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Ultrasensitive immunoassay

Xiuli Fu, Lingxin Chen, Jaebum Choo
No abstract text is available yet for this article.
January 3, 2017: Analytical Chemistry
Jessica Gill, Kian Merchant-Borna, Andreas Jeromin, Whitney Livingston, Jeffrey Bazarian
OBJECTIVE: To determine whether tau changes after sport-related concussion (SRC) relate to return to play (RTP). METHODS: Collegiate athletes underwent preseason plasma sampling and cognitive testing and were followed. After a SRC (n = 46), athletes and controls (n = 37) had sampling at 6 hours, and at 24 hours, 72 hours, and 7 days after SRC. A sample of 21 nonathlete controls were compared at baseline. SRC athletes were grouped by long (>10 days, n = 23) and short (≤10 days, n = 18) RTP...
January 6, 2017: Neurology
Chang Feng, Bing Bo, Xiaoxia Mao, Hai Shi, Xiaoli Zhu, Genxi Li
Both the 3D solution and the 2D interface play important roles in bioanalysis. For the former, reactions can be carried out adequately; while for the latter, interfering substance can be eliminated simply through wash. It is a challenge to integrate the advantages of solution-based assays and the interface-based assays. Here, we report an immuno-NRCA (netlike rolling circle amplification) strategy, which integrates immunoassay with NRCA for the ultrasensitive detection of tumor biomarker, by taking the assay of a tumour marker as an example...
2017: Theranostics
Xiaoli Qin, Aigui Xu, Ling Liu, Yuyun Sui, Yunlong Li, Yueming Tan, Chao Chen, Qingji Xie
We report on an ultrasensitive metal-labeled amperometric immunoassay of proteins, which is based on the selective staining of nanocrystalline cadmium sulfide (CdS) on ZnO nanocrystals and in-situ microliter-droplet anodic stripping voltammetry (ASV) detection on the immunoelectrode. Briefly, antibody 1 (Ab1), bovine serum albumin (BSA), antigen and ZnO-multiwalled carbon nanotubes (MWCNTs) labeled antibody 2 (Ab2-ZnO-MWCNTs) were successively anchored on a β-cyclodextrin-graphene sheets (CD-GS) nanocomposite modified glassy carbon electrode (GCE), forming a sandwich-type immunoelectrode (Ab2-ZnO-MWCNTs/antigen/BSA/Ab1/CD-GS/GCE)...
December 22, 2016: Biosensors & Bioelectronics
Zhongxue Tang, Yuanyuan Fu, Zhanfang Ma
In this work, multiple signal amplification strategies for ultrasensitive label-free electrochemical immunoassay for carbohydrate antigen 24-2 (CA242) were developed using redox sodium alginate-Pb(2+)-graphene oxide (SA-Pb(2+)-GO) hydrogel. The SA-Pb(2+)-GO hydrogel was synthesised by simply mixing SA, GO, and Pb(2+) and then implemented as a novel redox species with a strong current signal at -0.46V (vs. Ag/AgCl). After the three-dimensional and porous SA-Pb(2+)-GO hydrogel was in situ generated on a glassy carbon electrode (GCE), chitosan was adsorbed on the obtained electrode to further enrich Pb(2+)...
December 22, 2016: Biosensors & Bioelectronics
Tiantian Dong, Liuyi Hu, Kang Zhao, Anping Deng, Jianguo Li
Electrochemiluminescent (ECL) immunosensor with multiple signal amplification was designed based on gold nanoparticles (AuNPs), polyamidoamine dendrimers (PAMAM) and silver-cysteine hybrid nanoribbon (SNR). Low toxic l-cysteine capped CdSe QDs was chosen as the ECL signal probe. To verify the proposed ultrasensitive ECL immunosensor for β-adrenergic agonists (β-AA), we detected Brombuterol (Brom) as a proof-of-principle analyte. Therein, AuNPs as the substrate can simplify the experiment process, accelerate the electron transfer rate, and carry more coating antigen (Ag-OVA) to enlarge ECL signal...
November 16, 2016: Analytica Chimica Acta
Sheng Xu, Rongli Zhang, Wei Zhao, Ye Zhu, Wei Wei, Xiaoya Liu, Jing Luo
In this work, a novel impedimetric immunosensor was developed based on electrophoretic deposition of polymeric self-assembled nanoparticles for the sensitive determination of carcino-embryonic antigen (CEA). Biocompatible polymeric nanoparticles γ-PGA-DA@CS were prepared by self-assembly of chitosan (CS) and dopamine modified poly(γ-glutamic acid) (γ-PGA-DA) under mild conditions. A dense and nanostructured nanoparticles film was obtained on the electrode surface by electrophoretic deposition of γ-PGA-DA@CS nanoparticles...
