance in the range of 10 fg·mL-1to 100 ng·mL-1, with a detection limit as low as 0.3 fg·mL-1. Besides, this label-free electrochemical platform exhibited satisfactory selectivity and anti-interference capability in human serum samples. Therefore, this method has considerable potential in clinical detection of DR1.

Intelligent salivary biosensors for periodontitis: in vitro simulation of oral oxidative stress conditions.

One of the most common oral diseases affecting millions of people worldwide is periodontitis. Usually, proteins in body fluids are used as biomarkers of diseases. This study focused on hydrogen peroxide, lipopolysaccharide (LPS), and lactic acid as salivary non-protein biomarkers for oxidative stress conditions of periodontitis. Electrochemical analysis of artificial saliva was done using Gamry with increasing hydrogen peroxide, bLPS, and lactic acid concentrations. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were conducted. From EIS data, change in capacitance and CV plot area were calculated for each test condition. Hydrogen peroxide groups had a decrease in CV area and an increase in percentage change in capacitance, lipopolysaccharide groups had a decrease in CV area and a decrease in percentage change in capacitance, and lactic acid groups had an increase of CV area and an increase in percentage change in capacitance with increasing concentrations. These data showed a unique combination of electrochemical properties for the three biomarkers. Scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) employed to observe the change in the electrode surface and elemental composition data present on the sensor surface also showed a unique trend of elemental weight percentages. Machine learning models using hydrogen peroxide, LPS, and lactic acid electrochemical data were applied for the prediction of risk levels of periodontitis. The detection of hydrogen peroxide, LPS, and lactic acid by electrochemical biosensors indicates the potential to use these molecules as electrochemical biomarkers and use the data for ML-driven prediction tool for the periodontitis risk levels.

Self-assembly of a AuNPs/Ti3C2 MXene hydrogel for cascade amplification of microRNA-122 biosensing.

A three-dimensional (3D) self-assembled AuNPs/Ti3C2 MXene hydrogel (AuNPs/Ti3C2 MXH) nanocomposite was prepared for the fabrication of a novel microRNA-122 electrochemical biosensor. The 3D hydrogel structure was gelated from two-dimensional MXene nanosheets with the assistance of graphite oxide and ethylenediamine. MXene hydrogels supported the in situ formation of Au nanoparticles (AuNPs) that predominantly exploring the (111) facet, and these AuNPs are utilized as carriers for hairpin DNA (hpDNA) probes, facilitating DNA hybridization. MXene acted as both a reductant and stabilizer, significantly improving the electrochemical signal. In addition, the conjugation of PAMAM dendrimer-encapsulated AuNPs and H-DNA worked as an ideal bridge to connect targets and efficient electrochemical tags, providing a high amplification efficiency for the sensing of microRNA-122. A linear relationship between the peak currents and the logarithm of the concentrations of microRNA-122 from 1.0 × 10-2 to 1.0 × 102 fM(I = 1.642 + 0.312 lgc, R2 = 0.9891), is obtained. The detection limit is 0.8 × 10-2 fM (S/N = 3). The average recovery for human serum detection ranged from 97.32 to 101.4% (RSD < 5%).

An Innovative SbIII-WVI-Cotemplated Antimonotungstate with Potential in Sensing Paroxetine Electrochemically.

