Sensors & diagnostics最新文献

Wearable physical sensors represent attractive devices for health monitoring and human–machine interfaces. Unlike traditional devices that prioritize increased sensitivity and selectivity, stretchability is crucial for wearable sensors to effectively adhere to the dynamic and curved contours of the human body. In addition to being stretchable, the conformal integration allows for durable skin–device interfaces, enabling long-term wearable detection. To track the latest progress, this perspective focuses on the rapidly advancing field of skin-attached physical sensors, analyzing their design approaches, critical applications, and desirable characteristics. The discussion begins with two primary strategies for creating stretchable electronic devices through structural designs and material innovations. We further discuss the significance of a conformal, seamless skin–device interface for wearable detection. We further elaborate on several critical physical sensors and their system integration. Finally, this article addresses current challenges and outlines future directions to translate knowledge in this evolving field into cutting-edge wearable technologies.

Tumor cells have high metabolic demands, leading to increased oxygen consumption and further exacerbating hypoxia, which has been regarded as a characteristic feature of solid tumors and plays a significant role in tumor growth, resistance to therapy, and overall treatment outcomes. Hypoxia-specific sensing probes are currently in urgent need to provide valuable information for tumor detection and monitoring. In this work, we developed a new near-IR fluorescence-emitting biosensor with a high fluorescence quantum yield for hypoxia detection in tumor tissues. In the presence of nitroreductase enzyme under tumor hypoxia, the nitro group of the biosensor molecule is converted into an amino group, and the resulting compound turns itself into a nonfluorescent dye through a self-immolating process, thus turning off the fluorescence emission of the biosensor. The fluorescence change of the biosensor in response to nitroreductase is sensitive and selective and is not influenced by the presence of other physiologically important species. In the in vitro and in vivo bioimaging experiments, the biosensor demonstrated high efficiency in detecting hypoxia and the capability of distinguishing solid tumors of different sizes, indicating its potential applications in tumor diagnosis and progression monitoring.

We report the facile detection of a pancreatic cancer biomarker α-chymotrypsin (Chy) by turn-on, time-gated lanthanide luminescence for the first time. To the best of our knowledge, the non-peptide probe we designed is the simplest one currently available. The probe undergoes Chy-induced release of the sensitizing antenna (2,3-dihydroxynaphthalene), leading to enhanced lanthanide luminescence. The detection protocol was further modified to develop a paper-based sensor and was used to detect Chy in commercial tablets, and to rapidly screen Chy-inhibitors.

Genetically-encoded, fluorescent protein (FP)-based biosensors are powerful tools for imaging dynamic cellular activities. Directed evolution is a highly effective method for developing enhanced versions of FP-based biosensors, but the screening process is laborious and time-consuming. Mammalian cell-based screening with electrical stimulation methods has been successful in accurately selecting variants of biosensors for imaging neuronal activities. We introduce an automated mammalian cell screening platform utilizing a fluorescence microscope and a liquid dispenser to enable the screening of biosensor responsiveness to chemical stimulation. We demonstrated the effectiveness of this platform in improving the response of a red fluorescent biosensor for Ca²⁺, K-GECO, for detection of histamine-induced changes in Ca²⁺ concentration. This method should be applicable to any FP-based biosensor that responds to pharmacological treatment or other exogenous chemical stimulation, simplifying efforts to develop biosensors tailored for specific applications in diverse biological contexts.

Accurately identifying tumor tissue is crucial during surgery, especially when removing head and neck squamous cell carcinomas (HNSCC). Our tumor-responsive probes are tailored for ex vivo diagnostics, streamlining today's complex surgical workflows and potentially enabling pathologists and surgeons to rapidly and objectively distinguish between healthy and tumor tissue. Designed based on insights from biological furin substrates and cleavage site screening, the probes detect HNSCC-associated protease activity. Within ten minutes of incubation, tumor tissue is differentiated from healthy tissue by visible fluorescence in biopsy supernatant.

Glycated hemoglobin (HbA1c) is a pivotal biomarker for the monitoring and early diagnosis of diabetes. The CRISPR-Cas system has fascinating application prospects in the next generation of biosensors due to its high specificity, efficiency, flexibility, and customization. Herein, a label-free electrochemical aptasensor was designed for the detection of HbA1c by combining the specific recognition ability of aptamers with the signal amplification effect of the CRISPR-Cas12a system. In the presence of HbA1c, the cis–trans cleavage ability of Cas12a protein was activated, causing the pre-formed probe DNA to be heavily cleaved and the electrochemical signal to increase. With CRISPR-assisted signal amplification, the developed electrochemical aptasensor can detect as low as 0.84 ng mL⁻¹ HbA1c. Moreover, this aptasensor can detect 10 ng mL⁻¹ HbA1c in 50% human serum due to its high selectivity, reproducibility, and long-term stability, which is lower than its physiological level in human blood samples. All results proved that the proposed aptasensor has a promising application in the early diagnosis and long-term monitoring of diabetes.

