bims-biprem Biomed News
on Bioprinting for regenerative medicine
Issue of 2024–04–07
six papers selected by
Seerat Maqsood, University of Teramo



  1. Biofabrication. 2024 Apr 03.
      Regenerative healing of spinal cord injury poses an ongoing medical challenge by causing persistent neurological impairment and a significant socioeconomic burden. The complexity of spinal cord tissue presents hurdles to successful regeneration following injury, due to the difficulty of forming a biomimetic structure that faithfully replicates native tissue using conventional tissue engineering scaffolds. 3D bioprinting is a rapidly evolving technology with unmatched potential to create 3D biological tissues with complicated and hierarchical structure and composition. With the addition of biological additives such as cells and biomolecules, 3D bioprinting can fabricate preclinical implants, tissue or organ-like constructs, and in vitro models through precise control over the deposition of biomaterials and other building blocks. This review highlights the characteristics and advantages of 3D bioprinting for scaffold fabrication to enable spinal cord injury repair, including bottom-up manufacturing, mechanical customization, and spatial heterogeneity. This review also critically discusses the impact of various fabrication parameters on the efficacy of spinal cord repair using 3D bioprinted scaffolds, including the choice of printing method, scaffold shape, biomaterials, and biological supplements such as cells and growth factors. High-quality preclinical studies are required to accelerate the translation of 3D bioprinting into clinical practice for spinal cord repair. Meanwhile, other technological advances will continue to improve the regenerative capability of bioprinted scaffolds, such as the incorporation of nanoscale biological particles and the development of 4D printing.
    Keywords:  biomaterials; bioprinting; spinal cord injury; stem cells; tissue engineering
    DOI:  https://doi.org/10.1088/1758-5090/ad3a13
  2. Biofabrication. 2024 Apr 03.
      With the advent of personalized medicine, the drug delivery system (DDS) will be changed significantly. The development of personalized medicine needs the support of many technologies, among which three-dimensional printing (3DP) technology is a novel formulation-preparing process that creates 3D objects by depositing printing materials layer-by-layer based on the computer-aided design (CAD) method. Compared with traditional pharmaceutical processes, 3DP produces complex drug combinations, personalized dosage, and flexible shape and structure of dosage forms (DFs) on demand. In the future, personalized 3DP drugs may supplement and even replace their traditional counterpart. We systematically introduce the applications of 3DP technologies in the pharmaceutical industry and summarize the virtues and shortcomings of each technique. The release behaviors and control mechanisms of the pharmaceutical DFs with desired structures are also analyzed. Finally, the benefits, challenges, and prospects of 3DP technology to the pharmaceutical industry are discussed.
    Keywords:  3D printing; Dosage form; Personalized medicine; Precise drug delivery
    DOI:  https://doi.org/10.1088/1758-5090/ad3a14
  3. Adv Mater. 2024 Apr 05. e2402301
      4D (bio-)printing endows 3D printed (bio-)materials with multiple functionalities and dynamic properties. 4D printed materials have been recently used in biomedical engineering for the design and fabrication of biomedical devices, such as stents, occluders, micro-needles, smart 3D-cell engineered micro-environments, drug delivery systems, wound closures, and implantable medical devices. However, the success of 4D printing relies on the rational design of 4D printed objects, the selection of smart materials, and the availability of appropriate types of external (multi-)stimuli. Here, we first highlight the different types of smart materials, external stimuli, and design strategies used in 4D (bio-)printing. Then, we present a critical review of the biomedical applications of 4D printing and discuss the future directions of biomedical research in this exciting area, including In vivo tissue regeneration studies, the implementation of multiple materials with reversible shape memory behaviors, the creation of fast shape-transformation responses, the ability to operate at the microscale, untethered activation and control, and the application of (machine learning-based) modeling approaches to predict the structure-property and design-shape transformation relationships of 4D (bio)printed constructs. This article is protected by copyright. All rights reserved.
    Keywords:  4D printing; biomaterials; biomedical engineering; bioprinting; smart materials
    DOI:  https://doi.org/10.1002/adma.202402301
  4. Expert Opin Drug Deliv. 2024 Mar 30. 1-13
       BACKGROUND: Pain is characterized as a major symptom induced by tissue damage occurring from surgical procedures, whose potency is being experienced subjectively, while current pain relief strategies are not always efficient in providing individualized treatment. 3D printed implantable devices hold the potential to offer a precise and customized medicinal approach, targeting both tissue engineering and drug delivery.
    RESEARCH DESIGN AND METHODS: Polycaprolactone (PCL) and PCL - chitosan (CS) composite scaffolds loaded with procaine (PRC) were fabricated by bioprinting. Geometrical features including dimensions, pattern, and infill of the scaffolds were mathematically optimized and digitally determined, aiming at developing structurally uniform 3D printed models. Printability studies based on thermal imaging of the bioprinting system were performed, and physicochemical, surface, and mechanical attributes of the extruded scaffolds were evaluated. The release rate of PRC was examined at different time intervals up to 1 week.
