Helical Carbon Nanotubes: Intrinsic Peroxidase Catalytic Activity and Its Application for Biocatalysis and Biosensing

Abstract

A combined hydrothermal/hydrogen reduction method has been developed for the mass production of helical carbon nanotubes (HCNTs) by the pyrolysis of acetylene at 475 °C in the presence of Fe(3)O(4) nanoparticles. The synthesized HCNTs have been characterized by high-resolution transmission electron microscopy, scanning electron microscopy, X-ray diffraction analysis, vibrating sample magnetometry, and contact-angle measurements. The as-prepared helical-structured carbon nanotubes have a large specific surface area and high peroxidase-like activity. Catalysis was found to follow Michaelis-Menten kinetics and the HCNTs showed strong affinity for both H(2)O(2) and 3,3',5,5',-tetramethylbenzidine (TMB). Based on the high activity, the HCNTs were firstly used to develop a biocatalyst and amperometric sensor. At pH 7.0, the constructed amperometric sensor showed a linear range for the detection of H(2)O(2) from 0.5 to 115 μM with a correlation coefficient of 0.999 without the need for an electron-transfer mediator. Because of their low cost and high stability, these novel metallic HCNTs represent a promising candidate as mimetic enzymes and may find a wide range of new applications, such as in biocatalysis, immunoassay, and environmental monitoring.

Novel synthesis of NiS/MMT/GO nanocomposites with enhanced peroxidase-like activity for sensitive colorimetric detection of glutathione in solution

“…Thus, the ESR results were consistent with that obtained by fluorescent probe. In a word, according to the experimental results together with the relevant studies [47,48], the efficient catalytic performance of NiS/MMT/GO nanocomposites may originate from the electron transfer among catalysts, TMB and H 2 O 2 . It was thought that TMB molecules were absorbed on the surface of NiS/MMT/GO and donated lone-pair electrons from the amino groups to nanocomposites, leading to higher electron density and mobility of NiS/MMT/GO nanocomposites.…”

Incorporating ATP into biomimetic catalysts for realizing exceptional enzymatic performance over a broad temperature range

“…Owing to the excellent catalytic properties of these nanomaterials, Scrimin and co-workers 7 called them 'nanozymes' in analogy to the nomenclature of catalytically active polymers (synzymes). Magnetic nanoparticles, 4,9 CeO 2 , 6,10-12 V 2 O 5 , 13,14 gold nanoparticles, 7,8,[15][16][17][18] PtPd ÀFe 3 O 4 , 19,20 carbon nanotubes, 21,22 graphene oxide and graphene nanocomposites 23,24 and other types of nanoparticle have been found to exhibit unique enzyme-like catalytic activities and have already shown promising applications in medicine, biotechnology and environmental chemistry.…”

“…4,13,[19][20][21][22][23][24] Nevertheless, the binding affinity and substrate specificity of most nanomaterial-based peroxidase mimics remain lower than those of natural enzymes (Supplementary Scheme S1). 25 The reason for such differences is that in the active site of natural enzymes, a pocket is available for substrate recognition and catalysis.…”

“…They possess relatively low catalytic activity; additionally, despite superior thermal stability, their catalytic performance as a function of temperature (especially at high temperature) was far below expectations. Given the outstanding versatility of nanozyme-based applications, 4,13,[19][20][21][22][23][24] there is a great need to develop peroxidase mimics that are able to exhibit high catalytic activity over a broad temperature range, particularly at high temperatures. With this goal in mind, we sought effective promoters to enhance this enzyme-like activity.…”

Intrinsic Catalytic Activity of Gold/Multi-Walled Carbon Nanotubes Composites in Squaric Acid-Iron(II/III) System

“…Among these materials, CNTs have been extensively employed for synthesis of hybrid materials in sensing and catalysis due to their electrical conductivity, high chemical stability, unusual conjugated structure, and significant mechanical strength [5][6][7]. Cui et al developed helical CNTs by employing the hydrothermal/hydrogen reduction method, involving a large specific surface area and high catalytic activity [8]. As the catalyst support, extensive efforts have been made in the past several decades.…”