Detection Of Prostate Specific Antigen Research Articles

Detection of prostate specific antigen using a magnetic sulfonated reduced graphene oxide/gold nanoparticle aptasensor

Prostate-specific antigen (PSA), is a protein produced by cancerous cells in the prostate gland, and its presence may indicate the likelihood of prostate cancer. For the purpose of detecting PSA, an innovative aptasensor utilizing magnetic sulfonated reduced graphene oxide/gold nanoparticles was developed. This unique nanocomposite has been used for the first time for biosensing of prostate cancer which resulted in significant enhancement of the biosensor’s performance. Unlike previous works, our biosensor incorporates two detection modes: a label-free detection mode in ferrocyanide solution and a labeled mode using methylene blue. Different tests such as FTIR, XRD and TEM were applied to recognize the characterization of the nanoparticles and to make sure of the linkage of particles. To examine the aptasensor at various stages, a range of electroanalytical techniques, such as cyclic voltammetry (CV), square-wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS), were employed. The aptasensor exhibited significant selectivity for PSA, as demonstrated by its ability to distinguish PSA from other components like glucose, carcinoembryonic antigen (CEA), etc. Ultimately, the detection limit (LOD) reached 1.371 ng/mL in the ferrocyanide environment with an R2 value of 0.9777. Furthermore, the labeled electrode in phosphate buffer achieved the remarkable detection limit of 1.566 pg/mL with an R2 value of 0.9676 and linear range of 2.5–12.5 pg/mL, demonstrating the impressive sensitivity and accuracy of the method.

Biochemical recurrence (BCR) and outcomes in patients (pts) with prostate cancer (PC) following radical prostatectomy (RP).

e17112 Background: RP is often the primary treatment option for pts with clinically localized PC. Despite its frequent success, more than 30% of pts eventually present with BCR, defined as detectable prostate-specific antigen (PSA) after RP. BCR is associated with a higher risk of developing distant metastasis and ultimately death. Current patterns of BCR and the impact of BCR on treatment choice and clinical outcomes are not well characterized. Methods: This retrospective cohort study uses nationally representative Optum© Electronic Medical Records (EMR) data from 1/2010 to 9/2021. Eligible pts were adults who underwent RP after PC diagnosis, had ≥ 3 available PSA values after RP, and had EMR activity for at least 6 mo before and 12 mo after RP. Pts with prior malignancy except nonmelanoma skin cancers and pts with metastatic PC at baseline (BL) or within 3 months after RP were excluded. The BL period was 6 mo before RP. Primary outcome was frequency of BCR (defined as PSA ≥ 0.2 ng/mL); secondary analyses included % of pts who progressed to metastasis, castration-resistant PC (CRPC), and death after BCR, and factors associated with time to BCR. Results: 15,198 pts who underwent RP were included in this analysis. Key pt characteristics/outcomes are shown in the Table. Median (range) age was 63.0 (36-88) y, 85.9% of pts were White, and 10.0% were African American. Median (Q1-Q3) follow-up was 3.9 (2.4-5.7) y, and 14.3% of pts had subsequent adjuvant/salvage radiation therapy (RT). Overall, 19.8% of all pts and 61.4% of the subgroup of 2,178 pts with subsequent RT developed BCR. Among pts with BCR (n = 3,016), 16.3% had a PSA doubling time ≤ 10 mo, 17.1% developed metastasis, 13.8% developed CRPC, and 9.7% died. In multivariate Cox regression models (Table), the BL factors associated with an increased risk of developing BCR were PSA 10- < 20 or ≥ 20 ng/mL, Charlson comorbidity index (CCI) > 0, age ≥ 65, African American race, public insurance, and living in the US South region. Conclusions: This real-world (RW) study evaluates the occurrence of BCR in pts who underwent RP with a curative intent from a large US database. This study confirms BL PSA as an important prognostic marker for BCR. A considerable % of pts with BCR developed metastatic PC (17%) or died (10%) during the study period. Novel treatment strategies are needed to delay BCR and further progression to advanced PC among pts with high-risk localized disease. [Table: see text]

Ag NC and Ag NP/PorC Film-Based Surface-Enhanced Raman Spectroscopy-Type Immunoassay for Ultrasensitive Prostate-Specific Antigen Detection.