A novel alternative to cope with saliva-to-saliva variations and cross-interference while sensing delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) is reported here using two voltammetric sensors coupled with machine learning. The screen-printed electrodes modified with the same analyte molecules (m-Z-THC and m-Z-CBD) were employed for sensing ultra-low concentrations of THC and CBD in the 0 to 5 ng mL⁻¹ range in real human saliva samples. Simultaneous detection of THC and CBD was carried out using m-Z-THC or m-Z-CBD to study the performance of each modified sensor. Also, CBD and THC have the same molecular structure; there is only a slight difference in how the atoms are arranged, and therefore both molecules will have similar electrochemical performance. Consequently, CBD can be a potential interference while detecting THC and THC can be an interference during CBD detection using electrochemical sensors. Therefore, machine learning was introduced to analyze the sensor analytical responses to overcome such issues. The data processing results provide suitable accuracies of 100% for training in the case of both sensors and 92 and 83% for m-Z-THC and m-Z-CBD, respectively, for dataset testing THC and CBD in saliva samples. Additionally, the saliva samples containing CBD and THC as cross-interference were accurately identified and classified.

MicroRNAs (miRNAs) are short (about 18–24 nucleotides) non-coding RNAs and have emerged as potential biomarkers for various diseases, including cancers. Due to their short lengths, the specificity often becomes an issue in conventional amplification-based methods. Next-generation sequencing techniques could be an alternative, but the long analysis time and expensive costs make them less suitable for routine clinical diagnosis. Therefore, it is essential to develop a rapid, selective, and accurate miRNA detection assay using a simple, affordable system. In this work, we report a CRISPR/Cas13a-based miRNA biosensing using point-of-care dark-field (DF) imaging. We utilized magnetic-gold nanoparticle (MGNPs) complexes as signal probes, which consist of 200 nm-sized magnetic beads and 60 nm-sized gold nanoparticles (AuNPs) linked by DNA hybridization. Once the CRISPR/Cas13a system recognized the target miRNAs (miR-21-5p), the activated Cas13a cleaved the bridge linker containing RNA sequences, releasing 60 nm-AuNPs detected and quantified by a portable DF imaging system. The combination of CRISPR/Cas13a, MGNPs, and DF imaging demonstrated amplification-free detection of miR-21-5p within 30 min at a detection limit of 500 attomoles (25 pM) and with single-base specificity. The CRISPR/Cas13a-assisted MGNP-DF assay achieved rapid, selective, and accurate detection of miRNAs with simple equipment, thus providing a potential application for cancer diagnosis.

Point-of-care (POC) biosensors have enormous potential to help guide and inform clinical decisions at a patient's location. They are particularly relevant to underserved populations, and people living in remote locations where healthcare infrastructure and resources are often limited. The translation of effective POC biosensors into commercial products is rapidly growing across many research fields. A significant quantity of scientific articles focused on the fundamental, applied, and proof-of-concept aspects of biosensing are reported each year. However, this extensive body of work is not reflected in the comparatively small number of commercial biosensors available on the market. Here, we discuss key aspects of the biosensor translation process including the selection of analytical biomarkers in various body fluids, clinical trials, regulatory approval, consumer engagement, manufacturing and scale-up strategies, health economics, and legal and ethical considerations.

This present work aimed to craft copper (Cu²⁺)-doped carbon dots (CuCDs) for the selective and sensitive detection of a guanine nucleobase. By employing a hydrothermal method, we synthesized blue-emitting CuCDs having emission maxima at 423 nm. CuCDs were used as a fluorescence turn-on ratiometric probe to detect guanine, a critical purine base in DNA involved in energy transduction, cell signalling, and metabolic processes. In the presence of guanine, the fluorescence intensity of CuCDs significantly increased due to the stable non-covalent interaction between Cu²⁺ and guanine. CuCDs achieved a very low limit of detection (LOD) of 0.59 nM for guanine as a highly sensitive probe. CuCDs demonstrated selectivity for guanine with no interference from other nucleobases (adenine, thymine, and cytosine) and various biomolecules and metal ions commonly found in the cellular environment. In addition, CuCDs demonstrated a higher affinity for guanine-enriched oligonucleotide cMYC G 27-mer over dsDNA 26-mer devoid of a large guanine population. Furthermore, the fluorescence intensity of CuCDs increased in guanine-treated mammalian cells and G-quadruplex-enriched cancer cells compared with that in non-cancerous cells. Hence, we developed a highly sensitive ratiometric fluorescence probe, CuCDs, for the selective detection of guanine both in vitro and within mammalian cells via a “fluorescence turn-on mechanism”.