Article Cite This: ACS Appl. Bio Mater. XXXX, XXX, XXX−XXX
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Colorimetric Analysis of Carcinoembryonic Antigen Using Highly Catalytic Gold Nanoparticles-Decorated MoS2 Nanocomposites Shao Su,*,† Jing Li,† Yao Yao,† Qian Sun,† Qiang Zhao,† Fei Wang,‡ Qian Li,‡ Xiaoguo Liu,‡ and Lianhui Wang*,† †
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Key Laboratory for Organic Electronics and Information Displays (KLOEID) & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 210023, China ‡ School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China S Supporting Information *
ABSTRACT: Sensitive detection of carcinoembryonic antigen (CEA) is very important for early detection and cancer therapy monitoring. We utilized the highly catalytic activity of MoS2-gold nanoparticles (MoS2AuNPs) nanocomposites to construct a colorimetric immunoassay for CEA detection, which could catalyze sodium borohydride (NaBH4) to reduce 4-nitrophenol (4-NP) and make the yellow solution colorless. MoS2-AuNPs nanocomposites could efficiently load antibodies (Ab1 and Ab2) because of their good biocompatibility and high adsorption ability, forming Ab1-MoS2-AuNPs nanoprobes for capturing CEA and Ab2-MoS2-AuNPs nanoprobes for catalytic reaction. It should be pointed out that Ab2-MoS2-AuNPs nanoprobes retained high catalytic activity because no blocking agent was used to block the catalytic sites. After the formation of the classical “sandwich” structure, parts of Ab2MoS2-AuNPs nanoprobes remained in the supernatant after centrifugation, making the catalytic reaction occur and obtaining a colorless solution. As expected, a linear function between absorbance peak intensity and the logarithm of 5 pg/mL−10 ng/mL CEA was observed, and the detection limit was obtained as 0.5 pg/mL. This colorimetric immunosensor showed acceptable selectivity and repeatability for CEA detection, which could be successfully employed to detect CEA in serum. KEYWORDS: molybdenum disulfide, carcinoembryonic antigen, nanoprobe, colorimetric, immunosensor
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graphene,24 carbon nanotubes,25,26 and nanocomposites,27 have been widely employed to construct colorimetric sensors. For example, Shao et al. developed an enzyme-free pHindicator-linked immunosorbent assay (PILISA) for CEA detection based on carbon nitride nanosheets. They just only tuned pH value to obtained different colors, which generated from the pH indicator molecules. In this detection strategy, the colorimetric signal greatly depended on CEA concentration (0.5−100 ng/mL), and the detection limit of this immunosensor was 0.34 pg/mL.28 Zhu and co-worker constructed a colorimetric immunosensor by using the different affinity of antigen and antibody−antigen complex on gold nanoparticlesupported Bi2Se3 (Au/Bi2Se3) nanosheets to analyze CEA. A classical anti-CEA/CEA product was formed after the addition of target CEA, resulting in an immunocomplex dissociated from the Au/Bi2Se3 nanocomposite surface due to the weak affinity. The released immunocomplex made Au/Bi 2Se3
INTRODUCTION Early disease diagnosis is an efficient approach to reduce the risk of tumor-related diseases and prolong the life of patients.1,2 Therefore, high sensitivity and selectivity analysis of tumorrelated biomarkers is very important in early disease diagnosis.3−5 Carcinoembryonic antigen (CEA) is a universally used tumor biomarker, which has been extensively employed in medical examination to monitor people’s health.6 As we know, the high level of CEA generally imply the occurrence of some tumors in people’s body.7 On the concept of accurate detection of CEA, many methods have been successfully employed to detect CEA, including inductively coupled plasma mass spectrometry (ICPMS),8,9 electrochemiluminescence/ chemiluminescence,10,11 colorimetry,12,13 fluorescence,14,15 electrochemistry,16,17 and surface-enhanced Raman scattering (SERS).18,19 Among these detection methods, colorimetric method obtained extensive attention due to its charming properties, such as easy-to-operate, real-time, low-cost and onsite analysis.20,21 To improve the detection performance of colorimetric sensors, nanomaterials with exciting chemical/ physical properties, such as noble metal nanostructures,22,23 © XXXX American Chemical Society
Received: October 8, 2018 Accepted: December 6, 2018 Published: December 6, 2018 A
DOI: 10.1021/acsabm.8b00598 ACS Appl. Bio Mater. XXXX, XXX, XXX−XXX
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ACS Applied Bio Materials
Scheme 1. (A) Preparation of MoS2-AuNPs Nanohybrids and Ab-MoS2-AuNPs Nanoprobes and (B) Description of a Colorimetric Sensor for CEA Detection Based on MoS2-AuNPs Nanohybrids
synthesis, the as-designed MoS2-based nanohybrids were used to detect phenol with sensitivity and selectivity.40 As mentioned above, a few MoS2-based nanocomposites colorimetric sensors have been successfully constructed on the basis of their excellent catalytic activity. Herein, we constructed a colorimetric immunosensor for CEA detection by using gold nanoparticles-supported MoS2 nanosheet (MoS2-AuNPs). As shown in Scheme 1A, coating anti-CEA (Ab1) was assembled on the MoS2-AuNPs surface as a capture nanoprobe (Ab1MoS2-AuNPs), which was used to capture target CEA. It should be noted that Ab1-MoS2-AuNPs nanoprobes should be blocked with bovine serum albumin (BSA) to inhibit nonspecific adsorption. Labeling anti-CEA (Ab2)-decorated MoS2-AuNPs nanocomposites was used as detection nanoprobes (Ab2-MoS2-AuNPs) to catalyze 4-NP by NaBH4. No immunoreaction occurred without target CEA, leading to a great deal of Ab1-MoS2-AuNPs and Ab2-MoS2-AuNPs remaining in the supernatant after centrifugation (Scheme 1B). As a result, the obtained supernatant made the 4-NP +NaBH4 solution change colorless quickly. The reason was ascribed to the reduction reaction of 4-NP and NaBH4 was enhanced by the remained Ab2-MoS2-AuNPs. Classical “sandwich” immunocomplexes were formed after the addition of target CEA due to the antibody−antigen reaction, making a large number of Ab2-MoS 2 -AuNPs were removed by centrifugation. Therefore, the color of solution did not obviously change because the amount of Ab2-MoS2-AuNPs greatly decreased in the supernatant. In our detection strategy, the detection limit of as-designed immunosensor was estimated as 0.5 pg/mL.
