Luminescence energy transfer detection of PSA in red region based on Mn2+-enhanced NaYF4:Yb, Er upconversion nanorods

Advances in fluorescence sensing enabled by lanthanide-doped upconversion nanophosphors

Lanthanide-doped upconversion nanoparticles (UCNPs), characterized by converting low-energy excitation to high-energy emission, have attracted considerable interest due to their inherent advantages of large anti-Stokes shifts, sharp and narrow multicolor emissions, negligible autofluorescence background interference, and excellent chemical- and photo-stability. These features make them promising luminophores for sensing applications. In this review, we give a comprehensive overview of lanthanide-doped upconversion nanophosphors including the fundamental principle for the construction of UCNPs with efficient upconversion luminescence (UCL), followed by state-of-the-art strategies for the synthesis and surface modification of UCNPs, and finally describing current advances in the sensing application of upconversion-based probes for the quantitative analysis of various analytes including pH, ions, molecules, bacteria, reactive species, temperature, and pressure. In addition, emerging sensing applications like photodetection, velocimetry, electromagnetic field, and voltage sensing are highlighted.

Recent advances in nanomaterials for prostate cancer detection and diagnosis

Despite the significant progress in the discovery of biomarkers and the exploitation of technologies for prostate cancer (PCa) detection and diagnosis, the initial screening of these PCa-related biomarkers using current...

Advanced nanoengineered-customized point-of-care tools for prostate-specific antigen

Change in the level of human prostate-specific antigen (PSA) is a major element in the development and progression of prostate cancer (PCa). Most of the methodologies are currently restricted to their application in routine clinical screening due to the scarcity of adequate screening tools, false reading, long assay time, and cost. Innovative techniques and the integration of knowledge from a variety of domains, such as materials science and engineering, are needed to provide sustainable solutions. The convergence of precision point-of-care (POC) diagnostic techniques, which allow patients to respond in real time to changes in PSA levels, provides promising possibilities for quantitative and quantitative detection of PSA. This solution could be interesting and relevant for use in PCa diagnosis at the POC. The approaches enable low-cost real-time detection and are simple to integrate into user-friendly sensor devices. This review focuses on the investigations, prospects, and challenges associated with integrating engineering sciences with cancer biology to develop nanotechnology-based tools for PCa diagnosis. This article intends to encourage the development of new nanomaterials to construct high-performance POC devices for PCa detection. Finally, the review concludes with closing remarks and a perspective forecast.

The mesoscale regulation of β-NaYF4:Yb3+/Er3+ with desired size and morphology via introducing Li+/K+ into a hydrothermal environment

The mesoscale regulation of NaYF₄:Yb³⁺/Er³⁺ in a hydrothermal system was developed. The evolution of the product has several stages: nucleation, aggregation, orientation growth and ripening.

Mn2+-doped NaYF4:Yb,Er upconversion nanoparticles for detection of uric acid based on the Fenton reaction

A novel fluorescence method for the determination of hydrogen peroxide (H₂O₂) and uric acid (UA) was developed. The procedure was based on the hydroxyl radicals (·OH), which effectively quenched the fluorescence of the Mn²⁺-doped NaYF₄:Yb,Er upconversion nanoparticles (UCNPs). Based on the property of Mn²⁺-doped NaYF₄:Yb,Er upconversion nanoparticles, the Fenton reaction and enzymatic reaction of uric acid, this method could be used for highly sensitive detection of H₂O₂ and uric acid. Under optimal conditions, we observed that the fluorescence quenching signal showed good linearity with the H₂O₂ concentration in the range of 3.00×10^-8 M ~ 6.00×10^-5 M, and the detection limit of this assay was 1.30×10^-8 M. Meanwhile, the linear concentration range for UA was 4.00×10^-9 M ~ 1.00×10^-5 M, and the lower limit of detection was 1.90×10^-9 M. Furthermore, the developed method was successfully used for the determination of UA levels in human serum with satisfactory results.

Redox luminescence switch based on Mn2+ -doped NaYF4 :Yb,Er upconversion nanorods

An redox luminescence switch was developed for the sensing of glutathione (GSH), l-cysteine (Cys) or l-ascorbic acid (AA) based on redox reaction. The Mn²⁺ -doped NaYF₄ :Yb,Er upconversion nanorods (UCNRs) with an emission peak located in the red region were synthesized. The luminescence intensity of the UCNRs could be quenched due to the Mn²⁺ could be oxidized to MnO₂ by KMnO₄ . Subsequently, when the AA, GSH or Cys was added into the MnO₂ modified upconversion nanosystem, which could reduced MnO₂ to Mn²⁺ and the luminescence intensity was recovered. The concentration ranges of the nanosystem are 0.500-3.375 mM (R²  = 0.99) for AA, 0.6250-11.88 mM (R²  = 0.99) for GSH and 0.6250-9.375 mM (R²  = 0.99) for Cys, respectively.

