Tissue Engineering for Gastrointestinal and Genitourinary Tracts

Semi-automated layer-by-layer biofabrication using rotational internal flow layer engineering technology

The automation of biofabrication processes has the potential to increase both the scale and reproducibility of human tissue production for replacing animal usage in research and ultimately clinical use. The biofabrication technology, Rotational Internal Flow Layer Engineering (RIFLE), produces layered tubular constructs with a resolution commensurate with the microscale strata observed in many human tissue types. The previously published RIFLE process required liquid phase cell-laden hydrogels to be manually applied onto the inner surface of a high-speed rotating mould. Here we describe improvement of the RIFLE system by automating elements of the process, in particular the liquid dispensing element, and present the use of this system for two commonly used biofabrication hydrogels; alginate and collagen. Semi-automatically assembled cell layers matched the viabilities of those produced manually, with automated collagen demonstrating the highest viabilities (>91 %) over the 10 days measured, highlighting its advantages as a material for tissue engineering applications. The encapsulation of labelled cells in predefined collagen layer patterns confirmed that the semi-automated RIFLE system was able to assemble separate cell populations in cell-width layers (≈14 µ m). Semi-automated dosing reduced the manual operations in the RIFLE process, reducing the workload on researchers and minimising the opportunity for human error. Further opportunity exists for higher levels of automation in the overall process, particularly needed in the preparation of cell-hydrogel suspensions, a common manual labour-intensive process in many biofabrication technologies.

Biomimetic tubular materials: from native tissues to a unifying view of new vascular, tracheal, gastrointestinal, oesophageal, and urinary grafts

Repairing tubular tissues-the trachea, the esophagus, urinary and gastrointestinal tracts, and the circulatory system-from trauma or severe pathologies that require resection, calls for new, more effective graft materials. Currently, the relatively narrow family of materials available for these applications relies on synthetic polymers that fail to reproduce the biological and physical cues found in native tissues. Mimicking the structure and the composition of native tubular tissues to elaborate functional grafts is expected to outperform the materials currently in use, but remains one of the most challenging goals in the field of biomaterials. Despite their apparent diversity, tubular tissues share extensive compositional and structural features. Here, we assess the current state of the art through a dual layer model, reducing each tissue to an inner epithelial layer and an outer muscular layer. Based on this model, we examine the current strategies developed to mimic each layer and we underline how each fabrication method stands in providing a biomimetic material for future clinical translation. The analysis provided here, addressed to materials chemists, biomaterials engineers and clinical staff alike, sets new guidelines to foster the elaboration of new biomimetic materials for effective tubular tissue repair.

Recent advances in artificial intelligent strategies for tissue engineering and regenerative medicine

BACKGROUND

Tissue engineering and regenerative medicine (TERM) aim to repair or replace damaged or lost tissues or organs due to accidents, diseases, or aging, by applying different sciences. For this purpose, an essential part of TERM is the designing, manufacturing, and evaluating of scaffolds, cells, tissues, and organs. Artificial intelligence (AI) or the intelligence of machines or software can be effective in all areas where computers play a role.

METHODS

The "artificial intelligence," "machine learning," "tissue engineering," "clinical evaluation," and "scaffold" keywords used for searching in various databases and articles published from 2000 to 2024 were evaluated.

RESULTS

The combination of tissue engineering and AI has created a new generation of technological advancement in the biomedical industry. Experience in TERM has been refined using advanced design and manufacturing techniques. Advances in AI, particularly deep learning, offer an opportunity to improve scientific understanding and clinical outcomes in TERM.

CONCLUSION

The findings of this research show the high potential of AI, machine learning, and robots in the selection, design, and fabrication of scaffolds, cells, tissues, or organs, and their analysis, characterization, and evaluation after their implantation. AI can be a tool to accelerate the introduction of tissue engineering products to the bedside.

HIGHLIGHTS

The capabilities of artificial intelligence (AI) can be used in different ways in all the different stages of TERM and not only solve the existing limitations, but also accelerate the processes, increase efficiency and precision, reduce costs, and complications after transplantation. ML predicts which technologies have the most efficient and easiest path to enter the market and clinic. The use of AI along with these imaging techniques can lead to the improvement of diagnostic information, the reduction of operator errors when reading images, and the improvement of image analysis (such as classification, localization, regression, and segmentation).

A perioperative layered autologous tissue expansion graft for hollow organ repair

Tissue engineering has not been widely adopted in clinical settings for several reasons, including technical challenges, high costs, and regulatory complexity. Here, we introduce the Perioperative Layered Autologous Tissue Expansion graft (PLATE graft), a composite biomaterial and collagen-reinforced construct with autologous epithelium on one side and smooth muscle tissue on the other. Designed to mimic the structure and function of natural hollow organs, the PLATE graft is unique in that it can be produced in a standard operating theatre and is cost-effective. In this proof-of-principle study, we test its regenerative performance in eight different organs, present biomechanical and permeability tests, and finally explore its in vivo performance in live rabbits.

Extracellular Matrix-Based and Electrospun Scaffolding Systems for Vaginal Reconstruction

Congenital vaginal anomalies and pelvic organ prolapse affect different age groups of women and both have significant negative impacts on patients' psychological well-being and quality of life. While surgical and non-surgical treatments are available for vaginal defects, their efficacy is limited, and they often result in long-term complications. Therefore, alternative treatment options are urgently needed. Fortunately, tissue-engineered scaffolds are promising new treatment modalities that provide an extracellular matrix (ECM)-like environment for vaginal cells to adhere, secrete ECM, and be remodeled by host cells. To this end, ECM-based scaffolds or the constructs that resemble ECM, generated by self-assembly, decellularization, or electrospinning techniques, have gained attention from both clinicians and researchers. These biomimetic scaffolds are highly similar to the native vaginal ECM and have great potential for clinical translation. This review article aims to discuss recent applications, challenges, and future perspectives of these scaffolds in vaginal reconstruction or repair strategies.