Facile synthesis of near-infrared-excited NaYF4:Yb3+, Tm3+ nanoparticles for label-free detection of dopamine in biological fluids

Recent Advances in Catecholamines Analytical Detection Methods and Their Pretreatment Technologies

Catecholamines (CAs), including adrenaline, noradrenaline, and dopamine, are neurotransmitters and hormones that play a critical role in regulating the cardiovascular system, metabolism, and stress response in the human body. As promising methods for real-time monitoring of catecholamine neurotransmitters, LC-MS detectors have gained widespread acceptance and shown significant progress over the past few years. Other detection methods such as fluorescence detection, colorimetric assays, surface-enhanced Raman spectroscopy, and surface plasmon resonance spectroscopy have also been developed to varying degrees. In addition, efficient pretreatment technology for CAs is flourishing due to the increasing development of many highly selective and recoverable materials. There are a few articles that provide an overview of electrochemical detection and efficient enrichment, but a comprehensive summary focusing on analytical detection technology is lacking. Thus, this review provides a comprehensive summary of recent analytical detection technology research on CAs published between 2017 and 2022. The advantages and limitations of relevant methods including efficient pretreatment technologies for biological matrices and analytical methods used in combination with pretreatment technology have been discussed. Overall, this review article provides a better understanding of the importance of accurate CAs measurement and offers perspectives on the development of novel methods for disease diagnosis and research in this field.

An improved up-conversion nanoparticles-based immunochromatographic assay for rapid detection of zearalenone in cereals

A novel improved up-conversion nanoparticles-based immunochromatographic assay (IUCNPs-ICA) was developed for the detection of zearalenone (ZEN). Lu³⁺-doped UCNPs were synthesized using the solvothermal method, and the UCNPs doped with 30 % Lu³⁺ displayed optimal optical properties. The IUCNPs-ICA was subsequently developed for the detection of ZEN in cereals under optimized conditions. The detection time and limit of detection (LOD) were 10 min and 0.1 μg/L, respectively. Moreover, a good linear relationship was observed from 0 to 100 μg/L ZEN (r² = 0.9946) and high specificity for other mycotoxins. LODs in spiked maize and wheat reached 0.16 μg/kg, and recovery rates were 82.11-100.76 % and 79.64-98.51 %. There was good consistency between the results of IUCNPs-ICA, colloidal gold-ICA, and high-performance liquid chromatography (HPLC) in the detection of natural cereal samples. The collective results support the utility of IUCNPs-ICA as a reliable on-site screening method for ZEN residue analysis in various cereals.

The Coming of Age of Neodymium: Redefining Its Role in Rare Earth Doped Nanoparticles

Among luminescent nanostructures actively investigated in the last couple of decades, rare earth (RE³⁺) doped nanoparticles (RENPs) are some of the most reported family of materials. The development of RENPs in the biomedical framework is quickly making its transition to the ∼800 nm excitation pathway, beneficial for both in vitro and in vivo applications to eliminate heating and facilitate higher penetration in tissues. Therefore, reports and investigations on RENPs containing the neodymium ion (Nd³⁺) greatly increased in number as the focus on ∼800 nm radiation absorbing Nd³⁺ ion gained traction. In this review, we cover the basics behind the RE³⁺ luminescence, the most successful Nd³⁺-RENP architectures, and highlight application areas. Nd³⁺-RENPs, particularly Nd³⁺-sensitized RENPs, have been scrutinized by considering the division between their upconversion and downshifting emissions. Aside from their distinctive optical properties, significant attention is paid to the diverse applications of Nd³⁺-RENPs, notwithstanding the pitfalls that are still to be addressed. Overall, we aim to provide a comprehensive overview on Nd³⁺-RENPs, discussing their developmental and applicative successes as well as challenges. We also assess future research pathways and foreseeable obstacles ahead, in a field, which we believe will continue witnessing an effervescent progress in the years to come.

Application of rare earth-doped nanoparticles in biological imaging and tumor treatment

Rare earth-doped nanoparticles have been widely used in disease diagnosis, drug delivery, tumor therapy, and bioimaging. Among various bioimaging methods, the fluorescence imaging technology based on the rare earth-doped nanoparticles can visually display the cell activity and lesion evolution in living animals, which is a powerful tool in biological technology and has being widely applied in medical and biological fields. Especially in the band of near infrared (700–1700 nm), the emissions show the characteristics of deep penetration due to low absorption, low photon scattering, and low autofluorescence interference. Furthermore, the rare earth-doped nanoparticles can be endowed with the water solubility, biocompatibility, drug-loading ability, and the targeting ability for different tumors by surface functionalization. This confirms its potential in the cancer diagnosis and treatment. In this review, we summarized the recent progress in the application of rare earth-doped nanoparticles in the field of bioimaging and tumor treatment. The luminescent mechanism, properties, and structure design were also discussed.

Upconversion luminescence nanoparticles-based immunochromatographic assay for quantitative detection of triamcinolone acetonide in cosmetics

Triamcinolone acetonide (TCA) abuse in cosmetics is a common phenomenon. A rapid lateral flow immunochromatographic assay (ICA) was developed for the quantitative detection of TCA using a probe based on upconversion luminescence nanoparticles. Lanthanide-doped upconversion nanoparticles (UCNPs) were synthesized in a system comprising water and ethylene glycol, and a silicon dioxide layer was covered at the carboxyl site. A binding site protection strategy was used to decrease the background signal of UCNPs-ICA. Using dexamethasone derivative as a coating antigen, the optimal UCNPs-ICA exhibits good dynamic linear detection for TCA in the range 1.0-100 ng mL^-1 with a median inhibitory concentration of 9.8 ng mL^-1. The detection limits for TCA in a cosmetic sample are 20 μg kg^-1. The pretreatment of samples only needs dilution with water, suggesting the assay can quantitate TCA on-site using a portable upconversion luminescence reader with a cumulative analysis time of only 10 min.

