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International Journal of Bioprinting 3D printing in gastroenterology

Table 4. 3D printing of decellularized scaffolds
Author Year Animal Printed object Application Printing machine Printing Printing technique Seeded cells Extracellular Bioreactor Results
model material matrix
Park et al. [75] 2016 Rabbit Artificial esophageal patch Repairment of partial esophageal 3D Bioplotter PCL Extrusion Rabbit MSCs Fibrin, thrombin None Better cell regeneration in MSC group
defect
Chung et al. [76] 2018 Rat Tubular scaffold Repairment of transectional BT-3000 PCL 3D printing & None None Omentum Better cell regeneration in MSC group
esophageal defect electrospinning
Kim et al. [77] 2019 Rat Esophageal graft Repairment of transectional 3D Bioplotter PCL/PU 3D printing & Human MSCs None Custom-made & omentum Satisfactory tissue regeneration with both
esophageal defect electrospinning bioreactors
Boyer et al. [95] 2019 In vitro Biliary stent Biliary procedures MakerBot PVA N/A Human PMSCs, human Collagen Growth medium Satisfactory cholangiocytes coating
Replicator primary cholangiocytes
Fouladian et al. [81] 2020 In vitro Esophageal stent Malignant esophageal stenosis Ultimaker S5 PU+5-FU FDM None None None Sustained release of 5-FU over 110 days
Ha et al. [79] 2021 Rat Esophageal stent Treating radiation esophagitis 2RPS PCL Extrusion None EdECM-based None Rapid resolution of inflammatory response
hydrogel
Kim et al. [80] 2021 Rat Artificial esophageal patch Repairment of partial esophageal Simplify 3D v. 4.0 PCL+TCN Extrusion None None None Better tissue regeneration and antibacterial
defect activity
Park et al. [78] 2021 Rat Artificial esophageal patch Repairment of partial esophageal 3D Bioplotter PCL/PU 3D printing & ADSC Matrigel & Growth medium Better cell regeneration in ADSC group
defect electrospinning fibronectin

Abbreviations: ADSC, adipose-derived mesenchymal stem cell; EdECM, esophagus-derived decellularized extracellular matrix; FDM, fused deposition
modeling; 5-FU, 5-fluorouracil; MSCs, mesenchymal stem cells; PMSCs, placental mesenchymal stem cells; PCL, polycaprolactone; PU, polyurethane;
PVA, polyvinyl alcohol; TCN, tetracycline.

that make a subjective evaluation of improvement of skills expect the cells to self-assemble to form a native histological
and patient satisfaction more credible (e.g., structured structure. Should 3D bioprinted grafts be applied to the
scoring systems); and (iii) an adequate sample size that human gastroenterological system, several questions must
meets statistical principles. be answered first: (i) What kind of cells are needed and where

When it comes to 3D printing, several limitations, such do we get them? (ii) What kind of bioink best stimulates cell
as high expenses, long printing time, change in size, and low growth and differentiation? (iii) Is the bioink formulation a
printing resolution, hinder its widespread patient-specific panacea or tissue-specific? (iv) Does the printing technology
application. Printing technology and materials need further and material support a 1:1 duplicate of native human organ
refinement to achieve time-effective and cost-effective or tissue with mechanical, microbiological, immunological,
results while producing high-resolution [104] , durable, and and neurological functions as well as microenvironments of
biocompatible models and objects. Implantable objects blood and lymphatic vessels, and how fast can it be? (v) Is
also have to endure sterile procedures and challenging 3D-printed organoid transplantation an alternative to organ
physical or chemical environments in vivo. Researchers or tissue transplantation, and for what kind of scenarios
may also consider printing GI models with lifelike textures might it be suitable?
and histological layers (e.g., mucosa and submucosa) to In the end, machine learning (ML) has been popular
provide better simulative effects. Another question for in the last decades, and several attempts have been made
models concerning surgery and patient education is that in process optimization, defect detection, dimensional
who should cover the printing cost. accuracy analysis, bioink design, and cellular viability
prediction [105-108] . While many challenges remain, how
To better meet the clinical demands of organ replacement,
reconstruction, and repair, either cell-seeded scaffolds or artificial intelligence might be integrated into tissue design,
bioink formulation, cell sorting and culture, printing, and
bioprinted scaffolds have to acquire physiological properties monitoring in gastroenterology is still an interesting task
such as secretion, absorption, and peristalsis that resemble in the future.
native tissues. While researchers have realized some of
those properties, such as in the regenerations of multilayer 7. Conclusion
epithelium and smooth muscle, they were mostly performed
on mice, rats, or rabbits. Such experiments have not been Although much seems to have been tried, gastroenterology
conducted in larger mammals. Whether the scaffolds can is still a less developed area for 3D printing and bioprinting.
be immediately transplanted or they should be left in a However, it is promising for vast clinical requirements.
bioreactor after bioprinting remains to be explored. We Preoperative planning, realistic simulation, evaluation

Volume 9 Issue 6 (2023) 163 https://doi.org/10.36922/ijb.0149