A novel fabrication method of macroporous biodegradable polymer scaffolds using gas foaming salt as a porogen additive

Abstract

Highly open porous biodegradable poly(L-lactic acid) ¿PLLA scaffolds for tissue regeneration were fabricated by using ammonium bicarbonate as an efficient gas foaming agent as well as a particulate porogen salt. A binary mixture of PLLA-solvent gel containing dispersed ammonium bicarbonate salt particles, which became a paste state, was cast in a mold and subsequently immersed in a hot water solution to permit the evolution of ammonia and carbon dioxide within the solidifying polymer matrix. This resulted in the expansion of pores within the polymer matrix to a great extent, leading to well interconnected macroporous scaffolds having mean pore diameters of around 300-400 microm, ideal for high-density cell seeding. Rat hepatocytes seeded into the scaffolds exhibited about 95% seeding efficiency and up to 40% viability at 1 day after the seeding. The novelty of this new method is that the PLLA paste containing ammonium bicarbonate salt particles can be easily handled and molded into any shape, allowing for fabricating a wide range of temporal tissue scaffolds requiring a specific shape and geometry.

Preparation of interconnected poly(ε-caprolactone) porous scaffolds by a combination of polymer and salt particulate leaching

“…It was carried out by dissolving a gas at elevated pressure (physical blowing agent) [11][12][13] or by incorporated a chemical that yields gaseous decomposition products (chemical blowing agent) [14][15][16]. The foaming technique generally leads to pore structures that are not as fully interconnected as the previously mentioned ones.…”

“…Another feature is the 'skin-core' structure where the core is porous while the external skin of the sample is solid. In some cases, the resulting scaffolds can have well interconnected macroporous structure with limited core/skin effect [15]. Other techniques include the use of particle aggregation to create macroporous three-dimensional structures with porosity up to 35% [17][18][19] and solid freeform fabrication technique (SFF) such as 3D-printing [20], selective laser sintering [21], 3D-plotting [22], fused deposition modeling [2,23].…”

FORMULASI MIKROPARTIKEL BERPORI DALAM POLI (D,L-Laktida) SEBAGAI SCAFFOLDDENGAN TEKNIK EMULSIFIKASI PENGUAPAN PELARUT

“…Stuktur open porous dengan interkoneksi pori yang baik dalam scaffold dibutuhkan tidak hanya untuk mengakomodasi sel dalam jumlah yang cukup tetapi juga untuk memfasilitasi transport nutrisi dan oksigen [1,2] . PDLLA telah digunakan untuk pembentukkan biodegradabel scaffold karena kemampuan biodegradasi yang terkontrol dan biokompatibilitas yang baik [3,4,5] .…”

Solute Transport in Cyclically Deformed Porous Tissue Scaffolds with Controlled Pore Cross-Sectional Geometries

“…The need for scaffolds with an adequate balance between mechanical and mass transport properties thus requires the ability to precisely control the scaffold topology. 47 In contrast to commonly used methods to create porous sponges of scaffold materials (e.g., particulate leaching 48,49 or gas foaming 50 ), the solid freeform technique used in this study allows the fabrication of scaffolds with programmable pore labyrinths. Designer-scaffolds have more predictable mechanical properties, mass transport rates, and spatial distributions than do scaffolds generated with such traditional methods.…”