▎ 摘　　要

NOVELTY - A thionine functionalized reduced graphene oxide/hydrotalcite-like electrochemical DNA sensor comprises a gold electrode as base electrode and a thionine functionalized and reduced graphene oxide/hydrotalcite-like composite film as an electrode modification material. The probe DNA is fixed on the surface of the modified electrode through electrostatic interaction and non-valent bond interaction. The thionine functionalized and reduced graphene oxide/hydrotalcite-like composite film is prepared by derivatizing a hydrotalcite-like compound with a zeolitic imidazolate framework-67 template, compounding with graphene oxide through electrostatic interaction and reducing the thionine functionalization and hydrazine hydrate graphene oxide/hydrotalcite-like composite, electrode, and incubating at 25-70 degrees C for 2 hour to obtain the finished product. USE - Thionine functionalized reduced graphene oxide/hydrotalcite-like electrochemical DNA sensor for use in detection of Vibrio parahaemolyticus. ADVANTAGE - The thionine functionalized reduced graphene oxide/hydrotalcite-like electrochemical DNA sensor has better sensitivity and selectivity, low detection limit and wide linear range. DETAILED DESCRIPTION - A thionine functionalized reduced graphene oxide/hydrotalcite-like electrochemical DNA sensor comprises a gold electrode as base electrode and a thionine functionalized and reduced graphene oxide/hydrotalcite-like composite film as an electrode modification material. The probe DNA is fixed on the surface of the modified electrode through electrostatic interaction and non-valent bond interaction. The thionine functionalized and reduced graphene oxide/hydrotalcite-like composite film is prepared by derivatizing a hydrotalcite-like compound with a zeolitic imidazolate framework-67 template, compounding with graphene oxide through electrostatic interaction and reducing the thionine functionalization and hydrazine hydrate graphene oxide/hydrotalcite-like composite, where the hydrotalcite-like type is a cobalt-aluminum type hydrotalcite. The thionine-functionalized reduced graphene oxide/hydrotalcite-based electrochemical DNA sensors is prepared by dissolving 720 mg cobalt(II) nitrate hexahydrate and 20 mg cetrimonium bromide in 50 mL methanol solution and adding 50 mL 2-methylimidazole-methanol solution having a concentration of 32 mg/mL under stirring at 25-60 degrees C for 15 minutes, collecting the precipitate by centrifugation, washing with water and methanol three times in sequence, weighing 40 mg zeolitic imidazolate framework-67 in 20 mL ethanol and sonicating for 30 minutes, dissolving 50-200 mg aluminum nitrate nonahydrate in 10 mL ethanol and slowly adding to the solution under stirring to obtain mixture, stirring the mixture at 50-150 degrees C and refluxing for 1.5 hours, slowly turning the purple solution to pale pink to obtain precipitate, collecting the precipitate by centrifugation and washing with ethanol to obtain cobalt aluminum hydrotalcite, dispersing a certain amount of the graphene oxide in deionized water and dispersing ultrasonically for 2 hour to obtain a graphene oxide dispersion with a concentration of 1.0 mg/mL, dispersing 20 mg cobalt aluminum hydrotalcite in 20 mL water to obtain dispersion, adding 10 mL graphene oxide dispersion to the dispersion and stirred for 1 hour to obtain precipitate, collecting the precipitate by centrifugation, washing with water and absolute ethanol to obtain graphene oxide hydrotalcite complex, mixing 50 mL of 0.1-0.5 mg/mL graphene oxide hydrotalcite solution and 10 mL thionine solution with a concentration of 2 mM and stirring at room temperature for 16 hours, adding 200 mu L of 80% hydrazine monohydrate solution and stirring for 10 minutes, collecting the black precipitate by centrifugation, washing with deionized water and drying at room temperature to obtain thionine functionalized reducing graphene oxide hydrotalcite, polishing the gold electrode with 0.3 mu m and 0.05 mu m aluminum oxide polishing powder and rinsing with deionized water, dispersing the thionine functionalized reducing graphene oxide hydrotalcite complex in deionized ultrasound to prepare a dispersion with a concentration of 2 mg/mL, applying 0.5-50 mu L dispersion to the surface of the treated gold electrode and naturally drying at room temperature to obtain a thionine functionalized reducing graphene oxide hydrotalcite modified gold electrode, applying 1-100 mu L probe DNA with a concentration of 1 mu M to the surface of the modified electrode, and incubating at 25-70 degrees C for 2 hours, adding 10 mu L complementary DNA with different concentrations to the surface of the modified electrode at 35 degrees C and incubating for 60 minutes, and washing with phosphate buffered saline to remove unhybridized target DNA to obtain the finished product.