Herein, wereportanovelthird-generationH2O2 and IO3  biosensor,whichwasfabricatedbyloading
catalase (CAT)onto L-lysine/multiwalledcarbonnanotube(PLL/f-MWCNT) film modified glassycarbon
electrode (GCE).TheUV–visible (UV–vis) andFourier-transforminfrared(FTIR)spectrashowthatthe
catalase encapsulatedinthePLL/f-MWCNT film caneffectivelyretainitsbioactivity.Theimmobilized
CATretaineditsbioactivitywithahighproteinloadingof4.0721010 mol cm2, thusexhibitinga
surface-controlled reversibleredoxreaction,withafastheterogeneouselectrontransferrateof5.48s1.
The immobilizedCATshowsacoupleofreversibleandwell-defined cyclicvoltammetrypeakswitha
formal potential(E0) of 0.471V(vs.Ag/AgCl)inapH6.5phosphatebuffersolution(PBS).Moreover,the
modified film exhibitedhighelectrocatalyticactivityforthereductionofhydrogenperoxide(H2O2).
It exhibitedawidelinearresponsetoH2O2 in theconcentrationrangeof1106–3.6103, with
higher sensitivity(392mAcm2 M1) andalowerMichaelis–Menten constant(0.224mM).Itprovided
high-catalytic activitytowardsH2O2 in ashortertime(5s),withadetectionlimitof8nM.Theseresults
indicate greatimprovementintheelectrochemicalandelectrocatalyticpropertiesoftheCAT/PLL/
f-MWCNTbiosensor,offeringanewideaforthedesignofthird-generationelectrochemicalbiosensors.