Background: The electrochemical biosensor is one of the typical sensing devices based on transducing the biochemical events to electrical signals. In this type of sensor, an electrode is a key component that is employed as a solid support for immobilization of biomolecules and electron movement. Thanks to numerous nanomaterials that possess the large surface area, synergic effects are enabled by improving loading capacity and the mass transport of reactants for achieving high performance in terms of analytical sensitivity. Main body: We categorized the current electrochemical biosensors into two groups, carbon-based (carbon nanotubes and graphene) and non-carbon-based nanomaterials (metallic and silica nanoparticles, nanowire, and indium tin oxide, organic materials). The carbon allotropes can be employed as an electrode and supporting scaffolds due to their large active surface area as well as an effective electron transfer rate. We also discussed the non-carbon nanomaterials that are used as alternative supporting components of the electrode for improving the electrochemical properties of biosensors. Conclusion: Although several functional nanomaterials have provided the innovative solid substrate for high performances, developing on-site version of biosensor that meets enough sensitivity along with high reproducibility still remains a challenge. In particular, the matrix interference from real samples which seriously affects the biomolecular interaction still remains the most critical issues that need to be solved for practical aspect in the electrochemical biosensor.

An electrochemical immunosensor employs antibodies as capture and detection means to produce electrical charges for the quantitative analysis of target molecules. This sensor type can be utilized as a miniaturized device for the detection of point-of-care testing (POCT). Achieving high-performance analysis regarding sensitivity has been one of the key issues with developing this type of biosensor system. Many modern nanotechnology efforts allowed for the development of innovative electrochemical biosensors with high sensitivity by employing various nanomaterials that facilitate the electron transfer and carrying capacity of signal tracers in combination with surface modification and bioconjugation techniques. In this review, we introduce novel nanomaterials (e.g., carbon nanotube, graphene, indium tin oxide, nanowire and metallic nanoparticles) in order to construct a high-performance electrode. Also, we describe how to increase the number of signal tracers by employing nanomaterials as carriers and making the polymeric enzyme complex associated with redox cycling for signal amplification. The pros and cons of each method are considered throughout this review. We expect that these reviewed strategies for signal enhancement will be applied to the next versions of lateral-flow paper chromatography and microfluidic immunosensor, which are considered the most practical POCT biosensor platforms.

The liquid biopsy has gained significant attention in cancer diagnostics, with circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) being recognized as key biomarkers for tumor detection and monitoring. However, each biomarker possesses inherent limitations that restrict its standalone clinical utility, such as the rarity and heterogeneity of CTCs and the variable sensitivity and specificity of ctDNA assays. This highlights the necessity of integrating both biomarkers to maximize diagnostic and prognostic potential, offering a more comprehensive understanding of the tumor biology and therapeutic response. In this review, we summarize clinical studies that have explored the combined analysis of CTCs and ctDNA as biomarkers, providing insights into their synergistic value in diverse tumor types. Specifically, this paper examines the individual advantages and limitations of CTCs and ctDNA, details the findings of combined biomarker studies across various cancers, highlights the benefits of dual biomarker approaches over single-biomarker strategies, and discusses future prospects for advancing personalized oncology through liquid biopsies. By offering a comprehensive overview of clinical studies combining CTCs and ctDNA, this review serves as a guideline for researchers and clinicians aiming to enhance biomarker-based strategies in oncology and informs biosensor design for improved biomarker detection.

Mature cardiomyocytes (CMs) obtained from human pluripotent stem cells (hPSCs) have been required for more accurate in vitro modeling of adult-onset cardiac disease and drug discovery. Here, we found that FGF4 and ascorbic acid (AA) induce differentiation of BG01 human embryonic stem cell–cardiogenic mesoderm cells (hESC-CMCs) into mature and ventricular CMs. Co-treatment of BG01 hESC-CMCs with FGF4+AA synergistically induced differentiation into mature and ventricular CMs. FGF4+AA-treated BG01 hESC-CMs robustly released acute myocardial infarction (AMI) biomarkers (cTnI, CK-MB, and myoglobin) into culture medium in response to hypoxic injury. Hypoxia-responsive genes and potential cardiac biomarkers proved in the diagnosis and prognosis of coronary artery diseases were induced in FGF4+AA-treated BG01 hESC-CMs in response to hypoxia based on transcriptome analyses. This study demonstrates that it is feasible to model hypoxic stress in vitro using hESC-CMs matured by soluble factors.

Exosomes emerges as indicators of the tumor microenvironment, yet their predictive utility for immunotherapy responses is limited by the insufficient sensitivity and specificity of currently available assays. Here, a multi‐level engineering strategy is presented that enables accurate exosome‐based prediction of immunotherapy responses by integrating systematic aptamer ligand tailoring, ultrasensitive ellipsometry‐based sensing, and clinically relevant tumor‐proximal fluid sampling. Aptamers specifically targeting PD‐L1 are identified through systematic evolution of ligands by exponential enrichment (SELEX), followed by truncation and computational sequence refinement to enhance binding specificity. The optimized aptamer sequence (Tr‐Apt13) is validated from molecular interaction analyses to in vitro assays, demonstrating superior target binding efficacy over conventional antibodies, attributed to dense surface immobilization and multivalent binding capability. When incorporated into an ellipsometry‐based dual‐prism solution‐immersed silicon sensor, Tr‐Apt13 enabled ultrasensitive detection of PD‐L1–expressing exosomes with a detection limit of ≈9.8 particles mL ⁻¹ , exhibiting high linearity and stability. Clinical validation using bronchoalveolar lavage fluid (BALF) from lung cancer patients revealed precise discrimination between responders and non‐responders at exosome concentrations as low as 10 ³ particles mL ⁻¹ , outperforming serum‐based analysis, conventional ELISA, and tissue immunohistochemistry. Collectively, this multi‐level strategy offers a new perspective on exosome‐based diagnostics, enabling precise prediction of immunotherapy efficacy in lung cancer patients.