1,720,976 research outputs found
Functionalized biocompatible polyelectrolyte multilayers for drug delivery: In situ investigation of mechanical properties by dissipative quartz crystal microbalance
No full textNanostructured polymeric capsules have been applied in different fields, and specifically are regarded as promising for smart drug delivery applications. The physical-chemical and mechanical properties, and thus the permeability of the polyelectrolyte multilayer shell, play an important role in efficient delivery. Quartz crystal microbalance working in liquid has been used for the characterization of the buildup process and of the viscoelastic properties of biocompatible multilayers and of their functionalization by S-layer proteins. Optical and scanning electron microscopy have been used for the morphological characterization of nanostructured capsules obtained at physiological conditions by the assembly of the characterized multilayers onto spherical cores and by their subsequent removal. The proposed functionalized biocompatible capsules can be regarded as promising candidates for smart drug delivery application
Polyelectrolyte based molecular carriers : The role of self-assembled proteins in permeability properties.
No full textPolyelectrolyte capsules are seen as promising nanotechnology based drug delivery systems. In previous works, we have demonstrated the possibility to fabricate bio-activated surface layer containing capsules with improved features in terms of biocompatibility. In this study, we have characterized the permeability properties of such capsules towards low and high molecular weight molecules, including proteins. The results indicated that the presence of the surface layer strongly affects the permeability properties of the capsules in terms of loading capacity which was found to be higher compared to that of plain capsules. These properties make such systems interesting candidates as drug delivery platforms
Polyelectrolyte multilayers and capsules: S-layer functionalization for improving stability and biocompatibility
No full textRecent advances in medicine and biotechnology have brought about the need to develop nano-engineered delivery systems that can encapsulate a wide variety of therapeutics and that could allow their targeted delivery and sustained release. Nanostructured polyelectrolyte multilayers (NPMs) and capsules (NPCs), fabricated by electrostatic layer-by-layer (LbL) technique have been proposed for the functionalization of biomaterials and as delivery systems. This paper focuses on the degradation and biocompatibility characterization of NMPs and NPCs functionalized with bacterial self-assembled proteins (S-Layers). S-layers have been proposed as an efficient strategy for the functionalization of NPMs and NPCs. In present work, S-layers were recrystallized on mica and imaged by atomic force microscopy. The LbL assembly and the stability of cationic poly (allylamine hydrochloride) and anionic sodium poly (styrene sulfonate) multilayers functionalized with a terminal S-Layer were investigated by means of quartz crystal microbalance. In order to evaluate the impact of S-layer functionalization on the degradation of NPCs, S-Layer functionalized NPCs were characterized in vitro in terms of cell morphology and viability. The results revealed the role of S-layers in decreasing component release from NPMs and thus in increasing release time from NPCs
Nanoengineered polymeric S-layers based capsules with targeting activity
No full textNanostructured polymeric capsules are regarded as highly promising systems with different potential applications ranging from drug delivery, biosensing and artificial cells. To fully exploit this potential, it is required to produce bio-activated stable and biocompatible capsules. To this purpose, in present work we proposed the combination of the layer-by-layer self assembly method with bacterial S-layer technology to fabricate stable and biocompatible polymeric capsules having a well defined arrangement of functional groups allowing the covalent attachment of antibody molecules. Hollow microcapsules were obtained by the layer-by-layer self assembly of oppositely charged polyelectrolytes onto colloidal particles, followed by removal of the cores at acidic pH. S-layers were crystallized onto the shell of the obtained capsules. Quartz crystal microbalance was used to characterize the crystallization process onto planar surfaces. S-layer containing capsules were investigated by atomic force microscopy. Immunoenzymatic tests were performed to assess the effective modification of the S-layer with antibody molecules both on planar surfaces and on hollow capsules. Fluorescent microscopy was employed to visualize the presence of the antibody molecules onto the capsule shell and immunological tests used to assess the bioactivity of the immobilized antibodies. Finally, the in vitro cytotoxicity of fabricated S-layer containing capsules was studied. The obtained results demonstrated the possibility to fabricate bio-activated S-layer containing capsules with improved features in terms of biocompatibility
Development of nanostructured magnetic capsules by means of the layer by layer technique
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