scholarly journals A Sensitive Capacitive Biosensor for Protein a Detection Using Human IgG Immobilized on an Electrode Using Layer-by-Layer Applied Gold Nanoparticles

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 99
Author(s):  
Kosin Teeparuksapun ◽  
Martin Hedström ◽  
Bo Mattiasson

A capacitive biosensor for the detection of protein A was developed. Gold electrodes were fabricated by thermal evaporation and patterned by photoresist photolithography. A layer-by-layer (LbL) assembly of thiourea (TU) and HAuCl4 and chemical reduction was utilized to prepare a probe with a different number of layers of TU and gold nanoparticles (AuNPs). The LbL-modified electrodes were used for the immobilization of human IgG. The binding interaction between human IgG and protein A was detected as a decrease in capacitance signal, and that change was used to investigate the correlation between the height of the LbL probe and the sensitivity of the capacitive measurement. The results showed that the initial increase in length of the LbL probe can enhance the amount of immobilized human IgG, leading to a more sensitive assay. However, with thicker LbL layers, a reduction of the sensitivity of the measurement was registered. The performance of the developed system under optimum set-up showed a linearity in response from 1 × 10−16 to 1 × 10−13 M, with the limit detection of 9.1 × 10−17 M, which could be interesting for the detection of trace amounts of protein A from affinity isolation of therapeutic monoclonal antibodies.

2011 ◽  
Vol 298 ◽  
pp. 128-134
Author(s):  
Ai Chun Zhang ◽  
Cun Zhou

In this paper, a novel DNA electrochemical biosensor based on layer-by-layer self-assembled technology was reported. Gold nanoparticles were firstly immobilized on chitosan modified gold electrode by large amino of chitosan because of strong electrostatic adsorption effect between amino and gold atom, and thoil group modified DNA (SH-ssDNA) probe sequence was then self-assembled onto the electrode. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were applied to investigate the electrochemical behavior of different modified electrodes with methylene blue as hybrid indicator. The results in optimization experiment condition show that: The peak current difference value pre and post hybridization was linearly related to the logatithmic value of the target DNA concentration ranging from 10-8~10-5mol/L.A detection limit of 3.55×10-9mol/L can be estimated.


2016 ◽  
Vol 363 ◽  
pp. 566-571 ◽  
Author(s):  
Lijun Sun ◽  
Xiaojun Liu ◽  
Qiaoling Sun ◽  
Meng Cai ◽  
Jiajing Zhou ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rozita Abolhasan ◽  
Balal Khalilzadeh ◽  
Hadi Yousefi ◽  
Sahar Samemaleki ◽  
Forough Chakari-Khiavi ◽  
...  

AbstractIn the present article, we developed a highly sensitive label-free electrochemical immunosensor based on NiFe-layered double hydroxides (LDH)/reduced graphene oxide (rGO)/gold nanoparticles modified glassy carbon electrode for the determination of receptor tyrosine kinase-like orphan receptor (ROR)-1. In this electrochemical immunoassay platform, NiFe-LDH/rGO was used due to great electron mobility, high specific surface area and flexible structures, while Au nanoparticles were prepared and coated on the modified electrodes to improve the detection sensitivity and ROR1 antibody immobilizing (ROR1Ab). The modification procedure was approved by using cyclic voltammetry and differential pulse voltammetry based on the response of peak current to the step by step modifications. Under optimum conditions, the experimental results showed that the immunosensor revealed a sensitive response to ROR1 in the range of 0.01–1 pg mL−1, and with a lower limit of quantification of 10 attogram/mL (10 ag mL−1). Furthermore, the designed immunosensor was applied for the analysis of ROR1 in several serum samples of chronic lymphocytic leukemia suffering patients with acceptable results, and it also exhibited good selectivity, reproducibility and stability.


Pharmaceutics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 261
Author(s):  
Wei Mao ◽  
Sol Lee ◽  
Ji Un Shin ◽  
Hyuk Sang Yoo

Surface initiated atom transfer radical polymerization (SI-ATRP) documented a simple but efficient technique to grow a dense polymer layer on any surface. Gold nanoparticles (AuNPs) give a broad surface to immobilize sulfhyryl group-containing initiators for SI-ATRP; in addition, AuNPs are the major nanoparticulate carriers for delivery of anti-cancer therapeutics, since they are biocompatible and bioinert. In this work, AuNPs with a disulfide initiator were polymerized with sulfoethyl methacrylate by SI-ATRP to decorate the particles with anionic corona, and branched polyethyeleneimine (PEI) and siRNA were sequentially layered onto the anionic corona of AuNP by electrostatic interaction. The in vitro anti-cancer effect confirmed that AuNP with anionic corona showed higher degrees of apoptosis as well as suppression of the oncogene expression in a siRNA dose-dependent manner. The in vivo study of tumor-bearing nude mice revealed that mice treated with c-Myc siRNA-incorporated AuNPs showed dramatically decreased tumor size in comparison to those with free siRNA for 4 weeks. Furthermore, histological examination and gene expression study revealed that the decorated AuNP significantly suppressed c-Myc expression. Thus, we envision that the layer-by-layer assembly on the anionic brushes can be potentially used to incorporate nucleic acids onto metallic particles with high transfection efficiency.


2012 ◽  
Vol 52 (5) ◽  
pp. 1043-1051 ◽  
Author(s):  
Panittamat Kumlangdudsana ◽  
Adisorn Tuantranont ◽  
Stephan Thierry Dubas ◽  
Luxsana Dubas

RSC Advances ◽  
2015 ◽  
Vol 5 (70) ◽  
pp. 56583-56589 ◽  
Author(s):  
Yulan Wang ◽  
Dan Wu ◽  
Yong Zhang ◽  
Xiang Ren ◽  
Yaoguang Wang ◽  
...  

In this work, a novel and ultrasensitive label-free electrochemical immunosensor was developed for the quantitative detection of alpha fetoprotein (AFP).


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