Povlsensmed0999

A unique electrochemical sensor was constructed based on designed peptide hydrogels loaded with ciprofloxacin and gold nanoparticles, which exhibited excellent biocompatibility, antibacterial capability and electrochemical catalytic property. The peptide hydrogel was prepared base on the self-assembly of a designed short peptide sequence of Phe-Glu-Lys-Phe (FEKF) with the N-terminal modified with a fluorene methoxycarbonyl (Fmoc) group. The peptide hydrogel possessed nanofibrous network structure and exhibited good shear-thinning behavior and excellent biocompatibility, and it can be easily doped with gold nanoparticles and the antibiotic drug ciprofloxacin. The loaded antibacterial drug offered remarkable antibacterial activity of the hydrogel, while the loaded gold nanoparticles rendered the hydrogel excellent electrochemical catalytic capability towards the detection of a typical neurotransmitter dopamine. The combination of the antibacterial property and the electrochemical catalytic ability within a peptide hydrogel ensured the development of sensitive and antibacterial electrochemical sensors, and this strategy was expected to promote the construction of implantable sensors without infection.The deprotonation degree of the lipophilic pH indicator dye (chromoionophore) in ionophore-based ion optodes (so-called bulk optodes) has traditionally been measured spectrophotometrically. This makes it difficult to obtain spatially resolved concentration information, for example in the study of heterogenous systems. This article reports on a new colorimetric method that relies on a ratiometric image analysis. The acquision of image data allows one to map the deprotonation degree in two dimensions, which in turn is used to obtain the spatially-resolved ion concentration of the image. Using the detection of potassium as an example, the deprotonation degree data calculated on the basis of image analysis correlate quantitatively with those from spectrophotometry. They showed no dependence on the type of camera used in spite of their different gamma correction values and spectral sensitivities, as expected from theory. As an example, the method is successfully applied to the pixel level analysis of an ensemble of pictures acquired at different times to spatially and temporally observe potassium ion diffusion into an agarose gel containing a potassium-selective optical sensor microemulsion.SUMOylation is a reversible post-translational modification that plays crucial roles in numerous cellular processes. Although anti-SUMO antibodies have been applied to analyze exogenous and endogenous SUMOylation, such immunoprecipitation enrichment strategy is applicable only for the enrichment of one specific SUMO type in mammalian cells, unable to map the global landscape of all endogenous SUMOylation simultaneously. To address this issue, we proposed an antibody-free strategy to enrich and profile endogenous SUMO1/2/3-modified peptides simultaneously. Upon trypsin digestion, the SUMO1- and SUMO2/3-modified peptides contained SUMO remnants with 7 and 9 acidic amino acids respectively, which carried more negative charges at high pH and could interact with strong anion exchange (SAX) materials more strongly than non-SUMOylated peptides, thus enabling the specific enrichment of endogenous SUMOylated peptides. Followed by the secondary digestion with Asp-N/Glu-C to generate smaller SUMOylated peptides with proper length for MS identification, off-line high-pH C18 pre-fractionation and low pH nanoRPLC-ESI-MS/MS analysis, 177 SUMO1-modified sites and 74 SUMO2/3-modified sites were unbiasedly identified in HeLa cell lysate. To the best of our knowledge, this was the first antibody-free strategy to comprehensively profile various endogenous SUMOylation sites, demonstrating the great potential in the comprehensive analysis of endogenous SUMOylation across various species and organs, which might further facilitate the understanding of SUMO's function in physiology and pathology.In this study, we developed an integrated plasma proteome sample preparation system, by which high-abundance proteins from human plasma were first depleted by immunoaffinity column, followed by on-line middle and low-abundance proteins denaturation, reduction, desalting and tryptic digestion. To evaluate the performance of such a system, 20 μL plasma was processed automatically, followed by 1-h gradient liquid chromatography-mass spectrometry analysis (LC-MS). Compared to conventional in-solution protocols, not only the sample preparation time could be shortened from 20 h to 20 min, but also the number of identified proteins were greatly increased by 1.4-2.0 times. Such an integrated system allows us to process 36 human plasma samples per day, with more than 300 proteins and 52 FDA approved disease markers per sample being identified. With combination of such an integrated sample preparation system with label-free single-shot LC-MS/MS, the human plasma proteins could be quantified across more than 6 orders of magnitude of abundance range with high reproducibility (Pearson R = 0.99, n = 9). In addition, the relative quantification of human plasma samples from diabetic retinopathy patients and diabetic patients demonstrated the feasibility of our developed workflow for clinic plasma proteome profiling. All these results demonstrated that our developed integrated plasma proteome sample preparation system would provide a new tool for high throughput biomarker discovery.Polyacrylamide or agarose gels are the most frequently used sieving and stabilizing media in slab gel electrophoresis. Recently, we have introduced a new electrophoretic technique for concentration/separation of