Surface-enhanced Raman scattering (SERS) is a spectral detection technology with high sensitivity and detectivity and can be used to detect the fingerprint information of the molecules with ultralow concentration. Herein, a kind of immunostructure constructed by Ag nanoparticle/porous carbon (Ag NP/PorC) films as the immunosubstrate and Ag NCs as the immunoprobes was presented for ultralow level prostate-specific antigen (PSA) detection. Experimentally, the Ag NP/PorC film was first prepared with a facile method by carbonizing the gelatin-AgNO3 film in air, and Ag NCs were synthesized by the hydrothermal method. Then, the Ag NP/PorC film was modified by PSA antibodies as the substrate, while Ag NCs were decorated by R6G and PSA antibodies for probes. The sandwiched SERS detection embodiment was constructed by the immunoreaction between the PSA and PSA antibody predecorated on the substrate and probes. Our results show that the proposed SERS-type immunoassay is highly sensitive and selective to a wide range of PSA concentrations from 10-5 to 10-12 g/mL. Thereafter, it was also implemented to detect the PSA level in human serum, and the results successfully reproduce the PSA levels as those measured by the chemiluminescence method with a recovery rate above 90%. All in all, this SERS-type immunoassay provides a promising method for the early diagnosis of prostate cancer.

Cu-MOFs/GOx Bifunctional Probe-Based Synergistic Signal Amplification Strategy: Toward Highly Sensitive Closed Bipolar Electrochemiluminescence Immunoassay.

A closed bipolar electrochemiluminescence (BP-ECL) platform for sensitive prostate specific antigen (PSA) detection was proposed based on a novel synergistic signal amplification strategy. Specifically, glucose oxidase-loaded Cu-based metal-organic frameworks (Cu-MOFs/GOx) as bifunctional probes were bridged on the anodic interface with the target PSA as the intermediate unit. In virtue of the large loading capacity of Cu-MOFs, a large amount of a co-reactant, i.e., H2O2 in this L-012-based ECL system and gluconic acid were generated on the anodic pole in the presence of glucose. The generated gluconic acid could effectively degrade the Cu-MOFs to release Cu2+ which greatly accelerates the formation of highly active intermediates from co-reactant H2O2, boosting the ECL intensity. As for the cathodic pole, K3Fe(CN)6 with a lower reduction potential is used to reduce the driving voltage and speed up the reaction rate, further strengthening the ECL intensity. Thanks to the synergistic signal amplification effect at both two electrode poles of the BP-ECL system, highly sensitive detection of PSA was realized with a detection limit of 5.0 × 10-14 g/mL and a wide linear range of 1.0 × 10-13-1.0 × 10-7 g/mL. The strategy provides a novel way for signal amplification in the BP-ECL biosensing field.

Versatile FeMoOv nanozyme bipolar electrode electrochemiluminescence biosensing and imaging platform for detection of H2O2 and PSA

In this work, a unique FeMoOv nanozyme-bipolar electrode (NM-BPE) electrochemiluminescence (ECL) biosensing and imaging platform was proposed for the first time to realize sensitive detection of target hydrogen peroxide (H2O2) and prostate specific antigen (PSA). Considering the advantage that the cathode and anode poles of the bipolar electrode (BPE) can be modified respectively, this work was carried out using anode equipped with ECL reagent bipyridine ruthenium (Ru(bpy)32+), and cathode equipped with the Fe-doped molybdenum oxide/Au nanoparticles (FeMoOv/AuNPs) with excellent peroxidase (POD) and catalase (CAT)-like activity. Because FeMoOv/AuNPs show efficient enzyme catalysis effect and can greatly promote the decomposition of H2O2, thus the electron transfer rate in the NM-BPE system would be much accelerated to enhance the ECL signal of Ru(bpy)32+. Based on this principle, this work not only realized sensitive detection of H2O2, but also ingeniously designed an sandwich immunosensor using FeMoOv/AuNPs as recognition probe to mediate the ECL response on the anode, achieving highly sensitive detection of PSA. Furthermore, a unique mobile phone ECL imaging system was developed for assay of PSA at different concentrations, which opened a new portable imaging sensing device for bioassays. This work was the first time to combine nanozymes with bipolar electrodes for ECL analysis and imaging, which not only broadened the applications of nanozymes, but also pioneered the new joint ECL research technique of bipolar electrode and ECL imaging in bioassays, showing great application prospect for multiple detection of proteins, nucleic acids and cancer cells.

