Prostate Specific Antigen In Human Serum Research Articles

Ultrasensitive detection of PSA in human serum using Label-Free electrochemical biosensor with magnetically induced Self-Assembly based on α-Fe2O3/Fe3O4@Au nanocomposites

To achieve the goals of early diagnosis, screening, and precision medicine for prostate cancer, this research designed a label-free electrochemical biosensor by combining magnetic probes (PSAA/α-Fe2O3/Fe3O4@Au) with magnetically induced self-assembly (MISA) technology to explore the application of prostate-specific antigen (PSA) in precise detection. Magnetic α-Fe2O3/Fe3O4 nanoparticles (NPs) were constructed using a hydrothermal-calcination reduction method. Subsequently, α-Fe2O3/Fe3O4@Au nanocomposites were prepared by reducing HAuCl4 with NaBH4 at a low temperature. The self-assembly method was adopted in two steps: firstly, the sulfhydryl-modified PSA aptamer is immobilized onto the material surface using Au–S bonds; secondly, the magnetic NPs and magnetic glassy carbon electrode (MGCE) undergo self-assembly. The biosensor showed good linear response in the range of 100 fg/mL to 100 ng/mL, with a detection limit of 0.78 pg/mL (S/N = 3) under optimal conditions. Repeatability, stability, selectivity, reproducibility, and the capability to analyze real samples were also investigated. With its cost-effectiveness, operational simplicity, and speed of analysis, the biosensing system platform holds great potential as a valuable tool in clinical PSA detection for point-of-care testing (POCT).

A label-free and ratiometric fluorescent immunosensor by integrating CRISPR/Cas 12a and 3D DNA nanomachine

Sensitive, selective, especially label-free detection of disease relevant protein biomarkers is highly valuable for clinical diagnosis and disease process monitoring but remains a challenge. Herein, with prostate specific antigen (PSA) as a model target, we have designed a label-free ratiometric fluorescent immunosensor based on three-dimensional (3D) DNA walker and the powerful clustered regularly interspaced short palindromic repeat (CRISPR)/Cas system, with poly(thymine) templated Cu nanoclusters and DAPI as signals. The aptamer-linked activator DNA was designed to convert target recognition event into activate deoxyribonuclease activity of CRISPR/Cas12a system and further cleave oligonucleotides. The cleavage behavior leads to the quenching of copper nanoclusters and stagnation of the cascade amplification progress of 3D DNA nanomachine. The DNA machine is constructed from primer DNA and silica nanospheres loaded by double-stranded DNA (dsDNA) with prominent 3′ end, and movement of the primer DNA is powered by exonuclease (Exo) III via a burnt-bridge mechanism. Without primer DNA, the dyes (DAPI) were embedded in the complementary DNA and emit strong fluorescence. The practical applicability of the biosensor was demonstrated by assay of PSA in human serum with satisfactory result. In addition, this completely label-free method, reduced consumption of antibody, greatly simplify the procedures and saving cost.

Aggregation-induced electrochemiluminescence resonance energy transfer with dual quenchers for the sensitive detection of prostate-specific antigen

Here, gold nanoclusters (AuNCs) were wrapped with 6-aza-2-thiothymine (ATT). The aggregation of AuNCs protected by ATT induced the electrochemiluminescence (ECL) enhancement of AuNCs. A new dual-quenching ECL immunosensor based on a solid-state ATT−AuNCs (SS−ATT−AuNCs) luminophore and aggregation-induced emission (AIE) was designed for the sensitive determination of prostate-specific antigen (PSA). The synthesized CeO2-PEI@Ag composite could be used as the carrier to immobilize secondary antibody (Ab2) and also to improve the efficiency of the ECL sensing platform based on resonance energy transfer between SS−ATT−AuNCs and CeO2-PEI@Ag. Under the optimal conditions, the prepared dual-quenching aggregation-induced electrochemiluminescence resonance energy transfer (AIECL-RET) immunosensor showed a linear range from 1 × 10−5 ng/mL to 200 ng/mL and a detection limit of 2.2 fg/mL (S/N = 3). The prepared AIECL-RET sensor was successfully applied to detect PSA in human serum with high stability and good selectivity. This study enriches ECL research strategies, provides a feasible method for basic clinical testing, and shows the potential applications of ECL sensors in clinical bioassays.

