Novel CeO2–CuO-decorated enzymatic lactate biosensors operating in low oxygen environments

Abstract

The detection of the lactate level in blood plays a key role in diagnosis of some pathological conditions including cardiogenic or endotoxic shocks, respiratory failure, liver disease, systemic disorders, renal failure, and tissue hypoxia. Here, we described for the first time the use of a novel mixed metal oxide solution system to address the oxygen dependence challenge of first generation amperometric lactate biosensors. The biosensors were constructed using ceria-copper oxide (CeO2-CuO) mixed metal oxide nanoparticles for lactate oxidase immobilization and as electrode material. The oxygen storage capacity (OSC, 492 μmol-O2/g) of these metal oxides has the potential to reduce the oxygen dependency, and thus eliminate false results originated from the fluctuations in the oxygen concentration. In an effort to compare the performance of our novel sensor design, ceria nanoparticle decorated lactate sensors were also constructed. The enzymatic activity of the sensors were tested in oxygen-rich and oxygen-lean solutions. Our results showed that the OSC of the electrode material has a big influence on the activity of the biosensors in oxygen-lean environments. While the CeO2 containing biosensor showed an almost 21% decrease in the sensitivity in a O2-depleted solution, the CeO2-CuO containing electrode, with a higher OSC value, experienced no drop in sensitivity when moving from oxygen-rich to oxygen-lean conditions. The CeO2-CuO decorated sensor showed a high sensitivity (89.3 ± 4 μA mM(-1) cm(-2)), a wide linear range up to 0.6 mM, and a low limit of detection of 3.3 μM. The analytical response of the CeO2-CuO decorated sensors was studied by detecting lactate in human serum with good selectivity and reliability. The results revealed that CeO2-CuO containing sensors are promising candidates for continuous lactate detection.

The Use of CeO2-TiO2 Nanocomposites as Enzyme Immobilization Platforms in Electrochemical Sensors

“…oxidation current graph is shown in Figure 4a. It was found that the oxidation current of Pt/CeO2-TiO2/LOx/Nf sensors measured at 0.8 V increased linearly with the increasing scan rate as shown in Figure 4b, demonstrating that the oxidation of H2O2 on the surface of the sensor is a surface controlled electrochemical reaction (9).…”

“…The results showed that the chemical modification of CeO2 nanostructures enhanced the electrochemical performance significantly. In our previous works, we demonstrated that the modification of CeO2 lattice with a second metal oxide system altered the physicochemical properties of the nanoparticles, which in turn resulted in an enhanced catalytic performance (9,10,24).…”

Synthesis of Mixed Cu/Ce Oxide Nanoparticles by the Oil-in-Water Microemulsion Reaction Method

“…Recently, it has been shown that CeO 2 -CuO mixed oxide nanomaterials were promising nanocatalysts for the preferential oxidation of CO [14]. Copper oxide nanomaterials are applied in various areas: gas sensors [15], biosensors [16], batteries [17], high temperature superconductors [18], solar energy conversion [19], field emission emitters [20], and catalysis [21]. It has been reported that the efficiency of CeO 2 -CuO nanocatalysts could be related to synergetic interactions between CeO 2 and CuO promoting special redox properties at their interface [22].…”

Sılar Yöntemi ile Üretilen CuO Filmlerin Yapısal, Morfolojik ve Optik Özelliklerine İkili Katkılamanın (Zn, Li) Etkisi

“…CuO monoklinik kristal yapıya sahip, zehirli olmayan, ucuz, kolay sentezlenebilen ve doğada bol bulunan bir yarıiletken malzemedir. Bu yüzden CuO ince filmler biyosensörler [5], gaz sensörleri [6], güneş pilleri [7], lityum iyon bataryalar [8], ince film transistörler [9] gibi teknolojinin birçok alanında değişik uygulamalar için yaygın biçimde araştırılmaktadır.…”