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%.

Development of an antibacterial and antioxidative nanofibrous membrane using curcumin-loaded halloysite nanotubes for smart wound healing: In vitro and in vivo studies.

Endowing wound dressings with drug delivery capability is a suitable strategy to transfer medicinal compounds locally to damaged skin layers. These dressings are especially useful for accelerating the healing rate in the cases of long-term treatment, and adding more functionalities to the platform. In this study, a wound dressing composed of polyamide 6, hyaluronic acid, and curcumin-loaded halloysite nanotubes (PA6/HA/HNT@Cur) was designed and fabricated for wound healing applications. The physicochemical properties of this platform were investigated through Fourier-transform infrared spectroscopy and field-emission scanning electron microscopy. Moreover, wettability, tensile strength, swelling, and in vitro degradation were assessed. The HNT@Cur was incorporated in the fibers in three concentrations and 1 wt% was found as the optimum concentration yielding desirable structural and mechanical properties. The loading efficiency of Cur on HNT was calculated to be 43 ± 1.8%, and the release profiles and kinetics of nanocomposite were investigated at physiological and acidic pH. In vitro antibacterial and antioxidation studies showed that the PA6/HA/HNT@Cur mat had strong antibacterial and antioxidation activities against gram-positive and -negative pathogens and reactive oxygen species, respectively. Desirable cell compatibility of the mat was found through MTT assay against L292 cells up to 72 h. Finally, the efficacy of the designed wound dressing was evaluated in vivo; after 14 days, the results indicated that the wound size treated with the nanocomposite mat significantly decreased compared to the control sample. This study proposed a swift and straightforward method for developing materials that might be utilized as wound dressings in clinical settings.

Green Synthesis of Sulfur- and Nitrogen-Doped Carbon Quantum Dots for Determination of L-DOPA Using Fluorescence Spectroscopy and a Smartphone-Based Fluorimeter.

Sulfur- and nitrogen-doped carbon quantum dots (S,N-CQDs) were synthesized using feijoa leaves as a green precursor via a novel route. Spectroscopic and microscopic methods such as X-ray photoelectron spectroscopy, fluorescence spectroscopy, and high-resolution transmission electron microscopy were used to analyze the synthesized materials. The blue emissive S,N-CQDs were applied for qualitative and quantitative determination of levodopa (L-DOPA) in aqueous environmental and real samples. Human blood serum and urine were used as real samples with good recovery of 98.4-104.6 and 97.3-104.3%, respectively. A smartphone-based fluorimeter device was employed as a novel and user-friendly self-product device for pictorial determination of L-DOPA. Bacterial cellulose nanopaper (BC) was used as a substrate for S,N-CQDs to make an optical nanopaper-based sensor for L-DOPA determination. The S,N-CQDs demonstrated good selectivity and sensitivity. The interaction of L-DOPA with the functional groups of the S,N-CQDs via the photo-induced electron transfer (PET) mechanism quenched the fluorescence of S,N-CQDs. The PET process was studied using fluorescence lifetime decay, which confirmed the dynamic quenching of S,N-CQD fluorescence. The limit of detection (LOD) of S,N-CQDs in aqueous solution and the nanopaper-based sensor was 0.45 µM in the concentration range of 1-50 µM and 31.05 µM in the concentration range of 1-250 µM, respectively.

0D to 3D PrIII metal-organic networks crystal engineered for optimal iodine adsorption.

Four new praseodymium(III) metal-organic compounds varying in dimensionality from 0D to 3D have been designed and synthesized based on N-heterocyclic polycarboxylic acids, including pyridine-2,6-dicarboxylic acid (H2pydc) and pyrazine-2,3-dicarboxylic acid (H2pzdc). Altering the concentration of piperazine (pip, ancillary ligand) enables control over the dimensionality of the compound by switching between the 0D [H2pip][Hpip][Pr(pydc)3]·4H2O (I) and the 1D {[Pr(pydc)(Hpydc)(H2O)2]·4H2O}n (II) coordination polymer (CP). Upon replacing H2pydc with H2pzdc, CP II is converted to the 2D CP [Pr(pzdc)(Hpzdc)(H2O)3]n (III) and using the metalloligand [Zn(Hpzdc)2(H2O)2]2-, the 3D heterometallic CP {[Pr2Zn(pzdc)4(H2O)6]·2H2O}n (IV) is formed. Compound IV shows high stability in the absence of uncoordinated solvent molecules and is stable up to 400°C, even in the presence of humidity. Therefore, IV was utilized for iodine adsorption in the vapour phase and in the presence of humidity. The results confirm the remarkable potential of IV for reversible adsorption of iodine vapour.

