Prostate-specific Antigen Determination Research Articles

A self-powered photoelectrochemical aptasensor based on target response and Ag-CdIn2S4 photosensitive material for ultrasensitive detection of prostate-specific antigen

In this study, Ag-CdIn2S4 was selected as a photosensitive material and combined with the zeolite imidazole frame-90 encapsulated methylene blue (ZIF-90@MB) to establish a controlled release system. On that basis, a self-powered photoelectrochemical (PEC) aptasensor was constructed based on target responses to realize the highly sensitive detection of prostate-specific antigen (PSA). The self-powered sensing method was employed to effectively avoid interference from other oxidizing/reducing substances in the system and improve the accuracy of the detection method. The band gap of CdIn2S4 was adjusted by Ag doping, and the visible light absorption capacity and photoelectric conversion efficiency of the material were improved by the local surface plasmon resonance (LSPR) effect of metal Ag. The ZIF-90 porous material was used as a carrier, the MB photosensitizer as a signal molecule was loaded in the ZIF-90 pore channel. The PSA aptamer (PApt) was attached to the ZIF-90@MB surface to form a simple biological gate. In the presence of the PSA, the recognition interaction between PApt and PSA made the biological gate open, then many MB molecules were released from ZIF-90 and enhanced the photocurrent signal. Under the optimal experimental conditions, the linear range of the sensor was 0.005 ∼ 50 ng mL−1, and the detection limit was 2.35 pg mL−1. The accurate determination of PSA in human serum was achieved, which provided a novel sensing strategy for the early diagnosis of clinical biomarkers.

Fe-single-atom catalysts boosting electrochemiluminescence via bipolar electrode integrated with its peroxidase-like activity for bioanalysis

Multifunctional single-atom catalysts (SACs) have been extensively investigated as outstanding signal amplifiers in bioanalysis field. Herein, a type of Fe single-atom catalysts with Fe-nitrogen coordination sites in nitrogen-doped carbon (Fe–N/C SACs) was synthesized and demonstrated to possess both catalase and peroxidase-like activity. Utilizing Fe–N/C SACs as dual signal amplifier, an efficient bipolar electrode (BPE)-based electrochemiluminescence (ECL) immunoassay was presented for determination of prostate-specific antigen (PSA). The cathode pole of the BPE-ECL platform modified with Fe–N/C SACs is served as the sensing side and luminol at the anode as signal output side. Fe–N/C SACs could catalyze decomposition of H2O2 via their high catalase-like activity and then increase the Faraday current, which can boost the ECL of luminol due to the electroneutrality in a closed BPE system. Meanwhile, in the presence of the target, glucose oxidase (GOx)-Au NPs-Ab2 was introduced through specific immunoreaction, which catalyzes the formation of H2O2. Subsequently, Fe–N/C SACs with peroxidase-like activity catalyze the reaction of H2O2 and 4-chloro-1-naphthol (4-CN) to generate insoluble precipitates, which hinders electron transfer and then inhibits the ECL at the anode. Thus, dual signal amplification of Fe–N/C SACs was achieved by increasing the initial ECL and inhibiting the ECL in the presence of target. The assay exhibits sensitive detection of PSA linearly from 1.0 pg/mL to 100 ng/mL with a detection limit of 0.62 pg/mL. The work demonstrated a new ECL enhancement strategy of SACs via BPE system and expands the application of SACs in bioanalysis field.

