Open-Source Selective Laser Sintering (OpenSLS) of Nylon and Biocompatible Polycaprolactone.

Ian S Kinstlinger,Samantha J Paulsen,Andreas Bastian,Tim Schmidt,Anderson H Ta,Jordan S Miller,David R Yalacki,Daniel H Hwang,David T Eddington

doi:10.1371/journal.pone.0147399

Abstract

Selective Laser Sintering (SLS) is an additive manufacturing process that uses a laser to fuse powdered starting materials into solid 3D structures. Despite the potential for fabrication of complex, high-resolution structures with SLS using diverse starting materials (including biomaterials), prohibitive costs of commercial SLS systems have hindered the wide adoption of this technology in the scientific community. Here, we developed a low-cost, open-source SLS system (OpenSLS) and demonstrated its capacity to fabricate structures in nylon with sub-millimeter features and overhanging regions. Subsequently, we demonstrated fabrication of polycaprolactone (PCL) into macroporous structures such as a diamond lattice. Widespread interest in using PCL for bone tissue engineering suggests that PCL lattices are relevant model scaffold geometries for engineering bone. SLS of materials with large powder grain size (~500 μm) leads to part surfaces with high roughness, so we further introduced a simple vapor-smoothing technique to reduce the surface roughness of sintered PCL structures which further improves their elastic modulus and yield stress. Vapor-smoothed PCL can also be used for sacrificial templating of perfusable fluidic networks within orthogonal materials such as poly(dimethylsiloxane) silicone. Finally, we demonstrated that human mesenchymal stem cells were able to adhere, survive, and differentiate down an osteogenic lineage on sintered and smoothed PCL surfaces, suggesting that OpenSLS has the potential to produce PCL scaffolds useful for cell studies. OpenSLS provides the scientific community with an accessible platform for the study of laser sintering and the fabrication of complex geometries in diverse materials.

Highlights

The advent of additive manufacturing (AM) technology, referred to as 3D printing (3DP), has led to its increased use in industry and scientific laboratories, as well as in homes and community makerspaces [1,2]
We believe that open-source SLS system (OpenSLS) could serve the scientific community as an accessible platform for fabrication of structures composed of a wide range of materials, including those not supported by commercial Selective Laser Sintering (SLS) suppliers or their maintenance contracts
The lack of affordable laser sintering technology for a laboratory setting motivated the construction of an inexpensive open-source Selective Laser Sintering (OpenSLS) system repurposed from a commercial laser cutter

Summary

Introduction

The advent of additive manufacturing (AM) technology, referred to as 3D printing (3DP), has led to its increased use in industry and scientific laboratories, as well as in homes and community makerspaces [1,2]. Selective Laser Sintering (SLS) is a third and highly versatile AM process that creates solid parts by tracing a laser beam, focused onto a thin layer of powder, in a 2D pattern [20]. We address the production of highly intricate scalable models of physiologic structures, the fabrication of fluidic networks derived from sintered parts, and the implementation of SLS for cell studies aimed at biomaterials science and tissue engineering. We present these diverse applications together to highlight the multifaceted impact that access to low-cost, customizable SLS technology could have on scientific research in various disciplines. OpenSLS represents a meaningful addition to the growing body of open-source technologies that give engineers and scientists access to and unprecedented control over advanced fabrication and analytical tools at low cost

Materials and Methods

Results and Discussion

Conclusions