Fluorescence Spectrophotometer Research Articles

Dual signal AA detection based on fluorescence and local surface plasmon resonance absorption technology

The core/shell Au@MnO2 nanoparticles (Au@MnO2 NPs) were prepared and characterized by UV–vis spectrum, transmission electron microscopy (TEM) and X-ray photoelectron spectrum (XPS). It was found that MnO2 in the shell of Au@MnO2 NPs could oxidize thiamine (VB1) into blue fluorescent thiochrome (TC). The reduction of MnO2 in the shell layer could lead to a decrease of Au@MnO2 NPs size along with a blue shift of the localized surface plasmon resonance (LSPR) peak. Once ascorbic acid (AA) was introduced, MnO2 in the shell was rapidly reduced to Mn2+ ions. Accordingly, the oxidation of VB1 was inhibited and the fluorescence of TC was weakened. Based on these phenomena, we have established a dual signal method for AA determination with the help of UV–vis and fluorescence spectrophotometer. Under the optimum conditions, the LSPR absorption peak shift (Δλ) of Au@MnO2 NPs and the decrease in fluorescence of TC correlated well with AA concentration ranging from 0.75 to 17.5 μM. The detection limits of LSPR absorption assay and fluorescence assay were 0.18 and 0.47 μM, respectively. More importantly, this dual-signal detection method has been used for the determination of AA in vitamin C tablets with high accuracy and precision, indicating its promising potential applications.

Synthesis of Spherical Na(La, RE)(MoO4)2 (RE = Eu/Yb, Er), Up/Down Conversion Photoluminescence and Optical Thermometry

In this work, spherical Na(La,RE)(MoO[Formula: see text] (RE = Eu/Yb-Er) double molybdates were prepared using the rare earth hydroxide (La,RE)(OH)SO4 as a self-sacrificing template. The composition, structure, morphology, up/down conversion luminescence and fluorescence lifetime (FL) of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), fluorescence spectrophotometer, and Fourier transform infrared (FT-IR) spectrophotometer. The results indicate that highly pure spherical Na(La,RE)(MoO[Formula: see text] (RE = Eu/Yb-Er) samples can be obtained from the proposed route. The room temperature and temperature-dependent up/down conversion luminescence properties of the resulting Na(La,RE)(MoO[Formula: see text] (RE = Eu/Yb-Er) phosphors were analyzed in detail. The temperature-sensing performances for the two phosphors in both fluorescence intensity ratio (FIR) and FL modes were evaluated. Classical down and up-conversion photoluminescence (PL) from Eu[Formula: see text] and Er[Formula: see text] were observed. The down conversion phosphors were proved to be capable of sensing temperature via FL mode, and the maximum absolute sensitivity (SA) and maximum relative sensitivity (SR) were found to be [Formula: see text][Formula: see text]K[Formula: see text] (298[Formula: see text]K) and [Formula: see text][Formula: see text]K[Formula: see text] (523[Formula: see text]K), respectively. The up conversion phosphors Na(La,Yb,Er)(MoO[Formula: see text] were well capable of sensing temperature via FIR mode through thermally coupled 2H[Formula: see text], 4S[Formula: see text] levels (I[Formula: see text]/I[Formula: see text], and the maximum absolute sensitivity (SA) and maximum relative sensitivity (SR) were found to be [Formula: see text][Formula: see text]K[Formula: see text] (523[Formula: see text]K) and [Formula: see text][Formula: see text]K[Formula: see text] (348[Formula: see text]K), respectively.

A Smartphone-Integrated Molecularly Imprinted Fluorescence Sensor for Visual Detection of Chlortetracycline Based on N,P-Codoped Carbon Dots Decorated Iron-Based Metal-Organic Frameworks.

