Ultrasensitive electrochemical immunosensor for quantitative detection of HBeAg using Au@Pd/MoS2@MWCNTs nanocomposite as enzyme-mimetic labels
Introduction
As one of the most severe public health problems, the hepatitis B virus (HBV) infection can trigger cirrhosis and hepatocellular carcinoma (HCC), the third leading fearful cause of cancer death (Ledesma et al., 2011, da Costa Ferreira et al., 2017). Hepatitis B e antigen (HBeAg) has been identified as the reliable tumor marker for diagnosis and prognosis of disease caused by HBV infection (Magnius and Espmark, 1972, Ott et al., 2012). The HBeAg could increase immune tolerance during neonatal transmission and hinder immune response against the related core protein (Milich and Liang, 2003, Milich et al., 1990). The previous research has shown that relative risks for developing HCC of HBeAg positivity was about 50% higher than HBeAg negativity (Ganem and Prince, 2004). Thus, accurate detection of HBeAg is significantly crucial to the HCC diagnosis.
With the rapid development of technology, many methods have been applied to the biomarker detection. However, there were few research methods for HBeAg detection. Recently, the sandwich-type electrochemical immunosensor has attracted burgeoning attention, due to its unique advantages of rapid response, good sensitivity, convenient operation and excellent specificity (Teymourian et al., 2013). As a diagnostic tool, it is a great promising approach to detect HBeAg.
For sandwich-type electrochemical immunosensors, a crucial strategy of detection is to achieve signal amplification by coupling different labels of secondary antibody (Ab2) (Li et al., 2017a). In this work, gold@palladium nanoparticles loaded by molybdenum disulfide functionalized multiwalled carbon nanotubes (Au@Pd/MoS2@MWCNTs) were proposed to label secondary antibodies (Ab2), improving the sensitivity of immunosensor. Due to excellent stability, superior catalytic efficiency and ease of mass production, enzyme mimics such as metal complexes, polymers and supramolecules have drawn widespread attention in bionanotechnology, such as biosensing, bioimaging, tissue engineering and therapeutics (Wang et al., 2016, Wei and Wang, 2013). Metal complexes as the representative have widely used in fabrication of immunosensors, because they could increase the sensing surface area and amplify the signal. MoS2, as two-dimensional layered group-VI transition metal dichalcogenides, has attracted increasing interest in catalysis, owing to the unique structure and properties such as semiconducting property, direct band gap and conductance. (Cao et al., 2012, Splendiani et al., 2010, Zhang et al., 2015). And the free energy of atomic hydrogen bonding to the sulfur edge of the MoS2 structure is approach to that of Pt, illustrating that MoS2 has a promising potential to substitute Pt-group catalysts (Ren et al., 2015). Zhu et al. (Zhu et al., 2016) integrated PtW nanocrystals and MoS2 nanosheets in conjunction with each other to detect H2O2, obtaining a high sensitivity. And Yoon's group (Yoon et al., 2017) synthesized MoS2 nanoparticle hybrid graphene oxide to catalyze H2O2, achieving satisfying results. Molybdenum disulfide functionalized MWCNTs synthesized in this work can control the size of MoS2 held together by van der Waals interactions and accelerate the electron transfer to improve the conductivity (Radisavljevic et al., 2011). Meanwhile, as the result of the enhanced physical, and chemical catalytic properties, bimetallic composite nanostructures, such as core-shell nanoparticles and nano-dendrites, enhanced catalytic activity and tolerability for oxygen reduction over the corresponding monometallic counterparts (Shi et al., 2013). And they can also accelerate reaction kinetics (Henning et al., 2013). Most importantly, bimetallic catalysts often displayed superior catalytic performance compared to their single metal counterparts, owing to synergistic effects between two metals (Enache et al., 2006). And a novel Au@Pd nanoparticles (Au@Pd NPs) synthesized was firstly used to further improve the sensitivity. Large numbers of catalytically active sites formed by the dendrite Au@Pd NPs efficiently facilitated oxygen reduction reaction (ORR) (Fujita et al., 2012, Huang et al., 2015). Meanwhile, Au@Pd NPs had wonderful biocompatibility with biomolecules, leading to load a larger number of Ab2 via the affinity interaction between Pd NPs and amine group of Ab2.
