Photobleaching of Fluorescent Dyes under Conditions Used for Single-Molecule Detection:  Evidence of Two-Step Photolysis

1998 ◽  
Vol 70 (13) ◽  
pp. 2651-2659 ◽  
Author(s):  
C. Eggeling ◽  
J. Widengren ◽  
R. Rigler ◽  
C. A. M. Seidel
Author(s):  
D. S. Park ◽  
B. B. Lowrey ◽  
C. R. Brown ◽  
B. H. You ◽  
V. Singh ◽  
...  

A polymer-based, multiplex single molecule detection module (SMD) was developed with a fluidic substrate and a cover plate. The fluidic substrate was fabricated using a single-step, double-sided hot embossing in poly(methyl methacrylate) (PMMA) with sampling zone microchannels on the bottom side and microlenses on the top. Shallow sampling zone microchannels (5 μm deep and 100 μm wide) were made to improve sampling efficiency and microlenses were adopted to collect the fluorescent radiation from the sampling zone microchannels. A cyclic olefin copolymer (COC) embedded waveguide in PMMA along with an integrated coupling prism was fabricated using polydimethylsiloxane (PDMS) stencils and melted COC (40% w/v in toluene) on the cover plate. The COC waveguide with a COC integrated coupling prism will be used for evanescent excitation of fluorescent samples in the sampling zone microchannels. The fluidic substrate was bonded with the cover plate using thermal fusion bonding based on a pressure-assisted boiling point control system. This approach allowed for sealing of shallow microchannels without observable sagging of the cover plate, which was confirmed by leakage testing with fluorescent dyes. The completed SMD module will be tested for characterization of the optical performances such as signal-to-noise ratio and sampling efficiency and it will provide the capability for rapid screening of stroke at low cost.


2021 ◽  
Author(s):  
Li-juan Wang ◽  
Le Liang ◽  
Bing-jie Liu ◽  
BingHua Jiang ◽  
Chun-yang Zhang

A controlled T7 transcription-driven symmetric amplification cascade machinery is developed for single-molecule detection of multiple repair glycosylases.


Author(s):  
Xiaojia Jiang ◽  
Mingsong Zang ◽  
Fei Li ◽  
Chunxi Hou ◽  
Quan Luo ◽  
...  

Biological nanopore-based techniques have attracted more and more attention recently in the field of single-molecule detection, because they allow the real-time, sensitive, high-throughput analysis. Herein, we report an engineered biological...


Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1942
Author(s):  
Xiaoqing Zeng ◽  
Yang Xiang ◽  
Qianshan Liu ◽  
Liang Wang ◽  
Qianyun Ma ◽  
...  

Protein is an important component of all the cells and tissues of the human body and is the material basis of life. Its content, sequence, and spatial structure have a great impact on proteomics and human biology. It can reflect the important information of normal or pathophysiological processes and promote the development of new diagnoses and treatment methods. However, the current techniques of proteomics for protein analysis are limited by chemical modifications, large sample sizes, or cumbersome operations. Solving this problem requires overcoming huge challenges. Nanopore single molecule detection technology overcomes this shortcoming. As a new sensing technology, it has the advantages of no labeling, high sensitivity, fast detection speed, real-time monitoring, and simple operation. It is widely used in gene sequencing, detection of peptides and proteins, markers and microorganisms, and other biomolecules and metal ions. Therefore, based on the advantages of novel nanopore single-molecule detection technology, its application to protein sequence detection and structure recognition has also been proposed and developed. In this paper, the application of nanopore single-molecule detection technology in protein detection in recent years is reviewed, and its development prospect is investigated.


1994 ◽  
Vol 33 (Part 1, No. 3A) ◽  
pp. 1571-1576 ◽  
Author(s):  
Mitsuru Ishikawa ◽  
Ken-ichi Hirano ◽  
Tsuyoshi Hayakawa ◽  
Shigeru Hosoi ◽  
Sydney Brenner

Author(s):  
Hsin-Chih Yeh ◽  
Christopher M. Puleo ◽  
Yi-Ping Ho ◽  
Tza-Huei Wang

In this report, we review several single-molecule detection (SMD) methods and newly developed nanocrystal-mediated single-fluorophore strategies for ultrasensitive and specific analysis of genomic sequences. These include techniques, such as quantum dot (QD)-mediated fluorescence resonance energy transfer (FRET) technology and dual-color fluorescence coincidence and colocalization analysis, which allow separation-free detection of low-abundance DNA sequences and mutational analysis of oncogenes. Microfluidic approaches developed for use with single-molecule detection to achieve rapid, low-volume, and quantitative analysis of nucleic acids, such as electrokinetic manipulation of single molecules and confinement of sub-nanoliter samples using microfluidic networks integrated with valves, are also discussed.


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