Detection Of Prostate Specific Antigen 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).

Noninferiority of Hypofractionated vs Conventional Postprostatectomy Radiotherapy for Genitourinary and Gastrointestinal Symptoms

No prior trial has compared hypofractionated postprostatectomy radiotherapy (HYPORT) to conventionally fractionated postprostatectomy (COPORT) in patients primarily treated with prostatectomy. To determine if HYPORT is noninferior to COPORT for patient-reported genitourinary (GU) and gastrointestinal (GI) symptoms at 2 years. In this phase 3 randomized clinical trial, patients with a detectable prostate-specific antigen (PSA; ≥0.1 ng/mL) postprostatectomy with pT2/3pNX/0 disease or an undetectable PSA (<0.1 ng/mL) with either pT3 disease or pT2 disease with a positive surgical margin were recruited from 93 academic, community-based, and tertiary medical sites in the US and Canada. Between June 2017 and July 2018, a total of 296 patients were randomized. Data were analyzed in December 2020, with additional analyses occurring after as needed. Patients were randomized to receive 62.5 Gy in 25 fractions (HYPORT) or 66.6 Gy in 37 fractions (COPORT). The coprimary end points were the 2-year change in score from baseline for the bowel and urinary domains of the Expanded Prostate Cancer Composite Index questionnaire. Secondary objectives were to compare between arms freedom from biochemical failure, time to progression, local failure, regional failure, salvage therapy, distant metastasis, prostate cancer-specific survival, overall survival, and adverse events. Of the 296 patients randomized (median [range] age, 65 [44-81] years; 100% male), 144 received HYPORT and 152 received COPORT. At the end of RT, the mean GU change scores among those in the HYPORT and COPORT arms were neither clinically significant nor different in statistical significance and remained so at 6 and 12 months. The mean (SD) GI change scores for HYPORT and COPORT were both clinically significant and different in statistical significance at the end of RT (-15.52 [18.43] and -7.06 [12.78], respectively; P < .001). However, the clinically and statistically significant differences in HYPORT and COPORT mean GI change scores were resolved at 6 and 12 months. The 24-month differences in mean GU and GI change scores for HYPORT were noninferior to COPORT using noninferiority margins of -5 and -6, respectively, rejecting the null hypothesis of inferiority (mean [SD] GU score: HYPORT, -5.01 [15.10] and COPORT, -4.07 [14.67]; P = .005; mean [SD] GI score: HYPORT, -4.17 [10.97] and COPORT, -1.41 [8.32]; P = .02). With a median follow-up for censored patients of 2.1 years, there was no difference between HYPORT vs COPORT for biochemical failure, defined as a PSA of 0.4 ng/mL or higher and rising (2-year rate, 12% vs 8%; P = .28). In this randomized clinical trial, HYPORT was associated with greater patient-reported GI toxic effects compared with COPORT at the completion of RT, but both groups recovered to baseline levels within 6 months. At 2 years, HYPORT was noninferior to COPORT in terms of patient-reported GU or GI toxic effects. HYPORT is a new acceptable practice standard for patients receiving postprostatectomy radiotherapy. ClinicalTrials.gov Identifier: NCT03274687.

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.

Synergistic optical enhancement of Au/AgNTs@CDs immunoprobe with tips and gaps for SERS/FL dual mode detection of PSA

Robust and highly sensitive nano-optical immunoprobes have emerged as powerful tools to improve the accuracy and sensitivity of early disease diagnosis. This work develops a pentagonal gold/silver nanotube @ carbon dot (Au/AgNTs@CDs) SERS/FL dual-mode immunoprobe for detecting prostate-specific antigen (PSA) in serum by subtly integrating small gaps and branch tip structures. Benefiting from the synergistic optical enhancement of tips and small gaps, this novel rough porous Au/Ag nanotube exhibits larger specific surface area and more active sites as well as remarkable stability. The optical enhancement brought by the innovative structural design increases the detection sensitivity of the immunoprobe to the state of the art. To the best of our knowledge, the limit of detection is an order of magnitude lower than reported in the literature in SERS and fluorescence modes, respectively. Furthermore, both modes exhibit excellent robustness and specificity. Therefore, the design of this immunoprobe provides a new perspective and broad application prospects for improving the sensitivity and accuracy of clinical diagnosis.

