title: A molecular switch sensor for detection of PRSS1 genotype based on site-specific DNA cleavage of restriction endonuclease.
abstract: BACKGROUND
  PRSS1 mutations or polymorphism in the peripheral blood of patients can be used as susceptible molecular markers to pancreatic cancer. A sensor for selective electrochemical detection of PRSS1 genotypes was developed based on site-specific DNA cleavage of restriction endonuclease EcoRI.
  
  
  METHODS
  A mercapto-modified hairpin probe was immobilized on a gold electrode. The probe's neck can be cleaved by EcoRI in the absence of rs10273639 C/C of PRSS1 genotype, but it cannot be cleaved in the presence of T/T. The difference in quantity of electric charge was monitored by biosensors before and after enzymatic cleavage. Electrochemical signals are generated by differential pulse voltammetry interrogation of methylene blue (MB) that quantitatively binds to surface-confined hairpin probe via electrostatic interactions.
  
  
  RESULTS
  The results suggested this method had a good specificity in distinguishing PRSS1 genotypes. There was a good linear relationship between the charge and the logarithmic function of PRSS1 rs10273639 T/T type DNA concentration (current=120.6303+8.8512log C, R=0.9942). The detection limit was estimated at 0.5 fM.
  
  
  CONCLUSIONS
  The molecular switch sensor has several advantages, and it is possible to qualitatively, quantitatively, and noninvasively detect PRSS1 genotypes in the blood of patients with pancreatic cancer.
authors.affiliation: Department of Laboratory Medicine, the 1 Affiliated Hospital, Fujian Medical University.
authors.forename: Qicai
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Pathology, the 1 Affiliated Hospital, Fujian Medical University lqc673@aliyun.com fengfang77777@163.com.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.affiliation: Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, China.
authors.forename: Shaohuang
authors.initials: S
authors.lastname: Weng
authors.affiliation: Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, China.
authors.forename: Huaping
authors.initials: H
authors.lastname: Peng
authors.affiliation: Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, China.
authors.forename: Liqing
authors.initials: L
authors.lastname: Lin
authors.affiliation: Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, China.
authors.forename: Chengfei
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, China.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Lin
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis; D053837:DNA Cleavage; D004262:DNA Restriction Enzymes / Q000378:metabolism*; D058266:Dielectric Spectroscopy; D004566:Electrodes; D005838:Genotype; D060005:Genotyping Techniques; D006046:Gold; D006801:Humans; D012815:Signal Processing, Computer-Assisted; D014357:Trypsin / Q000235:genetics*
chemical_list: D006046:Gold; D004247:DNA; D004262:DNA Restriction Enzymes; C489303:PRSS1 protein, human; D014357:Trypsin
keywords: Molecular switch sensor; PRSS1 genotypes; noninvasive; pancreatic cancer; qualitatively and quantitatively; restriction endonuclease