in vitro development of bioimplants made up of elastomeric scaffolds with peptide gel filling seeded with human subcutaneous adipose tissue-derived progenitor cells

Rapid Prototyping Technologies: 3D Printing Applied in Medicine

Three-dimensional printing technology has been used for more than three decades in many industries, including the automotive and aerospace industries. So far, the use of this technology in medicine has been limited only to 3D printing of anatomical models for educational and training purposes, which is due to the insufficient functional properties of the materials used in the process. Only recent advances in the development of innovative materials have resulted in the flourishing of the use of 3D printing in medicine and pharmacy. Currently, additive manufacturing technology is widely used in clinical fields. Rapid development can be observed in the design of implants and prostheses, the creation of biomedical models tailored to the needs of the patient and the bioprinting of tissues and living scaffolds for regenerative medicine. The purpose of this review is to characterize the most popular 3D printing techniques.

Culturing Mammalian Cells in Three-dimensional Peptide Scaffolds

A useful technique for culturing cells in a self-assembling nanofiber three-dimensional (3D) scaffold is described. This culture system recreates an environment that closely mimics the structural features of non-polarized tissue. Furthermore, the particular intrinsic nanofiber structure of the scaffold makes it transparent to visual light, which allows for easy visualization of the sample under microscopy. This advantage was largely used to study cell migration, organization, proliferation, and differentiation and thus any development of their particular cellular function by staining with specific dyes or probes. Furthermore, in this work, we describe the good performance of this system to easily study the redifferentiation of expanded human articular chondrocytes into cartilaginous tissue. Cells were encapsulated into self-assembling peptide scaffolds and cultured under specific conditions to promote chondrogenesis. Three-dimensional cultures showed good viability during the 4 weeks of the experiment. As expected, samples cultured with chondrogenic inducers (compared to non-induced controls) stained strongly positive for toluidine blue (which stains glycosaminoglycans (GAGs) that are highly present in cartilage extracellular matrix) and expressed specific molecular markers, including collagen type I, II and X, according to Western Blot analysis. This protocol is easy to perform and can be used at research laboratories, industries and for educational purposes in laboratory courses.

Biocompatible Porous Polyester-Ether Hydrogel Scaffolds with Cross-Linker Mediated Biodegradation and Mechanical Properties for Tissue Augmentation

Porous polyester-ether hydrogel scaffolds (PEHs) were fabricated using acid chloride/alcohol chemistry and a salt templating approach. The PEHs were produced from readily available and cheap commercial reagents via the reaction of hydroxyl terminated poly(ethylene glycol) (PEG) derivatives with sebacoyl, succinyl, or trimesoyl chloride to afford ester cross-links between the PEG chains. Through variation of the acid chloride cross-linkers used in the synthesis and the incorporation of a hydrophobic modifier (poly(caprolactone) (PCL)), it was possible to tune the degradation rates and mechanical properties of the resulting hydrogels. Several of the hydrogel formulations displayed exceptional mechanical properties, remaining elastic without fracture at compressive strains of up to 80%, whilst still displaying degradation over a period of weeks to months. A subcutaneous rat model was used to study the scaffolds in vivo and revealed that the PEHs were infiltrated with well vascularised tissue within two weeks and had undergone significant degradation in 16 weeks without any signs of toxicity. Histological evaluation for immune responses revealed that the PEHs incite only a minor inflammatory response that is reduced over 16 weeks with no evidence of adverse effects.