Serum Levels of Prostate Specific Antigen and Specific Reproductive Hormones Among Male Subjects with Benign Prostate Hyperplasia in Port Harcourt, Nigeria

Benign prostate hyperplasia (BPH) is a medical condition in elderly men in which there is proliferation and enlargement of the prostate gland. This study evaluated the levels of male reproductive hormones among subjects with BPH. The study involved 150 subjects aged 40 years and above, comprising 80 BPH subjects attending the urology clinic and 70 control subjects. Five millilitres (5ml) of venous blood were collected from each subject into plain bottles for the determination of prostate-specific antigen (PSA), testosterone, prolactin, and estradiol, using the ELISA technique. The mean values of PSA (16.68±10.96 ng/ml), estradiol (71.03±18.56 pg/ml) and for the BPH subjects and prolactin (9.38±4.51 ng/ml) were significantly higher compared to the mean values of PSA (0.48±0.25ng/ml), estradiol (51.33±7.13npg/ml) and prolactin (6.92±1.93ng/ml) of the control subjects. However, the mean testosterone value of the BPH subjects (5.02±1.93 ng/ml) was significantly lower than the mean value for the control (6.57±3.48ng/ml). The BPH who used to consume alcohol had higher PSA (24.26±8.33ng/ml) and testosterone (7.68±3.41ng/ml) compared to the PSA (16.34±3.22ng/ml) and testosterone (4.95±3.62ng/ml) of those who never consumed alcohol. The BPH had significantly altered hormone parameters as well as raised PSA levels. Including hormonal parameters in diagnosing and managing BPH could be an important consideration in our population.

Target-aptamer binding triggered isothermal strand displacement polymerase reaction for prostate specific antigen detection

For the purpose of detecting prostate specific antigen (PSA), a ratiometric electrochemical aptasensor has been developed based on target-aptamer binding triggered isothermal strand displacement polymerase reaction (ISDPR). A ferrocene (Fc)-modified hairpin probe 2 (Fc-HP2) was self-assembled on the modified electrode surface. One terminus of hairpin probe 1 (HP1) bound to PSA and formed the HP1/PSA complex, and the other hybridized with Fc-HP2. Then, the S1 strand hybridized with the stem of Fc-HP2 and was extended with the aid of phi29 DNA polymerase (phi 29) and deoxyribonucleoside triphosphates (dNTPs), and the HP1/PSA complex could be displaced to trigger a new cycle of polymerization reaction. Finally, numerous double-stranded DNAs (dsDNAs) were produced for methylene blue (MB) intercalation. With the raising of PSA concentrations, the electrochemical responses of Fc (IFc) and MB (IMB) decreased and increased, respectively. When IMB/IFc was used as the response signal for quantitative determination of PSA, the proposed strategy possessed a wide linear range (10 pg mL−1–100 ng mL−1) and a low detection limit of 3.2 pg mL−1. Moreover, the proposed aptasensor displayed good performance for PSA determination in spiked human serum samples, showing great application prospects in bioanalysis.

Ratio fluorescence/colorimetric dual mode aptasensor and smartphones-assisted miniaturized device for early diagnosis of prostate cancer

Prostate specific antigen (PSA) is the most common tumor biomarker for prostate cancer (PCa), and its precise determination is essential to improving survival rate and reducing treatment cost of cancer patient. Here, we have proposed a novel ratio fluorescence/colorimetric dual mode aptasensor based on CdTe-apt + B-CDs + ZrFe MOF system for PSA determination. Specifically, as-prepared ZrFe MOF with good peroxidase like activity can quench the fluorescence of B-CDs + CdTe-apt system via inner filter effect (IFE), while the existence of PSA can restore fluorescence of CdTe-apt but virtually unchanged fluorescence of B-CDs due to specific identification between PSA and aptamer. Similarly, the addition of PSA can recover the peroxidase like activity of ZrFe MOF which is significantly suppressed by PSA aptamer. Based on this, the proposed ratio fluorescence/colorimetric dual mode aptasensor has achieved satisfactory results in PSA analysis of serum specimens. Valuably, an inexpensive, portable but credible smartphones-assisted miniaturized device is expected to be exploited for the early diagnosis of PCa, inspiring the design and construction of advanced portable devices for self-monitoring and home screening of various cancers.

