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Online seminar by Jun. Ann-Christin Pöppler: 'Insights into structure and properties of loaded polymer nanoparticles by (solid-state) NMR spectroscopy - looking behind the scenes and into the future' (Lecture)

Thursday 17 December 2020Add to my calendar
from 13:00
Jun.-Prof. Ann-Christin Pöppler, Organic Structural Chemistry, Institute of Organic Chemistry, University of Würzburg (Germany)

The lecture will be divided into two parts: research and education.

Research Lecture on "Insights into structure and properties of loaded polymer nanoparticles by (solid-state) NMR spectroscopy - looking behind the scenes and into the future".

Despite the large number of publications related to drug delivery, recent (critical) comments identified a gap between academic research and benefit to the patient.[1] To overcome this gap, multidisciplinary joint efforts are required. Improved structural understanding of nanoparticle drug delivery systems can be one such approach. While previously the view on such nanoparticles was dominated by the look from the outside, recent advances have provided access to molecular level structural information, which can be correlated with interesting physicochemical properties.[2]

In this context, (solid-state) NMR spectroscopy is a very versatile toolbox, which will be showcased based on two examples of polymeric micelles loaded with curcumin as a proof-of-concept study and loaded with the important, yet chemically more complex anti-cancer drug paclitaxel.

Through different NMR experiments complemented by quantum chemical calculations, insight into the conformation of guest molecules and key intermolecular interactions is gained. Experimental evidence for the involvement of both the hydrophobic as well as the hydrophilic(!) polymer building blocks in the coordination of curcumin was obtained. With this information it is possible to (i) hypothesize a loading mechanism, (ii) explain pharmaceutically relevant dissolution rates and subsequently derive ideas for improved polymeric carrier materials.[3] Despite the strong signal overlap expected for large guest molecules such as paclitaxel, heteronuclear correlation experiments such as 14N-1H HMQC experiments can disperse the signals over a broader shift range and yield valuable information on intermolecular interactions as well as the symmetry of the nitrogen environments.[4]

A short teaser on NMR in simulated gastrointestinal fluids will serve as a transition to present future research ideas and perspectives to develop and expand modern NMR spectroscopy in a) material science/drug delivery and b) in the medical context towards disease relevant conditions.

[1] J.-C. Leroux, Angew. Chem. Int. Ed. 201756, 15170-15171.

[2] M. H. Stenzel, Angew. Chem. Int. Ed.doi.org/10.1002/anie.202010934.

[3] A.-C. Pöppler, M. M. Lübtow, J. Schlauersbach, J. Wiest, L. Meinel, R. Luxenhofer, Angew. Chem. Int. Ed. 201958, 18540-18546.

[4] M. Grüne, R. Luxenhofer, D. Iuga, S. P. Brown, A.-C. Pöppler, J. Mater. Chem. B 20208, 6827-6836.

Teaching Lecture on "Nucleophilic Aromatic Substitution Reactions"

This 20 min teaching example on "Nucleophilic Aromatic Substitution" is embedded in the undergraduate teaching in organic chemistry, specifically within the topic of aromatic molecules and their chemistry. At this stage, the students have already learnt how to identify aromatic systems, that they usually react via an electrophilic aromatic substitution mechanism and they have been introduced to heteroaromatic molecules.

In this subsequent step, the contents from the previous chapters as well as the concept of rate determining steps are transferred to nucleophilic aromatic substitution reactions with the aim of discussing the reaction mechanism, reactivities and regioselectivities. This will be complemented by applications to and implications for research and daily life.

prof. Jana Roithova & prof. Arno Kentgens

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