Circulating tumor cells (CTCs), a type of cancer cell that spreads from primary tumors into human peripheral blood and are considered as a new biomarker of cancer liquid biopsy. It provides the direction for understanding the biology of cancer metastasis and progression. Isolation and analysis of CTCs offer the possibility for early cancer detection and dynamic prognosis monitoring. The extremely low quantity and high heterogeneity of CTCs are the major challenges for the application of CTCs in liquid biopsy. There have been significant research endeavors to develop efficient and reliable approaches to CTC isolation and analysis in the past few decades. With the advancement of microfabrication and nanomaterials, a variety of approaches have now emerged for CTC isolation and analysis on microfluidic platforms combined with nanotechnology. These new approaches show advantages in terms of cell capture efficiency, purity, detection sensitivity and specificity. This review focuses on recent progress in the field of nanotechnology-assisted microfluidics for CTC isolation and detection. Firstly, CTC isolation approaches using nanomaterial-based microfluidic devices are summarized and discussed. The different strategies for CTC release from the devices are specifically outlined. In addition, existing nanotechnology-assisted methods for CTC downstream analysis are summarized. Some perspectives are discussed on the challenges of current methods for CTC studies and promising research directions.

Electric cell–substrate impedance sensing exhibits a real-time and label-free feature to monitor the response of cells stimulated by various biochemical and mechanical signals. Alterations in the currents passing through the cell–electrode system characterize the impedance variations of cells. The impedance responses of HeLa cells under distinct chemotherapy drugs combine the effects of cell proliferation and cell–substrate adhesion. Optimal interdigitated electrodes were selected to explore the impedance responses of HeLa cells. Measurements of impedance of cells in response to three widely used chemotherapy drugs in clinical practice, namely cisplatin, doxorubicin, 5-fluorouracil, were performed. The results demonstrated that distinct impedance responses of HeLa cells to drugs were exhibited and a decrease in measured impedance was observed after drug treatment, accompanied by alterations in the distribution and intensity of the adhesion-related protein vinculin and the rate of cell proliferation. The link between the impedance profiles of HeLa cells and their biological functions was developed based on the circuit model. This study demonstrated the weights of cell proliferation and adhesion of HeLa cells under the treatments of DDP, DOX, and 5-FU, resulted in distinct impedance responses of cells, providing an impedance-based evaluation methodology for cervical cancer treatment.

Three‐dimensional nanowire arrays based on different biomaterials have emerged as promising platforms for the studies of cell behaviours over the years. Fabrication of nanosurfaces with complex geometries and controllable morphologies is still a challenge. In this work, nanowire forests (NWFs), which exhibited various aspect ratios, were fabricated using a reactive ion etching technique. Especially, by regulating bombardment periods of oxygen and argon plasma, the aspect ratio of nanowires in NWFs could be decreased from 29:1 to 7:1. Based on superhydrophilicity of the NWFs, the interaction between the NWFs with various aspect ratios and HeLa cells (human cervical carcinoma cell line) after different culturing periods was systematically investigated. NWFs with a low aspect ratio provide appropriate nanosubstrates for the cells, enabling them to grow on and adhere to the surface. NWFs with a high aspect ratio exhibited low mechanical strength under initial cell adhesion, which further hindered cell growth and migration as the incubation time increased. These findings provide essential guidance in designing nanostructure geometries for more efficient capture of circulating tumour cells and manipulation of cytomorphology in future.