nanocomposite possess catalytic activity, leading to facilitate the reduction reaction between 4-nitrophenol (4-NP) and NaBH4 and obtain a colorless solution. This colorimetric immunosensor displayed a detection limit of 160 pg/mL for CEA.29 Like other nanomaterials, molybdenum disulfide (MoS2) has been successfully explored in sensors, catalysts, energies, drug delivery, and therapy, which was attributed to its large surface area, easy functionalization, superior biocompatibility, and excellent catalytic activity.30,31 MoS2 is a member of twodimensional transition metal dichalcogenides with typical layered nanomaterial.32,33 MoS2 nanosheet possessed peroxidase-like activity, which could be used as an enzyme mimic. For instance, Chen et al. developed a colorimetric sensor for the detection of glyphosate by using MoS2 nanosheets. The proposed colorimetric sensor could determine as low as 0.087 μg/mL glyphosate.34 Similarly, Wang’s group and Chen’s group reported a MoS2 -based colorimetric sensor for trinitrotoluene and copper ions detection with high sensitivity and selectivity, respectively.35,36 In general, nanocomposites exhibit better chemical/physical properties than single component due to their synergistic effect. Inspired by this concept, researchers have hybridized noble metal nanoparticles with MoS2 to obtain MoS2-based nanocomposites. These asdesigned MoS2-based nanocomposites combine the advantage of MoS2 nanosheets with noble metal nanoparticles, enhancing their properties and enlarging their application fields.37,38 Nirala et al. developed a colorimetric sensor to detect cholesterol by using gold nanoparticles-decorated molybdenum disulfide nanoribbons (MoS2 NRs-AuNPs). The designed detection system showed excellent performance in wide temperature range (25−60 °C) and pH (3.0−6.0) due to the synergistic effect of MoS2 NRs-AuNPs nanocomposites.39 Another example was reported by Wang’s group. They supported uniform Pt3Au1 nanoparticles (NPs) on few-layer MoS2 nanosheets surface to improve the catalytic activity. After
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EXPERIMENTAL SECTION
Reagents and Chemicals. All the reagents and chemicals were listed in Supporting Information. Apparatus. Transmission electron microscope (TEM), zeta potential analyzer, atomic force microscope (AFM), dynamic light scattering (DLS), and UV−vis-NIR adsorption spectra were used to
B
DOI: 10.1021/acsabm.8b00598 ACS Appl. Bio Mater. XXXX, XXX, XXX−XXX
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ACS Applied Bio Materials characterize the formation of nanoprobes and monitor the whole catalytic reaction. Synthesis of MoS2 Nanosheets and MoS2-AuNPs Nanocomposites. MoS2 nanosheets and MoS2-AuNPs nanocomposites were synthesized on the basis of our published works,41,42 which were listed Supporting Information. Preparation of MoS2-Based Nanoprobes. The conjugation of anti-CEA and MoS2-AuNPs (Ab-MoS2-AuNPs) were performed according to the literature.16 In brief, the coating anti-CEA (Ab1) and labeling anti-CEA (Ab2) were assembled on MoS2-AuNPs nanocomposite to gain Ab1-MoS2-AuNPs and Ab2-MoS2-AuNPs nanoprobes, respectively, which were used to efficiently capture target CEA. First, 0.5 mL 11.0 mg/mL MoS2-AuNPs were mixed with 0.02 mL of 10 μg/mL anti-CEA and assembled overnight at 4 °C with gentle shaking. Then, BSA blocked unreacted sites to gain Ab1-MoS2AuNPs nanoprobes at 37 °C for 60 min. After that, the Ab1-MoS2AuNPs nanoprobes were purified by centrifugation twice (8000 rpm, 10 min, 4 °C). Finally, the Ab1-MoS2-AuNPs was redispersed in storage buffer solutions and stored in a refrigerator. The Ab2-MoS2AuNPs nanoprobes were prepared using the similar procedure. To retain the catalytic ability of MoS2-AuNPs nanocomposites, Ab2MoS2-AuNPs nanoprobes did not be blocked by BSA. Detection of CEA. At first, 0.02 mL carcinoembryonic antigen (CEA) at different concentrations was added into the Ab1-MoS2AuNPs solution and incubated at 37 °C for 120 min by using low shaking speed. Then, the obtained product was purified by centrifugation twice (8000 rpm, 10 min) and redissolved in 0.3 mL storage buffer. Next, Ab2-MoS2-AuNPs were incubated with CEAAb1-MoS2-AuNPs to form the classical “sandwich” structure for 2 h at 37 °C. The immunoreaction product was purified at 3500 rpm for 3 min.43 It was noted that both the product and the supernatant were collected. At last, the supernatant was added into the 3 mL mixture solution containing 0.09 mM 4-nitrophenol (4-NP) and 0.65 M sodium borohydride (NaBH4). The color of the mixture solution greatly depended on the remaining amount of Ab2-MoS2-AuNPs nanoprobes in the supernatant, which could enhance the reaction of 4-NP and NaBH4.
