A rapid and highly selective paper-based device for high-throughput detection of cysteine with red fluorescence emission and a large Stokes shift

2019 ◽  
Vol 11 (10) ◽  
pp. 1312-1316 ◽  
Author(s):  
Jia Zhou ◽  
Changmin Yu ◽  
Zheng Li ◽  
Pingping Peng ◽  
Duoteng Zhang ◽  
...  
Keyword(s):  
High Throughput ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Fluorescent Emission ◽  
Red Fluorescence ◽  
Large Stokes Shift ◽  
High Throughput Detection

A paper-based device for high-throughput detection of cysteine with red fluorescent emission and large Stokes shift has been developed.

scholarly journals Large Stokes shift fluorescence activation in an RNA aptamer by intermolecular proton transfer to guanine

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mateusz Mieczkowski ◽  
Christian Steinmetzger ◽  
Irene Bessi ◽  
Ann-Kathrin Lenz ◽  
Alexander Schmiedel ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Base Pair ◽  
Fluorescent Proteins ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Rna Aptamers ◽  
Rna Aptamer ◽  
Time Resolved ◽  
Large Stokes Shift ◽  
Mechanistic Basis

AbstractFluorogenic RNA aptamers are synthetic functional RNAs that specifically bind and activate conditional fluorophores. The Chili RNA aptamer mimics large Stokes shift fluorescent proteins and exhibits high affinity for 3,5-dimethoxy-4-hydroxybenzylidene imidazolone (DMHBI) derivatives to elicit green or red fluorescence emission. Here, we elucidate the structural and mechanistic basis of fluorescence activation by crystallography and time-resolved optical spectroscopy. Two co-crystal structures of the Chili RNA with positively charged DMHBO+ and DMHBI+ ligands revealed a G-quadruplex and a trans-sugar-sugar edge G:G base pair that immobilize the ligand by π-π stacking. A Watson-Crick G:C base pair in the fluorophore binding site establishes a short hydrogen bond between the N7 of guanine and the phenolic OH of the ligand. Ultrafast excited state proton transfer (ESPT) from the neutral chromophore to the RNA was found with a time constant of 130 fs and revealed the mode of action of the large Stokes shift fluorogenic RNA aptamer.

scholarly journals An α-cyanostilbene derivative for the enhanced detection and imaging of amyloid fibril aggregates

2020 ◽  
Author(s):  
Nicholas. R Marzano ◽  
Kelly M Wray ◽  
Caitlin L Johnston ◽  
Bishnu P Paudel ◽  
Yuning Hong ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Amyloid Fibril ◽  
Spectral Characteristics ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Fibril Formation ◽  
Promising Alternative ◽  
Large Stokes Shift ◽  
Fibril Aggregates

AbstractThe aggregation of proteins into amyloid fibrils has been implicated in the pathogenesis of a variety of neurodegenerative diseases, including Alzheimer’s and Parkinson’s disease. Benzothiazole dyes such as Thioflavin T (ThT) are well characterised and widely used fluorescent probes for monitoring amyloid fibril formation. However, existing dyes lack sensitivity and specificity to oligomeric intermediates formed during fibril formation. In this work we describe the use of an α-cyanostilbene derivative with aggregation-induced emission properties (called ASCP) as a fluorescent probe for the detection of amyloid fibrils. Similar to ThT, ASCP is fluorogenic in the presence of amyloid fibrils and upon binding and excitation at 460 nm produces a red-shifted emission with a large Stokes shift of 145 nm. ASCP has a higher binding affinity to fibrillar α-synuclein than ThT and likely shares the same binding sites to amyloid fibrils. Importantly, ASCP was found to also be fluorogenic in the presence of amorphous aggregates and can detect oligomeric species formed early during aggregation. Moreover, ASCP can be used to visualise fibrils via Total Internal Reflection Fluorescence (TIRF) microscopy and, due to its large Stokes shift, simultaneously monitor the fluorescence emission of other labelled proteins following excitation with the same laser used to excite ASCP. Consequently, ASCP possesses enhanced and unique spectral characteristics compared to ThT that make it a promising alternative for the in vitro study of amyloid fibrils and the mechanisms by which they form.