Electrochemical sensing interface based on the oriented self-assembly of histidine labeled peptides induced by Ni2+ for protease detection

To construct an electrochemical sensing interface which was convenient for protease recognition and cleavage, we designed a strategy for directed self-assembly of histidine-tagged peptides on the electrode led by Ni2+ ions for electrochemical detection of prostate specific antigen (PSA). The electrode surface was first functionalized using carboxylated multiwalled carbon nanotubes and then modified with the metal ion chelating agent (5 S)–N-(5-Amino-1-carboxypentyl) iminodiacetic acid (NIA). After the Ni2+ was captured by NIA, the designed immune-functional peptide could be oriented assembly to the electrode interface through the imidazole ring of histidine at the tail, completing the construction of the recognition layer. Therefore, by adding the analyte PSA to identify and shear the immune-functional peptide, the ferrocene in its head was released, resulting in a reduction in the electrical signal, enabling sensitive detection. In addition, the self-assembly layer could be removed by pickling to realize the reconstruction of the recognition layer. Under optimal conditions, the electrochemical sensor had an ultralow detection limit of 11.8 fg mL−1 for PSA, with a wide detection range from 1 pg mL−1 to 100 ng mL−1. In this work, an electrochemical sensing interface based on the histidine-tagged peptide induced by Ni2+ was formed to enable controllable oriented assembly on the electrode surface, and the recognition layer could be reconstructed via pickling, providing a potential approach for the design of repeatable interfaces.

Highly Efficient Signal On/Off Electrochemiluminescence Gel Aptasensor Based on a Controlled Release Strategy for the Sensitive Detection of Prostate Specific Antigen.

The controlled release strategy can make the constructed sensor have the function of self-on/off, which has an obvious effect on improving the sensitivity in immunoassays. Metal organic gels (MOGs) are the most noteworthy. They are materials with ultrahigh surface area, highly dispersed atomical metal sites, and well-defined porosity and can be used as an efficient luminophore to cause the developed sensor to have good hydrophilicity and adjustability, thus further improving the detection sensitivity. In this work, a novel on/off electrochemiluminescence (ECL) gel aptasensor was constructed using the Cys-[Ru(dcbpy)3]2+ gel as a luminophore, ZnS quantum dots (QDs) as quenchers, and aminated mesoporous silica nanocontainers (SiO2-NH2) as carriers of controlled release for prostate specific antigen (PSA) detection. Specifically, the ssDNA and PSA aptamer made up clamp-like molecules to block holes of the SiO2-NH2 after encapsulating the quencher ZnS QDs. Because of the specific binding between the PSA antigen and aptamer, the clamp-like molecules of ssDNA and the PSA aptamer were disassembled. Finally, the release of ZnS QDs was triggered, thereby realizing a self-off mode of the ECL signals under a co-reactant-free environment by ECL resonance energy transfer (ECL-RET) between the Cys-[Ru(dcbpy)3]2+ and ZnS QDs. In addition, the quenching mechanism was confirmed by molecular orbitals from the theoretical calculation level. The detection limit of the gel aptasensor for PSA was as low as 1.01 fg/mL, showing excellent sensitivity and accuracy. These strategies provided a feasible idea for PSA and even other tumor marker immunoassays.