October 24, 2016: Biosensors & Bioelectronics
Si Cheng, Jie Sun, Junxing Yang, Jianqiang Lv, Feng Wu, Yanxing Lin, Lishan Liao, Yiyou Ye, Chenfu Cao, Liurong Fang, Qunyi Hua
A fast and ultrasensitive test-strip system combining quantum dots (QDs) with a lateral-flow immunoassay strip (LFIAS) was established for detection of Peste des petits ruminants virus (PPRV) antibody. The highly luminescent water-soluble carboxyl-functionalized QDs were used as the signal output and were conjugated to streptococcal protein G (SPG), which was capable of binding to immunoglobulin G (IgG) from many species through an amide bond to capture the target PPRV IgGs. The PPRV N protein, which was immobilized on the detection zone of the test strip, was expressed by transfecting recombinant Bacmid-PPRV-N with Lipofect into Sf9 insect cells...
January 2017: Analytical and Bioanalytical Chemistry
Zhongxue Tang, Zhanfang Ma
In this work, we presented a ratiometric electrochemical immunosensor based on redox substrate and immunoprobe. Carboxymethyl cellulose-Au-Pb(2+) (CMC-Au-Pb(2+)) and carbon-Au-Cu(2+) (C-Au-Cu(2+)) nanocomposites were firstly synthesized and implemented as redox substrate and immunoprobe with strong current signals at -0.45 V and 0.15 V, respectively. Human immunoglobulin G (IgG) was used as a model analyte to examine the analytical performance of the proposed method. The current signals of CMC-Au-Pb(2+) (Isubstrate) and C-Au-Cu(2+) (Iprobe) were monitored...
October 14, 2016: Scientific Reports
Tuhina Banerjee, Shoukath Sulthana, Tyler Shelby, Blaze Heckert, Jessica Jewell, Kalee Woody, Vida Karimnia, James McAfee, Santimukul Santra
Enterohemorrhagic Escherichia coli O157:H7 presents a serious threat to human health and sanitation and is a leading cause in many food- and waterborne ailments. While conventional bacterial detection methods such as PCR, fluorescent immunoassays and ELISA exhibit high sensitivity and specificity, they are relatively laborious and require sophisticated instruments. In addition, these methods often demand extensive sample preparation and have lengthy readout times. We propose a simpler and more sensitive diagnostic technique featuring multiparametric magneto-fluorescent nanosensors (MFnS)...
October 14, 2016: ACS Infectious Diseases
Pankaj Suman, Sonu Gandhi, Prabhanshu Kumar, Kirti Garg
Preeclampsia is a vascular multisystem disorder that accounts for varying degree of morbidity and mortality of mother and the fetus. This can be significantly averted if diagnosed at an early (18-20 weeks) stage of gestation, as there is no known way to prevent preeclampsia. In spite of extensive work on biomarker discovery, the existing method for its detection is mostly based on colorimetric immunoassays whose sensitivity is ranging in nanomolar range. Further, it has also been observed that change in the expression of a single biomarker is not sufficient to diagnose this condition...
January 2017: American Journal of Reproductive Immunology: AJRI
Nandhinee Radha Shanmugam, Sriram Muthukumar, Shalini Prasad
We demonstrate a flexible, mechanically stable, and disposable electrochemical sensor platform for monitoring cardiac troponins through the detection and quantification of cardiac Troponin-T (cTnT). We designed and fabricated nanostructured zinc oxide (ZnO) sensing electrodes on flexible porous polyimide substrates. We demonstrate ultrasensitive detection is capable at very low sample volumes due to the confinement phenomenon of target species within the ZnO nanostructures leading to enhancement of biomolecular binding on the sensor electrode surface...
2016: Scientific Reports
Dawei Fan, Xiang Ren, Haoyuan Wang, Dan Wu, Di Zhao, Yucheng Chen, Qin Wei, Bin Du
A novel and sensitive sandwich-type photoelectrochemical (PEC) sensor was fabricated using signal amplification strategy for the quantitative detection of the prostate specific antigen (PSA). CdSe nanoparticles (NPs) sensitized lanthanum-doped titanium dioxide (La-TiO2) composites were used to bind the primary antibodies (Ab1). The doping of lanthanum promoted the visible light absorption of TiO2 and remarkably enhanced the photocurrent. Moreover, 0.3%La-TiO2 displayed the highest photocurrent in the La-TiO2 composites, which was twice as much as that of undoped TiO2...
January 15, 2017: Biosensors & Bioelectronics
Lu Han, Cheng-Mei Liu, Shi-Lei Dong, Cai-Xia Du, Xiao-Yong Zhang, Lu-Hai Li, Yen Wei
Electrode materials play a vital role in the development of electrochemical immunosensors (EIs), particularly of label-free EIs. In this study, composites containing reduced graphene oxide with silver nanoparticles (rGO/Ag NPs) were synthesized using binary reductants, i.e. hydrazine hydrate and sodium citrate. Due to the fact that graphene oxide (GO) was fully restored to rGO, and rGO stacking was effectively inhibited by insertion of small Ag NPs between the graphene sheets, the electrical conductivity of rGO/Ag NPs composites was significantly improved compared to rGO alone, with an enhancement factor of 346% at 40wt% of rGO...
