scholarly journals Abasic Site-Containing DNAzyme and Aptamer for Label-Free Fluorescent Detection of Pb2+and Adenosine with High Sensitivity, Selectivity, and Tunable Dynamic Range

2009 ◽  
Vol 131 (42) ◽  
pp. 15352-15357 ◽  
Author(s):  
Yu Xiang ◽  
Aijun Tong ◽  
Yi Lu
Keyword(s):  
Dynamic Range ◽  
High Sensitivity ◽  
Fluorescent Detection ◽  
Label Free ◽  
Abasic Site

Top-down Fabricated Polysilicon Nanoribbon Biosensor Chips for Cancer Diagnosis

2013 ◽  
Vol 1569 ◽  
pp. 213-218
Author(s):  
Hsiao-Kang Chang ◽  
Xiaoli Wang ◽  
Noppadol Aroonyadet ◽  
Rui Zhang ◽  
Yan Song ◽  
...  
Keyword(s):  
Dynamic Range ◽  
High Sensitivity ◽  
Cmos Process ◽  
Label Free ◽  
Top Down ◽  
Wide Dynamic Range ◽  
Critical Dimensions ◽  
Require Time ◽  
Significant Research ◽  
Conventional Photolithography

ABSTRACTNanobiosensors have drawn significant research interest in recent years owing to the advantages of label-free, electrical detection. However, nanobiosensors fabricated by bottom-up process are limited in terms of yield and device uniformity due to the challenges in assembly. Nanobiosensors fabricated by top-down process, on the other hand, exhibit better uniformity but require time and costly processes and materials to achieve the critical dimensions required for high sensitivity. In this report, we introduce a top-down nanobiosensor based on polysilicon nanoribbon. The polysilicon nanoribbon devices can be fabricated by conventional photolithography with only materials and equipments used in the standard CMOS process, thus resulting in great time and cost efficiency, as well as scalability. The devices show great response to pH changes with a wide dynamic range and high sensitivity. Biomarker detection is also demonstrated with clinically relevant sensitivity. Such results suggest that polysilicon nanoribbon devices exhibit great potential toward a highly efficient, reliable and sensitive biosensing platform.

scholarly journals Label-Free Assays on the BIND System

2004 ◽  
Vol 9 (6) ◽  
pp. 481-490 ◽  
Author(s):  
Brian T. Cunningham ◽  
Peter Li ◽  
Stephen Schulz ◽  
Bo Lin ◽  
Cheryl Baird ◽  
...  
Keyword(s):  
Fluorescent Dyes ◽  
Dynamic Range ◽  
Low Cost ◽  
High Sensitivity ◽  
Receptor Expression ◽  
Label Free ◽  
Protein Protein Interaction ◽  
Small Molecule Screening ◽  
Guided Mode ◽  
Wide Range

Screening of biochemical interactions becomes simpler, less expensive, and more accurate when labels, such as fluorescent dyes, radioactive markers, and colorimetric reactions, are not required to quantify detected material. SRU Biosystems has developed a biosensor technology that is manufactured on continuous sheets of plastic film and incorporated into standard microplates and microarray slides to enable label-free assays to be performed with high throughput, high sensitivity, and low cost per assay. The biosensor incorporates a narrow band guided-mode resonance reflectance filter, in which the reflected color is modulated by the attachment/detachment of biochemical material to the surface. The technology offers 4 orders of linear dynamic range and uniformity within a plate, with a coefficient of variation of 2.5%. Using conventional biochemical immobilization surface chemistries, a wide range of assay applications are enabled. Small molecule screening, cell proliferation/cytotoxicity, enzyme activity screening, protein-protein interaction, and cell membrane receptor expression are among the applications demonstrated.

scholarly journals Label-Free Fluorescent Aptasensor for Small Targets via Displacement of Groove Bound Curcumin Molecules

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4181 ◽  
Author(s):  
Baraa J. Alyamani ◽  
Omar A. Alsager ◽  
Mohammed Zourob
Keyword(s):  
Small Molecules ◽  
Dynamic Range ◽  
Fluorescent Sensor ◽  
Low Cost ◽  
High Sensitivity ◽  
Synthetic Dyes ◽  
Label Free ◽  
Target Molecule ◽  
Small Targets ◽  
Aptamer Sequence