Smartphone-based photoelectrochemical immunoassay of prostate-specific antigen based on Co-doped Bi2O2S nanosheets

Portable and on-site detection of target biomarker is of great significance in early diagnosis of diseases. Herein, we designed a portable smartphone-based PEC immunoassay platform to detect prostate specific antigen (PSA) adopting Co-doped Bi2O2S nanosheets as photoactive materials. The fast photocurrent response under visible light and excellent electrical transport rate invest Co-doped Bi2O2S with the property of being effectively excited even under a weak light source. Therefore, with the incorporation of a carriable flashlight that act as the excitation light source, disposable screen-printed electrodes, a microelectrochemical workstation and a smartphone that served as control center, point-of-care analytical detection of low-abundance small molecule analytes was successfully realized. Specifically, a sandwich-type immunoreaction was performed using alkaline phosphatase labeled secondary antibody as signal indicator. In the presence of PSA, ascorbic acid as generated through a catalytic reaction, resulting in the enhancement of photocurrent intensity. The photocurrent intensity increased linearly with the logarithm of PSA concentrations ranging from 0.2 to 50 ng mL−1 with a detection limit of 71.2 pg mL−1 (S/N = 3). This system provided an effective method for the construction of portable and miniaturized PEC sensing platform for the application of point-of-care health monitoring.

Bio-inspired nanozyme with ultra-thin Fe–Bi2O2S nanosheets for in-situ amplified photoelectrochemical immunoassay of cancer-related protein

A Fe-loaded Bi2O2S nanosheet photoanode serving as photoelectric biomonitoring platform for the detection of prostate-specific antigen (PSA) using biologically inspired prussian nanoparticle (PB)-catalyzed biocatalytic precipitation strategy was developed. Primarily, the signal probe PB-mAb2 obtained by electrostatic adsorption was immobilized on a microplate in the presence of target PSA, and 4-chloro-1-naphthol (4-CN) was oxidized to benzo-4-chloro-hexadienone (4-CD) with the assistance of exogenous hydrogen peroxide, which was generated by a large number of hydroxyl radicals catalyzed by PB. The generated 4-CD showed strongly low conductivity characteristics to burst the photocurrent of highly photoactive Fe–Bi2O2S photoanode. The split incubation reaction could be suitable for high volume and low-cost rapid detection. A dynamic response range of 0.1–100 ng mL−1 with a limit of detection of 34.2 pg mL−1 was achieved with the sensor based on a photoelectric sensing platform and a biomimetic catalytic precipitation reaction. Equally important, the sensor also showed good potential in the detection of real samples compared to commercially available ELISA kits. In conclusion, this work provides a fresh scheme for the development of sensitive biosensors through a bio-inspired catalytic strategy of versatility and a photoanode coupling with high photoelectric activity.

Shrink polymer based electrochemical sensor for point-of-care detection of prostate-specific antigen

There is a growing but unmet need for point-of-care detection of prostate-specific antigen (PSA) in body fluid which may facilitate early diagnosis and therapy of prostate cancer in a cost-effective and user-friendly way. Low sensitivity and narrow detection range limits applications of point-of-care testing in practice. Here, an immunosensor is first presented based on shrink polymer and integrated into a miniaturized electrochemical platform for detecting PSA in clinical samples. The sensing electrode was prepared by sputtering a gold film on shrink polymer, followed by heating to shrink the electrode to a small size with wrinkles from nano-scale to micro-scale. These wrinkles can be directly regulated by the thickness of the gold film with high specific areas for enhancement of antigen-antibody binding (3.9 times). A distinct difference between electrochemical active surface area (EASA) and response to PSA of shrink electrodes was observed and discussed. The electrode was treated with air plasma and modified with self-assembled graphene to further enhance the sensor's sensitivity (10.4 times). The shrink sensor with gold 200 nm thick integrated into the portable system was validated by a label-free immunoassay for detection of PSA in 20 μL serum within 35 mins. It exhibited a limit of detection of 0.38 fg/mL, the lowest among label-free PSA sensors, and a wide linear response from 10 fg/mL to 1000 ng/mL. Moreover, the sensor demonstrated reliable assay results in clinical serums, comparable to the commercial chemiluminescence instrument, confirming its feasibility for clinical diagnosis.

