Nanoparticle-based colorimetric sensors to detect neurodegenerative disease biomarkers

UiO-66-NH2 Metal-Organic Framework for the Detection of Alzheimer's Biomarker Aβ (1-42)

Neurodegenerative disorders pose a significant challenge to global healthcare, with Alzheimer's disease (AD) being one of the most prevalent forms. Early and accurate detection of amyloid-β (Aβ) (1-42) monomers, a key biomarker of AD pathology, is crucial for effective diagnosis and intervention of the disease. Current gold standard detection techniques for Aβ include enzyme-linked immunosorbent assay and surface plasmon resonance. Although reliable, they are limited by their cost and time-consuming nature, thus restricting their point-of-care applicability. Here we present a sensitive and rapid colorimetric sensor for the detection of Aβ (1-42) monomers within 5 min. This was achieved by harnessing the peroxidase-like activity of metal-loaded metal-organic frameworks (MOFs), specifically UiO-66-NH2, coupled with the strong affinity of Aβ (1-42) to the MOFs. Various metal-loaded MOFs were synthesized and investigated, and platinum-loaded UiO-66-NH2 was identified as the optimal candidate for our purpose. The Pt-loaded UiO-66-NH2 sensor demonstrated detection limits of 2.76 and 4.65 nM Aβ (1-42) monomers in water and cerebrospinal fluid, respectively, with a linear range from 0.75 to 25 nM (R2 = 0.9712), outperforming traditional detection techniques in terms of both detection time and complexity. Moreover, the assay was specific toward Aβ (1-42) monomers when evaluated against interfering compounds. The rapid and cost-effective sensor may help circumvent the limitations of conventional detection methods, thus providing a promising avenue for early AD diagnosis and facilitating improved clinical outcomes.

Recent advances in colorimetric sensors based on nanozymes with peroxidase-like activity

Nanozymes have been widely used to construct colorimetric sensors due to their advantages of cost-effectiveness, high stability, good biocompatibility, and ease of modification. The emergence of nanozymes greatly enhanced the detection sensitivity and stability of the colorimetric sensing platform. Recent significant research has focused on designing various sensors based on nanozymes with peroxidase-like activity for colorimetric analysis. However, with the deepening of research, nanozymes with peroxidase-like activity has also exposed some problems, such as weak affinity and low catalytic activity. In view of the above issues, existing investigations have shown that the catalytic properties of nanozymes can be improved by adding surface modification and changing the structure of nanomaterials. In this review, we summarize the recent trends and advances of colorimetric sensors based on several typical nanozymes with peroxidase-like activities, including noble metals, metal oxides, metal sulfides/metal selenides, and carbon and metal-organic frameworks (MOF). Finally, the current challenges and prospects of colorimetric sensors based on nanozymes with peroxidase-like activity are summarized and discussed to provide a reference for researchers in related fields.