A highly sensitive ratiometric electrochemical aptasensor for prostate specific antigen detection based on toehold-mediated strand displacement reaction

In this work, a novel ratiometric electrochemical aptasensor was designed for prostate specific antigen (PSA) detection based on toehold-mediated strand displacement reaction (TMSDR). For PSA detection, PSA could bind with the aptamer sequence in hairpin probe 1 (HP1), and HP1/PSA complex was obtained. Then, in the presence of S3 DNA, HP1/PSA could trigger two TMSDR processes by hybridizing with Fc-S2/S1 double-stranded DNA, which would generate a large amount of Fc-S2 and recycle HP1/PSA. This enabled the hybridization of Fc-S2 with methylene blue labeled thiolated hairpin probe 2 (MB-HP2) immobilized on the electrode surface, causing MB molecules away from the electrode and Fc close to the electrode. Thus, with the increasing PSA concentrations, the current of MB (IMB) decreased and the current of Fc (IFc) increased. The ratio of IFc/IMB was shown to be linear with the logarithm of PSA concentration from 1 pg mL−1 to 100 ng mL−1, with a detection limit of 0.28 pg mL−1. In addition, the aptasensor had good specificity, reproducibility, repeatability, and stability for PSA detection, and was successfully applied to spiked diluted human serum samples.

Carbon quantum dots(CQDs)-sensitized CdS/CuInS2 heterojunction as a photoelectrochemical biosensing platform for highly sensitive detection of prostate-specific antigen

Sensitive and quantitative detection of prostate-specific antigen (PSA) has been determined to be indispensable for clinical diagnostics of prostate cancer, whereas such detection is quite challenging due to the extremely low concentration of biomarkers in human serum samples. In this study, a photoelectrochemical (PEC) sensor was effectively developed for the high-sensitivity analysis of prostate-specific antigen (PSA) using a signal amplification method utilizing sensitized carbon quantum dots (CQDs). In this experiment, cadmium sulfide quantum dots were employed as the substrate materials, and indium copper sulfide quantum dots were loaded on their surfaces. Moreover, the efficient matching of energy levels in these two materials contributed to the generation of photocurrents. The aforementioned heterojunction semiconductor QDs were thus combined with CQDs to produce CQDs on their surfaces. As a result of the presence of CQDs, the ability of heterojunction materials to absorb light was remarkably enhanced, increasing the photocurrent by over ten times. Consequently, in this study, CQDs were combined with PEC sensors, and the developed PEC biosensors exhibited excellent optical performance, sensitivity, repeatability, and stability. The results obtained from the analysis of actual samples were satisfactory and have promising application prospects.

A Label-free Electrochemical Immunosensor Based on Gold Nanoparticles-poly(ferriporphyrin-co-acrylamide)-reduced Graphene Oxide and the Application in Prostate Specific Antigen Detection

A Label-free Electrochemical Immunosensor Based on Gold Nanoparticles-poly(ferriporphyrin-co-acrylamide)-reduced Graphene Oxide and the Application in Prostate Specific Antigen Detection

Merging Lateral Flow Immunoassay with Electroanalysis as a Novel Sensing Platform: Prostate Specific Antigen Detection as Case of Study.

The COVID-19 pandemic highlighted lateral flow immunoassay (LFIA) strips as the most known point-of-care (POC) devices enabling rapid and easy detection of relevant biomarkers by nonspecialists. However, these diagnostic tests are usually associated with the qualitative detection of the biomarker of interest. Alternatively, electrochemical-based diagnostics, especially known for diabetes care, enable quantitative determination of biomarkers. From an analytical point perspective, the combination of the two approaches might represent a step forward for the POC world: in fact, electrochemical transduction is attractive to be integrated into LFIA strips due to its simplicity, high sensitivity, fast signal generation, and cost effectiveness. In this work, a LFIA strip has been combined with an electrochemical transduction, yielding an electrochemical LFIA (eLFIA). As a proof-of-concept method, the detection of prostate-specific antigen has been carried out by combining a printed-electrochemical strip with the traditional LFIA tests. The electrochemical detection has been based on the measurement of Au ions produced from the dissolution of the gold nanoparticles previously captured on the test line. The analytical performances obtained at LFIA and eLFIA were compared, highlighting how the use of differential pulse voltammetry allowed for a lower detection limit (2.5-fold), respectively, 0.38 and 0.15 ng/mL, but increasing the time of analysis. Although the correlation between the two architectures confirmed the satisfactory agreement of outputs, this technical note has been thought to provide the reader a fair statement with regard to the strength and drawbacks about combining the two (apparently) competitor devices in a diagnostics field, namely, LFIA and electrochemical strips.

