Photoelectrochemical biosensing platforms for tumor marker detection

Tumor metastasis is one of the main causes of cancer incidence and death worldwide. In the process of tumor metastasis, the isolation and analysis of circulating tumor cells (CTCs) plays a crucial role in the early diagnosis and prognosis of cancer patients. Due to the rarity and inherent heterogeneity of CTCs, there is an urgent need for reliable CTCs separation and detection methods in order to obtain valuable information on tumor metastasis and progression from CTCs. Microfluidic technology is increasingly used in various studies of CTCs separation, identification and characterization because of its unique advantages, such as low cost, simple operation, less reagent consumption, miniaturization of the system, rapid detection and accurate control. This paper reviews the research progress of microfluidic technology in CTCs separation and detection in recent years, as well as the potential clinical application of CTCs, looks forward to the application prospect of microfluidic technology in the treatment of tumor metastasis, and briefly discusses the development prospect of microfluidic biosensor.

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Application of Microfluidics in Detection of Circulating Tumor Cells

The efficient isolation and specific discrimination of circulating tumor cells (CTCs) is expected to provide valuable information for understanding tumor metastasis and play an important role in the treatment of cancer patients. In this study, we developed a novel and rapid method for efficient capture and specific identification of cancer cells using hyaluronic acid (HA)-modified SiO2-coated magnetic beads in a microfluidic chip. First, polyacrylamide-surfaced SiO2-coated magnetic beads (SiO2@MBs) were covalently conjugated with HA, and the created HA-modified SiO2@MBs (HA-SiO2@MBs) display binding specificity to HeLa cells (a human cervical carcinoma cell line) overexpressing CD44 receptors. After incubating the HA-SiO2@MBs with cancer cells for 1 h, the mixture of MBs and cells was drawn into a designed microfluidic channel with two inlets and outlets. Through the formation of lamellar flow, cells specifically bound with the HA-SiO2@MBs can be separated under an external magnetic field with a capture efficiency of up to 92.0%. The developed method is simple, fast, and promising for CTC separation and cancer diagnostics applications.

Efficient Capture and Separation of Cancer Cells Using Hyaluronic Acid-Modified Magnetic Beads in a Microfluidic Chip.

Photoelectrochemical (PEC) sensor and biosensor are regarded as a hot spot of detection methods which present great potential for future analytical field for various targets. The impetus for the development of Bi2S3-based PEC sensor and biosensor was located the adjustable energy band with various morphologies. In this review, we have discussed the Bi2S3 semiconductor applied in PEC platform for sensing various target molecules. Due to the high recombination efficiency of the photogenerated electron-hole pairs, various strategies have been employed to improve the migration rate of the photogenerated electron, increase the detachment of photogenerated electron-hole pairs and promote the PEC response of Bi2S3, such as element-doping Bi2S3, conductive material modified Bi2S3, Bi2S3-based binary heterojunction, and Bi2S3-based multiple heterojunction, which have been discussed in this work. The challenges against Bi2S3-based PEC and its future prospects will also be explored. 

Recent advances and application of Bi2S3-based composites in photoelectrochemical sensors and biosensors

Technological advancement to enhance tumor cells (TC) has allowed discovery of various cellular bio-markers: cancer stem cells (CSC), circulating tumor cells (CTC), and endothelial progenitor cells (EPC). These are responsible for resistance, metastasis, and premetastatic conditions of cancer. Detection of CSC, CTC, and EPC assists in early diagnosis, recurrence prediction, and treatment efficacy. This review describes various methods to detect TC subpopulations such as in vivo assays (sphere-forming, serial dilution, and serial transplantation), in vitro assays (colony-forming cells, microsphere, side-population, surface antigen staining, aldehyde dehydrogenase activity, and Paul Karl Horan label-retaining cells, surface markers, nonenriched and enriched detection), reporter systems, and other analytical methods (flow cytometry, fluorescence microscopy/spectroscopy, etc.). The detailed information on methods to detect CSC, CTC, and EPC in this review will assist investigators in successful prognosis, diagnosis, and cancer treatment with greater ease.

Jiaju Shi

Papers

Photoelectrochemical biosensing platforms for tumor marker detection

Combination of microfluidic chips and biosensing for the enrichment of circulating tumor cells.

Self-assembly of DNA-hyperbranched aggregates catalyzed by a dual-targets recognition probe for miRNAs SERS detection in single cells.