# Additive Manufacturing and Chemical Engineering: Looking for Synergies from a Bibliometric Study
## 4 Review of Research Focused on Additive Manufacturing and Chemical Engineering
### Additive Manufacturing and Biofabrication
#### 4.1.3 Bioprinting Applications
To fully leverage these models in high-throughput drug discovery, systematic validations and standardizations are necessary to ensure their potential effectiveness [69]. A widespread biological component in many organ-on-chip devices is an engineered vascular interface since it is present in almost all organs of the human body. The vasculature and the vascular interface function as the conduits for inter-cellular and inter-organ interactions and regulate drug transport, being particularly susceptible to biomechanical forces. Chemical engineering has contributed with different approaches applied to modeling human vasculature with an emphasis on the engineering of organ-specific vasculatures [101]. Additionally, chemical engineering research has proven its capacity to enhance organs-on-chip and improve the production processes. On the one hand, a conductive ink including poly-(3_A_-ethylene-dioxythiophene)-polystyrene sulfonate microparticles doped in polyethylene glycol diacrylate was developed to integrate tunable hydrogel electrodes into bioprinted organs-on-chips [102]. The prepared electrodes successfully induced electrical stimulation to control cell orientations, morphology, and gene expressions when encapsulated in gelatin methacryloyl, resulting in higher cellular activities, cell densities, and spheroid sizes. On the other hand, many current organs-on-a-chip devices are produced via handcrafted processes, which require the expertise and abilities of skilled operators. Automated and scalable fabrication methods are preferred to generate these devices, and recent research efforts are focused on this objective. A high-throughput heart-on-a-chip platform incorporating fluorescent nanocomposite microwires as force sensors produced from quantum dots and thermoplastic elastomer and 3D printed on top of a polystyrene tissue culture base patterned by hot embossing has been developed [103]. The increased fabrication efficiency allowed the availability of numerous units of these ease-of-use systems to gauge drug responses in matured cardiac tissue. The combination of additive manufacturing, scanning, and imaging techniques offers a new paradigm for medical treatment, providing faster, more economical, and efficient solutions that alter the traditional supply chain of the medical industry. For example, the adoption of additive manufacturing enables the mass production of precise anatomical models that can be used by orthopedic surgeons for surgical planning purposes. Additive manufacturing allows the production of implants with complex internal geometries and structures, as well as custom medical implants that meet specific individual needs based on patients' computed tomography scans and magnetic resonance images, making them highly promising for clinical applications [104]. Tools, instruments, and parts for medical devices that enhance a clinical operation can also be obtained by additive manufacturing and external medical guide supports, such as long-term postoperative supports, external prostheses, prosthesis sockets, motion guides, fixators, personalized splints, and other orthopedic complements (Figure 12) [105]. Research by chemical engineers has been relevant for the identification of optimal materials and additive manufacturing technologies for the production of anatomical models. For example, different materials across a broad range of 3D printing technologies were evaluated to identify the combination that most precisely represents the parietal region of the skull for burr hole simulation [106]. The study found that 3D-printed polyethylene terephthalate glycol (using fused filament fabrication) and White Resin (using stereolithography) were the best models to replicate the skull. Even the main safety aspects of the drilling of these anatomical models were evaluated by measuring the presence of airborne particles and volatile organic compounds [107].