Microgels and microbubbles based on poly(vinyl alcohol), PVA, are under investigation as injectable multimodal devices for controlled and targeted drug delivery, diagnostic imaging enhancement and in situ therapy. The performances in biomedicine of this synthetic macromolecule originate from its water affinity and networking capability, by physical interactions involving hydroxyl groups and/or by chemical cross-links. Having as a reference the PVA based microbubbles synthesized and characterized for biomedical applications in our laboratories,[1] we addressed atomistic molecular dynamics simulations at the aim to clarify structural and dynamical features of water and polymer in the external and internal interfacial domains of this system. A topologically extended model of the PVA network, with a high hydration and including six covalent junctions, has been at first developed to describe the region of the microbubble shell in contact with the surrounding aqueous medium. The air-shell interface at the microbubble core was modelled by considering PVA hydrated slabs centred in a vacuum box and containing different numbers of polymer chains (Figure 1). Simulation results show a strong attenuation of water mobility both in the bulk and interfacial region of the microbubble shell. The distribution of PVA at the air-shell interface is governed by the polymer surface concentration with a threshold value of about 14 μmol of residues/m2, which separates a regime of monolayer, quite rigid structures adsorbed on the surface and a regime of partially submerged globular aggregates, locally covered by thin water layers. Structural features of the interface in these models can explain the gas permeability and the reversibility of the dehydration/rehydration process of PVA microbubbles. The research leading to these results has received funding from the European Union Seventh Framework Programme FP7/2007-2013 under grant agreement n. 602923.
Chiessi, E., Tesei, G., Paradossi, G. (2014). Poly(vinyl alcohol) in Biomedical Devices: Insights from Molecular Dynamics Simulations. ??????? it.cilea.surplus.oa.citation.tipologie.CitationProceedings.prensentedAt ??????? Bringing Maths to Life, Naples.
Poly(vinyl alcohol) in Biomedical Devices: Insights from Molecular Dynamics Simulations
CHIESSI, ESTER;PARADOSSI, GAIO
2014-10-27
Abstract
Microgels and microbubbles based on poly(vinyl alcohol), PVA, are under investigation as injectable multimodal devices for controlled and targeted drug delivery, diagnostic imaging enhancement and in situ therapy. The performances in biomedicine of this synthetic macromolecule originate from its water affinity and networking capability, by physical interactions involving hydroxyl groups and/or by chemical cross-links. Having as a reference the PVA based microbubbles synthesized and characterized for biomedical applications in our laboratories,[1] we addressed atomistic molecular dynamics simulations at the aim to clarify structural and dynamical features of water and polymer in the external and internal interfacial domains of this system. A topologically extended model of the PVA network, with a high hydration and including six covalent junctions, has been at first developed to describe the region of the microbubble shell in contact with the surrounding aqueous medium. The air-shell interface at the microbubble core was modelled by considering PVA hydrated slabs centred in a vacuum box and containing different numbers of polymer chains (Figure 1). Simulation results show a strong attenuation of water mobility both in the bulk and interfacial region of the microbubble shell. The distribution of PVA at the air-shell interface is governed by the polymer surface concentration with a threshold value of about 14 μmol of residues/m2, which separates a regime of monolayer, quite rigid structures adsorbed on the surface and a regime of partially submerged globular aggregates, locally covered by thin water layers. Structural features of the interface in these models can explain the gas permeability and the reversibility of the dehydration/rehydration process of PVA microbubbles. The research leading to these results has received funding from the European Union Seventh Framework Programme FP7/2007-2013 under grant agreement n. 602923.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.