January 15, 2017: Biosensors & Bioelectronics
Hong Dai, Shupei Zhang, Zhensheng Hong, Yanyu Lin
It is a great challenge to fabricate multiplex and convenient photoelectrochemical biosensors for ultrasensitive determination of biomarkers. Herein, a fascinating potentiometric addressable photoelectrochemical biosensor was reported for double biomarkers' detection by varying the applied bias in the detection process. In this biosensor, the nanocomposite of cube anatase TiO2 mesocrystals and polyamidoamine dendrimers modified a dual disk electrode as an excellent photoelectrochemical sensing matrix. Subsequently, two important biomarkers in serum for prostate cancer, prostate-specific antigen and human interleukin-6, were immobilized onto the different disks of modified electrode via glutaraldehyde bridges...
October 4, 2016: Analytical Chemistry
Zhiyong Guo, Yuhong Sha, Yufang Hu, Zhongqing Yu, Yingying Tao, Yanjie Wu, Min Zeng, Sui Wang, Xing Li, Jun Zhou, Xiurong Su
A novel Faraday cage-type electrochemiluminescence (ECL) immunosensor devoted to the detection of Vibrio vulnificus (VV) was fabricated. The sensing strategy was presented by a unique Faraday cage-type immunocomplex based on immunomagnetic beads (IMBs) and multi-functionalized graphene oxide (GO) labeled with (2,2'-bipyridine)(5-aminophenanthroline)ruthenium (Ru-NH2). The multi-functionalized GO could sit on the electrode surface directly due to the large surface area, abundant functional groups, and good electronic transport property...
October 2016: Analytical and Bioanalytical Chemistry
Brunah A Otieno, Colleen E Krause, Abby L Jones, Richard B Kremer, James F Rusling
Parathyroid hormone-related peptide (PTHrP) is recognized as the major causative agent of humoral hypercalcemia of malignancy (HHM). The paraneoplastic PTHrP has also been implicated in tumor progression and metastasis of many human cancers. Conventional PTHrP detection methods like immunoradiometric assay (IRMA) lack the sensitivity required to measure target peptide levels prior to the development of hypercalcemia. In general, sensitive, multiplexed peptide measurement by immunoassay represents challenges that we address in this paper...
September 20, 2016: Analytical Chemistry
Dhiraj Acharya, Pradip Bastola, Linda Le, Amber M Paul, Estefania Fernandez, Michael S Diamond, Wujian Miao, Fengwei Bai
Zika virus (ZIKV) is a globally emerging mosquito-transmitted flavivirus that can cause severe fetal abnormalities, including microcephaly. As such, highly sensitive, specific, and cost-effective diagnostic methods are urgently needed. Here, we report a novel electrogenerated chemiluminescence (ECL)-based immunoassay for ultrasensitive and specific detection of ZIKV in human biological fluids. We loaded polystyrene beads (PSB) with a large number of ECL labels and conjugated them with anti-ZIKV monoclonal antibodies to generate anti-ZIKV-PSBs...
2016: Scientific Reports
Wooyoung Hong, Sooyeon Lee, Hee Jin Chang, Eun Sook Lee, Youngnam Cho
Circulating tumor cells (CTCs) are recognized as promising biomarkers for diagnosis and indication of the prognosis of several epithelial cancers. However, at present, CTC monitoring is available only for advanced-stage patients rather than for those at an early stage of cancer. This is because of the extraordinary rarity of CTCs and the limited sensitivity of current methods. Herein, we report the development of multifunctional magnetic nanowires for the efficient isolation and detection of CTCs from the blood of patients, especially those with non-metastatic early-stage cancer...
November 2016: Biomaterials
Jeonghyo Kim, Minji Jang, Kyoung G Lee, Kil-Soo Lee, Seok Jae Lee, Kyung-Won Ro, In Sung Kang, Byung Do Jeong, Tae Jung Park, Hwa-Jung Kim, Jaebeom Lee
Tuberculosis (TB) remains a relevant infectious disease in the 21st century, and its extermination is still far from being attained. Due to the extreme infectivity of incipient TB patients, a rapid sensing system for proficient point-of-care (POC) diagnostics is required. In our study, a plastic-chip-based magnetophoretic immunoassay (pcMPI) is introduced using magnetic and gold nanoparticles (NPs) modified with Mycobacterium tuberculosis (MTB) antibodies. This pcMPI offers an ultrasensitive limit of detection (LOD) of 1...
September 14, 2016: ACS Applied Materials & Interfaces
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