Validity of Partner Reports of Recent Condomless Sex.

Prostate-specific antigen (PSA), a biomarker of vaginal semen exposure, is less susceptible to bias than self-reported condom use behaviors. We examined the agreement of self-reported recent condomless sex (RCS) within couples and how these reports related to PSA detection. We analyzed data from a study conducted in Vietnam, 2017 to 2020, of 500 different-sex couples using condoms and no other contraceptive method to prevent pregnancy for 6 months. We assessed enrollment and 6-month data from vaginal swabs and questionnaires from both partners. We calculated Prevalence-Adjusted Bias-Adjusted Kappa (PABAK) to evaluate agreement of men's and women's reports. Among couples with detected PSA, we assessed partner concordance of RCS reporting. At enrollment (n = 499), 79.8% of couples reported no RCS, 16.4% reported RCS, and 3.8% had partner-discordant reports (PABAK, 0.93; 95% confidence interval, 0.91-0.97). At 6 months (n = 472), 91.7% reported no RCS, 5.7% reported RCS, and 2.5% had partner-discordant reports (PABAK, 0.98; 95% confidence interval, 0.96-1.0). Among couples with detected PSA at baseline (11%, n = 55), 36% reported no RCS, 55% reported RCS, and 6% had discordant reports; at 6 months (6.6%, n = 31), 58% reported no RCS, 35% reported RCS, and 3% had discordant reports. We observed high agreement regarding condomless sex within couples in a population using condoms as contraception in Vietnam; however, a high proportion of couples with detected PSA had both partners reporting no RCS, indicating that concordant reporting of no RCS does not indicate lack of semen exposure.

Futuristic Silicon Photonic Biosensor with Nanomaterial Enhancement for PSA Detection

This article describes a novel electrochemical on-chip biosensor that utilises the anti-PSA antibody (Ab) and silver nanoparticles (AgNPs) to enhance the sensing and detection capability of the prostate-specific antigen (PSA) in the blood. The AgNPs are prepared, characterised, and applied to a silicon photonic on-chip biosensing receptor platform designed to enhance the accurate detection of PSA. The AgNPs were synthesised by a chemical reduction method using silver nitrate (AgNO3) as the precursor. Transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersion X-ray spectroscopy (EDS), small angle X-ray scattering (SAXS), X-ray diffraction (XRD), and light microscopy were among the methods used in the characterisation and analysis of the AgNPs. Each stage of the immunosensor fabrication was characterised using cyclic voltammetry. The proposed immunosensor was applied in the detection of PSA, a prostate cancer biomarker, with a high sensitivity and a limit of detection of 0.17 ng/mL over a linear concentration range of 2.5 to 11.0 ng/mL. The immunosensor displayed good stability and was selective in the presence of interfering species like immunoglobulin (Ig) in human serum, ascorbic acid (AA), and diclofenac (Dic). The detectivity and sensitivity are significantly higher than previous reports on similar or related technologies.

