One-pot hydrothermal synthesis of a carbon quantum dot/CaFe2O4 hybrid nanocomposite for carcinogenic Congo red dye degradation.

Semiconductor materials show a restricted degradation response to organic pollutants due to limited photocatalytic activity under visible light. Therefore, researchers have devoted much attention to novel and effective nanocomposite materials. For the first time, herein, a novel nano-sized semiconductor calcium ferrite modified by carbon quantum dots (CaFe2O4/CQDs) photocatalyst is fabricated via simple hydrothermal treatment for the degradation of aromatic dye using a visible light source. The crystalline nature, structure, morphology, and optical parameters of each of the synthesized materials were investigated using X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and UV-visible spectroscopy. The nanocomposite exhibits excellent photocatalytic performance (90% degradation) against Congo red (CR) dye. In addition, a mechanism for CaFe2O4/CQDs improving photocatalytic performance has been proposed. The CQDs in the CaFe2O4/CQD nanocomposite are considered to act as an electron pool and transporter, as well as a strong energy transfer material, during photocatalysis. CaFe2O4/CQDs appear to be a promising and cost-effective nanocomposite for dye-contaminated water purification, according to the findings of this study.

Tin derived antimony/nitrogen-doped porous carbon (Sb/NPC) composite for electrochemical sensing of albumin from hepatocellular carcinoma patients.

An electrochemical sensor based on an antimony/nitrogen-doped porous carbon (Sb/NPC) composite has been developed for the quantitative detection of albumin from hepatocellular carcinoma (HCC) patients. Sb/NPC is hydrothermally synthesized from Sn/NPC precursors. The synthesized precursor (Sn/NPC) and the product (Sb/NPC) are characterized by XRD, FTIR, TGA, UV/Vis, SEM, and AFM. Cyclic voltammetry, chronoamperometry, and electrochemical impedance studies are used to investigate the electrochemical performance of Sb/NPC-GCE. Sb/NPC-GCE detects albumin at physiological pH of 7.4 in the potential range 0.92 V and 0.09 V for oxidation and reduction, respectively. LOD and recovery of Sb/NPC-GCE for the determination of albumin are 0.13 ng.mL-1 and 66.6 ± 0.97-100 ± 2.73%, respectively. Chronoamperometry of the modified working electrode demonstrates its stability for 14 h, indicating its reusability and reproducibility. Sb/NPC-GCE is a selective sensor for albumin detection in the presence of interfering species. The electrode has been applied for albumin detection in human serum samples of HCC patients. A negative correlation of albumin with alpha-fetoprotein levels in HCC patients is observed by statistical analysis.

Graphene oxide-metal oxide nanocomposites for on-target enrichment and analysis of phosphorylated biomolecules.

The surface of matrix-assisted laser desorption/ionization mass spectrometry target is modified for improved signal strength and detection of analytes. The developed method includes on-target enrichment and detection of phosphopeptides/phospholipids using graphene oxide-lanthanide metal oxides (samarium, gadolinium, dysprosium, and erbium) nanocomposites. Enriched phosphopeptides are detected using material enhanced laser desorption/ionization mass spectrometry and phospholipids by laser desorption/ionization-mass spectrometry. Nanocomposites are prepared using graphene oxide with respective metal salts at high pH. They are characterized for nano-morphology, chemistry, porosity, composition, crystallinity, and thermal stability. Phosphopeptides enrichment protocol is developed and optimized for tryptic ß-casein digest and that of phospholipids by phosphatidylcholine standard. Statistical analyses of phosphopeptides and phospholipids from milk show overlapping results for gadolinium, dysprosium, and erbium oxide nanocomposites. GO-Gd2 O3 has better enrichment efficiency and application as LDI material. Selectivity for GO-Dy2 O3 is 1:2500, for GO-Sm2 O3 is 1:3500, and 1:4000 for GO-Gd2 O3 . GO-Er2 O3 has a sensitivity of 25 fmol, whereas the highest sensitivity is down to 0.5 fmol for GO-Gd2 O3 . On-target enrichment is batch to batch reproducible with a standard deviation of <1, reduced time of enrichment to 10 min, and ease of operation compared to solid-phase batch extraction. The developed method enriches serum phosphopeptides characteristic of cancer-related phosphoproteins.

Quantitative determination of creatinine from serum of prostate cancer patients by N-doped porous carbon antimony (Sb/NPC) nanoparticles.