A critical comparison of lanthanide based upconversion nanoparticles to fluorescent proteins, semiconductor quantum dots, and carbon dots for use in optical sensing and imaging

The right choice of a fluorescent probe is essential for successful luminescence imaging and sensing and especially concerning in vivo and in vitro applications, the development of new classes have gained more and more attention in the last years. One of the most promising class are upconversion nanoparticles (UCNPs)-inorganic nanocrystals capable to convert near-infrared light in high energy radiation. In this review we will compare UCNPs with other fluorescent probes in terms of (a) the optical properties of the probes, such as their brightness, photostability and excitation wavelength; (b) their chemical properties such as the dispersibility, stability under experimental or physiological conditions, availability of chemical modification strategies for labelling; and (c) the potential toxicity and biocompatibility of the probe. Thereby we want to provide a better understanding of the advantages and drawbacks of UCNPs and address future challenges in the design of the nanocrystals.

Mutual energy transfer luminescent properties in novel CsGd(MoO4)2:Yb3+,Er3+/Ho3+ phosphors for solid-state lighting and solar cells

In this work, we prepared a novel kind of Yb3+,Er3+/Ho3+ co-doped CsGd(MoO4)2 phosphors with a different structure from the reported ALn(MoO4)2 (A = Li, Na or K; Ln = La, Gd or Y) compounds using a high-temperature solid-state reaction method. X-ray diffraction showed that the as-prepared samples had a pure phase. Based on the efficient energy transfer from Yb3+ to Er3+/Ho3+, the up-conversion (UC) luminescence of the optimal CsGd(MoO4)2:0.30Yb3+,0.02Er3+ sample showed intensely green light with dominant emission peaks at 528 and 550 nm corresponding to Er3+ transitions 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2, respectively, as well as a weak emission peak originating from 4F9/2 → 4I15/2 at 671 nm, under 975 nm laser excitation. The CsGd(MoO4)2:Yb3+,Ho3+ samples mainly displayed two emission bands around 540 and 660 nm together with a negligible one at 755 nm, which corresponded to Ho3+ transitions 4F4,5F2 → 5I8, 5F5 → 5I8 and 4F4,5F2 → 5I7, respectively, under 975 nm laser excitation. With increasing Yb3+ concentration in CsGd(MoO4)2:Yb3+,Ho3+ phosphors, the emission color could be tuned from orange red to light yellow due to the large energy gap between levels 4F4,5F2 and 5F5. In addition, the CsGd(MoO4)2:Yb3+,Er3+ showed green light under 376 nm UV irradiation similar to that upon 975 nm laser excitation. However, the emissions for CsGd(MoO4)2:Yb3+,Ho3+ samples under 358 nm UV or 449 nm blue excitation showed dominant emission peaks at 540 nm and weak 660 nm and 752 nm peaks, which were a bit different from those under 975 nm excitation. Interestingly, we observed efficient energy transfer phenomena (possible quantum cutting) from Er3+/Ho3+ to Yb3+ and a Yb3+-O2- charge transfer (CT) transition in the molybdates, which was deduced from the visible and near-infrared emission spectra and the decrease of the Er3+/Ho3+ luminescent lifetimes with increasing Yb3+ concentration in the CsGd(MoO4)2:Yb3+,Er3+/Ho3+ samples. The luminescence properties of these phosphors suggest their potential possibility for applications in solid-state lighting and displays as well as in c-Si solar energy conversion systems.

Photoinduced holes transfer based visual determination of dopamine in human serum

A simple unexplored strategy was followed to construct ratiometric fluorescence-based sensing system for the detection of dopamine (DA) in human serum. Ratiometric fluorescence system was constructed through bonding energy transfer (TBET) by conjugating carboxyl functionalized CdTe quantum dots (QDs) and amine-capped Carbon quantum dots (CQDs). The photophysical properties of sensing system were characterized by standard methods. Photoluminescence (PL) of sensing system under excitonic wavelength (350 nm) depends on dual emission at 440 and 595 nm that corresponds to CQDs and CdTe QDs respectively. The developed sensing system was utilized for visual determination of DA, an unquenched blue fluorescence of CQDs in ratiometric system reveals the visual color differentiation for DA binding with CdTe QDs among the possible interferences (Alanine, Glycine, Glucose, Sucrose, Urea and Ascorbic acid). The limit of detection (LOD) and quantification (LOQ) was calculated as 8.1 and 27.2 nm respectively by using regression analysis. Photoinduced holes transfer (PHT) might have attributed the possible sensing mechanism for DA that quench the photoluminescence sequentially to enhance the sensing performance of QDs. The matrix interferences and reliability of the developed sensing platform were evaluated by testing DA spiked human serum and the sensing response was found to be field deployable.

A “turn-on” sensor based on MnO2coated UCNPs for detection of alkaline phosphatase and ascorbic acid

A “turn-on” sensor was designed to detect ALP and AA based on the redox reaction between AA and MnO₂coated UCNPs.