Novel fluorescent nano-sensor based on amino-functionalization of Eu3+:SrSnO3 for copper ion detection in food and real drink water samples

A bacterial cellulose-based LiSrVO4:Eu3+ nanosensor platform for smartphone sensing of levodopa and dopamine: point-of-care diagnosis of Parkinson's disease

Among the catecholamines, dopamine (DA) is essential in regulating multiple aspects of the central nervous system. The level of dopamine in the brain correlates with neurological diseases such as Parkinson's disease (PD). However, dopamine is unable to cross the blood-brain barrier (BBB). Therefore, levodopa (LD) is used to restore normal dopamine levels in the brain by crossing the BBB. Thus, the control of LD and DA levels is critical for PD diagnosis. For this purpose, LiSr0.0985VO4:0.015Eu3+ (LSV:0.015Eu3+) nanoplates were synthesized by the microwave-assisted co-precipitation method, and have been employed as an optical sensor for the sensitive and selective detection of catecholamines. The synthesized LSV:0.015Eu3+ nanoplates emitted red fluorescence with a high quantum yield (QY) of 48%. By increasing the LD and DA concentrations, the fluorescence intensity of LSV:0.015Eu3+ nanoplates gradually decreased. Under optimal conditions, the linear dynamic ranges were 1-40 μM (R2 = 0.9972) and 2-50 μM (R2 = 0.9976), and the detection limits (LOD) were 279 nM, and 390 nM for LD and DA, respectively. Herein, an instrument-free, rapid quantification visual assay was developed using a paper-based analytical device (PAD) with LSV:0.015Eu3+ fixed on the bacterial cellulose nanopaper (LEBN) to determine LD and DA concentrations with ease of operation and low cost. A smartphone was coupled with the PAD device to quantitatively analyze the fluorescence intensity changes of LSV:0.015Eu3+ using the color recognizer application (APP). In addition, the LSV:0.015Eu3+ nanosensor showed acceptable repeatability and was used to analyze real human urine, blood serum, and tap water samples with a recovery of 96-107%.

Recent progress on quality improvement and detection technologies of special foods used for activities in space and aviation: a review

This paper focuses on the development and evolution, quality improvement and research progress in the rapidly emerging area of new detection technologies of special foods for use in space and to some extent aviation. The quality improvement aspects covered in this review ranged from the special food processing technology, sterilization treatment and product packaging to new detection technologies for quality assurance based on DNA microarray technology, sensor, imaging technology, carbon nanotubes and novel probe technology.

Ultrasound-assisted synthesis of europium doped BPO4 nanoparticles; a new approach for Zn2+ (aq) detection

In this work, europium ion was doped into boron phosphate nanoparticles (BPO₄) using an ultrasonic method followed by the calcination process. The nanoparticles were characterized by various techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy, transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, and scanning electron microscopy (SEM). Doping of europium ion into the BPO₄ host crystal was proved by cell volume calculation from XRD patterns, the shift in Raman spectra, and photoluminescence properties. In addition, the europium doped boron phosphate (BPE) as a fluorescence sensor for the quantification of Zn²⁺ cation was studied. The obtained results showed the enhancement and shift of the photoluminescence peak from 292 to 340 nm. The sensor's selectivity toward this ion was verified in the presence of a variety of common interfering cations. Surprisingly, BPE revealed excellent selectivity and sensitivity towards Zn²⁺ in the presence of Pb²⁺, Na⁺, Fe²⁺, Al³⁺, Ca²⁺, Mg²⁺, Cu²⁺, Co²⁺, Ni²⁺, Mn²⁺, Cd²⁺, Hg²⁺, Ba²⁺ and Fe³⁺ cations. The fluorescence response was linearly proportional to the Zn²⁺concentration. After the addition of trace amounts of Zn²⁺ ions into the aqueous solution, a significant enhancement of fluorescence emission occurred with the detection limit of 0.3 μM.