Peroxymonosulfate Activation on Synergistically Enhanced Single-Atom Co/Co@C for Boosted Chemiluminescence of Tris(bipyridine) Ruthenium(II) Derivative.

Tris(bipyridine) ruthenium(II)-based luminophores have been well developed in the area of electrochemiluminescence, while their applications in chemiluminescence (CL) are rarely studied due to the poor luminous efficiency and complicated CL reaction. Herein, a novel tris(bipyridine) ruthenium(II)-based ternary CL system is proposed by introducing cobalt single atoms integrated with graphene-encapsulated cobalt nanoparticles (Co SAs/Co@C) and peroxymonosulfate (PMS) as advanced coreaction accelerator and promising coreactant, respectively. On the basis of the experimental results and density functional theory calculations, it is concluded that Co@C can synergistically modulate the adsorption behavior of PMS on Co SAs and then efficiently activate PMS to produce massive singlet oxygen for remarkable CL emission. Under the optimum conditions, the as-prepared CL biosensor exhibits a good linear range, excellent sensitivity, and selectivity, holding great potential for the practical detection of prostate-specific antigen in human serum.

Ultrasensitive Immunosensor for Prostate-Specific Antigen Based on Enhanced Electrochemiluminescence by Vertically Ordered Mesoporous Silica-Nanochannel Film.

Ultrasensitive and specific detection of prostate-specific antigen (PSA) in complex biological samples is crucial for early diagnosis and treatment of prostate-related diseases. Immunoassay with a simple sensing interface and ultrahigh sensitivity is highly desirable. Herein, a novel electroluminescence (ECL) immunosensing platform is demonstrated based on the equipment of vertically ordered mesoporous silica-nanochannel films (VMSFs) with PSA antibody, which is able to realize ultrasensitive detection of PSA in human serum. Through the electrochemically assisted self-assembly (EASA) method, the VMSF is easily grown on an indium tin oxide (ITO) electrode in a few seconds. Owing to a large surface area and the negatively charged surface, VMSF nanochannels display strong electrostatic attraction to the positively charged ECL luminophores (tris(2,2-bipyridyl) dichlororuthenium (II), (Ru(bpy)3 2+), leading to two orders-of-magnitude enhancement of ECL emission compared with that of the bare ITO electrode. The outer surface of the VMSF is functionalized with reactive epoxy groups, which further allows covalent attachment of PSA antibody (Ab) on the entry of nanochannels. As the combination of PSA with Ab decreases the ECL signal by hindering the mass transfer of ECL luminophores and coreactant, the developed immunosensor can achieve ultrasensitive detection of PSA ranging from 1 pg ml−1 to 100 ng ml−1 with a limit of detection (LOD) of 0.1 pg ml−1. Considering the antifouling ability of the VMSF, sensitive detection of PSA in human serum is also realized. The proposed nanochannel-based immunosensor may open up a new way for the facile development of the universal immunosensing platform for rapid and ultrasensitive detection of disease markers.

Electrochemical immunosensor for ultra-sensitive detection of attomolar prostate specific antigen with sulfur-doped graphene quantum dot@gold nanostar as the probe