Synergetic surface enhancement of quantum dots-based electrochemiluminescence with photonic crystal light scattering and metal surface plasmon resonance for sensitive bioanalysis

Noble metal nanostructures and photonic crystals (PhCs) have been widely investigated as substrates for constructing surface enhanced electrochemiluminescence (SE-ECL) biosensors. However, their applications are hindered by the limited enhancement intensity of surface plasmon resonance (SPR) and an incomplete mechanism for the photonic enhancement effect. Hence, developing a novel SE-ECL strategy with better signal enhanced capability and enriching our understanding of the intrinsic mechanisms for efficient bioanalysis is extremely urgent.Here, a synergistic SE-ECL strategy was developed for the sensitive determination of prostate specific antigen (PSA) protein. The randomly arranged polystyrene (r-PS) spheres and PS PhC arrays were applied to enhance the ECL emission of cadmium sulfide quantum dots (CdS QDs) and the results suggested that the PhC arrays displayed superior intensity (0.22) than the r-PS interface (0.10). Au nanoparticles (NPs) were introduced onto the two kinds of surfaces and further boosted the ECL intensity. According to the ECL measurements, Au NPs modified at the r-PS surface exhibited only a slight increase (0.13), while the PhC arrays showed approximately 5-fold enhancement (0.92), benefiting from the synergistic enhancement. The finite-difference time-domain (FDTD) simulation indicated that the ECL enhancement was ascribed to the coupled electromagnetic (EM) field at the surfaces of PS PhCs and Au NPs. The SE-ECL could achieve a detection range from 1 pg/mL to 1 μg/mL with a detection limit of 0.41 pg/mL (S/N = 3).This study provides the first combination of PhC arrays and metal surface plasmon nanostructure for the synergetic enhancement of SE-ECL systems. It opens a new avenue for the rational design of advanced ECL biosensors and shows great perspective for clinical diagnosis.

Incidental carcinoma of the prostate in cystoprostatectomy specimens - is it always a toothless lion?

Incidental prostate carcinoma (iPC) is a subject of debate concerning its definition, incidence, biology, diagnosis, staging, and treatment. The present study aimed to assess the incidence and main clinical-morphological characteristics of iPC identified in radical cystoprostatectomy (RCP) specimens over a 5-year period. Using the database of the Urology and Pathology Departments, we identified all patients with bladder carcinomas (BCs) who underwent RCP within a 5-year frame time. We selected only those patients with synchronous BC and prostate carcinoma (PC). The following parameters were analyzed for these patients: age, type of bladder and prostate tumor, degree of differentiation, pathological stage, and other prognostic parameters. We identified 91 men with bladder tumors treated by RCP among whom 43, aged between 53 and 84 years (mean age: 69.2 years), presented synchronous PC. iPC was more prevalent in older individuals (>65 years: 30 patients, 69.8%), with only six out of the 43 (12.8%) patients with iPC being aged ≤60 years. All iPC cases were conventional adenocarcinoma. Well-differentiated prostate adenocarcinomas (grade group 1) predominated (65.1%). Among the 43 iPCs, 16 (37.2%) were clinically significant PCs. iPC is frequently identified in patients with BC when inclusion and evaluation of all or most of the prostate tissue are performed. Although more than half of iPCs were well-differentiated tumors confined to the prostate, a significant number of cases met the criteria of clinically significant PC. All men over the age of 50 who are candidates for RCP, should undergo evaluation through serum prostate specific antigen determination.

Point-of-Care Prostate Specific Antigen Testing: Examining Translational Progress toward Clinical Implementation.

Prostate cancer (PCa) is the second most common male cancer and is attributable to over 375,000 deaths annually. Prostate specific antigen (PSA) is a key biomarker for PCa and therefore measuring patient PSA levels is an important aspect of the diagnostic pathway. Automated immunoassays are currently utilized for PSA analysis, but they require a laboratory setting with specialized equipment and trained personnel. This results in high diagnostic costs, extended therapeutic turnaround times, and restrictions on testing capabilities in resource-limited settings. Consequently, there is a strong drive to develop point-of-care (PoC) PSA tests that can offer accurate, low-cost, and rapid results at the time and place of the patient. However, many emerging PoC tests experience a trade-off between accuracy, affordability, and accessibility which distinctly limits their translational potential. This review comprehensively assesses the translational advantages and limitations of emerging laboratory-level and commercial PoC tests for PSA determination. Electrochemical and optical PSA sensors from 2013 to 2023 are systematically examined. Furthermore, we suggest how the translational potential of emerging tests can be optimized to achieve clinical implementation and thus improve PCa diagnosis globally.

