Exploring Qualitative and Quantitative Decoration on Amine-Modified Mesoporous Silica for Enhance Adsorption Performances

Using the triblock copolymer Pluronic F127 as a surfactant, tetraethyl orthosilicate (TEOS) as a silica source, and hydroxylamine hydrochloride as an amine source, a group of amines-modified mesoporous silica Santa Barbara Amorph-16 (SBA-16) materials with different template withdrawal methods and amine loading concentrations were prepared through sol-gel conditions. The investigation will provide qualitative and quantitative information on amine-modified SBA-16 decoration with a brief overview of the non-destructive analysis methods for advanced materials as adsorbent candidates. Highly ordered mesostructured amine-modified SBA-16 materials were prepared using high-temperature (or calcination) and solvent extraction de-templating methods. Mesostructured amine-modified SBA-16 has been successfully examined using a Synchrotron Radiation Low-Angle X-ray Diffraction (SR-LXRD) instrument for phase identification, Small-Angle Synchrotron X-rays Scattering (SAXS) for identifying structural changes in a porous material, Fourier Transform Infrared (FTIR) for identifying functional groups, Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) elemental analyzer for determining the number of silica, oxygen, and nitrogen elements, and a Specific Surface Area (SSA) analyzer for measuring the specific surface areas. The SR-LXRD and SAXS results demonstrated that the synthesized novel materials were defined unambiguously as a bi-continuous cubic body center Im3m mesostructured. FTIR and SEM-EDS analyses verified that the amine groups were uniformly deposited on the SBA-16 surface. The SSA analyzer results also clarified that the novel materials exhibited ordered and meso-framework amine-modified SBA-16 with a large surface area. Novel materials can be considered high-potential uranium adsorbent candidates. Preliminary adsorption investigations have shown that the amine-modified SBA-16 materials can adsorb uranium in natural seawater showing an uptake capacity of as much as 24.48 mg-U/g-adsorbent

Photosensitizer effects on cancerous cells: A combined study using synchrotron infrared and fluorescence microscopies

International audienceHypocrellin A (HA), a lipid-soluble peryloquinone derivative, isolated from natural fungus sacs of Hypocrella bambusae, has been reported to be a highly potential photosensitizer in photodynamic therapy (PDT). It has been studied increasingly because of its anticancer activities when irradiated with light. We have studied the interaction mechanisms of HA with HeLa cells as a function of incubation time. Fluorescence microscopy confirmed that HA localisation is limited in the cytoplasm before eventually concentrating in clusters around the nucleus. The IR spectra of HA-treated, PDT-treated and control HeLa cells were recorded at the ESRF Infrared beamline (ID21). Principal component analysis has been used to assess the IR spectral changes between the various HeLa cells spectral data sets (The Unscrambler software, CAMO). PCA revealed that there is a frequency shift of protein amide I and amide II vibrational bands, indicating changes in the protein secondary structures of the HA-treated and PDT-treated cancer cells compared to the control cells. In addition, the relative DNA intensity in HA-treated cells decreases gradually along the incubation time. The use of synchrotron infrared microscopy is shown to be of paramount importance for targeting specifically the biochemical modification induced in the cell nucleus

Analysis of xanthyletin and secondary metabolites from Pseudomonas stutzeri ST1302 and Klebsiella pneumoniae ST2501 against Pythium insidiosum

Abstract Background Pythium insidiosum is a member of the oomycetes class of aquatic fungus-like microorganisms. It can infect humans and animals through skin wounds and the eyes, causing pythiosis, an infectious disease with high morbidity and mortality rates. Antifungal agents are ineffective as pythiosis treatments because ergosterol, the target site of most antifungal agents, is not found in the P. insidiosum cytoplasmic membrane. The best choice for treatment is surgical removal of the infected organ. While natural plant products or secretory substances from bacterial flora have exhibited in vitro anti-P. insidiosum activity, their mechanism of action remains unknown. Therefore, this study hypothesized that the mechanism of action could be related to changes in P. insidiosum biochemical composition (such as lipid, carbohydrate, protein or nucleic acid) following exposure to the inhibitory substances. The biochemical composition of P. insidiosum was investigated by Synchrotron radiation-based Fourier-transform infrared (FTIR) microspectroscopy. Results Fraction No.6 from the crude extract of P. stutzeri ST1302, fraction No.1 from the crude extract of K. pneumoniae ST2501 and xanthyletin were used as anti-P. insidiosum substances, with MFCs at 3.125, 1.57–1.91, 0.003 mg/ml, respectively. The synchrotron FTIR results show that the deconvoluted peak distributions in the amide I, amide II, and mixed regions were significantly different between the treatment and control groups. Conclusions Xanthyletin and the secondary metabolites from P. stutzeri ST1302 and K. pneumoniae ST2501 exerted anti-P. insidiosum activity that clearly changed the proteins in P. insidiosum. Further study, including proteomics analysis and in vivo susceptibility testing, should be undertaken to develop a better understanding of the mechanism of anti-P. insidiosum activity

Toxicity and phototoxicity of Hypocrellin A on malignant human cell lines, evidence of a synergistic action of photodynamic therapy with Imatinib mesylate

International audiencePhotodynamic therapy combines a photosensitizer, localised preferentially in malignant cells with light activation. Hypocrellin A (HA), a lipid-soluble peryloquinone, is considered as a high potential photosensitizer.We report dose and light irradiation effects of HA on HeLa, Calu and K562 cell lines, the latter including a subclone resistant to Imatinib mesylate (IM, Gleevec). All cell lines and subclones tested are sensitive to HA PDT.In the epithelial tumour cell lines, we observe a significant photosensitizing effect in the presence of HA. In the leukemic K562 cells, HA exposure led to an inhibitory effect, which was not seen in the K562 cells resistant to Imatinib mesylate. However, experiments using IM and HA led to a reversal of IM-resistant phenotype in this cell line, with evidence of a major sensitizing effect of photodynamic therapy.Overall our results suggest a phototoxicity of HA in epithelial cell lines and demonstrate for the first time, a synergy between IM and photodynamic therapy to circumvent IM-resistance

Characteristic Evaluation of Gel Formulation Containing Niosomes of Melatonin or Its Derivative and Mucoadhesive Properties Using ATR-FTIR Spectroscopy

Chitosan or polyvinyl pyrrolidone (PVP) were used in combination with hydroxypropyl methylcellulose (HPMC) and poloxamer 407 (P407) as gelling agents for oral drug delivery. The performance interaction with mucin of chitosan-composed gel (F1) and PVP-composed gel (F2) was compared using attenuated total reflectance–Fourier-transform infrared (ATR-FTIR) spectroscopy at controlled temperatures of 25 and 37 °C for 1 and 5 min. F1 containing niosome-entrapped melatonin or its derivatives was investigated for mucoadhesive interaction on mucosa by ATR-FTIR spectroscopy under the same conditions. The results showed that F1-treated mucin gave a significantly lower amide I/amide II ratio than untreated mucin and F2-treated mucin did within 1 min, suggesting improved rapid affinity between mucin and chitosan. The spectra of mucosa treated with F1 incorporating niosomes of melatonin or its derivatives showed peak shifts at C=O (amide I), N-H (amide II), and carbohydrate regions and an associated decrease in the amide I/amide II ratio and increase in the carbohydrate/amide II ratio. These results indicated electrostatic interaction and hydrogen bonding between chitosan and mucin on the mucosa. In conclusion, the molecular interaction between gels and mucin/mucosa detected at amide I and amide II of proteins and the carbohydrate region could lead to an improved mucoadhesive property of the gel on the mucosa