Singlet Oxygen Chemistry in Water: A Porous Vycor GlassSupported Photosensitizer

Singlet molecular oxygen [1O2 (1Δg)] is generated cleanly in aqueous solution upon irradiation of a heterogeneous complex, meso-tetra(N-methyl-4-pyridyl)porphine (1) adsorbed onto porous Vycor glass (PVG). The cationic photosensitizer 1 tightly binds onto PVG and gives a stable material, which does not dissociate 1 into the surrounding aqueous phase. The production of 1O2 was measured by monitoring the time-resolved 1O2 (1Δg) phosphorescence at 1270 nm. Indirect analysis of 1O2 generation was also carried out with the photooxidation oftrans-2-methyl-2-pentenoate anion, which afforded the corresponding hydroperoxide. Sensitizer-1-impregnated PVG gives rise to a new singlet oxygen generator but more importantly provides a heterogeneous system for use in water

Photosensitizer Drug Delivery via an Optical Fiber

: An optical fiber has been developed with a maneuverable miniprobe tip that sparges O2 gas and photodetaches pheophorbide (sensitizer) molecules. Singlet oxygen is produced at the probe tip surface which reacts with an alkene spacer group releasing sensitizer upon fragmentation of a dioxetane intermediate. Optimal sensitizer photorelease occurred when the probe tip was loaded with 60 nmol sensitizer, where crowding of the pheophorbide molecules and self-quenching were kept to a minimum. The fiber optic tip delivered pheophorbide molecules and singlet oxygen to discrete locations. The 60 nmol sensitizer was delivered into petrolatum; however, sensitizer release was less efficient in toluene-d8 (3.6 nmol) where most had remained adsorbed on the probe tip, even after the covalent alkene spacer bond had been broken. The results open the door to a new area of fiber optic-guided sensitizer delivery for the potential photodynamic therapy of hypoxic structures requiring cytotoxic control

Chitosan, alginate, and carboxymethyl cellulose-based film for a controlled release of indocyanine green for antibiofilm applications

Biofilms on medical devices and wounds significantly contribute to chronic infections in healthcare, as they are highly resistant and difficult to remove, endangering human life and health. Searching for a suitable system to counteract this issue, here we enriched a chitosan (CS), sodium alginate (SA), and carboxymethylcellulose (CMC) film with the indocyanine green (ICG) dye as an antibiofilm drug delivery system. These films retained their structural integrity, showing a homogenous dye distribution. Modulating the ICG concentration enabled obtaining different aggregates, whose stability and release kinetics were evaluated in a phosphate-buffered saline (PBS) solution. A portion of ICG remains trapped in the polymer matrix as a local reservoir, and its release was concentration-dependent, with lower or higher concentrations promoting the monomeric ICG or the preferred J-type aggregate. Infrared spectroscopy elucidated non-covalent interactions between the dye and polysaccharide matrix. X-ray diffraction revealed that low and high ICG concentrations improved film crystallinity, while an intermediate concentration preserved the amorphous structure. The dye enhanced film stability by reducing solubility and moisture uptake. We also modeled the ICG release, which followed Higuchi’s diffusion-controlled model, with increasing concentrations enhancing aggregate diffusion. Lastly, ICG-enriched films effectively inhibited Staphylococcus aureus biofilm formation, demonstrating their potential as antimicrobial coatings

P010 Measurement of colonic mucosal content of biologics with the use of magnetic resonance imaging (MRI): A pilot study in patients with ulcerative colitis