The residue of chlortetracycline is potentially hazardous to human health; it is meaningful to exploit a portable, rapid, sensitive, and selective method for detection of chlortetracycline (CTC). In this study, a novel fluorescence bionic sensing probe (NH2-MIL-53&N,P-CDs@MIP) was successfully prepared based on the nitrogen and phosphorus codoped carbon dots decorated iron-based metal-organic frameworks combining with molecular imprinted polymer for the detection of CTC. A fluorescence intensity-responsive "on-off" detection of CTC on account of the inner-filter effect (IFE) was achieved by NH2-MIL-53&N,P-CDs@MIP. Under the optimal conditions, the fluorescence quenching degree of NH2-MIL-53&N,P-CDs@MIP presented a good linear relationship with the CTC concentration in the range 0.06-30 μg mL-1 and the limit of detection (LOD) was 0.019 μg mL-1. The fluorescent probe was applied to detect CTC in milk samples, and experimental results showed a good recovery rate (88.73%-96.28%). Additionally, a smartphone-integrated fluorescence sensing device based on NH2-MIL-53&N,P-CDs@MIP was exploited to replace the expensive and bulky fluorescence spectrophotometer for quantitative determination of CTC with the LOD of 0.033 μg mL-1. The sensing system showed high selectivity, strong stability, high specificity, and portability, which provide a great strategy for the quantitative detection of antibiotic residue.

Influence of Pasteurization on Maillard Reaction in Lactose-Free Milk.

In order to improve the safety and quality of lactose-free milk (LFM) Maillard reaction products (MRPs), this study used raw cow's milk as raw material and lactase hydrolysis to prepare LFM, which was heat-treated using pasteurization and then placed in storage temperatures of 4 °C, 25 °C and 37 °C to investigate the changes in the Maillard reaction (MR). The results of the orthogonal test showed that the optimal conditions for the hydrolysis of LFM are as follows: the hydrolysis temperature was 38 °C, the addition of lactase was 0.03%, and the hydrolysis time was 2.5 h. Under these conditions, the lactose hydrolysis rate reached 97.08%, and the lactose residue was only 0.15 g/100 g as determined by high-performance liquid chromatography (HPLC), complying with the standard of LFM in GB 28050-2011. The contents of furoamic acid and 5-hydroxymethylfurfural were determined by high-performance liquid chromatography, the color difference was determined by CR-400 color difference meter, and the internal fluorescence spectrum was determined by F-320 fluorescence spectrophotometer. The test results showed that the variation range of furosine in lactose-free milk after pasteurization was 44.56~136.45 mg/100g protein, the range of 5-hydroxymethylfurfural (HMF) was 12.51~16.83 mg/kg, the color difference ranges from 88.11 to 102.53 in L*, from -0.83 to -0.10 in a*, and from 1.88 to 5.47 in b*. The furosine content of LFM during storage at 4, 25, and 37 °C ranged from 44.56 to 167.85, 44.56 to 287.13, and 44.56 to 283.72 mg/100 g protein, respectively. The average daily increase in protein content was 1.18-3.93, 6.46-18.73, and 15.7-37.66 mg/100 g, respectively. The variation range of HMF was 12.51~17.61, 12.51~23.38, and 12.51~21.1 mg/kg, and the average daily increase content was 0.03~0.07, 0.47~0.68, and 0.51~0.97 mg/kg, respectively. During storage at 4 °C, the color difference of LFM ranged from 86.82 to 103.82, a* ranged from -1.17 to -0.04, and b* ranged from 1.47 to 5.70. At 25 °C, color difference L* ranges from 72.09 to 102.35, a* ranges from -1.60 to -0.03, b* ranges from 1.27 to 6.13, and at 37 °C, color difference L* ranges from 58.84 to 102.35, a* ranges from -2.65 to 1.66, and b* ranges from 0.54 to 5.99. The maximum fluorescence intensity (FI) of LFM varies from 131.13 to 173.97, 59.46 to 173.97, and 29.83 to 173.97 at 4, 25, and 37 °C. In order to reduce the effect of the Maillard reaction on LFM, it is recommended to pasteurize it at 70 °C-15 s and drink it as soon as possible during the shelf life within 4 °C.

Fluorescence of Esthetic Resin Composites: Spectrophotometry and Photography Analysis Techniques.