    RESULTS: Physicochemical stability and mechanical integrity of the scaffolds were studied, while in vitro drug release studies revealed that CS contributes to the sustained release dynamic of PRC.
    CONCLUSIONS: The printing extrusion process was capable of developing implantable devices for a local and sustained delivery of PRC as a 7-day adjuvant regimen in post-operative pain management.
    Keywords:  3D printing; biopolymers; chitosan; drug delivery systems; implantable scaffolds; polycaprolactone; printability; thermal imaging
    DOI:  https://doi.org/10.1080/17425247.2024.2336492
  5. J Biomech Eng. 2024 Apr 01. 1-36
      Development of respiratory tissue constructs is challenging due to the complex structure of native respiratory tissue and the unique biomechanical conditions induced by breathing. While studies have shown that the inclusion of biomechanical stimulus mimicking physiological conditions greatly benefits the development of engineered tissues, to our knowledge no studies investigating the influence of biomechanical stimulus on the development of respiratory tissue models produced through three-dimensional (3D) bioprinting have been reported. This paper presents a study on the utilization of a novel breath-mimicking ventilated incubator to impart biomechanical stimulus during the culture of 3D respiratory bioprinted. Constructs were bioprinted using an alginate/collagen hydrogel containing human primary pulmonary fibroblasts with further seeding of human primary bronchial epithelial cells. Biomechanical stimulus was then applied via a novel ventilated incubator capable of mimicking the pressure and airflow conditions of multiple breathing conditions: standard incubation, shallow breathing, normal breathing and heavy breathing, over a two-week time period. At time points between 1-14 days, constructs were characterized in terms of mechanical properties, cell proliferation and morphology. The results illustrated that incubation conditions mimicking normal and heavy breathing led to greater and more continuous cell proliferation and further indicated a more physiologically relevant respiratory tissue model.
    DOI:  https://doi.org/10.1115/1.4065214
  6. Mater Today Bio. 2024 Jun;26 100991
       Background: Effective communication is crucial for broad acceptance and applicability of alternative methods in 3R biomedical research and preclinical testing. 3D bioprinting is used to construct intricate biological structures towards functional liver models, specifically engineered for deployment as alternative models in drug screening, toxicological investigations, and tissue engineering. Despite a growing number of reviews in this emerging field, a comprehensive study, systematically assessing practices and reporting quality for bioprinted liver models is missing.
    Methods: In this systematic scoping review we systematically searched MEDLINE (Ovid), EMBASE (Ovid) and BioRxiv for studies published prior to June 2nd, 2022. We extracted data on methodological conduct, applied bioinks, the composition of the printed model, performed experiments and model applications. Records were screened for eligibility and data were extracted from included articles by two independent reviewers from a panel of seven domain experts specializing in bioprinting and liver biology. We used RAYYAN for the screening process and SyRF for data extraction. We used R for data analysis, and R and Graphpad PRISM for visualization.
    Results: Through our systematic database search we identified 1042 records, from which 63 met the eligibility criteria for inclusion in this systematic scoping review. Our findings revealed that extrusion-based printing, in conjunction with bioinks composed of natural components, emerged as the predominant printing technique in the bioprinting of liver models. Notably, the HepG2 hepatoma cell line was the most frequently employed liver cell type, despite acknowledged limitations. Furthermore, 51% of the printed models featured co-cultures with non-parenchymal cells to enhance their complexity. The included studies offered a variety of techniques for characterizing these liver models, with their primary application predominantly focused on toxicity testing. Among the frequently analyzed liver markers, albumin and urea stood out. Additionally, Cytochrome P450 (CYP) isoforms, primarily CYP3A and CYP1A, were assessed, and select studies employed nuclear receptor agonists to induce CYP activity.
    Conclusion: Our systematic scoping review offers an evidence-based overview and evaluation of the current state of research on bioprinted liver models, representing a promising and innovative technology for creating alternative organ models. We conducted a thorough examination of both the methodological and technical facets of model development and scrutinized the reporting quality within the realm of bioprinted liver models. This systematic scoping review can serve as a valuable template for systematically evaluating the progress of organ model development in various other domains. The transparently derived evidence presented here can provide essential support to the research community, facilitating the adaptation of technological advancements, the establishment of standards, and the enhancement of model robustness. This is particularly crucial as we work toward the long-term objective of establishing new approach methods as reliable alternatives to animal testing, with extensive and versatile applications.
    Keywords:  3D bioprinting; 3R; Bioink; HepG2; Hepatocytes; Xeno-free
    DOI:  https://doi.org/10.1016/j.mtbio.2024.100991