scholarly journals Structure–fluorescence activation relationships of a large Stokes shift fluorogenic RNA aptamer

2019 ◽  
Author(s):  
Christian Steinmetzger ◽  
Irene Bessi ◽  
Ann-Kathrin Lenz ◽  
Claudia Höbartner
Keyword(s):  
Ligand Binding ◽  
Fluorescent Protein ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Titration Calorimetry ◽  
Rna Aptamer ◽  
Large Stokes Shift ◽  
Molecular Features ◽  
G Quadruplex ◽  
Derivatives Of

Abstract The Chili RNA aptamer is a 52 nt long fluorogen-activating RNA aptamer (FLAP) that confers fluorescence to structurally diverse derivatives of fluorescent protein chromophores. A key feature of Chili is the formation of highly stable complexes with different ligands, which exhibit bright, highly Stokes-shifted fluorescence emission. In this work, we have analyzed the interactions between the Chili RNA and a family of conditionally fluorescent ligands using a variety of spectroscopic, calorimetric and biochemical techniques to reveal key structure–fluorescence activation relationships (SFARs). The ligands under investigation form two categories with emission maxima of ∼540 or ∼590 nm, respectively, and bind with affinities in the nanomolar to low-micromolar range. Isothermal titration calorimetry was used to elucidate the enthalpic and entropic contributions to binding affinity for a cationic ligand that is unique to the Chili aptamer. In addition to fluorescence activation, ligand binding was also observed by NMR spectroscopy, revealing characteristic signals for the formation of a G-quadruplex only upon ligand binding. These data shed light on the molecular features required and responsible for the large Stokes shift and the strong fluorescence enhancement of red and green emitting RNA–chromophore complexes.

Fluorescence emission originated from the H-aggregated cyanine dye with chiral gemini surfactant assemblies having a narrow absorption band and a remarkably large Stokes shift

2017 ◽  
Vol 53 (63) ◽  
pp. 8870-8873 ◽  
Author(s):  
Naoya Ryu ◽  
Yutaka Okazaki ◽  
Emilie Pouget ◽  
Makoto Takafuji ◽  
Shoji Nagaoka ◽  
...  
Keyword(s):  
Absorption Band ◽  
Gemini Surfactant ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Cyanine Dye ◽  
Large Stokes Shift ◽  
Narrow Absorption Band

A cyanine dye formed chiral H-aggregates with a narrow absorption band on gemini surfactant chiral assemblies and showed fluorescence emission with a remarkably large Stokes shift.

scholarly journals High-Sensitivity High-Throughput Detection of Nucleic Acid Targets on Metasurface Fluorescence Biosensors

Biosensors ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 33
Author(s):  
Masanobu Iwanaga
Keyword(s):  
Nucleic Acid ◽  
High Throughput ◽  
High Performance ◽  
Direct Detection ◽  
Fluorescence Emission ◽  
High Sensitivity ◽  
Nanorod Array ◽  
Silicon On Insulator ◽  
Detection Methods ◽  
High Throughput Detection

Worldwide infection disease due to SARS-CoV-2 is tremendously affecting our daily lives. High-throughput detection methods for nucleic acids are emergently desired. Here, we show high-sensitivity and high-throughput metasurface fluorescence biosensors that are applicable for nucleic acid targets. The all-dielectric metasurface biosensors comprise silicon-on-insulator nanorod array and have prominent electromagnetic resonances enhancing fluorescence emission. For proof-of-concept experiment on the metasurface biosensors, we have conducted fluorescence detection of single-strand oligoDNAs, which model the partial sequences of SARS-CoV-2 RNA indicated by national infection institutes, and succeeded in the high-throughput detection at low concentrations on the order of 100 amol/mL without any amplification technique. As a direct detection method, the metasurface fluorescence biosensors exhibit high performance.

High-throughput Detection of Protein Kinase Activities in Cell Lysate Based on the Aggregation of Gold Nanoparticles with Peptides

2009 ◽  
Author(s):  
Yoshiki Katayama ◽  
Hirotaro Kitazaki ◽  
Jeong-Hun Kang ◽  
Xiaoming Han ◽  
Takeshi Mori ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Protein Kinase ◽  
High Throughput ◽  
Cell Lysate ◽  
High Throughput Detection
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