A novel sulfur-doped graphene quantum dot (S-GQD) decorated 3-dimensional gold nanostar (AuNS/S-GQD) nanocomposite has been developed as the actively electrochemical immunosensing material for ultra-sensitive and selective detection of attomolar prostate specific antigen (PSA) in phosphate buffer saline (PBS) and human serum. The S-GQDs were hydrothermally prepared at 180 °C for 10 h, and then AuNS/S-GQDs were fabricated by reducing Au precursor to AuNS in the presence of S-GQDs at room temperature. The electronic microscopic results indicate that 2 – 8 nm S-GQDs are homogenously deposited onto the 35 – 60 nm AuNS surface. The AuNS provides an excellent electric conductivity for electrochemical performance, while S-GQD serves as a sensing probe to bind prostate specific antibody (Ab) via amide bonding. After deposition of AuNS/S-GQDs onto screen-printed electrode (Es), the Es||AuNS/S-GQD/Ab immunosensor provides a stable, ultra-sensitive, and highly selective platform for PSA detection. The wide detection ranges of 10 fg mL−1 – 50 ng mL−1 and 100 fg mL−1 – 35 ng mL−1 with low limits of detection (LOD) of 0.29 (9.7 aM) and 26 fg mL−1 in PBS and neat human serum, respectively, are obtained. Moreover, the Es||AuNS/S-GQD/Ab immunosensor can effectively detect PSA in human serum with recovery of 97 – 107%. The high selectivity toward PSA detection over the other 8 interferences and low cytotoxic effect of Es||AuNS/S-GQD/Ab immunosensor are also observed. These excellent results demonstrate the potential of using AuNS/S-GQD nanocomposite as an electrochemically biosensing probe to effectively detect PSA and other cancer markers in human serum for clinically early diagnosis.

A Complete Analytical Model for MOS-HEMT Biosensors: Capturing the Effect of Stern Layer and Charge Screening on Sensor Performance

This letter presents analytical and technology computer aided design models for analyzing the performance of biohigh-electron-mobility transistor (HEMT) sensors. Unlike existing models for these sensors in the literature, where the biolayer is modeled as semiconductor or insulator layer with analyte-induced interface charge (i.e., surface potential), the model presented in this letter provides a better design insights by taking into consideration charge screening effect and impact of electric double layer (Stern layer) on device performance. The simulation case study is focused on prostate cancer detection using prostate-specific antigen (PSA) present in human serum as the target biomarker. Application specific validation of the model has been presented through demonstration of a MOS-HEMT PSA sensor design with sensitivity large enough to detect clinically relevant concentration of PSA in human serum (1ng/ml-4ng/ml).

Gold Nanomaterial Hybrid on PEGylated Metal Oxide Interdigitated Mini-electrode Surface to Diagnose Prostate Cancer

Prostate cancer is a leading health burden, the third most common cancer in a man. High accuracy detection and screening methods with a suitable biomarker can significantly reduce the risk of mortality. Prostate specific antigen (PSA) is the efficient and acceptable biomarker due to its level of increment in the biological fluid with the prostate cancer patient. This research was focused to establish a sensitive method of PSA detection by using gold nanoparticle (GNP) conjugated PSA specific aptamer on interdigitated mini-electrode. GNP allowed to capture higher number of aptamers on the surface and enhanced the interaction of PSA. This good detection method can determine PSA at 45[Formula: see text]aM with the sensitivity of 30[Formula: see text]aM. A linear range was noticed from 60 until 2000 aM on the regression curve at [Formula: see text]; [Formula: see text]. Moreover, spiking PSA in human serum enhances the current response with increasing PSA concentrations. This method of determination helps to quantify the PSA level and diagnose the prostate cancer at different stages.

ZnO Nanorod FET Biosensors With Enhanced Sensing Performance: Design Issues for Rational Geometry Selection

