scholarly journals A Label-Free Liquid Crystal Biosensor Based on Specific DNA Aptamer Probes for Sensitive Detection of Amoxicillin Antibiotic

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 370
Author(s):  
Duy Khiem Nguyen ◽  
Chang-Hyun Jang
Keyword(s):  
Liquid Crystal ◽  
Specific Binding ◽  
Water Environment ◽  
Polarized Light ◽  
High Specificity ◽  
Dna Aptamer ◽  
Sensitive Detection ◽  
Label Free ◽  
Homeotropic Orientation ◽  
Optical Appearance

We developed a liquid crystal (LC) aptamer biosensor for the sensitive detection of amoxicillin (AMX). The AMX aptamer was immobilized onto the surface of a glass slide modified with a mixed self-assembled layer of dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DMOAP) and (3-aminopropyl) triethoxysilane (APTES). The long alkyl chains of DMOAP maintained the LC molecules in a homeotropic orientation and induced a dark optical appearance under a polarized light microscope (POM). In the presence of AMX, the specific binding of the aptamer and AMX molecules induced a conformational change in the aptamers, leading to the disruption of the homeotropic orientation of LCs, resulting in a bright optical appearance. The developed aptasensor showed high specificity and a low detection limit of 3.5 nM. Moreover, the potential application of the developed aptasensor for the detection of AMX in environmental samples was also demonstrated. Therefore, the proposed aptasensor is a promising platform for simple, rapid, and label-free monitoring of AMX in an actual water environment with high selectivity and sensitivity.

scholarly journals A liquid-crystal-based DNA biosensor for pathogen detection

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Mashooq Khan ◽  
Abdur Rahim Khan ◽  
Jae-Ho Shin ◽  
Soo-Young Park
Keyword(s):  
Liquid Crystal ◽  
Pathogen Detection ◽  
Grid Cell ◽  
High Specificity ◽  
Erwinia Carotovora ◽  
Optical Microscope ◽  
Label Free ◽  
Label Free Detection ◽  
Homeotropic Orientation ◽  
Tem Grid

Abstract A liquid-crystal (LC)-filled transmission electron microscopy (TEM) grid cell coated with the cationic surfactant dodecyltrimethylammonium bromide (DTAB), to which a single-stranded deoxyribonucleic acid probe (ssDNAprobe) was adsorbed at the LC/aqueous interface (TEMDTAB/DNA), was applied for the highly specific detection of target DNA molecules. The DTAB-coated E7 (used LC mixture) in the TEM grid (TEMDTAB) exhibited a homeotropic orientation, and changed to a planar orientation upon adsorption of the ssDNAprobe. The TEMDTAB/DNA was then exposed to complementary (target) ssDNA, which resulted in a planar-to-homeotropic configurational change of E7 that could be observed through a polarized optical microscope under crossed polarizers. The optimum adsorption density (2 μM) of ssDNAprobe enabled the detection of ≥0.05 nM complementary ssDNA. This TEMDTAB/DNA biosensor could differentiate complementary ssDNA from mismatched ssDNA as well as double-stranded DNA. It also successfully detected the genomic DNAs of the bacterium Erwinia carotovora and the fungi Rhazictonia solani. Owe to the high specificity, sensitivity, and label-free detection, this biosensor may broaden the applications of LC-based biosensors to pathogen detection.

scholarly journals A Cationic Surfactant-Decorated Liquid Crystal-Based Aptasensor for Label-Free Detection of Malathion Pesticides in Environmental Samples

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 92
Author(s):  
Duy Khiem Nguyen ◽  
Chang-Hyun Jang
Keyword(s):  
Liquid Crystal ◽  
Cationic Surfactant ◽  
Environmental Samples ◽  
Tap Water ◽  
High Specificity ◽  
Optical Image ◽  
Label Free ◽  
Optical Images ◽  
Label Free Detection ◽  
Homeotropic Orientation

We report a liquid crystal (LC)-based aptasensor for the detection of malathion using a cationic surfactant-decorated LC interface. In this method, LCs displayed dark optical images when in contact with aqueous cetyltrimethylammonium bromide (CTAB) solution due to the formation of a self-assembled CTAB monolayer at the aqueous/LC interface, which induced the homeotropic orientation of LCs. With the addition of malathion aptamer, the homeotropic orientation of LCs changed to a planar one due to the interactions between CTAB and the aptamer, resulting in a bright optical image. In the presence of malathion, the formation of aptamer-malathion complexes caused a conformational change of the aptamers, thereby weakening the interactions between CTAB and the aptamers. Therefore, CTAB is free to induce a homeotropic ordering of the LCs, which corresponds to a dark optical image. The developed sensor exhibited high specificity for malathion determination and a low detection limit of 0.465 nM was achieved. Moreover, the proposed biosensor was successfully applied to detect malathion in tap water, river water, and apple samples. The proposed LC-based aptasensor is a simple, rapid, and convenient platform for label-free monitoring of malathion in environmental samples.