Aptamer biosensor for Salmonella typhimurium detection based on luminescence energy transfer from Mn2+-doped NaYF4:Yb, Tm upconverting nanoparticles to gold nanorods

A highly sensitive luminescent bioassay for the detection of Salmonella typhimurium was fabricated using Mn²⁺-doped NaYF₄:Yb,Tm upconversion nanoparticles (UCNPs) as the donor and gold nanorods (Au NRs) as the acceptor and utilizing an energy transfer (LET) system. Mn²⁺-doped NaYF₄:Yb,Tm UCNPs with a strong emission peak at 807nm were obtained by changing the doped ion ratio. Carboxyl-terminated Mn²⁺-doped NaYF₄:Yb,Tm UCNPs were coupled with S. typhimurium aptamers, which were employed to capture and concentrate S. typhimurium. The electrostatic interactions shorten the distance between the negatively charged donor and the positively charged acceptor, which results in luminescence quenching. The added S. typhimurium leads to the restoration of luminescence due to the formation of UCNPs-aptamers-S. typhimurium, which repels the UCNPs-aptamers from the Au NRs. The LET system does not occur because of the nonexistence of the luminescence emission band of Mn²⁺-doped NaYF₄:Yb,Tm UCNPs, which had large spectral overlap with the absorption band of Au NRs. Under optimal conditions, the linear range of detecting S. typhimurium was 12 to 5×10⁵cfu/mL (R=0.99). The limit of detection for S. typhimurium was as low as 11cfu/mL in an aqueous buffer. The measurement of S. typhimurium in milk samples was satisfied in accordance with the plate-counting method, suggesting that the proposed method was of practical value in the application of food security.

Choline sensing based on in situ polymerization of aniline on the surface of upconverting nanoparticles

We found that the upconversion luminescence of UCNPs could be efficiently quenched by PANI, and a novel choline detection strategy has been developed based on in situ polymerization of aniline on the surface of UCNPs.

Ultrasensitive Luminescent In Vitro Detection for Tumor Markers Based on Inorganic Lanthanide Nano-Bioprobes

Ultrasensitive and accurate detection of tumor markers is of vital importance for the screening or diagnosis of cancers at their early stages and for monitoring cancer relapse after surgical resection. Inorganic lanthanide (Ln3+) nanoparticles (NPs), owing to their superior physicochemical characteristics, are regarded as a new generation of luminescent nano-bioprobes in the field of cancer diagnosis and therapy. In this progress report, a focus is set on our recent efforts on the development of inorganic Ln3+-NPs as efficient luminescent nano-bioprobes for the ultrasensitive in vitro biodetection of tumor markers, with an emphasis on the dissolution-enhanced luminescent bioassay (DELBA), an emerging technique recently developed toward practical medical applications.

Controlled synthesis, bioimaging and toxicity assessments in strong red emitting Mn2+ doped NaYF4:Yb3+/Ho3+ nanophosphors

Rare earth, Yb³⁺/Ho³⁺ doped NaYF₄ nanophosphors co-doped with Mn²⁺ showed enhanced red emission under NIR irradiation and were successfully used for cancer cell imaging.

Cubic Cu2O nanoframes with a unique edge-truncated structure and a good electrocatalytic activity for immunosensor application

In this work, an ultrasensitive sandwich-type electrochemical immunosensor was developed for the quantitative detection of prostate specific antigen (PSA). Gold nanoparticles decorated 3-aminopropyltriethoxysilane functionalized graphene sheets (Au@APTES-GS) with a large specific surface area, good biocompatibility and superior electron transfer ability were employed as the matrix. In addition, cubic Cu2O nanoframes with hollow edges were employed as the label for the first time. Scanning electron microscope (SEM) images were used to confirm the nanostructure of Au@APTES-GS and Cu2O. Using square wave voltammetry (SWV) to monitor the electrocatalytic process, the signal amplification mechanism of the matrix and the label were explored successfully. Here we find that the unique edge-truncated structure of Cu2O nanoframes can load with a larger amount of redox mediators, ferrocenecarboxylic acid (Fc-COOH), offering a higher electrochemical signal response. Apart from that, Cu2O nanoframes have a good electrocatalytic activity towards the Fc-COOH and hydrogen peroxide (H2O2), making a contribution to further enhance the sensitivity of the fabricated immunosensor. Under optimal conditions, the proposed immunosensor achieved an ultrasensitive and specific detection of PSA, and displayed acceptable reproducibility, selectivity and stability. This work may provide an effective method for the clinical monitoring of tumor markers and demonstrate the potential application promising of nanoframes in the fabrication of immunosensors.