Biosensors-Basel最新文献

The pervasive presence of foodborne contaminants in foods poses a significant global threat, contributing to various foodborne diseases and food safety issues. Therefore, developing rapid, sensitive, and universal detection methods for them is essential to ensure public health and food safety. Electrochemiluminescence (ECL) sensors, particularly those incorporating innovative nanoaggregates, have been widely used to detect related contaminant residues in foodstuffs owing to their superior sensitivity and low background signals. This review summarizes recent advances in nanoaggregate-based novel ECL sensors for detecting a wide range of contaminants, with emphasis on their fundamentals and representative applications. This area has not yet been comprehensively covered in the existing literature. The current challenges and emerging trends for next-generation ECL sensors based on nanoaggregates in food safety monitoring are also discussed.

Manual palpation serves as a conventional clinical method for assessing soft tissue stiffness; however, its results are susceptible to subjective factors and exhibit limited reliability. To achieve objective evaluation of pathological tissue stiffness, this study utilizes ultrasonic transducers to measure the time-of-flight (ToF) difference in ultrasound signals in silicone samples and ex vivo animal tissues under specific pressure gradients. A correlation model between the ToF difference and tissue stiffness was established, thereby enabling the detection of tissue stiffness. Based on this methodology, a wearable sensing system incorporating ultrasonic transducers was developed. The system applies fixed gradient pressure to human tissues via a pneumatic control unit and detects the corresponding ToF difference, allowing real-time monitoring of stiffness variations in the biceps brachii and thigh during relaxation and contraction, in the forearm during gripping and release actions, as well as in simulated lesions. This study provides a quantitative technological framework for wearable tissue stiffness monitoring, and its objective measurement characteristics offer support for clinical diagnostic decision-making.

Acute myocardial infarction (AMI) is a rapidly progressing cardiovascular condition associated with high mortality. Myoglobin is an early biomarker of AMI; however, its detection using conventional methods is limited by complex workflows and low resistance to interference. In this study, we developed an integrated myoglobin detection platform that combined magneto-immunoassay with microfluidic technology. A giant magnetoresistance (GMR) sensor was fabricated using micro-electro-mechanical systems (MEMS). The designed microfluidic chip integrated sample pretreatment, immunoreaction, and magnetic signal capture functionalities. Its built-in GMR sensor, labeled with magnetic nanoparticles, directly converted the "antigen-antibody" biochemical signal into detectable magnetoresistance changes, thereby enabling the indirect detection of myoglobin. A magneto-immunoassay analysis system consisted of a fluidic drive, magnetic field control, and data acquisition functions. Various key parameters were optimized, including EDC/NHS concentration, antibody concentration, and magnetic bead size. Under the optimal conditions and using 1 μm magnetic beads as labels and an external detection magnetic field of 60 Oe, the platform successfully detected myoglobin at 75 ng/mL with ∆MR ≥ 0.202%. Specificity tests demonstrated that the platform had high specificity for myoglobin and could effectively distinguish myoglobin from bovine serum albumin (BSA) and troponin I. This study presents a rapid, accurate myoglobin detection platform that can be applied for the early diagnosis of AMI.

Cancer stem cells (CSCs) remain challenging to isolate and characterize because of their plastic phenotype. To overcome this issue, we used a microfluidic lab-on-a-chip analysis approach based on ultra-high frequency dielectophoresis (UHF-DEP) to measure the dielectrophoretic signature of colorectal cancer cells. We demonstrated that CSCs exhibit a distinct and lower frequency signature than differentiated cancer cells. Extracellular vesicles (EVs) released by tumor cells are implicated in tumor progression and metastasis. As CSC-derived EVs carry a more aggressive cargo, we hypothesized that treating differentiated colorectal cancer cells with these vesicles might affect their phenotype which would be detected by our lab on a chip. Indeed, the dielectrophoretic signature of cells treated with those EVs was altered in comparison to untreated cells, even in cases where no detectable biological changes were observed. Compared to conventional approaches using biomarkers to characterize CSCs, this UHF-DEP lab on a chip is a label-free method providing rapid and relevant results. Such a method could be useful in the clinic for the early detection of CSCs in the tumor mass, as well as for monitoring CSC-derived EVs in the bloodstream in order to study responses to therapy and prevent relapses.

Heme, a protoporphyrin IX iron complex, functions as an essential prosthetic group in hemoglobin and myoglobin, mediating oxygen storage and transport. Additionally, heme serves as a critical cofactor in various enzymes such as cytochrome c, enabling electron transfer within the mitochondrial respiratory chain. Unlike protein-bound heme, free or labile heme exhibits cytotoxic, pro-oxidant, and pro-inflammatory properties. Elevated levels of free heme are associated with various pathophysiological conditions, including hemolytic disorders such as sickle cell disease, malaria, and sepsis. In this review, we introduce the physiological roles of heme and its involvement in human health and disease. We also examine the mechanisms of heme sensing and regulation in bacterial cells. A variety of analytical methods have been developed to detect and quantify heme, enabling differentiation between protein-bound and free forms. These tools are discussed in the context of their applications in studying cellular heme regulation and their use in monitoring pathological conditions in humans. In particular, we describe examples of biosensors employing bacterial heme sensor proteins as recognition elements.

