Intrinsic fluorescence–based label-free detection of bovine amyloid A amyloidosis

2021 ◽  
pp. 104063872110492
Author(s):  
Naoki Ujike ◽  
Susumu Iwaide ◽  
Yuki Ono ◽  
Takayuki Okano ◽  
Tomoaki Murakami
Keyword(s):  
Analytical Data ◽  
Principal Component ◽  
Histochemical Staining ◽  
Intrinsic Fluorescence ◽  
Label Free ◽  
Simple Method ◽  
Spectrometry Analysis ◽  
Amyloid A ◽  
Label Free Detection ◽  
Tissue Homogenates

Amyloidosis is diagnosed by the histologic detection of amyloid deposits; however, this method has limitations such as a prolonged diagnosis time and the need for histologic proficiency. We aimed to develop a rapid and simple method for diagnosing amyloidosis by targeting amyloid-specific endogenous fluorescence, which has not been reported previously, to our knowledge. Fluorescence fingerprint analysis of amyloid extracts and tissue homogenates derived from amyloid A (AA) amyloidosis-affected cattle exhibited a specific intrinsic fluorescence pattern. Furthermore, principal component analysis using analytical data revealed that AA could be identified by peaks near λex 350 nm and λem 430 nm. Fluorescence spectrometry analysis using tissue homogenates, which does not require special histochemical staining, enables the rapid detection of bovine AA.

scholarly journals Harnessing intrinsic fluorescence for typing of secondary structures of DNA

2020 ◽  
Author(s):  
Michela Zuffo ◽  
Aurélie Gandolfini ◽  
Brahim Heddi ◽  
Anton Granzhan
Keyword(s):  
High Throughput ◽  
Conformational Changes ◽  
Emission Spectra ◽  
Principal Component ◽  
Secondary Structures ◽  
Intrinsic Fluorescence ◽  
Label Free ◽  
Linear Discriminant ◽  
Effective Manner

ABSTRACTDNA is polymorphic since, despite its ubiquitous presence as a double-stranded helix, it is able to fold into a plethora of other secondary structures both in vitro and in cells. Despite the considerable advances that have been made in understanding this structural diversity, its high-throughput investigation still faces severe limitations. This mainly stems from the lack of suitable label-free methods, combining a fast and cheap experimental workflow with high information content. Here, we explore the use of intrinsic fluorescence emitted by nucleic acids for this scope. After a preliminary assessment of the suitability of this phenomenon for tracking the conformational changes of DNA, we examined the intrinsic steady-state emission spectra of an 89-membered set of synthetic oligonucleotides with reported conformation (G-quadruplexes, i-motifs, single- and double stranded DNA) by means of multivariate analysis. Specifically, principal component analysis of emission spectra resulted in successful clustering of oligonucleotides into three corresponding conformational groups, albeit without discrimination between single- and double-stranded structures. Linear discriminant analysis of the same training set was exploited for the assessment of new sequences, allowing the evaluation of their G4-forming propensity. Our method does not require any labelling agent or dye, avoiding the related intrinsic bias, and can be utilized to screen novel sequences of interest in a high-throughput and cost-effective manner. In addition, we observed that left-handed (Z-) G4 structures were systematically more fluorescent than most other G4 structures, almost reaching the quantum yield of 5′-d[(G3T)3G3]-3′ (G3T), the most fluorescent G4 structure reported to date. This property is likely to arise from the similar base-stacking geometry in both types of structures.

scholarly journals Metal-Enhanced Intrinsic Fluorescence of Proteins on Silver Nanostructured Surfaces toward Label-Free Detection

2008 ◽  
Vol 112 (46) ◽  
pp. 17957-17963 ◽  
Author(s):  
Krishanu Ray ◽  
Mustafa H. Chowdhury ◽  
Henryk Szmacinski ◽  
Joseph R. Lakowicz
Keyword(s):  
Intrinsic Fluorescence ◽  
Label Free ◽  
Nanostructured Surfaces ◽  
Label Free Detection

scholarly journals Rapid label-free SERS detection of foodborne pathogenic bacteria based on hafnium ditelluride-Au nanocomposites

2020 ◽  
Vol 13 (05) ◽  
pp. 2041004 ◽  
Author(s):  
Yang Li ◽  
Yanxian Guo ◽  
Binggang Ye ◽  
Zhengfei Zhuang ◽  
Peilin Lan ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Limit Of Detection ◽  
Principal Component ◽  
High Sensitivity ◽  
Chemical Mechanism ◽  
Sers Substrate ◽  
Label Free ◽  
Label Free Detection ◽  
Surface Enhanced Raman ◽  
Foodborne Pathogenic Bacteria

Two-dimensional (2D) nanomaterials have captured an increasing attention in biophotonics owing to their excellent optical features. Herein, 2D hafnium ditelluride (HfTe[Formula: see text], a new member of transition metal tellurides, is exploited to support gold nanoparticles fabricating HfTe2-Au nanocomposites. The nanohybrids can serve as novel 2D surface-enhanced Raman scattering (SERS) substrate for the label-free detection of analyte with high sensitivity and reproducibility. Chemical mechanism originated from HfTe2 nanosheets and the electromagnetic enhancement induced by the hot spots on the nanohybrids may largely contribute to the superior SERS effect of HfTe2-Au nanocomposites. Finally, HfTe2-Au nanocomposites are utilized for the label-free SERS analysis of foodborne pathogenic bacteria, which realize the rapid and ultrasensitive Raman test of Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Salmonella with the limit of detection of 10 CFU/mL and the maximum Raman enhancement factor up to [Formula: see text]. Combined with principal component analysis, HfTe2-Au-based SERS analysis also completes the bacterial classification without extra treatment.