Figure 2. (A) Zeta potential of MoS2, MoS2-AuNPs, Ab-MoS2AuNPs, immune product, and anti-CEA. Size distribution of (B) AbMoS2-AuNPs and (C) immune product.
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RESULTS AND DISCUSSION Characterization of MoS2 Nanosheets and MoS2AuNPs Nanocomposites. As exhibited in Figure 1A, the obtained MoS2 nanosheets displayed a typical layered
Figure 3. (A) UV−vis results of 4-NP+NaBH4 mixture reacted with different concentrations of MoS2-AuNPs. (B) The peak intensities at 300 and 400 nm versus the various concentrations of MoS2-AuNPs in (A). (C) The catalytic performance of MoS2-AuNPs assembled with different anti-CEA concentration. (D) The peak intensities at 300 and 400 nm versus anti-CEA-MoS2-AuNPs in (C).
nanostructure with the wrinkle and crumple. After adding HAuCl4, plenty of 15 nm Au NPs were supported uniformly on the surface of MoS2 nanosheets (Figure 1B). Figure 1C showed the UV−vis results of MoS2 nanosheets and MoS2AuNPs nanocomposites. A new absorption peak was observed at 538 nm in MoS2-AuNPs nanocomposites, owing to the characteristic absorption of AuNPs. In the figure, MoS2-AuNPs nanocomposites solution was mulberry, while MoS2 nanosheets was gray-brown (photos in Figure 1C). Moreover, the height of MoS2-AuNPs nanocomposites (Figure S2B) was higher than that of MoS2 nanosheets (Figure S2A), which were characterized by AFM. All experimental data proved that MoS2-AuNPs nanocomposites were prepared successfully. In this work, we employed the 4-NP+NaBH4 reaction strategy to test the catalytic ability of obtained MoS2-AuNPs nanocomposites. As we know, 4-NP solution is pale yellow (Figure 1D, photo a) and has an absorption peak at about 317 nm (Figure 1D, curve a). Once freshly prepared NaBH4 was
Figure 1. TEM results of (A) MoS2 nanosheets and (B) MoS2-AuNPs nanocomposites. Inset: the statistical data of AuNPs’ diameter. (C) UV−vis results and photos of (a) MoS2 nanosheets and (b) MoS2AuNPs nanocomposites. (D) UV−vis data and corresponding color photographs of (a) 4-NP, (b) 4-NP+NaBH4, and (c) 4-NP +NaBH4+MoS2-AuNPs. C
DOI: 10.1021/acsabm.8b00598 ACS Appl. Bio Mater. XXXX, XXX, XXX−XXX
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absorption peak appeared at 400 nm, which was attributed to the reaction product of p-nitrophenolate (Figure 1D, curve b). After the addition of MoS2-AuNPs nanocomposites, the yellow solution easily turned to colorless with the occurrence of catalytic reaction (Figure 1D, photo c). Excess NaBH4 could efficiently reduce 4-NP to 4-aminophenol (4-AP) with the help of MoS2-AuNPs nanocomposites. Meanwhile, the absorbance intensity at 400 nm decreased while a small absorption band was obtained at 300 nm (Figure 1D, curve c). Characterization of Ab-MoS2-AuNPs Nanocomposites and Immunocomplexes. To prove the formation of Ab-MoS2-AuNPs nanocomposites, the zeta potential and dynamic diameters of MoS2-based nanoprobes and immunoreaction product were studied. As exhibited in Figure 2A, the zeta potential of Ab-MoS2-AuNPs nanoprobes was −45.87 mV, which was more negative than MoS2 (−20.13 mV) and MoS2-AuNPs (−30.21 mV), respectively, proving that AbMoS2-AuNPs nanoprobes were successfully formed. Such obvious negative shift was ascribed to the loading of antiCEA (−16.19 mV) on MoS2-AuNPs nanocomposites. A classical sandwich structure was obtained after the addition of CEA, resulting in the zeta potential being negatively shifted to −89.32 mV. Subsequently, the size of Ab-MoS2-AuNPs nanoprobes and immunoreaction product were also investigated. It can be seen that the size of sandwich structures (Figure 2C, 932.3 nm) was 3 times that of Ab-MoS2-AuNPs (Figure 2B, 291.8 nm), suggesting the formation of immune product. Surface-enhanced Raman scattering (SERS, Figure S1) and AFM (Figure S2) were utilized to further characterize the successful preparation of nanoprobes and immune product. According to the above analysis, it can be concluded that the designed nanoprobes and immune structure had been constructed. Optimization of Experimental Conditions. For obtaining the better detection capability, we optimized the concentration of MoS2-AuNPs and the concentration of antibody loaded on MoS2-AuNPs surface. It had been proved that MoS2-AuNPs nanocomposites could catalyze reaction strategy of 4-AP+NaBH4. Therefore, the effect of MoS2-AuNPs nanocomposites concentration on catalytic performance should be studied. As shown in Figure 3A, the 4-nitrophenolate anion (400 nm) peak intensity decreased, and the 4AP (300 nm) peak intensity increased with the increasing added concentration of MoS2-AuNPs nanocomposites ranging from 0.0 to 11.0 mg/mL (Figure 3B), respectively. If the concentration of MoS2-AuNPs nanocomposites