ACS Sensors

Cluster-Enhanced Nanopore Sensing of Ovarian Cancer Marker Peptides in Urine

The development of novel methodologies that can detect biomarkers from cancer or other diseases is both a challenge and a need for clinical applications. This partly motivates efforts related to nanopore-based peptide sensing. Recent work has focused on the use of gold nanoparticles for selective detection of cysteine-containing peptides. Specifically, tiopronin-capped gold nanoparticles, trapped in the cis-side of a wild-type α-hemolysin nanopore, provide a suitable anchor for the attachment of cysteine-containing peptides. It was recently shown that the attachment of these peptides onto a nanoparticle yields unique current signatures that can be used to identify the peptide. In this article, we apply this technique to the detection of ovarian cancer marker peptides ranging in length from 8 to 23 amino acid residues. It is found that sequence variability complicates the detection of low-molecular-weight peptides (<10 amino acid residues), but higher-molecular-weight peptides yield complex, high-frequency current fluctuations. These fluctuations are characterized with chi-squared and autocorrelation analyses that yield significantly improved selectivity when compared to traditional open-pore analysis. We demonstrate that the technique is capable of detecting the only two cysteine-containing peptides from LRG-1, an emerging protein biomarker, that are uniquely present in the urine of ovarian cancer patients. We further demonstrate the detection of one of these LRG-1 peptides spiked into a sample of human female urine.

SERS-Nanozyme Cooperative Ag@Lacunary-POM Nanoclusters for Exosome Biosensing

The detection of cancer-related exosomes is of great significance for the early diagnosis of cancer and the prediction of prognosis. We developed a SERS-based nanozyme-linked immunosorbent assay (NELISA) utilizing lacunary polyoxometalate Na

Dual Gatekeepers-Driven Signal Amplification Strategy for Precise Detection and Modulation of Ovarian Cancer Exosome Subtypes

Early detection of ovarian cancer remains a significant challenge due to the lack of symptoms in its early stages and the overlap in protein expression patterns between malignant and benign conditions. In this study, we introduce a dual gatekeepers-driven signal amplification strategy for the highly sensitive detection and precise modulation of ovarian cancer-derived exosome subtypes. By employing CA125 and carcinoembryonic antigen (CEA) aptamers as dual gatekeepers, this strategy selectively activates functional regions on exosome membranes, triggering the opening of hairpin DNA structures (HP) upon recognition of specific protein patterns. The opened HP then initiate an exonuclease III-powered DNA walking system and nucleic acid-stabilized Ag

Plasmonic Fiber Optic Sensing Platform for Point-of-Care Pharmacokinetic Monitoring of Platinum Chemotherapeutics: Toward Ultratrace Multi-omics Precision Chemotherapy Management

Precision chemotherapy management requires efficient and ultrasensitive dynamic monitoring of drug pharmacokinetics alongside real-time tracking of critical biomarker responses, yet existing clinical diagnostic systems neither achieve real-time integration of these critical parameters nor provide point-of-care testing (POCT) capabilities within a unified analytical framework. Here, we develop a plasmonic fiber-optic sensing platform based on tilted fiber Bragg grating surface plasmon resonance (TFBG-SPR) for point-of-care pharmacokinetic monitoring of platinum chemotherapeutics. By utilizing programmable DNA-based biosensors, our system achieves femtomolar-level detection limits for platinum drugs in minimal sample volumes (10 μL, 100-fold dilution). The platform's modular design enables rapid adaptation to diverse molecular targets with ultratrace multichannel spectral detection, providing inherent capability for parallelized multiomics monitoring by simultaneously addressing chemotherapeutics, DNA, RNA, and protein targets. In a longitudinal clinical cohort study via our proposed sensing platform, we observed an inverse correlation between platinum drug concentrations and miRNA-21 expression levels in colorectal cancer patients undergoing dose-adjusted chemotherapy, while ovarian cancer patients exhibited dynamic miRNA-21 responses to platinum drug concentration variations. These findings highlight the potential utility of miRNA-21 as a candidate biomarker for further investigation into drug efficacy and tumor progression mechanisms. By integrating ultratrace drug monitoring with targeted multiomics profiling on a unified platform─a critical prerequisite for data standardization in future artificial intelligence-driven analysis, our platform bridges the gap between clinical pharmacokinetics and molecular biomarker analysis, offering a fundamental POCT tool for precision chemotherapy optimization and personalized cancer management.

