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Timely identification of cancers is pivotal in optimizing treatment efficacy and reducing their widespread impact. This study introduces a novel biosensor for the sensitive electrochemical detection of cancer cells overexpressing mucin 1 (MUC1), a well-established model for breast cancer. The sensor substrate comprises gold columnar nanostructures obtained through glancing angle deposition (GLAD) of copper nanostructures, subsequently replaced by gold via a facile galvanic replacement process. Functionalizing these gold nanostructures with aptamers targeting the MUC1 glycoproteins, a prominent cancer biomarker, enables specific recognition of MCF-7 breast cancer cells. The proposed electrochemical sensing platform offers several advantages, including high selectivity, a wide linear range of detection, a low detection limit of 30 cells per mL, and long-term stability, rendering this sensor highly desirable for definitive breast cancer diagnosis.

We present an advanced electrochemical immunosensor designed to detect the vascular endothelial growth factor (VEGF) precisely. The sensor is constructed on a modified porous gold electrode through a fabrication process involving the deposition of silver and gold on an FTO substrate. Employing thermal annealing and a de-alloying process, the silver is eliminated from the electrode, producing a reproducible porous gold substrate. Utilizing a well-defined protocol, we immobilize the heavy-chain (VHH) antibody against VEGF on the gold substrate, facilitating VEGF detection through various electrochemical methods. Remarkably, this immunosensor performs well, featuring an impressive detection limit of 0.05 pg/mL and an extensive linear range from 0.1 pg/mL to 0.1 µg/mL. This emphasizes it's to measure biomarkers across a wide concentration spectrum precisely. The robust fabrication methodology in this research underscores its potential for widespread application, offering enhanced precision, reproducibility, and remarkable detection capabilities for the developed immunosensor., (© 2024. The Author(s).)

Lung cancer is one of the deadliest cancers worldwide due to the inability of existing methods for early diagnosis. Tumor-derived exosomes are nano-scale vesicles released from tumor cells to the extracellular environment, and their investigation can be very useful in both biomarkers for early cancer screening and treatment assessment. This research detected the exosomes via an ultrasensitive electrochemical biosensor containing gold nano-islands (Au-NIs) structures. This way, a high surface-area-to-volume ratio of nanostructures was embellished on the FTO electrodes to increase the chance of immobilizing the CD-151 antibody. In this way, a layer of gold was first deposited on the electrode by physical vapor deposition (PVD), followed by thermal annealing to construct primary gold seeds on the surface of the electrode. Then, gold seeds were grown by electrochemical deposition through gold salt. The cell-derived exosomes were successfully immobilized on the FTO electrode through the CD-151 antibody, and cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods were used in this research. In the CV method, the change in the current passing through the working electrode is measured so that the connection of exosomes causes the current to decrease. In the EIS method, surface resistance changes were investigated so that the binding of exosomes increased the surface resistance. Various concentrations of exosomes in both cell culture and blood serum samples were measured to test the sensitivity of the biosensor, which makes our biosensor capable of detecting 20 exosomes per milliliter.

The development of an electrochemical aptasensor for the detection of CA125 as an ovarian cancer biomarker using gold nanostructures (GNs) modified electrodes is reported. The GNs were deposited on the surface of fluorine-doped tin oxide electrodes using a simple electrochemical method and the effects of pH and surfactant concentration on the topography and electrochemical properties of the resulting GNs modified electrodes were investigated. The electrodes were characterized using field-emission scanning electron microscopy and X-ray diffraction, cyclic voltammetry, and electrochemical impedance spectroscopy. The best electrode, in terms of the uniformity of the deposited GNs and the increase in electroactive surface area, was used for development of an aptasensor for CA125 tumor marker detection in human serum. Signal amplification was done by using aptamer-conjugated gold nanorods resulting in the detection limit of 2.6 U/ml and a linear range of 10 to 800 U/ml. The results showed that without the need for expensive antibodies, the developed aptasensor could specifically measure the clinically relevant concentrations of the tumor marker in human serum., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

The core-shell non-enzymatic glucose sensors are generally fabricated by chemical synthesis approaches followed by a binder-based immobilization process. Here, we have introduced a new approach to directly synthesis the core-shell of Au@Cu and its Au@Cu x O oxides on an FTO electrode for non-enzymatic glucose detection. Physical vapor deposition of Au thin film followed by thermal annealing has been used to fabricate Au nanocores on the electrode. The Cu shells have been deposited selectively on the Au cores using an electrodeposition method. Additionally, Au@Cu 2 O and Au@CuO have been synthesized via post thermal annealing of the Au@Cu electrode. This binder-free and selective-growing approach has the merit of high electrooxidation activity owing to improving electron transfer ability and providing more active sites on the surface. Electrochemical measurements indicate the superior activity of the Au@Cu 2 O electrode for glucose oxidation. The high sensitivity of 1601 μAcm -2  mM -1 and a low detection limit of 0.6 μM are achieved for the superior electrode. Additionally, the sensor indicates remarkable reproducibility and supplies accurate results for glucose detection in human serums. Moreover, this synthesis approach can be used for fast, highly controllable and precise fabrication of many core-shell structures by adjusting the electrochemical deposition and thermal treatment parameters., (© 2022. The Author(s).)