Standard-free single magnetic bead evaluation: a stable nanoplatform for prostate disease differentiation

Abstract

Explicit interpretation of heterogeneity between prostate-specific antigen (PSA) subtypes is essential for prostate cancer differentiation during different disease courses, whereas a universal protocol with uniform criteria is still lacking across the globe. In this work, a standard-free single magnetic bead (SMB) nanoplatform utilizing metal nanoparticles with optimal diameters was proposed for prostate disease differentiation in a 134-donor model. The inaccuracy of detection in absolute quantification was diminished via evaluations of metal intensities on the single magnetic bead. The intrinsic proportion of fPSA in tPSA was successfully evaluated by direct use of the Pt to Au intensity ratio (Pt/Au ratio), exhibiting better differentiation between healthy and unhealthy, benign prostatic hyperplasia (BPH) and cancer individuals compared with solo fPSA or tPSA. We generated thresholds respectively for prostate disease differentiation, envisioning that this standard-free SMB nanoplatform would establish a standardized methodology with uniform criteria worldwide in cancer diagnosis, staging, and postoperative assessments.

Fig. 1. (A) and (B) schematic illustration of the proposed SMB nanoplatform for prostate disease differentiation. (C) Mass scanning of magnetic beads, AuNPs, and PtNPs. (D) Dual-biomarker evaluation using the SMB nanoplatform with the same number of magnetic beads. (E) Stable data processing of the SMB nanoplatform with varied numbers of magnetic beads.

Fig. 2. Characterization of the dual-biomarker immunoassay using (A) (blank) and (D) TEM, (B) (blank) and (E) SEM, as well as (C) (blank) and (F) EDS. The concentrations of fPSA and tPSA were 100 ng mL⁻¹.

Fig. 3. Efficiency of diameter-regulation immunoassays using PtNPs (A) and AuNPs (B) with three different diameters using the S/N ratio. Simulation of the immunoassay using AuNPs with a small (C), suitable (D), and large (E) diameter.

Fig. 4. (A) SMB nanoplatform for simultaneous detection of fPSA and tPSA. (B) Data comparison between samples measured by using the SMB nanoplatform and samples with known concentrations from the hospital. (C) Stability of the SMB nanoplatform over 8 days. (D) Consistency between % fPSA and the Pt/Au ratio in 20 patients.

Fig. 5. Distributions of solo tPSA (A), solo fPSA (D) and the Pt/Au ratio (G) among healthy donors, BPH and prostate cancer patients (Dotted line represents the mean value of the expression. *p < 0.05, **p < 0.01, ***p < 0.001). The distinction between BPH and cancer using solo tPSA or fPSA was tiny (p was 0.67 for solo tPSA and 0.59 for solo fPSA). (B) and (C) illustrate the ROC curves of solo tPSA for differentiation between healthy and BPH, and BPH and cancer. (E) and (F) illustrate the ROC curves of solo fPSA for differentiation between healthy and BPH, and BPH and cancer. (H) and (I) illustrate the ROC curves of the Pt/Au ratio for differentiation between healthy and BPH, and BPH and cancer.