Self-powered Immunoglobulin G Biosensor By The Coupling Of Piezoelectric Effect And Surface Effect

In recently years,biosensors have great application in food industry,chemical pharmaceutical,environmental monitoring,medical diagnostics and biological chips.With the development of biological science and materials science,the biosensors with miniaturization,high sensitivity,high stability and high life are desired.Although biosensors have been intensively investigated,the supplied power of sensors is still a problem.Traditional biosensors require an external power to provide the energy for the normal working.However,biosensors using the battery cannot meet the requirements as the limitation of miniaturization and high life.In order to solve the problem,in this paper,we integrate nanogenerators and biosensors in a single device to achieve self-powered biosensor.Specific studies are as follows:(1)Self-powered biosensor has been realized from ZnO nanowire(NW)nanogenerator(NG).The piezoelectric output generated by ZnO N W NG can act not only as a power source for driving the device,but also as a biosensing signal.The adsorption of bio molecules on the surface of ZnO NWs can modify the free-carrier density,which vary the screen effect of free-carriers on the piezoelectric output.After immersing in 10-3 g ml-1 human immunoglobulin G(IgG),the piezoelectric output voltage of the device decreases from 0.203 ± 0.0176 V(without IgG)to 0.038±0.0035 V under compressive deformation.Such a self-powered biosensor has higher response than transistor-type biosensor(I-V behavior).The response of self-powered biosensor is in a linear relationship with IgG concentration(logarithm,10-7-10-3 g ml-1)and the limit of detection(LOD)on IgG of the device is about 6.9 ng ml-1.(2)Highly stable piezo-immunoglobulin-biosensing has been realized from SiO2/ZnO nanowire(NW)nanogenerator(NG)as self-powered biosensor.The IgG biomolecules modified on the surface of SiO2/ZnO NW acts as a gate potential,and the field effect can influence the surface electron density of ZnO NWs,which varies the screening effect of free-carriers on the piezoelectric output.The stability of the device is very high,and the relative standard deviation(RSD)ranges from 1.20%to 4.20%.The limit of detection(LOD)on IgG of the device can reach 5.7 ng/mL.The response of the device is in a linear relationship with IgG concentration.The biosensing performance of SiO2/ZnO NWs is much higher than that ofbare ZnO NWs.SiO2 layer uniformly coated on the surface of ZnO NW acts as the gate insulation layer,which increases mechanical robustness and protects it from the electrical leakages and short circuits.