Lithography-based additive manufacture of ceramic biodevices with design-controlled surface topographies

Abstract

The possibility of manufacturing textured materials and devices, with surface properties controlled from the design stage, instead of being the result of machining processes or chemical attacks, is a key factor for the incorporation of advanced functionalities to a wide set of micro-and nanosystems. High-precision additive manufacturing (AM) technologies based on photopolymerization, together with the use of fractal models linked to computer-aided design tools, allow for a precise definition of final surface properties. However, the polymeric master parts obtained with most commercial systems are usually inadequate for biomedical purposes and their limited strength and size prevents many potential applications. On the other hand, additive manufacturing technologies aimed at the production of final parts, normally based on layer-by-layer melting or sintering ceramic or metallic powders, do not always provide the required precision for obtaining controlled micro-structured surfaces with high-aspect-ratio details. Towards the desired degree of precision and performance, lithography-based ceramic manufacture is a remarkable option, as we discuss in the present study, which presents the development of two different micro-textured biodevices for cell culture. Results show a remarkable control of the surface topography of ceramic parts and the possibility of obtaining design-controlled micro-structured surfaces with high-aspect-ratio micro-metric details.

Monolithic 3D labs- and organs-on-chips obtained by lithography-based ceramic manufacture

“…This corresponds, from measured taken with the help of CAD software, to an original volume of 1.75 cm 3 for the whole microsystem and to a final volume of 1.45 cm 3 , which corresponds to a global volume variation of a 18%, which is in accordance with the theoretical results for obtaining a relative density of around 99% after elimination of the polymeric phase and sintering. In general terms, this is in line with previous studies by our team [9], although in this case a slight difference in the contraction along the z axis (3.3%) can be appreciated, when compared with the contractions along x and y axes (with a mean contraction of 7.15%). This may be a consequence of liquid polymerization shrinkage during the additive process, which affects in a larger degree in the directions perpendicular to the construction, as the sintering process is expected to be more isotropic.…”

“…The complete microsystem can be circumscribed by a box of 30 × 30 × 3 mm 3 (X, Y, Z, directions respectively). According to the detailed dimensions and to previous experiences [2,9,15,16], lithography-based manufacture constitutes a very adequate micro-manufacturing technology for the development of the proposed biomedical microsystem in an additive way and using ceramic materials. The materials used in the process have also proved excellent for in vitro trials with cells [9].…”

“…Some interesting and recent applications of these additive manufacturing technologies have been linked to the development of new concepts of cell culture systems [7] and of complex geometrical microfluidic systems [8], normally resorting to selective laser sintering/melting for a final metallic device, although polymeric, ceramic and composite powders can be also three-dimensionally sintered. New trends also describe the use of additive processes for obtaining design-controlled surface roughness and, hence, optimizing cell-material interactions [9].…”

Stereolithography

“…Variations of the thermal treatment include implementing an additional drying step prior to debinding to remove solvents or combining debinding and sintering into one single but correspondingly longer thermal process to eliminate potential defect sources during transportation of the fragile brown parts [59].…”

Effect of UV Radiation by Projectors on 3D Printing

“…For obtaining of micro-structured surfaces with high precision, additional ceramic or metallic powders may be used. These additives serve for reaching of better mechanical properties of the model [5]. A lot of different methods in this area were designed and experimentally approved by TU Wien.…”