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

Abstract

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 nM 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.

Recent Advances in the Generation of Antibody–Nanomaterial Conjugates

“…However, in this study, there were limited data on the number of antibodies per nanoparticles; one limitation of this technique through using random amide coupling chemistry is the inability to control the number and presentation of coupled antibodies on the surface of the GNPs. [32] A study performed by Kim et al utilized saliva as a biomarker medium in an attempt to diagnose Alzheimer's disease (AD). Development of AD involves aggregation of β-amyloid peptide in the cerebrum resulting in loss of intellectual abilities.…”

Nanoparticles as Theranostic Vehicles in Experimental and Clinical Applications—Focus on Prostate and Breast Cancer

“…So far though, this technique has only been used occasionally in PCa and BC NP applications. Since EM is not considered to be an imaging technique possible to use in theranostic contexts, its value lies instead in in vitro and ex vivo analyses, as mentioned above, or during the production process of the NPs in order to be able to characterize them properly [401,402,403,404,405,406,407,408]. …”

Surface Plasmon Resonance or Biocompatibility—Key Properties for Determining the Applicability of Noble Metal Nanoparticles

“…AuNPs and LSPR-based biosensing approach has been recently explored as novel tool for the early diagnosis of prostate disease. Jazayeri et al [ 46 ] established a novel approach for improving the efficacy and sensitivity of PSA by employing 25 nm colloidal AuNPs conjugated with anti-PSA antibody LSPR and monitoring the LSPR changes occurring as a consequence of AuNPs’ aggregation induced by antibody-antigen reaction. The same LSPR-based approach was exploited by Salahvarzi and coworkers [ 47 ] to develop an immunoassay based on AuNPs for detecting thyroid stimulating hormone (TSH), used for monitoring thyroid associated diseases, in human blood serum.…”