Detection Of Squamous Cell Carcinoma Antigen Research Articles

Ultrasensitive detection of SCCA employing a graphene oxide integrated microfiber ring laser biosensor

Squamous cell carcinoma antigen (SCCA) is one of the most commonly detected cancer biomarkers for a variety of cancers. In this paper, a microfiber ring laser biosensor with a graphene oxide linking layer for SCCA detection was proposed and experimentally demonstrated. SCCA antibody immobilized on graphene oxide surface binds specifically to SCCA, and induces refractive index variation over the surface of the microfiber biosensor, which leads to a wavelength shift of the microfiber ring laser biosensor. The experimental results show that the proposed laser biosensor can detect SCCA with concentrations from 0.01 to 50 ng/mL, and the calculated detection limit can be as low as 1.3 pg/mL. Additionally, the label-free quantitative detection of SCCA using the proposed microfiber biosensor was verified experimentally according to the corresponding regression equation, and the results agree well with clinical examination detection. This constructed microfiber biosensor may have promising practical applications in analytical detection, medical diagnostics, etc.

Determination of the cervical cancer biomarker SCCA using CMK-3@UiO-66@AuNPs composite-modified glassy carbon electrodes

In order to detect the cervical cancer biomarker squamous cell carcinoma antigen (SCCA) in human serum, an electrochemical immunosensor was constructed. Zirconium 1,4-dicarboxybenzene MOF (UiO-66), with a high specific surface area, was coupled with gold nanoparticles (AuNPs), creating the UiO-66@AuNPs nanomaterial. This coupling increased the sensitivity of the electrochemical immunosensor by providing many biological binding sites for antibodies to bind to Au-S bonds. Then, mesoporous carbon (CMK-3) was added to the UiO-66@AuNPs nanomaterial to obtain a CMK-3@UiO-66@AuNPs nanocomposite. This further increased the electron transfer proficiency of the material and enhanced the electrochemical signal. Finally, the sensitive detection of squamous cell carcinoma antigen (SCCA) was made possible by unique immunological responses between antigens and antibodies. Transmission electron microscopy (TEM) analysis of CMK-3@UiO-66@AuNPs revealed embedded surfaces and voids; cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirmed the successful assembly of the electrochemical immunosensor. The developed electrochemical immunosensor demonstrated good linearity (R12 = 0.999) from 0.01 pg/mL to 10,000 pg/mL, which is the concentration range of SCCA in human serum. The limit of detection was 0.0034 pg/mL (at an S/N ratio of 3). The immunosensor exhibited excellent precision, stability and selectivity, with a high rate of recovery (98.26–101.8 %). The experimental validation studies demonstrated that the electrochemical immunosensor was effective for the detection of SCCA in human serum, offering a novel method for the early diagnosis and dynamic surveillance of cervical cancer.

Sandwich-Like Electrochemical Immunosensing of Squamous Cell Carcinoma Antigen Based on Gold Nanoparticles/Reduced Graphene and Toluidine Blue/UIO-66-NH2

Squamous cell carcinoma antigen (SCCA) is an important biomarker in the diagnose of cancer, so developing effective methods for its detection is of great significance. In the present work, a novel sandwich-like electrochemical immunosensing assay (STEM) of SCCA was constructed by preparing gold nanoparticle/reduced graphene-oxide (Au NPs/rGO) to immobilize primary antibody (PAb) of SCCA and UIO-66-NH2 MOFs structure to immobilize second antibody (SAb) and electroactive toluidine blue (Tb) probe. In this designed STEM assay, the prepared Au NPs/rGO nanohybrid offers the advantages in large surface area and conductivity as carrier, and UIO-66-NH2 provided an ideal platform to accommodate SAb and a large number of Tb molecules as signal amplifier. In the existence of SCCA, the current peaks of Tb from the formed STEM structure increase with the increase of SCCA level. After optimizing the related control factors, a wide linear range (0.01 pg ml−1 and 15.0 ng ml−1) and very low detection limit (0.003 pg ml−1) of SCCA was achieved, it’s thus expected the designed STEM strategy has important applications for the detection of SCCA.

