Detection of rare CTCs by electrochemical biosensor built on quaternary PdPtCuRu nanospheres with mesoporous architectures

An integrated electrochemical immunosensor based on Pd-Ir cubic nanozyme and Ketjen black for ultrasensitive detection of circulating tumor cells

Ultrasensitive detection of circulating tumor cells (CTCs) holds significant clinical importance in monitoring metastasis and therapeutic outcomes. In this study, we have developed a novel electrochemical sensing model based on nanomaterials for highly sensitive and specific determination of CTCs. A gold electrode co-modified with Ketjin black (KB) and Au nanoparticles (AuNPs) exhibits exceptional conductivity. By conjugating palladium-iridium cubic nanozyme (Pd-Ir CNE) with antibodies, we have created a detection probe capable of catalyzing hydrogen peroxide (H2O2), thereby amplifying the output signal and resulting in significantly enhanced current on the electrode for detecting CTCs. The constructed immunosensor has achieved a detection limit of 2 cell mL-1 for model MCF-7 cells. Furthermore, the as-constructed electrochemical immunosensor can accurately detect whole blood-spiked target CTCs, showing great promise for clinical applications in early cancer diagnosis and prognosis.

Application of microfluidic technology based on surface-enhanced Raman scattering in cancer biomarker detection: A review

With the continuous discovery and research of predictive cancer-related biomarkers, liquid biopsy shows great potential in cancer diagnosis. Surface-enhanced Raman scattering (SERS) and microfluidic technology have received much attention among the various cancer biomarker detection methods. The former has ultrahigh detection sensitivity and can provide a unique fingerprint. In contrast, the latter has the characteristics of miniaturization and integration, which can realize accurate control of the detection samples and high-throughput detection through design. Both have the potential for point-of-care testing (POCT), and their combination (lab-on-a-chip SERS (LoC-SERS)) shows good compatibility. In this paper, the basic situation of circulating proteins, circulating tumor cells, exosomes, circulating tumor DNA (ctDNA), and microRNA (miRNA) in the diagnosis of various cancers is reviewed, and the detection research of these biomarkers by the LoC-SERS platform in recent years is described in detail. At the same time, the challenges and future development of the platform are discussed at the end of the review. Summarizing the current technology is expected to provide a reference for scholars engaged in related work and interested in this field.

MnO2 nanosheets and gold nanoparticles supported electrochemical detection of circulating tumor cells

The concentration of circulating tumor cells (CTCs) in peripheral blood is strongly correlated with the progress of certain metastatic cancers. In this study, we have developed a novel and facile electrochemical biosensor for the detection of CTCs based on the use of manganese dioxide nanosheets (MnO2 NSs) and gold nanoparticles (AuNPs). Aptamer sequence of target cell is modified on the surface of AuNPs for specifical recognition. With low-speed centrifugation, numerous AuNPs@DNA can be removed from the supernatant. On the other hand, MnO2 NSs are modified on the electrode surface to capture unreacted AuNPs@DNA. The declined electrochemical signal intensity can be used to reflect the level of CTCs. This biosensor achieves a wide linear range from 10 to 104 cells mL-1 and a limit of detection as low as 3 cells mL-1. Due to the specific aptamer as the recognition element, interfering cells can be successfully distinguished and this method performs satisfactorily in clinical samples. Therefore, it has great potential to be used as a powerful tool benefiting rare cells analysis and the investigation of dynamics of cellular interactions.

A Comprehensive Review on Electrochemical Nano Biosensors for Precise Detection of Blood-Based Oncomarkers in Breast Cancer

Breast cancer (BC), one of the most common and life-threatening cancers, has the highest incidence rate among women. Early diagnosis of BC oncomarkers is considered the most effective strategy for detecting and treating BC. Finding the type and stage of BC in women as soon as possible is one of the greatest ways to stop its incidence and negative effects on medical treatment. The development of biosensors for early, sensitive, and selective detection of oncomarkers has recently attracted much attention. An electrochemical nano biosensor (EN) is a very suitable option for a powerful tool for cancer diagnosis. This comprehensive review provides information about the prevalence and pathobiology of BC, recent advances in clinically available BC oncomarkers, and the most common electrochemical nano biosensors for point-of-care (POC) detection of various BC oncomarkers using nanomaterial-based signal amplification techniques.

H-rGO-Pd NPs Nanozyme Enhanced Silver Deposition Strategy for Electrochemical Detection of Glypican-3

Glypican-3 (GPC3), as an emerging biomarker, has been shown to be beneficial for the early diagnosis and treatment of hepatocellular carcinoma (HCC). In this study, an ultrasensitive electrochemical biosensor for GPC3 detection has been constructed based on the hemin-reduced graphene oxide-palladium nanoparticles (H-rGO-Pd NPs) nanozyme-enhanced silver deposition signal amplification strategy. When GPC3 specifically interacted with GPC3 antibody (GPC3_Ab) and GPC3 aptamer (GPC3_Apt), an "H-rGO-Pd NPs-GPC3_Apt/GPC3/GPC3_Ab" sandwich complex was formed with peroxidase-like properties which enhanced H₂O₂ to reduce the silver (Ag) ions in solution to metallic Ag, resulting in the deposition of silver nanoparticles (Ag NPs) on the surface of the biosensor. The amount of deposited Ag, which was derived from the amount of GPC3, was quantified by the differential pulse voltammetry (DPV) method. Under ideal circumstances, the response value was linearly correlated with GPC3 concentration at 10.0-100.0 μg/mL with R² of 0.9715. When the GPC3 concentration was in the range from 0.01 to 10.0 μg/mL, the response value was logarithmically linear with the GPC3 concentration with R² of 0.9941. The limit of detection was 3.30 ng/mL at a signal-to-noise ratio of three and the sensitivity was 1.535 μAμM^-1cm^-2. Furthermore, the electrochemical biosensor detected the GPC3 level in actual serum samples with good recoveries (103.78-106.52%) and satisfactory relative standard deviations (RSDs) (1.89-8.81%), which confirmed the applicability of the sensor in practical applications. This study provides a new analytical method for measuring the level of GPC3 in the early diagnosis of HCC.

Tailored point-of-care biosensors for liquid biopsy in the field of oncology

In the field of cancer detection, technologies to analyze tumors using biomarkers circulating in fluids such as blood have developed rapidly based on liquid biopsy. A proactive approach to early cancer detection can lead to more effective treatments with minimal side effects and better long-term patient survival. However, early detection of cancer is hindered by the existing limitations of conventional cancer diagnostic methods. To enable early diagnosis and regular monitoring and improve automation, the development of integrated point-of-care (POC) and biosensors is needed. This is expected to fundamentally change the diagnosis, management, and monitoring of response to treatment of cancer. POC-based techniques will provide a way to avoid complications that occur after invasive tissue biopsy, such as bleeding, infection, and pain. The aim of this study is to provide a comprehensive view of biosensors and their clinical relevance in oncology for the detection of biomarkers with liquid biopsies of proteins, miRNA, ctDNA, exosomes, and cancer cells. The preceding discussion also illustrates the changing landscape of liquid biopsy-based cancer diagnosis through nanomaterials, machine learning, artificial intelligence, wearable devices, and sensors, many of which apply POC design principles. With the advent of sensitive, selective, and timely detection of cancer, we see the field of POC technology for cancer detection and treatment undergoing a positive paradigm shift in the foreseeable future.