An electrochemical immunosensing method for detecting melanoma cells

Biosensors for melanoma skin cancer diagnostics

Skin cancer is a critical global public health concern, with melanoma being the deadliest variant, correlated to 80% of skin cancer-related deaths and a remarkable propensity to metastasize. Despite notable progress in skin cancer prevention and diagnosis, the limitations of existing methods accentuate the demand for precise diagnostic tools. Biosensors have emerged as valuable clinical tools, enabling rapid and reliable point-of-care (POC) testing of skin cancer. This review offers insights into skin cancer development, highlights essential cutaneous melanoma biomarkers, and assesses the current landscape of biosensing technologies for diagnosis. The comprehensive analysis in this review underscores the transformative potential of biosensors in revolutionizing melanoma skin cancer diagnosis, emphasizing their critical role in advancing patient outcomes and healthcare efficiency. The increasing availability of these approaches supports direct diagnosis and aims to reduce the reliance on biopsies, enhancing POC diagnosis. Recent advancements in biosensors for skin cancer diagnosis hold great promise, with their integration into healthcare expected to enhance early detection accuracy and reliability, thereby mitigating socioeconomic disparities.

Electrochemical Biosensors for Whole Blood Analysis: Recent Progress, Challenges, and Future Perspectives

Whole blood, as one of the most significant biological fluids, provides critical information for health management and disease monitoring. Over the past 10 years, advances in nanotechnology, microfluidics, and biomarker research have spurred the development of powerful miniaturized diagnostic systems for whole blood testing toward the goal of disease monitoring and treatment. Among the techniques employed for whole-blood diagnostics, electrochemical biosensors, as known to be rapid, sensitive, capable of miniaturization, reagentless and washing free, become a class of emerging technology to achieve the target detection specifically and directly in complex media, e.g., whole blood or even in the living body. Here we are aiming to provide a comprehensive review to summarize advances over the past decade in the development of electrochemical sensors for whole blood analysis. Further, we address the remaining challenges and opportunities to integrate electrochemical sensing platforms.

Synthesis and Preclinical Evaluation of a 68Ga-Labeled Pyridine-Based Benzamide Dimer for Malignant Melanoma Imaging

Benzamide (BZA), a small molecule that can freely cross cell membranes and bind to melanin, has served as an effective targeting group for melanoma theranostics. In this study, a novel pyridine-based BZA dimer (denoted as H-2) was labeled with ⁶⁸Ga ([⁶⁸Ga]Ga-H-2) for positron emission tomography (PET) imaging of malignant melanomas. [⁶⁸Ga]Ga-H-2 was obtained with high radiochemical yield (98.0 ± 2.0%) and satisfactory radiochemical purity (>95.0%). The specificity and affinity of [⁶⁸Ga]Ga-H-2 were confirmed in melanoma B16F10 cells and in vivo PET imaging of multiple tumor models (B16F10 tumors, A375 melanoma, and lung metastases). Monomeric [⁶⁸Ga]Ga-H-1 was prepared as a control radiotracer to verify the effects of the molecular structure on pharmacokinetics. The values of the lipid-water partition coefficient of [⁶⁸Ga]Ga-H-2 and [⁶⁸Ga]Ga-H-1 demonstrated hydrophilicity with log P = -2.37 ± 0.07 and -2.02 ± 0.09, respectively. PET imaging and biodistribution showed a higher uptake of [⁶⁸Ga]Ga-H-2 in B16F10 primary and metastatic melanomas than that in A375 melanomas. However, the relatively low uptake of monomeric [⁶⁸Ga]Ga-H-1 in B16F10 tumors and high accumulation in nontarget organs resulted in poor PET imaging quality. This study demonstrates the synthesis and preclinical evaluation of the novel pyridine-based BZA dimer [⁶⁸Ga]Ga-H-2 and indicates that the dimer tracer has promising applications in malignant melanoma-specific PET imaging because of its high uptake and long-time retention in malignant melanoma.

Biomimetic Nanoscale Materials for Skin Cancer Therapy and Detection

Skin cancer has developed as one of the most common types of cancer in the world, with a significant impact on public health impact and the economy. Nanotechnology methods for cancer treatment are appealing since they allow for the effective transport of medicines and other biologically active substances to specific tissues while minimizing harmful consequences. It is one of the most significant fields of research for treating skin cancer. Various nanomaterials have been employed in skin cancer therapy. The current review will summarize numerous methods of treating and diagnosing skin cancer in the earliest stages. There are numerous skin cancer indicators available for the prompt diagnosis of this type of disease. Traditional approaches to skin cancer diagnosis are explored, as are their shortcomings. Electrochemical and optical biosensors for skin cancer diagnosis and management were also discussed. Finally, various difficulties concerning the cost and ease of use of innovative methods should be addressed and overcome.