Fabrication of cervical squamous cell carcinoma antigen immunosensor using graphene-polymer composites

An ultrasensitive electrochemical immunosensor was developed for detection of the cervical squamous cell carcinoma antigen (SCCA) biomarker using graphene-chitosan nanocomposites. Graphene oxide (GO) synthesized by a modified Hummer’s method was functionalized with chitosan biopolymer (CS) to produce CS-GO nanocomposites. Characterization by SEM, FTIR, Raman, XPS confirmed successful grafting of CS onto GO by electrostatic interactions. The CS-GO composite exhibited improved conductivity and biocompatibility. After optimizing the GO:CS ratio to 1:1, the nanocomposite was deposited on glassy carbon electrodes (GCE). Anti-SCCA antibodies were then immobilized covalently using pyrenebutyric acid crosslinker. The immunosensor fabrication was analyzed by EIS, CV, and DPV electrochemical techniques. The conditions including CS-GO ratio, antibody concentration, incubation time, pH, and voltage parameters were systematically optimized using orthogonal experimental design. Under optimal conditions, the immunosensor showed a linear detection range from 1 pg/mL to 100 ng/mL with a sensitivity of 196 μA/(ng/mL/cm2). The low limit of detection of 1 pg/mL was attributed to the high surface area and conductivity of the CS-GO transducer. Analysis of human serum samples spiked with SCCA demonstrated the reliability of the immunosensor for clinical applications. The graphene-nanocomposite electrochemical biosensing platform provides a rapid, low-cost, and ultrasensitive alternative to ELISA for SCCA detection in cervical cancer diagnostics.

High Sensitive and Specific Detection of SCCA via Halloysite Nanotube Modified Terahertz Metasurface Sensor

Squamous cell carcinoma antigen (SCCA) level is an auxiliary indicator for lung cancer diagnosis and predictive monitoring, and its standard reference value is less than 1.5 ng/mL. Therefore, achieving high sensitivity and specific detection of the SCCA is a challenge. In this work, we designed a double split-ring-resonator (SRR) terahertz (THz) metasurface sensor. Simulation results show that the sensitivity of the sensor can reach 103 GHz/RIU (refractive index unit). After the sensor is modified with different concentrations of halloysite nanotubes (HNTs), the resonant frequency of the sensor exhibits different linear responses to different concentrations of SCCA. The optimum concentration of HNTs to enhance the detection performance of the sensor was obtained as 10 mg/mL. The linear range of SCCA concentration of the HNT modified sensor was 1 pg/mL to 100 ng/mL. On this basis, we modified anti-SCCA on the sensor, and other biomarkers of carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), CA125, and CA199 were used as comparisons. The results indicated that the sensor modified with HNTs showed a more remarkable frequency shift for the SCCA, which verified that the sensor had good specificity for the SCCA. Therefore, this sensor can be used for highly sensitive and specific detection of the SCCA.

Bimetallic PtFe alloyed nanoparticles decorated on 3D hollow N-doped carbon nanoflowers as efficient electrochemical biosensing interfaces for ultrasensitive detection of SCCA

Recently, cervical cancer seriously threatens women’s health and life, where squamous cell carcinoma antigen (SCCA) is a representative biomarker widely applied for the early diagnosis and therapy. Herein, bimetallic PtFe alloyed nanoparticles were efficiently decorated on three-dimensional hollow N-doped carbon nanoflowers (PtFe/H-NCFs) by a simple pyrolysis strategy. We strictly investigated the influences of the hollow nanoflower-like structure, N-doping and highly active PtFe nanoalloys on the detection signals from Fe(CN) 6 3– oxidation, coupled with their effects on the loading of the SCCA antibody. Consequently, a high-performance label-free PtFe/H-NCFs-based biosensor was established for ultrasensitive analysis of SCCA, with a wider linear range of 0.01 pg mL –1 -10 ng mL –1 and a lower limit of detection (0.003 pg mL –1 , S/N = 3). The developed sensor holds potential applications for monitoring biomarkers in early diagnosis and clinic therapy. • PtFe/H-NCFs with large surface area were prepared by a one-pot pyrolysis strategy. • PtFe nanoparticles were well decorated on the 3D H-NCFs, showing high electrocatalytic activity. • The prepared immunosensor showed highly improved analytical performance for detecting SCCA.

