Biocompatible Osmium Telluride-Polypyrrole Nanocomposite Material: Application in Prostate Specific Antigen Immunosensing

Prostate cancer is a dominant global threat to society. It affects nearly 4000 men in South Africa annually, making it the second most threatening cancerous disease after lung cancer. A potential serological biomarker to monitor early diagnosis of prostate cancer is prostate specific antigen (PSA). We used the PSA biomarker in our work to develop an extremely sensitive electrochemical immunosensor to achieve low detection limits. The fabrication steps followed with the combination of thioglycolic acid capped osmium telluride quantum dots (TGA-OsTe2QD)-polypyrrole (PPy) nanocomposite and prostate specific antigen modified on a glassy carbon electrode. The UV-Vis signatures of TGA-OsTe2QD-PPy showed an absorption band at 262 nm which is attributed to the PPy and TGA-OsTe2QD composite. This band corresponds to the energy band gap of 4.4 and 5.4 eV. The CV responses of BSA|Ab|TGA-OsTe2QD|PPy|GCE modified electrode to prostate specific antigen (PSA) was studied within a range of 0–16 ng/mL PSA that was linear, herein referred to as liner range (LR), which produced a limit of detection (LOD) value of 0.36 ng/mL PSA. The values of the immunosensor’s calibration parameters (LR and LOD) make them suitable for real sample application, due to their coverage of the PSA concentration range (0–14 ng/mL) that is of clinical importance.

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Improved reverse transcriptase–polymerase chain reaction protocol with exogenous internal competitive control for prostate-specific antigen mRNA in blood and bone marrow

Clinical Chemistry ◽

10.1093/clinchem/43.3.443 ◽

1997 ◽

Vol 43 (3) ◽

pp. 443-452 ◽

Cited By ~ 28

Author(s):

Eva Corey ◽

Edward W Arfman ◽

Alvin Y Liu ◽

Robert L Vessella

Keyword(s):

Prostate Cancer ◽

Bone Marrow ◽

Reverse Transcriptase ◽

Prostate Specific Antigen ◽

Mononuclear Cells ◽

Limit Of Detection ◽

Specific Antigen ◽

High Specificity ◽

Significant Advance ◽

Peripheral Blood Mononuclear

Abstract The possibility of improving diagnosis of micrometastases from prostate cancer by further enhancing the detection of prostate-specific antigen-producing cells in circulation is being evaluated. We have developed a reverse transcriptase-PCR protocol with the desirable characteristics of low limit of detection, high specificity, reproducibility of response, and ease of performance. Among the procedural alterations that have contributed to these improvements are longer PCR primers, a two-step amplification cycle, and hot-start PCR. We have lowered the limit of detection to one LNCaP prostate-cancer cell in 108 peripheral blood mononuclear cells, and samples of blood and bone marrow from healthy donors have yielded no false positives. Because PCR procedures frequently exhibit tube-to-tube variability, we have incorporated a set of internal and external controls into the protocol—a significant advance in assuring assay reliability.

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Ultrasensitive time-resolved immunofluorometric assay of prostate-specific antigen in serum and preliminary clinical studies

Clinical Chemistry ◽

10.1093/clinchem/39.10.2108 ◽

1993 ◽

Vol 39 (10) ◽

pp. 2108-2114 ◽

Cited By ~ 79

Author(s):

H Yu ◽

E P Diamandis

Keyword(s):

Prostate Cancer ◽

Alkaline Phosphatase ◽

Radical Prostatectomy ◽

Early Detection ◽

Prostate Specific Antigen ◽

Limit Of Detection ◽

Specific Antigen ◽

Clinical Applications ◽

Time Resolved ◽

Extreme Sensitivity

Abstract We developed an ultrasensitive method for measuring prostate-specific antigen (PSA) in serum. The assay includes a capture monoclonal anti-PSA antibody coated to microtiter wells, a biotinylated rabbit polyclonal detection antibody, and alkaline phosphatase (ALP)-labeled streptavidin. The activity of ALP is measured with the substrate diflunisal phosphate; the released diflunisal forms highly fluorescent complexes with Tb(3+)-EDTA that are quantified with microsecond time-resolved fluorometry. The assay is precise and accurate and correlates well with the established Hybritech Tandem-PSA kit. Its distinguishing feature is extreme sensitivity (lowest limit of detection is 0.002 micrograms/L or 2 x 10(6) PSA molecules per assay). This is the most sensitive PSA assay reported thus far; we used it to quantify PSA in patients who had undergone radical prostatectomy. Many patients had < 0.01 micrograms/L PSA in their serum. This method could have important clinical applications in postsurgical early detection of relapse or residual prostate cancer, as recently suggested in the literature (Clin Chem 1992;38:1930-2).

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Utility of a Fifth-Generation Ultrasensitive Prostate-Specific Antigen Assay for Monitoring Prostate Cancer Patients after Radical Prostatectomy with 3 Years of Follow-Up

Clinical Chemistry ◽

10.1093/clinchem/hvaa176 ◽

2020 ◽

Vol 66 (10) ◽

pp. 1329-1338

Author(s):

Annie H Ren ◽

Antoninus Soosaipillai ◽

Anu Mathew ◽

Galina Nikolenko ◽

Laukik Sardesai ◽

...

Keyword(s):

Prostate Cancer ◽

Radical Prostatectomy ◽

Prostate Specific Antigen ◽

Limit Of Detection ◽

Specific Antigen ◽

Serum Samples ◽

Psa Kinetics ◽

Fifth Generation ◽

Low Concentrations ◽

Significant Difference

Abstract Background We investigated an ultrasensitive prostate-specific antigen (uPSA) immunoassay (MesoScale; lower limit of detection (LLD) of 0.0035 pg/mL) to monitor patients with prostate cancer (PCa) following radical prostatectomy (RP) and to examine whether changes in PSA in the conventionally undetectable range (<1 pg/mL) can predict biochemical relapse (BCR). Methods We measured uPSA in serial serum samples (N = 100) collected from 20 RP cases with a third-generation ELISA (LLD of 1 pg/mL) and the fifth-generation MesoScale assay. We analyzed the PSA nadir changes to classify patients into BCR or non-BCR groups, observed the trends in PSA kinetics, and associated BCR status with clinicohistopathological features. Results The ELISA could quantify PSA in only 38% of the RP samples, detecting BCR in 7 of 20 patients with PCa. The MesoScale assay quantified PSA in all samples, showing 8 of 20 patients with BCR. However, there was no significant difference between the median time to BCR detection based on ELISA (1016 days) compared with MesoScale data (949 days). Gleason scores were higher in the BCR groups compared with non-BCR. There was no significant difference for other clinicohistopathological parameters. Conclusions The uPSA MesoScale technology could track miniscule changes in serum PSA in the range of 0.003–1 pg/mL in all RP cases. However, PSA kinetics and nadir at concentrations <2 pg/mL fluctuated, and increases below this range could not reliably suggest signs of BCR. Instead, ultrasensitive fifth-generation PSA assays may hold clinical potential for measuring the low concentrations of PSA in women for various medical contexts.

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