Detection of Epidermal Growth Factor Receptor Expression in Breast Cancer Cell Lines Using an Ion-Sensitive Field-Effect Transistor in Combination with Enzymatic Chemical Signal Amplification

Triple quenching effect of nanozyme catalyzed precipitation combined with enzyme-free amplification for photoelectrochemical biosensing of circulating tumor DNA

In this work, a new photoelectrochemical (PEC) biosensor based on triple quenching effect of nanozyme catalyzed precipitation to PEC signal of MgIn2S4 was constructed for ultrasensitive detection of circulating tumor DNA (ctDNA). Enzyme-free amplification technology was used to convert target ctDNA into a large number of product chains (PC) to improve the detection sensitivity. Co3O4 nanozyme with excellent peroxidase (POD)-like activity was introduced to the surface of MgIn2S4 by PC. Co3O4 could oxidize chromogenic agent 3-Amino-9-ethylcarbazole (AEC) to produce red insoluble precipitation in the presence of H2O2, resulting in the PEC signal "off" of MgIn2S4 to achieve ultrasensitive detection of ctDNA. In particular, Co3O4 nanozyme showed three synergistic quenching effects on PEC signal of MgIn2S4, which contributed greatly to improving the detection sensitivity. Firstly, the light absorption range of Co3O4 could reach 1000 nm, and compete with MgIn2S4 for light absorption. Secondly, the produced red precipitation belonged to the insulating material and had large electrochemical impedance, which hindered the transmission of photogenerated carriers. Thirdly, the precipitation also prevented the electron donor ascorbic acid (AA) from transferring electrons to MgIn2S4. This biosensor provided a promising sensitive PEC detection technology for ctDNA, and further broadened the application of nanozymes in the field of PEC analysis.

Impact of Nanomedicine in Women's Metastatic Breast Cancer

Metastatic breast cancer is responsible for 90% of mortalities among women suffering from various types of breast cancers. Traditional cancer treatments such as chemotherapy and radiation therapy can cause significant side effects and may not be effective in many cases. However, recent advances in nanomedicine have shown great promise in the treatment of metastatic breast cancer. For example, nanomedicine demonstrated robust capacity in detection of metastatic cancers at early stages (i.e., before the metastatic cells leave the initial tumor site), which gives clinicians a timely option to change their treatment process (for example, instead of endocrine therapy they may use chemotherapy). Here recent advances in nanomedicine technology in the identification and treatment of metastatic breast cancers are reviewed.

Ion-sensitive field effect transistor biosensors for biomarker detection: current progress and challenges

The ion-sensitive field effect transistor (ISFET) has emerged as a crucial sensor device, owing to its numerous benefits such as label-free operation, miniaturization, high sensitivity, and rapid response time. Currently, ISFET technology excels in detecting ions, nucleic acids, proteins, and cellular components, with widespread applications in early disease screening, condition monitoring, and drug analysis. Recent advancements in sensing techniques, coupled with breakthroughs in nanomaterials and microelectronics, have significantly improved sensor performance. These developments are steering ISFETs toward a promising future characterized by enhanced sensitivity, seamless integration, and multifaceted detection capabilities. This review explores the structure and operational principles of ISFETs, highlighting recent research in ISFET biosensors for biomarker detection. It also examines the limitations of these sensors, proposes potential solutions, and anticipates their future trajectory. This review aims to provide a valuable reference for advancing ISFETs in the field of biomarker measurement.

Zero-Background Dual-Mode Closed Bipolar Electrode Electrochemiluminescence Biosensor Based on ZnCoN-C Potential Regulation for Ultrasensitive Detection of Ochratoxin A

In this work, the relationship between electrochemiluminescence (ECL) signal and driving voltage was first studied by self-made reduced and oxidized closed bipolar electrodes (CBPEs). It was found that when the driving voltage was large enough, the maximum ECL signals for the two kinds of CBPEs were the same but their required drive voltages were different. Zinc cobalt nitrogen doped carbon material (ZnCoN-C) had an outstanding electric double layer (EDL) property and conductivity. Therefore, it could significantly reduce the driving voltage of two kinds of CBPE systems, reaching the maximum ECL signal of Ru(bpy)32+. Interestingly, when the ZnCoN-C modified electrode reached the maximum ECL signal, the bare electrode signal was zero. As a proof-of-concept application, a zero-background dual-mode CBPE-ECL biosensor was constructed for the ultrasensitive detection of ochratoxin A (OTA) in beer. Considering that beer samples contained a large number of reducing substances, a reduced CBPE system was selected to build the biosensor. Furthermore, a convenient ECL imaging platform using a smartphone was built for the detection of OTA. This work used a unique EDL material ZnCoN-C to regulate the driving voltage of CBPE for the first time; thus, a novel zero-background ECL sensor was constructed. Further, this work provided a deeper understanding of the CBPE-ECL system and opened a new door for zero-background detection.