A novel, label-free chemiluminescence sensing platform for CpG methylation was developed, leveraging the G-quadruplex (G4) structural sensitivity of G4-protein interactions to eliminate bisulfite conversion. This sensing system is based on the enhancement of luminol chemiluminescence generated from myoglobin upon binding to the G4-forming DNA. At the core of this biosensor is the G4-structure-dependent modulation of the peroxidase-like activity generating luminol chemiluminescence of myoglobin. The structural change by CpG methylation within the G4-forming sequence of the B cell lymphoma 2 (BCL2) gene promoter altered its binding to myoglobin, transducing the methylation state into a measurable signal catalyzed by myoglobin. This principle was validated in a practical assay using immobilized probes to capture the target DNA for methylation analysis. This system demonstrated the capability to distinguish methylation differences of 50% when the target DNA concentration was over 25 nM. Versatility was further confirmed using the sequence from the dopamine receptor D2 (DRD2) gene promoter, where the methylation similarly induced distinct topological and functional changes. This is the first study to directly link the epigenetic state of a G4-forming DNA sequence to a protein-mediated enzymatic output, offering a framework for simple, rapid, and highly adaptable biosensors for research and clinical applications.

Digital microfluidic biochips (DMFBs) find extensive applications in biochemical experiments, medical diagnostics, and safety-critical domains, with their reliability dependent on efficient online testing technologies. However, traditional random search algorithms suffer from slow convergence and susceptibility to local optima under complex fluidic constraints. This paper proposes a hybrid optimization method based on priority strategy and an improved sparrow search algorithm for DMFB online test path planning. At the algorithmic level, the improved sparrow search algorithm incorporates three main components: tent chaotic mapping for population initialization, cosine adaptive weights together with Elite Opposition-based Learning (EOBL) to balance global exploration and local exploitation, and a Gaussian perturbation mechanism for fine-grained refinement of promising solutions. Concurrently, this paper proposes an intelligent rescue strategy that integrates global graph-theoretic pathfinding, local greedy heuristics, and space-time constraint verification to establish a closed-loop decision-making system. The experimental results show that the proposed algorithm is efficient. On the standard 7 × 7-15 × 15 DMFB benchmark chips, the shortest offline test path length obtained by the algorithm is equal to the length of the Euler path, indicating that, for these regular layouts, the shortest test path has reached the known optimal value. In both offline and online testing, the shortest paths found by the proposed method are better than or equal to those of existing mainstream algorithms. In particular, for the 15 × 15 chip under online testing, the proposed method reduces the path length from 543 and 471 to 446 compared with the IPSO and IACA algorithms, respectively, and reduces the standard deviation by 53.14% and 39.4% compared with IGWO in offline and online testing.

Over the past decade, the field of immunoassays and biosensing has undergone remarkable expansion, driven by the urgent demand for sensitive, rapid, and reliable detection technologies across biomedical, environmental, and food safety applications [...].

DNA nanoparticles have emerged as potent platforms for wearable and implantable biosensors owing to their molecular programmability, biocompatibility, and structural precision. This study delineates two principal categories of DNA-based sensing materials, DNA hydrogels and DNA origami, and encapsulates their fabrication methodologies, sensing mechanisms, and applications at the device level. DNA hydrogels serve as pliable, aqueous signal transduction mediums exhibiting stimulus-responsive characteristics, facilitating applications such as sweat-based cytokine detection with limits of detection as low as pg·mL^-1 and microneedle-integrated hydrogels for femtomolar miRNA sensing. DNA origami offers nanometer-scale spatial precision that improves electrochemical, optical, and plasmonic biosensing, as shown by origami-facilitated luminous nucleic acid detection and ultrasensitive circulating tumor DNA assays with fM-level sensitivity. Emerging integration technologies, such as flexible electronics, microfluidics, and wireless readout, are examined, alongside prospective developments in AI-assisted DNA design and materials produced from synthetic biology. This study offers a thorough and practical viewpoint on the progression of DNA nanotechnology for next-generation wearable and implantable biosensing devices.

Mycoplasma hominis (MH) is a prevalent opportunistic pathogen that is strongly associated with a wide range of urogenital tract infections and severe adverse pregnancy outcomes in clinical settings. Current MH detection methods, including microbial culture and qPCR, are time-consuming and rely on complex equipment, making them unsuitable for scenarios requiring rapid or simplified testing. In this study, we developed a visual readout biosensing platform by synergistically integrating recombinase polymerase amplification (RPA), CRISPR/Cas12a-mediated target nucleic acid recognition, and lateral flow biosensors for the rapid, sensitive, and specific identification of MH. The assay specifically targets the MH-specific 16S rRNA gene, achieving a limit of detection as low as 2 copies/reaction of recombinant plasmid containing the target gene with a total assay time of 60 min. Critical reaction parameters, including Cas12a-crRNA molar ratio, volume of RPA amplicon input, and Cas12a cleavage time, were systematically optimized to maximize the biosensor's response efficiency and detection reliability. The platform exhibited exceptional specificity, with no cross-reactivity observed against common co-occurring urogenital pathogens, and effectively minimized aerosol contamination risks via a rigorous decontamination workflow. Furthermore, this work represents the first documented implementation of a contamination-control protocol for an MH-specific CRISPR-LFA assay. Notably, testing results from 18 clinical samples demonstrated the high specificity of this assay, highlighting its promising potential for clinical application.