**7. Others**

Zhao et al. [34] developed a novel nano-antibody and magnetic beads-based directed competitive ELISA (MB-dcELISA) based on both recombinant antibody and its mimotope for AFB1 detection. The 50% inhibition concentration and detection limit of MB-dcELISA were 0.75 and 0.13 ng/mL, respectively, and the linear range was 0.24–2.21 ng/mL.

Zhang et al. [35] discovered a novel anti-AFB1 monoclonal antibody in order to establish a sensitive immunoassay for AFB1, and a novel CdTe/CdS/ZnS quantum dot fluorescence probe was synthesized by binding to the surface of CdTe/CdS/ZnS quantum dots. CdTe/CdS/ZnS quantum dot is a kind of semiconductor nanomaterial, which has strong photostability and fluorescence efficiency and has longer fluorescence time. Compared with the traditional ELISA method, fluorescence immunoassays (FLISA) can be used to measure AFB1 in grain samples in a wide range of linearity. In addition, CdTe/CdS/ZnS quantum dot fluorescence assay has lower toxicity, high stability, and excellent fluorescence properties.

Based on the competitive response of AFB1 and cy5 modified DNA complementary strands to aptamers, Shim et al. [36] first developed a dipstick assay for AFB1 sensing. This sensor has a minimum detection limit of about 0.1 ng/mL for AFB1, indicating good potential for practical applications. The whole determination process can be completed in 30 min. Moreover, the dipstick assay is consistent with the ELISA assay results.

### **8. Discussion**

We mainly report on the new detection techniques of aflatoxin in recent years. It mainly includes fluorescence detection, electrochemical detection, immunological detection, and so on. Fluorescence detection method is more and more popular in the industry because of its high sensitivity and high specificity. Electrochemical detection is a powerful analytical technology. Due to its simple operation and low price, it has been widely used in environmental monitoring and food safety [30]. According to the different detection principles, it can be divided into electrochemical enzyme sensor, electrochemical immunosensor, and electrochemical aptamer sensor in the determination of aflatoxin in food. ELISA has been widely used in the determination of AFB1 in recent years. The method has high sensitivity and selectivity, but the reaction time is long and the operation process is complex. In addition, antibodies and enzymes are easily denatured during storage, which severely limits their practical application.

More and more scholars are committed to the research and development of highly sensitive AFB1 sensor [37], and biosensors with antibodies, enzymes, and nucleic acid aptamers as recognition elements were constructed. In addition, a large number of new materials have been used for the detection of AFB1 at home and abroad.

As the research frontier of modern science and technology, nanotechnology has been widely used in the detection of AFB1 abbreviation in foods in combination with electrophysiology, biology, and immunology and has become a development trend in the field of food safety research. The fabrication of Au nanostructures/ graphene nanosheets modified ITO substrate has been reported; it is then used as a high sensitivity and AFB1 sensor to detect very low concentrations of AFB1 early by using Raman spectroscopy and electrochemical techniques [38]. Carbon dots (C-dots), as a new type of fluorescent nanomaterials, have attracted great attention in recent years due to their excellent light stability, good biocompatibility, low toxicity, and good water solubility. In order to expand the field of application, many researchers have studied the surface modification of C-dots with various functions [28]. Compared to traditional fluorescent sensors, C-dots-based aptasensors have greater potential because of their chemical inertness, ease of functionalization, and resistance to photobleaching. Based on the highly efficient fluorescence quenching properties of AuNP, a DNA sensor for detecting mRNA in living cells was developed. The results show that the fluorescence sensor based on AuNPs leads to high signal and sensitivity. CdTe quantum dots have the advantages of high fluorescence yield, strong photostability, long fluorescence lifetime, good biocompatibility, and wide excitation wavelength range. It is widely used in biomedical fields such as biochips, protein and DNA detection, and targeted tracing [39–42].

**101**

**Author details**

Xing-Zhi-Zi Wang1,2

for Nationalities, Baise, China

\*Address all correspondence to: stpwxzz@163.com

provided the original work is properly cited.

Nationalities, Baise, China

*A New Approach for Detection of Aflatoxin B1 DOI: http://dx.doi.org/10.5772/intechopen.90403*

most promising for the detection of AFB1.

response.

However, nanotechnology itself has its drawbacks. The preparation of CdS nanoparticles and CoOOH nanosheets takes a long time, and it is necessary to verify whether the synthesis is successful. In addition, the concentration of CdS nanoparticles directly affects PEC immunosensor; excessive CdS may lead to high background signal, whereas a low concentration produces a weak photocurrent

As an important medium, aptamer combines AFB1 with nanomaterials and detects it by fluorescence and electrophysiological detection, which greatly shortens the time of detection and reduces the cost, and its accuracy and reliability. There is no change in sex, and the specificity and sensitivity are increased. However, since the AFB1 aptamer preparation technique may still need improvement, as described above, the AFB1 aptamer is an oligonucleotide, and the length of the small molecule nucleotide affects the binding to AFB1. Aptamer Structure Switch coupled with horseradish peroxidase labeling on microplate for sensitive detection of small molecules. It is affected by the concentration of aptamer and AFB1, and the results of Ye [24] show that when only 10 nM aptamer is used, the change in FP and AFB1 concentrations has a good linear relationship between 0.05 and 5 nM of AFB1. Coupled with the time required for preparation, combined with the complex and diverse detection methods, there is no standardized operation in life. However, based on the fluorescence and electrochemical detection of the AFB1 aptamer, it is

1 Department of Pathology, The Affiliated Hospital of Youjiang Medical University

2 The Centre of Pathology Diagnosis and Research, Youjiang Medial University for

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

#### *A New Approach for Detection of Aflatoxin B1 DOI: http://dx.doi.org/10.5772/intechopen.90403*

*Aflatoxin B1 Occurrence, Detection and Toxicological Effects*

the ELISA assay results.