A SERS microfluidic chip for ultrasensitive and simultaneous detection of SCCA and CYFRA21-1 in serum based on Au nanobowl arrays and hybridization chain reaction

In this work, Au nanobowl (AuNB) arrays and the hybridization chain reaction (HCR) were utilized to develop a surface-enhanced Raman scattering (SERS) microfluidic chip for the ultrasensitive and simultaneous detection of squamous cell carcinoma antigen (SCCA) and cytokeratin 19 fragment antigen 21–1 (CYFRA21–1) in the serum of cervical cancer patients. Antibody-oligonucleotide conjugates were adopted as triggers, which initiated HCR by the hybridization between hairpin DNAs that were modified on Raman reporters-labeled Ag nanocubes, forming nicked double-stranded DNAs on AuNB arrays and leading to SERS signal amplification. Good linear response in the range of 10-12 – 10-6 g/mL, with an ultralow limit of detection for SCCA (0.08 pg/mL) and CYFRA21–1 (0.13 pg/mL), was achieved. Furthermore, the experiments demonstrated that the chip was feasible, time-efficient, and selective. The proposed chip was successfully applied to detect SCCA and CYFRA21–1 in clinical samples, and the results were consistent with those of enzyme-linked immunosorbent assay. Since most protein biomarkers in serum lack the corresponding aptamers, this method, which establishes antibody-oligonucleotide conjugates to trigger HCR, provides a general signal amplification technology for detecting protein biomarkers and exhibits good potential in clinical applications.

Ultrasensitive sandwich-typed electrochemical immunoassay for detection of squamous cell carcinoma antigen based on highly branched PtCo nanocrystals and dendritic mesoporous SiO2@AuPt nanoparticles.

Squamous cell carcinoma antigen (SCCA) is one of the common squamous cell carcinomas (SCC) in women, which usually works as a tumor biomarker for cervical cancer in diagnostic applications. Herein, bimetallic PtCo highly branched nanocrystals (PtCo BNCs) acted as electrode substrates to construct sandwich-typed electrochemical immunosensor for ultrasensitive detection of SCCA, by using dendritic mesoporous SiO2@AuPt nanoparticles (DM-SiO2@AuPt NPs) to adsorb electroactive thionine (Thi) as a signal label. The PtCo BNCs enlarged the loading of the primary antibody (Ab1), showing effective improvement in conductivity and sensitivity. The DM-SiO2 had abundant pores to incorporate more Thi, on which the decorated AuPt NPs created a great number of active sites to immobilize the secondary antibodies (Ab2), thereby obviously amplifying the detection signals. The prepared sensor exhibited a broader linear range (0.001-120ngmL-1) and a lower detection limit (0.33pgmL-1, S/N = 3), combined with high reproducibility, a low relative standard deviation (below 2.5%) and acceptable recovery (from 98.5 to 110.0%) even in diluted human serum samples. This research provides a substantial platform for clinical diagnosis of SCCA in practice.

Clinical application of serum tumor abnormal protein combined with tumor markers in lung cancer patients.

Aim: To explore the clinical application of tumor abnormal protein (TAP) combined with tumor markers in the diagnosis of lung cancer. Methods: Samples from 248 lung cancer patients and 59 patients with benign lung diseases were tested for TAP and tumor markers pro-gastrin-releasing peptide, carcinoembryonic antigen, NSE, CYFRA 21-1 and CA72-4. Results: The sensitivity of TAP and CYFRA 21-1 in the lung cancer group was significantly higher than that of the other indexes. TAP combined with NSE and CYFRA 21-1 or combined with NSE, CYFRA 21-1 and squamous cell carcinoma antigen detection could reduce detection indicators under the premise it does not reduce the sensitivity and accuracy of lung cancer diagnosis, and at the same time could improve the specificity, positive predictive value and positive likelihood ratio of detection. Conclusion: TAP detection represents a promising diagnostic tool. It is also suggested that combination with established tumor markers and comprehensive judgment could improve the accuracy of lung cancer auxiliary diagnosis.