Fluorescence self-assembled DNA hydrogel for the determination of prostate specific antigen by aggregation induced emission

In this study, an aptamer-based, functionalized-DNA hydrogel system is developed for prostate-specific antigen (PSA) detection. A pure DNA hydrogel is constructed using specific DNA building blocks and an aptamer as a cross-linker. Firstly, silver nanoclusters (AgNCs) are constructed on the Y-shaped DNA (Y-DNA) building blocks. Then, the DNA hydrogel was formed via the addition of the cross-linker to the Y-DNA solution. In this case, the fluorescence emission of silver nanoclusters that have accumulated in the hydrogel increases due to aggregation-induced emission (AIE). The presence of PSA and its subsequent interaction with its specific aptamer dissolve the hydrogel structures, which leads to a low emission intensity. A great linear relationship was attained in this assay in the range of 0.05 to 8 ng mL−1 with a detection limit of 4.4 pg mL−1 for the detection of PSA. Additionally, the proposed aptasensor was successfully used to detect PSA in human serum samples. The recovery for different concentrations of PSA was in the range of 96.1% to 99.3%, and the RSD range was from 2.3% to 4.5%. Comparing our method to current ones in the field of PSA detection proves that our platform benefits from a simpler procedure, lower cost, and better efficiency, providing high potential for future clinical applications.

Performance enhancement of electrochemiluminescence magnetic microbiosensors by using double magnetic field actuation for cancer biomarkers and exosomes

This work reports the performance enhancement strategies on magnetic beads (MBs)-based electrochemiluminescence (ECL) platforms by using double magnetic field actuation of the ECL magnetic microbiosensors (MMbiosensors) for highly sensitive determination of cancer biomarker and exosomes. To obtain the high sensitivity and reproducibility of the ECL MMbiosensors, a series of strategies have been developed including replacing a conventional photomultiplier tube (PMT) with a diamagnetic PMT, replacing the stacked ring-disc magnets with circular-disc magnets lain-in glassy carbon electrode, adding a pre-concentration process of MBs using external magnet actuation. For fundamental research, the ECL MBs taken as the substitute of ECL MMbiosensors were prepared by binding biotinylated DNA tagged with Ru(bpy)32+ derivative (Ru1) to streptavidin-coated MB(MB@SA) were which showed that the developed strategies can enhance 45-fold sensitivity. Importantly, the developed MBs-based ECL platform was estimated by determination of prostate specific antigen (PSA) and exosomes. For PSA, MB@SA•biotin-Ab1(PSA) was taken as the capture probe and Ru1-labeled Ab2 (PSA) was done as ECL probe, while for exosomes, MB@SA•biotin-aptamer (CD63) was taken as the capture probe and Ru1-labeled Ab (CD9) was done as the ECL probe. The experiment results showed that the developed strategies can enhance 33-fold sensitivity of ECL MMbiosensors for PSA and exosomes. The detection limit is 0.28 ng mL−1 for PSA and 4.9 × 102 particle mL-1 for exosomes. This work demonstrated that a series of proposed magnetic field actuation strategies greatly increase the sensitivity of the ECL MMbiosensors. The developed strategies can be expanded to MBs-based ECL and electrochemical biosensors for clinical analysis with greater sensitivity.

