A highly efficient urea detection using flower-like zinc oxide nanostructures

Electrochemical immunosensor based on ZnO nanorods-Au nanoparticles nanohybrids for ovarian cancer antigen CA-125 detection

“…2. It is possible to verify well-defined peaks corresponding to the hexagonal structure of ZnO with preferred (002) orientation, according to JCPDS 36-1451 [22,36]. A typical wurtzite ZnO structure has polar nature consisting of polar and non-polar faces [37,38].…”

“…3.d) that the multi-level architecture of Au NPs over ZnO NRs would provide a higher surface area for anti-CA-125 antibody immobilization compared to other competing methods, like planar graphene sheet or gold thin film deposited on graphene [44][45]. Considering that large surface area for high enzyme loading is a key point in the fabrication of bioelectrodes [22], the ZnO NRs-Au NPs nanohybrids based electrodes have been employed for the biosensor fabrication. The calibration curve of the bare sensor is shown in Fig.4.a.…”

“…The use of Au NPs assists on immobilization of biological entities due to their interesting physicochemical properties and possibility of modifying the surface by thiolated biomolecules [13][14][15][16]. Researchers have reported that immobilization of biomolecules on AuNPs improves the stability and aids preserving the activity of biomolecules [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Besides of this, the direct electron transfer between redox species and bulk electrode materials is facilitated by using Au NPs due to their conductor nature and enhances the electrochemical sensing [14].…”

“…On the other hand, ZnO nanostructures have been utilized as matrix in biosensors due to nice biocompatibility and biomimicry, large specific area, high chemical stability and high isoelectric point (IEP~9.5) that make them favorable to immobilize and modify proteins [17][18][19][20][21]. Due to their semiconductor properties, ZnO nanostructures also provide an ideal channel for effective carrier transport during the redox process [22].…”

Application of Gold Nanoseeds in Surface- Enhanced Raman Spectroscopy for Detection of Urea

“…Most methods used to determine urea are based on indirect chemical process such as enzymatic and chemical assays [1]. Enzymatic methods use the urea-metabolizing enzyme urease, which degrades urea into ammonia.…”