Enhanced detection sensitivity of prostate-specific antigen via PSA-conjugated gold nanoparticles based on localized surface plasmon resonance: GNP-coated anti-PSA/LSPR as a novel approach for the identification of prostate anomalies

• Published in: Cancer gene therapy 2016-10, Vol.23 (10), p.365-369
• Main Authors: Jazayeri, M H, Amani, H, Pourfatollah, A A, Avan, A, Ferns, G A, Pazoki-Toroudi, H
• Format: Article
• Language: English
• Subjects: 101/1; 101/28; 631/1647/767/70; 631/67/589/466; Absorption spectroscopy; Analysis; Antigens; Biomedical and Life Sciences; Biomedicine; Cancer; Colloids - chemistry; Diagnosis; Early Detection of Cancer; Gene Expression; Gene Therapy; Gold - chemistry; Humans; Light scattering; Male; Metal Nanoparticles - chemistry; Microscopy, Electron, Transmission; Nanoparticles; original-article; Particle Size; Prostate - pathology; Prostate cancer; Prostate-specific antigen; Prostate-Specific Antigen - blood; Prostatic Neoplasms - diagnosis; Prostatic Neoplasms - drug therapy; Size distribution; Spectrophotometry, Ultraviolet; Surface Plasmon Resonance; Transmission electron microscopy
• ISSN: 0929-1903; 1476-5500
• DOI: 10.1038/cgt.2016.42

Prostate-specific antigen (PSA) is used to screen for prostate disease, although it has several limitations in its application as an organ-specific or cancer-specific marker. Furthermore, a highly specific/sensitive and/or label-free identification of PSA still remains a challenge in the diagnosis of prostate anomalies. We aimed to develop a gold nanoparticle (GNP)-conjugated anti-PSA antibody-based localized surface plasmon resonance (LSPR) as a novel approach to detect prostatic disease. A total of 25 nm colloidal gold particles were prepared followed by conjugation with anti-PSA pAb (GNPs–PSA pAb). LSPR was used to monitor the absorption changes of the aggregation of the particles. The size, shape and stability of the GNP-anti-PSA were evaluated by dynamic light scattering transmission electron microscopy (TEM) and zetasizer. The GNPs-conjugated PSA-pAb was successfully synthesized and subsequently characterized using ultraviolet absorption spectroscopy and TEM to determine the size distribution, crystallinity and stability of the particles (for example, stability of GNP: 443 mV). To increase the stability of the particles, we pegylated GNPs using an N -(3-dimethylaminopropyl)- N *-ethylcarbodiimide hydrochloride (EDC)/ N -hydroxylsuccinimide (NHS) linker (for example, stability of GNP after pegylation: 272 mV). We found a significant increase in the absorbance and intensity of the particles with extinction peak at 545/2 nm, which was shifted by ~1 nm after conjugation. To illustrate the potential of the GNPs–PSA pAb to bind specifically to PSA, LSPR was used. We found that the extinction peak shifted 3 nm for a solution of 100 n M unlabeled antigen. In summary, we have established a novel approach for improving the efficacy/sensitivity of PSA in the assessment of prostate disease, supporting further investigation on the diagnostic value of GNP-conjugated anti-PSA/LSPR for the detection of prostate cancer.