Synthesis of PDA-Mediated Magnetic Bimetallic Nanozyme and Its Application in Immunochromatographic Assay

Abstract

Immunochromatographic assay (ICA) is widely applied in various fields. However, severe matrix interference and weak signal output present major challenges in achieving accurate and ultrasensitive detection in ICA. Here, a polydopamine (PDA)-mediated magnetic bimetallic nanozyme (Fe 3 O 4 @PDA@Pd/Pt) with peroxidase-like activity was synthesized and used as a probe in ICA. The magnetic property of Fe 3 O 4 @PDA@Pd/Pt enabled effective magnetic enrichment of targets, thereby reducing the matrix interference in the sample. PDA coating on the magnetic bimetallic nanozyme was employed as a mediator and a stabilizer. It improved the catalytic ability and stability of the magnetic bimetallic nanozyme by providing more coordination sites for Pd/Pt growth and functional groups (−NH and −OH). In addition, the Pd/Pt bimetallic synergistic effect could further enhance the catalytic ability of the nanozyme. A method was developed by integrating Fe 3 O 4 , PDA, and Pd/Pt into Fe 3 O 4 @PDA@Pd/Pt as a probe in ICA. With the proposed method, human chorionic gonadotropin and Escherichia coli O157:H7 were successfully detected to be as low as 0.0094 mIU/mL in human blood serum and 9 × 10 1 CFU/mL in the milk sample, respectively. This method may be readily adapted for accurate and ultrasensitive detection of other biomolecules in various fields.

Immunochromatographic Assay Based on Polydopamine-Decorated Iridium Oxide Nanoparticles for the Rapid Detection of Salbutamol in Food Samples

“…The ζ-potential indicated the stability of the nanodispersion. The absolute values of the ζ-potential in 0–10 mV, 10–20 mV, 20–30 mV, and above 30 mV were defined as extreme instability, relative stability, moderate stability, and high stability, respectively . Thus, the IrO 2 @PDA-10 was the most stable, which was selected as the signal label of ICA for the follow-up experiments.…”

“…Figure 1B showed that IrO 2 NPs, IrO 2 @PDA-5, IrO 2 @PDA-10, IrO 2 @PDA-15, and IrO 2 @PDA-20 had ζ-potentials of −5. 33 Thus, the IrO 2 @PDA-10 was the most stable, which was selected as the signal label of ICA for the follow-up experiments.…”

Nanozyme enhanced magnetic immunoassay for dual-mode detection of gastrin-17

“…The enhancement of immunochromatographic signals with nanozymes has become a new research hotspot in recent years. [17][18][19][20][21][22] Various nanozyme materials exhibit excellent catalytic activities by imitating the structure or function of natural enzymes, including metal and metal oxide nanoparticles (NPs), carbon nanomaterials, and various metal-organic frameworks. 23 Compared with proteases, nanozymes are characterized by higher catalytic stability, simple modification, and lower manufacturing costs.…”

Cysteamine-Gold Coated Carboxylated Fluorescent Nanoparticle Mediated Point-of-Care Dual-Modality Detection of the H5N1 Pathogenic Virus

“…Recent research has started to focus on developing POCT kits that are based on dual-mode on-site detection, which requires multiple noble nanoparticles or QDs. The metals such as Au-Ag, Au-Pt, Pt-Pd, and QDs have been used in RDT kits; however, so far improvements to the LOD have only been obtained using these methods with single-mode approaches [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Although our group has previously developed RDT devices for single-mode detection [ 22 ], several commercial EuNPs, such as florescent dyes [ 23 ], aliphatic amine latex beads [ 24 ], CdSe/CdS/ZnS QDs, and latex coated CdSe/CdS/ZnS QDs [ 17 ], show good sensitivity (93%) and specificity (100%).…”