Engineered Collaborative Size Regulation and Shape Engineering of Tremella‐Like Au‐MnO_x for Highly Sensitive Bimodal‐Type Lateral Flow Immunoassays

Abstract

Engineered collaborative size regulation and shape engineering of multi‐functional nanomaterials (NPs) offer extraordinary opportunities for improving the analysis performance. It is anticipated to address the difficulty in distinguishing color changes caused by subtle variations in target concentrations, thereby facilitating the highly sensitive analysis of lateral flow immunoassays (LFIAs). Herein, tremella‐like gold‐manganese oxide (Au‐MnOx) nanoparticles with precise MnCl2 regulation are synthesized as immuno signal tracers via a facile one‐step redox reaction in alkaline condition at ambient temperature. Avail of the tunable elemental composition and anisotropy in morphology, black‐colored tremella‐like Au‐MnOx exhibits superb colorimetric signal brightness, enhanced antibody coupling efficiency, marvelous photothermal performance, and unrestricted immunological recognition affinity, all of which facilitate highly sensitive multi‐signal transduction patterns. In conjunction with the handheld thermal reader device, a bimodal‐type LFIA that combines size‐regulation‐ and shape‐engineering‐mediated colorimetric‐photothermal dual‐response assay (coined as the SSCPD assay) with a limit of detection of 0.012 ng mL−1 for ractopamine (RAC) monitoring is achieved by integrating Au‐MnOx with the competitive‐type immunoreaction. This work illustrates the effectiveness of this strategy for establishing high‐performance sensing, and the SSCPD assay may be extended to a wide spectrum of future point‐of‐care (POC) diagnostic applications.

Precise Spectral Overlap-Based Donor–Acceptor Pair for a Sensitive Traffic Light-Typed Bimodal Multiplexed Lateral Flow Immunoassay

“…For the detection of RAC and CLE in pork by using the APNPs-LFIA, the treatment method was referred to in previous reports. ,, By the standard addition method, 1 g of chopped pork was dissolved in 2 mL of trichloroacetic acid (3%, v/v) and then shaken for 10 min. After centrifugation to remove the precipitation, the pH value was adjusted to ∼7.2 and filtered by a 0.22 μm sized filter membrane.…”

“…3 First, the AuNPs were synthesized by the classical reduction scheme. 15 Second, 30 mL of AuNPs was treated with K 3 [Fe(CN) 6 ] (0.5 mM) for 10 min, and then FeCl 3 •6H 2 O (0.1 mM) and K 4 [Fe(CN) 6 ] (0.1 mM) were added under vigorous stirring for 3 h. The APNPs were purified by centrifugation with water. PBNPs were synthesized by adding 6 g of PVP K30 and 0.264 g of K 3 [Fe(CN) 6 ]•3H 2 O to 80 mL of 0.01 M HCl solution, and then the mixture was heated at 80 °C for 20 h in an electric oven.…”

Trifunctional Nanocomposites with Colorimetric Magnetic Catalytic Activities Labels in Sandwich Immunochromatographic Detection of Escherichia coli O157:H7

“…Benefiting from the advantages of equipment-free (with visible results), user-friendly (accessible for home-based onsite test), and rapid-detection (analyzing within 5–30 min), lateral flow immunoassays (LFIAs) have received increasing attention in the field of on-site testing (POCT) of Escherichia coli O157:H7 . However, conventional AuNP-labeled LFIA suffers from several drawbacks such as the insufficient brightness of the colorimetric signal of AuNPs; the low antibody loading capacity; and the limited accuracy of detection results due to single optical signals . Fortunately, the emergence of nanoenzymes has led to a flourishing development of LFIA.…”

“…1 However, conventional AuNP-labeled LFIA suffers from several drawbacks such as the insufficient brightness of the colorimetric signal of AuNPs; 2 the low antibody loading capacity; 3 and the limited accuracy of detection results due to single optical signals. 4 Fortunately, the emergence of nanoenzymes has led to a flourishing development of LFIA. In nanoenzyme-based LFIA, nanoenzymes are not only used as signal generators and targets but also play a key role in sensor sensitivity and anti-interference performance through their catalytic and colorimetric abilities.…”

Dual-Readout Ultrasensitive Lateral Flow Immunosensing of Salmonella typhimurium in Dairy Products by Doping Engineering-Powered Nanoheterostructure with Enhanced Photothermal Performance

“…Therefore, outstanding photothermal conversion performance is one of the important strategies for upgrading detection sensitivity. , Enhancing photothermal conversion has aroused great substantial interest, , which principally depends on various nanomaterials, such as hollow nanoparticles, high-roughness noble metal nanomaterials, and even black nanoparticles from natural sources . Regulating the size, morphology, and structure of metal nanomaterials is essential to improve the plasmon on surface, which is to enhance the free electron resonance phenomenon near the surface of the nanomaterials and improve the absorption efficiency of incident light. , Recently, the construction of plasmon based on diverse kinds of nanomaterials to improve the efficiency of plasmon excitation . However, the simple resonant frequency cannot satisfy the sensitive photothermal response, and even other semiconductor materials are demanded …”