The aim of this study was to evaluate the fluorescence of nine esthetic resin composite materials using two methods: spectrophotometry and photography analysis. Three specimens were made for each shade of resin composite (61 shades from 9 resin composites), for a total of 183 specimens. To obtain a control group, the crowns of three sound human incisors were prepared to obtain both enamel and dentin specimens. Fluorescence was measured using two methods: (1) a Spectroshade Micro fluorescence spectrophotometer (MHT Optic Research, Niederhasli, Switzerland) and (2) a photograph analysis using Adobe Photoshop CC software (version 2019.0.0, Adobe Systems, Inc.). The results were statistically analyzed with an analysis of variance (α = 0.05) and with the Tukey-Kramer adjustment. The correlation between two techniques was analyzed by Pearson correlation test (α = 0.05). Fluorescence was highly influenced by the brand of the resin composite and less influenced by the shade (chroma), except for opaquer and incisal shades, and there was almost no difference in opacity, except for incisal shades. There was a weak (r = -0.105) and statistically not significant correlation (p = 0.145) between photography analysis and spectrophotometry techniques. The fluorescence of esthetic resin composites is more dependent on the brand than on the shade or opacity.

Exploring the Potential of Azo Compounds in Leukemia Treatment: Synthesis and Characterization of New Derivatives with Dimedone and Meldrum's Acid End Groups

AbstractThis scholarly investigation presents pioneering drug candidates for combating leukemia, distinguished by reduced side effects and elevated efficacy. The study focuses on azo compounds for their selective targeting against cancerous cells, and customizable properties. Novel azo compounds, DMTPC and DMTPD, were skillfully synthesized via diazotization of 3‐(4‐Methyl‐1H‐imidazol‐1‐yl)‐5‐(trifluoromethyl)aniline with dimedone and meldrum‘s acid. Comprehensive characterization employed advanced analytical techniques like 1H‐NMR, 13C‐NMR, LC‐MS, FT‐IR, and XRD. UV‐Vis and fluorescence spectrophotometers scrutinized absorption and fluorescence properties in diverse solvents. Theoretical DFT computations provided optimized geometries, vibrational frequencies, NMR chemical shifts, absorption wavelengths, HOMOs‐LUMOs, Mulliken charges, and molecular orbital energies. Encouragingly, experimental and theoretical values aligned well. ADME properties and toxicity profiles were evaluated using online web servers. Molecular dynamics simulations explored interactions of DMTPC and DMTPD with the leukemia inhibitory factor protein (PDB ID: 1EMR) compared to Nilotinib. Molecular docking studies indicated DMTPC′s promising potential with a binding energy of −8.8 kcal/mol, approaching Nilotinib's −9.4 kcal/mol. This investigation accentuates the burgeoning research paradigm of exploiting azo compounds in the formidable battle against leukemia, opening new avenues for breakthroughs in this field.

Experimental Study on Ultrasonic Cavitation Intensity Based on Fluorescence Analysis

The Ultrasonic cavitation effect has been widely used in mechanical engineering, chemical engineering, biomedicine, and many other fields. The quantitative characterization of ultrasonic cavitation intensity has always been a difficulty. Based on this, a fluorescence analysis method has been adopted to explore ultrasonic cavitation intensity in this paper. In the experiment of fluorescence intensity measurement, terephthalic acid (TA) was used as the fluorescent probe, ultrasonic power, ultrasonic frequency, and irradiation time were independent variables, and fluorescence intensity and fluorescence peak area were used as experimental results. The collapse of cavitation bubble will cause molecular bond breakage and release ·OH, and the non-fluorescent substance TA will form the strong fluorescent substance TAOH with ·OH. The spectra of the treated samples were measured by a F-7000 fluorescence spectrophotometer. The results showed that the fluorescence intensity and fluorescence peak area increased rapidly after ultrasonic cavitation treatment, and then increased slowly with the increase of ultrasonic power, which gradually increased with the increase of irradiation time. They first decreased and then increased with the increase of ultrasonic frequency from 20 kHz to 40 kHz. The irradiation time was the most influential factor, and the cavitation intensity of low frequency was higher overall. The fluorescence intensity and fluorescence peak area of the samples increased by 2–20 times after ultrasonic treatment, which could increase from 69 and 5238 to 1387 and 95451, respectively. After the irradiation time exceeded 25 min, the growth rate of fluorescence intensity slowed down, which was caused by the decrease of gas content and TA concentration in the solution. The study quantitatively characterized the cavitation intensity, reflecting the advantages of fluorescence analysis, and provided a basis for the further study of ultrasonic cavitation.