Signal transduction based on fluorescence is one of the most common optical aptasensors for small molecules. Sensors with a number of unique features including high sensitivity, low cost, and simple operation can be constructed easily. However, the label-free fluorescent approach is limited to synthetic dyes that bind strongly to the aptamer sequence and result in a diminished sensor operation with high detection limits. In this study, we report the use of curcumin as a fluorescent probe to signal aptamer/small target binding events. A substantial enhancement in curcumin’s fluorescent emission was observed when bound into the grooves of vitamin D3 (VTD3) binding aptamer, as an example. However, the introduction of the target molecule causes the aptamer to undergo a conformational change that favors complexing the target molecule over binding the curcumin dye. The sensor was able to detect VTD3 down to 1 fM concentration in buffer solutions and extracted blood samples, operate at a wide dynamic range, and discriminate against potential biological interfering molecules including VTD2. The operation of the curcumin based fluorescent sensor is at least six orders of magnitude more sensitive than a VTD3 sensor constructed with the synthetic dye SYBR Green I. The generality of the reported label-free approach was applied with a previously isolated 75-mer bisphenol-A (BPA) aptamer, confirming that the reported sensing strategy is not confined on a particular aptamer sequence. Our work not only reports a novel sensor format for the detection of small molecules, but also serves fluorescent sensor’s most pressing need being novel fluorophores for multiplex targets detection.

Rapid Label-free Protein Detection Arrays on Coated Silicon Wafers

2006 ◽  
Vol 951 ◽  
Author(s):  
Christopher C. Striemer ◽  
Charles R. Mace ◽  
Benjamin L. Miller
Keyword(s):  
Dynamic Range ◽  
Direct Detection ◽  
Protein Detection ◽  
Ccd Camera ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Solution Concentration ◽  
Label Free ◽  
Probe Molecules ◽  
Target Binding

ABSTRACTWe are developing label-free Arrayed Imaging Reflectometry (AIR) for rapid and multiplexed protein detection. AIR is based on the high dynamic range in reflected optical intensity near a point of zero reflectance on an antireflection coated substrate. The reflectance is therefore highly sensitive to changes in film thickness, allowing direct detection of molecular binding when appropriate probe molecules are immobilized on the surface. The simplest implementation of AIR uses a 633 nm HeNe laser and a silicon wafer substrate coated with ∼1400 Å of SiO2. This system has a reflectance zero for s-polarized HeNe light incident at ∼70°. This interference film is then functionalized with probe molecules designed to bind to a specific target, and this binding can be detected with high sensitivity in the reflectance signal. By expanding the laser beam and collecting the reflected signal with a CCD camera, large arrays of detection spots can be imaged simultaneously. Spot intensity increases relative to the amount of target binding and the target solution concentration can then be calculated. We have demonstrated the detection of the Enteropathogenic E Coli membrane protein Intimin at levels below 10 pM using receptor molecule Tir as a probe, and are currently evaluating various clinical targets using more common antibody probes.

scholarly journals A Novel Graphene Oxide-Based Aptasensor for Amplified Fluorescent Detection of Aflatoxin M1 in Milk Powder

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3840 ◽  
Author(s):  
Xiaodong Guo ◽  
Fang Wen ◽  
Qinqin Qiao ◽  
Nan Zheng ◽  
Matthew Saive ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Milk Powder ◽  
High Sensitivity ◽  
High Specificity ◽  
Fluorescent Detection ◽  
Aflatoxin M1 ◽  
Powder Samples ◽  
Infant Milk Powder

In this paper, a rapid and sensitive fluorescent aptasensor for the detection of aflatoxin M1 (AFM1) in milk powder was developed. Graphene oxide (GO) was employed to quench the fluorescence of a carboxyfluorescein-labelled aptamer and protect the aptamer from nuclease cleavage. Upon the addition of AFM1, the formation of an AFM1/aptamer complex resulted in the aptamer detaching from the surface of GO, followed by the aptamer cleavage by DNase I and the release of the target AFM1 for a new cycle, which led to great signal amplification and high sensitivity. Under optimized conditions, the GO-based detection of the aptasensor exhibited a linear response to AFM1 levels in a dynamic range from 0.2 to 10 μg/kg, with a limit of detection (LOD) of 0.05 μg/kg. Moreover, the developed aptasensor showed a high specificity towards AFM1 without interference from other mycotoxins. In addition, the technique was successfully applied for the detection of AFM1 in infant milk powder samples. The aptasensor proposed here offers a promising technology for food safety monitoring and can be extended to various targets.

Monitoring of inflammatory response to cancer immunotherapies.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e15199-e15199 ◽  
Author(s):  
Qimin Quan ◽  
John Geanacopoulos ◽  
Joshua Ritchey ◽  
Mark Clenow ◽  
Joe Wilkinson ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Single Molecule ◽  
Dynamic Range ◽  
Color Change ◽  
High Sensitivity ◽  
Test Methods ◽  
Label Free ◽  
Cell Therapies ◽  
Color Changes ◽  
Cmos Compatible

