A self-monitored fluorescence DNA anti-counterfeiting system based on silica coated SYBR Green I/DNA gelatin nanoparticles

Abstract

A novel strategy was developed to prepare silica-coated SYBR Green I (SG)/DNA gelatin nanoparticles (SSDG NPs) for fabricating a self-monitored anti-counterfeiting system. In this system, definite DNA was first entwined with positively charged gelatin to form DNA-loaded gelatin nanoparticles (DG NPs) in acid solution by electrostatic interaction. After changing the DG NPs surface charge to negative by adjusting the pH to neutral, positively charged SG was adsorbed by the electrostatic interaction and high affinity with DNA. Finally, DG NPs were coated with silica to protect the DNA. The SSDG NPs are stable and resistant to DNA degradation. The fluorescence is stable under extreme environments, such as acidic and basic solutions, high temperature and salt, oxidation, exogenous DNA, and photobleaching. The SSDG NPs-based anti-counterfeiting label is stable under the weather test, with a shelf-life of longer than one year. The activity of encapsulated DNA was self-monitored by fluorescence of SG, which can also realize rapidly nondestructive DNA detection for anti-counterfeiting. Further accurate detection was carried out by agarose gel electrophoresis of PCR amplification and even DNA sequencing. The system offers good potential for anti-counterfeiting and long-term DNA storage.