Cds nanocrystal enhanced TiO2photoelectrochemical aptasensor for sensitive detection of cytochrome c

2021 ◽  
Vol 11 (11) ◽  
pp. 1774-1780
Author(s):  
Shanji Fan ◽  
Hong Huang ◽  
Hong Chen ◽  
Jiachi Xu ◽  
Zecheng Hu ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Limit Of Detection ◽  
Specific Binding ◽  
High Sensitivity ◽  
High Specificity ◽  
Linear Range ◽  
Current Intensity ◽  
Sensitive Detection ◽  
Layer Adsorption ◽  
Ionic Layer

A CdS nanocrystal enhanced TiO2 nanotubes (CdS@TiO2 NATs) photoelectrode was prepared via successive ionic layer adsorption and reaction (SILAR) of CdS on the surface of TiO2 NATs. A HS-aptamer owing a specific binding toward cytochrome c was modified onto the CdS@TiO2 NATs, which resulting a decrease in the photoelectrical current intensity. Cytochrome c is therefore quantified based on the decrease in photoelectrical current. High specificity and high sensitivity were obtained with a linear range from 3 pM to 80 nM, and a limit of detection of 2.53 pM.

Label-free sensitive detection of MUC1 using a liquid crystal based-system

2020 ◽  
Vol 47 (12) ◽  
pp. 1784-1793 ◽  
Author(s):  
Thai Duong Song Duong ◽  
Chang-Hyun Jang
Keyword(s):  
Liquid Crystal ◽  
Sensitive Detection ◽  
Label Free

A novel, label-free liquid crystal biosensor for Parkinson's disease related alpha-synuclein

2020 ◽  
Vol 56 (40) ◽  
pp. 5441-5444
Author(s):  
Xiuxiu Yang ◽  
Haiyu Li ◽  
Xiaofang Zhao ◽  
Wei Liao ◽  
Claire Xi Zhang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Liquid Crystal ◽  
Parkinson Disease ◽  
Alpha Synuclein ◽  
Dna Aptamer ◽  
Label Free

A novel, label-free liquid crystal biosensor for the detection of Parkinson disease related alpha-synuclein based on DNA aptamer was constructed.

Simple, Rapid and Sensitive Detection of Parkinson's Disease Related Alpha-Synuclein by DNA Aptamer Assisted Liquid Crystal Biosensor

Soft Matter ◽  
2021 ◽  
Author(s):  
Zhongqiang Yang ◽  
Xiuxiu Yang ◽  
Xiaofang Zhao ◽  
Fengwei Liu ◽  
Haiyu Li ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Liquid Crystal ◽  
Alpha Synuclein ◽  
Dna Aptamer ◽  
Sensitive Detection ◽  
Potential Biomarker

Alpha-synuclein (αS) has been proposed as a potential biomarker for diagnosis of Parkinson's disease (PD). However, detection of αS in a simple, rapid and sensitive approach is still challenging. Herein,...

Recent Advances on Therapeutic Peptides for Breast Cancer Treatment

2020 ◽  
Vol 21 ◽  
Author(s):  
Samad Beheshtirouy ◽  
Farhad Mirzaei ◽  
Shirin Eyvazi ◽  
Vahideh Tarhriz
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Breast Cancer Cells ◽  
Specific Binding ◽  
High Specificity ◽  
The Novel ◽  
Anti Cancer ◽  
Therapeutic Peptides ◽  
Low Toxicity

: Breast cancer is a heterogeneous malignancy which is the second cause of mortality among women in the world. Increasing the resistance to anti-cancer drugs in breast cancer cells persuades researchers to search the novel therapies approaches for the treatment of the malignancy. Among the novel methods, therapeutic peptides which target and disrupt tumor cells have been of great interest. Therapeutic peptides are short amino acids monomer chains with high specificity to bind and modulate a protein interaction of interest. Several advantages of peptides such as specific binding on tumor cells surface, low molecular weight and low toxicity on normal cells make the peptides as an appealing therapeutic agents against solid tumors, particularly breast cancer. Also, National Institutes of Health (NIH) describes therapeutic peptides as suitable candidate for the treatment of drug-resistant breast cancer. In this review, we attempt to review the different therapeutic peptides against breast cancer cells which can be used in treatment and diagnosis of the malignancy. Meanwhile, we presented an overview of peptide vaccines which have been developed for the treatment of breast cancer.

scholarly journals DNA Aptamer Functionalized Hydrogels for Interferometric Fiber-Optic Based Continuous Monitoring of Potassium Ions

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 266
Author(s):  
Nataša Žuržul ◽  
Bjørn Torger Stokke
Keyword(s):  
Conformational Transition ◽  
Polymer Network ◽  
Potassium Ion ◽  
Ion Concentration ◽  
Dna Aptamer ◽  
Blood Levels ◽  
Label Free ◽  
Practical Applications ◽  
Hydrogel Matrix ◽  
K Concentration

In the present paper, we describe a potassium sensor based on DNA-aptamer functionalized hydrogel, that is capable of continuous label-free potassium ion (K+) monitoring with potential for in situ application. A hydrogel attached to the end of an optical fiber is designed with di-oligonucleotides grafted to the polymer network that may serve as network junctions in addition to the covalent crosslinks. Specific affinity toward K+ is based on exploiting a particular aptamer that exhibits conformational transition from single-stranded DNA to G-quadruplex formed by the di-oligonucleotide in the presence of K+. Integration of this aptamer into the hydrogel transforms the K+ specific conformational transition to a K+ concentration dependent deswelling of the hydrogel. High-resolution interferometry monitors changes in extent of swelling at 1 Hz and 2 nm resolution for the hydrogel matrix of 50 µm. The developed hydrogel-based biosensor displayed high selectivity for K+ ions in the concentration range up to 10 mM, in the presence of physiological concentrations of Na+. Additionally, the concentration dependent and selective K+ detection demonstrated in the artificial blood buffer environment, both at room and physiological temperatures, suggests substantial potential for practical applications such as monitoring of potassium ion concentration in blood levels in intensive care medicine.

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