Control of interface functions in solid-state biosensors for stable detection of molecular recognition

Significant progress has been achieved in the field of solid-state biosensors over the past 50 years. Various sensing devices with high-density integration and flexible configuration, as well as new applications for clinical diagnosis and healthcare, have been developed using blood, serum, and other body fluids such as sweat, tears, and saliva. A high-density array of ion-sensitive field effect transistors was developed by exploiting the advantages of advanced semiconductor technologies and commercialized in combination with an enzymatic primer extension reaction as a DNA sequencer in 2011. Different types of materials such as inorganic materials, metals, polymers, and biomolecules are mixed together on the surface of the gate while maintaining their own functions; therefore, compatibility among different materials has to be optimized so that the best detection performance of solid-state biosensors, including stability and reliability, is achieved as designed. Solid-state biosensors are suitable for the rapid, cost-effective, and noninvasive identification of biomarkers at various timepoints over the course of a disease.

Interface-Engineered Field-Effect Transistor Electronic Devices for Biosensing

Promising advances in molecular medicine have promoted the urgent requirement for reliable and sensitive diagnostic tools. Electronic biosensing devices based on field-effect transistors (FETs) exhibit a wide range of benefits, including rapid and label-free detection, high sensitivity, easy operation, and capability of integration, possessing significant potential for application in disease screening and health monitoring. In this perspective, the tremendous efforts and achievements in the development of high-performance FET biosensors in the past decade are summarized, with emphasis on the interface engineering of FET-based electrical platforms for biomolecule identification. First, an overview of engineering strategies for interface modulation and recognition element design is discussed in detail. For a further step, the applications of FET-based electrical devices for in vitro detection and real-time monitoring in biological systems are comprehensively reviewed. Finally, the key opportunities and challenges of FET-based electronic devices in biosensing are discussed. It is anticipated that a comprehensive understanding of interface engineering strategies in FET biosensors will inspire additional techniques for developing highly sensitive, specific, and stable FET biosensors as well as emerging designs for next-generation biosensing electronics.

Methods gold standard in clinic millifluidics multiplexed extended gate field-effect transistor biosensor with gold nanoantennae as signal amplifiers

We present a portable multiplexed biosensor platform based on the extended gate field-effect transistor and demonstrate its amplified response thanks to gold nanoparticle-based bioconjugates introduced as a part of the immunoassay. The platform comprises a disposable chip hosting an array of 32 extended gate electrodes, a readout module based on a single transistor operating in constant charge mode, and a multiplexer to scan sensing electrodes one-by-one. Although employing only off-the-shelf electronic components, our platform achieves sensitivities comparable to fully customized nanofabricated potentiometric sensors. In particular, it reaches a detection limit of 0.2 fM for the pure molecular assay when sensing horseradish peroxidase-linked secondary antibody (∼0.4 nM reached by standard microplate methods). Furthermore, with the gold nanoparticle bioconjugation format, we demonstrate ca. 5-fold amplification of the potentiometric response compared to a pure molecular assay, at the detection limit of 13.3 fM. Finally, we elaborate on the mechanism of this amplification and propose that nanoparticle-mediated disruption of the diffusion barrier layer is the main contributor to the potentiometric signal enhancement. These results show the great potential of our portable, sensitive, and cost-efficient biosensor for multidimensional diagnostics in the clinical and laboratory settings, including e.g., serological tests or pathogen screening.

Dual-probe ligation without PCR for fluorescent sandwich assay of EGFR nucleotide variants in magnetic gene capture platform

A simple, rapid, and highly efficient fluorescent detection technique without PCR through dual-probe ligation with the genetic capture of magnetic beads and reported probe was developed for determination of epidermal growth factor receptor (EGFR) gene exon 19 deletions. The EGFR exon 19 deletion mutation makes up 48% of all mutations associated with anti-tyrosine kinase inhibition sensitivity, and thus, the EGFR nucleotide variant is very important in clinical diagnosis. In this approach, the dual-probe ligation was designed to target exon 19 deletion. The magnetic genetic captured system was then applied to capture the successful dual-probe ligation. Thereafter, a reporter probe which is coupled with 6-fluorescein amidite (6-FAM) was introduced to hybridize with dual-probe ligation product on the surface of streptavidin magnetic beads, and finally, the supernatant was taken for fluorescence measurements for distinguishing mutant types from wild types. After optimization (the RSD of the fluorescent intensity was less than 4.5% (n = 3) under the optimal condition), 20 blind DNA samples from the population were analyzed by this technique and further confirmed by direct sequencing. The results of our assay matched to those from direct sequencing data, evidencing that the developed method is accurate and successful. These 20 blind DNA samples were diagnosed as wild and then spiked with different percentages of the mutant gene to quantify the ratio of the wild and mutant genes. This strategy was also successfully applied to quantify the ratio of the wild and mutant genes with good linearity at the λex/λem of 480 nm/520 nm (r = 0.996), and the limit of detection reached 1.0% mutant type. This simple fluorescent detection of nucleotide variants shows its potential to be considered a tool in biological and clinical diagnosis. Importantly, this strategy offers a universal detection capability for any kind of mutation (point, deletion, insertion, or substitution) in a gene of interest.