scholarly journals Harnessing intrinsic fluorescence for typing of secondary structures of DNA

2020 ◽  
Vol 48 (11) ◽  
pp. e61-e61 ◽  
Author(s):  
Michela Zuffo ◽  
Aurélie Gandolfini ◽  
Brahim Heddi ◽  
Anton Granzhan
Keyword(s):  
Nucleic Acids ◽  
High Throughput ◽  
Conformational Changes ◽  
Emission Spectra ◽  
Principal Component ◽  
Structural Diversity ◽  
Intrinsic Fluorescence ◽  
Label Free ◽  
Linear Discriminant ◽  
Effective Manner

Abstract High-throughput investigation of structural diversity of nucleic acids is hampered by the lack of suitable label-free methods, combining fast and cheap experimental workflow with high information content. Here, we explore the use of intrinsic fluorescence emitted by nucleic acids for this scope. After a preliminary assessment of suitability of this phenomenon for tracking conformational changes of DNA, we examined steady-state emission spectra of an 89-membered set of oligonucleotides with reported conformation (G-quadruplexes (G4s), i-motifs, single- and double-strands) by means of multivariate analysis. Principal component analysis of emission spectra resulted in successful clustering of oligonucleotides into three corresponding conformational groups, without discrimination between single- and double-stranded structures. Linear discriminant analysis was exploited for the assessment of novel sequences, allowing the evaluation of their G4-forming propensity. Our method does not require any labeling agent or dye, avoiding the related bias, and can be utilized to screen novel sequences of interest in a high-throughput and cost-effective manner. In addition, we observed that left-handed (Z-) G4 structures were systematically more fluorescent than most other G4 structures, almost reaching the quantum yield of 5′-d[(G3T)3G3]-3′ (G3T, the most fluorescent G4 structure reported to date).

Label-free detection of biotoxins via a photo-induced force infrared spectrum at the single-molecular level

The Analyst ◽  
2019 ◽  
Vol 144 (20) ◽  
pp. 6108-6117 ◽  
Author(s):  
Bin Ji ◽  
Ahmad Kenaan ◽  
Shan Gao ◽  
Jin Cheng ◽  
Daxiang Cui ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Infrared Spectrum ◽  
Single Molecule ◽  
Molecular Level ◽  
Principal Component ◽  
Component Analysis ◽  
Label Free ◽  
Force Microscopy ◽  
Label Free Detection

Schematic illustration of photo-induced force microscopy combine principal component analysis detected and distinguish single molecule particles of biotoxins AT, RT/ETX with label-free.

scholarly journals Graphene oxide assisted light-up aptamer selection against Thioflavin T for label-free detection of microRNA

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Md Mamunul Islam ◽  
Victoria Michele Ghielmetti ◽  
Peter B. Allen
Keyword(s):  
Graphene Oxide ◽  
Limit Of Detection ◽  
Low Cost ◽  
Micro Rna ◽  
Thioflavin T ◽  
Label Free ◽  
Strand Displacement Amplification ◽  
Simple Method ◽  
Modified Dna ◽  
Label Free Detection

AbstractWe selected an aptamer against a fluorogenic dye called Thioflavin T (ThT). Aptamers are single-stranded DNA that can bind a specific target. We selected the ThT aptamer using graphene oxide assisted SELEX and a low-cost Open qPCR instrument. We optimized, minimized, and characterized the best aptamer candidate against ThT. The aptamer, ThT dye, and the enzymatic strand displacement amplification (SDA) were used in a label-free approach to detect the micro RNA miR-215 in saliva and serum. The aptamer confers higher specificity than intercalating dyes but without expensive covalently modified DNA probes. This isothermal, low-cost, simple method can detect both DNA and RNA. The target, miR-215, was detected with a limit of detection of 2.6 nM.

scholarly journals The Role of Surface Chemistry in the Efficacy of Protein and DNA Microarrays for Label-Free Detection: An Overview

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1026
Author(s):  
Elisa Chiodi ◽  
Allison M. Marn ◽  
Matthew T. Geib ◽  
M. Selim Ünlü
Keyword(s):  
Surface Chemistry ◽  
Surface Functionalization ◽  
Dna Microarrays ◽  
Label Free ◽  
Polymeric Coatings ◽  
Label Free Detection ◽  
Particle Imaging ◽  
Single Particle Imaging ◽  
The Impact

The importance of microarrays in diagnostics and medicine has drastically increased in the last few years. Nevertheless, the efficiency of a microarray-based assay intrinsically depends on the density and functionality of the biorecognition elements immobilized onto each sensor spot. Recently, researchers have put effort into developing new functionalization strategies and technologies which provide efficient immobilization and stability of any sort of molecule. Here, we present an overview of the most widely used methods of surface functionalization of microarray substrates, as well as the most recent advances in the field, and compare their performance in terms of optimal immobilization of the bioreceptor molecules. We focus on label-free microarrays and, in particular, we aim to describe the impact of surface chemistry on two types of microarray-based sensors: microarrays for single particle imaging and for label-free measurements of binding kinetics. Both protein and DNA microarrays are taken into consideration, and the effect of different polymeric coatings on the molecules’ functionalities is critically analyzed.

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