Detection of 5-hydroxymethylfurfural based on split-DNAzyme assisted signal amplification via quartz crystal microbalance

5-hydroxymethylfurfural (HMF) is one of the food contaminants mainly formed by Maillard and caramelization reaction. Here, we developed a simple method to detect HMF based on split-DNAzyme assisted signal amplification via Quartz crystal microbalance. Firstly, two fragments of the split-DNAzyme (ESCYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN I and ESII) and AuNPsssDNA were prepared. In the absence of HMF, the amino group of ESCYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN I reacted with the aldehyde group of ESCYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN ICYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN I by Schiff base condensation,which linked ESCYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN I and ESII as DNAzyme. With the help of Mg2+, this DNAzyme cleaved AuNPs-ssDNA, freeing the complementary sequence of capture DNA from the ssDNA. In the presence of the target HMF, the aldehyde group in its molecular structure preferred to react with ESCYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN I, which prevented the link of ESCYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN I and ESII. In this case, DNAzyme cannot be formed effectively and the ssDNA modified on AuNPs cannot be cleaved. Secondly, the capture DNA was immobilized on Au chip in the QCM chamber. Then, the intact AuNPsssDNA was introduced to hybridize with the capture DNA, resulted in a large frequency change (Delta F) of the QCM biosensor because of the huge increased mass of AuNPs. So, HMF can be detected based on the frequency change (Delta F) of the QCM biosensor. This QCM biosensor is more sensitive than previously reported methods, which provide a new direction for the analytical detection of HMF and other food contaminants.

Automated summary

A simple method to detect the food contaminant HMF was developed using split-DNAzyme and AuNPssssDNA for signal amplification via Quartz crystal microbalance. The method involves forming DNAzyme in absence of HMF, preventing DNAzyme formation in presence of HMF, and detecting HMF based on frequency change of QCM biosensor. This biosensor is more sensitive than previous methods for analytical detection of HMF and other food contaminants.