Hence, a novel and ultrasensitive sandwich-type electrochemical immunosensor was designed for quantitative HBeAg detection, using p-GO@Au as the sensing platform and Au@Pd/MoS2@MWCNTs as signal labels. The proposed immunosensor showed admirable linear range, low detection limit, excellent specificity, good reproducibility and acceptable stability.
Section snippets
Reagents and apparatus
The HBe antibody and antigen were supplied from Shanghai Linc-Bio Science Co., Ltd (Shanghai, China). Bovine serum albumin (BSA, 96–99%) was purchased from Sigma reagent Co., Ltd. (St. Louis, MO, USA). Multi-walled carbon nanotubes (MWCNTs) were purchased from Alfa Aesar Co., Ltd. (Shanghai, China). HAuCl4·4H2O was obtained from Sigma-Aldrich Co., Ltd. (Beijing, China). Ammonium thiomolybdate [(NH4)2MoS4] was obtained from J&K Scientific Ltd. (Beijing, China). cetyltrimethylammonium bromide
Characterization of the structure and morphology
Fig. 2A showed the SEM image of the p-GO@Au composites. Clearly, plenty of nanoparticles distributed on the surface and inside of GO porous composites evenly, with a mean diameter of 25 nm. And it was clear to see that obviously porous structures (inset in Fig. 2A) which further gave a high specific surface area for antibody attachment and large amounts of defects/functional groups for the growth of Au NPs (Li et al., 2017a, Li et al., 2017b, Li et al., 2017). More importantly, the internal
Conclusions
In this research, a novel immunosensor was proposed for ultrasensitive determination of HBeAg by loading Au@Pd nanoparticles on MoS2@MWCNTs as label to amplify the current signal. Using p-GO@Au as platform can enlarge the captured biomolecules and accelerate the electron transfer. Overall, the developed immunosensor possessed excellent specificity, good reproducibility and acceptable stability. The prepared immunosensor which exhibited excellent properties would provide a potential application
Acknowledgments
This study was financially supported by the National Natural Science Foundation of China (Nos. 21575079 and 21575050), and Natural Key Science Foundation of Shandong Province (ZR2013FB001). All of the authors express their deep thanks.
References (39)
- et al.
Carbon
(2008) - et al.
Biosens. Bioelectron.
(2017) - et al.
Appl. Catal. B: Environ.
(2015) - et al.
Anal. Chim. Acta
(2013) - et al.
Energy
(2014) - et al.
Biosens. Bioelectron.
(2015) - et al.
Carbon
(2010) - et al.
Int. J. Infect. Dis.
(2011) - et al.
Biosens. Bioelectron.
(2017) - et al.
Biosens. Bioelectron.
(2017)
Biosens. Bioelectron.
Hepatology
Biosens. Bioelectron.
Biosens. Bioelectron.
Anal. Chim. Acta
Biosens. Bioelectron.
Biosens. Bioelectron.
Nat. Commun.
Hum. Immunol.
Cited by (74)
Metal nanoparticles-assisted early diagnosis of diseases
2022, OpenNanoCitation Excerpt :Different nanomaterials in composite and hybrid systems have been shown to improve biosensor sensitivity. Furthermore, various metals in a nanoformulation enhance the number of reaction sites, resulting in higher reactions and lower LOD [154]. Several structures of nanomaterials have also been used in nanoformulation for the increment of the capability of the biosensor in the detection of biomarkers.
Current progress in organic–inorganic hetero-nano-interfaces based electrochemical biosensors for healthcare monitoring
2022, Coordination Chemistry Reviews