fluorescent-lateral-flow-immunoassay-based-on-quantum-dots-nanobeads

Fluorescent Lateral Flow Immunoassay Based on Quantum Dots Nanobeads

Quantum dots, also known as semiconductor nanocrystals, are novel fluorescent labels for biological imaging and sensing. However, quantum dot-antibody ...

Tongji University

A highly sensitive quantum dot (QD)-based western blot assay with extended dynamic range was developed. Bimodal size distribution QD (BQ) immunoprobes composed of small size single QD (7.3 nm) and big size QD nanobead (QB) (82.9 nm) were employed for fluorescent western blot immunoassay on a membrane. Small size QD immunoprobes contributed to wider dynamic range of assay, while big size QB immunoprobes provided higher detection sensitivity. This BQ-based western blot assay can achieve a wide dynamic range (from 7.8 to 4000 ng IgG) and is nearly as sensitive as commercial available ultrasensitive chemiluminescent methods, just using a simple gel imager with UV light (365 nm) excitation and red light filter (610 nm). The fluorescent signals of BQ western blot were stable for 10 min, while chemiluminescent signals faded after 1 min. Moreover, this BQ immunoprobe was utilized for the detection of housekeeping protein and specific target proteins in complex cell lysate samples. The limit of detection of housekeeping protein is 0.25 μg of cell lysate, and the signal intensities were proportional to loading protein amount in a wide range from 0.61 to 80 μg. We believe that this new strategy of bimodal size distribution nanoparticles can also be expanded for other functional nanoparticle-based biological assays to improve the sensitivity and extend the dynamic range. Graphical abstract.

Bimodal size distribution immuno-quantum dots for fluorescent western blotting assay with high sensitivity and extended dynamic range.

The incidence of fungal infections has increased continuously in recent years. Caspofungin (CAS) is one of the first-line drugs for the treatment of systemic fungal infection. However, the emerging CAS-resistant clinical isolates and high economic cost for CAS administration hamper the wide application of this drug. Thus, the combined administration of CAS with other compounds that can enhance the antifungal activity and reduce the dose of CAS has gained more and more attention. In this study, we investigated the effect of mangiferin (MG) on the antifungal activities of CAS. Our results showed that MG acted synergistically with CAS against various ., including CAS-resistant . Moreover, MG could enhance the activity of CAS against biofilm. The  synergism of MG and CAS was further confirmed in a mouse model of disseminated candidiasis. To explore the mechanisms, we found that SPE1-mediated polyamine biosynthesis pathway was involved in the fungal cell stress to caspofungin. Treatment of CAS alone could stimulate SPE1 expression and accumulation of polyamines, while combined treatment of MG and CAS inhibited SPE1 expression and destroyed polyamine accumulation, which might contribute to increased oxidative damage and cell death. These results provided a promising strategy for high efficient antifungal therapies and revealed novel mechanisms for CAS resistance.

Mangiferin enhances the antifungal activities of caspofungin by destroying polyamine accumulation.

In most cases, dermatofibrosarcoma protuberans (DFSP) is characterized by the chromosomal translocation t (17; 22) (q22; q13) that leads to a fusion of collagen type 1 alpha 1 (COL1A1) and platelet-derived growth factor beta chain (PDGFB). Recently, next-generation sequencing (NGS) has been reported to detect fusion transcripts in some malignancies. Therefore, the present study aimed to evaluate the utility of the targeted NGS in detecting the COL1A1-PDGFB fusion in patients with DFSP.

Determination of COL1A1-PDGFB breakpoints by next-generation sequencing in the molecular diagnosis of dermatofibrosarcoma protuberans.

Fluorescent lateral flow immunoassay (LFA) systems are versatile tools for sensitive and quantitative detection of disease markers at the point of care. However, traditional fluorescent nanoparticle-based lateral flow immunoassays are not visible under room light, necessitate an additional fluorescent reader, and lack flexibility for different application scenarios. Herein, we report a dual-readout LFA system for the rapid and sensitive detection of C-reactive protein (CRP) in clinical samples. The system relied on the aggregation-induced emission nanobeads (AIENBs) encapsulated with red AIE luminogen, which possesses both highly fluorescent and colorimetric properties. The AIENB-based LFA in the naked-eye mode was able to qualitatively detect CRP levels as low as 8.0 mg/L, while in the fluorescent mode, it was able to quantitatively measure high-sensitivity CRP (hs-CRP) with a limit of detection of 0.16 mg/L. The AIENB-based LFA system also showed a good correlation with the clinically used immunoturbidimetric method for CRP and hs-CRP detection in human plasma. This dual-modal AIENB-based LFA system offers the convenience of colorimetric testing and highly sensitive and quantitative detection of disease biomarkers and medical diagnostics in various scenarios.

One-Component Dual-Readout Aggregation-Induced Emission Nanobeads for Qualitative and Quantitative Detection of C-Reactive Protein at the Point of Care.

Lingzhi Fan

Department of Central Laboratory,
Shanghai Skin Disease Hospital,
School of Medicine,
Department of Central Laboratory, Shanghai Skin Disease Hospital, School of Medicine

Tongji University

Fluorescent Lateral Flow Immunoassay Based on Quantum Dots Nanobeads

Lingzhi Fan

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Central Laboratory,Shanghai Skin Disease Hospital,School of Medicine,Department of Central Laboratory, Shanghai Skin Disease Hospital, School of Medicine

Tongji University

Fluorescent Lateral Flow Immunoassay Based on Quantum Dots Nanobeads

Department of Central Laboratory,
Shanghai Skin Disease Hospital,
School of Medicine,
Department of Central Laboratory, Shanghai Skin Disease Hospital, School of Medicine