Gut microbiota contribution to selenium deficiency-induced gut-liver inflammation.

There is limited knowledge about the factors that drive gut-liver axis changes after selenium (Se) deficiency-induced gut or liver injuries. Thus, we tested Se deficiency in mice to determine its effects on intestinal bacterial balance and whether it induced liver injury. Serum Se concentration, lipopolysaccharide (LPS) level, and liver injury biomarkers were tested using a biochemical method, while pathological changes in the liver and jejunum were observed via hematoxylin and eosin stain, and a fluorescence spectrophotometer was used to evaluate intestinal permeability. Tight junction (TJ)-related and toll-like receptor (TLR) signaling-related pathway genes and proteins were tested using quantitative polymerase chain reaction, western blotting, immunohistochemistry, and 16S ribosomal ribonucleic acid gene-targeted sequencing of jejunum microorganisms. Se deficiency significantly decreased glutathione peroxidase activity and disrupted the intestinal flora, with the most significant effect being a decrease in Lactobacillus reuteri. The expression of TJ-related genes and proteins decreased significantly with increased treatment time, whereas supplementation with Se, fecal microbiota transplantation, or L. reuteri reversed these decreases. Signs of liver injury and LPS content were significantly increased after intestinal flora imbalance or jejunum injury, and the levels of TLR signaling-related genes were significantly increased. The results indicated that Se deficiency disrupted the microbiota balance, decreased the expression of intestinal TJ factors, and increased intestinal permeability. By contrast, LPS increased due to a bacterial imbalance, which may induce inflammatory liver injury via the TLR4 signaling pathway.

Development of a Novel Sulfur Quantum Dots: Synthesis, 99mTc Radiolabeling, and Biodistribution.

Sulfur quantum dots (SQDs) as free heavy metal element quantum dots have promising applications in diagnosis and therapy; however, SQDs' in vivo biodistribution has not been studied. In the current study, SQDs were synthesized directly from cheap sublimated sulfur powder via a one-pot solvothermal method, and sucrose was used as a stabilizer to enhance stability and biocompatibility. The as-obtained SQDs with an average size of 4.6 nm exhibited great water dispersity, highly favorable quantum yield (21.5%), and uniformly spherical shape which were confirmed by UV-Vis, fluorescence spectrophotometer, TEM, and FESEM/EDX/PSA analyses. Moreover, the as-synthesized SQDs had very low cytotoxicity based on cancer (C26) and normal (L929) cell lines via MTT assay. And also, SQDs were radio-labeled directly by Technetium-99m (99mTc), which had good stability ranging from 86 to 99% in PBS and human serum. The SQDs' cell uptake on C26 and L929 cell lines demonstrated that cancer cells had more uptake than normal cells by increasing concentrations. Moreover, SQDs' in vivo biodistribution results displayed high kidney dose accumulation and rapid renal clearance, making them suitable for imaging and therapeutic applications.

A Chitosan-Based Fluorescent Probe Combined with Smartphone Technology for the Detection of Hypochlorite in Pure Water.

Using chitosan as a raw material, 1,8-naphthimide as the fluorescent chromophore, and sulfur-containing compounds as the recognition groups, a novel naphthimide-functionalized chitosan probe, CS-BNS, for the detection of ClO- was successfully synthesized. The modification of chitosan was verified by SEM, XRD, FTIR, mapping, 13C-NMR, TG and the structure of the probe molecule was characterized. The identification performance of the probes was studied using UV and fluorescence spectrophotometers. The results show that CS-BNS exhibits a specific response to ClO- based on the oxidative reaction of ClO- to the recognition motifs, as well as a good resistance to interference. And the probe has high sensitivity and fast response time, and can complete the detection of ClO- in a pure water system within 60 s. The probe can also quantify ClO- (y = 30.698x + 532.37, R2 = 0.9833) with a detection limit as low as 0.27 μM. In addition, the combination of the probe with smartphone technology enables the visualization and real-time monitoring of ClO-. Moreover, an identification system for ClO- was established by combining the probe with smartphone technology, which realized the visualization and real-time monitoring of ClO-.