The proportion of false-positives in positive Seratec® prostate-specific antigen SemiQuant test results in postmortem screening for seminal fluid

Prostate-specific antigen (PSA) tests are used in forensics to conduct rapid screening for semen in vaginal swab samples from alleged victims of sexual abuse. Although PSA membrane tests have been applied to autopsy specimens, no study has evaluated predictors of false-positive test results in relation to factors such as age, cause of death, postmortem interval, drugs, and alcohol. This study describes the results obtained with the Seratec® PSA SemiQuant Kit test in 283 deceased women, with or without a history of sexual assault. Overall, 18.4% (52/283) of the vaginal swab samples tested positive for PSA. However, 63.5% (33/52) of the PSA-positive vaginal swab samples had no sperm detected. The proportion of false-positives in positive PSA results was 94.4% in those aged over 60 years. Multivariate logistic regression for PSA-positive samples showed that the proportion of false-positives in positive PSA results increased with the age of the deceased. However, the cause of death, postmortem interval, and presence of drugs or alcohol in the blood or urine of the deceased did not affect the PSA determination. These results show that PSA membrane tests are relatively unreliable and can be misleading, especially when derived from vaginal swab samples of older women, obtained at autopsy. In forensic cases, positive PSA screening test results may have an impact on subsequent legal actions and criminal charges brought against the accused. These findings are important for both forensic pathologists and the police to ensure accurate screening of older women in cases of suspected sex crimes.

Systematic or targeted fusion-guided biopsy

Early detection of prostate cancer (PCa) is associated with ahigh risk for detecting low-risk disease. In the primary biopsy indication, systematic biopsy leads to an increased detection of clinically insignificant PCa, and significant prostate cancers are not detected with sufficient sensitivity, especially without prior magnetic resonance imaging (MRI). Similar data have recently become available for PCa screening. In light of the current literature, this article aims to discuss the data on systematic and combined targeted and systematic multiparametric MRI (mpMRI)-guided fusion biopsy to improve PCa diagnosis in clinically suspected cancer even in screening using multivariable risk stratification. Literature review on mpMRI and MRI/TRUS fusion biopsy (TRUS: transrectal ultrasonography) for tumor detection in suspected prostate cancer and PCa screening was performed. Multiparametric MRI as areflex test after prostate-specific antigen (PSA) determination (PSA cut-off 4 ng/ml) in combination with targeted biopsy alone reduces the detection of clinically nonsignificant tumors in early detection by half. On the other hand, in the form of atarget saturation or in combination with asystematic biopsy, the sensitivity for the detection of cancers of International Society of Urogenital Pathology (ISUP) grade groups2 or higher can be improved. Similar results are also shown in PCa screening with aPSA cut-off of 3 ng/ml. The evidence for performing atargeted fusion biopsy alone is currently insufficient. Therefore, the combination of mpMRI-guided targeted and systematic biopsy continues to be the recommended standard for prostate cancer diagnosis.

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.

Association of Haplotypes in Exon 4 of KLK2 Gene with Raised Serum Prostate-Specific Antigen

The standard diagnostic modalities for Prostate Cancer (PC) include serum Prostate-Specific Antigen (PSA) assay, Digital Rectal Examination (DRE), and histological examination of prostate biopsy. They are limited by low predictive potential and inability to predict which patients are at risk of developing metastatic disease. The aim of this study is to investigate the exon 4 of the KLK2 gene of subjects for changes in its nucleotide sequences (SNPs) and determine the correlation of these changes with serum PSA in an Igbo population of Nigeria. One hundred male subjects aged 40 years and above, who gave their consent, were used for the study. Their PSA determinations were done using ELISA technique while genetic studies were carried out using real-time PCR. tPSA, fPSA, and % fPSA of the subjects ranged between 0.8% - 18.30%, 0.10% - 1.60% and 0.0% - 0.7% respectively. Of the 100 subjects, 28 subjects had tPSA levels above 4.0 ng/ml with a mean of 7.10 (±3.30) ng/ml. Those with tPSA less than 4 ng/ml had a mean of 1.87 (±0.85) ng/m. 15 subjects showed SNPs with a mean tPSA of 6.87 (±4.82) ng/ml while the remaining 85 subjects without SNPs had a mean of 1.86 (±0.80) ng/ml. Results from direct DNA sequencing showed 11 SNPs. Ten subjects are curated in SNP database while one is uncurated. The Chi-square test showed significant association (p = 0.00) between tPSA levels and SNPs mutation (X2 = 17.35, p = 0.00). A Kruskal-Wallis test demonstrated that the positional arrangement of the SNP mutations had no effect on PSA-total or free-values (H (10) = 10.92, p = 0.28; H (10) = 10.07, p = 0.38 respectively). Two SNPs: rs6072 and rs74478031 were associated with elevated PSA levels (p < 0.05). Their presence, therefore, has the potential to serve, in conjunction with raised PSA, as biomarkers of prostate cancer in the study population.

