Novel multifunction-integrated molecular beacon for the amplification detection of DNA hybridization based on primer/template-free isothermal polymerization

• A multifunctional molecular beacon (MI-MB) was developed by integrating various elements into one MB.
• The MI-MB leads to the strand displacement amplification (SDA) resulting in signal amplification.
• Target DNA could be quantified down to subnanomolar level, and mutated DNA is capable of being detected.
• MI-MB is expected to promote the DNA probe application in clinical diagnosis and biomedical fields.

Molecular beacon (MB) is widely explored as a signaling probe in powerful biosensing systems, for example, enzyme-assisted strand displacement amplification (SDA)-based system. The existing polymerization-based amplification system is often composed of recognition element, primer, template and fluorescence reporter. To develop a new MB sensing system and simply the signal amplification design, we herein attempted to propose a multifunctional integrated MB (MI-MB) for the polymerization amplification detection of target DNA via introducing a G-rich fragment into the loop of MB without using any exogenous auxiliary oligonucleotide probe. Utilizing only one MI-MB probe, the p53 target gene could trigger the cycles of hybridization/polymerization/displacement, resulting in amplification of the target hybridization event. Thus, the p53 gene can be detected down to 5×10−10 M with the linear response range from 5×10−10 M to 4×10−7 M. Using the MI-MB, we could readily discriminate the point mutation-contained p53 from the wild-type one. As a proof-of-concept study, owing to its simplicity and multifunction, including recognition, replication, amplification and signaling, the MI-MB exhibits the great potential for the development of different biosensors for various biomedical applications, especially, for early cancer diagnosis.