Fabrication of biosensor for the assessment of radon and lead levels in the blood

This study aimed to develop and test a biosensor for detecting radioactive radon gas and lead ions in blood samples collected from donors in Iraq. The biosensor was made up of aptamer, acetic acid, malachite green, and TRIS-HAC, and results were measured using a fluorescence spectrophotometer. This study found that 222Rn in the blood varied between individuals, with higher levels in males and smokers, and the highest concentration found in a male patient with cancer. The biosensor used to detect 222Rn in the blood was effective, sensitive, and low-cost, and the levels detected were within the limits set by the WHO. The study also looked at pb+2, a toxic metal, and found that levels were within permissible limits. The biosensor was also effective in detecting pb+2. The correlations between the variables are generally weak to moderate, and there are some negative relationships between humidity and other variables. There are also some strong positive relationships between temperature (Tin) and temperature (Tout). The results suggest that these variables are not strongly correlated with each other, which is an important finding for understanding their potential effects on health outcomes. However, further validation and testing may be necessary before its widespread use in clinical settings. This study highlights the importance of monitoring these substances in the blood, especially for individuals with occupational exposure to radiation. The biosensor was found to be sensitive, cost-effective, fast to manufacture, and efficient compared to other detection devices. Therefore, the study recommends the use of this biosensor for measuring radon and lead ions in blood samples. The biosensor used in this study could be a useful tool for such monitoring.

Discovery and experimental verification of the spectral characteristics at different growth stages of Aurelia

Under the dual pressure of human activities and global changes, jellyfish outbreaks have occurred frequently in China's offshore waters in recent years, with serious impacts on marine fisheries, coastal tourism, marine ecology and cooling water systems for coastal industries. In order to accurately identify the origin of Aurelia and to be more proactive in the prevention and control of Aurelia outbreaks, this article proposed the use of ultraviolet (UV) and fluorescence spectroscopy to detect the polyps, ephyrae and larvae of Aurelia at different growth stages. The AvaSpec-2048 UV visible fibre spectrometer and the F-7000 fluorescence spectrophotometer were used to focus on studying the UV absorption spectrum and three-dimensional fluorescence spectrum of the polyps, ephyrae, and larvae of Aurelia cultured under laboratory conditions. The research results showed that the three-dimensional fluorescence spectrum of the three different growth stages of Aurelia, namely polyps, ephyrae and larvae of Aurelia, had relatively similar fluorescence distributions, and the fluorescence intensity was different from each other. However, the absorption peaks of the three UV absorption spectrum appeared in different UV light bands and there were absorption peaks of different intensities. The different spectral characteristics at different growth stages of Aurelia provide new ideas and methods for exploring the birthplace of Aurelia.

Toxicity of Diphenyltin Chloride on viable count of aerobic bacteria from River Benue.

