Biofabrication PDF

1. Kareyl Tuesday, 3 December 2024 4:37 pm Harnessing the Regenerative Potential of Fetal Mesenchymal Stem Cells and Endothelial Colony-Forming Cells in the Biofabrication of Tissue-Engineered Vascular Grafts (TEVGs) ABSTRACT: 1. Tissue engineering is a promising approach for the production o...

1. Kareyl Tuesday, 3 December 2024 4:37 pm Harnessing the Regenerative Potential of Fetal Mesenchymal Stem Cells and Endothelial Colony-Forming Cells in the Biofabrication of Tissue-Engineered Vascular Grafts (TEVGs) ABSTRACT: 1. Tissue engineering is a promising approach for the production of small-diameter vascular grafts; however, there are limited data directly comparing the suitability of applicable cell types for vessel biofabrication. 2. Here, we investigated the potential of adult smooth muscle cells (SMCs), placental mesenchymal stem cells (MSCs), placental endothelial colony-forming cells (ECFCs), and a combination of MSCs and ECFCs on highly porous biocompatible poly(ε-caprolactone) (PCL) scaffolds produced via melt electro-writing (MEW) for the biofabrication of tissue-engineered vascular grafts (TEVGs). 3. Cellular attachment, proliferation, and deposition of essential extracellular matrix (ECM) components were analyzed in vitro over four weeks. 4. TEVGs cultured with MSCs accumulated the highest levels of collagenous components within a dense ECM, while SMCs and the coculture were more sparsely populated, ascertained via histological and immunofluorescence imaging, and biochemical assessment. 5. Scanning electron microscopy (SEM) enabled visualization of morphological differences in cell attachment and growth, with MSCs and SMCs inflating and covering scaffolds completely within the 28-day culture period. 6. Coverage and matrix deposition by ECFCs was limited. However, ECFCs lined the ECM formed by MSCs in coculture, visualized via immunostaining. Thus, of cells investigated, placental MSCs were identified as the preferred cell source for the fabrication of tissue-engineered constructs, exhibiting an extensive population of porous polymer scaffolds and production of ECM components; with the inclusion of ECFCs for luminal endothelialization, an encouraging outcome warranting further consideration in future studies. 7. In combination, these findings represent a substantial step toward the development of the next generation of small-diameter vascular grafts in the management of cardiovascular disease. CONCLUSIONS: 1. TEVGs cultured with MSCs exhibited enhanced DNA, GAG, and collagen accumulation, in combination with substantial tissue growth. Biofabrication Page 1 2. Mike Tuesday, 3 December 2024 4:38 pm 3D Bioprinting of Diatom-Laden Living Materials for Water Quality Assessment ABSTRACT: 1. Diatoms have long been used as living biological indicators for the Assessment of water quality in lakes and rivers worldwide. While this approach benefits from the great diversity of these unicellular algae, Established protocols are time-consuming and require specialized equipment. 2. Here, this work 3D prints diatom-laden hydrogels that can be used as a simple multiplex bio- indicator for water assessment. The hydrogel-based living materials are created with the help of a desktop extrusion-based printer using a suspension of diatoms, cellulose nanocrystals (CNC), and alginate as bio-ink constituents. 3. Rheology and mechanical tests are employed to establish optimum bio-ink formulations, whereas cell culture experiments are utilized to evaluate the proliferation of the entrapped diatoms in the presence of selected water contaminants. 4. Bioprinting of diatom-laden hydrogels is shown to be an enticing approach to generating living materials that can serve as low-cost bio-indicators for water quality assessment. CONCLUSION: 1. The hydrogel inks used as feedstock require an optimum concentration of cellulose nanocrystals, sodium alginate, and calcium ions. 2. Increasing conc. of cellulose nanocrystals and Ca ions favor bioprinting of distortion-free geometry but a lower diatom growth rate. 3. Bioindicators successfully produced to assess the presence of NaCl, herbicide, and anti- microbial agent in water by evaluating diatom proliferation after 2 weeks. 4. Cell proliferation quantified using color and auto-fluorescence of chlorophyll pigments by optical microscopy and direct visualization. Biofabrication Page 2 3. Cerilo Tuesday, 3 December 2024 4:38 pm Green Biofabrication of Silver Nanoparticles of Potential Synergistic Activity with Antibacterial and Antifungal Agents against Some Nosocomial Pathogens ABSTRACT: 1. Nosocomial bacterial and fungal infections are one of the main causes of high morbidity and mortality worldwide, owing to the high prevalence of multidrug-resistant microbial strains. Hence, the study aims to synthesize, characterize, and investigate the antifungal and antibacterial activity of silver nanoparticles (AgNPs) fabricated using Camellia sinensis leaves against nosocomial pathogens. 2. The biogenic AgNPs revealed a small particle diameter of 35.761+/- 3.18 nm based on transmission electron microscope (TEM) graphs and a negative surface charge of 14.1 mV, revealing the repulsive forces between nanoparticles, which in turn indicated their colloidal stability. 3. The disk diffusion assay confirmed that Escherichia coli was the most susceptible bacterial strain to the biogenic AgNPs (200 g/disk), while the lowest sensitive strain was found to be the Acinetobacter baumannii strain with relative inhibition zones of 36.14 0.67 and 21.04 0.19 mm, respectively. 4. On the other hand, the biogenic AgNPs (200 g/disk) exposed antifungal efficacy against Candida albicans strain with a relative inhibition zone of 18.16 0.14 mm in diameter. The biogenic AgNPs exposed synergistic activity with both tigecycline and clotrimazole against A. baumannii and C. albicans, respectively. 