Dual-Aptamer Recognition of DNA Logic Gate Sensor-Based Specific Exosomal Proteins for Ovarian Cancer Diagnosis

Clinical diagnosis of ovarian cancer lacks high accuracy due to the weak selection of specific biomarkers along with the circumstance biomarkers localization. Clustering analysis of proteins transported on exosomes enables a more precise screening of effective biomarkers. Herein, through bioinformatics analysis of ovarian cancer and exosome proteomes, two coexpressed proteins, EpCAM and CD24, specifically enriched, were identified, together with the development of an as-derived dual-aptamer targeted exosome-based strategy for ovarian cancer screening. In brief, a DNA ternary polymer with aptamers targeting EpCAM and CD24 was designed to present a logic gate reaction upon recognizing ovarian cancer exosomes, triggering a rolling circle amplification chemiluminescent signal. A dynamic detection range of 6 orders of magnitude was achieved by quantifying exosomes. Moreover, for clinical samples, this strategy could accurately differentiate exosomes from healthy persons, other cancer patients, and ovarian cancer patients, enabling promising

Electrochemical Sensor for the Detection and Accurate Early Diagnosis of Ovarian Cancer

Ovarian cancer (OC) has the highest mortality rate among malignant tumors, primarily because it is difficult to diagnose early. Exosomes, a type of extracellular vesicle rich in parental information, have garnered significant attention in the field of cancer diagnosis and treatment. They play an important regulatory role in the occurrence, development, and metastasis of OC. Consequently, exosomes have emerged as noninvasive biomarkers for early cancer detection. Therefore, identifying cancer-derived exosomes may offer a novel biomarker for the early detection of OC. In this study, we developed a metal-organic frameworks assembled "double hook"-type aptamer electrochemical sensor, which enables accurate early diagnosis of OC. Under optimal experimental conditions, electrochemical impedance spectroscopy technology demonstrated a good linear relationship within the concentration range of 31-3.1 × 10

Tandem SERS and MS/MS Profiling of Plasma Extracellular Vesicles for Early Ovarian Cancer Biomarker Discovery

CRISPR/Cas on Microfluidic Paper-Based Analytical Devices for Point-of-Care Screening of Cervical Cancer

Highly sensitive point-of-care early screening for high-risk human papillomavirus (HPV) infections is urgently needed, particularly in resource-limited settings. Nucleic acid amplification methods, especially CRISPR/Cas-based biosensors, have emerged as promising tools for sensitive HPV detection; however, current approaches typically rely on tedious tube-based formats coupled with lateral flow assays for signal readout in point-of-care testing (POCT). Here, we developed customized microfluidic paper-based analytical devices (μPADs) with valves that seamlessly integrated recombinase polymerase amplification (RPA) with CRISPR/Cas12a biosensing (RPA-CRISPR/Cas12a) on the filter paper substrate. This innovation achieved sensitive and cost-effective high-risk HPV detection in POCT. The RPA-CRISPR/Cas12a system with a linear reporter on μPADs, enabled fluorescence detection of the E7 gene, achieving a sensitivity of 1 pM at approximately 1 h. The sensitivity was further enhanced by introducing a circular reporter into the fluorescence-based RPA-CRISPR/Cas12a system on μPADs, enabling detection of the E7 gene with a detection limit of 1 fM and an assay time of 35 min. The system was validated using 50 cervical swab clinical samples, demonstrating 95% sensitivity and 100% specificity when compared to qPCR. This sample-to-answer detection platform holds significant promise for early screening of high-risk HPV infections in point-of-care scenarios.