Abstract Background Anti-tumour necrosis factor antagonists (infliximab) as well as other molecules with different modes of action, including anti-integrin agents (vedolizumab), are currently used in patients with ulcerative colitis (UC Numerous studies have demonstrated a positive correlation between serum biologic drug concentrations and favourable therapeutic outcomes, whereas low or undetectable drug concentrations can lead to treatment failure. However, despite immunological issues, lack of and or loss of response may also be attributed to drug pharmacokinetics, of which penetration to the target tissue (colon wall) may play a crucial role Methods We used MRI to perform biochemical analyses of infliximab, adalimumab and vedolizumab concentrations testing the hypothesis that MRI relaxation time can be used to track antibodies in both mucosal biopsy samples and serum. All MR scans were performed with an Optima MR360 from General Electric Healthcare. To determine spin–lattice (T1) and spin–spin (T2) relaxation times, the Fast Spin Echo (FSE) sequence was used. Results The measured values of T1 relaxation times for infliximab, adalimumab, and vedolizumab were 2227 ± 35 ms, 2000 ± 22 ms and 1288 ± 15 ms, respectively. The obtained T2 relaxation times were 130 ± 11 ms, 90 ± 5, and 75 ± 10 ms, respectively. A decrease of both T1 and T2 values of 15 ± 3% are observed in serum from patients with ulcerative colitis. The values of infliximab and adalimumab were similar; the values of vedolizumab measurements in serum were about 50% lower. We find primary evidence that in T1 and T2 decreased in serum samples with ulcerative colitis and increase with the administration of infliximab, adalimumab and vedolizumab drugs. Samples of healthy tissue have T1 and T2 in the range of 2700 ± 5 ms and 150 ms ± 5 ms, respectively. A 30% decrease in T1 and T2 are observed for samples with ulcerative colitis. In this pilot study, we observed that values of T1 and T2 for tissues and serum that contain infliximab and adalimumab are similar, but vedolizumab shows a difference of about 30% when compared with infliximab and adalimumab. Conclusion MRI is an excellent method for quantitative and qualitative measurements of drug content in tissues and biological fluids. This is an innovative use of magnetic resonance imaging to develop a methodology for imaging of drugs that act as contrast agents via interaction with water in serum and tissue. </jats:sec

Exhaled nitric oxide in smokers and former smokers with chronic obstructive pulmonary disease

Background: Measurement of fractional exhaled nitric oxide (FeNO) is a useful technique for detection of eosinophilic airway inflammation and assessment of efficiency of corticosteroid treatment in patents with respiratory disease. Generally studies agree that measurement of FeNO is a useful non-invasive biomarker in patients with chronic obstructive pulmonary disease (COPD), however, there are reports that do not confirm such a relationship between FeNO and COPD. Aim of the study: The main objective of this study was to investigate FeNO levels in Polish patients with COPD compared to healthy controls. As a secondary objective, we assessed the influence of smoking on FeNO levels in healthy patients, and patients with COPD. Material and methods: FeNO concentration was measured using an electrochemical analyzer in healthy nonsmokers (n=21), healthy smokers (n=25), and former smokers with COPD (n=30) and smokers with COPD (n=38). General characteristics, hematological variables and serum biochemical parameters were also obtained and analyzed using the Kruskal-Wallis test. Results: FeNO measurement revealed significantly reduced NO levels in healthy smokers compared to healthy non-smokers, former smokers with COPD and smokers with COPD (median [range]: 14 [6–17] vs. 21 [15–29], 25 [15–53], and 19 [11–32] ppb, respectively, p<0.001). Moreover, we found increased FeNO levels in ex-smokers with COPD compared with smokers with COPD (p<0.05). No associations between FeNO and other analyzed parameters were found. Conclusions: Levels of FeNO, measured by with an electrochemical analyzer, were elevated among patients with COPD compared to healthy non-smoking controls. Moreover, our study confirms that smoking results in a reduction in FeNO concentration in both healthy patients and patients with COPD

Singlet Oxygen Generation on Porous Superhydrophobic Surfaces: Effect of Gas Flow and Sensitizer Wetting on Trapping Efficiency

We describe physical-organic studies of singlet oxygen generation and transport into an aqueous solution supported on superhydrophobic surfaces on which silicon–phthalocyanine (Pc) particles are immobilized. Singlet oxygen (¹O₂) was trapped by a water-soluble anthracene compound and monitored <i>in situ</i> using a UV–vis spectrometer. When oxygen flows through the porous superhydrophobic surface, singlet oxygen generated in the plastron (i.e., the gas layer beneath the liquid) is transported into the solution within gas bubbles, thereby increasing the liquid–gas surface area over which singlet oxygen can be trapped. Higher photooxidation rates were achieved in flowing oxygen, as compared to when the gas in the plastron was static. Superhydrophobic surfaces were also synthesized so that the Pc particles were located in contact with, or isolated from, the aqueous solution to evaluate the relative effectiveness of singlet oxygen generated in solution and the gas phase, respectively; singlet oxygen generated on particles wetted by the solution was trapped more efficiently than singlet oxygen generated in the plastron, even in the presence of flowing oxygen gas. A mechanism is proposed that explains how Pc particle wetting, plastron gas composition and flow rate as well as gas saturation of the aqueous solution affect singlet oxygen trapping efficiency. These stable superhydrophobic surfaces, which can physically isolate the photosensitizer particles from the solution may be of practical importance for delivering singlet oxygen for water purification and medical devices