Application Of Conjugated Polymer And Metallic Nanocrystals For Electrochemical Sensors

Detection of specific material plays a key role in industry,agriculture,life science and environmental protection.Therefore,the development of electrochemical sensors with high sensitivity,high specificity,fast response and low cost has attracted extensive attention.Functional electrode materials can effectively improve the electrochemical signal of the sensor,and the study of modified electrode materials with good performance is an important topic in the field of electrochemical sensors.At present,various materials with excellent performance such as carbon nanomaterials,conductive polymers,transition metals,metals,metal oxides and bioactive molecules have improved the analytical performance of electrochemical biosensors.Electrode materials with special functions are designed and synthesized from multiple dimensions to enable them to detect various biomolecules with specific sensitivity,which provide wider application potential for biosensing construction and medical diagnostics.Conducting polymers have attracted our attention due to their excellent conductivity and redox properties.At the same time,the conjugated conductive polymers with Donor-Acceptor structure are proved to be more favorable for electron migration.The bimetallic nanocatalysts as the promising candidates extend the functions of nanocarriers,displaying excellent catalytic ability,conductivity,biocompatibility and long-term stability.Therefore,this paper aims to fabricate electrochemical sensors with conjugated polymers and metallic nanocrystals for the detection of small biological molecules and Human IgG.1.Phenothiazine,a conjugated nitrogen-sulfur heterocyclic compound with broad pharmaceutical profile,is a strong electron donating system and applied in the synthesis of various classic antipsychotic drugs.Diphenylfumaronitrile unit displays distinct advantages as acceptor building block for constructing charge-transfer materials with its two cyano functionalities,it can provide an extendedπ-conjugated system.Inthisproposal,anovelDonor–Acceptormolecule,2,3-bis（4-（10Hphenothiazin-10-yl）phenyl）fumaronitrile（PTBFN）,containig a diphenylfumaronitrile as the electrophilic central core and two phenothiazines as the peripheral electron donor functional groups is first designed and synthesized.Subsequently,the charge-transfer layer based on the PTBFN polymer,poly（PTBFN）,is obtained via a straightforward electrochemical method and used as an efficient electrocatalyst for dopamine detection.The favorable sensing performance suggests that the nontrivial Donor–Acceptor architecture is one of the promising bioaffinity catalysts for electrocatalysis and expected to provide wider application potential for biosensing construction and medical diagnostics.2.The combination of nanoparticles and biomarkers yields functional nanostructured biointerface,which plays a notable role in biotechnology development.Au-Pt star-shaped decahedra not only acts as efficient scaffold for immobilization of antibody,but also exhibits superior electrocatalytic activity toward H₂O₂ reduction.The nanocrystal as the efficient signal transduction label is first employed to construct an electrochemical immunosensor.Donor–π–Acceptor linking is considered as a suitableπ-conjugated backbone for conducting polymer on biointerface application.A Donor–π–Acceptor architecture which imidazole as theπ-bridge and amino phenyl/phenyl groups as peripheral electron–donating/withdrawing functional groups,4-（2,4,5-triphenyl-1H-imidazol-1-yl）aniline（TPIDA）is designed and synthesized for good biocompatibility and high conductivity.In this proposal,we attempt to integrate the above mentioned two features from nanobiotechnology and organic bioelectronics.Then,a novel nonenzymatic sandwich-type immunosensor is performed by Au-Pt core-shell with surface-engineered twinning as a label andπ-conjugated Donor–π–Acceptor polymers as the signal amplification platform.Human IgG（HIgG）as the model target protein can be detected with a wide linear range from 0.1 pg mL^-1 to 100 ng mL^-1.Moreover,as a practical application,the prepared biosensor is used to monitor HIgG level in human serum with desirable results obtained.