5. In conclusion, the biogenic AgNPs demonstrated distinct physicochemical properties and potential synergistic bioactivity with tigecycline, linezolid, and clotrimazole against gram- negative, gram positive, and fungal strains, respectively. This is paving the way for the development of effective antimicrobial combinations for the effective management of nosocomial pathogens in intensive care units (ICUs) and health care settings. Biofabrication Page 3 4. Arnimi Tuesday, 3 December 2024 4:38 pm Biofabrication of Prevascularized Spheroids for Bone Tissue Engineering by Fusion of Microvascular Fragments with Osteoblasts ABSTRACT: Introduction: Spheroids are promising building blocks for scaffold-free bone tissue engineering. Their rapid vascularization is of major importance to guarantee their survival after transplantation. To achieve this, we herein introduce the biofabrication of prevascularized spheroids by fusion of adipose tissue-derived microvascular fragments (MVF) with osteoblasts (OB). Methods: For this purpose, 200 MVF from donor mice and 5,000, 10,000 or 20,000 murine OB (MC3T3-E1) were co-cultured in a liquid overlay system for 3 days to generate OB + MVF spheroids. OB mono-culture spheroids served as controls. Results and discussion: During the generation process, the diameters of all spheroids progressively decreased, resulting in compact, viable spheroids of homogeneous sizes. MVF promoted the maturation of spheroids containing 5,000 OB, as shown by an accelerated decline of cell proliferation due to contact inhibition. Moreover, MVF is most effectively reassembled into new microvascular networks within these small spheroids when compared to the other spheroid types, indicating the most beneficial MVF to OB ratio. Accordingly, these spheroids also showed a high angiogenic sprouting activity in vitro. In contrast to OB spheroids, they further rapidly vascularized in vivo after transplantation into dorsal skinfold chambers. This was caused by the interconnection of incorporated MVF with surrounding blood vessels. These findings indicate that OB + MVF spheroids may be suitable for bone tissue engineering, which should be next tested in appropriate in vivo bone defect models Biofabrication Page 4 5. Franz Tuesday, 3 December 2024 4:38 pm Rapidly Degrading Hydrogels to Support Biofabrication and 3D Bioprinting Using Cartilage Microtissues ABSTRACT: 1. In recent years, there has been increased interest in the use of cellular spheroids, microtissues, and organoids as biological building blocks to engineer functional tissues and organs. Such microtissues are typically formed by the self-assembly of cellular aggregates and the subsequent deposition of a tissue-specific extracellular matrix (ECM). Biofabrication and 3D bioprinting strategies using microtissues may require the development of supporting hydrogels and bioinks to spatially localize such biological building blocks in 3D space and hence enable the engineering of geometrically defined tissues. 2. Therefore, the aim of this work was to engineer scaled-up, geometrically defined cartilage grafts by combining multiple cartilage microtissues within a rapidly degrading oxidized alginate (OA) supporting hydrogel and maintaining these constructs in dynamic culture conditions. To this end, cartilage microtissues were first independently matured for either 2 or 4 days and then combined in the presence or absence of a supporting OA hydrogel. 3. Over 6 weeks in static culture, constructs engineered using microtissues that were matured independently for 2 days generated higher amounts of glycosaminoglycans (GAGs) compared to those matured for 4 days. 4. Histological analysis revealed intense staining for GAGs and negative staining for calcium deposits in constructs generated by using the supporting OA hydrogel. Less physical contraction was also observed in constructs generated in the presence of the supporting gel; however, the remnants of individual microtissues were more observable, suggesting that even the presence of a rapidly degrading hydrogel may delay the fusion and/or there modeling of the individual microtissues. 5. Dynamic culture conditions were found to modulate ECM synthesis following the OA hydrogel encapsulation. 6. We also assessed the feasibility of 3D bioprinting of cartilage microtissues within OA based bioinks. It was observed that the microtissues remained viable after extrusion-based bioprinting and were able to fuse after 48h, particularly when high microtissue densities were used, ultimately generating a cartilage tissue that was rich in GAGs and negative for calcium deposits. 7. Therefore, this work supports the use of OA as a supporting hydrogel/bioink when using microtissues as biological building blocks in diverse biofabrication and 3D bioprinting platforms. Biofabrication Page 5 6. Elaine Tuesday, 3 December 2024 4:38 pm Plant seed-inspired Cell Protection, Dormancy, and Growth for Large-Scale Biofabrication ABSTRACT: 1. Biofabrication technologies have endowed us with the capability to fabricate complex biological constructs. However, cytotoxic biofabrication conditions have been a major challenge for their clinical application, leading to a trade-off between cell viability and scalability of biofabricated constructs. 2. Taking inspiration from nature, we proposed a cell protection strategy that mimicks the protected and dormant state of plant seeds in adverse external conditions and their germination in response to appropriate environmental cues. 3. Applying this bioinspired strategy to biofabrication, we successfully preserved cell viability and enhanced the seeding of cell-laden biofabricated constructs via a cytoprotective pyrogallol (PG)-alginate encapsulation system. Our cytoprotective encapsulation technology utilizes PG-triggered sporulation and germination processes to preserve cells and is mechanically robust, chemically resistant, and highly customizable to adequately match cell protectability with the cytotoxicity of biofabrication conditions. 4. More importantly, the facile and tunable decapsulation of our PG-alginate system allows for the effective germination of dormant cells, under typical culture conditions. With this approach, we have successfully achieved a biofabrication process that is reproducible, and scalable, and provided a practical solution for off-the-shelf availability, shipping, and temporary storage of fabricated bio-constructs. Biofabrication Page 6