Synthesis Of Metal Cobalt Nanomaterials For Biosensing And Analysis Test

The electrochemical sensor is a new science developing in recent years,and it has good applications in the life science researching.Applying the advantages of strong nanomaterial adsorption ability,good compatibility and high efficiency catalytic properties into the biosensors,made the detection sensitivity improved,the response time shortened,and realized the real-time detection of target and reduced the cost.Graphene has been widely used in electrochemical biosensor because of good conductivity,good biocompatibility and large BET surface area,which is the appropriate electrode material.Noble metal nanoparticles have good biocompatibility,strong adsorption capacity,excellent conductivity and catalytic performance.Their composite materials retain their good properties and can introduce new functionality.Noble metal nanoparticles and its composite material can be used as very good biomarkers,also good electrode materials,which have great promising application in the field of electrochemical biosensor technology.Cobalt oxide is a transition metal oxide with fascinating electronic,electrochemical,electrocatalytic,and optical properties.Co3O4-based nanocomposites have presented great potentials in various applications,such as electrochemical sensors,supercapacitors,heterogeneous catalysts,and Li-ion rechargeable batteries.As a robust two-dimensional sheet of sp2-hybridized carbon atoms,graphene has received significant attention because of its unique 2D structure with high surface area,extraordinary electronic transport properties,and unusual mechanical strength.It has been providing vast new advances in various fields,such as biological/chemical sensors,field-effect transistors,energy storage and conversion devices,ultracapacitors,etc.Many methods have been explored to fabricate graphene-based nano-composites applied for high-performance supercapacitors and biosensors.(1)Heavy metal ion is a kind of the most dangerous pollutant,and it is often accumulated in the organism for a long time without degradation.Even extremely low level of heavy metal can cause serious consequences.Therefore,the quantitative analysis of trace heavy metal ion is very important.Among many heavy metal detection methods,electrochemical analysis method is rapid,sensitive,accurate,and suitable for trace analysis with using simple and not expensive equipment.In recent years,with the development and application of nanotechnology,surface technology and synthesis of new materials development and application,electrochemical analysis will have a more broad application prospects.In this paper,we combined the nanotechnology and heavy metal electrochemical sensors together,and focused study on the application of mesoporous Co3O4 nanoparticles in the detection of Cu(?),Cd(?),As(?)and Cr(?),aiming to find a more sensitive and rapid detection method of heavy metals.Based on the electrochemical stripping voltammetry and cyclic voltammetry,we detected Cu(?),Cd(?),As(?)and Cr(?),and analyzed and discussed the experimental results.Electrochemical measurements were performed using Co304 nanobelts-modified GC electrode as working electrode,a Pt wire auxiliary electrode and a saturated calomel electrode as reference electrode.Cu(?),Cd(?)and As(?)were detected by square wave anodic stripping voltammetry,and their linear ranges were 1.0-6.0?M,0.50-5.0?M and 0.10-1.6 ?M,respectively.The experimental limits of detection(LOD)was 0.0519 ?M,0.082?M and 0.097?M,respectively.Cr(VI)was detected by cyclic voltammetry,its linear range was 1.0-6.0?M,with a limit of detection limit of 0.058 ?M.(2)Fast,sensitive and selective glucose sensing is of paramount importance because glucose detection is extremely important for the patients suffering from diabetes.There are millions of diabetics testing their blood glucose levels daily,which makes glucose the most commonly tested analyte.To solve these problems,cobalt oxide(Co3O4)was synthesized on reduced graphene oxide(rGO)in situ and the enzyme-free sensor was prepared for the quantification of glucose.The sensing parameters included wide linear range from 0.5 ?M to 92 ?M,and a remarkable lower detection limit of 25.4 nM.In addition,the rGO-Co3O4 composite was used to determine the glucose in normal people and people suffered from childhood acute lymphoblastic leukemia(ALL)and obtained satisfying result.