Liquid Calibration Phantoms in Ultra-Low-Dose QCT for the Assessment of Bone Mineral Density.

INTRODUCTION: Cortical bone is affected by metabolic diseases. Some studies have shown that lower cortical bone mineral density (BMD) is related to increases in fracture risk which could be diagnosed by quantitative computed tomography (QCT). Nowadays, hybrid iterative reconstruction-based (HIR) computed tomography (CT) could be helpful to quantify the peripheral bone tissue. A key focus of this paper is to evaluate liquid calibration phantoms for BMD quantification in the tibia and under hybrid iterative reconstruction-based-CT with the different hydrogen dipotassium phosphate (K2HPO4) concentrations phantoms. METHODOLOGY: Four ranges of concentrations of K2HPO4 were made and tested with 2 exposure settings. Accuracy of the phantoms with ash gravimetry and intermediate K2HPO4 concentration as hypothetical patients were evaluated. The correlations and mean differences between measured equivalent QCT BMD and ash density as a gold standard were calculated. Relative percentage error (RPE) in CT numbers of each concentration over a 6-mo period was reported. RESULTS: The correlation values (R2 was close to 1.0), suggested that the precision of QCT-BMD measurements using standard and ultra-low dose settings were similar for all phantoms. The mean differences between QCT-BMD and the ash density for low concentrations (about 93 mg/cm3) were lower than high concentration phantoms with 135 and 234 mg/cm3 biases. In regard to accuracy test for hypothetical patient, RPE was up to 16.1% for the low concentration (LC) phantom for the case of high mineral content. However, the lowest RPE (0.4 to 1.8%) was obtained for the high concentration (HC) phantom, particularly for the high mineral content case. In addition, over 6 months, the K2HPO4 concentrations increased 25% for 50 mg/cm3 solution and 0.7 % for 1300 mg/cm3 solution in phantoms. CONCLUSION: The excellent linear correlations between the QCT equivalent density and the ash density gold standard indicate that QCT can be used with submilisivert radiation dose. We conclude that using liquid calibration phantoms with a range of mineral content similar to that being measured will minimize bias. Finally, we suggest performing BMD measurements with ultra-low dose scan concurrent with iterative-based reconstruction to reduce radiation exposure.

Synthesis of some transition metal (M: 25Mn, 27Co, 28Ni, 29Cu, 30Zn, 47Ag, 48Cd) sulfide nanostructures by hydrothermal method.

The design of nanostructures with favored shape, particle size and structure is one of the most important fields of nanoscience. To reach this target hydrothermal method is one of the most applicable methods which allow us to obtain favored structures by changing some parameters. This review focuses on synthesis of some transition metal sulfides by hydrothermal method because of technological importance of this group of material. The common sulfides of Mn, Co, Ni, Cu, Zn, Ag and Cd are introduced and a mechanism proposed for their synthesis. The effects of temperature and time reaction, surfactant, reactants concentration, metal and sulfur sources and etc. on the morphology, particle size and some properties of the products are investigated. SEM and TEM images show the morphology and size of the as-synthesized samples. Chemical composition of the samples is characterized by XRD, EDS and etc. The magnetic, optical and thermoelectric properties of the metal sulfides are investigated.

Sonochemical synthesis and characterization of NiMoO4 nanorods.

NiMoO(4) nanorods have been successfully synthesized by sonochemical method process by using Ni(CH(3)COO)(2) · 4H(2)O and (NH(4))(6)Mo(7)O(24) · 4H(2)O as starting materials. Some parameters including ultrasonic power, ultrasonic irradiation time, stirring effect, solvent effect, and surfactant effect were investigated to reach optimum condition. The as synthesized nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmittance electron microscopy (TEM), photoluminescence (PL) spectroscopy, Fourier transform infrared (FT-IR) spectra and energy dispersive X-ray microanalysis (EDX). Facile preparation and separation are important features of this route. This work has provided a general, simple, and effective method to control the composition and morphology of NiMoO(4) in aqueous solution, which will be important for inorganic synthesis methodology.