Purification of Circulating Tumor Cells Based on Multiantibody-Modified Magnetic Nanoparticles and Molecular Analysis toward Epithelial Ovarian Cancer Detection

Circulating tumor cells (CTCs) are valuable circulating biomarkers of cancer, which carry primary tumor information and may provide real-time assessment of tumor status as well as treatment response in cancer patients. Herein, we developed a novel assay for accurate diagnosis and dynamic monitoring of epithelial ovarian cancer (EOC) using CTC RNA analysis. Multiantibody-modified magnetic nanoparticles were prepared for purification of EOC CTCs from whole blood samples of clinical patients. Subsequently, nine EOC-specific mRNAs of purified CTCs were quantified using droplet digital PCR. The EOC CTC Score was generated using a multivariate logistic regression model for each sample based on the transcripts of the nine genes. This assay exhibited a distinguishing diagnostic performance for the detection of EOC (

Electrochemical Immunosensor for Ultra-Low Detection of Human Papillomavirus Biomarker for Cervical Cancer

Human papillomavirus (HPV) is the causative agent for cervical cancer. Of the various types of HPV, the high-risk HPV-16 type is the most important antigenic high-risk HPV. In this work, the antigenic HPV-16 L1 peptide was immobilized on a glassy carbon electrode and used to detect several concentrations of the anti-HPV-16 L1 antibody, and vice versa. Two electrode platforms were used: onion-like carbon (OLC) and its polyacrylonitrile (OLC-PAN) composites. Both platforms gave a wide linear concentration range (1.95 fg/mL to 6.25 ng/mL), excellent sensitivity (>5.2 μA/log ([HPV-16 L1, fg/mL]), and extra-ordinarily low limit of detection (LoD) of 1.83 fg/mL (32.7 aM) and 0.61 fg/mL (10.9 aM) for OLC-PAN and OLC-based immunosensors, respectively. OLC-PAN modified with the HPV-16 L1 protein showed low LoD for the HPV-16 L1 antibody (2.54 fg/mL, i.e., 45.36 aM), proving its potential use for screening purposes. The specificity of detection was proven with the anti-ovalbumin antibody (anti-OVA) and native ovalbumin protein (OVA). An immobilized antigenic HPV-16 L1 peptide showed insignificant interaction with anti-OVA in contrast with the excellent interaction with anti-HPV-16 L1 antibody, thus proving high specificity. The application of the immunosensor as a potential point-of-care (PoC) diagnostic device was investigated with screen-printed carbon electrodes, which detected ultra-low (ca. 0.7 fg/mL ≈ 12.5 aM) and high (ca. 12 μg/mL ≈ 0.21 μM) concentrations. This study represents the lowest LoD reported for HPV-16 L1. It opens the door for further investigation with other electrode platforms and realization of PoC diagnostic devices for screening and testing of HPV biomarkers for cervical cancer.

Plasmonic Nanoparticle-Based Digital Cytometry to Quantify MUC16 Binding on the Surface of Leukocytes in Ovarian Cancer

Although levels of the circulating ovarian cancer marker (CA125) can distinguish ovarian masses that are likely to be malignant and correlate with severity of disease, serum CA125 has not proved useful in general population screening. Recently, cell culture studies have indicated that MUC16 may bind to the Siglec-9 receptor on natural killer (NK) cells where it downregulates the cytotoxicity of NK cells, allowing ovarian cancer cells to evade immune surveillance. We present evidence that the presence of MUC16 can be locally visualized and imaged on the surface of peripheral blood mononuclear cells (PBMCs) in ovarian cancer via a novel "digital" cytometry technique that incorporates: (i) OC125 monoclonal antibody-conjugated gold nanoparticles as optical nanoprobes, (ii) a high contrast dark-field microscopy system to detect PBMC-bound gold nanoparticles, and (iii) a computational algorithm for automatic counting of these nanoparticles to estimate the quantity of surface-bound MUC16. The quantitative detection of our technique was successfully demonstrated by discriminating clones of the ovarian cancer cell line, OVCAR3, based on low, intermediate, and high expression levels of MUC16. Additionally, PBMC surface-bound MUC16 was tracked in an ovarian cancer patient over a 17 month period; the results suggest that the binding of MUC16 on the surface of immune cells may play an early indicator for recurrent metastasis 6 months before computational tomography-based clinical diagnosis. We also demonstrate that the levels of surface-bound MUC16 on PBMCs from five ovarian cancer patients were greater than those from five healthy controls.