Development of gold nanospikes-modified quartz crystal microbalance biosensor for prostate specific antigen detection

Prostate-specific antigen (PSA) screening is vital for the early detection and assessment of prostate cancer treatment efficacy. Integrating nanotechnology into biosensor development allows for targeted biomarker detection. In this study, we present the fabrication of gold nanospikes (AuNS) structures on a quartz crystal microbalance (QCM) using the pulse current electrodeposition (PCD) technique. By varying the duty cycles of PCD, we achieved the desired nanostructure. The characteristics of the AuNS-modified QCM electrode were thoroughly investigated using various micro-structural characterization techniques such as x-ray diffraction (XRD), field emission scanning electron microscope (FESEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). Prior to biomolecule immobilization, each chemical treatment was verified through contact angle and FT-IR analyses. The performance of the developed QCM biosensor was evaluated using PSA at various concentrations. The results revealed that the frequency variation of the QCM biosensor was directly proportional to the PSA concentration. Notably, the AuNS-modified QCM biosensor exhibited the highest frequency shift at a 20 % duty cycle, demonstrating a linear detection range of 0.1–100 ng mL−1 and a limit of detection (LOD) of 24 pg mL−1. The developed QCM biosensor significantly enhances detection efficiency by increasing the number of binding sites for biomolecules through an enlarged surface area. The demonstrated sensitivity of the AuNS-modified QCM biosensor indicates its potential to address the increasing demand for early diagnosis and screening in healthcare systems. This innovative biosensor technology holds promise for improving prostate cancer detection and has broader implications for the development of highly sensitive biosensors for various biomarkers.

Construction of Multi-Mode Photoelectrochemical Immunoassays for Accurate Detection of Cancer Markers: Assisted with MOF-Confined Plasmonic Nanozyme.

In clinical diagnostics, sensitive and accurate biomarker monitoring is greatly challenged by the limitations of false positive/negative errors in single-modal photoelectrochemical analysis. Herein, we propose a multimode immunoassay by integrating photoelectrochemical, colorimetric, and photothermal imaging analysis into one electrode. The immunosensors could simultaneously achieve three detection modes at one electrode, which provided a new pathway for the accurate detection of the target prostate-specific antigen (PSA) and circumvented false-positive or negative errors during the detection process. To this end, an integrated multifunctional chip (TiO2/ZIF-8/Cu(II)) was first constructed via in situ embedding of Cu(II) in the Metal-organic framework growth process. Then, an alkaline phosphatase-labeled magnetic probe was designed to achieve split-type detection for PSA. In a sodium thiophosphate solution, the in situ generated H2S could react with Cu(II) to form small-size CuS due to the nanoconfinement of ZIF-8 and thus result in the formation of p-n heterojunctions (TiO2/ZIF-8/CuS). The TiO2/ZIF-8/CuS could efficiently improve the light-harvesting ability and facilitate the charge separation efficiency, thus finally resulting in an increased photocurrent in the PEC mode. Furthermore, by constructing the portable colorimetric and photothermal sensors based on the Arduino microcontroller and photothermal imager, the TiO2/ZIF-8/CuS also provided point-of-care and visual detection modes, as the in situ-formed CuS exhibited peroxidase-mimicking activity and outstanding photothermal properties. The work had important prospects for establishing multimode immunoassays for the accurate detection of cancer markers in early disease diagnosis.

SERS-Temperature Dual-Mode T-type Lateral Flow Strip for Accurate Detection of Free and Total Prostate-Specific Antigens in Blood.

Accurate point-of-care (POC) analysis of cancer markers is the essence in the comprehensive early screening and treatment of cancer. Dual-mode synchronous detection is one of the effective approaches to reduce the probability of false negatives or false positives. As a result, this can greatly improve the accuracy of diagnosis. In this work, a surface-enhanced Raman scattering (SERS)-temperature dual-mode T-type lateral flow strip was fabricated to direct and simultaneous POC detection of total and free prostate-specific antigens (t-PSA and f-PSA) in blood. With the advantage of high stability of T-type lateral flow strip and simultaneous acquirement of assay results for t-PSA and f:t PSA ratio, the proposed method has high accuracy in the diagnosis of prostate cancer, especially in the diagnostic gray zone between 4.0 and 10.0 ng/mL. The SERS-temperature dual-signal has a good linear correlation with either f-PSA or t-PSA. To evaluate the clinical diagnostic performance of the proposed method, spiked human serum samples and the whole blood sample were analyzed. The assay results showed good recovery, and compared with traditional electrochemiluminescence immunoassay (ECLIA) method (t-PSA: 43.151; f/t ratio: 0.08), the results obtained by the proposed method were similar (t-PSA: 40.15 (SERS), 36.21 (temperature); f/t ratio: 0.08 (SERS), 0.08 (temperature), but the detection time (15 min) and cost ($0.05) had been greatly reduced. Therefore, the proposed SERS-temperature synchronous dual-mode T-type lateral flow strip has a strong application potential in the field of accurate large-scale diagnostics of prostate cancer on-site by simultaneous POC detection of t-PSA and f-PSA in blood.

