In this study, a novel colorimetric aptasensor was developed for the rapid and visual detection of human papillomavirus type 16 (HPV16) L1 proteins using gold nanoparticles (AuNPs) and an RNA aptamer specifically targeting HPV16 L1 protein (APTHPV16 L1). The method relies on salt-induced aggregation of AuNP-APTHPV16 L1 conjugates in the presence of HPV16 L1 proteins at trace levels (ppb). Upon addition of salt, the conjugates aggregate due to specific binding between APTHPV16 L1 and HPV16 L1, resulting in a distinct color change from red to blue. This shift is attributed to a significant alteration in surface plasmon resonance (SPR) absorption peaks of AuNPs, which move toward shorter wavelengths. The relative absorbance ratio (Ablank – Asample)/Ablank at 520 nm demonstrated a stable and linear response across a concentration range of 9.6 to 201.6 ng mL⁻¹, indicating high sensitivity and reproducibility. The visual detection limit was determined to be as low as 9.6 ng mL⁻¹, enabling naked-eye identification of target proteins without complex instrumentation.
The proposed aptasensor exhibited excellent selectivity against structurally similar proteins, including HPV6 L1 and HPV18 L1, confirming minimal cross-reactivity. This specificity arises from the high-affinity interaction between APTHPV16 L1 and HPV16 L1 (KD = 0.05 pM), which triggers conformational changes leading to aptamer detachment and subsequent nanoparticle aggregation. The assay was validated through extensive characterization using UV-Vis spectroscopy, zeta potential measurements, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). These analyses confirmed that AuNPs remained dispersed when bound to APTHPV16 L1 but aggregated upon exposure to HPV16 L1 proteins under high-salt conditions.
The practical applicability of the sensor was further demonstrated by its successful use in detecting HPV16 L1 proteins in both clinical samples and vaccine formulations. Results obtained from real sample testing were consistent with those from enzyme-linked immunosorbent assay (ELISA), a gold-standard method, thereby verifying the accuracy and reliability of the colorimetric approach. Recovery rates ranged from 74.8% to 85.4%, with acceptable relative standard deviations (RSDs) between 1.STAT5B Antibody Purity 5% and 2.838818-26-1 Biological Activity 8%, confirming robust performance in complex matrices.PMID:34278583 Additionally, the AuNP-APTHPV16 L1 conjugates showed excellent stability over 48 hours, ensuring reagent shelf-life and operational convenience.
This work presents a simple, cost-effective, sensitive, and selective platform for the rapid screening and quantitative analysis of HPV16 L1 proteins. Its visual readout capability makes it highly suitable for point-of-care diagnostics, especially in resource-limited settings. By combining the advantages of aptamer specificity and AuNP-based optical signaling, the proposed aptasensor offers a promising alternative to conventional immunoassays and mass spectrometry-based methods. It holds strong potential for improving early detection of cervical cancer risk, monitoring vaccine efficacy, and enhancing personalized clinical management of HPV-related diseases.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com