Nanoceria based electrochemical sensor for hydrogen peroxide detection

Abstract

Oxidative stress is a condition when the concentration of free radicals and reactive molecular species rise above certain level in living systems. This condition not only perturbs the normal physiology of the system but also has been implicated in many diseases in humans and other animals. Hydrogen peroxide (H2O2) is known to be involved in induction of oxidative stress and has also been linked to a variety of ailments such as inflammation, rheumatoid arthritis, diabetes, and cancer in humans. It is one of the more stable reactive molecular species present in living systems. Because of its stability and links with various diseases, sensing the level of H2O2 can be of great help in diagnosing these diseases, thereby easing disease management and amelioration. Nanoceria is a potent candidate in free radical scavenging as well as sensing because of its unique redox properties. These properties have been exploited, in the reported work, to sense and quantify peroxide levels. Nanoceria has been synthesized using different capping agents: Hexamethylene-tetra-amine (HMTA) and fructose. CeO2-HMTA show rhombohedral and cubic 6.4 nm particles whereas CeO2-fructose are found to be spherical with average particle diameter size 5.8 nm. CeO2-HMTA, due to the better exposure of the active (200) and (220) planes relative to (111) plane, exhibits superior electrocatalytic activity toward H2O2 reduction. Amperometric responses were measured by increasing H2O2 concentration. The authors observed a sensitivity of 21.13 and 9.6 μA cm(-2) mM(-1) for CeO2-HMTA and CeO2-fructose, respectively. The response time of 4.8 and 6.5 s was observed for CeO2-HMTA and CeO2-fructose, respectively. The limit of detection is as low as 0.6 and 2.0 μM at S/N ratio 3 for CeO2-HMTA and CeO2-fructose, respectively. Ceria-HMTA was further tested for its antioxidant activity in an animal cell line in vitro and the results confirmed its activity.

Facile preparation of graphene nanoribbon/cobalt coordination polymer nanohybrid for non-enzymatic H2O2 sensing by dual transduction: electrochemical and fluorescence

“…Hz in the impedance data as discussed in our previous reports [39,58]. D a across the MCPs@GNR/electrolyte interface is found to be 3.3×10 -7 cm 2 s -1 which is observed to be apparently 1.5 times higher than 2.08×10 -7 cm 2 s -1 for GNR electrode and ~14 times higher than 2.4×10 -8 cm 2 s -1 for MCPs electrode (Figure 7b).…”

“…Consequently, ion diffusibility in vertical as well as horizontal direction is enhanced [59]. Peak currents, I pa and I pc are linearly proportional to the scan rate (Inset Figure 7e) with I pa /I pc ratio about unity in the range from 5 to 200 mVs -1 (I pa R 2 =0.9963; I pc R 2 =0.9976) reflecting surface-controlled reversible process [58]. It is observed that both anodic peak (E pa ) and cathodic peak (E pc ) shift slightly to the positive and negative direction respectively.…”

Adsorption of Nanoceria by Phosphocholine Liposomes

“…1 Its unique properties are attributed to the surface Ce 3+ ions, providing a redox couple with Ce 4+ . 2,3 The Ce 3+ sites are accompanied by oxygen vacancies near the surface. Therefore, small CeO2 NPs of several nanometers possess enhanced activities due to a large surface-to-volume ratio.…”

Printable multi-walled carbon nanotubes thin film for high performance all solid state flexible supercapacitors

“…Apparent diffusion coefficient (Da) of electrolyte ions is estimated from the diffusion controlled regime (ΔZim/ΔZre ≈ 1) which lies in the frequency range ~ 8 Hz -0.8 Hz of the impedance data. Da across the electrode/electrolyte interface is calculated from the slope of plot |Z| vs ω -1/2 as previous reports [28,29] and is found to be 2.25x10 -8 cm 2 /s (Fig. 3d).…”