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International Journal of Bioprinting 3D bioprinting for lung tissue

expansion of functional lung tissue production, enhancing of artificial lung tissues or lung organs at the macroscale,
vascularization approaches, and ensuring sustained precise tissue compositions at the microscale, and even cell
long-term functionality [1,2] . Conditions such as chronic and molecular compositions at the nanoscale. Although
obstructive pulmonary disease (COPD), pulmonary extensive work has been done on the 3D bioprinting
fibrosis, and lung cancer pose significant challenges to for LTE, there, to the best of our knowledge, appears no
global health, severely impacting patients’ quality of life review paper in this field. In this review, we present a
and overall prognosis [3,4] . LTE is of paramount importance comprehensive overview of the principles and recent
in the context of lung diseases, as it holds great potential advancements in 3D bioprinting for LTE. We proceed
for revolutionizing innovative strategies to replace or to explore crucial elements such as the composition
repair damaged lung tissue by leveraging the principles of of bioink and the printing methodologies employed,
biology, materials science, and engineering . The ultimate and explore the potential of multiscale bioprinting to
[5]
goal is to provide effective treatments and potential cures faithfully reproduce the intricate architecture of the lung,
for regenerative medicine (RM), offering new possibilities ranging from macrostructures to nanoscale features.
for patients requiring respiratory interventions. Especially, Furthermore, we emphasized the current progress and
LTE combined with three-dimensional (3D) bioprinting future perspectives in the in vitro reconstitution of lung
holds great promise for advancing our understanding of tissue, covering crucial considerations like cell sourcing,
lung diseases, developing new therapies, and potentially functionalization, and integration of physiological cues.
providing transplantable lung tissue in the future. With these groundbreaking techniques, a new era is
Bioprinting, as defined by the American Society for dawning in the realm of lung tissue development, opening
Testing Materials (ASTM), is a specific method used doors to functional and biologically accurate constructs.
to 3D-print biomaterials into various structures. 3D This remarkable progress promises to revolutionize disease
bioprinting is a specific technique used within the broader modeling, drug screening, and RM for lung conditions.
field of tissue engineering (TE), to precisely deposit 2. Material inks for lung tissue fabrication
cells, biomaterials, and growth factors in a 3D manner
to create complex structures [6,7] . The common strategies As the native extracellular matrix (ECM) can offer
of 3D bioprinting include inkjet-based bioprinting, structural support to tissues, it is important to find an
extrusion-based bioprinting, and laser-assisted (e.g., engineered ECM that can serve the same purpose. Material
stereolithography) bioprinting (Figure 1) . Over the past inks play a crucial role in TE as they provide scaffolds for
[8]
few decades, the field of 3D bioprinting has experienced cell growth and differentiation, facilitating the formation
significant advancements in terms of the types of tissue of functional tissues . In the context of lung fabrication,
[21]
models that can be constructed, including cancer , blood several biomaterials are being explored for creating lung
[9]
vessels [10,11] , heart , and lungs [13,14] . Indeed, 3D bioprinting tissue in vitro. For example, hydrogels (including alginate,
[12]
has the potential to offer various benefits and applications collagen, gelatin, and fibrin) are water-based materials
beyond just lung transplantation. 3D bioprinting allows that can mimic pulmonary ECM . They provide a 3D
[18]
the creation of patient-specific tissues and organs, tailored environment for cells to grow and can be engineered to
to individual needs. Additionally, researchers can create have specific mechanical properties and biochemical
disease-specific models using bioprinting, allowing cues. Additionally, biocompatible and biodegradable
them to study the effects of drugs on specific tissues or synthetic polymers like poly(lactic-co-glycolic acid)
organs without endangering patients [9,15,16] . Although this (PLGA), polycaprolactone (PCL), and polyethylene glycol
technology is still in its early stages, researchers have made (PEG) are commonly used in 3D printing or melded into
progress in generating small, simplified organs like liver the scaffolds. In addition, decellularized ECM (dECM)
patches, kidney tissues, and more . Therefore, the ability of encompasses the characteristics of an ideal tissue scaffold:
[17]
3D bioplotting to recreate the lung tissue allows researchers complex composition, vascular networks, and unique
to investigate disease progression, cellular interactions, tissue-specific architecture [22,23] . Therefore, dECM has
and responses to different drugs or treatments . 3D emerged as a potential biomaterial ink with tissue-specific
[18]
bioprinting has emerged as a transformative tool that composition for LTE . During the fabrication process,
[24]
enables the creation of intricate 3D structures across microcarrier inks, which are small, spherical particles,
different scales, ranging from macroscale to microscale play a role in carrying and protecting cells. Furthermore,
and even nanoscale. the incorporation of nanofibers and nanoparticles can
enhance the mechanical properties and surface area
Considering the complex structure and dynamic
characteristics of lung, researchers have made various of the nanoscale lung scaffolds. To achieve lung-like
structures with appropriate architecture and functionality,
summaries [19,20] . 3D bioprinting enables the construction

Volume 9 Issue 6 (2023) 437 https://doi.org/10.36922/ijb.1166