A sandwich SERS immunoassay platform based on a single-layer Au-Ag nanobox array substrate for simultaneous detection of SCCA and survivin in serum of patients with cervical lesions.

The evaluation of tumor biomarkers in blood specimens is vital for patients with cervical lesions. Herein, an ultrasensitive surface enhanced Raman scattering (SERS) platform was proposed for simultaneous detection of cervical-lesion-related serum biomarkers. Raman reporter labeled Au–Ag nanoshells (Au–AgNSs) acted as SERS tags and an Au–Ag nanobox (Au–AgNB) array substrate prepared by the oil–water interface self-assembly method was used as a capture substrate. This single-layer Au–AgNB array substrate was proved to have exceptional uniformity by atomic force microscopy and SERS mapping. Numerous “hot spots” and specific adsorption surfaces offered by the Au–AgNB array substrate were confirmed by the finite difference time domain method, which could generate a SERS signal in electromagnetic enhancement. Binding of antigens between antibodies on Au–AgNSs and the Au–AgNB array substrate led to the formation of a sandwich-structure by the two metal nanostructures. Consequently, an ultralow detection limit of 6 pg mL−1 for squamous cell carcinoma antigen (SCCA) and 5 pg mL−1 for survivin in a wide linear logarithmic range of 10 pg mL−1 to 10 μg mL−1 was acquired. High selectivity and reproducibility with relative standard deviations of 7.701% and 6.943% were detected. Furthermore, the simultaneous detection of the two biomarkers in practical specimens was conducted, and the results were consistent with those of the enzyme-linked immunosorbent assay. This platform exhibited good robustness in the rapid and sensitive detection of SCCA and survivin, which could be a promising tool in early clinical diagnosis for different grades of cervical lesions.

Combined Detection of ACTN4 and SCC-Ag is a Promising Serological Biomarker for Cervical Intraepithelial Neoplasia 3 or Worse: A Case-Control Study.

PurposeCervical cancer (CC) is a common malignancy in women. Squamous cell carcinoma antigen (SCC-Ag) and cancer antigen (CA)-125 are widely used to help diagnose CC, but novel tumour markers with superior sensitivity and specificity are needed. α-Actinin 4(ACTN4) is overexpressed in CC, though its diagnostic value for CC is unclear. This study examined the diagnostic value of ACTN4 and SCC-Ag as biomarkers for cervical intraepithelial neoplasia (CIN) 3 or worse.MethodsWomen screened for CC at Fujian Medical University Union Hospital were recruited from 2017.1 to 2018.5. Cervical tissues and blood were collected at the same time. Patients pathologically diagnosed as CIN3+ or NILM/CIN1/CIN2 were classified into the case and control groups, respectively. ACTN4 mRNA and protein levels were detected through quantitative PCR and immunohistochemistry, respectively, and ACTN4 and SCC-Ag concentrations were analysed by ELISA. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood rate (PLR), negative likelihood rate (NLR), and Youden index (YI) of ACTN4 and SCC-Ag were evaluated. The optimum cut-off points for ACTN4 and SCC-Ag were determined by receiver operating characteristic (ROC) curve analysis, and accuracy was evaluated by the area under the ROC curve.ResultsIn total, 105 patients were classified as CIN3+ cases and 106 as controls. The median ACTN4 levels in case and control tissues were 10.6 and 4.15, respectively. The ACTN4 and SCC-Ag concentrations were significantly higher in cases than controls (PACTN4=0.0007; PSCC-Ag=0.0067). The sensitivity, specificity, PPV, NPV, PLR, NLR and YI of ACTN4 were 68.6%, 76.3%, 76.3%, 72.5%, 2.89, 0.41 and 44.9, respectively; SCC-Ag had a similar diagnostic value (P>0.05), and ACTN4 combined with SCC-Ag had a superior diagnostic value (75.6%, 87.5%, 88.6%, 73.7%, 6.05, 0.28, and 63.1, respectively).ConclusionCombined ACTN4 and SCC-Ag detection is a promising serological biomarker for patients with CIN3 or worse.