**8. Discussion**

abroad.

quantum dots. CdTe/CdS/ZnS quantum dot is a kind of semiconductor nanomaterial, which has strong photostability and fluorescence efficiency and has longer fluorescence time. Compared with the traditional ELISA method, fluorescence immunoassays (FLISA) can be used to measure AFB1 in grain samples in a wide range of linearity. In addition, CdTe/CdS/ZnS quantum dot fluorescence assay has

Based on the competitive response of AFB1 and cy5 modified DNA complementary strands to aptamers, Shim et al. [36] first developed a dipstick assay for AFB1 sensing. This sensor has a minimum detection limit of about 0.1 ng/mL for AFB1, indicating good potential for practical applications. The whole determination process can be completed in 30 min. Moreover, the dipstick assay is consistent with

We mainly report on the new detection techniques of aflatoxin in recent years. It mainly includes fluorescence detection, electrochemical detection, immunological detection, and so on. Fluorescence detection method is more and more popular in the industry because of its high sensitivity and high specificity. Electrochemical detection is a powerful analytical technology. Due to its simple operation and low price, it has been widely used in environmental monitoring and food safety [30]. According to the different detection principles, it can be divided into electrochemical enzyme sensor, electrochemical immunosensor, and electrochemical aptamer sensor in the determination of aflatoxin in food. ELISA has been widely used in the determination of AFB1 in recent years. The method has high sensitivity and selectivity, but the reaction time is long and the operation process is complex. In addition, antibodies and enzymes are easily denatured during storage, which severely limits their practical application. More and more scholars are committed to the research and development of highly sensitive AFB1 sensor [37], and biosensors with antibodies, enzymes, and nucleic acid aptamers as recognition elements were constructed. In addition, a large number of new materials have been used for the detection of AFB1 at home and

As the research frontier of modern science and technology, nanotechnology has been widely used in the detection of AFB1 abbreviation in foods in combination with electrophysiology, biology, and immunology and has become a development trend in the field of food safety research. The fabrication of Au nanostructures/ graphene nanosheets modified ITO substrate has been reported; it is then used as a high sensitivity and AFB1 sensor to detect very low concentrations of AFB1 early by using Raman spectroscopy and electrochemical techniques [38]. Carbon dots (C-dots), as a new type of fluorescent nanomaterials, have attracted great attention in recent years due to their excellent light stability, good biocompatibility, low toxicity, and good water solubility. In order to expand the field of application, many researchers have studied the surface modification of C-dots with various functions [28]. Compared to traditional fluorescent sensors, C-dots-based aptasensors have greater potential because of their chemical inertness, ease of functionalization, and resistance to photobleaching. Based on the highly efficient fluorescence quenching properties of AuNP, a DNA sensor for detecting mRNA in living cells was developed. The results show that the fluorescence sensor based on AuNPs leads to high signal and sensitivity. CdTe quantum dots have the advantages of high fluorescence yield, strong photostability, long fluorescence lifetime, good biocompatibility, and wide excitation wavelength range. It is widely used in biomedical fields such as

biochips, protein and DNA detection, and targeted tracing [39–42].

lower toxicity, high stability, and excellent fluorescence properties.

**100**

However, nanotechnology itself has its drawbacks. The preparation of CdS nanoparticles and CoOOH nanosheets takes a long time, and it is necessary to verify whether the synthesis is successful. In addition, the concentration of CdS nanoparticles directly affects PEC immunosensor; excessive CdS may lead to high background signal, whereas a low concentration produces a weak photocurrent response.

As an important medium, aptamer combines AFB1 with nanomaterials and detects it by fluorescence and electrophysiological detection, which greatly shortens the time of detection and reduces the cost, and its accuracy and reliability. There is no change in sex, and the specificity and sensitivity are increased. However, since the AFB1 aptamer preparation technique may still need improvement, as described above, the AFB1 aptamer is an oligonucleotide, and the length of the small molecule nucleotide affects the binding to AFB1. Aptamer Structure Switch coupled with horseradish peroxidase labeling on microplate for sensitive detection of small molecules. It is affected by the concentration of aptamer and AFB1, and the results of Ye [24] show that when only 10 nM aptamer is used, the change in FP and AFB1 concentrations has a good linear relationship between 0.05 and 5 nM of AFB1. Coupled with the time required for preparation, combined with the complex and diverse detection methods, there is no standardized operation in life. However, based on the fluorescence and electrochemical detection of the AFB1 aptamer, it is most promising for the detection of AFB1.