Creatinine is an indicator of hindrance in urination and renal insufficiency. Creatinine levels are the marker of the late stages of prostate cancer. Early and sensitive detection of creatinine can reduce deaths associated with prostate cancer. In this work, nitrogen-doped porous carbon antimony (Sb/NPC) nanoparticles are fabricated to be employed as a non-enzymatic biosensor. Sb/NPC has promising redox activity and is synthesized by a two-step reaction using low-cost precursors. Electrochemical sensing by Sb/NPC is conducted for standard creatinine solutions on a three-electrodes system. Cyclic voltammetry, amperometry, and electrochemical impedance spectroscopy are used to sense creatinine. LOD and LOQ of the Sb/NPC modified electrode are 0.74 µM and 2.4 µM, respectively. This electrode system analyzes creatinine in the serum of prostate cancer patients who have elevated PSA levels. More than 90% creatinine is recovered from a spiked serum sample of a prostate cancer patient. A direct relation is observed between PSA levels and creatinine levels in prostate cancer. The developed cyclic voltammetric setup detects trace concentrations of creatinine in serum.

Bimetallic cobalt-iron diselenide nanorod modified glassy carbon electrode: an electrochemical sensing platform for the selective detection of isoniazid.

The increasing demand of a sensitive and portable electrochemical sensing platform in pharmaceutical analysis has developed widespread interest in preparing electrode materials possessing remarkable properties for the electrochemical determination of target drug analytes. Herein, we report the synthesis, characterization and application of bimetallic cobalt-iron diselenide (FeCoSe2) nanorods as electrode modifiers for the selective detection of a commonly used anti-tuberculosis drug Isoniazid (INZ). We prepared FeCoSe2 nanorods by a simple hydrothermal route and characterized these by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and temperature-programmed reduction (TPR) techniques. The electrochemical characterization of FeCoSe2 modified GCE was performed by cyclic voltammetry (CV) and square wave anodic stripping voltammetry (SWASV). Under optimized experimental conditions, a linear current-concentration response was obtained for INZ in the range of 0.03-1.0 µM, with very low limit of detection 1.24 × 10-10 M. The real applicability of the designed FeCoSe2/GCE sensing platform was adjudicated by the detection of INZ in biological samples.

Tellurium doped zinc imidazole framework (Te@ZIF-8) for quantitative determination of hydrogen peroxide from serum of pancreatic cancer patients.

The tellurium doped zinc imidazole framework (Te@ZIF-8) is prepared by a two-step hydrothermal strategy for the electrochemical sensing of hydrogen peroxide. Material is characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The electrochemical characterization of the MOF modified electrode is done by a three-electrode system. Electrochemical sensing of hydrogen peroxide is made by cyclic voltammetry, amperometry, and impedance measurements. Results demonstrate that Te@ZIF-8 shows a detection limit of 60 µM with linearity up to 0.98855. Material is stable to 1000 cycles with no significant change in electrochemical response. Amperometry depicts the recovery of hydrogen peroxide from human serum up to 101%. Impedance curve reveals the surface of Te@ZIF-8-GCE (glassy carbon electrode) as porous and rough and an interface is developed between analyte ions and the sensing material. Finally, the modified electrode is used for the quantitative determination of hydrogen peroxide from serum samples of pancreatic cancer patients, diagnosed with CA 19-9.

Catalase immobilized antimonene quantum dots used as an electrochemical biosensor for quantitative determination of H2O2 from CA-125 diagnosed ovarian cancer samples.

A selective and cost-effective biosensor based on catalase immobilized antimonene quantum dots modified glassy carbon electrode (Cat@AMQDs-GCE) is designed for the first time to determine hydrogen peroxide (H2O2). Antimonene quantum dots (AMQDs) are synthesized by a single step method, characterized by various analytical techniques and applied to the electrochemical sensing of hydrogen peroxide. Catalase enzyme specific for H2O2 reduction is immobilized onto AMQDs to facilitate its detection by cyclic voltammetry and amperometry. Concentration, scan rate, pH, stability and selectivity are optimized. Linearity of Cat@AMQDs-GCE is determined as 0.989 with limit of detection as 4.4 µM. Amperometric measurements show recovery of 95 to 103.4% for H2O2 from human serum samples. Cat@AMQDs-GCE is electrochemically stable up to 30 cycles, reducing the cost of analysis. Cat@AMQDs-GCE shows good selectivity in presence of ascorbic acid, dopamine, leucine and glucose. Prepared electrode is also applied for the quantitative determination of H2O2 from ovarian cancer serum. CA 125 concentration is previously determined by Elecsys CA 125 II Assay. Results demonstrate that concentration of H2O2 increases with increasing levels of CA125 in serum.

