Determination of iodine and molybdenum in milk by quadrupole ICP-MS

A reliable method for the determination of iodine and molybdenum in milk samples, using alkaline digestion with tetramethylammonium hydroxide and hydrogen peroxide, followed by quadrupole ICP-MS analysis, has been developed and tested using certified reference materials. The use of He + O2 (1.0 ml min-1 and 0.6 ml min-1) in the collision-reaction cell of the mass spectrometer to remove 129Xe+ - initially to enable the determination of low levels of 129I - also resulted in the quantitative conversion of Mo+ to MoO2+ which enabled the molybdenum in the milk to be determined at similar mass to the iodine with the use of Sb as a common internal standard. In order to separate and pre-concentrate iodine at sub μg L-1 concentrations, a novel method was developed using a cation-exchange column loaded with Pd2+ and Ca2+ ions to selectively retain iodide followed by elution with a small volume of ammonium thiosulfate. This method showed excellent results for aqueous iodide solutions, although the complex milk digest matrix made the method unsuitable for such samples. An investigation of the iodine species formed during oxidation and extraction of milk sample digests was carried out with a view to controlling the iodine chemistry

Extractive Spectrophotometric Determination of Bismuth(III) in Water Using Some Ion Pairing Reagents

Two novel and low cost liquid-liquid extraction methods for the separation of bismuth(III) at trace level from aqueous medium have been developed. The two methods were based upon the formation of yellow colored ternary complex ion associates of tetraiodobismuth(III) complex anion, BiI4- with the ion-pairing reagent 2,3,5-tetraphenyltetrazoliumchloride (Tz+.Cl–) and 1, 10 phenanthroline (Phen) in sulfuric acid medium. The effect of various parameters e.g. pH, organic solvent, shaking time, etc. on the preconcentration of bismuth(III) from the aqueous media by the reagent was investigated. The developed colored complex ion associates [Tz+.BiI4-] and [Phen+.BiI4-] were extracted quantitatively into acetone-chloroform (1:1v/v) and methyliso- butylketone (MIBK), respectively. The compositions of the formed complex ion associates [Tz+.BiI4-] and [Phen+.BiI4-] were determined by the Job's method at 500 and 490 nm, respectively. The plots of bismuth(III) concentration (0-17 μg mL-1) versus absorbance of the associates at 500 and 490 nm were linear with good correlation coefficient (R2=0.998). The developed method of the ion associate [Tz+.BiI4-] two methods was applied successfully for the analysis of bismuth in water

Alpha-l-Fucosidase Immunoassay for Early Detection of Hepatocellular Carcinoma

Detection of alpha-l-fucosidase has been shown to have relevance in diagnosing hepatocellular carcinoma. Few assays have been developed to measure this enzyme, with most relying on colorimetric techniques involving the enzyme's kinetics. While these assays are facile and quick, the sensitivity is not always sufficient for early tumor detection. To improve upon previous assays for alpha-l-fucosidase, a fluorescence based immunoassay was produced implementing an alpha-l-fucosidase specific antibody (FUCA2). The immobilization of the alpha-l-fucosidase-specific antibody onto a quartz slide was investigated with several bioconjugation approaches and an immunoassay for detection of alpha-l-fucosidase was produced. The immunoassay was utilized to produce calibration curves for quantifying alpha-l-fucosidase concentrations in both PBS and human blood serum. A detection limit of 10 nM was found using human blood serum, which is well below the diagnostic cutoff point of 80 nM

Carbon dots: Biomacromolecule interaction, bioimaging and nanomedicine

This review summarizes the interactions of C-dots with biomacromolecules and the applications of C-dots in target-specific bioimaging and nanomedicine. [Display omitted] •The interaction of carbon dots with biomacromolecules and their corresponding applications are discussed.•The recent advancements of carbon dots in target-specific bioimaging are highlighted.•The applications of carbon dots for drug delivery and theranostics development are detailed.•Current challenges and future opportunities for carbon dots study are presented. Carbon dots, a recent member of the renowned carbon-based nanomaterials family, have attracted significant interest from various fields. The extraordinary properties, including excellent photoluminescence, high biocompatibility, and tunable surface functionalities as well as the abundant and inexpensive nature, have led to remarkable bioapplications in bioimaging, drug delivery, and theranostics development. In this article, studies on the interaction of C-dots with biomacromolecules are reviewed first, and recent developments of C-dots for target-specific bioimaging, drug delivery as well as theranostics development are highlighted and discussed

Hybrid Antibody–Aptamer Assay for Detection of Tetrodotoxin in Pufferfish

The marine toxin tetrodotoxin (TTX) poses a great risk to public health safety due to its severe paralytic effects after ingestion. Seafood poisoning caused by the consumption of contaminated marine species like pufferfish due to its expansion to nonendemic areas has increased the need for fast and reliable detection of the toxin to effectively implement prevention strategies. Liquid chromatography-mass spectrometry is considered the most accurate method, although competitive immunoassays have also been reported. In this work, we sought to develop an aptamer-based assay for the rapid, sensitive, and cost-effective detection of TTX in pufferfish. Using capture-SELEX combined with next-generation sequencing, aptamers were identified, and their binding properties were evaluated. Finally, a highly sensitive and user-friendly hybrid antibody–aptamer sandwich assay was developed with superior performance compared to several assays reported in the literature and commercial immunoassay kits. The assay was successfully applied to the quantification of TTX in pufferfish extracts, and the results obtained correlated very well with a competitive magnetic bead-based immunoassay performed in parallel for comparison. This is one of the very few works reported in the literature of such hybrid assays for small-molecule analytes whose compatibility with field samples is also demonstrated.info:eu-repo/semantics/publishedVersio

