Aptamer-Tethered DNA Origami Amplifier for Sensitive and Accurate Imaging of Intracellular MicroRNAs

Nanoscale ◽  
2021 ◽  
Author(s):  
Chao Xing ◽  
Shan Chen ◽  
Qitian Lin ◽  
Yuhong Lin ◽  
Min Wang ◽  
...  
Keyword(s):  
Living Cells ◽  
Dna Origami ◽  
Cell Binding ◽  
Diagnosis And Prognosis ◽  
Accurate Detection ◽  
Enzyme Degradation ◽  
Accurate Imaging

Accurate detection and imaging of low-abundant microRNAs (miRNAs) in living cells are essential for diagnosis and prognosis of diseases. Designing nanoprobes with resistance to enzyme degradation and effective cell-binding as...

Wrapped for Accurate Imaging

2011 ◽  
Vol 19 (4) ◽  
pp. 8-10
Author(s):  
Stephen W. Carmichael ◽  
Philip Oshel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Living Cells ◽  
Harsh Environment ◽  
Native State ◽  
Transmission Electron ◽  
Traditional Sense ◽  
Modified Graphene ◽  
Accurate Imaging ◽  
Fixed Beam

Since transmission electron microscopy (TEM) was developed about 80 years ago, numerous strategies have been attempted to visualize living cells at high resolution. The harsh environment within the TEM (mostly the vacuum and damage from a fixed beam of electrons) presents challenges. Some approaches have been to fabricate chambers within the TEM that provide a more “friendly” environment for living cells (that is, less stringent vacuum), but they have limitations. Impressive images have been generated with various cryogenic techniques, but frozen cells are not alive or in their native state in the traditional sense. Nihar Mohanty, Monica Fahrenholtz, Ashvin Nagaraja, Daniel Boyle, and Vikas Berry have developed an ingenious solution to the problem by “wrapping” cells with modified graphene.

Regulation of cell binding and entry by DNA origami mediated spatial distribution of aptamers

2020 ◽  
Vol 8 (31) ◽  
pp. 6802-6809 ◽  
Author(s):  
Ke Liu ◽  
Cong Xu ◽  
Jinyao Liu
Keyword(s):  
Spatial Distribution ◽  
Cancer Cells ◽  
Dna Origami ◽  
Cell Binding

Customizing the spatial distribution of aptamers on DNA origami nanoboxes can regulate the internalization and proliferation of cancer cells.

scholarly journals Current and Developing Technologies for Monitoring Agents of Bioterrorism and Biowarfare

2005 ◽  
Vol 18 (4) ◽  
pp. 583-607 ◽  
Author(s):  
Daniel V. Lim ◽  
Joyce M. Simpson ◽  
Elizabeth A. Kearns ◽  
Marianne F. Kramer
Keyword(s):  
Public Health ◽  
Nucleic Acid ◽  
Evanescent Wave ◽  
Living Cells ◽  
Innovative Technologies ◽  
The Public ◽  
Accurate Detection ◽  
Detection And Identification ◽  
Complex Sample ◽  
Public Health Officials

SUMMARY Recent events have made public health officials acutely aware of the importance of rapidly and accurately detecting acts of bioterrorism. Because bioterrorism is difficult to predict or prevent, reliable platforms to rapidly detect and identify biothreat agents are important to minimize the spread of these agents and to protect the public health. These platforms must not only be sensitive and specific, but must also be able to accurately detect a variety of pathogens, including modified or previously uncharacterized agents, directly from complex sample matrices. Various commercial tests utilizing biochemical, immunological, nucleic acid, and bioluminescence procedures are currently available to identify biological threat agents. Newer tests have also been developed to identify such agents using aptamers, biochips, evanescent wave biosensors, cantilevers, living cells, and other innovative technologies. This review describes these current and developing technologies and considers challenges to rapid, accurate detection of biothreat agents. Although there is no ideal platform, many of these technologies have proved invaluable for the detection and identification of biothreat agents.