ZnO nanorod field effect transistor (FET) biosensors enable ultrasensitive, rapid and label free detection of biomolecules. However, the fabrication of these nanorods without any design guideline results in poor signal to noise ratio, limiting their commercial deployment. The various forces operating within the spacing of the nanorods may prevent complete penetration of the liquid for large aspect ratios and hence mere enhancement of the geometric surface area may not yield the optimum output which indicates the intricacies involved in the design of such sensors. The present work consistently models the analyte and the device regions of the sensor by transforming the understanding of the transduction mechanism of biomolecule capture in nanowire FETs into nanorod FET structure and integrating the spacing dependent liquid penetration depth along with the various temporal fluctuations of the sensor to enhance the signal to noise ratio ( SNR ) and lower the molecule detection limit(MDL). Simulation results, verified experimentally for prostate specific antigen (PSA) shows that the optimal geometry does not correspond to the maximum surface area. Instead it is dependent on the developed surface potentials after receptor immobilization and ligand capture which vary non-monotonically with nanorod radius due to nonlinear dependence of buffer penetration for high aspect ratios. This approach has significantly increased the SNR leading to reliable quantification of PSA in human serum with MDL reduced by almost three orders of magnitude in comparison to recent reports. In summary, this work brings the ZnO nanorod sensors a step closer towards practical application for early diagnosis.

An ultrasensitive label-free electrochemical immunosensor based on 3D porous chitosan–graphene–ionic liquid–ferrocene nanocomposite cryogel decorated with gold nanoparticles for prostate-specific antigen

A highly sensitive and selective label-free electrochemical immunosensor was successfully fabricated for measuring prostate-specific antigen (PSA). A composite of chitosan, graphene, ionic liquid and ferrocene (CS-GR–IL–Fc) was drop casted onto a screen-printed carbon electrode (SPCE) and frozen to create a layer of 3D porous cryogel (CS-GR-IL-Fc cry) which was decorated with gold nanoparticles (AuNPs). The biocompatibility and porosity of the cryogel increased the surface area available for AuNPs loading via amino groups and the population of anti-PSA, immobilized on the AuNPs via chemisorption, could be increased. The CS-GR-IL-Fc cry displayed excellent conductivity, enhancing electron transfer and amplifying the current signal. Differential pulse voltammetry was employed to determine PSA by measuring the reduction in the Fc oxidation peak current in response to the formation of PSA/anti-PSA immunocomplex. Under the optimized incubation time and electrolyte pH, the developed immunosensor displayed excellent analytical performances, including a wide linear range at concentrations from 1.0 × 10−7 to 1.0 × 10−1 ng mL−1, with a very low limit of detection of 4.8 × 10−8 ng mL−1 and good reproducibility (relative standard deviation of <4.6%, n = 6), stability (90% sensitivity within 20 days), repeatability (12 cycles of binding–rebinding, the sensitivity > 90%) and selectivity. The results obtained from the device for the determination of PSA in human serum were consistent with results from the enzyme-linked immunosorbent assay (P > 0.05), and indicated the promising potential of the proposed immunosensor in clinical diagnosis.

Label-free electrochemical immunosensor for the detection of prostate specific antigen based three-dimensional Au nanoparticles/MoS2-graphene aerogels composite

In the present work, a label-free prostate specific antigen (PSA) electrochemical immunosnesor was constructed based on Au nanoparticles/MoS2-graphene aerogels nanocomposite (AuNPs/MoS2-GAs) as sensing platform. MoS2-GAs composite with porous network structure provided large specific area for the immobilization of AuNPs, which further improved the loading of PSA antibodies. In addition, the AuNPs/MoS2-GAs composite has good conductivity, which could accelerate the electron transport of the electrode interface. Based on these advantages of AuNPs/MoS2-GAs material, the prepared immunosensor exhibited wide linearity in the range of 0.00001–50 ng mL−1 and a low detection limit of 0.003 pg mL−1. The immunosensor also exhibited acceptable stability, good selectivity, and reproducibility. Moreover, when applied to analyze PSA in human serum, the immunosensor obtained good recovervries, indicating the method shows a promising application for early diagnosis of PSA.