Capacitive label-free ultrasensitive detection of PSA on a covalently attached monoclonal anti-PSA antibody gold surface

• The design of an ultrasensitive label-free detection of prostate specific antigen (PSA) was achieved. • The fabricated immunosensor used monoclonal anti-PSA antibody as capture probe on an electrografted isophthalic thin fim. • Capacitance signals were deconvoluted from the impedance plots and were sensitive to PSA concentrations. • The detection of PSA could be achieved in fg.ml -1 . A rapid, low-cost, and accurate point-of-care analytical device for the determination of prostate-specific antigen (PSA) is required for the early diagnosis and prognosis of prostate cancer (PCa). In this work, an electrochemical capacitive immunosensor was developed for the label-free detection of PSA. The immunosensor was based on the covalent immobilization of monoclonal anti -PSA antibody via carbodiimide chemistry onto gold electrode pre-modified with a thin monolayer film of isophthalic acid (IPA). A methodology based on the steric hindrance of 1,3-substituted aryldiazonium salt was adopted to control the growth of the IPA thin film on the gold electrode. The non-specific binding sites were blocked with bovine serum albumin (BSA) to afford an AuE-IPA- anti -PSA-mAb|BSA immunosensor. The immunosensor was characterized by X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The analytical performance of the developed sensor was evaluated using the capacitance Nyquist plots generated from the complex impedance data. In addition, complex capacitance was also calculated from the imaginary part of the impedance and plotted against the log of frequency. The double layer capacitance from the circuit fitting (R S C) was also used and compared the sensitive capacitance signals to the changes in PSA concentrations. The LOD values were in fg.mL -1 and distinguishable from the blank (PBS) for the Nyquist plots of capacitance, complex capacitance, and double layer capacitance signals. The developed immunosensor exhibited good stability, selectivity, low detection limits, and a wide linear range which was suitable for screening of prostate cancer using prostate-specific antigen.

MIL-88B(Fe)-reduced graphene oxide as an artificial enzyme for gold nanorod etching and its application to develop the prostate-specific antigen immunosensor.

Animmunosensor based on gold nanorods (AuNRs) etchant activity of a metal-organic framework (MOF): MIL-88B(Fe)-reduced graphene oxide (rGMOF) was developed for the determination of prostate-specific antigen (PSA). Several techniques, including FTIR, UV-Vis spectrophotometry, XRD, and electron microscopy, were employed to characterize the MOFs containing iron-oxygen clusters on the surface of reduced graphene oxide. Enzyme mimetic activity of rGMOF before and after bioconjugation with antibodies was calculated as 8.4 and 2.5 Umg-1, respectively. The primary anti-PSA was conjugated to a magnetic bead and used as PSA-specific capturing. Then, the secondary anti-PSA was grafted to the rGMOF. In the presence of antigen, an immuno-sandwich was formed between the conjugations mentioned above. Afterward, AuNRs were etched by rGMOF, and the related spectrum was recordedin the wavelength range 350 to 900nm.By progressing the etching procedure, the longitudinal LSPR peak of AuNRs was gradually blue-shifted with a linear correlation with the PSA concentration from 0.1pgmL-1 to 100ngmL-1. The detection limit was 0.09pgmL-1. Theproposed immunosensor was successfully employed to determine PSA levels in real samples. Since the obtained results showed an excellent correlation with those acquired by the chemiluminescence gold standard method, it has the potential for PSA determination in clinical assays.

