title: Novel electrochemical immunoassay for quantitative monitoring of biotoxin using target-responsive cargo release from mesoporous silica nanocontainers.
abstract: A novel homogeneous immunoassay protocol was designed for quantitative monitoring of small molecular biotoxin (brevetoxin B, PbTx-2, as a model) by using target-responsive cargo release from polystyrene microsphere-gated mesoporous silica nanocontainer (MSN). Initially, monoclonal mouse anti-PbTx-2 capture antibody was covalently conjugated onto the surface of MSN (mAb-MSN), and the electroactive cargo (methylene blue, MB) was then trapped in the pores of mAb-MSN by using aminated polystyrene microspheres (APSM) based on the electrostatic interaction. Upon addition of target PbTx-2, the positively charged APSM was displaced from the negatively charged mAb-MSN because of the specific antigen-antibody reaction. Thereafter, the molecular gate was opened, and the trapped methylene blue was released from the pores. The released methylene blue could be monitored by using a square wave voltammetry (SWV) in a homemade microelectrochemical detection cell. Under optimal conditions, the SWV peak current increased with the increasing of PbTx-2 concentration in the range from 0.01 to 3.5 ng mL(-1) with a detection limit (LOD) of 6 pg mL(-1) PbTx-2 at the 3Sblank criterion. Intra- and interassay coefficients of variation with identical batches were ≤6% and 9.5%, respectively. The specificity and sample matrix interfering effects were acceptable. The analysis in 12 spiked seafood samples showed good accordance between results obtained by the developed immunoassay and a commercialized enzyme-linked immunosorbent assay (ELISA) method. Importantly, the target-responsive controlled release system-based electrochemical immunoassay (CRECIA) offers a promising scheme for the development of advanced homogeneous immunoassay without the sample separation and washing procedure.
authors.affiliation: Key Laboratory of Analysis and Detection for Food Safety (Ministry of Education & Fujian Province), Department of Chemistry, Fuzhou University , Fuzhou 350108, People's Republic of China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.forename: Bingqian
authors.initials: B
authors.lastname: Liu
authors.forename: Jiayao
authors.initials: J
authors.lastname: Liao
authors.forename: Guonan
authors.initials: G
authors.lastname: Chen
authors.forename: Dianping
authors.initials: D
authors.lastname: Tang
mesh_terms: D055664:Electrochemical Techniques; D004566:Electrodes; D007118:Immunoassay / Q000379:methods*; D008387:Marine Toxins / Q000032:analysis*; D053758:Nanoparticles / Q000737:chemistry*; D035964:Oxocins / Q000032:analysis*; D010316:Particle Size; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D000095702:Polyether Toxins
chemical_list: D008387:Marine Toxins; D035964:Oxocins; D012822:Silicon Dioxide; C051732:Ptychodiscus brevis T2 toxin; C043466:brevetoxin B; D000095702:Polyether Toxins