High-Density Gold Nanoparticles Implanted on Mg/Fe LDH Nanoflowers Assisted Lateral Flow Immuno-Dipstick Assay for Visual Detection of Human Epididymal Protein 4.

The timelier and more accurate the diagnosis of the disease, the higher the patient's survival rate. Human epididymal protein 4 (HE4) has great significance as a biomarker of concern for reflecting ovarian cancer. Herein, we prepared a novel optical label that can be used in lateral-flow immuno-dipstick assay (LFIA) for sensitive visual detection of HE4 by implanting hydrophobic gold nanoparticles (Au NPs) at high density in Mg/Fe LDH nanoflowers (MF NFs). MF NFs with large specific surface area, high porosity, abundant active binding sites, and stable structure were employed for the first time as templates to directly anchor Au NPs in the organic phase. After simple modification with an optimized amount of branched polyethyleneimine, not only could MF@Au NFs be dispersed in the aqueous phase, but also amino functional groups were introduced on its surface to facilitate subsequent antibody coupling steps. The limit of detection reaches 50 pM with a detection range of 50 to 1000 pM. This work initially explored how MF NFs can be used to load signal labels with ideal stability and signal amplification capabilities, which greatly improves the practicability of LFIA and highlights its important role in the field of rapid diagnostics.

Photonic crystal barcodes assembled from dendritic silica nanoparticles for the multiplex immunoassays of ovarian cancer biomarkers.

The combined detection of CA125, CEA and AFP is of great significance in the diagnosis of ovarian cancer. Photonic crystal (PhC) barcodes have apparent advantages in multiplex immunoassays of ovarian cancer markers. In this paper, a novel PhC barcode was assembled from dendritic silica nanoparticles (dSiO2) for multiplex detection of ovarian cancer biomarkers. The interconnected macroporous structure of the dSiO2 PhC beads and the open porous topography of dendritic silica particles could increase the surface area to volume ratio for antibody immobilization. We simultaneously detected multiple ovarian cancer markers in one test tube using the sandwich immunization method by utilizing dSiO2 PhC beads as a barcode and CdTe QDs as a detection signal. The detection limits of the three ovarian cancer markers, AFP, CEA and CA125, were 0.52 ng mL-1, 0.64 ng mL-1 and 0.79 U mL-1, respectively (the signal-to-noise ratio was 3). Compared with the classic silica colloidal crystal bead (SCCB) suspension array, the sensitivity of the dSiO2 PhC bead suspension array was increased. In addition, the results showed that this barcode suspension array had acceptable accuracy and good reproducibility.

Anodic near-infrared electrochemiluminescence from Cu-doped CdTe quantum dots for tetracycline detection.

A sensitive anodic near-infrared electrochemiluminescence (ECL) immunosensor for the detection of tetracycline, based on Cu-doped CdTe quantum dots, was fabricated for the first time in this work. We have synthesized Cu-doped CdTe quantum dots by co-precipitation. The emission spectrum of the Cu-doped CdTe quantum dots could reach the near-infrared region at 730 nm in a short reflux time. More importantly, the ECL intensity of the CdTe quantum dots was enhanced by 2 fold after Cu element doping, which was attributed to the Cu d-orbital mixed with the conduction band and valence band of the host CdTe quantum dots. Inspired by the strong anodic ECL intensity of Cu-doped CdTe quantum dots, the anodic near infrared ECL sensor was constructed to detect tetracycline by competitive immunoassay. The detection range of the developed biosensor was 0.01-10 ng mL-1 and the detection limit was 0.0030 ng mL-1. In addition, the biosensor showed outstanding selectivity, long-term stability and high reproducibility, which has great potential in the field of analysis and detection.

Anodic electrochemiluminescence from CsPbBr3 perovskite quantum dots for an alkaline phosphatase assay.

The ability to use ascorbic acid as a co-reactant to induce anodic electrochemiluminescence of CsPbBr3 perovskite quantum dots was investigated and observed in aqueous medium for the first time. Benefiting from its glorious anodic electrochemiluminescence emission, an ascorbic-acid-responsive electrochemiluminescence system was developed to detect alkaline phosphatase.