This research was carried out to determine the toxicity of diphenyltin chloride on viable count of freshwater aerobic bacteria. Water samples obtained from a depth of 15 cm at five sampling points along river Benue were spiked with 3 mM of DPTCl to have a duplicate setup of three (3) treatments. Organotin degradation was determined by measuring the decrease in the concentration of DPTCl using an X-ray fluorescence spectrophotometer on days 0, 14, 28, 42, and 56 and the viable count of bacteria was also determined using spread plate technique on MSA. DPTCl concentration was further varied (5 mM, 7 mM and 10 mM) to test levels of toxicity to viable count of bacteria as well as bacterial resistance. patio sequencing technique was used to determine the metagenomics of bacteria species capable of DPTCl degradation from the water samples. Percentage of chemically degraded (40.29%) during the initial two weeks of experiment when the bacterial population was high, was more than the percentage degraded (11.49%) during the last two weeks of the experiment when the biocidal effect of DPTCl had drastically reduced the bacterial population. Of the initial bacterial viable count of 47.2 x 102 that survived the 56 days degradation exercise, only 1.8x101 (0.38%) grew on 7 mM concentration of DPTCl, and none on 10 mM DPTCl. The impact of DPTCl on the viable count of bacteria was statistically significant. Stenotrophomonas spp (29.6%) was the dominant bacterium in DPT degradation, others include; Comamonas spp (9.31%), Microbacterium spp (8.41%) Pseudomonas viridiflava (4.18%), and Stenotrophomonas geniculata (3.46%). Organotins. Diphenyltin though a di-alkyl organotin, is equally a toxic and persistent pollutant that cannot be easily degraded without the use of nutrient amendment. The toxic effect of DPT as demonstrated in this study shows that TPT and other tri-alkyl organotin should not be considered detoxified especially against microorganisms simply because they have been de-alkylated.Sites contaminated by organotins should not be considered remediated until all di and mono alkyl derivatives are completely degraded. Since our natural environments usually have no sufficient nutrient amendments for elimination of pollutants, there is need to engage abiotic processes that can assist the activities of microorganisms in order to speed up remediation process.

Impact of the Drug Loading Method on the Drug Distribution and Biological Efficacy of Exosomes.

Exosomes are biological nanovesicles that are intrinsically loaded with thousands of biomacromolecules and are principally responsible for cell-to-cell communication. Inspired by the natural payload, they have been extensively investigated as drug delivery vehicles; however, the drug distribution, whether into or onto exosomes, is still debatable. In the present work, we have tried to investigate it systemically by selecting 5-fluorouracil (5-FU) (hydrophilic) and paclitaxel (PAC) (hydrophobic), drugs with very different physicochemical characteristics, for the loading to the exosomes. Exosomes were obtained from bovine milk, and the drugs were loaded using three different methods: incubation, sonication, and triton x-100. The particle size was found to be approximately 100 nm in all the cases; however, the highest drug loading was found in the sonication method. Fluorescence spectrophotometer, EDX analysis, EDX mapping, XPS, and XRD analysis indicated the possible presence of more drugs over the surface in the case of the incubation method. Drugs loaded by the sonication method had more controlled release than simple incubation and triton x-100. The method of drug loading had an insignificant effect on the cytotoxicity while in line with our previous observation, the combination (PAC and 5-FU) exhibited synergism as evidenced by ROS assay, colony formation assay, and mitochondrial membrane potential assay.

Effects of Heat Treatment on the Structural and Functional Properties of Phaseolus vulgaris L. Protein.

The paper presents the effect of heat treatment at 80 °C at different times (3, 5, 7, and 9 min) on the structural and functional properties of Phaseolus vulgaris L. protein (PVP, bean protein powder). Surface and structure properties of PVP after heat treatment were analyzed using a Fourier transform infrared spectrometer (FTIR), a fluorescence spectrophotometer, a visible light spectrophotometer, a laser particle size analyzer, and other equipment. The secondary structure and surface hydrophobicity (H0) of PVP changed significantly after heat treatment: the β-sheet content decreased from 25.32 ± 0.09% to 24.66 ± 0.09%, the random coil content increased from 23.91 ± 0.11% to 25.68 ± 0.08%, and the H0 rose by 28.96-64.99%. In addition, the functional properties of PVP after heat treatment were analyzed. After heat treatment, the emulsifying activity index (EAI) of PVP increased from 78.52 ± 2.01 m2/g to 98.21 ± 1.33 m2/g, the foaming ability (FA) improved from 87.31 ± 2.56% to 95.82 ± 2.96%, and the foam stability (FS) rose from 53.23 ± 1.72% to 58.71 ± 2.18%. Finally, the degree of hydrolysis (DH) of PVP after gastrointestinal simulated digestion in vitro was detected by the Ortho-Phthal (OPA) method. Heat treatment enhanced the DH of PVP from 62.34 ± 0.31% to 73.64 ± 0.53%. It was confirmed that heat treatment changed the structural properties of PVP and improved its foamability, emulsification, and digestibility. It provides ideas for improving PVP's potential and producing new foods with rich nutrition, multiple functions, and easy absorption.