Electrochemical sensing technology for liquid biopsy of circulating tumor cells-a review

In recent years, a lot of new detection techniques for circulating tumor cells (CTCs) have been developed. Among them, electrochemical sensing technology has gradually developed because of its advantages of good selectivity, high sensitivity, low cost and rapid detection. Especially in the latest decade, the field of electrochemical biosensing has witnessed great progress, thanks to the merging of biosensing research area with nanotechnology, immunotechnology, nucleic acid technology, and microfluidic technology. In this review, the recent progress for the detection of CTCs according to the principle of detection was summarized and how they can contribute to the enhanced performance of such biosensors was explained. The latest electrode construction strategies such as rolling circle amplification reaction, DNA walker and microfluidic technology and their advantages were also introduced emphatically. Moreover, the main reasonswhy the existing biosensors have not been widely used clinically and the next research points were clearly put forward.

Magnetic bead-based electrochemical and colorimetric assays of circulating tumor cells with boronic acid derivatives as the recognition elements and signal probes

Simple, sensitive and rapid detection of circulating tumor cells (CTCs) is of great importance for early diagnosis and therapy of cancers. Overexpression of sugar units on cell surface is related to the phenotypes of many cancers. Based on the boronate ester interaction, we reported the electrochemical and colorimetric detection of CTCs with high simplicity and sensitivity. Specifically, ferroceneboronic acid (FcBA) can be measured by differential pulse voltammetry and 4-mercaptophenylboronic acid (MPBA) can induce the aggregation and color change of gold nanoparticles (AuNPs). CTCs captured by the aptamer-modified magnetic beads (Apt-MBs) can sequestrate FcBA or MPBA molecules by the formation of boronate ester bonds, thus leading to the decrease in the electrochemical signal of FcBA or preventing the MPBA-triggered aggregation of AuNPs. Due to the overexpression of sugar groups on the surface of CTCs, the amplification-free methods exhibited high sensitivity and obviated the use of additional antibody or aptamer for the recognition of captured cells. With MCF-7 cancer cell as the model, 50 cells can be readily determined by the electrochemical and colorimetric methods. The proposed strategy is valuable for probing of cell glycosylation and designing of novel sensing devices for detection of sugar-containing biological macromolecules and cells.

A flow-through microfluidic system for the detection of circulating melanoma cells

We report the fabrication of polyaniline nanofiber (PANI)-modified screen-printed electrode (PANI/SPE) incorporated in a poly-dimethylsiloxane (PDMS) microfluidic channel for the detection of circulating tumor cells. We employed this device to detect melanoma skin cancer cells through specific immunogenic binding of cell surface biomarker melanocortin 1 receptor (MC1R) to anti-MC1R antibody. The antibody-functionalized PANI/SPE was used in batch-continuous flow-through fashion. An aqueous cell suspension of ferri/ferrocyanide at a flow rate of 1.5 mL/min was passed over the immunosensor, which allowed for continuous electrochemical measurements. The sensor performed exceptionally well affording an ultralow limit of quantification of 1 melanoma cell/mL, both in buffer and when mixed with peripheral blood mononuclear cells, and the response was log-linear over the range of 10-9000 melanoma cells/10 mL.

Ultrasensitive label-free detection of circulating tumor cells using conductivity matching of two-dimensional semiconductor with cancer cell

The excellent conductivity matching of two-dimensional (2D) semiconductor nanomaterials (e.g. MoS₂) with cancer cell plays an important role in ultrasensitive label-free impedimetric detection of circulating tumor cells (CTC) (<1 cell/mL). Firstly, 2D semiconductor materials (e.g. 2D MoS₂) exfoliated by folic acid (FA) is used to construct MoS₂/FA-modified gold electrode (AuE/MoS₂/FA). Then, the fabricated electrode is applied for HeLa cell detection in a linear range from 1 to 10⁵ cell/mL with a detection limit of 0.43 cell/mL (S/N = 3). The detection mechanism of high sensitivity might be owing to the electric conductivity matching of MoS₂ (0.14 S/m) to cancer cell (0.13-0.23 S/m). A negligible conductivity change induced by cancer cell will produce a large impedance change of semiconductor electrode. Furthermore, HeLa cells dispersed in healthy blood samples are detected by suggested cytosensor in a linear range from 50 to 10⁵ cell/mL with a detection limit of 52.24 cell/mL (S/N = 2). Finally, we demonstrate that the cytosensor is capable of differentiating patients of cervical and liver cancers by the real CTC analysis from healthy control.

A novel hydrosoluble near-infrared fluorescent probe for specifically monitoring tyrosinase and application in a mouse model

A novel hydrosoluble near-infrared fluorescent probe is applied to imaging and detection of endogenous tyrosinase in living cells, zebrafish and a mouse model.

