Free-Form Rapid Prototyped Porous PDMS Scaffolds Incorporating Growth Factors Promote Chondrogenesis

Abstract

In this study, we present a promising approach for the rapid development of porous polydimethylsiloxane (PDMS) scaffold prototypes, with outer geometry defined from the design stage, according to the form of conventional implants or adapted to patients' biostructures. The manufacture method is based on phase separation processes using materials obtained by casting within additive rapid prototyped molds. We include a comparative study of PDMS sponges obtained by different simple processes. Final in vitro assessment is carried out using hMSCs (bone marrow-derived human mesenchymal stem cells), cultured onto porous PDMS scaffolds functionalized with aminopropyltriethoxysilane (APTS) and equilibrated with a trophic factors medium produced by the cells. Results show that porous PDMS scaffold prototypes are excellent 3D platforms for hMSCs adhesion. Furthermore, this PDMS-3D niche, seeded with hMSCs and chondrogenic incubation medium during three weeks, showed a successful chondrogenesis determined by collagen type II expression. Thus, results show a versatile method to produce a 3D niche to address questions about cartilage and endochondral bone formation or skeleton tissues clinical approaches.

Composite scaffolds for osteochondral repair obtained by combination of additive manufacturing, leaching processes and hMSC-CM functionalization

“…The remarkable elasticity of the chondral phase can be appreciated in the lower image, in which the prototype can be seen gently compressed by a polymeric spatula. The range of pore sizes of the chondral phase is between 60 and 250 μm in diameter, the smaller pores consequence of trapped air bubbles and the larger ones conse quence of sugar leaching, showing results similar to previous studies [44]. It is important to note that the PDMS completely embeds two layers of the titanium lattice, thus avoiding the use of intermediate connecting elements or adhesives.…”

“…These results can be used for evaluating the equivalent Young moduli of the bony and chondral phases, for additional comparison with the biomaterials to be substituted. Simulation results lead to a Young modulus of the chondral phase of around 2 MPa, which corresponds to the typical order of magnitude of cartilage moduli measured in previous experi ences [50] and to characterization results from our initial studies linked to the manufacture of porous PDMS [44]. The Young modulus of the titanium lattice varies gradually from 2.7 GPa to 6.6 GPa, which is also in the range of the transitions from trabecular to cortical bone, which the lattice would aim to replace or repair.…”

“…The lattice scaffolds were UV irradiated, individually placed in 25 ml Falcon tubes and received the following treatment: i) wash using 0.5 ml PBS and 5 min centrifugation; ii) treatment with 2 M acetic acid during 20 min, rapid neutralization and PBS wash; iii) treatment with hMSC CM during 24 h or DMEM LG as control; and iv) scaffold seed with 150,000 hMSC and incubation in DMEM L 10% FBS during 48 h at 37°C in 5% CO 2 as early indicated [44,45]. Then, the lattice scaffolds were cut into smaller slices and pieces, individually placed in M24 tissue dishes, rinsed with ice cold PBS and fixed in 3.7% formaldehyde in PBS during 30 min at RT and washed in PBS.…”

Monolithic 3D labs- and organs-on-chips obtained by lithography-based ceramic manufacture

“…After 30 min in a cell incubator, the monolithic ceramic microsystems were exposed to a growth media of DMEM-LG plus 10%FBS during 3 days following some successful experiences. In short, the process follows previous research with some slight modifications [22,23].…”

Fabrication of scalable tissue engineering scaffolds with dual-pore microarchitecture by combining 3D printing and particle leaching

“…The published results have shown that freeze-drying cannot yield as large a range of pore dimensions as salt leaching, which can utilize salt crystals of various dimensions depending on the requirements. Currently various solid freeform (SFF) fabrication techniques such as stereolithography based printing have been reported to fabricate 3D porous scaffolds with well controlled pore size, porosity and mechanical properties using photo-crosslinkable materials [21,22]. Sacrificial moulds from SFF fabrication [11] or metallic wires [3,12,16,19] have been implemented for the generation of structured pores.…”