Advances in polyoxometalate (POM) self-assembly chemistry are always accompanied by new developments in molecular blocks. The exploration and discovery of uncommon building blocks offer great possibilities for generating unprecedented POM clusters. An intriguing SbIII-WVI-cotemplated antimonotungstate [H2N(CH3)2]11Na[SbW9O33]Er2(H2O)2Sb2[SbWVIW15O57]·22H2O (1) was synthesized, which comprises a classical trivacant Keggin [SbW9O33]9- ({SbW9}) fragment and an unclassical lacunary Dawson-like [SbWVIW15O57]15- ({SbWVIW15}) subunit. Notably, the Dawson-like {SbWVIW15} subunit is the first example of a [SbO3]3- and [WVIO6]6- mixed-heteroatom-directing POM segment. Hexacoordinated [WVIO6]6- can not only serve as the heteroatom function but its additional oxygen sites can also link to lanthanide, main-group metal, and transition-metal centers to form the innovative structure. {SbWVIW15} and {SbW9} subunits are joined by the heterometallic [Er2(H2O)2Sb2O17]22- cluster to give rise to an asymmetric sandwich-type architecture. To further realize its potential application in electrochemical sensing, a conductive 1@rGO composite was obtained by the electrochemical deposition of 1 with graphene oxide (GO). Using a 1@rGO-modified glassy carbon electrode as the working electrode, an electrochemical biosensor for detecting the antidepressant drug paroxetine (PRX) was successfully constructed. This work can provide a viable strategy for synthesizing mixed-heteroatom-directing POMs and demonstrates the application of POM-based materials for the electrochemical detection of drug molecules.

Electrochemical Sensors, Biosensors, and Optical Sensors for the Detection of Opioids and Their Analogs: Pharmaceutical, Clinical, and Forensic Applications

Pharmaceutical opioids are intravenously or orally administered analgesics. While they are effective in relieving chronic and acute pain, their narrow window of therapeutic use contributes to the high occurrence of abuse. The associated abuse of this family of drugs can be correlated to the increase in dependency, overdose, and death of users. The negative effects of opioids extend beyond the physical and psychological effects experienced by the user to their unregulated synthesis and sale, which contribute to socioeconomic challenges and are a biproduct of this global public health epidemic. From clinical to point-of-care applications, the detection and real-time monitoring of this family of drug is critical in the fight to decrease abuse and improve use in clinical settings. Chromatographic separations and chromatography–mass spectrometry are traditional methods of opioid analyses, but the high cost, long analysis time, and absence of portability highlight the need for the development of fast, in situ, point-of-care analysis, or of community drug monitoring services. This review highlights recent electrochemical and optical (FTIR, Raman, colorimetric, and fluorescent) advances and biosensors for pharmaceutical and illicit opioid analysis. Specifically, an emphasis is placed on the detection of opioids and their metabolites in biological samples and in vitro cellular assays for clinical diagnosis and forensic applications. The challenges and prospects of the role of electrochemical sensors, biosensors, and optical sensors for opioid analysis in promoting clinical diagnosis, forensic study, point-of-care, and community drug monitoring services to reduce harm are also provided.

Graphene derivative-based ink advances inkjet printing technology for fabrication of electrochemical sensors and biosensors

The field of biosensing would significantly benefit from a disruptive technology enabling flexible manufacturing of uniform electrodes. Inkjet printing holds promise for this, although realizing full electrode manufacturing with this technology remains challenging. We introduce a nitrogen-doped carboxylated graphene ink (NGA-ink) compatible with commercially available printing technologies. The water-based and additive-free NGA-ink was utilized to produce fully inkjet-printed electrodes (IPEs), which demonstrated successful electrochemical detection of the important neurotransmitter dopamine. The cost-effectiveness of NGA-ink combined with a total cost per electrode of $0.10 renders it a practical solution for customized electrode manufacturing. Furthermore, the high carboxyl group content of NGA-ink (13 wt%) presents opportunities for biomolecule immobilization, paving the way for the development of advanced state-of-the-art biosensors. This study highlights the potential of NGA inkjet-printed electrodes in revolutionizing sensor technology, offering an affordable, scalable alternative to conventional electrochemical systems.

Homogeneous electrochemical ratiometric biosensor for MircoRNA detection based on UiO-66-NH2 signal probe and waste-free entropy-driven DNA machine

