Tailoring Conformation-Induced Chromism of Polythiophene Copolymers for Nucleic Acid Assay at Resource Limited Settings

Rajwar, Deepa; Ammanath, Gopal; Cheema, Jamal Ahmed; Palaniappan, Alagappan; Yıldız, Ümit Hakan; Liedberg, Bo

doi:10.1021/acsami.5b12171

Cited by 24 publications

(33 citation statements)

References 32 publications

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“…In case of addition of noncomplementary miR, the interaction between the negative charges of the nucleic acids and the positively charged PT results in the formation of miR:PT planar adducts, quenching the PT fluorescence and causing a visible color-shift from orange to pink. Later, the same group reported the application of PT copolymers (cPT) for miR-21 detection in plasma, reporting an LOD of 10 nM without the use of expensive instrumentation for the read-out [110].…”

Section: Colorimetric Assays Based On Hybridizationmentioning

confidence: 99%

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PNA-Based MicroRNA Detection Methodologies

2020

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MicroRNAs (miRNAs or miRs) are small noncoding RNAs involved in the fine regulation of post-transcriptional processes in the cell. The physiological levels of these short (20–22-mer) oligonucleotides are important for the homeostasis of the organism, and therefore dysregulation can lead to the onset of cancer and other pathologies. Their importance as biomarkers is constantly growing and, in this context, detection methods based on the hybridization to peptide nucleic acids (PNAs) are gaining their place in the spotlight. After a brief overview of their biogenesis, this review will discuss the significance of targeting miR, providing a wide range of PNA-based approaches to detect them at biologically significant concentrations, based on electrochemical, fluorescence and colorimetric assays.

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Section: Colorimetric Assays Based On Hybridizationmentioning

confidence: 99%

“…(B) Detection based on the peroxidase-like activity of graphene-AuNP nanohybrids shown in[107]. (C) Colorimetric/fluorescence-based detection of miR, relying on cPT:PNA:miR triplex formation, as described in[110].…”

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confidence: 99%

PNA-Based MicroRNA Detection Methodologies

2020

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“…The synthesis and NMR characterization of the synthesized polymers (Fig. 1) have been reported previously [30].…”

Section: Synthesis Of Pt With Varying Pendant Groupsmentioning

confidence: 99%

Tuning pendant groups of polythiophene on carbon nanotubes for vapour classification

Svm

Alahakoon

et al. 2017

Sensors and Actuators B: Chemical

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Poly(3-alkoxythiophene) (PT) with varying ratios of triethylamine and 1-methyl imidazole pendant groups and horizontally aligned single walled carbon nanotubes (SWCNT) are utilized in this study for volatile organic compounds (VOCs) classification. PTs with five different ratios of pendant groups are incorporated with SWCNT and are evaluated as chemiresistor arrays for analysis of VOCs such as ethanol, acetone, toluene, chloroform, isoprene and ethylene. Varying PT pendant groups yielded differential SWCNT current responses attributed to their chemical affinities for the VOCs tested. Principal component analysis (PCA) for vapour classification illustrated that the vapour responses are separable, thus, highlighting vapour discrimination ability of SWCNT with controlled ratios of PT pendant groups. The proposed methodology is a facile VOC classification approach for two main reasons; (i) PT could easily modified with various pendants groups containing appropriate chemical moieties for preferential interaction with various VOCs and (ii) increasing the number PTs with appropriate pendant group modifications would provide additional inputs to PCA thereby enabling capturing and assaying of a wide range of VOCs.

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“…Naked eye perceivable colorimetric responses were obtained at clinically relevant concentration ranges upon addition of mir21 in buffer solutions [23]. In a subsequent study, the colorimetric responses were evaluated by an image processing software that enabled quantification of nucleic acids in plasma samples [24]. Other reports for detection of oligonucleotide which are related to Middle East Respiratory Syndrome coronavirus (MERS-CoV), mycobacterium tuberculosis (MTB) and human papillomavirus (HPV) also indicate the potential applications for paper based sensors [25].…”

Section: Introductionmentioning

confidence: 99%

Pixelated colorimetric nucleic acid assay

Aydın

Cheema

Ammanath

et al. 2020

Talanta

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A B S T R A C TConjugated polyelectrolytes (CPEs) have been widely used as reporters in colorimetric assays targeting nucleic acids. CPEs provide naked eye detection possibility by their superior optical properties however, as concentration of target analytes decrease, trace amounts of nucleic acid typically yield colorimetric responses that are not readily perceivable by naked eye. Herein, we report a pixelated analysis approach for correlating colorimetric responses of CPE with nucleic acid concentrations down to 1 nM, in plasma samples, utilizing a smart phone with an algorithm that can perform analytical testing and data processing. The detection strategy employed relies on conformational transitions between single stranded nucleic acid-cationic CPE duplexes and double stranded nucleic acid-CPE triplexes that yield distinct colorimetric responses for enabling naked eye detection of nucleic acids. Cationic poly[N,N,N-triethyl-3-((4-methylthiophen-3-yl)oxy)propan-1-aminium bromide] is utilized as the CPE reporter deposited on a polyvinylidene fluoride (PVDF) membrane for nucleic acid assay. A smart phone application is developed to capture and digitize the colorimetric response of the individual pixels of the digital images of CPE on the PVDF membrane, followed by an analysis using the algorithm. The proposed pixelated approach enables precise quantification of nucleic acid assay concentrations, thereby eliminating the margin of error involved in conventional methodologies adopted for interpretation of colorimetric responses, for instance, RGB analysis. The obtained results illustrate that a ubiquitous smart phone could be utilized for point of care colorimetric nucleic acids assays in complex matrices without requiring sophisticated software or instrumentation.

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Tailoring Conformation-Induced Chromism of Polythiophene Copolymers for Nucleic Acid Assay at Resource Limited Settings

Cited by 24 publications

References 32 publications

PNA-Based MicroRNA Detection Methodologies

PNA-Based MicroRNA Detection Methodologies

Tuning pendant groups of polythiophene on carbon nanotubes for vapour classification

Pixelated colorimetric nucleic acid assay

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