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Zhang, et al.
developed . In this manufacturing system, light 3 Medical devices
[21]
is reflected onto the photosensitive material in the
form of a 2D image. When different plane images A medical device is an important tool that can benefit
are projected onto the material from different the patient by helping health-care providers diagnose
angles, the energy generated by the multi-angle and treat patients, assisting patients to overcome
superposition exposure will cause the material to sickness or disease, and improving their quality of
[25]
converge into the originally designed 3D structure. life . The 3D printing technology has been widely
This technology can be scaled up to a relatively applied in fabricating specific medical devices based
large additive manufacturing volume and is order on patients’ disease. According to the statistics, the
of magnitude faster than conventional 3D printing U.S. Food and Drug Administration (FDA) has
methods. approved at least 85 3D printed medical devices up to
[26]
To design products with ideal performance, the 2015 . These products including medical models,
selection of appropriate materials has become an personalized implants, and functionalized devices.
important requirement. Materials for DLP printing 3.1 Medical models
are photosensitive polymers that can polymerize
from liquid into solid when exposed to light. The The solid 3D model can remedy the limitation
physical and chemical properties of traditional of medical imaging technology that can only
photosensitive polymers limit their applications. transform the information of patients’ lesions into
Most of them are incompatible with cells. What is visual graphics and display them to doctors and
more, the monomers and its vapors are also harmful patients. These 3D models are tangible objects that
to humans. Hence, researchers have manifolded can be operated by hand and can directly reflect
the materials used for DLP-based 3D printing. Due patients’ conditions, providing more intuitive and
to the biocompatibility and good polymerization convenient means for clinical medical teaching,
effect, PEGDA and GelMA are widely used inks diagnosis, and surgical planning. The 3D printing
for bioprinting. Soon et al. modified silk fibroin technology provides a method that can use the
with glycidyl methacrylate to get SF-based bioink- graphic information to create patient‐specific
methyl acrylate (SiL-MA). This polymerized anatomical 3D medical models . So far, a series
[27]
SiL-MA hydrogel has the characteristics of high of medical models have been manufactured by
tensile strength, which is available to suture. In various 3D printing technologies, such as skull,
addition, SiL-MA hydrogels produced by DLP heart, pelvis, blood vessel, and tumor, which are
3D printing have remarkable biocompatibility, beneficial to surgery assistance, disease analysis,
which gives the hydrogel a broad application and teaching demonstration [28,29] .
prospect in the field of tissue engineering . Many Due to the fast printing speed of DLP‐based 3D
[22]
components can be mixed in the liquid printed printing, doctors no longer have to wait for long
materials to obtain functionalized constructs. The hours to prepare 3D models of patients’ pathological
addition of piezoelectric BaTiO nanoparticles organs. In the clinical treatment of various acute
3
and electric silver nanoparticles to ink can give diseases, such as cerebral hemorrhage, cerebral
the products the functions of piezoelectricity and infarction, and myocardial infarction, the effective
electroconductibility, respectively. Ceramic and treatment window period is only a few hours,
glass products can be sintered with printing inks requiring the doctor to prepare the patient’s surgical
combining ceramic fillers or silicate [23,24] . These plan within a few minutes. On the premise of
improvements made this manufacturing method ensuring printing accuracy (~100 μm), polymeric
more competitive in fabricating medical products. models, up to tens of centimeters, in size can be
Given the favorable properties of printing produced in minutes . This characteristic can
[20]
speed, accuracy, and materials, DLP 3D printing meet the time requirement of clinical treatments
has great value in the rapid fabrication of precision of the above acute disease models. Compared
personalized products. with other 3D printing technologies, the DLP

International Journal of Bioprinting (2020)–Volume 6, Issue 1 15