Photocatalytic activity of TiO2-ZnO/g-C3N4 nanocomposites for methylene orange and Rhodamine B dyes removal from water and photocatalytic hydrogen generation

In this work, for the removal of azo dyes that cause environmental pollution, TiO2-ZnO has been modified with graphitic carbon nitride (g-C3N4) to form an advanced hetero-linked photocatalyst. With this catalyst, photocatalytic hydrogen production and photodegradation activity against methylene orange (MO) and rhodamineB (RhB) dye removal were studied. The synthesized nanostructure was extensively characterized by several techniques such as XRD, TEM, UV–Vis and fluorescence spectrophotometer (PL) techniques. According to the analysis, a significant increase in the photocatalytic efficiency of TiO2-ZnO was determined after it was modified with g-C3N4 nanostructures. The combination between TiO2-ZnO and g-C3N4 was shown to be responsible for the improvement in photocatalytic activity because it significantly decreased electron-hole recombination. After 90 min the 62.81% of MO dye was removed but at 120 min only 57% of RhB was degraded. In addition, the antibacterial activity of TiO2-ZnO/g-C3N4 catalyst was carried out against gram positive and gram negatif bacteria. The bacterial inhibition (%) of TiO2-ZnO/g-C3N4 catalyst.was found to be 44 % against E. coli and 33 % against at 100 μg/ml concentration. In line with the analyzes obtained with this study, important results have been revealed for the application of photocatalytic methods in more industrial dimensions in the production of hydrogen, which is a valuable energy type.

Effects of different pH, temperature, and pressurisation time on the stability of chlorophylls treated with Zn2+ and high hydrostatic pressure

SummaryThis study provides an effective method to improve the stability of chlorophylls. The effects of different pH, temperature, and pressurisation time on the colour, antioxidant activity, Zn2+ replacement ratio, structure, and thermal stability of chlorophylls treated with Zn2+ (10 mg 100 mL−1) and high hydrostatic pressure (500 MPa) were investigated. The electronic eye, ultraviolet spectrophotometer, high‐performance liquid chromatography, Fourier transform infrared, and high hydrostatic pressure (HHP) online monitor cooperated with fluorescence spectrophotometer were used to investigate the effects of different pH values, water bath temperatures, and pressurisation time on the colour, antioxidant activity, Zn2+ replacement ratio, and structure of chlorophylls. The highest −a* (6.92), antioxidant activity (ABTS 41.01 g ACE 100 g−1, DPPH 52.86 g ACE 100 g−1, FRAP 35.72 g TE 100 g−1 DW), and Zn2+ replacement ratio (47.32%) were obtained at 50 °C, pH = 7.0, and 20 min. It is hoped that this study will provide a new idea for the protection of natural pigments.

Optimized silk fibroin nanoparticle functionalization with anti-CEA nanobody enhancing active targeting of colorectal cancer cells

This work aimed to establish a simple and feasible method to obtain silk fibroin nanoparticles (SFNPs) with uniform particles size, and then modify the SFNPs with nanobody (Nb) 11C12 targeting the proximal membrane end of carcinoembryonic antigen on the surface of colorectal cancer (CRC) cells. The regenerated silk fibroin (SF) was isolated using ultrafiltration tubes with a 50 kDa molecular weight cut-off, and the retention fraction (named as SF > 50 kDa) was further self-assembled into SFNPs by ethanol induction. Scanning electron microscope (SEM) and high-resolution transmission electron microscop showed that the SFNPs with uniform particles size were formed. Due to electrostatic adsorption and pH responsiveness, SFNPs have been proved to effectively load and release the anticancer drug doxorubicin hydrochloride (DOX) (DOX@SFNPs). Further, targeting molecule Nb 11C12 was used to modify these nanoparticles, constituting the targeted outer layer of the drug delivery system (DOX@SFNPs-11C12), achieving precise localization to cancer cells. The release amount of DOX observed from in vitro drug release profiles increased as follows: pH 7.4 < pH 6.8 < pH 5.4, demonstrating that the DOX release could be accelerated in a weakly acidic environment. In vitro cytotoxicity experiments displayed that SFNPs-11C12 nanoparticles exhibited good safety and biocompatibility. Drug-loaded nanoparticles, DOX@SFNPs-11C12, led to higher LoVo cells apoptosis compared to DOX@SFNPs. Fluorescence spectrophotometer characterization and confocal laser scanning microscopy further showed that the internalization of DOX was highest in the DOX@SFNPs-11C12, certifying that the introduced targeting molecule enhanced the uptake of drug delivery system by LoVo cells. This study provides a simple and operational approach to developing an optimized SFNPs drug delivery system modified by targeting Nb, which can be a good candidate for CRC therapy.