Integrating Electrochemical Immunosensing and Cell Adhesion Technologies for Cancer Cell Detection and Enumeration

We have successfully integrated techniques for controlling cell adhesion and performing electrochemical differential pulse voltammetry (DPV) through the use of digitally controlled microfluidics and patterned transparent indium tin oxide electrode arrays to enable rapid and sensitive enumeration of cancer cells in a scalable microscale format. This integrated approach leverages a dual-working electrode (WE) surface to improve the specificity of the detection system. Here, one of the WE surfaces is functionalized with anti-Melanocortin 1 Receptor antibodies specific to melanoma cancer cells, while the other WE acts as a control (i.e., without antibody), for detecting non-specific interactions between cells and the electrode. The method is described and shown to provide effective detection of melanoma cells at concentrations ranging between 25 to 300 cells per 20 μL sample volume after a 5 min incubation and 15 s of DPV measurements. The estimated limit of detection was ~17 cells. The sensitivity and specificity of the assay were quantified using addition of large fractions of non-target cells and resulted in a detection reproducibility of ~97%. The proposed approach demonstrates a unique integration of electrochemical sensing and microfluidic cell adhesion technologies with multiple advantages such as label-free detection, short detection times, and low sample volumes. Next steps for this platform include testing with patient samples and use of other cell-surface biomarkers for detection and enumeration of circulating tumor cells in prostate, breast, and colon cancer.

Ultrasensitive electrochemical immunoassay for melanoma cells using mesoporous polyaniline

We report the development of an antibody (anti-MC1R antibody)-functionalized polyaniline nanofibers modified screen-printed electrode capable of efficient electrochemical detection of melanoma cells at levels (1 cell per mL) not readily achieved by other methods. This immunosensor is highly selective in its detection of melanoma cells over normal human cells.

Identification and Quantitation of Circulating Tumor Cells

Circulating tumor cells (CTCs) are shed from the primary tumor into the circulatory system and act as seeds that initiate cancer metastasis to distant sites. CTC enumeration has been shown to have a significant prognostic value as a surrogate marker in various cancers. The widespread clinical utility of CTC tests, however, is still limited due to the inherent rarity and heterogeneity of CTCs, which necessitate robust techniques for their efficient enrichment and detection. Significant recent advances have resulted in technologies with the ability to improve yield and purity of CTC enrichment as well as detection sensitivity. Current efforts are largely focused on the translation and standardization of assays to fully realize the clinical utility of CTCs. In this review, we aim to provide a comprehensive overview of CTC enrichment and detection techniques with an emphasis on novel approaches for rapid quantification of CTCs.

Simultaneous detection of MCF-7 and HepG2 cells in blood by ICP-MS with gold nanoparticles and quantum dots as elemental tags

In this work, we demonstrate a novel method based on inductively coupled plasma mass spectrometry (ICP-MS) detection with gold nanoparticles (Au NPs) and quantum dots (QDs) labeling for the simultaneous counting of two circulating tumor cell lines (MCF-7 and HepG2 cells) in human blood. MCF-7 and HepG2 cells were captured by magnetic beads coupled with anti-EpCAM and then specifically labeled by CdSe QDs-anti-ASGPR and Au NPs-anti-MUC1, respectively, which were used as signal probes for ICP-MS measurement. Under the optimal experimental conditions, the limits of detection of 50 MCF-7, 89 HepG2 cells and the linear ranges of 200-40000 MCF-7, 300-30000 HepG2 cells were obtained, and the relative standard deviations for seven replicate detections of 800 MCF-7 and HepG2 cells were 4.6% and 5.7%, respectively. This method has the advantages of high sensitivity, low sample consumption, wide linear range and can be extended to the simultaneous detection of multiple CTC lines in human peripheral blood.

From mercury to nanosensors: Past, present and the future perspective of electrochemistry in pharmaceutical and biomedical analysis

Polarography was the first developed automated method of voltage-controlled electrolysis with dropping mercury electrode (DME). Then, hanging mercury drop and static mercury drop electrodes were added as an alternative indicator electrode. In this way, polarography turned formally into voltammetry with mercury electrodes in the electroreduction way. Solid electrodes such as noble metal and carbon based electrodes can be used for the investigation of the compounds for both oxidation and reduction directions, which is called voltammetry. The voltammetric and polarographic techniques are more sensitive, reproducible, and easily used electroanalytical methods that can be alternative to more frequently used separation and spectrometric methods. Furthermore, in some cases there is a relationship between voltammetry and pharmaceutical samples, and the knowledge of the mechanism of their electrode reactions can give a useful clue in elucidation of the mechanism of their interaction with living cells. The voltammetric and polarographic analysis of drugs in pharmaceutical preparations are by far the most common use of electrochemistry for analytical pharmaceutical problems. Recent trends and challenges in the electrochemical methods for the detection of DNA hybridization and pathogens are available. Low cost, small sample requirement and possibility of miniaturization justifies their increasing development.