A novel pressed porous silicon-polycaprolactone composite as a dual-purpose implant for the delivery of cells and drugs to the eye

Abstract

Abbreviations: BSS ophthalmic balanced salt solution; DMEM Dulbecco's Modified Eagle's Medium; EGF epidermal growth factor; FBS fetal bovine serum; FDA fluorescein diacetate; PBS phosphate buffered saline; PCL polycaprolactone; pSi nanostructured porous silicon; SEM scanning electron microscopy; TEM transmission electron microscopy. To investigate loading of large-molecule biologics, murine BALB/c 3T3 cells, responsive to epidermal growth factor, insulin and transferrin, were seeded on composite materials. The cells showed significantly more proliferation at 48 h when seeded on composites loaded with these biologics, than on unloaded composites. No cell proliferation was observed on PCL alone, indicating the biologics had loaded into the pSi microparticles. Drug release, measured by ELISA for insulin, indicated a burst followed by a slower, continuous release over six days. When implanted under the rat conjunctiva, the most promising composite material did not cause significant neovascularization but did elicit a macrophage and mild foreign body

Preparación y caracterización de membranas poliméricas electrohiladas de policaprolactona y quitosano para la liberación controlada de clorhidrato de tiamina / Preparation and Characterization of Electrospun Polymeric Membranes of Polycaprolactone and Chitosan for Controlled Release of Thiamine Chlorhydrate

“…Otros autores evaluaron cómo las diferentes concentraciones de PCL y dipiridamo (DIP) con la técnica del electrohilado, afecta a las propiedades estructurales y físicas de las fibras (Repanas y Glasmacher [10]). De otro lado Irani et al [11], evaluaron la carga y liberación de pequeñas moléculas y macromoléculas de fármacos en materiales compuestos de silicio poroso nanoestructurado y policaprolactona (PSI-PCL) prensadas, y su capacidad para soportar la unión de células de mamíferos y su crecimiento. De la misma manera otros estudios indican, que una mezcla de poli(ε-caprolactona) (PCL) y poli(óxido de etileno) (PEO) se electrohilaban para producir mallas fibrosas que podían liberar un fármaco proteico de una manera controlada.…”

Oral Mucosal Epithelial Cells Grown on Porous Silicon Membrane for Transfer to the Rat Eye

“…We considered that small pieces of pSi membrane might have potential for the construction of an artificial niche because of their ease of fabrication from inorganic silicon, biocompatibility within the eye, capacity for surface modification, and ability to support mammalian cell attachment and growth 40 – 43 . The porous structure mimics to some extent the retes of the palisades of Vogt, and lends the material a large surface area into which bioactive factors can be loaded.…”

“…Whole eyes were removed from rats 8 weeks post-pSi implantation, fixed in 10% buffered formalin, embedded in paraffin wax, sectioned and stained with haematoxylin and eosin 40 . All sections were assessed by a qualified pathologist (SK).…”

“…Porous silicon (pSi) 23 exhibits some potential as a scaffold in regenerative medicine 24 – 28 . Psi membranes are inorganic, allowing efficient sterilization 29 , are biocompatible in vitro 25 , 30 – 32 and in vivo 30 , 33 , degrade to non-toxic silicic acid 34 , can be surface-modified to improve degradation 35 – 37 and attachment of cells 38 , 39 , and can be loaded with proteins and growth factors 40 . We have previously shown that human corneal epithelial cells can be grown on pSi membranes coated with rat tail collagen, and that aminosilanised pSi membranes implanted under the rat conjunctiva do not erode the surrounding tissue 41 .…”

Hybrid polymer/porous silicon nanofibers for loading and sustained release of synthetic DNA-based responsive devices

“…Mesoporous silicon has been extensively studied for drug delivery applications due to its biodegradability, its biocompatibility, and its large surface area and pore volume available for drug loading. [27][28][29][30][31] Mesoporous silicon containing various therapeutic or diagnostic payloads has been combined with polymer systems, [32][33][34][35][36][37][38][39][40][41][42] and these constructs have shown promise for biomedical imaging and drug delivery applications. Of relevance to the present work, porous silicon nanoparticles (pSiNPs) have been shown to protect bioactivity of proteins 43 and nucleic acids, [44][45][46][47] and protein-loaded pSiNPs have been incorporated into biocompatible polymers in the form of nanofibers using a voltage-free nebulization fabrication method, creating a protective shell that maintained active protein release for 60 days in vitro.…”