Three-dimensional photopatterning of hydrogels using stereolithography for long-term cell encapsulation

Abstract

Cell-encapsulated hydrogels with complex three-dimensional (3D) structures were fabricated from photopolymerizable poly(ethylene glycol) diacrylate (PEGDA) using modified 'top-down' and 'bottoms-up' versions of a commercially available stereolithography apparatus (SLA). Swelling and mechanical properties were measured for PEGDA hydrogels with molecular weights (M(w)) ranging from 700 to 10 000 Daltons (Da). Long-term viability of encapsulated NIH/3T3 cells was quantitatively evaluated using an MTS assay and shown to improve over 14 days by increasing the M(w) of the hydrogels. Addition of adhesive RGDS peptide sequences resulted in increased cell viability, proliferation, and spreading compared to pristine PEG hydrogels of the same M(w). Spatial 3D layer-by-layer cell patterning was successfully demonstrated, and the feasibility of depositing multiple cell types and material compositions into distinct layers was established.

Controlled Synthesis of Cell-Laden Microgels by Radical-Free Gelation in Droplet Microfluidics

“…Hence, we assume that not only the macroscopic gel stiffness but also the nanoscale obstruction of the diffusion of nutrients and metabolites, which arises due to the presence of the polymer matrix, is an important factor for the cell viability. On the basis of our results and in agreement with the work of Bashir et al, 26 this obstruction seems to be more pronounced in the PEG 1.5 kDa microgels than in the PEG 6.0 kDa microgels.…”

Fabrication of Hydrogel Particles of Defined Shapes Using Superhydrophobic‐Hydrophilic Micropatterns

“…Top-down approaches control the microscale features (i.e. size and shape) of relatively large pieces of bulk hydrogels, 4 whereas bottom-up approaches aim to generate larger tissue constructs via the assembly of smaller building blocks (usually cell-laden hydrogels) which mimic the in vivo tissue structure of repeating functional units. 5 The limitations of bulk hydrogels are that they usually lack the hierarchical architecture of in vivo tissues and suffer from the slow diffusion of nutrients and other biological signaling molecules (e.g., growth factors) from the surrounding medium into the entrapped cells, leading to higher toxicity and incompatibility with long-term cell cultivation.…”

A 3D-printed platform for modular neuromuscular motor units

“…The design and fabrication of an instructive environment for this cellular system were easily achieved with the use of stereolithographic 3D printing 24,25 . This manufacturing technology has been widely utilized for applications in tissue engineering, not only due to the user's control over the specific design, geometric, and mechanical parameters but also for its ability to fabricate biomaterials (hydrogels whose properties can mimic cells' natural micro-environments) and encapsulate various cell types in three dimensions 32,33 in a short time frame and over a range of length scales.…”