Shape-Defining Scaffolds for Minimally Invasive Tissue Engineering

Abstract

Shaped hydrogels, formed by covalently cross-linking, can be structurally collapsed into smaller, temporary shapes that permit their minimally invasive delivery in vivo. The rapid recovery of scaffold properties facilitates efficient cell seeding in vivo and permits neotissue formation in desired geometries.

Active scaffolds for on-demand drug and cell delivery

“…S1 and Movies S1, S2, and S3). This finding agrees with the earlier reports on alginate macroporous gels (40,41). Highly monodisperse iron oxide nanoparticles with a diameter ∼10 nm were embedded in the gel at predetermined concentrations (Fig.…”

“…1A) can readily be fabricated to accommodate specific applications. Pores with controlled sizes and connectivity were introduced into the ferrogels by freezing gels at different temperatures prior to lyophilization (40). Corresponding to freezing temperatures of −20, −80, and −180°C, the average diameters of the pores were 700, 300, and 20 μm.…”

“…Alginate gels were covalently cross-linked with adipic acid dihydrazide (AAD) (Fig. 1D) (40), because the covalent cross-links allowed gels to maintain the macroporous structure following lyophilization and subsequent rehydration. Peptides containing the RGD amino acid sequence were covalently coupled to the polymer prior to gel formation ( Fig.…”

“…1C), and lower modulus (Fig. S2) were chosen because (i) drug and cell transport will presumably be more efficient in scaffolds with larger pore sizes and better connectivity (40), (ii) a higher iron-oxide-particle density gives a higher body force under the same magnetic field, and (iii) a gel with lower modulus tends to deform more when subject to the same body forces. Large deformation of the gel leads to more pronounced effects on drug and cell release.…”

Self-Actuated, Thermo-Responsive Hydrogel Valves for Lab on a Chip

“…Since then, hydrogels have been extensively used in medicine [20], pharmaceuticals [21,22] and tissue engineering [23]. The potential ability of hydrogels to control the transport of fluids was also recognized.…”