An ultrasensitive FET biosensor based on vertically aligned MoS2 nanolayers with abundant surface active sites

Molybdenum disulfide (MoS2) nanolayers are one of the most promising two-dimensional (2D) nanomaterials for constructing next-generation field-effect transistor (FET) biosensors. In this article, we report an ultrasensitive FET biosensor that integrates a novel format of 2D MoS2, vertically-aligned MoS2 nanolayers (VAMNs), as the channel material for label-free detection of the prostate-specific antigen (PSA). The developed VAMNs-based FET biosensor shows two distinctive advantages. First, the VAMNs can be facilely grown using the conventional chemical vapor deposition (CVD) method, permitting easy fabrication and potential mass device production. Second, the unique advantage of the VAMNs for biosensor development lies in its abundant surface-exposed active edge sites that possess a high binding affinity with thiol-based linkers, which overcomes the challenge of molecule functionalization on the conventional planar MoS2 nanolayers. The high binding affinity between 11-mercaptoundecanoic acid and the VAMNs was demonstrated through experimental surface characterization and theoretical calculations via density functional theory. The FET biosensor allows rapid (within 20 min) and ultrasensitive PSA detection in human serum with simple operations (limit of detection: 800 fg mL−1). This FET biosensor offers excellent features such as ultrahigh sensitivity, ease of fabrication, and short assay time, and thereby possesses significant potential for early-stage diagnosis of life-threatening diseases.

Combined Use of Ionic Liquid-Based Aqueous Biphasic Systems and Microfluidic Devices for the Detection of Prostate-Specific Antigen.

Prostate cancer (PCa) is one of the cancer types that most affects males worldwide and is among the highest contributors to cancer mortality rates. Therefore, there is an urgent need to find strategies to improve the diagnosis of PCa. Microtechnologies have been gaining ground in biomedical devices, with microfluidics and lab-on-chip systems potentially revolutionizing medical diagnostics. In this paper, it is shown that prostate-specific antigen (PSA) can be detected through an immunoassay performed in a microbead-based microfluidic device after being extracted and purified from a serum sample through an aqueous biphasic system (ABS). Given their well-established status as ABS components for successful bioseparations, ionic liquids (ILs) and polymers were used in combination with buffered salts. Using both IL-based and polymer-based ABS, it was demonstrated that it is possible to detect PSA in non-physiological environments. It was concluded that the ABS that performed better in extracting the PSA from serum were those composed of tetrabutylammonium chloride ([N4444]Cl) and tetrabutylphosphonium bromide ([P4444]Br), both combined with phosphate buffer, and constituted by polyethylene glycol with a molecular weight of 1000 g/mol (PEG1000) with citrate buffer. In comparison with the assay with PSA prepared in phosphate-buffered saline (PBS) or human serum in which no ABS-mediated extraction was applied, assays attained lower limits of detection after IL-based ABS-mediated extraction. These results reinforce the potential of this method in future point-of-care (PoC) measurements.

Efficacy and safety of apalutamide in patients with metastatic castration-resistant prostate cancer (GENESIS): protocol for a multicentre, open-label, single-arm clinical trial

IntroductionThis is a multicentre, open-label, single-arm clinical trial to evaluate the efficacy and safety of apalutamide in patients with metastatic castration-resistant prostate cancer.Methods and analysisThe trial will be performed at...

The development of a fluorescence/colorimetric biosensor based on the cleavage activity of CRISPR-Cas12a for the detection of non-nucleic acid targets

Nano-biosensors are of great significance for the analysis and detection of important biological targets. Surprisingly, the CRISPR-Cas12a system not only provides us with excellent gene editing capabilities, it also plays an important role in biosensing due to its high base resolution and high levels of sensitivity. However, most CRISPR-Cas12a-based sensors are limited by their recognition and output modes, are therefore only utilized for the detection of nucleic acids using fluorescence as an output signal. In the present study, we further explored the potential application of CRISPR-Cas12a and developed a CRISPR-Cas12a-based fluorescence/colorimetric biosensor (UCNPs-Cas12a/hydrogel-MOF-Cas12a) that provides an efficient targeting system for small molecules and protein targets. These two sensors yield multiple types of signal outputs by converting the target molecule into a deoxyribonucleic acid (DNA) signal input system using aptamers, amplifying the DNA signal by catalyzed hairpin assembly (CHA), and then combining CRISPR-Cas12a with various nanomaterials. UCNPs-Cas12a/hydrogel-MOF-Cas12a exhibited prominent sensitivity and stability for the detection of estradiol (E2) and prostate-specific antigen (PSA), and was successfully applied for the detection of these targets in milk and serum samples. A major advantage of the hydrogel-MOF-Cas12a system is that the signal output can be observed directly. When combined with aptamers and nanomaterials, CRISPR-Cas12a can be used to target multiple targets, with a diverse array of signal outputs. Our findings create a foundation for the development of CRISPR-Cas12a-based technologies for application in the fields of food safety, environmental monitoring, and clinical diagnosis.

