Dual lateral flow assay based on PdRu nanocages for human Papillomavirus detection.

Cervical cancer is one of the most common gynecological malignancies, with the vast majority of which being caused by persistent infection with Human Papillomavirus (HPV) 16 and 18. The current available HPV detection methods are sensitive and genotyped but are restricted by expensive instruments and skilled personnel. The development of an easy-to-use, rapid, and cost-friendly analysis method for HPV is of great need. Herein, hollow palladium-ruthenium nanocages modified with two oligonucleotides (PdRu capture probes) were constructed for genotyping and simultaneous detection of target nucleic acids HPV16 and HPV18 by dual lateral flow assay (DLFA). PdRu capture probes were endowed with bi-functions for the first time, which could be used to output signals and hybridize target nucleic acids. Under optimized conditions, the PdRu based-DLFA with detection limits of 0.93 nM and 0.19 nM, respectively, exhibited convenient operation, and high sensitivity. Meanwhile, the DLFA achieved excellent rapid detection within 20 min, which was attributed to capture probes that can be directly bound to amplification-free target nucleic acids. Therefore, the development of PdRu-based DLFA can be utilized for rapid, sensitive, and simultaneous genotyping detection of HPV16 and HPV18, showing great application for nucleic acid detection.

Rapid immunoassay for dual-mode detection of HPV16 and HPV18 DNA based on Au@PdPt nanoparticles.

Cervical cancer (CC) remains one of the most severe global health challenges affecting women, primarily due to persistent infection with high-risk human papillomavirus (HPV) subtypes, particularly with HPV16 and HPV 18. Effective detection of these high-risk HPV strains is crucial for CC prevention. Current screening programs for HPV DNA include PCR and in situ hybridization, which are accurate and sensitive. However, these approaches demand a high level of expertise, along with expensive instruments and consumables, thus hindering their widespread use. Therefore, there is a compelling demand to develop an efficient, straightforward, and cost-effective method. Herein, we propose a lateral flow immunoassay (LFIA) method based on Au@PdPt nanoparticles for the simultaneous detection and genotyping of HPV16 and HPV18 within 15 min. This innovative approach allows for qualitative assessment by the naked eye and enables semi-quantitative detection through a smartphone. In this study, under optimal conditions, the qualitative visual limits of detection (vLOD) for HPV16 and HPV18 reached 0.007 nM and 0.01 nM, respectively, which were 32-fold and 20-fold more sensitive than conventional AuNPs-LFIA for HPV16 and HPV18, respectively. Meanwhile, semi-quantitative limits of detection (qLOD) for HPV16 and HPV18 were 0.05 nM and 0.02 nM, respectively. In conclusion, our formulated approach represents a significant step forward in HPV detection and genotyping, with the potential to enhance accessibility and effectiveness in the early diagnosis of CC at the point of care and beyond.

An AgPd NP-based lateral flow immunoassay for simultaneous detection of glycocholic acid and alpha-fetoprotein.

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality globally, ranking third in cancer deaths. Early diagnosis of HCC markers is imperative for effective prognosis and treatment. This study explores the utility of glycocholic acid (GCA) and alpha-fetoprotein (AFP) as biomarkers for liver diseases, with a specific focus on their simultaneous detection for enhanced diagnostic and prognostic capabilities. Harnessing the benefits of lateral flow immunoassay (LFIA), such as operational simplicity, speed, and accuracy, we engineered AgPd nanocomposites with antibodies targeting GCA and AFP. Under the optimized conditions, the visual detection limit for GCA was established at 50 ng mL-1 and the cut-off value at 104 ng mL-1. And for AFP, the visual detection limit was 0.1 ng mL-1 and the cut-off value was 500 ng mL-1. The accuracy and feasibility of the strips were validated through the detection of 39 actual serum samples. The results highlight the potential of LFIA as a rapid and effective tool for clinical diagnosis. The developed LFIA method not only demonstrates accuracy and feasibility but also presents a promising avenue for the early diagnosis of hepatocellular carcinoma.

Multifunctional Au@Pt@Ag NPs with color-photothermal-Raman properties for multimodal lateral flow immunoassay.