Study of the Alpha‑l‑Fucosidase Langmuir Monolayer at the Air–Water Interface

Alpha-l-fucosidase is a known biomarker for hepatocellular carcinoma that has shown great potential in diagnostics. Most of the focus for this enzyme has been on the free form found in serum; however, little is known of the properties of the minor portion of membrane-bound alpha-l-fucosidase. To better understand the properties of membrane-bound alpha-l-fucosidase, this enzyme was surveyed at the air–water interface. Alpha-l-fucosidase is able to form a stable Langmuir monolayer, which was confirmed through surface-pressure and surface-potential area isotherms, as well as infrared reflection–absorption spectroscopy (IRRAS). Furthermore, an interaction between the alpha-l-fucosidase Langmuir monolayer and a specific antibody for this enzyme, FUCA2, was observed

Carbon dots and gold nanoparticles based immunoassay for detection of alpha-L-fucosidase

Hepatocellular carcinoma (HCC) is among the leading causes of mortality in the world. The detection of HCC in its early stage is the key for early treatment and thus the improvement of the chances of survival. Among the various methods of HCC screening, assays based on the detection of biomarker that is specific to HCC such as alpha-l-fucosidase (AFU) have been regarded as the most prominent methods. In this regards, a new assay for the detection of AFU to screen HCC was developed. This assay was based on the energy transfer between carbon dots (C-dots) and gold nanoparticles (AuNPs), the concentration of AFU could be monitored by the degree of C-dots fluorescence quenching due to the energy transfer. With this assay, a limit of detection of 3.4 nM (well below the diagnostic cutoff point of 80 nM), and a broad linear range of detection from 11.3 to 200 nM were achieved. We also demonstrate the determination of the concentration of AFU in human blood serum. [Display omitted] •Energy transfer between carbon dots and AuNPs was used to design assay for the detection of alpha-l-fucosidase.•A sandwich assay was designed by combining polyclonal antibody coated AuNPs with monoclonal antibody attached to carbon dots.•A limit of detection of 3.4 nM and linear range from 11.3 to 200 nM were achieved

“Dark” carbon dots specifically “light-up” calcified zebrafish bones

Because accidents, disease and aging compromise the structural and physiological functions of bones, the development of an in vivo bone imaging test is critical to identify, detect and diagnose bone related development and dysfunctions. Recent advances in fluorescence instrumentation offer a new alternative for traditional bone imaging methods. However, the development of new in vivo bone imaging fluorescence materials has significantly lagged behind. Here we show that carbon dot nanoparticles (C-dots) with low quantum yield (“dark”) bind to calcified bone structures of live zebrafish larvae with high affinity and selectivity. Binding resulted in a strong enhancement of luminescence that was not observed in other tissues, including non-calcified endochondral elements. Retention of C-dots by bones was very stable, long lasting, and with no detectable toxicity. Furthermore, we found C-dots to be a suitable carrier to deliver fluorescein to bones. These observations support a novel and revolutionary use of C-dots as highly specific bioagents for bone imaging and diagnosis, and as bone-specific drug delivery vehicles

Pediatric glioblastoma target-specific efficient delivery of gemcitabine across the blood–brain barrier via carbon nitride dots

Pediatric glioblastomas are known to be one of the most dangerous and life-threatening cancers among many others regardless of the low number of cases reported. The major obstacles in the treatment of these tumors can be identified as the lack of prognosis data and the therapeutic requirement to be able to cross the blood–brain barrier (BBB). Due to this lack of data and techniques, pediatric patients could face drastic side effects over a long-time span even after survival. Therefore, in this study, the capability of non-toxic carbon nitride dots (CNDs) to selectively target pediatric glioblastoma cells was studied in vitro. Furthermore, the nanocarrier capability and efficiency of CNDs were also investigated through conjugation of a chemotherapeutic agent and transferrin (Tf) protein. Gemcitabine (GM) was introduced into the system as a chemotherapeutic agent, which has never been successfully used for the treatment of any central nervous system (CNS) cancer. More than 95% of selective damage of SJGBM2 glioma cells was observed at 1 μM of CN–GM conjugate with almost 100% viability of non-cancerous HEK293 cells, although this ability was diminished at lower concentrations. However, further conjugation of Tf to obtain CN–GM–Tf allowed the achievement of selective targeting and prominent anti-cancer activity at a 100-fold lower concentration of 10 nM. Furthermore, both conjugates were capable of effectively damaging several other brain tumor cells, which were not well responsive towards the single treatment of GM. The capability of BBB penetration of the conjugates was observed using a zebrafish model, which confirms the CNDs’ competence as an excellent nanocarrier to the CNS