Bioorthogonal chemistry-based high-efficient quantum dots binding boosts the detection sensitivity of plasmon-enhanced fluorescence platform for immunoassay

Although plasmon-enhanced fluorescence (PEF) technology has been demonstrated its potential in protein detection for disease early diagnosis, its detection sensitivity still has a big gap compared to that of methods featured with single-molecule detection ability. Herein, inspired by the properties of catalyst-free bioorthogonal chemistry between 1,2,4,5-tetrazine (Tz) and trans-cyclooctene (TCO) being capable of improving the nanoparticle binding efficiency, we initially incorporate semiconductor quantum dots (QDs) into PEF-based suspension microarray platform as the signal reporter and evaluate its performance for biomarker prostate-specific antigen (PSA) detection by comparing with traditional fluorescence protein-based methods. In our assay, Tz-tagged QDs could be readily absorbed onto the sandwich immunocomplex composed of capture antibody, target PSA and TCO-labelled detection antibody for signal output. To improve the QDs binding efficiency, detection performance obtained from QDs-conjugated detection antibody as the reporter prepared by the same bioorthogonal chemistry reaction was also evaluated. For the evaluation of its potential in practical application, the performance including detection sensitivity and dynamic range of the proposed method for PSA assay in clinical sera samples using commercially-available PEF-based planar microarray as the control was discussed, which revealed that the nanoparticle-binding efficiency base on traditional SA/avidin method could be dramatically improved by the proposed method.

A sensitive label-free biosensor based on Ag2S-sensitived Bi2WO6/BiOBr heterojunction for photoelectrochemical immunoassay of prostate specific antigen

Prostate cancer is one of the most common cancers in the world, and its early diagnosis can effectively reduce mortality. A new label-free photoelectrochemical (PEC) immunosensor on the basis of Bi2WO6/BiOBr nanocomposite materials has been successfully prepared for the test of prostate-specific antigen (PSA) in human serum in this work. The Ag2S-sensitized Bi2WO6/BiOBr heterojunction was used as a photosensitive material, which effectively improved the photocurrent response. On Bi2WO6/BiOBr surface, dopamine immobilized PSA antibody by self-polymerizing to form polydopamine membrane. Antigen and antibody are specifically combined to achieve quantitative detection of PSA according to the current changes at different concentrations of antigen. Under the optimal experimental conditions, the PEC immunosensor has an ideal linear relationship between 1 pg/mL - 50 ng/mL, and the detection limit is 0.084 pg/mL. In addition, the prepared immunosensor has good stability, reproducibility and selectivity, providing a new method for the detection of PSA in actual sample analysis.

Highly sensitive sensing detection of prostate-specific antigen based on point-of-care electrochemical immunosensor

Assembling point-of-care (POCT) sensors is a people topic in medical testing. In this work, a POCT electrochemical sensor was assembled for the rapid detection of prostate-specific antigen (PSA). Screen-printed electrodes were used as a base for the sensor due to their cheap cost. PEDOT and ds-DNA were used to increase the deposition of Ag nanoparticles (NPs). The immunosensor with sandwich structure was assembled on AgNPs/ds-DNA/PEDOT to achieve highly sensitive detection of PSA. H2O2 was used as a probe to reflect the PSA concentration. Under optimal conditions, the assembled immunosensor can detect PSA between 0.1 pg/mL and 100 ng/mL. The detection limit can reach 17 fg/mL.