continually increased to 22.0 mg/mL, the change of absorption peaks at 400 and 300 nm almost reached a plateau. Therefore, we chose 11.0 mg/mL MoS2-AuNPs nanocomposites in the following experiments. As we know, antibody adsorbed on the surface of MoS2-AuNPs nanocomposites would hinder the catalytic activity of MoS2-based nanocomposites. In our detection strategy, the ideal Ab2-MoS2-AuNPs nanoprobes not only loaded enough anti-CEA to recognize target CEA but also had a large number of catalytic sites to facilitate conversion 4-NP to 4-AP. Therefore, the anti-CEA concentration loaded on MoS2AuNPs nanocomposites was tested. Figure 3C exhibited the catalytic performance of Ab2-MoS2-AuNPs nanoprobes. The catalytic ability of Ab2-MoS2-AuNPs nanoprobes decreased with the increasing concentration of anti-CEA, corresponding to 4-AP peak intensity (300 nm) decreased obviously (Figure 3D). Moreover, the peak intensity at 400 nm did not obviously decrease when high anti-CEA concentration loaded on MoS2-
Figure 4. UV−vis data of 4-NP+NaBH4 mixture catalyzed by (A) AuNPs, (B) MoS2-AuNPs, and (C) anti-CEA-MoS2-AuNPs. (D) Time-dependent peak intensity changes of 4-NP reaction solution (400 nm) catalyzed by MoS2, AuNPs, anti-CEA-MoS2-AuNPs, and MoS2-AuNPs.
Figure 5. (A) UV−vis results of 4-NP+NaBH4 reaction strategy catalyzed by Ab2-MoS2-AuNPs in the presence of different CEA concentrations. (B) A curve of absorption signals at 400 nm changed with the logarithm of 5 pg/mL−10 μg/mL CEA. Inset: absorption signals was linear with the logarithm values of 5 pg/mL−10 ng/mL CEA. (C) Photographs of different CEA concentrations in our detection strategy.
Figure 6. Selectivity evaluation of this colorimetric approach toward the detection of CEA. Plots of change in absorbance at 400 nm versus different tumor markers at the same concentration (CEA, AFP, BSA, IgG, NSE, and PSA). The photograph of as-prepared immunosensor for CEA, AFP, BSA, IgG, NSE, and PSA detection.
added into the 4-NP solution, the pale yellow solution immediately turned to bright yellow, and some bubbles were generated (Figure 1D, photo b). It was noted that a new D
DOI: 10.1021/acsabm.8b00598 ACS Appl. Bio Mater. XXXX, XXX, XXX−XXX
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ACS Applied Bio Materials Table 1. Analysis of CEA Using As-Designed Colorimetric Immunosensor (n = 3) sample
added (pg/mL)
found (pg/mL)
RSD (%)
recovery (%)
1 2 3
50 100 10000
46.42, 51.45, 51.45 95.47, 90.68, 100.52 9846.65, 9846.65, 10915.19
5.84 5.15 6.05
99.55 95.55 102.03
NP+NaBH4 mixture solution was agreement with the UV−vis adsorption spectra. As mentioned above, these changes of absorption peaks (400 and 300 nm) and the solution color were ascribed to the occurrence of catalytic reaction with the help of Ab2-MoS2-AuNPs nanoprobes. A lower concentration CEA added in our detection strategy, resulting in more Ab2MoS2-AuNPs nanoprobes remaining in the supernatant. Therefore, the remaining Ab2-MoS2-AuNPs nanoprobes could facilitate the reduction reaction of 4-NP+NaBH4, leading to reaction solution changed to colorless. Figure 5B showed that the curve of absorption signals at 400 nm changed with the logarithm of 5 pg/mL−10 μg/mL CEA. It was noted that the absorption signals (400 nm) were linear with the logarithm of 5 pg/mL−10 ng/mL CEA (Figure 5B, inset) with a detection limit of 0.5 pg/mL. Such CEA detection performance included linear range and detection limit was compared with other colorimetric immunosensors, which was listed in Table S1.49,50 Selectivity the MoS2-Based Colorimetric Immunosensor. Selectivity was another important factor of an immunosensor. Therefore, AFP, BSA, IgG, NSE, and PSA were chosen as interfering substance to test the antiinterference ability of our designed colorimetric immunosensor. As shown in Figure 6, the peak intensity of CEA was about 4.9, 4.5, 4.6, 4.6, and 4.1 times that of AFP, BSA, IgG, NSE, and PSA at the same concentration, respectively. Such results proved that the as-designed colorimetric immunosensor could efficiently distinguish CEA from other antigens. The photograph for CEA, AFP, BSA, IgG, NSE, and PSA detection further proved this conclusion, which was inset in Figure 6. Real Sample Analysis. For evaluating the practicability of this colorimetric immunosensor in complex fluids, we utilized a standard addition method to analyze CEA in diluted serum samples. We tested three different concentrations of CEA by this colorimetric immunosensor, and the detailed data were listed Table 1. Low relative standard deviation (RSD, ∼ 6%) and high recovery (>95%) of this colorimetric immunosensor were obtained, indicating that our proposed immunosensor had considerably potential applications in real samples.