Preparation of pH/Light dual-responsive biocompatible polymer micelles: Application to curcumin delivery

Polymer micelles play an important role in the research of drug delivery system because of their nano-size, unique “core-shell” structure and surface modifiability. A pH/photosensitive drug carrier, PEG-PDMAEMA-PNBAE, was synthesized by atom transfer radical polymerization (ATRP) using hydrophilic poly (N, N dimethylaminoethyl methacrylate) (PDMAEMA) as the pH-responsive chain segment and hydrophobic poly (o-nitrobenzyl acrylate) (PNBAE) as the light-responsive chain segment. The molecular and structural characteristics of the polymer were spectroscopically characterized with Fourier transform infrared spectrometer (FT-IR), Nuclear magnetic resonance hydrogen spectrum (1H NMR) and Gel permeation chromatography column (GPC). The morphology and size of micelles were observed by Scanning electron microscope (SEM) and Transmission electron microscope (TEM). The stability of micelles was detected by Laser particle size analyzer (DLS). The Critical micelle concentration (CMC) of the polymer was analyzed by Fluorescence spectrophotometer (Flu), and the photosensitivity of the micelles was determined by Ultraviolet–visible spectrophotometer (UV). The results showed that the synthesized polymers could self-assemble into homogeneous and stable spherical micelles and their particle size was about 100 nm with effective light sensitivity. Curcumin (Cur) was used as a model drug to investigate the adsorption and release abilities of the micelles. The adsorption performance test of the polymeric micelles showed an encapsulation rate of 77.82% and a drug loading capacity of 13.46%. In vitro drug release results showed cumulative drug release rates of 31.79% and 46.55% at pH 5.5 and pH 5.5+UV, indicating the dual pH and light responsiveness of the synthesized carrier. The in vitro hemolysis and cytotoxicity test demonstrated that the carrier has good biosafety.

#6600 ASSOCIATION BETWEEN ADVANCED GLYCATION END-PRODUCTS AND SARCOPENIA IN PATIENTS WITH CHRONIC KIDNEY DISEASE

Abstract Background and Aims In patients with chronic kidney disease (CKD), there is an overproduction and accumulation of advanced glycation end-products (AGEs). Since AGEs may have detrimental effects on muscular trophism and performance, we evaluated whether they may contribute to the onset of sarcopenia in CKD patients. Method We enrolled 117 patients. The AGEs were quantified by fluorescence intensity using a fluorescence spectrophotometer and soluble receptor for AGE (sRAGE) isoforms by ELISA. As for the sarcopenia definition, we used the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria. Results The average age was 80 ± 11 years, 70% were males, and the mean eGFR was 25 + 11 mL/min/1.73 m2. Sarcopenia was diagnosed in 26 patients (with a prevalence of 22%). The sarcopenic patients had higher levels of circulating AGEs (3405 ± 951 vs. 2912 ± 722 A.U., p = 0.005). AGEs were higher in subjects with a lower midarm muscle circumference (MAMC) (3322 ± 919 vs. 2883 ± 700 A.U., respectively; p = 0.005) and were directly correlated with the gait test time (r = 0.180, p = 0.049). The total sRAGE and its different isoforms (esRAGE and cRAGE) did not differ in patients with or without sarcopenia. Conclusion In older CKD patients, AGEs, but not sRAGE, are associated with the presence of sarcopenia. Therefore, AGEs may contribute to the complex pathophysiology leading to the development of sarcopenia in CKD patients.