The construction of efficient methods for highly sensitive and rapid detection of disease markers is essential for the early diagnosis of serious diseases. In this paper, taking advantage of the UiO-66-NH2 signal molecule in combination with a waste-free entropy-driven DNA machine, a novel homogeneous electrochemical ratiometric platform is developed to detect MircoRNA (miRNA). Metal-organic framework materials (UiO-66-NH2 MOF) and ferrocene were utilized as electrochemical signal tags and reference probes, respectively. The target-initiated waste-free three-dimensional (3D) entropy-driven DNA nanomachine is activated in the presence of miRNA, resulting in DNA-labeled-UiO-66-NH2 falling off from the electrode, leading to a decrease in the signal of UiO-66-NH2 at 0.83V. Our strategy can mitigate false positive responses induced by the DNA probes immobilized on electrodes in traditional distance-dependent signal adjustment ratiometric strategies. The proposed ratiometric platform demonstrates superior sensitivity (a detection limit of 9.8 fM), simplified operation, high selectivity, and high repeatability. The ratiometric biosensor is also applied to detect miRNA content in spiked serum samples.

Thermal conductivity of wrinkled graphene ring with defects.

Graphene rings have great prospects in the fields of biological modulators, electrochemical biosensors, and resonators, but are prone to wrinkling which can affect their physical properties. This work establishes a theoretical model predicting the torsional wrinkling behavior of defective monolayer graphene rings, which provides direct understanding and reliable accuracy of the wrinkle levels. Then the thermal conductivity of wrinkled graphene rings is studied considering different wrinkle levels, defect concentrations and radii. It is found that with increased radius, defect concentration and torsional angle, the ratio of wrinkle amplitude to wavelength increases gradually. Vacancy defects and radii have more significant influences on the thermal conductivity than torsional wrinkles. The main influence mechanism of wrinkles and defects on thermal conductivity is revealed by phonon density of state. This work provides theoretical guidance for thermal manipulation based on the wrinkle-tuning approach.

Miniaturized MXene-based electrochemical biosensors for virus detection

The timely control of infectious diseases can prevent the spread of infections and mitigate the significant socio-economic damage witnessed during recent pandemics. Diagnostic methods play a significant role in detecting highly contagious agents, such as viruses, to prevent further transmission. The emergence of advanced point-of-care techniques offers several advantages over conventional approaches for detecting infectious agents. These techniques are highly sensitive, rapid, can be miniaturized, and are cost-effective. Recently, MXene-based 2D nanocomposites have proven beneficial for fabricating electrochemical biosensors due to their suitable electrical, optical, and mechanical properties. This article covers electrochemical biosensors based on MXene nanocomposite for the detection of viruses, along with the associated challenges and future possibilities. Additionally, we highlight various conventional techniques for the detection of infectious agents, discussing their pros and cons. We delve into the challenges faced during the fabrication of MXene-based biosensors and explore future endeavors. It is anticipated that the information presented in this work will pave the way for the development of Point-of-Care (POC) devices capable of sensitive and selective virus detection, enhancing preparedness for ongoing and future pandemics.

A sensitive electrochemical biosensor for detection of carbaryl based on hollow covalent-organic frameworks-gold nanoparticles nanospheres

Carbaryl as an important insecticide is always used in agricultures to achieve higher yields. So, rapid detection of carbaryl residues in agricultural products is very necessary due to its potential harm to human beings. Herein, a hollow covalent-organic frameworks (HCOFTFPB-DBD) gold nanoparticles (AuNPs) nanospheres was used to construct a sensitive electrochemical carbaryl biosensor. The surface of electrode modified by HCOFTFPB-DBD-AuNPs nanospheres was negatively charged and repelled the [Fe(CN)6]3-/4-. The acetylcholinesterase (AChE) immobilized on HCOFTFPB-DBD-AuNPs nanospheres catalyzed the hydrolysis of acetylcholine chloride to thiocholine (TCh). The obtained positively charged TCh was adsorbed on the electrode surface by Au-S, which made the electrode surface positively charged to adsorb the negatively charged [Fe(CN)6]3-/4-, showing enhanced oxidation current of [Fe(CN)6]3-/4-. After carbaryl was added, the oxidation current of [Fe(CN)6]3-/4- deceased because ChE activity were inhibited by carbaryl. So, the sensitive detection of carbaryl was achieved at a low potential, which resulted in a high selectivity. The biosensor had a detection limit of 0.38 μM, a linear range of 1.10 μM-40.0 μM, a sensitivity of 0.00863 mA μM−1 and better performance in actual sample.