AuNPs nanocomposites, suggesting more assembled anti-CEA brought lower catalytic activity again. The conclusion was drawn that the active catalytic sites of MoS2-AuNPs nanocomposites were efficiently blocked with anti-CEA. If the antibody concentration was over 10.0 μg/mL, the catalytic activity of Ab-MoS2-AuNPs nanoprobes was significantly inhibited. Considering the capture efficient and catalytic activity, 10.0 μg/mL antibody was chosen to incubate with MoS2-AuNPs nanocomposites. Kinetic Study. Kinetic parameter was an important factor to judge the catalytic speed of four nanocatalysts for the reaction of 4-NP+NaBH4.44 At first, the catalytic performance of nanocatalysts was judged by the time of the catalytic reduction reaction. As previous works reported, MoS 2 nanosheets also possessed catalytic activity toward 4-NP reduction.45−47 Unfortunately, MoS2 nanosheets needed 680 s to accomplish the reduction reaction (Figure S3). In comparison, the reaction time of AuNPs (Figure 4A), MoS2AuNPs (Figure 4B), and Ab2-MoS2-AuNPs (Figure 4C) were 420, 200, and 240 s, respectively. It was noted that the reaction time of MoS2-AuNPs was less than that of AuNPs and Ab2MoS2-AuNPs, indicating that MoS2-AuNPs had better catalytic activity. The higher catalytic ability was ascribed to the synergistic effect of MoS2-AuNPs nanocomposites.48 First, MoS2 nanosheets possessed large surface area, which was beneficial to adsorb large amounts of 4-NP via π−π bond. Such enrichment action could efficiently increase the concentration of reactants near the catalyst and then facilitated the catalytic reaction. Second, MoS2 nanosheet was used as a substrate to prevent AuNPs from agglomerating, which could efficiently retain the catalytic quality of AuNPs. Third, both AuNPs and MoS2 nanosheets could facilitate this catalytic reaction. However, anti-CEA blocked the catalytic sites of MoS2AuNPs when anti-CEA loaded on MoS2-AuNPs, resulting in the catalytic activity decreased. Because NaBH4 concentration in this catalytic system was excess, we used a pseudo-first-order reaction to investigate the catalytic performances of four nanocatalysts. It is well-known that kinetic equation is listed as ln (Ct/C0) = ln (At/A0) = −kappt. On the basis of experimental results, the value of ln (At/A0) was greatly dependent on reaction time t, which was obtained in Figure 4D. It could be observed that kapp values of MoS2, AuNPs, MoS2-AuNPs, antiCEA-MoS2-AuNPs were −0.0020 s−1, −0.0054 s−1, −0.0158 s−1, and −0.0132 s−1, respectively. The experimental data further proved MoS2-AuNPs had the best catalytic activity and anti-CEA-MoS2-AuNPs still retained excellent catalytic activity in our detection strategy. Detection Performance of Our Colorimetric Immunosensor. On the basis of highly catalytic activity of Ab2MoS2-AuNPs nanoprobes, we developed a colorimetric immunosensor for CEA detection. As noted, the absorption signals at 400 nm decreased with the decreasing concentration of target CEA, corresponding to the increased peak intensity at 300 nm (Figure 5A). The photographs of different concentration of CEA in our detection strategy was also observed in Figure 5C. The corresponding color change of 4-
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CONCLUSIONS
In summary, we constructed a simple, sensitive colorimetric immunosensor for CEA detection based on MoS2-AuNPs nanohybrids. Due to the synergistic effect, MoS2-AuNPs nanocomposites possessed high catalytic ability, which could facilitate the reaction of 4-NP+NaBH4 accompanied with the yellow solution turning colorless. On the basis of this phenomenon, MoS2-AuNPs nanocomposites were employed as nanoprobes to detect CEA ranging from 5 pg/mL−10 ng/ mL. Moreover, this as-prepared colorimetric immunosensor also had excellent selectivity, which could efficiently distinguish CEA from other proteins. Obviously, MoS2-AuNPs nanocomposites may be a potential candidate to prepare colorimetric sensors for target molecules detection. E
DOI: 10.1021/acsabm.8b00598 ACS Appl. Bio Mater. XXXX, XXX, XXX−XXX