A facile integrated microfluidic chip based on Chitosan-Gold Nanoparticles-Anchored Three-Dimensional graphene fiber film for monitoring prostate specific antigen

Microfluidic electrochemical sensors are emerging as favorable platforms for rapid and precise detection of disease markers relying on their superiority of miniaturization, low electrolyte consumption, high precision and integration. Herein, an efficient and facile integrated microfluidic sensor with three-dimensional graphene fiber film/chitosan-gold nanoparticles (3D GF/CS-Au NPs) micro-nano composites as sensing interface was developed for the analysis of prostate specific antigen (PSA). The GF with 3D network structures modified by large amounts of CS-Au nanoparticles could facilitate the enhancement of electrochemical signals. The electrodes and microchannel were simply assembled and encapsulated by bolts, which made the microfluidic chip had excellent portability and operability. On the basis of this new microfluidic device and the 3D GF/CS-Au NPs composites, a sensitive determination of PSA could be realized with a low detection limit of 0.51 pg/mL and a wide response range from 0.001 − 200 ng/mL. Moreover, the proposed biosensor was further used to detect analytes in human blood samples, showing the satisfactory results. This novel microfluidic electrochemical immunosensor demonstrated superior performance for PSA detection, holding potential application in clinical diagnosis and personalized healthcare.

Prostate-Specific Antigen Monitoring Using Nano Zinc(II) Metal-Organic Framework-Based Optical Biosensor.

The prostate-specific antigen (PSA) is an important cancer biomarker that is commonly utilized in the diagnosis of prostate cancer. The development of a PSA determination technique that is rapid, simple, and inexpensive, in addition to highly accurate, sensitive, and selective, remains a formidable obstacle. In this study, we developed a practical biosensor based on Zn(II) metal-organic framework nanoparticles (Zn-MOFs-NPs). Many spectroscopic and microanalytical tools are used to determine the structure, morphology, and physicochemical properties of the prepared MOF. According to the results, Zn-MOFs-NPs are sensitive to PSA, selective to an extremely greater extent, and stable in terms of chemical composition. Furthermore, the Zn-MOFs-NPs did not exhibit any interferences from other common analytes that might cause interference. The detection limit for PSA was calculated and was 0.145 fg/mL throughout a wide linear concentration range (0.1 fg/mL-20 pg/mL). Zn-MOFs-NPs were successfully used as a growing biosensor for the monitoring and measurement of PSA in biological real samples.

Disposable Amperometric Label-Free Immunosensor on Chitosan-Graphene-Modified Patterned ITO Electrodes for Prostate Specific Antigen.

A facile and highly sensitive determination of prostate-specific antigen (PSA) is of great significance for the early diagnosis, monitoring and prognosis of prostate cancer. In this work, a disposable and label-free electrochemical immunosensing platform was demonstrated based on chitosan–graphene-modified indium tin oxide (ITO) electrode, which enables sensitive amperometric determination of PSA. Chitosan (CS) modified reduced graphene oxide (rGO) nanocomposite (CS–rGO) was easily synthesized by the chemical reduction of graphene oxide (GO) using CS as a dispersant and biofunctionalizing agent. When CS–rGO was modified on the patterned ITO, CS offered high biocompatibility and reactive groups for the immobilization of recognition antibodies and rGO acted as a transduction element and enhancer to improve the electronic conductivity and stability of the CS–rGO composite film. The affinity-based biosensing interface was constructed by covalent immobilization of a specific polyclonal anti-PSA antibody (Ab) on the amino-enriched electrode surface via a facile glutaraldehyde (GA) cross-linking method, which was followed by the use of bovine serum albumin to block the non-specific sites. The immunosensor allowed the detection of PSA in a wide range from 1 to 5 ng mL−1 with a low limit of detection of 0.8 pg mL−1. This sensor also exhibited high selectivity, reproducibility, and good storage stability. The application of the prepared immunosensor was successfully validated by measuring PSA in spiked human serum samples.