Injectable Biomaterials for Regenerating Complex Craniofacial Tissues

Abstract

Engineering complex tissues requires a precisely formulated combination of cells, spatiotemporally released bioactive factors, and a specialized scaffold support system. Injectable materials, particularly those delivered in aqueous solution, are considered ideal delivery vehicles for cells and bioactive factors and can also be delivered through minimally invasive methods and fill complex 3D shapes. In this review, we examine injectable materials that form scaffolds or networks capable of both replacing tissue function early after delivery and supporting tissue regeneration over a time period of weeks to months. The use of these materials for tissue engineering within the craniofacial complex is challenging but ideal as many highly specialized and functional tissues reside within a small volume in the craniofacial structures and the need for minimally invasive interventions is desirable due to aesthetic considerations. Current biomaterials and strategies used to treat craniofacial defects are examined, followed by a review of craniofacial tissue engineering, and finally an examination of current technologies used for injectable scaffold development and drug and cell delivery using these materials.

Cell encapsulation using biopolymer gels for regenerative medicine

“…Ceramic, metallic and polymeric materials have been investigated widely for the direct replacement of tissues with good success (Zhang and Webster 2009). While the majority of licensed treatments consist of a synthetic material alone, there is a current trend towards the delivery of cells within the material matrix in order to expedite healing (Kretlow et al 2009). Much of this work has involved the use of sponge-like scaffold materials exhibiting interconnected porosity (Rosa et al 2008).…”

Bone Regeneration Potential of Stem Cells Derived from Periodontal Ligament or Gingival Tissue Sources Encapsulated in RGD-Modified Alginate Scaffold

“…15,16 Studies have confirmed that providing a suitable microenvironment for MSC proliferation and differentiation in response to exogenous stimuli and growth factors is a critical step toward clinical applications. [17][18][19][20][21][22][23] Several types of scaffolds have been used to support growth and differentiation of progenitor cells for bone regeneration, including natural polymers (e.g., alginates). 23,24 Alginates are natural heteropolysaccharides that are isolated from brown sea algae.…”

Tuning the gelation of thermoresponsive gels

“…the solid phase becomes dominant) 10 as shown in Fig 3. When increasing the temperature syneresis is often observed where liquid is also present with the gel, a phenomenon that was first reported by Graham in 1864 when observing gelatine solutions. 11 TRGs have many biomedical applications 12 including drug delivery [13][14][15][16][17][18][19][20][21] and tissue engineering as in-situ forming gels [22][23][24][25][26][27] and in 3-D bioprinting. [28][29][30][31] Furthermore with the increasing recent interest in 3-D printable materials and the need to control the rheology of the solution while printing 32, 33 the areas of potential usage of TRGs has increased since 3-D printing is applied to the manufacture of materials in various industries besides the medical industry, like aerospace, automotive, building and construction, marine, food industry and in manufacturing electronic and optical devices.…”