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Nanoparticles and Dynamic Light Scattering. Sens. Actuators, B 2014, 191, 396−400. (8) Chen, B.; Hu, B.; Jiang, P.; He, M.; Peng, H.; Zhang, X. Nanoparticle Labelling-based Magnetic Immunoassay on Chip Combined with Electrothermal Vaporization-inductively Coupled Plasma Mass Spectrometry for the Determination of Carcinoembryonic Antigen in Human Serum. Analyst 2011, 136, 3934−3942. (9) Liu, R.; Liu, X.; Tang, Y.; Wu, L.; Hou, X.; Lv, Y. Highly Sensitive Immunoassay Based on Immunogold-silver Amplification and Inductively Coupled Plasma Mass Spectrometric Detection. Anal. Chem. 2011, 83, 2330−2336. (10) Pang, X.; Li, J.; Zhao, Y.; Wu, D.; Zhang, Y.; Du, B.; Ma, H.; Wei, Q. Label-Free Electrochemiluminescent Immunosensor for Detection of Carcinoembryonic Antigen Based on Nanocomposites of GO/MWCNTs-COOH/Au@CeO2. ACS Appl. Mater. Interfaces 2015, 7, 19260−19267. (11) Zong, C.; Wu, J.; Wang, C.; Ju, H.; Yan, F. Chemiluminescence Imaging Immunoassay of Multiple Tumor Markers for Cancer Screening. Anal. Chem. 2012, 84, 2410−2415. (12) Li, B.; Lai, G.; Lin, B.; Yu, A.; Yang, N. Enzyme-induced Biomineralization of Cupric Subcarbonate for Ultrasensitive Colorimetric Immunosensing of Carcinoembryonic Antigen. Sens. Actuators, B 2018, 262, 789−795. (13) Li, C.; Yang, Y.; Wu, D.; Li, T.; Yin, Y.; Li, G. Improvement of Enzyme-linked Immunosorbent Assay for the Multicolor Detection of Biomarkers. Chem. Sci. 2016, 7, 3011−3016. (14) Tian, J.; Zhou, L.; Zhao, Y.; Wang, Y.; Peng, Y.; Zhao, S. Multiplexed Detection of Tumor Markers with Multicolor Quantum Dots Based on Fluorescence Polarization Immunoassay. Talanta 2012, 92, 72−77. (15) Wu, J.; Fu, Z.; Yan, F.; Ju, H. Biomedical and Clinical Applications of Immunoassays and Immunosensors for Tumor Markers. TrAC, Trends Anal. Chem. 2007, 26, 679−688. (16) Su, S.; Han, X.; Lu, Z.; Liu, W.; Zhu, D.; Chao, J.; Fan, C.; Wang, L.; Song, S.; Weng, L.; Wang, L. Facile Synthesis of a MoS2Prussian Blue Nanocube Nanohybrid-Based Electrochemical Sensing Platform for Hydrogen Peroxide and Carcinoembryonic Antigen Detection. ACS Appl. Mater. Interfaces 2017, 9, 12773−12781. (17) Su, S.; Zou, M.; Zhao, H.; Yuan, C.; Xu, Y.; Zhang, C.; Wang, L.; Fan, C.; Wang, L. Shape-Controlled Gold Nanoparticles Supported on MoS2 Nanosheets: Synergistic Effect of Thionine and MoS2 and Their Application for Electrochemical Label-free Immunosensing. Nanoscale 2015, 7, 19129−19135. (18) Song, C.; Min, L.; Zhou, N.; Yang, Y.; Yang, B.; Zhang, L.; Su, S.; Wang, L. Ultrasensitive Detection of Carcino-embryonic Antigen by Using Novel Flower-like Gold Nanoparticle SERS Tags and SERSactive Magnetic Nanoparticles. RSC Adv. 2014, 4, 41666−41669. (19) Song, C.; Yang, Y.; Yang, B.; Min, L.; Wang, L. Combination Assay of Lung Cancer Associated Serum Markers Using Surfaceenhanced Raman Spectroscopy. J. Mater. Chem. B 2016, 4, 1811− 1817. (20) Sun, J.; Ge, J.; Liu, W.; Lan, M.; Zhang, H.; Wang, P.; Wang, Y.; Niu, Z. Multi-enzyme Co-Embedded Organic−inorganic Hybrid Nanoflowers: Synthesis and Application as A Colorimetric Sensor. Nanoscale 2014, 6, 255−262. (21) Chen, L.; Li, J.; Chen, L. Colorimetric Detection of Mercury Species Based on Functionalized Gold Nanoparticles. ACS Appl. Mater. Interfaces 2014, 6, 15897−15904. (22) Si, P.; Chen, L.; Yu, L.; Zhao, B. Dual Colorimetric and Conductometric Responses of Silver-Decorated Polypyrrole Nanowires for Sensing Organic Solvents of Varied Polarities. ACS Appl. Mater. Interfaces 2018, 10, 29227−29232. (23) Yao, G.; Pei, H.; Li, J.; Zhao, Y.; Zhu, D.; Zhang, Y.; Lin, Y.; Huang, Q.; Fan, C. Clicking DNA to Gold Nanoparticles: PolyAdenine-Mediated Formation of Monovalent DNA-Gold Nanoparticle Conjugates with Nearly Quantitative Yield. NPG Asia Mater. 2015, 7, No. e159. (24) Xu, H.; Wang, D.; He, S.; Li, J.; Feng, B.; Ma, P.; Xu, P.; Gao, S.; Zhang, S.; Liu, Q.; Lu, J.; Song, S.; Fan, C. Graphene-based
ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsabm.8b00598. Surface-enhanced Raman scattering and AFM results of MoS2 nanosheets, MoS2-AuNPs nanocomposites, Ab2MoS2-AuNPs nanoprobes and immune product, UV−vis data of the reduction of 4-NP+NaBH4 catalyzed by MoS2 nanosheet and the comparison of different nanomaterials-based colorimetric sensors for CEA detection (PDF)
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AUTHOR INFORMATION
Corresponding Authors
*E-mail:
[email protected]. Tel.: +86 25 85866333. *E-mail:
[email protected]. ORCID
Shao Su: 0000-0002-9399-8249 Qiang Zhao: 0000-0002-3788-4757 Qian Li: 0000-0002-1166-6583 Xiaoguo Liu: 0000-0002-7834-399X Lianhui Wang: 0000-0001-9030-9172 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This work was supported by the National Key Research and Development Program of China (2017YFA0205302), the National Natural Science Foundation of China (61671250, 21475064, and 21305070), the Program for Changjiang Scholars and Innovative Research Team in University (IRT_15R37), the Key Research and Development Program of Jiangsu (BE2018732), and the Natural Science Key Fund for Colleges and Universities in Jiangsu Province (17KJA430011).