Fertility Desire and Associations with Condomless Sex, Antiretroviral Adherence, and Transmission Potential in a Cohort of Kenyan Women Living with HIV in Sero-discordant Relationships: A Mixed Methods Study

For women living with HIV (WLH) in serodiscordant partnerships, decisions about childbearing can challenge condom use and antiretroviral adherence. In a prospective cohort of 148 WLH in serodiscordant partnerships, 58 (39%) wanted more children in the future but were not currently trying to conceive (fertility desire), and 32 (22%) were currently trying to become pregnant (fertility intent). Detection of prostate specific antigen (PSA) in vaginal secretions, a marker for recent condomless sex, was lowest in women with fertility desire and highest in women with fertility intent. Detectable viral load followed a similar pattern. Risk of HIV transmission, when condomless sex and PSA detection occurred concurrently, was three to fourfold higher at visits with fertility intent compared to visits with fertility desire. Qualitative interviews underscored the importance women place on childbearing and suggested that they had limited information about the role of antiretroviral therapy in reducing sexual HIV transmission.

Sensitive determination of prostate-specific antigen with graphene quantum dot-based fluorescence aptasensor using few-layer V2CTx MXene as quencher

A novel fluorescence aptasensor of prostate-specific antigen (PSA) was established using few-layer vanadium carbide (FL-V2CTx) nanosheet as a quencher. First, FL-V2CTx was prepared by the delamination of multi-layer V2CTx (ML-V2CTx) with tetramethylammonium hydroxide. The aptamer-carboxyl graphene quantum dots (CGQDs) probe was prepared by combining the aminated PSA aptamer and CGQDs. Then, the aptamer-CGQDs were absorbed onto the surface of FL-V2CTx by hydrogen bond interaction, which led to the decrease in fluorescence of aptamer-CGQDs due to photoinduced energy transfer. After addition of PSA, PSA-aptamer-CGQDs complex was released from FL-V2CTx. The fluorescence intensity of aptamer-CGQDs-FL-V2CTx with PSA was higher than that without PSA. The FL-V2CTx-based fluorescence aptasensor provided a PSA detection linear range from 0.1 to 20 ng mL−1 with detection limit of 0.03 ng mL−1. The ΔF value of fluorescence intensities for aptamer-CGQDs-FL-V2CTx with and without PSA was 5.6, 3.7, 7.7, and 5.4 times of ML-V2CTx, few-layer titanium carbide (FL-Ti3C2Tx), ML-Ti3C2Tx and graphene oxide aptasensors, respectively, indicating the advantage of FL-V2CTx. The aptasensor had high selectivity for PSA detection compared with some proteins and tumor markers. This proposed method had convenience and high sensitivity for PSA determination. The determination results of PSA in human serum samples using the aptasensor were consistent with those by chemiluminescent immunoanalysis. The fluorescence aptasensor can be successfully applied for PSA determination in serum samples of prostate cancer patients.

A novel fluorescence aptasensor based on PCN-223 as an efficient quencher for sensitive determination of prostate-specific antigen.

A novel fluorescence aptasensor based on PCN-223 as an efficient quencher was developed to sensitively detect prostate-specific antigen (PSA). The 5-carboxytetramethylrhodamine (TAMRA)-labeled PSA aptamer was adsorbed on PCN-223 by π-π stacking and hydrogen-bonding interactions, which contributed to fluorescence quenching because of the photoinduced electron transfer from TAMRA to PCN-223. In addition, the amount ofquenched fluorescence of the PSA-binding aptamer complex-PCN-223 was lower than that of TAMRA aptamer-PCN-223 without PSA (at excitation/emission peaks of 545/582nm), which can be explained by the factthat the PSA-binding aptamer complexes contributed to the separation of the aptamer from PCN-223. ∆F value of fluorescence intensities for TAMRA aptamer-PCN-223 with and without PSA showed a good linear relationship with PSA concentration over a range of 0.1 to 24ngmL-1, with a detection limit of 0.05ngmL-1. Compared with three metal-organic frameworks (MOFs) of UiO-66-NH2, ZIF-67, and Ni3(HITP)2 as quenchers, PCN-223 as a Zr-MOF exhibited the highest ∆F value for PSA detection. The advantage of PCN-223 could be attributed to its carboxyl, benzene, and porphyrin groups, the large specific surface area and good biocompatibility. This proposed aptasensor can be successfully used to detect PSA in sera of prostate cancer patients. The PSA detection results of this aptasensor were consistent with those which were obtained from hospital by Archtecti2000sr automatic chemiluminescence immunoanalyzer. The proposed aptasensor has potential clinical detection application.