An official website of the United States government
A device incorporating both Rayleigh wave and shear horizontal surface acoustic waves is made on a ST-Quartz substrate. The Rayleigh wave induced microfluidic mixing shows effects on accelerating the binding kinetics of real-time sensing between antibody and antigen, which is measured by phase change from the shear horizontal surface acoustic wave direction on the ST-Quartz. Preliminary results on this device show shortened response time and enhanced phase signal when the binding is accelerated by microfluidic streaming from the Rayleigh wave. The device can be fabricated using a low cost, single step photolithography method and can be combined with a small electronic sensor for data readout, which allows for a variety of surface-based biomarker detections on a portable platform. In this work, detection of Carcinoembryonic antigen (CEA) binding with functionalized capture antibody is studied to show the effects of mass loading amplification due to Rayleigh wave microfluidic streaming.
more »
« less
Metal-enhanced immunofluorescence assays for detection of carcinoembryonic antigen
Carcinoembryonic antigen (CEA) is a glycosylphosphatidylinositol cell surface anchored glycoprotein that is a well-known, broad spectrum biomarker related to various cancers and it is also an indicator of disease recurrence. In this work, metal-enhanced fluorescence (MEF) is utilized to lower the detection limit of CEA in immunofluorescence assays. Silver nanocubes (AgNCs) of 50 nm edge-length were incubated to plasmonically enhance fluorescence intensity. This increased sensor sensitivity by a factor of 6 and lowered the limit of detection to below 1 ng/mL in fluorescence detection of the antigen.
more »
« less
- Award ID(s):
- 1640668
- PAR ID:
- 10050295
- Date Published:
- Journal Name:
- SENSORS, 2017 IEEE
- Page Range / eLocation ID:
- 1 to 3
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Sensitive detection of pathogens is crucial for early disease diagnosis and quarantine, which is of tremendous need in controlling severe and fatal illness epidemics such as of Ebola virus (EBOV) disease. Serology assays can detect EBOV‐specific antigens and antibodies cost‐effectively without sophisticated equipment; however, they are less sensitive than reverse transcriptase polymerase chain reaction (RT‐PCR) tests. Herein, a 3D plasmonic nanoantenna assay sensor is developed as an on‐chip immunoassay platform for ultrasensitive detection of Ebola virus (EBOV) antigens. The EBOV sensor exhibits substantial fluorescence intensity enhancement in immunoassays compared to flat gold substrate. The nanoantenna‐based biosensor successfully detects EBOV soluble glycoprotein (sGP) in human plasma down to 220 fg mL−1, a significant 240 000‐fold sensitivity improvement compared to the 53 ng mL−1EBOV antigen detection limit of the existing rapid EBOV immunoassay. In a mock clinical trial, the sensor detects sGP‐spiked human plasma samples at two times the limit of detection with 95.8% sensitivity. The results combined highlight the nanosensor's extraordinary capability of detecting EBOV antigen at ultralow concentration compared to existing immunoassay methods. It is a promising next‐generation bioassay platform for early‐stage disease diagnosis and pathogen detection for both public health and national security applications.more » « less
-
To sensitively detect multiple and cross-species disease-related targets from a single biological sample in a quick and reliable manner is of high importance in accurately diagnosing and monitoring diseases. Herein, a surface-enhanced Raman scattering (SERS) sensor based on a functionalized multiple-armed tetrahedral DNA nanostructure (FMTDN) immobilized silver nanorod (AgNR) array substrate and Au nanoparticle (AuNP) SERS tags is constructed to achieve both multiplex detection and enhanced sensitivity using a sandwich strategy. The sensor can achieve single, dual, and triple biomarker detections of three lung cancer-related nucleic acid and protein biomarkers, i.e. , miRNA-21, miRNA-486 and carcinoembryonic antigen (CEA) in human serum. The enhanced SERS signals in multiplex detections are due to the DNA self-assembled AuNP clusters on the silver nanorod array during the assay, and the experimentally obtained relative enhancement factor ratios, 150 for AuNP dimers and 840 for AuNP trimers, qualitatively agree with the numerically calculated local electric field enhancements. The proposed FMTDN-functionalized AgNR SERS sensor is capable of multiplex and cross-species detection of nucleic acid and protein biomarkers with improved sensitivity, which has great potential for the screening and clinical diagnosis of cancer in the early stage.more » « less
-
Abstract Despite major advances in HIV testing, ultrasensitive detection of early infection remains challenging, especially for the viral capsid protein p24, which is an early virological biomarker of HIV-1 infection. Here, To improve p24 detection in patients missed by immunological tests that dominate the diagnostics market, we show a click chemistry amplified nanopore (CAN) assay for ultrasensitive quantitative detection. This strategy achieves a 20.8 fM (0.5 pg/ml) limit of detection for HIV-1 p24 antigen in human serum, demonstrating 20~100-fold higher analytical sensitivity than nanocluster-based immunoassays and clinically used enzyme-linked immunosorbent assay, respectively. Clinical validation of the CAN assay in a pilot cohort shows p24 quantification at ultra-low concentration range and correlation with CD4 count and viral load. We believe that this strategy can improve the utility of p24 antigen in detecting early infection and monitoring HIV progression and treatment efficacy, and also can be readily modified to detect other infectious diseases.more » « less
-
Rapid and ultrasensitive point-of-care RNA detection plays a critical role in the diagnosis and management of various infectious diseases. The gold-standard detection method of reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is ultrasensitive and accurate yet limited by the lengthy turnaround time (1-2 days). On the other hand, antigen test offers rapid at-home detection (15-20 min) but suffers from low sensitivity and high false-negative rates. An ideal point-of-care diagnostic device would combine the merits of PCR-level sensitivity and rapid sample-to-result workflow comparable to antigen testing. However, the existing RNA detection platform typically possesses superior sensitivity or rapid sample-to-result time, but not both. This paper reports a point-of-care microfluidic device that offers ultrasensitive yet rapid detection of viral RNA from clinical samples. The device consists of a microfluidic chip for precisely manipulating small volumes of samples, a miniaturized heater for viral lysis and ribonuclease (RNase) inactivation, a CRISPR Cas13a- electrochemical sensor for target preamplification-free and ultrasensitive RNA detection, and a smartphone-compatible potentiostat for data acquisition. As demonstrations, the devices achieve the detection of heat-inactivated SARS-CoV-2 samples with a limit of detection (LOD) down to 10 aM within 25 minutes, which is comparable to the sensitivity of RT-PCR and rapidness of antigen test. The platform also successfully distinguishes all nine positive unprocessed clinical SARS-CoV-2 nasopharyngeal swab samples from four negative samples within 25 minutes of sample-to-result time. Together, this device provides a point-of-care solution that can be deployed in diverse settings beyond laboratory environments for rapid and accurate detection of RNA from clinical samples. The device can potentially be expandable to detect other viral targets, such as human immunodeficiency virus (HIV) self-testing and Zika virus, where rapid and ultrasensitive point-of-care detection is required.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/ICSENS.2017.8234349
