A Novel Fluorescent Biosensor For Adenosine Triphosphate Detection Based On A Metal-Organic Framework Coating Polydopamine Layer

A novel and sensitive fluorescent biosensor based on polydopamine coated Zr-based metal-organic framework(PDA/UiO-66)is presented for adenosine triphosphate(ATP)detection.This PDA/UiO-66 nanoparticle which holds a great potential to be excellent fluorescence quencher can protect the 6-carboxyfluorescein(FAM)-labeled probe from cleaved by DNase I dispersed in solution and the flurescence of labeled FAM is quenched.When ATP molecules exist,aptamers on the PDA/UiO-66 nanoparticles can hybridize with ATP molecule to form complex structure that will be desorbed from the PDA/UiO-66 and digested by DNase I.After that,the released ATP molecule can react with another aptamer on the PDA/UiO-66 complexes,then restarts a new cycle.Herein,the excellent strong fluorescence quenching ability and uploading more amount of aptamer probes of PDA/UiO-66 composites make them efficient biosensors,leading to a high sensitivity with detection limit of 35 nM.Compared with ATP detection directly by UiO-66-based method,the LOD is about 5.7 times lower with PDA/UiO-66 nanoparticle.Moreover,the enhanced biocompatibility and bioactivity with PDA layer of the composites render a proposed strategy for clinical diagnosis field of detecting small biological molecules in vivo in the future.Besides,this paper also presents a disposable electrochemical immunosensor for facile and rapid detection of interferon gamma(IFN-γ)based on patterned gold electrodes encoding specific aptamer with unique redox reporter.Standard photolithography and metal etching techniques are used to fabricate gold electrode arrays.Formation of super-hydrophobic patterning affinity to blank area of substrate is to support testing sample without any extra tanks.Aptamers self-assembled onto the electrodes straightly is used to detect cytokines.Compared with electrodes integrated into microfluidic devices published before which used to monitor cytokines,electrodes we designed are better of convenience,high efficiency and also conformed to the development trend of modern detection.Furthermore,this kind of successful point-of-care test(POCT)experiments may also be carried out to detect the real human serum as expectation in the future.