Bio-conjugated carbon dots for the bimodal detection of prostate cancer biomarkers via sandwich fluorescence and electrochemical immunoassays.

Bimodal detection facilitates the accurate and reliable detection of cancer biomarkers, which can assist in the early diagnosis of cancer. Herein, S-doped carbon dots (OCDs) with a size of 3 nm and blue emission were synthesized by the hydrothermal treatment of onion extract. The S-doped carbon dots were bioconjugated with an antibody (OCDs@PSAAbHRP) to design a nanoprobe for the detection of prostate specific antigen (PSA), an important serum based prostate cancer biomarker. The detection probe enabled the biomodal assay of PSA via fluorescence immunoassay (FIA) and electrochemical immunoassay (ECIA). In both assays, polyethylenimine stabilized polyaniline nanoparticles (PNPs) were used as the immobilization matrix, which played a major role in widening the linear range of biosensors (0.1 to 100 ng ml-1 for ECIA and 5 to 120 ng ml-1 for FIA). Paper-based and smartphone-integrated fluorescence immuno-array developed using the OCDs@PSAAbHRP detection probe provided cost-effective and rapid detection, while the electrochemical immunoassay provided a high sensitivity (7.8 μA ng-1 ml-1 cm-2) and low detection limit (38 pg ml-1) for PSA detection. The role of OCDs in enhancing the sensor performance was deciphered by carrying out detailed electrochemical studies with HRP enzyme-loaded OCDs. The biosensor was used to detect PSA in human blood serum samples and the results were consistent with conventional techniques. Owing to its analytical properties coupled with simplicity, cost-effectiveness, and portability, the bimodal sensor system has potential for application in clinical analysis.

Plasmonic biochips with enhanced stability in harsh environments for the sensitive detection of prostate-specific antigen.

Hollow and porous plasmonic nanomaterials have been demonstrated for highly sensitive biosensing applications due to their distinctive optical properties. Immunosensors, which rely on antibody-antigen interactions, are essential constituents of diverse biosensing platforms owing to their exceptional binding affinity and selectivity. The majority of immunosensors and conventional bioassays needs special storage conditions and cold chain systems for transportation. Prostate-specific antigen (PSA), a serine protease, is widely employed in the diagnosis of prostate cancer. In this study, we present the successful utilization of a biopolymer-preserved plasmonic biosensor with improved environmental stability for the sensitive detection of PSA. The preserved plasmonic biosensors exhibited sustained sensitivity in the detection of PSA, achieving a limit of detection of 10 pg mL-1. Furthermore, these biosensors exhibited remarkable stability at elevated temperatures for one week.

Antibody fluorescein-doped silica nanobioconjugates for the ultrasensitive detection of prostate-specific antigen

Fluorescein-doped silica nanoparticles were bioconjugated with anti-prostate-specific antigen polyclonal antibodies for fluorescence immunoassay and the detection of prostate-specific antigen in fg mL−1 detection limits.

The Omission of Upfront Treatment Intensification Does Not Adversely Affect Oncological Outcomes in a Subset of Castration-Highly Sensitive Metastatic Prostate Cancer.