milliliter sample volumes. In this technique, the gel is used primarily as an anticonvection media eliminating liquid flow during the electromigration. While serving well for the liquid stabilization, the gels can undergo deformation when exposed to a discontinuous electrolyte buffer system used in epitachophoresis. In this work, we have explored 3D printing to form rigid stabilizing manifolds to minimize liquid flow during the epitachophoresis run. The whole device was printed using the stereolithography technique from a low water-absorbing resin. The stabilizing manifold, serving as the gel substitute, was printed as a replaceable composite structure preventing electrolyte mixing during the separation. Different geometries of the 3D printed stabilizing manifolds were tested for use in concentrating ionic sample components without spatial separation. The presented device can focus analytes from 3 or 4 mL of the sample to 150 μL or less, depending on the collection cup size. SH-4-54 datasheet With the 150 μL collection cup, this represents the enrichment factor from 20 to 27. The time of concentration was from 15 to 25 min, depending on stabilization media and power used.Exposure to chemical hazards is a growing concern in today's society, and it is of utmost interest to know the levels of exposure to chemicals and the risks associated with such exposure in order to implement effective health prevention strategies. Chemical risk analysis represents a complex and laborious task due to the large number of known substances, but also unknown compounds and emerging risks that must be addressed. In this challenging scenario, the study of metabolic perturbations induced by exposure to a given chemical hazard has recently emerged as an interesting alternative approach to apply in chemical risk analysis. Specifically, the biomarkers of effect identified by metabolomics are expected to reveal the adverse effects of chemicals and further link exposure to disease development. In this context, analytical chemistry has become an essential part of the strategy to highlight such biomarkers. The corollary is that the relevance of the discovered biomarkers will largely depend on both the quality of the analytical approaches implemented and the part of the metabolome covered by the analytical technique used. This review focuses on describing significant applications of metabolomics in the field of chemical risk analysis. The different risk assessment steps, including hazard identification, dose-response assessment and exposure assessment, and risk management are addressed through various examples to illustrate that such an approach is fit-for-purpose and meets the expectations and requirements of chemical risk analysis. It can be considered as an innovative tool for predicting the probable occurrence and nature of risks, while addressing the current challenges of chemical risk analysis (e.g. replacement, reduction and refinement (3R) of animal testing, effects of exposure to chemical mixtures at low doses, etc.), and with the aim of responding to chemical exposures concerns in a holistic manner and anticipating human health problems.By the employment of a homogeneous biorecognition reaction to induce the assembled formation of DNA nanostructures at an electrode, herein we develop a novel biosensing method for the ultrasensitive electrochemical detection of kanamycin (Kana) antibiotic. A DNA complex consisting of Kana-aptamer and a hairpin DNA with an exposed 3'-end was first designed for conducting the homogeneous reaction with Kana in the presence of exonuclease I (Exo I). It resulted in the production of a hairpin DNA with a blunt terminus, which could be used for triggering the assembled formation of a layer of DNA nanostructures with orderly distribution and abundant biotin sites at a gold electrode. Then, high-content methylene blue and horseradish peroxidase (HRP)-functionalized gold nanotags would be captured onto the electrode to realize the electrocatalytic signal transduction. Due to the Exo I and HRP-assisted dual signal amplification, a very low detection limit of 9.1 fg mL-1 was obtained for the Kana assay along with a very wide linear range over five-order of magnitude. Considering the excellent performance of the method, it exhibits a promising prospect for practical applications.We report a new highly selective detection platform for human albumin (HA) in urine based on aptamer-functionalised magnetic particles. Magnetic separation and re-dispersion was utilised to expose the HA-bound particles to a methylene blue solution. A second magnetic collection step was then used to allow the methylene blue supernatant to be reduced at an unmodified screen-printed electrode. Since methylene blue adsorbs to HA, the reduction current fell in proportion to HA concentration. There was no interference from compounds such as dopamine, epinephrine, vanillylmandelic acid, normetanephrine, metanephrine and creatinine in artificial urine at the concentrations at which they would be expected to appear. A calibration equation was derived to allow for the effect of pH on the response. This enabled measurement to be made directly in clinical urine samples of varying pH. After optimisation of experimental parameters, the total assay time was 40 min and the limit of detection was between 0.93 and 1.16 μg mL-1, depending on the pH used. HA could be detected up to 400 μg mL-1, covering the range from normoalbuminuria to macroalbuminuria. Analysis of urine samples of patients, with diabatic nephropathy, type I & II diabetes mellitus and chronic kidney disease, from a local hospital showed good agreement with the standard urinary human albumin detection method.