Designing and evaluation of a novel electrochemical biosensor based on carbon quantum dots and gold core-shell to detect and measure Human T-lymphotropic Virus-1 (HTLV-1) in clinical samples

The objective of this investigation is to introduce an innovative electrochemical biosensor that can swiftly detect HTLV-1 DNA targets without the need for nucleic acid amplification. The biosensor is equipped with a highly precise antisense DNA oligonucleotide. Additionally, we introduce a new core–shell material, CQDs@AuNPs, for the surface modification of glassy carbon electrodes. L-Cysteine is utilized as a conductive bridge to enhance the binding capabilities, electron transfer efficiency, and conductivity. The biosensor incorporates methylene blue (MB) as an electrochemical indicator with differential pulse voltammetry (DPV) technique, facilitating swift detection within a mere 20 min. Furthermore, it has been able to attain a detection limit of 0.7 aM and quantitation limit of 6 copies/µL with an impressive linear range spanning from 10 aM to 100 nM that displays a positive slope along with exhibiting a remarkably high correlation coefficient measuring at approximately 0.99.We tested the biosensor using 40 HTLV-1 DNA real clinical samples, comprising 30 positive and 10 negative samples, as determined by standard RT-PCR. The biosensor demonstrated a specificity of 96.67% and an exceptional sensitivity of 100%. Rigorous quantitative analysis and statistical techniques, including t-tests, cutoff value determination, receiver operating characteristic curves, and box diagrams, clearly differentiated between the positive and negative groups. These findings underscore the potential of our innovative biosensor as a rapid, precise, and cost-effective tool for early detection of HTLV-1, which holds promise for efficient management and control of the virus.

Expression of Concern: Advances in layered double hydroxide based labels for signal amplification in ultrasensitive electrochemical and optical affinity biosensors of glucose

Expression of Concern: Advances in layered double hydroxide based labels for signal amplification in ultrasensitive electrochemical and optical affinity biosensors of glucose

Development of a highly sensitive non-enzymatic electrochemical cholesterol biosensor based on Ag with Cu2O nanomaterial deposited on TiO2 nanotubes

We developed a highly sensitive non-enzymatic biosensor based on hybrid Ag-Cu2O@TNTs nanostructure aggregate for the detection of cholesterol. A facile anodization process on a thin titanium alloy (Ti6Al4V) plate was achieved to deposit TiO2 nanotubes (TNTs). Subsequently, TNTs was decorated with Cu2O nanomaterials (NM) using wet chemical bath deposition (CBD) technique. The electro-deposition of silver (Ag) nanoparticles on Cu2O@TNTs hybrid aggregate produced high electroactive surface area which enhanced the electron transfer rate. The structure of Ag-Cu2O@TNTs was examined using X-ray diffraction (XRD), transmission emission microscopy (TEM), and field emission scanning electron microscopy (FE-SEM). Cyclic voltammetry (CV) and amperometry techniques were utilized to study the electrochemical behaviour of nanostructures. The hybrid nanostructure demonstrated great sensitivity (12140.06 μAmM−1cm−2) compared to pure TNTs and Cu2O@TNTs with low detection limit (0.057 mM) and fast response. This study highlights exciting potential of nanocomposites in advancement of reproducible and selective biosensor applications.

Target-induced activation of dual DNAzyme recycling amplifications for sensitive electrochemical fat mass and obesity-associated protein assay

The fat mass and obesity-associated protein (FTO) is vital for modulating dynamic reversible process of N6-methyladenosine (m6A) level in the nucleus and the abnormal expression of FTO correlates with generation and development of Alzheimer's disease, obesity and several cancers. The sensitive detection of FTO is therefore of significance for diagnosis of FTO-related diseases. In this work, on the basis of the demethylation enzyme capability of FTO and the dual Mg2+-dependent DNAzyme recycled signal magnification strategy, establishment of a highly sensitive electrochemical FTO biosensor is described. The target FTO molecules catalyze the demethylation of m6A-modifed sequences to form effective cleavage substrates for the MboI endonuclease, leading to the release of active DNAzyme sequences to trigger subsequent dual DNAzyme recycling cycles. Many methylene blue-tagged ssDNA sequences can thus be yielded via the DNAzyme amplifications and captured on the sensor electrode to generate highly amplified currents for detecting FTO in range of 0.04 pM to 10nM with 6.11 fM detection limit. Additionally, the sensor demonstrates high selectivity and is able to be used for detecting cell lysate FTO, showing its potential for the diagnosis and study of FTO-related diseases for various application purposes.