e15199 Background: Inflammation observed in response to some monoclonal antibody drugs and adaptive T-Cell therapies has become a major issue in cancer immunotherapy. Prognostic monitoring of the inflammatory response requires simultaneous measurement of multiple cytokines at widely divergent concentrations. At present, no analytical method, known to us, can provide large dynamic range (> 6 logs), high sensitivity (< 1pg/ml) and high multiplex in a single test. Methods: The NanoMosaic platform is a cytokine quantification technology powered by silicon nanoneedle biosensors that are densely integrated on a plate and manufactured with CMOS-compatible nanofabrication processes. Each nanoneedle is a label-free biosensor, functionalized with capture antibodies. Each analyte specific sensing area consists a total of ~23k nanoneedles divided into a digital region (~20k nanoneedles) and an analog region (~3k nanoneedles), combined to cover the entire range of inflammatory biomarkers from 0.1pg/ml to 1ug/ml. Results: We demonstrated that the digital nanoneedles achieve the single molecule sensitivity. Therefore, at ultra-low concentrations when antigens that are captured by the nanoneedles follow Poisson statistics, the number of antigens can be quantitated by counting the presence or absence of color changes of individual nanoneedles in a binary fashion. As the protein concentrations increase, the binding events increase accordingly and achieve saturation when all nanoneedles capture more than one protein. Above the digital saturation concentration, an adjacent section of analog nanoneedles perform quantitative analysis based on the level of color change, thus providing a wider dynamic range up to 1ug/ml. Each single analyte area, including both digital and analog sensors, is less than 500um. Therefore, high level multiplex can be achieved by duplicating the detection sensor in a microarray format without loss of sensitivity and dynamic range. Conclusions: The CMOS-compatible NanoMosaic technology provides the cost-effectiveness, sensitivity, dynamic range and multiplexing capacity required to fully integrate patient immune response into therapeutic development and decision making.

scholarly journals Label-Free Catalytic and Molecular Beacon Containing an Abasic Site for Sensitive Fluorescent Detection of Small Inorganic and Organic Molecules

2012 ◽  
Vol 84 (6) ◽  
pp. 2916-2922 ◽  
Author(s):  
Panshu Song ◽  
Yu Xiang ◽  
Hang Xing ◽  
Zhaojuan Zhou ◽  
Aijun Tong ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Molecular Beacon ◽  
Fluorescent Detection ◽  
Label Free ◽  
Abasic Site ◽  
Inorganic And Organic

Slow-Scan CCD Observation of Backscattering Patterns in SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1308-1309
Author(s):  
F. Ouyang ◽  
D. A. Ray ◽  
O. L. Krivanek
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Lens System ◽  
Wide Dynamic Range ◽  
Peltier Cooler ◽  
Diffraction Patterns ◽  
Scanning Electron

Electron backscattering Kikuchi diffraction patterns (BKDP) reveal useful information about the structure and orientation of crystals under study. With the well focused electron beam in a scanning electron microscope (SEM), one can use BKDP as a microanalysis tool. BKDPs have been recorded in SEMs using a phosphor screen coupled to an intensified TV camera through a lens system, and by photographic negatives. With the development of fiber-optically coupled slow scan CCD (SSC) cameras for electron beam imaging, one can take advantage of their high sensitivity and wide dynamic range for observing BKDP in SEM.We have used the Gatan 690 SSC camera to observe backscattering patterns in a JEOL JSM-840A SEM. The CCD sensor has an active area of 13.25 mm × 8.83 mm and 576 × 384 pixels. The camera head, which consists of a single crystal YAG scintillator fiber optically coupled to the CCD chip, is located inside the SEM specimen chamber. The whole camera head is cooled to about -30°C by a Peltier cooler, which permits long integration times (up to 100 seconds).

Development of imaging plate for a TEM and its characteristics

1989 ◽  
Vol 47 ◽  
pp. 100-101
Author(s):  
N. Mori ◽  
T. Oikawa ◽  
Y. Harada ◽  
J. Miyahara ◽  
T. Matsuo
Keyword(s):  
Dynamic Range ◽  
Protective Layer ◽  
High Sensitivity ◽  
Imaging Plate ◽  
Phosphor Layer ◽  
Imaging Device ◽  
X Ray Imaging ◽  
New Type ◽  
Basic Characteristics ◽  
Reading System

The Imaging Plate (IP) is a new type imaging device, which was developed for diagnostic x ray imaging. We have reported that usage of the IP for a TEM has many merits; those are high sensitivity, wide dynamic range, and good linearity. However in the previous report the reading system was prototype drum-type-scanner, and IP was also experimentally made, which phosphor layer was 50μm thick with no protective layer. So special care was needed to handle them, and they were used only to make sure the basic characteristics. In this article we report the result of newly developed reading, printing system and high resolution IP for practical use. We mainly discuss the characteristics of the IP here. (Precise performance concerned with the reader and other system are reported in the other article.)Fig.1 shows the schematic cross section of the IP. The IP consists of three parts; protective layer, phosphor layer and support.

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