A sensitive electrochemiluminescence biosensor based on metal-organic framework and imprinted polymer for squamous cell carcinoma antigen detection

An electropolymerized dopamine molecularly imprinted polymer (MIP) electrochemiluminescence (ECL) biosensor was constructed to detect squamous cell carcinoma antigen (SCCA). Besides having a large surface area, which allows the loading of more ZnSe quantum dots (ZnSeQDs), Fe(III)-MIL-88B-NH2 metal organic framework (MOF) is an efficient co-reaction accelerator that facilitates the transition of S2O82− into SO4−. As a result, the signal probe of Fe(III)-MIL-88B-NH2@ZnSeQDs/Ab has a strong ECL emission, which allowed the development of a three-way signal amplification strategy for ZnSeQDs emission. The electropolymerized dopamine MIP was found to improve the selectivity in the detection of SCCA. Under optimized conditions, the biosensor displayed a wide linear range from 0.0001 to 100 ng mL-1 with a detection limit of 31 fg mL-1. The prepared biosensor showed several advantages, including good specificity, outstanding selectivity and excellent stability. The proposed method can be used for the rapid and sensitive detection of SCCA in human serum and has promise for clinical application.

Label-Free Amperometric Immunosensor Based on Au@Pt DNPs/MoSe2@MoS2 with Multiple Signal Amplification Capabilities for Squamous Cell Carcinoma Antigen Detection

Herein, urchin-like gold@platinum dendritic nanoparticles supported on molybdenum selenide@molybdenum disulfide (Au@Pt DNPs/MoSe2@MoS2) nanocomposite with multiple signal amplification capabilities was successfully synthesized as the matrix platform of label-free amperometric immunosensor for the quantitative detection of squamous cell carcinoma antigen (SCCA). Au@Pt DNPs/MoSe2@MoS2 consists of Au@Pt DNPs with splendid biocompatibility as well as catalysis and MoSe2@MoS2 with reformative peroxidase activity, which owned enhanced electrocatalysis toward hydrogen peroxide reduction and steady bioconjugation for bioprotein immobilization. Additionally, Au@Pt DNPs/MoSe2@MoS2 possessed satisfactory conductivity to accelerate electron transfer at the electrode interface. With the help of Au@Pt DNPs/MoSe2@MoS2, the immunosensor procured a good linear extent of SCCA detection between 100 fg ml−1 and 100 ng ml−1, reached a lower detection limit than previous reports. Moreover, the immunosensor with good stability and reproducibility achieved the specific detection of SCCA in the mixture containing interferents as well as in the real human serum sample, which testified to the proposed amperometric immunosensor was reliable in clinical detection of tumor biomarkers.

Facile fabrication of visible light photoelectrochemical immunosensor for SCCA detection based on BiOBr/Bi2S3 heterostructures via self-sacrificial synthesis method

A novel visible light photoelectrochemical immunosensor based on BiOBr/Bi2S3 heterostructures was fabricated to detect squamous cell carcinoma antigen (SCCA). Bi2S3 nanoparticles formed on the BiOBr microflowers by the self-sacrificial synthesis method based on the facile reaction between BiOBr and S2- ions. The BiOBr/Bi2S3 composites exhibited excellent visible light photoelectrochemical activity, when ascorbic acid (AA) was employed as a perfect electron donor. The photocurrent intensity of BiOBr/Bi2S3 modified ITO electrode arrived at around 20 µA, which was approximately 30 times than that of pure BiOBr. Dopamine formed easily polydopamine film via self-polymerization on the surface of BiOBr/Bi2S3 composites to immobilize SCCA antibody. Under the optimal condition, this photoelectrochemical immunosensor realized the ultrasensitive determination of SCCA. With the logarithm of SCCA concentration in the range of 0.001–75 ng mL−1, the specific binding between SCCA and antibody led to the linearly decrease of photocurrent signal with a low detection limit of 0.3 pg mL−1 (S/N = 3). This facilely constructed photoelectrochemical immunosensor maybe have promising practical application in photocatalysis, analytical detection and biosensor, etc.

