Qinxin Song

Professor

Research：Biopharmaceutical Analysis
Tel：
E-mail：songqinxin@cpu.edu.cn
Office：Room 234, College Experimental Building
Laboratory：Room 223, College Experimental Building

1. Research Projects

(1)The National Natural Science Foundation of China (Grant No. 21005088)

(2)The National Natural Science Foundation of China (Grant No. 81673390)

(3)The National Natural Science Foundation of China (Grant No. 82173780)

(4)Jiangsu province social development project of scientific and technical supporting programs (Grant No.BE2012744)

(5)Jiangsu province social development project of scientific and technical supporting programs (Grant No.BE2016745)

(6)The Natural Science Foundation of Jiangsu Province (Grant No. BK2008067)

(7)The Natural Science Foundation of Jiangsu Province (Grant No. BK20151445)

(8)The Natural Science Foundation of Jiangsu Province (Grant No. BK20191322)

(9)General Financial Grant from the China Postdoctoral Science Foundation (Grant No. 2012M512179)

(10)Special Financial Grant from the China Postdoctoral Science Foundation (Grant No.2013T60962)

2. Academic Awards

2009, third Prize for Science & Technology Development of Jiangsu Province of China, 4/5

2010, first Prize for Science & Technology Development of Yunnan Province of China, 7/10

2011, 9th natural science award for outstanding dissertation of Nanjing, 1/1

2014, first Prize for Science & technology Development/Achievement of the Ministry of Education, 3/9

2016, second Prize for Education scientific research achievement of Jiangsu Province of China, 1/6

3. Representative Research Achievements

(1)DNA walkers have shown superior performance in biosensing due to their programmability to design molecular walking behaviors with specific responses to different biological targets. However, it is still challenging to make DNA walkers capable of distinguishing DNA targets with single-base differences, so that DNA walkers that can be used for circulating tumor DNA sensing are rarely reported. Herein, a flap endonuclease 1 (FEN 1)-assisted DNA walker has been proposed to achieve mutant biosensing. The target DNA is captured on a gold nanoparticle (AuNP) as a walking strand to walk by hybridizing to the track strands on the surface of the AuNP. FEN 1 is employed to report the walking events by cleaving the track strands that must form a three-base overlapping structure recognized by FEN 1 after hybridizing with the captured target DNA. Owing to the high specificity of FEN 1 for structure recognition, the one-base mutant DNA target can be discriminated from wild-type DNA. By constructing a sensitivity-enhanced DNA walker system, as low as 1 fM DNA targets and 0.1% mutation abundance can be sensed, and the theoretical detection limits for detecting the DNA target and mutation abundance achieve 0.22 fM and 0.01%, respectively. The results of epidermal growth factor receptor (EGFR) L858R mutation detection on cell-free DNA samples from 15 patients with non-small cell lung cancer were completely consistent with that of next-generation sequencing, indicating that our DNA walker has potential for liquid biopsy.

(2)Cervical cancer is the fourth leading cause of death in women, especially in developing countries. Specific and economic methodologies for HPV typing are crucial in cancer diagnosis and further disease control. However, routine assays based on real-time polymerase chain reaction (qPCR) or DNA-chip hybridization are either incapable of offering detailed subtype information or involve tedious open-tube operations with the risk of cross-contamination from PCR amplicons. Herein, we proposed a multiplex visualized closed-tube PCR (Multi-Vision) for HPV typing. Using gold nanoparticle probes (AuNPs) as a color change indicator combined with a Hamming distance 2 coding scheme, 13 high-risk HPVs and two subtypes associated with high-incidence benign lesions were successfully typed by performing six closed-tube PCRs. The assay demonstrates high specificity with no cross-reaction among different subtypes under several artificial sample concentrations (from 100 to 103 copies per reaction) and enables highly sensitive detection of as low as 0.5 copies/μL. Further, 105 clinical samples were successfully analyzed using our method with a high concordance rate of 99.05% (104/105) compared to HPV typing kit. The inconsistent sample was confirmed by sequencing to be consistent with the typing results determined by our method, indicating that Multi-Vision could be a useful tool for HPV detection, especially in resource-limited regions.

(3)Digital PCR (dPCR) is one of the most accurate and reliable tools for the examination of genetic alterations in liquid biopsy. The sensitivity of dPCR relies on the partition numbers for dPCR. The challenge is to achieve an ultra-sensitive dPCR without increasing the reaction units. Herein, we proposed the use of invasive reaction to pick up amplified mutants co-existing with many wild-type amplicons at each dPCR reaction unit (termed as Invader-dPCR). As invasive reaction is highly specific in one-base recognition, a 1000-fold sensitivity improvement for mutation detection was achieved in a conventional dPCR platform. As a result, the sample loading could be greatly increased without the increase of the number of dPCR reaction units. For cost-effective detection, we extended the Invader-dPCR to a “multiplex” detection model by using different signal-intensity groups to replace different dyes for identifying multiple targets, allowing the construction of a logic sensor to detect multiple mutants related to personalized medicine. The logic sensor was successfully used to guide the precise use of gefitinib by detecting 17 kinds of drug-sensitive and drug-resistant mutations simultaneously. Invader-dPCR was well validated for both the ultra-sensitive and multiplexed detection, and successfully applied to the detection of clinical samples.