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A methodology to develop a vascular geometry for in vitro cell culture using additive manufacturing
prevent it from being marketable on a large scale. However, • Optimization of the product with iterations
the disadvantages of PDMS are the absorption of small • Final validation
molecules, the manufacturing method incompatible with • Make sure the product is correctly used
mass production and also its reversible hydrophilicity. • Tests prototype and medical return to improve the
Lachaux et al. found a new polymer (Flexdym) offering model.
flexibility and translucent comparable to PDMS. Flexdym Thus, in this article, an innovative methodology
is a copolymer block solution, composed of Di or Triblock to achieve a complex vascular geometry using AM
according to the different grade. It is similarities with the is proposed. As mentioned before, there are few
PDMS but without the drawbacks. Easy and inexpensive methodologies that combine the realization of medical
microstructuration method, microfluidic devices are devices and AM processes. Existing methodologies do
fabricated in less than a minute . not propose to simplify the complex geometry to allow
[21]
Furthermore, microfabrication can be performed faster validation of all subsequent steps such as the choice
using a hot-embossing machine or a very simple press of material or the cellular study. Here, we can proceed
equipment; downstream Flexdym is amenable for rapid with iteration loops and improve our design each time
manufacturing technology such as injection molding. to finally fulfill the complex form. Thus, the proposed
Flexdym can be bonded easily without surface treatments method can be adapted to any case study.
and pressure loads, thanks to is mechanical properties.
Sealing can be achieved either on a simple hot plate or 4. A Methodology to Develop Vascular
even at room temperature. It is flexible and thus allows Geometry for In Vitro Cell Culture using
cutting into small pieces. It is translucent and biocompatible AM: AM-Biopart
which will allow the study of cell culture. Due to its
bonding qualities, two-part molding is envisaged. The proposed method (Figure 5) is based on important
Recently, cell culture studies have been released on points told in the synthesis that chosen from the existing
VeroClear, AM material. Lu et al. used Veroclear because methods seen previously.
of its good formation properties and high precision. The method proposed by Lenoir et al. (2019) is
However, the interactions between cells and materials divided into four steps. The first “Initialization” consists
are affected by topography and surface chemistry of the of understanding and summarizing the objectives, needs,
implant materials, such as roughness and hydrophilic and constraints desired by the medical profession.
properties . Knowledge is capitalized and well transferred between
[22]
In this study, authors have developed a method engineers and health professionals.
of coating waterborne polyurethane (WPU) onto the Then, Step II, “concept and feasibility” allow to search
Veroclear resin to improve the biocompatibility. WPU and define the different manufacturing methods and then
(Safe polymeric material) is a coating material for to know their costs.
creating barriers between corrosive environments and For Step III, “design and development” is more
material surfaces. WPU has been used in medical implants complex. Geometry simplification strategy is included
because of its low toxicity, good biocompatibility, and (Step III, 1) to allow engineers to focus first on the
coating characteristics. material to be used that meets the different constraints.
Once these parameters have been approved (Step III, 8),
3.4. Synthesis the geometry can be made more complex (Step III, 9).
Only a few papers rely on AM to produce biomedical Then, the whole process can start again (Steps III, 2) to
parts. This paper highlights existing methodologies for (Steps III, 7), through an improvement of the design, until
designing innovative products based on AM, others that the final validation of the realistic 3D model.
can help develop innovative medical devices. However, it Finally, during the last step, the design is optimized
is difficult to find a methodology that combines these two by performing user tests. At the end, once everything is
aspects; there are only a few at the intersection of these validated and optimized, only training for clinical use
two technologies. remains.
The interesting points of these different methodologies 5. Use Case AM-Biopart Adapted to the
are: Manufacturing of a Carotid
• Well understand the goals and needs of the user
• Engineers and health professionals pool their In this section, the method is tested on the manufacturing
knowledge throughout the project of a carotid (Figure 6) in vitro to understand the
• Strategic choice and plan of manufacturing before physiopathology.
prototyping This carotid was modeled by ARM (Figure 7), on
• Design by performing user tests a sickle cell child. ARM is an exam that specifically

104 International Journal of Bioprinting (2019)–Volume 5, Issue 2