Multimodal lateral flow immunoassay (LFIA) has displayed its potential to improve practicability and elasticity of point-of-care testing. Herein, multifunctional core-shell-shell Au@Pt@Ag NPs loaded with dual-layer Raman reporter molecules of 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) with a characteristic combination of color-photothermal-Raman performance were constructed for colorimetric LFIA (CM-LFIA), photothermal LFIA (PT-LFIA) and surface-enhanced Raman scattering-based LFIA (SERS-LFIA), respectively. The highly specific nanoprobes, being obtained through the combination of the resulted dual-layer DTNB modified Au@Pt@Ag NPs with the antibody, were triumphantly utilized in exploring multimodal LFIA with one visual qualitative and two optional quantitative modes with excellent sensing sensitivity. Under optimal conditions, the limit of detection (LOD) for the model hazardous analyte dehydroepiandrosterone (DHEA) were 1.0 ng mL-1 for CM-LFIA, 0.42 ng mL-1 for PT-LFIA, and 0.013 ng mL-1 for SERS-LFIA, three of which were over 100-fold, 200-fold and 7 000-fold more sensitive than conventional visual AuNPs-based LFIA, respectively. In addition, the quantitative PT-LFIA and SERS-LFIA sensors worked well in spiked real samples with acceptable recoveries of 96.2 - 106.7% and 98.2 - 105.2%, respectively. This assay demonstrated that the developed multimodal LFIA had a great potential to be a powerful tool for accurate tracing hazardous analytes in complex samples.

A Pt-Ir nanocube amplified lateral flow immunoassay for dehydroepiandrosterone.

The traditional gold-nanoparticle-based lateral flow immunoassay (LFIA) cannot satisfy the requirements for the sensitive detection of dehydroepiandrosterone (DHEA) in human urine. To enhance the sensitivity of the LFIA, platinum-iridium nanocubes (Pt-Ir NCs) with high catalytic efficiency and stability were synthesized and labelled with polyclonal antibody (pAb) to form a pAb-Pt-Ir probe. For the detection of DHEA, a novel LFIA with Pt-Ir NCs as an optical label and an enhanced LFIA in which the peroxidase-like activity of the Pt-Ir NCs was triggered by the introduction of the chromogenic substrate 3-amino-9-ethyl-carbazole (AEC) were developed and compared with a LFIA with platinum nanocubes (PtNCs) as an optical label. The visual limit of detection was 0.5 ng mL-1 for Pt-Ir-LFIA and 0.05 ng mL-1 for AEC-enhanced Pt-Ir-LFIA, in comparison to 100 ng mL-1 for PtNCs-LFIA and 50 ng mL-1 for AEC-enhanced PtNCs-LFIA. The average recoveries from spiked urine samples ranged from 90.8% to 110.4%, with a coefficient of variation below 12.6%, suggesting the accuracy and reliability of our developed immunoassay. Achieving excellent sensitivity, specificity, and reproducibility, Pt-Ir-LFIA provided a promising platform for monitoring DHEA.

Platinum nanoflowers with peroxidase-like property in a dual immunoassay for dehydroepiandrosterone.

Platinum nanoflowers (PtNFs) were utilized in a competitive enzyme-linked immunosorbent assay (ELISA) and in a lateral flow immunoassay (LFIA) for superior peroxidase-like activity and intense brown color, respectively. PtNFs were linked to the polyclonal antibody (pAb) to form the pAb-PtNFs probes for the dual immunoassay. Based on optimized pAb-PtNF probes, both enzyme-linked immunosorbent assay (PtNFs-ELISA) and lateral flow immunoassay (PtNFs-LFIA) perform very well. The absorbance at 450 nm decreases linearly in the DHEA concentration range 2.1 to 118.1 ng mL-1, and the limit of detection is 1.3 ng mL-1 and the IC50 value is 15.7 ng mL-1 of PtNFs-ELISA. The visual cut-off value of PtNFs-LFIA is 10.0 ng mL-1. The average recoveries from spiked samples range from 95.0 to 108.9% with a coefficient of variation below 12.2%. Excellent recoveries and correlation between the two methods were observed. Furthermore, the designed immunosensors exhibited good selectivity, confirming a broad development prospect in DHEA monitoring. Graphical Abstract.

Prussian blue nanoparticles with peroxidase-mimicking properties in a dual immunoassays for glycocholic acid.

Prussian Blue nanoparticles (PBNPs) were utilized in a lateral flow immunoassay (LFA) and in an indirect competitive nanozyme-linked immunosorbent assay (icELISA), respectively, for their intense blue color and peroxidase (POx) -like activity. The PBNPs with good POx-like activity was linked to the antibody. Under the optimal parameters, both the PBNP-icELISA and PBNP-LFA perform very well. The icELISA has an IC50 value of 190 ng/mL, the working range extends from 29 to 1200 ng/mL, and the limit of detection is 22 ng/mL. The visual cut-off limit is 10 ng/mL. The dual immunoassay was used to quantify glycocholic acid in spiked human urine. Excellent recoveries and correlation between the two methods were observed.