Molecular level characterisation of the surface of carbohydrate-functionalised mesoporous silica nanoparticles (MSN) as a potential targeted drug delivery system via high resolution magic angle spinning (HR-MAS) NMR Spectroscopy

Atomistic level characterisation of external surface species of mesoporous silica nanomaterials (MSN) poses a significant analytical challenge due to the inherently low content of grafted ligands. This study proposes the use of HR-MAS NMR spectroscopy for a molecular level characterisation of the external surface of carbohydrate-functionalised nanoparticles. MSN differing in size (32 nm, 106 nm, 220 nm) were synthesised using the sol-gel method. The synthesised materials displayed narrow particle size distribution (based on DLS and TEM results) and a hexagonal arrangement of the pores with a diameter of ca. 3 nm as investigated with PXRD and N2 physisorption. The surface of the obtained nanoparticles was functionalised with galactose and lactose using reductive amination as confirmed by FTIR and NMR techniques. The functionalisation of the particles surface did not alter the pore architecture, structure or morphology of the materials as confirmed with TEM imaging. HR-MAS NMR spectroscopy was used for the first time to investigate the structure of the functionalised MSNs suspended in D2O. Furthermore, lactose was successfully attached to the silica without breaking the glycosidic bond. The results demonstrate that HR-MAS NMR can provide detailed structural information on the organic functionalities attached at the external surface of MSN within short experimental times

Evaluation of the influence of physiotherapy on a standing balance in a group of patients after cerebral stroke, determined on a basis of posturographic examination

Cel. Celem pracy jest ocena wpływu rehabilitacji metodą PNF (Prorioceptive Neuromuscular Facilitation - torowanie nerwowo-mięśniowe) na poprawę równowagi pacjentów po udarze mózgu oraz ocena równowagi w zależności od wieku, strony niedowładu, okresu od wystąpienia udaru na podstawie badań posturograficznych. Materiał i metody. Badaniem objęto 32 pacjentów po udarze mózgu poddanych 12-tygodniowej rehabilitacji metodą PNF w Zakładzie Rehabilitacji Szpitala Uniwersyteckiego w Krakowie. Grupę badawczą stanowiło 8 kobiet i 24 mężczyzn w wieku od 25 do 73 lat. W celu oceny skuteczności terapii i jej wpływu na poprawę parametrów równowagi przeprowadzono dwukrotne badanie stabilności posturalnej na platformie posturograficznej: w pierwszym i ostatnim dniu terapii. Badanie wykonano przy oczach otwartych i zamkniętych oraz w warunkach sprzężenia zwrotnego. Zestaw badanych parametrów obejmował: średni promień wychyleń, pole powierzchni statokinezjogramu, długość drogi przebytej przez środek ciężkości oraz koordynację.Wyniki. Na podstawie przeprowadzonej analizy stwierdzono istotnie statystycznie zmiany wszystkich parametrów całej badanej grupy (poziom istotności p. 0,05). Porównując wyodrębnione grupy, można stwierdzić istotną statystycznie poprawę wybranych parametrów równowagi po terapii w grupie chorych do 59. roku życia, w grupie chorych do 12. miesiąca od udaru i w grupie z lewostronnym niedowładem. Wnioski. Fizjoterapia metodą PNF wpływa na poprawę równowagi w pozycji stojącej u pacjentów po udarze mózgu, co potwierdzają wyniki uzyskane w badaniu posturograficznym. Wydaje się, że posturografia pozwala na obiektywną ocenę postawy ciała pacjentów po udarze mózgu.Aim. The aim of this study was to evaluate the influence of the PNF method (Proprioceptive Neuromuscular Facilitation) on a balance improvement in a group of patients after the stroke, as well as to evaluate the influence of age, side of paresis and time elapsed from a stroke on balance disorders in this group. Material and methods. The examination of 32 stroke patients, who participated in a 12-week rehabilitation session with the PNF method, was carried out at the Rehabilitation Unit of University Hospital in Krakow. The group consisted of 8 women and 24 men, in the age of 25 to 73. In order to assess the therapy effectiveness, posturography measurements were performed before and after therapy course. The posturographic test was performed with open and closed eyes and with the feedback conditions. The examined parameters were: average radius of deflection, area of the statokinesiogram surface, lengths of the distance covered by the gravity center, as well as parameters of coordination. Results. Statistically significant (p . 0,05) change was observed in all tested parameters measured before and after therapy in an entire group of patients. The statistically significant improvement was noticed after therapy in the group of stroke patients younger than 59 years old, in a group under 12 months after stroke and also in a group with left hemiparesis. Conclusions. Physiotherapy conducted by PNF method improves the body balance in case of patients subjected to cerebral strokes, what was confirmed by posturographic examinations. It seems that the posturography allows for the objective assessment of the posture stability in stroke patients

Unravelling the mechanisms of drugs partitioning phenomena in micellar systems via NMR spectroscopy

Despite extensive use of micelles in materials and colloidal science, their supramolecular organization as well as host-guest interactions within these dynamic assemblies are poorly understood. Small guest molecules in the presence of micelles undergo constant exchange between a micellar aggregate and the surrounding solution, posing a considerable challenge for their molecular level characterisation. In this work we reveal the interaction maps between small guest molecules and surfactants forming micelles via novel applications of NMR techniques supported with state-of-the-art analytical methods used in colloidal science. Model micelles composed of structurally distinct surfactants (block non-ionic polymer Pluronic® F-127, non-ionic surfactant Tween 20 or Tween 80 and ionic surfactant SLS, sodium lauryl sulphate) were selected and loaded with model small molecules of biochemical relevance (i.e. the drugs fluconazole, FLU or indomethacin, IMC) known to have different partition coefficients. Molecular level organization of FLU or IMC within hydrophilic and hydrophobic domains of micellar aggregates was established using the combination of NMR methods (1D 1H NMR, 1D 19F NMR, 2D 1H-1H NOESY and 2D 1H-19F HOESY, and the multifrequency-STD NMR) and corroborated with molecular dynamics (MD) simulations. This is the first application of multifrequency-STD NMR to colloidal systems, enabling us to elucidate intricately detailed patterns of drug/micelle interactions in a single NMR experiment within minutes. Importantly, our results indicate that flexible surfactants, such as block copolymers and polysorbates, form micellar aggregates with a surface composed of both hydrophilic and hydrophobic domains and do not follow the classical core-shell model of the micelle. We propose that the magnitude of the changes in 1H chemical shifts corroborated with interaction maps obtained from DEEP-STD NMR and 2D NMR experiments can be used as an indicator of the strength of the guest-surfactant interactions. This NMR toolbox can be adopted for the analysis of the broad range of colloidal host-guest systems from soft materials to biological systems