Gold Nanoparticles Enhanced Microcantilever Sensors For Ions And Small Molecules Detection

With the advantages of small size, high sensitivity, high selectivity, label free,and easy to integrate with microfluid chip, microcantilever has been widely used inbiosensing applications, In this paper, we integrated gold nanoparticle and dynamicmicrocantilever sensor,and developed a sensing platform based on the decrease orincrease of the resonance frequency. Two researches are summarized as follows:1. An ultrasensitive microcantilever biosensor for small molecular melaminedetection based on the decrease of the resonance frequency was developed.Firstly, the DNA1probe was modified onto the microcantilever. Secondly, theDNA2-AuNPs were captured on the surface of the microcantilever by T-melamine-Tcomplex, which cause the sharply decrease of the resonance frequency, so we canrealize the ultrasensitive detection of melamine. In this system, the sensor has a goodsensitivity, the limit of detection is as low as of40fM （that is1.6amol）, which is3-6orders lower than the previous research. And this sensor has good selectivity for milksample detection, with a recovery of93%-110%.2. An ultrasensitive microcantilever biosensor for iodide detection based on theincrease of the resonance frequency was developed.Firstly, the DNA1probe was modified onto the microcantilever, then, AuNPscould be captured onto the microcantilever surface through T-Hg²⁺-T complex.Because Iodide could rob the Hg²⁺out of the T-Hg²⁺-T complex, resulting in theAuNPs leave the microcantilever and the the resonance frequency sharply increase. Inthis system, the sensor has a good sensitivity, and the limit of detection is27pM （thatis3.5ng/L）, which is3orders lower than the previous research. In addition, thissensor has good selectivity, it can quantify the iodine in the solution with highconcentration of chloride, getting a detection result consistent with the classicnational standard.