Channeled Scaffolds Research Articles

Branched Channel Scaffolds Fabricated by SFF for Direct Cell Growth Observations

A β-TCP scaffold with a branched channel system was designed to create a novel micro-device that allowed culture perfusion and direct time observation of the cells attached. The scaffold was made by indirect solid free form fabrication (SFF) technology. The flow channel structure was exposed so that the perfusion of the mesenchymal stem cell (MSC) culture could be viewed directly. The cell-seeded scaffolds were continuously perfused for 7 days in the micro-device; during this time, it was possible to observe the dynamic culture processes with cells adhering to the scaffolds and real time cell growth directly. This concept has great potential for use in bone tissue engineering and for versatile fabrication of enhanced scaffolds.

Biomimetic Approach to Cardiac Tissue Engineering: Oxygen Carriers and Channeled Scaffolds

Biomimetic Approach to Cardiac Tissue Engineering: Oxygen Carriers and Channeled Scaffolds

Biomimetic Approach to Cardiac Tissue Engineering: Oxygen Carriers and Channeled Scaffolds

We report that the functional assembly of engineered cardiac muscle can be enhanced by oxygen supply provided by mechanisms resembling those in normal vascularized tissues. To mimic the capillary network, cardiomyocytes and fibroblasts isolated from the neonatal rat hearts were cultured on a highly porous elastomer with a parallel array of channels that were perfused with culture medium. To mimic oxygen supply by hemoglobin, culture medium was supplemented with a perfluorocarbon (PFC) emulsion; constructs perfused with unsupplemented culture medium served as controls. In PFC-supplemented medium, the decrease in the partial pressure of oxygen in the aqueous phase was only 50% of that in control medium (28 mmHg vs. 45 mmHg between the construct inlet and outlet at a flow rate of 0.1 mL/min). Consistently, constructs cultivated in the presence of PFC contained higher amounts of DNA and cardiac markers (troponin I, connexin-43) and had significantly better contractile properties as compared to control constructs. In both groups, electron microscopy revealed open channels and the presence of cells at the channel surfaces as well as within constructs. Improved properties of cardiac constructs could be correlated with the enhanced supply of oxygen to the cells, by a combined use of channeled scaffolds and PFC.

Fiber templating of poly(2-hydroxyethyl methacrylate) for neural tissue engineering

We have developed a method to create longitudinally oriented channels within poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels for neural tissue engineering applications. Incorporated into an entubulation strategy, these scaffolds have the potential to enhance nerve regeneration after transection injuries of either the spinal cord or the peripheral nerve by increasing the available surface area and providing guidance to extending axons and invading cells. The fabrication process is straightforward and the resultant scaffolds are highly reproducible. Polycaprolactone (PCL) fibers were extruded and embedded in transparent, crosslinked pHEMA gels. Sonication of the pHEMA/PCL composite in acetone resulted in the complete dissolution of the PCL, leaving longitudinally oriented, fiber-free channels in the pHEMA gel. Regulating the size and quantity of the PCL fibers allowed us to control the diameter and number of channels. Small and large channel scaffolds were fabricated and thoroughly characterized. The small channel scaffolds had 142±7 channels, with approximately 75% of the channels in the 100–200 μm size range. The large channel scaffolds had 37±1 channels, with approximately 77% of the channels in the 300–400 μm range. The equilibrium water content (EWC), porosity and compressive modulus were measured for each of the structures. Small and large channel scaffolds had, respectively, EWCs of 55.0±1.2% and 56.2±2.9%, porosities of 35±1% and 40±1% and compressive moduli of 191±7 and 182±4 kPa.