Abstract
Hydrogen peroxide (H2O2) is a partially reduced metabolite of oxygen that exerts a diverse array of physiological and pathological activities in living organisms. Therefore, the accurate quantitative determination of H2O2 is crucial in clinical diagnostics, the food industry, and environmental monitoring. Herein we report the electrosynthesis of silver nanoflowers (AgNFs) on indium tin oxide (ITO) electrodes for direct electron transfer of hemoglobin (Hb) toward the selective quantification of H2O2. After well-ordered and fully-grown AgNFs were created on an ITO substrate by electrodeposition, their morphological and optical properties were analyzed with scanning electron microscopy and UV–Vis spectroscopy. Hb was immobilized on 3-mercaptopropionic acid-coated AgNFs through carbodiimide cross-linking to form an Hb/AgNF/ITO biosensor. Electrochemical measurement and analysis demonstrated that Hb retained its direct electron transfer and electrocatalytic properties and acted as a H2O2 sensor with a detection limit of 0.12 µM and a linear detection range of 0.2 to 3.4 mM in phosphate-buffered saline (PBS). The sensitivity, detection limit, and detection range of the Hb/AgNF/ITO biosensor toward detection H2O2 in human serum was also found to be 0.730 mA mM−1 cm−2, 90 µM, and 0.2 to 2.6 mM, indicating the clinical application for the H2O2 detection of the Hb/AgNF/ITO biosensor. Moreover, interference experiments revealed that the Hb/AgNF/ITO sensor displayed excellent selectivity for H2O2.
Highlights
Hydrogen peroxide (H2O2) is a reactive oxygen by-product that acts as a key regulator of various oxidative stress-related processes [1,2]
Triton X-100 was purchased from GeorgiaChem (Smyrna, GA, USA), whereas H2O2 was obtained from OCI Ltd. (Seoul, Korea) and diluted in deionized water for preparation of the desired molar concentrations
The AgNF/indium tin oxide (ITO) electrodes were incubated with 50 mM of 3-mercaptopropionic acid (3-MPA) for 3 h to allow the formation of a self-assembled monolayer (SAM) from –COOH groups
Summary
Hydrogen peroxide (H2O2) is a reactive oxygen by-product that acts as a key regulator of various oxidative stress-related processes [1,2]. The utilization of nanoparticles (such as Au, Ag, Cu, and Fe) for the creation of nanostructures has received much attention because of their unique morphology, grain size, and physical, electrical, and magnetic properties that make them suitable for application in the fields of drug delivery [12], optoelectronics [13], energy storage elements [14], and microfluidics [15]. Many efforts have been made to synthesize materials characterized by structural, compositional, and morphological uniformity, with a high sbuyrfsatcruecttourvalo,lcuommeporasittiioonaalllo, awnidnmg othrpeihroalopgpicliaclautinoinforinmivtya,rwioiuths aehmigehrgsiunrgfafcieeltdosvo[1lu6m]. HHeemmoogglolobbinin((HHbb))isis aa FFee((IIII))--pprroottooppoorrpphhyyrrinin IIXX ((hheemmee))--ccoonnttaaininininggpprrootteeinintthhaatt ccoonnttaaininss tthhee ““gglloobbiinn ffoolldd”” ddoommaaiinn aanndd rreevveerrssiibbllyy bbiinnddss mmoolleeccuullaarrooxxyyggeenn..IItthhaassaammoolalarrmmaassssooffaapppprrooxxiimmaatteelyly 6677,0,00000gg/m/mool lanadndisicsocmopmopseodseodf otwf otwao- aan-datnwdotbw-soubbu-snuibtsu, neiatcsh, ecaocnhtacinoinntgaionninegmoonleecumleoloefcuhelemoef [h22e]m. He [b22is].fHoubnids fionuhnudminanhuermytahnroercyytthesro(cryedtesbl(oreodd bcleollosd) actelalsc)oant caecnotrnacteionntraotfioanpporfoaxpimpraotxeilmy a3t0e%ly (3w0/%v)(wor/v2)0omr 2M0 m(inMh(einmhee).mAem). TThhee ssuurrffaaccee mmoorrpphhoolologgyyaannddtthhee ooppttiiccaall cchhaarraacctteerrisistticicssoofftthhee AAggNNFFsswweerreeeexxaammiinneeddwwitihthssccaannnnininggeelelecctrtroonnmmicicrorossccooppyyaannddUUVV––VVisisssppeecctrtroossccooppyy,,wwhhiilleetthheeddirireecctt eelleeccttrroonnttrraannssffeerr bbyy HHbb iimmmmoobbiilliizzeeddoonnAAggNNFFeelelecctrtoroddeseswwasasinivnevsetsigtiagtaetdedeleecletrcotrcohcehmeimcaicllayl.lyB.aBseadseodn oonuorurresruelstusl,tws, ewperporpoopsoestehtehde edveevleolpompmenetnot fofaasesnensistiitviveeeelelecctrtorocchheemmicicaallHH22OO22 sseennssoorr bbaasseeddoonnHHbb aaddssoorrbbeeddoonnAAggNNFF-m-mooddifiifieeddITITOOeelelecctrtrooddeess((HHbb/A/AggNNFF/I/ITTOO)). .FFigiguurree11sshhoowwssaa sscchheemmaattiiccddiiaaggrraamm ssuummmmaarrizizininggththeemmeeththooddoolologgyywweeeemmpploloyyeeddfoforrccrreeaatitninggoouurrpprrooppoosseeddmmooddifiifieeddeeleleccttrrooddeeaannddiittss aapppplliiccaattiioonnttoowwaarrddHH22OO22ddeteetcetcitoionn
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