Recyclable label-free SERS-based immunoassay of PSA in human serum mediated by enhanced photocatalysis arising from Ag nanoparticles and external magnetic field

In the field of SERS-based immunoassay, the recyclable utilization of noble metal materials is essential for their practical application in clinical medicine. Herein, a kind of novel multifunctional Fe3O4@TiO2@Ag microparticles (MPs) was synthesized through a poly-step reaction, and then their feasibility for recyclable label-free SERS-based immunoassay of prostate specific antigen (PSA) was demonstrated. The photocatalytic efficiency of the Fe3O4@TiO2@Ag MPs was fully adjusted by tuning the thickness of the middle TiO2 shell and the areal density of the outside Ag NPs. Particularly, the Fe3O4 core played a critical role in further improving the photocatalytic activity under external magnetic field. Thereafter, the successfully photocatalytic degradation and recyclable detection of PSA in human serum was confirmed by the change of O 1s, N 1s, and C 1s signals in the XPS characterization and a limit of detection as low as 16.25 pg/mL was realized. Furthermore, the quantitative recyclable detection of PSA in clinical serum samples with prostate cancer was conducted, and the results are basically consistent with those of the traditional chemiluminescent immunoassay, showing small relative deviation less than or equal to 5.7%.

A cost-effective and rapid aptasensor with chemiluminescence detection for the early diagnosis of prostate cancer

A rapid aptasensor capable of early diagnosing prostate cancer was developed using a dual aptamer, which is composed of a prostate specific antigen (PSA) aptamer and hemin aptamer connected by a linker composed of 5 adenines. The dual aptamers immobilized on the surface of paramagnetic beads were able to competitively bind with PSA or hemin in human serum for 20 min at room temperature. After the incubation, the dual aptamers were separated from human serum using a magnetic separator. After the procedure, the mixture of Amplex Red and H2O2 in Tris–HCl (pH 8) was added in a microcentrifuge tube containing the dual aptamers. Resorufin was formed from the reaction of Amplex Red and H2O2 in the presence of horseradish peroxidase (HRP) mimicking DNAzyme formed from the reaction of hemin and the dual aptamer. The concentration of resorufin formed from the reaction was proportional to the concentration of HRP mimicking DNAzyme. Resorufin emitted bright red light with the addition of 1,1′-oxalyldiimidazole (ODI) chemiluminescence reagents such as ODI and H2O2. The brightness of the emission light was proportionally reduced with the increase of PSA in human serum due to the reduction of DNAzyme concentration with the binding of PSA and PSA aptamer linked to hemin aptamer. Using the calibration curve of the new aptasensor, trace levels of PSA in human serum was rapidly quantified for the early diagnosis of prostate cancer. The limit of detection (LOD = 3 s/slope) of the aptasensor was as low as 0.1 ng/ml. The accuracy, precision, and recovery of the aptasensor were studied with statistically acceptable methods.

A surface-enhanced electrochemiluminescence sensor based on Au-SiO2 core-shell nanocomposites doped with Ru(bpy)32+ for the ultrasensitive detection of prostate-specific antigen in human serum.

This study reports a surface-enhanced electrochemiluminescence (SEECL) sensor for the ultrasensitive detection of prostate-specific antigen (PSA) in human serum. First, we prepared the Au-SiO2 core-shell nanocomposites doped with Ru(bpy)32+ (Au@SiO2-Ru) as the ECL signal generation and amplification element of the SEECL sensor. Ru(bpy)32+ could emit ECL under the excitation of an electrochemical reaction, and generate the local surface plasmon resonance (LSPR) electromagnetic field from the gold nanoparticle (AuNP) core. The produced LSPR then effectively enhanced the ECL signals. This sensing strategy was utilized for the detection of PSA, which can be absorbed on the electrode surface by the reaction between PSA and monoclonal antibodies. When polyclonal antibody-modified Au@SiO2-Ru was added, the PSA-double-antibody sandwich structure was formed on the electrode surface and thus, the Au@SiO2-Ru were quantitatively immobilized on the electrode surface. The results show that this kind of SEECL sensor has good selectivity toward PSA. Notably, the minimum detection concentration reached 7 × 10-7 ng mL-1 under the optimum experimental conditions, which is much better than most of the previously reported approaches for the detection of PSA in serum.