Interesting optical variations of the etching of Au Nanobipyramid@Ag Nanorods and its application as a colorful chromogenic substrate for immunoassays

Common colorimetric immunoassays only show monochromatic intensity variations, and the absorbance intensity is utilized for the quantitative detection of the analytes. Herein, we demonstrate for the first time that Au Nanobipyramid@Ag Nanorods (Au NBP@Ag) is an ideal multicolor chromogenic substrate for immunoassays which combines the absorbance intensity with the Localized Surface Plasmon Resonance (LSPR) peak shifts are utilized for quantitative detection of the analytes, and vivid color variations are used for semi-quantitative detection. Our investigation reveals that unlike the single metallic nanoparticles such as gold nanorods which show one-way LSPR peak shifts, Au NBP@Ag Nanorods shows an interesting multi-way peak shifts: the LSPR peak would initially blue shift, and then red shift, finally blue shift again during the etching process. As a result, a series of vivid colors can be observed. The results indicate that the correlation linear range for the detection of Squamous cell carcinoma antigen (SCCA) was 2.5–105 ng/mL. Although only the detection of SCCA is demonstrated in this work, this method is easy to expand to detect other biomarkers since our method is based on conventional immunoassay strategy.

Serum and bile squamous cell carcinoma antigen detection: A new prognostic marker in patients with perihilar cholangiocarcinoma

Serum and bile squamous cell carcinoma antigen detection: A new prognostic marker in patients with perihilar cholangiocarcinoma

Ultrasensitive electrochemical immunosensor for quantitative detection of SCCA using Co3O4@CeO2-Au@Pt nanocomposite as enzyme-mimetic labels

Recently early diagnosis of squamous cell carcinoma antigen (SCCA) as a tumor maker of various cancers has increasingly attracted a lot of attention with heightening of incidence rate of cancer. The SCCA with low concentration in human serum should be diluted before detecting. Thus, an immunoassay with high sensitivity is significant for early detecting SCCA. Therefore, a nonenzymatic sandwich-type electrochemical immunosensor herein was conducted to quantitative detection of squamous cell carcinoma antigen (SCCA). The amino functionalized cobaltosic oxide @ ceric dioxide nanocubes with core-shell morphology were prepared to combine sea-urchin like gold @ platinum nanoparticles (Co3O4@CeO2-Au@Pt), and used as labels to conjugate with secondary antibodies for signal amplification. Due to the synergetic effect, excellent electrochemical property and superior auxiliary catalytic activity of Co3O4@CeO2-Au@Pt, high electrocatalytic current responses toward the reduction of hydrogen peroxide (H2O2) were achieved. Besides, the electrodeposited gold nanoparticles (D-Au NPs) which were modified on glassy carbon electrodes (GCE) were used as antibodies carriers and sensing platforms. With the well cooperation of Co3O4@CeO2-Au@Pt and D-Au NPs, a broad linear range from 100fg/mL to 80ng/mL with a low detection limit of 33 fg/mL for detecting SCCA was achieved. In addition, the immunosensor displayed with good reproducibility, high selectivity and stability. The results are satisfactory when the proposed method has been applied to analyze human serum samples, indicating that the potential application is promising in clinical monitoring of tumor markers.