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REFERENCES
(1) Yang, F.; Zuo, X.; Li, Z.; Deng, W.; Shi, J.; Zhang, G.; Huang, Q.; Song, S.; Fan, C. A Bubble-Mediated Intelligent Microscale Electrochemical Device for Single-step Quantitative Bioassays. Adv. Mater. 2014, 26, 4671−4676. (2) Qu, X.; Zhang, H.; Chen, H.; Aldalbahi, A.; Li, L.; Tian, Y.; Weitz, D. A.; Pei, H. Convection-Driven Pull-Down Assays in Nanoliter Droplets Using Scaffolded Aptamers. Anal. Chem. 2017, 89, 3468−3473. (3) Chen, P.; Pan, D.; Fan, C.; Chen, J.; Huang, K.; Wang, D.; Zhang, H.; Li, Y.; Feng, G.; Liang, P.; He, L.; Shi, Y. Gold Nanoparticles for High-throughput Genotyping of Long-range Haplotypes. Nat. Nanotechnol. 2011, 6, 639−644. (4) Ge, Z.; Pei, H.; Wang, L.; Song, S.; Fan, C. Electrochemical Single Nucleotide Polymorphisms Genotyping on Surface Immobilized Three-dimensional Branched DNA Nanostructure. Sci. China: Chem. 2011, 54, 1273−1276. (5) Chen, L.; Chao, J.; Qu, X.; Zhang, H.; Zhu, D.; Su, S.; Aldalbahi, A.; Wang, L.; Pei, H. Probing Cellular Molecules with PolyA-Based Engineered Aptamer Nanobeacon. ACS Appl. Mater. Interfaces 2017, 9, 8014−8020. (6) Qu, X.; Wang, S.; Ge, Z.; Wang, J.; Yao, G.; Li, J.; Zuo, X.; Shi, J.; Song, S.; Wang, L.; Li, L.; Pei, H.; Fan, C. Programming Cell Adhesion for On-Chip Sequential Boolean Logic Functions. J. Am. Chem. Soc. 2017, 139, 10176−10179. (7) Miao, X.; Zou, S.; Zhang, H.; Ling, L. Highly Sensitive Carcinoembryonic Antigen Detection Using Ag@Au Core−shell F
DOI: 10.1021/acsabm.8b00598 ACS Appl. Bio Mater. XXXX, XXX, XXX−XXX
Article
ACS Applied Bio Materials
with in Situ Grown Gold Nanoparticles. ACS Appl. Mater. Interfaces 2014, 6, 18735−18741. (42) Su, S.; Cao, W.; Liu, W.; Lu, Z.; Zhu, D.; Chao, J.; Weng, L.; Wang, L.; Fan, C.; Wang, L. Dual-mode Electrochemical Analysis of MicroRNA-21 Using Gold Nanoparticle-Decorated MoS2 Nanosheet. Biosens. Bioelectron. 2017, 94, 552−559. (43) Jin, L.; He, G.; Xue, J.; Xu, T.; Chen, H. Cu/Graphene with High Catalytic Activity Prepared by Glucose Blowing for Reduction of p-Nitrophenol. J. Cleaner Prod. 2017, 161, 655−662. (44) Li, H.; Han, L.; Cooper-White, J. J.; Kim, I. A General and Efficient Method for Decorating Graphene Sheets with Metal Nanoparticles Based on the Non-Covalently Functionalized Graphene Sheets with Hyperbranched Polymers. Nanoscale 2012, 4, 1355− 1361. (45) Meng, N.; Cheng, J.; Zhou, Y.; Nie, W.; Chen, P. Green Synthesis of Layered 1T-MoS2/Reduced Graphene Oxide Nanocomposite with Excellent Catalytic Performances for 4-Nitrophenol Reduction. Appl. Surf. Sci. 2017, 396, 310−318. (46) Jeyapragasam, T.; J, M. D.; V, G. Molybdenum Disulfide-Based Modifier for Electrochemical Detection of 4-Nitrophenol. Ionics 2018, 24, 4033. (47) Guardia, L.; Paredes, J. I.; Munuera, J. M.; Villar-Rodil, S.; Ayán-Varela, M.; Martínez-Alonso, A.; Tascón, J. M. D. Chemically Exfoliated MoS2 Nanosheets as an Efficient Catalyst for Reduction Reactions in the Aqueous Phase. ACS Appl. Mater. Interfaces 2014, 6, 21702−21710. (48) Wu, X.; Lu, C.; Zhou, Z.; Yuan, G.; Xiong, R.; Zhang, X. Green Synthesis and Formation Mechanism of Cellulose NanocrystalSupported Gold Nanoparticles with Enhanced Catalytic Performance. Environ. Sci.: Nano 2014, 1, 71−79. (49) Han, J.; Ma, J.; Ma, Z. One-step synthesis of graphene oxidethionine-Au nanocomposites and its application for electrochemical immunosensing. Biosens. Bioelectron. 2013, 47, 243−247. (50) Lin, D.; Wu, J.; Ju, H.; Yan, F. Nanogold/mesoporous carbon foam-mediated silver enhancement for graphene-enhanced electrochemical immunosensing of carcinoembryonic antigen. Biosens. Bioelectron. 2014, 52, 153−158.