Unravelling the Role of Electric and Magnetic Dipoles in Biosensing with Si Nanoresonators.

High refractive index dielectric nanoresonators are attracting much attention due to their ability to control both electric and magnetic components of light. Due to the combination of confined modes with reduced absorption losses, they have recently been proposed as an alternative to nanoplasmonic biosensors. In this context, we study the use of semirandom silicon nanocylinder arrays, fabricated with simple and scalable colloidal lithography for the efficient and reliable detection of biomolecules in biological samples. Interestingly, electric and magnetic dipole resonances are associated with two different transduction mechanisms: extinction decrease and resonance red shift. By contrasting both observables, we identify clear advantages in tracking changes in the extinction magnitude. Our data demonstrate that, despite its simplicity, the proposed platform is able to detect prostate-specific antigen in human serum with limits of detection meeting clinical needs.

MESIA: Magnetic force-assisted electrochemical sandwich immunoassays for quantification of prostate-specific antigen in human serum

We propose a new immunoassay technique, called magnetic-force assisted electrochemical sandwich immunoassay (MESIA), where serum biomarkers can be determined by magnetic actuation and electrochemical detection of gold-coated iron oxide nanoparticles as probes for immunocomplex formation. In MESIA, neither washing buffer nor fluidic parts are necessary, because the formation of immunocomplexes and the removal of unbound probes are controlled by magnetic forces. Electrochemical pretreatment and measurement of the gold-coated magnetic probes allows highly sensitive, precise, and robust system for quantification of target analytes. Using MESIA, the concentration of prostate-specific antigen (PSA) in 10 μl of human serum is determined within 5 min. The limit of detection is 0.085 ng/mL, and the average coefficient of variance is 8.85% for five different PSA concentrations ranging from 0 to 25 ng/mL. This method shows good precision and reproducibility (<10%) and high correlation with cobas e 801 (r = 0.997) for clinical patient samples. We believe this technique to be useful in the development of a point-of-care testing platform for diagnosis and prognosis of various diseases, such as cancer, based on quantification of biomarkers in a drop of blood.

A robust electrochemical immunosensor based on hydroxyl pillar[5]arene@AuNPs@g-C3N4 hybrid nanomaterial for ultrasensitive detection of prostate specific antigen

Prostate specific antigen (PSA) is the most significant biomarker for the screening of prostate cancer in human serum. However, most methods for the detection of PSA often require major laboratories, precisely analytical instruments and complicated operations. Currently, the design and development of satisfying electrochemical biosensors based on biomimetic materials (e.g. synthetic receptors) and nanotechnology is highly desired. Thus, we focused on the combination of molecular recognition and versatile nanomaterials in electrochemical devices for advancing their analytical performance and robustness. Herein, by using the present prepared multifunctional hydroxyl pillar[5]arene@gold nanoparticles@graphitic carbon nitride (HP5@AuNPs@g–C3N4) hybrid nanomaterial as robust biomimetic element, a high-performance electrochemical immunosensor for detection of PSA was constructed. The as-prepared immunosensor, with typically competitive advantages of low cost, simple preparation and fast detection, exhibited remarkable robustness, ultra-sensitivity, excellent selectivity and reproducibility. The limit of detection (LOD) and linear range were 0.12 pg mL–1 (S/N = 3) and 0.0005–10.00 ng mL–1, respectively. The satisfying results provide a promising approach for clinical detection of PSA in human serum.

