J. Mater. Chem. B

Biocompatible, non- ionic oil-in-water (O/W) microemulsion was developed to encapsulate and deliver novel lipophilic polymers possessing photoacoustic properties. , In the present study a biocompatible oil-in-water (O/W) microemulsion was developed carrying short-wave infrared (SWIR) π-conjugated polymers and possessing photoacoustic properties for the first time. SWIR and NIR absorbing conjugated polymers were accomplished to be dissolved in a Food & Drug Administration (FDA) approved natural oil limonene, to formulate an O/W microemulsion using biocompatible surfactants (Span80, Labrasol®). Detailed structural characterization in the absence and presence of the polymers was performed by means of dynamic light scattering (DLS), small-angle X-ray scattering (SAXS) and electron paramagnetic resonance (EPR) spectroscopy. In terms of biological evaluation of the loaded microemulsions, inhibition of cell proliferation in various cancer cell lines without exhibiting significant cytotoxicity was tested through the MTT assay. The developed π-conjugated polymers hosted in O/W microemulsions represent a technological approach with a wide range of biomedical and bioelectronic applications and in this contribution, their photoacoustic properties are presented as a proof-of-concept

Thyroid hormone alterations in critically and non-critically ill patients with SARS-CoV-2 infection

Objective: Following the evolution of COVID-19 pandemic, reports pointed on a high prevalence of thyroiditis-related thyrotoxicosis. Interpretation of thyroid tests during illness, however, is hampered by changes occurring in the context of non-thyroidal illness syndrome (NTIS). In order to elucidate these findings, w e studied thyroid function in carefully selected cohorts of COVID-19 positive and negative patients. Design: Cohort observational study. Methods: We measured TSH, FT4, T3 within 24 h of admission in 196 patients without thyroid disease and/or confounding medications. In this study, 102 patients were SARS-CoV-2 positive; 41 admitted in the ICU, 46 in the ward and 15 outpatients. Controls consisted of 94 SARS-CoV-2 negative patients; 39 in the ICU and 55 in the ward. We designated the thyroid hormone patterns as consistent with NTIS, thyrotoxicosis and hypothyroidism. Results: A NTIS pattern was encountered in 60% of ICU and 36% of ward patients, with similar frequencies between SARS-CoV-2 positive and negative patients (46.0% vs 46.8%, P = NS). A thyrotoxicosis pattern was observed in 14.6% SARS-CoV-2 ICU patients vs 7.7% in ICU negative (P = NS) and, overall in 8.8% of SARS-CoV-2 positive vs 7.4% of neg ative patients. In these patients, thyroglobulin levels were similar to those with normal thyroid function or NTIS. The hypothyroidism pattern was rare. Conclusions: NTIS pattern is common and relates to the severity of disease rather than SARS-CoV-2 infection. A thyrotoxicosis pattern is less frequently observed with similar frequency between patients with and without COVID-19. It is suggested that thyroid hormone monitoring in COVID-19 should not differ from other crit ically ill patients

Molecular Catalysis

The present work reports on the use of a hybrid blend of biopolymers as a matrix for lipase immobilization. (Hydroxypropyl)methyl cellulose (HPMC) and Chitosan (CS) were combined in order to formulate a film on which Mucor miehei lipase was immobilized. The biocatalyst was studied upon the model reaction of propyl laurate synthesis. The system was examined in terms of its capability to provide an appropriate environment where lipase will maintain its activity. The ratio of the polymers used was examined and HPMC:CS=2:1 proved to form the most promising matrix. Increasing the amount of the immobilized enzyme appears to improve the reaction yield indicating, however, mass transfer limitations. Apparent activation energy was calculated and energy input showed that ultra-sonication accelerated the initial rate of the reaction. Different reaction solvents were tested with isooctane being the most effective. The enzyme-containing film showed a remarkable reusability, since it can be used for up to 35 times without loss of activity. Finally, Atomic Force Microscopy (AFM) was performed to observe the morphology of the most promising films. The HPMC/CS film exhibits a nanostructure without a unique characteristic length and a roughness of 42.8 nm while the presence of enzyme smoothens the film as the roughness decreases to 5.5 nm

(Hydroxypropyl)methyl Cellulose-Chitosan Film as a Matrix for Lipase Immobilization. Part ΙΙ: Structural Studies

International audienceThe present work reports on the structural study of a film made of a hybrid blend of biopolymers used as an enzyme carrier. A cellulose derivative (HPMC) and chitosan (CS) were combined in order to formulate a film on which Mucor miehei lipase was immobilized. The film was successfully used as a biocatalyst; however, little is known about the structure of the system. Therefore, small-angle X-ray scattering, Fourier transform infrared spectroscopy (FTIR), optical microscopy, and scanning electron microscopy (SEM), as well as microindentation measurements, were used to shed light on the structure of the promising biocatalyst. Among the results, intermolecular hydrogen bonds were observed between the amide groups of the two polymers and the lipase. The presence of the enzyme does not seem to affect the mechanical properties of the matrix. The used film after 35 cycles of reaction seemed to be fatigued and had lost part of its humidity, explaining the reduction of the enzyme activity