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Published on: November 20, 2013
Ultrasensitive biosensor based on MXene-GO field-effect transistor for the rapid detection of endotoxin and
Hale Alvandi1, Farina Asadi1, Ali Hossein Rezayan1
1Department of Nanobiotechnology and Biomimetics, School of Bioengineering, College of Interdisciplinary Science and Technology, University of Tehran, Tehran, Iran.
Background:
Sepsis is known as one of the deadliest and costliest diseases in the world, which can be caused by bacteria or toxins and affects more than 30 million people annually. Similar clinical symptoms and the lack of a specific laboratory test have challenged its diagnosis and treatment. The fast, accurate, and easy detection of sepsis pathogens such as E. coli using biosensors is essential. Here, a Field-effect-Transistor aptasensor based on MXene and graphene oxide (MXene-GO-Apt FET) was designed and fabricated for the whole cell of E. coli and its endotoxin (lipopolysaccharide) detection.
Results:
MXene (Ti3C2) was prepared by HF etching of Ti3AlC2, and its composite was synthesized with GO. After the ATR-FTIR, XRD, EDX, and FESEM characterization and biosensor fabrication, the amino ssDNA aptamer was immobilized on the biosensor surface. The investigation of the drain-source current showed that the biosensor modification with MXene-GO composite results in suitable and stable electrical conductivity. E. coli detection occurs by binding aptamer to lipopolysaccharides in the outer membrane of bacteria, changing its conformation, and then reducing the biosensor current. The response of the biosensor was highly selective; its detection limit was 1 pg/ml and 3 CFU/ml for lipopolysaccharide and E. coli in PBS buffer and better compared to other studies. MXene-GO-Apt FET's response is stable after 30 days and detects endotoxin and E. coli in human blood serum without pretreatment to 10 ng/ml and 30 CFU/ml, respectively, in 300s.
Significance And Novelty:
This study represents a MXene-GO-Apt FET nanobiosensor for detecting E. coli and its endotoxin in PBS buffer and human blood serum in 300s. The small sample volume required and the possibility of performing by an unskilled user with accurate and ultrasensitive detection of bacteria and its LPS are the advantages of MXene-GO-Apt FET, which can be used as a point-of-care sensor for detecting pathogens in patients.
Insights
A novel MXene-GO-Apt FET biosensor offers rapid and sensitive detection of E. coli and its endotoxin, crucial for diagnosing sepsis. This Field-effect-Transistor aptasensor provides a potential point-of-care solution for pathogen detection.
Area of Science:
- Nanotechnology
- Biosensors
- Materials Science
Background:
- Sepsis affects over 30 million people annually, posing a significant global health challenge.
- Current sepsis diagnosis is hindered by similar clinical symptoms and lack of specific tests.
- Fast and accurate detection of pathogens like E. coli is essential for effective sepsis management.
Purpose of the Study:
- To design and fabricate a Field-effect-Transistor aptasensor (MXene-GO-Apt FET) for detecting E. coli and its endotoxin (lipopolysaccharide).
- To evaluate the biosensor's sensitivity, selectivity, stability, and performance in biological samples.
Main Methods:
- Preparation of MXene and its composite with graphene oxide (GO).
- Immobilization of amino ssDNA aptamer on the MXene-GO composite surface.
- Fabrication of the Field-effect-Transistor aptasensor and characterization of its electrical properties.
Main Results:
- The MXene-GO composite provided stable electrical conductivity for the biosensor.
- The MXene-GO-Apt FET demonstrated high selectivity for E. coli and lipopolysaccharide.
- Achieved detection limits of 1 pg/ml for lipopolysaccharide and 3 CFU/ml for E. coli in PBS buffer.
- The biosensor maintained stability for 30 days and detected endotoxin and E. coli in human blood serum within 300 seconds.
Conclusions:
- The developed MXene-GO-Apt FET nanobiosensor enables rapid, accurate, and ultrasensitive detection of E. coli and its endotoxin.
- The biosensor requires a small sample volume and can be operated by unskilled users.
- This technology holds promise as a point-of-care sensor for timely pathogen detection in sepsis patients.