Graphene oxide layer decorated gold nanoparticles based immunosensor for the detection of prostate cancer risk factor

In this work, we report a novel electrochemical immunosensor based on gold nanoparticles deposited on the surface of graphene oxide layers and was used for immobilization of monoclonal anti-PSA antibody via EDC/NHS coupling method to detect prostate-specific antigen (PSA), a valuable biomarker for early detection of prostate cancer. To confirm the functionality of the antibody, we performed immunofluorescence staining using human prostate adenocarcinoma cells, LNCaP. Scanning Electron Microscopy (SEM), cyclic voltammetry, and other electrochemical techniques were used to characterize the resulting electrode surface. Unlike the previous research, this novel immunosensor functions very well with a low detection limit of 0.24 fgmL−1 at signal to noise ratio of 3; furthermore, it exhibits a significantly increased electron transfer and high sensitivity of 5.4 μA fgmL−1 with regression coefficient (R2 = 0.99) toward PSA. The immunosensor was verified for selective and accurate detection of PSA in human serum with recovery of 97.67%. Overall, data suggested that our developed biosensor holds great promise as a useful alternative diagnostic tool for the detection of different cancer biomarkers, in particular PSA present in biological samples.

A novel immunosensing platform for highly sensitive prostate specific antigen detection based on dual-quenching of photocurrent from CdSe sensitized TiO2 electrode by gold nanoparticles decorated polydopamine nanospheres

Herein, a novel photoelectrochemical (PEC) immunosensing platform for highly sensitive detection of prostate specific antigen (PSA) was constructed based on dual-quenching of photocurrent from CdSe sensitized TiO2 electrode by gold nanoparticles decorated dopamine–melanin nanospheres (AuNPs-Dpa-melanin CNSs). In this proposal, CdSe sensitized TiO2 was used as photoelectrochemical matrix and the functional AuNPs-Dpa-melanin CNSs were used as signal quenching element. The dual quenching of the gold nanoparticles decorated Dpa-melanin CNSs to the CdSe sensitized TiO2 was achieved as follows: (i) the strong energy transfer between the CdSe quantum dots (QDs) and Au NPs diminishes the photocurrent signal of CdSe QDs; (ii) the steric hindrance of AuNPs-Dpa-melanin CNSs partly obstructs the diffusion of the electron donor, i.e. ascorbic acid, to the surface of photoelectrode, which make the depleting efficiency of the photogenerated holes decrease, leading to a declined photocurrent intensity. On the basis of the dual quenching effect of AuNPs-Dpa-melanin CNSs, a competitive immunosensing platform for PSA was designed upon the specific binding of anti-PSA to PSA and PSA functionalized AuNPs-Dpa-melanin CNSs conjugates. This proposed immunosensor possesses wide linear range from 1.0×10–11gmL−1 to 1.0×10−7gmL−1 with the detection limit of 2.7pgmL−1. Moreover, the applicability of the present method was demonstrated in the determination of PSA in human serum. The strategy creates new paradigms for PSA and other tumor markers detection and demonstrates high sensitivity, good specificity, and satisfied applicability in complex biological samples.

Ultrasensitive amperometric immunosensor for PSA detection based on Cu2O@CeO2-Au nanocomposites as integrated triple signal amplification strategy

In this work, a novel label-free electrochemical immunosensor was developed for the quantitative detection of prostate specific antigen (PSA). To this end, the amino functionalized cuprous oxide @ ceric dioxide (Cu2O@CeO2-NH2) core-shell nanocomposites were prepared to bond gold nanoparticles (Au NPs) by constructing stable Au-N bond between Au NPs and -NH2. Because the synergetic effect presents in Cu2O@CeO2 core-shell loaded with Au NPs (Cu2O@CeO2-Au), it shows better electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2) than single Cu2O, Au NPs and Cu2O@CeO2. Featured by large specific surface area, good biocompatibility and good electrochemical properties which can greatly improve the electronic transmission rate, Cu2O@CeO2-Au was used as transducing materials to achieve efficiently capture antibodies and triple signal amplification of the proposed immunosensor. Under the optimal conditions, the proposed immunosensor exhibited a wide linear range from 0.1pg/mL to 100ng/mL with a low detection limit of 0.03pg/mL (S/N=3). Furthermore, the proposed label-free immunosensor has been used to determine PSA in human serum with satisfactory results. Meanwhile, it displayed good reproducibility, acceptable selectivity, and long-term stability, which had promising application in bioassay analysis.