Nanoprobes and A Prototype Optical Biosensing Platform. Biosens. Bioelectron. 2013, 50, 251−255. (25) Song, Y.; Xu, C.; Wei, W.; Ren, J.; Qu, X. Light Regulation of Peroxidase Activity by Spiropyran Functionalized Carbon Nanotubes Used for Label-free Colorimetric Detection of Lysozyme. Chem. Commun. 2011, 47, 9083−9085. (26) Zhang, Q.; Zhao, B.; Yan, J.; Song, S.; Min, R.; Fan, C. Nanotube-based Colorimetric Probe for Ultrasensitive Detection of Ataxia Telangiectasia Mutated Protein. Anal. Chem. 2011, 83, 9191− 9196. (27) Li, J.; Liu, C.; Liu, Y. Au/Graphene Hydrogel: Synthesis, Characterization and Its Use for Catalytic Reduction of 4-Nitrophenol. J. Mater. Chem. 2012, 22, 8426−8430. (28) Shao, F.; Jiao, L.; Miao, L.; Wei, Q.; Li, H. A pH Indicatorlinked Immunosorbent Assay Following Direct Amplification Strategy for Colorimetric Detection of Protein Biomarkers. Biosens. Bioelectron. 2017, 90, 1−5. (29) Xiao, L.; Zhu, A.; Xu, Q.; Chen, Y.; Xu, J.; Weng, J. Colorimetric Biosensor for Detection of Cancer Biomarker by Au Nanoparticle-Decorated Bi2Se3 Nanosheets. ACS Appl. Mater. Interfaces 2017, 9, 6931−6940. (30) Yang, T.; Yang, R.; Chen, H.; Nan, F.; Ge, T.; Jiao, K. Electrocatalytic Activity of Molybdenum Disulfide Nanosheets Enhanced by Self-doped Polyaniline for Highly Sensitive and Synergistic Determination of Adenine and Guanine. ACS Appl. Mater. Interfaces 2015, 7, 2867−2872. (31) Zhong, R.; Tang, Q.; Wang, S.; Zhang, H.; Zhang, F.; Xiao, M.; Man, T.; Qu, X.; Li, L.; Zhang, W.; Pei, H. Self-Assembly of EnzymeLike Nanofibrous G-Molecular Hydrogel for Printed Flexible Electrochemical Sensors. Adv. Mater. 2018, 30, 1706887. (32) Li, X.; Shan, J.; Zhang, W.; Su, S.; Yuwen, L.; Wang, L. Recent Advances in Synthesis and Biomedical Applications of TwoDimensional Transition Metal Dichalcogenide Nanosheets. Small 2017, 13, 1602660. (33) Cui, X.; Chen, H.; Yang, T. Research Progress on the Preparation and Application of Nano-Sized Molybdenum Disulfide. Huaxue Xuebao 2016, 74, 392−400. (34) Chen, Q.; Chen, H.; Li, Z.; Pang, J.; Lin, T.; Guo, L.; Fu, F. Colorimetric Sensing of Glyphosate in Environmental Water Based on Peroxidase Mimetic Activity of MoS2 Nanosheets. J. Nanosci. Nanotechnol. 2017, 17, 5730−5734. (35) Wang, Y.; He, Y.; Peng, R.; Chu, S. Facile Colorimetric Assay for Trinitrotoluene Based on the Intrinsic Peroxidase-Like Activity of MoS2 Nanosheets. Anal. Methods 2017, 9, 2939−2946. (36) Chen, H.; Li, Z.; Liu, X.; Zhong, J.; Lin, T.; Guo, L.; Fu, F. Colorimetric Assay of Copper Ions Based on the Inhibition of Peroxidase-Like Activity of MoS2 Nanosheets. Spectrochim. Acta, Part A 2017, 185, 271−275. (37) Yuwen, L.; Xu, F.; Xue, B.; Luo, Z.; Zhang, Q.; Bao, B.; Su, S.; Weng, L.; Huang, W.; Wang, L. General Synthesis of Noble Metal (Au, Ag, Pd, Pt) Nanocrystal Modified MoS2 Nanosheets and the Enhanced Catalytic Activity of Pd-MoS2 for Methanol Oxidation. Nanoscale 2014, 6, 5762−5769. (38) Qiao, X.; Zhang, Z.; Tian, F.; Hou, D.; Tian, Z.; Li, D.; Zhang, Q. Enhanced Catalytic Reduction of p-Nitrophenol on Ultrathin MoS2 Nanosheets Decorated with Noble Metal Nanoparticles. Cryst. Growth Des. 2017, 17, 3538−3547. (39) Nirala, N. R.; Pandey, S.; Bansal, A.; Singh, V. K.; Mukherjee, B.; Saxena, P. S.; Srivastava, A. Different Shades of Cholesterol: Gold Nanoparticles Supported on MoS2 Nanoribbons for Enhanced Colorimetric Sensing of Free Cholesterol. Biosens. Bioelectron. 2015, 74, 207−213. (40) Cai, S. F.; Han, Q. S.; Qi, C.; Wang, X. H.; Wang, T.; Jia, X. H.; Yang, R.; Wang, C. MoS2-Pt3Au1 Nanocomposites with Enhanced Peroxidase-Like Activities for Selective Colorimetric Detection of Phenol. Chin. J. Chem. 2017, 35, 605−612. (41) Su, S.; Zhang, C.; Yuwen, L.; Chao, J.; Zuo, X.; Liu, X.; Song, C.; Fan, C.; Wang, L. Creating SERS Hot Spots on MoS2 Nanosheets G
DOI: 10.1021/acsabm.8b00598 ACS Appl. Bio Mater. XXXX, XXX, XXX−XXX
