Exosomes are highly important in clinical diagnosis due to their high homology with their parental cells. However, conventional exosome detection methods still face the challenges of expensive equipment, low sensitivity, and complex procedures. Field effect transistors (FETs) are not only the most essential electronic component in the modern microelectronics industry but also show great potential for biomolecule detection owing to the advantages of rapid response, high sensitivity, and label-free detection. In this study, we proposed a Si nanowire field-effect transistor (Si-NW Bio-FET) device chemically modified with specific antibodies for the electrical and label-free detection of exosomes. The Si-NW FETs were fabricated by standard microelectronic processes with 45 nm width nanowires and packaged in a polydimethylsiloxane (PDMS) microfluidic channel. The nanowires were further modified with the specific CD63 antibody to form a Si-NW Bio-FET. The use of the developed Si-NW Bio-FET for the electrical and label-free detection of exosomes was successfully demonstrated with a limit of detection (LOD) of 2159 particles/mL. In contrast to other technologies, in this study, Si-NW Bio-FET provides a unique strategy for directly quantifying and real-time detecting exosomes without labeling, indicating its potential as a tool for the early diagnosis of cancer.

Tumor-derived exosomes have been recognized as potential biomarkers for cancer diagnosis because they are actively involved in cancer progression and metastasis. However, progress in practical exosome analysis is still slow due to the limitation in exosome isolation and detection. The development of microfluidic devices has provided a promising analytical platform compared with traditional methods. In this study, we develop an exosome isolation and detection method based on a microfluidic device (ExoDEP-chip), which realized microsphere mediated dielectrophoretic isolation and immunoaffinity detection. Exosomes were firstly isolated by binding to antibodies pre-immobilized on the polystyrene (PS) microsphere surface and were further detected using fluorescently labeled antibodies by fluorescence microscopy. Single microspheres were then trapped into single microwells under the DEP force in the ExoDEP-chip. A wide range from 1.4 × 10³ to 1.4 × 10⁸ exosomes per mL with a detection limit of 193 exosomes per mL was obtained. Through monitoring five proteins (CD81, CEA, EpCAM, CD147, and AFP) of exosomes from three different cell lines (A549, HEK293, and HepG2), a significant difference in marker expression levels was observed in different cell lines. Therefore, this method has good prospects in exosome-based tumor marker detection and cancer diagnosis.

Flexible humidity sensors, as pivotal sensing components in the Internet of Things and intelligent era, have achieved significant progress in material innovation, fabrication engineering, and application diversification in recent years. This review systematically presents the current research status of flexible humidity sensors, focusing on the influence of novel humidity-sensitive materials(including polymers, metal oxides, carbon-based materials, and two-dimensional materials) on key performance metrics such as sensitivity, response time, and stability. The optimization effects of fabrication technologies such as screen printing, spraying, and deposition on device performance are also analyzed. Furthermore, the innovative applications of flexible humidity sensors in fields including healthcare, smart agriculture, smart homes, and human-machine interaction are elaborated in detail. These applications highlight the sensors’ adaptability to diverse environmental requirements and their potential to enable intelligent monitoring and interactive systems. Finally, future technological directions for flexible humidity sensors are proposed from the perspectives of material system innovation, improvement of multi-parameter collaborative sensing performance, and optimization of adaptability to complex environments. The proposed development directions are targeted at achieving higher precision, multifunctionality, and self-powered operation, providing insights and guidance for the research and development of next-generation flexible intelligent sensing devices. By bridging material science, manufacturing engineering, and application engineering, this comprehensive review provides a forward-looking perspective on advancing flexible humidity sensing technologies for emerging intelligent systems.

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.