• Home
  • Search Results
  • Electrochemical cortisol immunosensors based on sonochemically synthesized zinc oxide 1D nanorods and 2D nanoflakes.

Electrochemical cortisol immunosensors based on sonochemically synthesized zinc oxide 1D nanorods and 2D nanoflakes.

Biosensors & bioelectronics (2014-07-30)
Phani Kiran Vabbina, Ajeet Kaushik, Nimesh Pokhrel, Shekhar Bhansali, Nezih Pala

We report on label free, highly sensitive and selective electrochemical immunosensors based on one-dimensional 1D ZnO nanorods (ZnO-NRs) and two-dimensional 2D ZnO nanoflakes (ZnO-NFs) which were synthesized on Au-coated substrates using simple one step sonochemical approach. Selective detection of cortisol using cyclic voltammetry (CV) is achieved by immobilizing anti-cortisol antibody (Anti-C(ab)) on the ZnO nanostructures (NSs). 1D ZnO-NRs and 2D ZnO-NFs provide unique sensing advantages over bulk materials. While 1D-NSs boast a high surface area to volume ratio, 2D-NSs with large area in polarized (0001) plane and high surface charge density could promote higher Anti-C(ab) loading and thus better sensing performance. Beside large surface area, ZnO-NSs also exhibit higher chemical stability, high catalytic activity, and biocompatibility. TEM studies showed that both ZnO-NSs are single crystalline oriented in (0001) plane. The measured sensing parameters are in the physiological range with a sensitivity of 11.86 µA/M exhibited by ZnO-NRs and 7.74 µA/M by ZnO-NFs with the lowest detection limit of 1 pM which is 100 times better than conventional enzyme-linked immunosorbant immunoassay (ELISA). ZnO-NSs based cortisol immunosensors were tested on human saliva samples and the performance were validated with conventional (ELISA) method which exhibits a remarkable correlation. The developed sensors can be integrated with microfluidic system and miniaturized potentiostat for point-of-care cortisol detection and such developed protocol can be used in personalized health monitoring/diagnostic.

Product Number
Product Description

Hexamethylenetetramine, ACS reagent, ≥99.0%
Hexamethylenetetramine, ReagentPlus®, 99%
Hexamethylenetetramine, meets analytical specification of Ph. Eur., BP, 99-100.5% (calc. to the dried substance)
Hexamethylenetetramine, puriss. p.a., reag. Ph. Eur., ≥99.5% (calc. to the dried substance)
Hydrocortisone for peak identification, European Pharmacopoeia (EP) Reference Standard
Hydrocortisone, European Pharmacopoeia (EP) Reference Standard
Hydrocortisone, γ-irradiated, powder, BioXtra, suitable for cell culture
Hydrocortisone, BioReagent, suitable for cell culture
Hydrocortisone, Pharmaceutical Secondary Standard; Certified Reference Material
Hydrocortisone, ≥98% (HPLC)
Hydrocortisone, meets USP testing specifications
Hydrocortisone, British Pharmacopoeia (BP) Assay Standard
Hydrocortisone, United States Pharmacopeia (USP) Reference Standard