Ultrasensitive detection of PSA in human serum using Label-Free electrochemical biosensor with magnetically induced Self-Assembly based on α-Fe2O3/Fe3O4@Au nanocomposites

To achieve the goals of early diagnosis, screening, and precision medicine for prostate cancer, this research designed a label-free electrochemical biosensor by combining magnetic probes (PSAA/α-Fe2O3/Fe3O4@Au) with magnetically induced self-assembly (MISA) technology to explore the application of prostate-specific antigen (PSA) in precise detection. Magnetic α-Fe2O3/Fe3O4 nanoparticles (NPs) were constructed using a hydrothermal-calcination reduction method. Subsequently, α-Fe2O3/Fe3O4@Au nanocomposites were prepared by reducing HAuCl4 with NaBH4 at a low temperature. The self-assembly method was adopted in two steps: firstly, the sulfhydryl-modified PSA aptamer is immobilized onto the material surface using Au–S bonds; secondly, the magnetic NPs and magnetic glassy carbon electrode (MGCE) undergo self-assembly. The biosensor showed good linear response in the range of 100 fg/mL to 100 ng/mL, with a detection limit of 0.78 pg/mL (S/N = 3) under optimal conditions. Repeatability, stability, selectivity, reproducibility, and the capability to analyze real samples were also investigated. With its cost-effectiveness, operational simplicity, and speed of analysis, the biosensing system platform holds great potential as a valuable tool in clinical PSA detection for point-of-care testing (POCT).

A Single Electrochemical Biosensor Designed to Detect Any Virus.

Viruses are the primary cause of many infectious diseases in both humans and animals. Various testing methods require an amplification step of the viral RNA sample before detection, with quantitative reverse transcription polymerase chain reaction (RT-qPCR) being one of the most widely used along with lesser-known methods like Nucleic Acid Sequence-Based Amplification (NASBA). NASBA offers several advantages, such as isothermal amplification and high selectivity for specific sequences, making it an attractive option for low-income facilities. In this research, we employed a single electrochemical biosensor (E-Biosensor) designed for potentially detecting any virus by modifying the NASBA protocol. In this modified protocol, a reverse primer is designed with an additional 22-nucleotide sequence (tag region) at the 5'-end, which is added to the NASBA process. This tag region becomes part of the final amplicon generated by NASBA. It can hybridize with a single specific E-Biosensor probe set, enabling subsequent virus detection. Using this approach, we successfully detected three different viruses with a single E-Biosensor design, demonstrating the platform's potential for virus detection.

Application of NiFe2O4 nanoparticles towards the detection of ovarian cancer marker

In this work, we explored the potential application of NiFe2O4 magnetic nanoparticles in sensing platforms due to their cost-effectiveness and good magnetic properties. The spinel-type metal oxide was prepared using the conventional hydrothermal synthesis method. The structural, morphological, and magnetic properties of the as-synthesized NiFe2O4 nanoparticles were discussed. The nanoparticles were functionalized with cystamine, glutaraldehyde, and PVDF and then modified with the CA 125 antibody to obtain the immunosensor. FTIR and electrochemical analyses reveal immobilization of the antibody on the surface of the NiFe2O4 magnetic nanoparticles. The immunosensor developed in this work was made on a printed circuit board, allowing it to be used as a point-of-care device. The immunosensor showed excellent stability, reproducibility, specificity, and selectivity. Our findings are of great significance for developing novel, high-performance point-of-care electrochemical biosensors to be applied in detecting the CA 125 antigen, a widely used biomarker for the prognosis of ovarian cancer.