Fluorescence ratio imaging of dynamic intracellular ionic signals

1988 ◽  
Vol 46 ◽  
pp. 42-43
Author(s):  
R. Y. Tsien ◽  
A. Minta ◽  
M. Poenie ◽  
J.P.Y. Kao ◽  
A. Harootunian
Keyword(s):  
Binding Sites ◽  
Living Cells ◽  
Molecular Engineering ◽  
Ph Indicators ◽  
Highly Sensitive ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Technical Advances ◽  
Indicator Dyes ◽  
Fluorescein Dyes

Recent technical advances now enable the continuous imaging of important ionic signals inside individual living cells with micron spatial resolution and subsecond time resolution. This methodology relies on the molecular engineering of indicator dyes whose fluorescence is strong and highly sensitive to ions such as Ca2+, H+, or Na+, or Mg2+. The Ca2+ indicators, exemplified by fura-2 and indo-1, derive their high affinity (Kd near 200 nM) and selectivity for Ca2+ to a versatile tetracarboxylate binding site3 modeled on and isosteric with the well known chelator EGTA. The most commonly used pH indicators are fluorescein dyes (such as BCECF) modified to adjust their pKa's and improve their retention inside cells. Na+ indicators are crown ethers with cavity sizes chosen to select Na+ over K+: Mg2+ indicators use tricarboxylate binding sites truncated from those of the Ca2+ chelators, resulting in a more compact arrangement of carboxylates to suit the smaller ion.

Application of FRAP and digitized fluorescence microscopy to problems in cell membrane dynamics

1988 ◽  
Vol 46 ◽  
pp. 118-119
Author(s):  
K. Jacobson ◽  
A. Ishihara ◽  
B. Holifield ◽  
F. Zhang
Keyword(s):  
Fluorescence Microscopy ◽  
Cell Biology ◽  
Extended Period ◽  
Dynamic Structure ◽  
Living Cells ◽  
Membrane Dynamics ◽  
Molecular Cell Biology ◽  
Image Averaging ◽  
Single Living Cells ◽  
Single Living

Our laboratory is concerned with understanding the dynamic structure of the plasma membrane with particular reference to the movement of membrane constituents during cell locomotion. In addition to the standard tools of molecular cell biology, we employ both fluorescence recovery after photo- bleaching (FRAP) and digitized fluorescence microscopy (DFM) to investigate individual cells. FRAP allows the measurement of translational mobility of membrane and cytoplasmic molecules in small regions of single, living cells. DFM is really a new form of light microscopy in that the distribution of individual classes of ions, molecules, and macromolecules can be followed in single, living cells. By employing fluorescent antibodies to defined antigens or fluorescent analogs of cellular constituents as well as ultrasensitive, electronic image detectors and video image averaging to improve signal to noise, fluorescent images of living cells can be acquired over an extended period without significant fading and loss of cell viability.

Multimode light microscopy and fluorescence-based reagents as tools for the study of chemical and molecular dynamics of living cells and tissues

1992 ◽  
Vol 50 (1) ◽  
pp. 418-419
Author(s):  
D. L. Taylor
Keyword(s):  
Living Cells ◽  
Cellular Level ◽  
Molecular Techniques ◽  
Cellular Functions ◽  
Macromolecular Assemblies ◽  
Cell Functions ◽  
Molecular Events ◽  
Yield Information ◽  
Full Knowledge ◽  
Structural Methods

Cells function through the complex temporal and spatial interplay of ions, metabolites, macromolecules and macromolecular assemblies. Biochemical approaches allow the investigator to define the components and the solution chemical reactions that might be involved in cellular functions. Static structural methods can yield information concerning the 2- and 3-D organization of known and unknown cellular constituents. Genetic and molecular techniques are powerful approaches that can alter specific functions through the manipulation of gene products and thus identify necessary components and sequences of molecular events. However, full knowledge of the mechanism of particular cell functions will require direct measurement of the interplay of cellular constituents. Therefore, there has been a need to develop methods that can yield chemical and molecular information in time and space in living cells, while allowing the integration of information from biochemical, molecular and genetic approaches at the cellular level.

4-dimensional, high-resolution imaging of living cells

1992 ◽  
Vol 50 (1) ◽  
pp. 416-417
Author(s):  
Shinya Inoué
Keyword(s):  
Light Microscope ◽  
Living Cells ◽  
Live Cells ◽  
Video Tape ◽  
Active Living ◽  
High Resolution Imaging ◽  
3 Dimensional ◽  
Dynamic Architecture ◽  
Resolution Imaging ◽  
Disk Memory

This paper reports progress of our effort to rapidly capture, and display in time-lapsed mode, the 3-dimensional dynamic architecture of active living cells and developing embryos at the highest resolution of the light microscope. Our approach entails: (A) real-time video tape recording of through-focal, ultrathin optical sections of live cells at the highest resolution of the light microscope; (B) repeat of A at time-lapsed intervals; (C) once each time-lapsed interval, an image at home focus is recorded onto Optical Disk Memory Recorder (OMDR); (D) periods of interest are selected using the OMDR and video tape records; (E) selected stacks of optical sections are converted into plane projections representing different view angles (±4 degrees for stereo view, additional angles when revolving stereos are desired); (F) analysis using A - D.

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