A rapid and visual aptasensor for Lipopolysaccharides detection based on the bulb-like triplex turn-on switch coupled with HCR-HRP nanostructures.
For previously reported aptasensor, the sensitivity and selectivity of aptamers to targets were often suppressed due to the reporter label of single-stranded molecular beacon or hindrance of the duplex DNA strand displacement. To solve the affinity declining of aptamers showed in traditional way and realize on-site rapid detection of Lipopolysaccharides (LPS), we developed an ingenious structure-switching aptasensor based on the bulb-like triplex turn-on switch (BTTS) as the effective molecular recognition and signal transduction element and streptavidin-horseradish peroxidase modified hybridization chain reaction (HCR-HRP) nanocomposites as the signal amplifier and signal report element. In the presence of LPS, the bulb-like LPS-aptamer (BLA) and LPS formed the LPS/aptamer complex, while the BTTS disassembled and liberated the dissociative bridge probes (BP) to achieve molecular recognition and signal transduction. Immobilized BP, captured by immobilized capture probes (CP), triggered hybridization chain reactions (HCR) to amplify the switching signal, and the HCR products were then modified with streptavidin-horseradish peroxidase (SA-HRP) to form HCR-HRP nanostructures to output colorimetric signals. In less than four hours, the proposed biosensor showed a detection limit of 50pg/mL of LPS quantitatively with the portable spectrophotometer and the observation limit of 20ng/mL semi-quantitatively with the naked eye, opening up new opportunities for LPS detection in future clinical diagnosis, food security and environment monitoring.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China; Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
Wentao
W
Xu
Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
Jingjing
J
Tian
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
Xiangli
X
Shao
Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
Longjiao
L
Zhu
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China; Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
Kunlun
K
Huang
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China. Electronic address: lyb@cau.edu.cn.
Yunbo
Y
Luo
D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D003124:Colorimetry / Q000379:methods; D060766:Drinking Water / Q000382:microbiology*; D004926:Escherichia coli / Q000737:chemistry / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000097:blood; D006735:Horseradish Peroxidase / Q000737:chemistry; D006801:Humans; D008070:Lipopolysaccharides / Q000032:analysis* / Q000097:blood*; D049329:Nanostructures / Q000737:chemistry*; D009693:Nucleic Acid Hybridization / Q000379:methods; D051381:Rats
D052157:Aptamers, Nucleotide; D060766:Drinking Water; D008070:Lipopolysaccharides; C440499:lipopolysaccharide, Escherichia coli O111 B4; D006735:Horseradish Peroxidase
Aptasensor; DNA triplex; Hybridization chain reaction; Lipopolysaccharides; Visual