Ultrasensitive and visual detection of squamous cell carcinoma antigen based on a silver-enhanced sandwich immunoassay using AuNPs@g-C3N4 nanocomposites

Based on gold label silver stain (GLSS) method, a sandwich-type immunoassay for visual, ultrasensitive and specific detection of squamous cell carcinoma antigen (SCCA) was constructed using gold nanoparticles@graphite- like carbon nitride (AuNPs@g-C3N4). In this assay, the capture SCCA antibody (Ab1) was immobilized on the silanized slides via the Schiff’s base links, and the AuNPs@g-C3N4 nanocomposite labeled by the detection SCCA antibody (Ab2) acted as the signal probe. The detection mechanism was as follows: Ab1 was immobilized onto the silanized slides in order to catch the target antigen SCCA, and then allowed the immobilization of the signal probe (Ab2) via the interaction between antigen and antibody. Compared with conventional GLSS method in which AuNPs are directly immobilized on Ab2, much more AuNPs corresponded to the antigen SCCA through AuNPs@g-C3N4 because g-C3N4 possessed larger surface area and loaded much more AuNPs than Ab2. Therefore, more AuNPs were exposed to silver ions during staining, more silver ions were reduced, and the sensitivity improved 1000-fold. The average grey values were linearly related to the logarithm of SCCA concentration from 0.001ng/mL to 100ng/mL, with high specificity, good reproducibility and long-term stability. Results suggested that the proposed sandwich immunoassay based on GLSS method is a simple, sensitive, selective, and visual tool for the detection of SCCA.

Ultrasensitive electrochemical immunosensor for SCCA detection based on ternary Pt/PdCu nanocube anchored on three-dimensional graphene framework for signal amplification

In this study, a novel and ultrasensitive sandwich-type electrochemical immunosensor was designed for the quantitative detection of squamous cell carcinoma antigen (SCCA) based on the β-cyclodextrin functionalized graphene nanosheet (CD-GN) and the ternary hollow Pt/PdCu nanocube anchored on three-dimensional graphene framework (Pt/PdCu-3DGF). CD-GN exhibited high specific surface area and good dispersibility and stability in water, which were beneficial to fix captured antibodies (Ab1) through the supramolecular host-guest interaction between CD and Ab1. The abundant oxygen-containing functional groups on 3DGF provided binding sites for anchoring noble metal nanoparticles. Pt/PdCu-3DGF could capture detected antibodies via the interaction of Pd-NH2 and Pt-NH2. Furthermore, the ternary metal nanoparticles exhibited high electrocatalytic activity toward the reduction of hydrogen peroxide. Under optimal conditions, the fabricated immunosensor showed a sensitive response to SCCA with two linear ranges. The linear ranges are 0.0001–1ng/mL and 1–30ng/mL with a detection limit of 25fg/mL. Additionally, the proposed immunosensor showed good reproducibility and stability.

Multifunctional reduced graphene oxide trigged chemiluminescence resonance energy transfer: Novel signal amplification strategy for photoelectrochemical immunoassay of squamous cell carcinoma antigen

Herein, a photoelectrochemical (PEC) immunoassay is constructed for squamous cell carcinoma antigen (SCCA) detection using zinc oxide nanoflower-bismuth sulfide (Bi2S3) composites as photoactive materials and reduced graphene oxide (rGO) as signal labels. Horseradish peroxidase is used to block sites against nonspecific binding, and then participated in luminol-based chemiluminescence (CL) system. The induced CL emission is acted as an inner light source to excite photoactive materials, simplifying the instrument. A novel signal amplification strategy is stem from rGO because of the rGO acts as an energy acceptor, while luminol serves as a donor to rGO, triggering the CL resonance energy transfer phenomenon between luminol and rGO. Thus, the efficient CL emission to photoactive materials decreases. Furthermore, the signal amplification caused by rGO labeled signal antibodies is related to photogenerated electron–hole pairs: perfect matching of energy levels between rGO and Bi2S3 makes rGO a sink to capture photogenerated electrons from Bi2S3; the increased steric hindrance hinders the electron donor to the surface of Bi2S3 for reaction with the photogenerated holes. On the basis of the novel signal amplification strategy, the proposed immunosensor exhibits excellent analytical performance for PEC detection of SCCA, ranging from 0.8pgmL−1 to 80ngmL−1 with a low detection limit of 0.21pgmL−1. Meanwhile, the designed signal amplification strategy provides a general format for future development of PEC assays.