In patients with metastatic castration-sensitive prostate cancer (mCSPC), upfront treatment intensification with the addition of new hormonal agents and/or docetaxel to androgen deprivation therapy (ADT) is recommended. However, this modality is potentially excessive in a subset of these patients. This study aimed to identify patients who may be eligible to omit upfront treatment intensification. Patients with mCSPC who underwent ADT were enrolled. The association between undetectable prostate-specific antigen (PSA) (<0.2 ng/ml) after ADT initiation and overall or castration-resistance-free survival was evaluated. Ninety-seven out of the 242 enrolled patients had low-risk and/or low-volume cancer and were further analyzed. Of these, 45 (46.4%) patients achieved undetectable PSA. The median follow-up period after ADT initiation was 70 months. The median overall survival among patients with undetectable PSA was quite long, reaching 226 months and significantly longer than that among patients with detectable PSA [71 months, hazard ratio (HR)=0.27, 95% confidence interval (CI)=0.15-0.49, p<0.001]. Time to development of castration-resistance was also long and significantly longer in the undetectable PSA group than that in the detectable PSA group (median: 124 vs. 17 months, HR=0.20, 95% CI=0.12-0.34, p<0.001). Patients with low-risk and/or low-volume mCSPC showed long-term survival when undetectable PSA was achieved during conventional ADT. In these patients, skipping upfront treatment intensification does not seem to negatively impact survival.

Single-molecule microfluidic assay for prostate-specific antigen based on magnetic beads and upconversion nanoparticles.

Early-stage diagnosis of prostatic carcinoma is essential for successful treatment and, thus, significant prognosis improvement. In laboratory practice, the standard non-invasive diagnostic approach is the immunochemical detection of the associated biomarker, prostate-specific antigen (PSA). Ultrasensitive detection of PSA is essential for both diagnostic and recurrence monitoring purposes. To achieve exceptional sensitivity, we have developed a microfluidic device with a flow-through cell for single-molecule analysis using photon-upconversion nanoparticles (UCNPs) as a detection label. For this purpose, magnetic microparticles (MBs) were first optimized for the capture and preconcentration of PSA and then used to implement a bead-based upconversion-linked immunoassay (ULISA) in the microfluidic device. The digital readout based on counting single nanoparticle-labeled PSA molecules on MBs enabled a detection limit of 1.04 pg mL-1 (36 fM) in 50% fetal bovine serum, which is an 11-fold improvement over the respective analog MB-based ULISA. The microfluidic technique conferred several other advantages, such as easy implementation and the potential for achieving high-throughput analysis. Finally, it was proven that the microfluidic setup is suitable for clinical sample analysis, showing a good correlation with a reference electrochemiluminescence assay (recovery rates between 97% and 105%).

Enrichment of prostate-specific antigen using magnetic-silica antibody nanobioconjugates and fluorescence detection

Herein, we report the development of the immunosensor for the detection of prostate-specific antigen (PSA). The immunosensor platform was based on the immunometric sandwich protocol, using magnetic-silica nanoparticles to capture...

Electrolyte-gated amorphous IGZO transistors with extended gates for prostate-specific antigen detection.

The prostate-specific antigen (PSA) test is considered an important way for preoperative diagnosis and accurate screening of prostate cancer. Current antigen detection methods, including radioimmunoassay, enzyme-linked immunosorbent assay and microfluidic electrochemical detection, feature expensive equipment, long testing time and poor stability. Here, we propose a portable biosensor composed of electrolyte-gated amorphous indium gallium zinc oxide (a-IGZO) transistors with an extended gate, which can achieve real-time, instant PSA detection at a low operating voltage (<2 V) owing to the liquid-free ionic conductive elastomer (ICE) serving as the gate dielectric. The electric double layer (EDL) capacitance in ICE enhances the accumulation of carriers in the IGZO channel, leading to strong gate modulation, which enables the IGZO transistor to have a small subthreshold swing (<0.5 V dec-1) and a high on-state current (∼4 × 10-4 A). The separate, biodegradable, and pluggable sensing pad, serving as an extended gate connected to the IGZO transistor, prevents contamination and depletion arising from direct contact with biomolecular buffers, enabling the IGZO transistor to maintain superior electronic performance for at least six months. The threshold voltage and channel current of the transistor exhibit excellent linear response to PSA molecule concentrations across five orders of magnitude ranging from 1 fg mL-1 to 10 pg mL-1, with a detection limit of 400 ag mL-1 and a detection time of ∼5.1 s. The fabricated biosensors offer a point-of-care system for antigen detection, attesting the feasibility of the electrolyte-gated transistors in clinical screening, healthcare diagnostics and biological management.