Gallic acid functionalized UiO-66 for the recovery of ribosylated metabolites from human urine samples.

Early diagnosis of disease biomarkers has been focused in recent years through Omics sciences. Nucleosides are the biomarkers of cancers including lung cancer, colorectal cancer, thyroid cancer, bladder cancer, cervical cancer and breast cancer. Nucleosides are directly excreted in the urine of diseased states whereas they are decomposed into other forms as modified nucleosides in healthy conditions. A dual affinity probe (gallic acid modified UiO-66) is prepared and reported for the first time in selectively enriching the ribosylated metabolites and modified nucleosides. Material is characterized by SEM, EDX, FTIR and Nitrogen adsorption porosimetry. The enrichment is benefitted from the interaction ability of zirconium towards glycosylated molecules, rich surface chemistry (3 terminal hydroxyl groups) on gallic acid and high surface area (384 m2/g) of 3-dimensional porous structure of metal organic frameworks (MOFs). Material shows selectivity of 1:500, recovery up to 137.1% and binding capacity of 2340.9 µg/g. Forty-three (43) nucleosides are enriched from human urine samples and 12 potential nucleoside biomarkers from colorectal cancer samples are quantified and their concentration is found higher than in the healthy controls.

Alumina nanocomposites: a comparative approach highlighting the improved characteristics of nanocomposites for phosphopeptides enrichment.

The work is based on the comparative study of metal oxide nanocomposites based on alumina in combination with two transition metal oxides (zirconia and titania) and two lanthanide oxides (ceria and lanthanum oxide). The choice is based on specific aims, i.e. to improve the limitations of individual metal oxides in phosphopeptide enrichment. The nanocomposites have shown improved phosphopeptide enrichment efficiency in comparison to the individual metal oxides. Alumina-zirconia show enhanced mono-phosphorylated peptide enrichment than ZrO2 whereas alumina-titania has better recovery of mono- and multi-phosphorylated peptides in comparison to individual TiO2. Alumina-ceria and alumina-lanthanum oxide overall enrich higher number of phosphopeptides. The alumina nanocomposites show higher selectivity and sensitivity for spiked ß-casein in BSA (1:1000) and diluted ß-casein digest (10 femtomole), respectively. Through the transition metal oxide nanocomposites, number of phosphoproteins from human serum are identified while this number is highest in case of alumina-lanthanum oxide nanocomposite. Thus the enrichment is affected by the choice of metal oxide in the nanocomposite based enrichment strategies.

Newly developed poly(allyl glycidyl ether/divinyl benzene) polymer for phosphopeptides enrichment and desalting of biofluids.

The polymeric materials have contributed significantly in the area of bioanalytical science. The functionalization of polymeric backbone after its development brings unique selectivity towards the target biomolecules. In present work, the functionalities of choice have been introduced through the ring-opening of allyl glycidyl ether. The utility of polymer is widened through derivatizations to immobilized metal ion affinity chromatographic (IMAC) material for the phosphopeptides enrichment and Reversed Phase (C-18) for the desalting prior to MALDI-MS analysis. The polymer-IMAC in addition to Fe(3+) is also immobilized with lanthanide ions like La(3+), Eu(3+), and Er(3+). The amount of Fe(3+) immobilized is determined as 0.7928 mg/g. Spherical morphology with narrow particle size dispersion is revealed by scanning electron microscopy (SEM). The surface area, pore volume and size distribution is determined by nitrogen adsorption porosimetery. The elemental composition and purity level is confirmed by energy dispersive X-ray spectroscopy (EDX) data. The derivatization to IMAC and RP is evaluated by Fourier transform infrared (FT-IR) spectroscopy. The polymer enables the efficient phosphopeptide enrichment to equal degree from casein variants, non-fat milk, egg yolk, human serum, and HeLa cell extract. The identification of phosphorylation sites can lead to the phosphorylation pathways to understand the post-translational modifications. The identification with their sequence coverage is made using Mascot and Phosphosite Plus. It is sensitive to enrich the phosphopeptides down to 2 femtomoles with very high selectivity of 1:2000 with BSA background. These attributes are linked to the higher surface area (173.1554 m(2)/g) of the designed polymer. The non-specific bindings, particularly the Fe(3+) linked acidic residues are also avoided. Four characteristic phosphopeptides (fibrinopeptide A and their hydrolytic products) from fibrinogen α-chain are identified from the human serum after the enrichment, which have link to the hepatocellular carcinoma (HCC). The proportions of fibrinogen and their phosphorylation products enriched by poly(AGE/DVB)-IMAC open new horizons in the biomarker discovery.