Continuous digital light processing (cDLP): Highly accurate additive manufacturing of tissue engineered bone scaffolds

Abstract

Highly accurate rendering of the external and internal geometry of bone tissue engineering scaffolds effects fit at the defect site, loading of internal pore spaces with cells, bioreactor-delivered nutrient and growth factor circulation, and scaffold resorption. It may be necessary to render resorbable polymer scaffolds with 50 μm or less accuracy to achieve these goals. This level of accuracy is available using Continuous Digital Light processing (cDLP) which utilizes a DLP® (Texas Instruments, Dallas, TX) chip. One such additive manufacturing device is the envisionTEC (Ferndale, MI) Perfactory®. To use cDLP we integrate a photo-crosslinkable polymer, a photo-initiator, and a biocompatible dye. The dye attenuates light, thereby limiting the depth of polymerization. In this study we fabricated scaffolds using the well-studied resorbable polymer, poly(propylene fumarate) (PPF), titanium dioxide (TiO2) as a dye, Irgacure® 819 (BASF [Ciba], Florham Park, NJ) as an initiator, and diethyl fumarate as a solvent to control viscosity.

Mechanical modulation of nascent stem cell lineage commitment in tissue engineering scaffolds

“…A number of different manufacturing methods are currently in use to produce scaffolds [22-43]. While many meet rigorous technical performance specifications [22-44], even the best manufacturing methods are not perfect and include defined design tolerances for optimal performance.…”

“…The scaffolds used in this study were prepared via Continuous-Digital Light Processing (cDLP) Additive Manufacturing (AM) technology (Perfactory® Mini Multi Lens, envisionTEC, Ferndale, MI), configured for 21 μm × 21 μm × 50 μm (xyz) resolution. Scaffolds were produced from a light polymerizable polymer, poly(propylene fumarate) (PPF), with which our group has significant experience [43]. …”

3D printing of resorbable poly(propylene fumarate) tissue engineering scaffolds

“…23 , 24 Sheet-like structures can be prepared as solids or weaves from fi bers, such as in electrospinning. 25 -27 Three-dimensional polymer scaff old printing The two primary 3D printing modalities are laser sintering 28 and photocross-linking, 29 with the latter holding promise for the highest resolution (see the Introductory article in this issue). We review the commonly used 3D printing techniques for preparing polymer scaffolds.…”

The Potential Impact of Bone Tissue Engineering in the Clinic

“…Most 3D printing of BTE scaffolds has been studied via in vitro cell-based [13,[91][92][93] or preclinical animal model studies [94]. However, recently, some groups outside the USA have started clinical trials to analyze the efficacy of 3D printed BTE materials.…”

“…Furthermore, little attention has been paid to patientspecific implant architecture and mechanical function or to designing viable strategies that would restore site-specific function [11]. Patient-specific implants could be achieved through the use of computer-aided design (CAD) [12,13]. However, procedure-planning and implant-CAD software rarely include modeling of implant mechanical properties or the anticipated in vivo biomechanical load.…”