Bioprinting最新文献

The application of spheroids in tissue engineering has a number of advantages over conventional cell suspensions and 2D cultures. One of the methods for tissue and organ fabrication from spheroids is bioprinting. As one of bioprinting methods, laser-induced forward transfer (LIFT) has received much attention in terms of cell printing, while its potential has not been realized for spheroid patterning yet. In this paper, the authors have shown for the first time the practical applicability of LIFT for spheroid transfer with high survival rates and printing precision. For this, a special optical device, a piShaper, was used to change the laser energy distribution to non-Gaussian profile which allowed for mitigating the negative effects of laser radiation on the spheroids during LIFT. The authors showed that non-Gaussian energy distribution in the laser spot in the form of double ring led to higher post-printing viability of spheroids than in case of conventional Gaussian energy distribution in laser beam. Subsequently, using the double ring laser spot geometry, the spheroids were bioprinted in the form of simple geometric figures: line, triangle, and square. Overall, LIFT bioprinting of spheroids has demonstrated a strong potential as the precise, safe, and reproducible method for biofabrication that can be potentially used for making tissue-engineered bioequivalents or building specific organ-on-a-chip platforms.

Contamination of food and medical devices has become a serious public health concern. Therefore, this work intended to assess the single and combined antibacterial effect of essential oils (EOs) obtained from Clinopodium nepeta, Ruta montana, and Dittrichia viscosa, through mixture design approach. In addition, the anti-adhesive action of the obtained optimal mixtures of EOs was investigated against bacterial adhesion on 3D printed surface, widely used in food and medical industries. Indeed, Chromatography Gas/Mass spectrometry (CG/MS) analysis showed that pulegone (30.2%), piperitenone oxide (15.71%), and limonene (10.32%), mainly characterized the Clinopodium nepeta essential oil (CNEO), whereas Ruta montana essential oil (RMEO) was dominated by 2-undecanone (46.13%), and 2-nonanone (20.53%). By contrast, the Dittrichia viscosa essential oil (DVEO) principally contained (E)-nerolidol (32.21%), τ-muurolol (18.17%), and α-eudesmol (10.36%). The obtained optimum mixtures revealed that the binary combination consisting of 36% of RMEO, 64% of CNEO certified the maximal inhibition against Staphylococcus aureus (S. aureus), while a formulation of 25%, 50%, and 25% of RMEO, CNEO, and DVEO respectively, was associated to the ideal restriction of Pseudomonas aeruginosa (P. aeruginosa). The time-kill analysis showed that all studied EOs are able to eradicate the total growth (bactericidal action) of S. aureus and P. aeruginosa at twice-minimal inhibitory concentration (2xMIC) after 12 h. Interestingly, the contact angle method and environmental scanning electron microscopy (ESEM) analysis reported that the optimal EOs mixtures are effective in preventing biofilm formation by modification of physico-chemical parameters of the 3D printing resin surface and complete inhibition of bacterial adhesion on the material surface. Thereby, the interaction between EOs might be applied as natural preservatives in the food and medical industries.

Vascular grafts are used in numerous vascular surgeries around the world, although these procedures are constrained by vascular graft-related problems and size inconsistencies. This study developed and characterized vascular grafts using tissue engineering and 3D printing technology. To overcome vascular graft-related problems and size inconsistencies, this study developed a composite bio-ink using ECM of blood vessels, polyvinyl alcohol, and gelatin. Small-diameter vascular grafts were developed by Extrusion-based 3D printing and by molding techniques. The bioink was characterized in several aspects, followed by surface modification of a 3D vascular graft. The vascular grafts were evaluated for cytotoxicity and mechanical stability, which were found to be satisfactory. An in vivo biocompatibility and transplantation study showed cellular recruitment, elastin fibers, GAG as well as ECM (collagen) were retained. It was assessed by hematoxylin and eosin (H&E), alcian blue, and Masson's trichrome staining. Recellularization and well-structured ECM were seen in SEM images. In immunohistochemistry, positive vWF, α-SMA, and VEGF expression cells showed recruitment of endothelial and smooth muscle cells. In conclusion, tissue specific bio-ink shows promise for further translational research and clinical application.

Bone regenerative medicine requires suitable substitutes that promote osteogenesis. Most of the bio-macromolecular hydrogels are promising because they are biocompatible and biodegradable, but their viscoelastic properties make them challenging to use, especially in 3D bioprinting applications. This study aimed to enhance the mechanical properties of a bone substitute made of bioprinted alginate, carboxymethyl cellulose, and 58S bioglass. We used dual cross-linking and optimized the concentration of cross-linking agents to improve hydrogel biological activity and mechanical stability. The compression test indicated that the combination of Ca²⁺ and Fe³⁺ significantly improved the mechanical properties of the alginate/carboxymethyl cellulose hydrogel. The hydrogel crosslinked with 4% Ca²⁺ and 1.5% Fe³⁺ showed the highest Young's modulus. The study also found that the hydrogel rigidity influenced cell proliferation capability during bioprinting, as observed in the cell viability results. At day 7, the cell viability of the bioprinted constructs cross-linked with 0.5% and 1% Fe³⁺ exhibited significant increases. Similarly, these groups also demonstrated the highest alkaline phosphatase (ALP) activity at the same time. Results suggested that cross-linking density and resultant rigidity achieved by optimal concentrations of Fe³⁺ have very significant effects on cell viability and osteogenesis.

The use of bioabsorbable and biodegradable composites in the medical field has experienced significant growth. Cellulose nanofibers (CNF) have been employed to reinforce medical-grade poly[ε-caprolactone], enhancing both its load-bearing capacity and stiffness compared to pure polycaprolactone PCL. The manufacturing process involved a series of steps applied to five different grades of PCL/CNF filaments. Initially, melt extrusion and pelletization were performed on the filament, followed by 3D bioplotting to create the specimens. The influence of CNF reinforcement on poly[ε-caprolactone] was evaluated through a range of tests, including rheological, thermomechanical, and in situ micromechanical assessments. To further characterize the samples, Micro-Computed Tomography and Scanning Electron Microscopy fractography were employed for the microstructural and morphological analyses, respectively. The mechanical properties of poly[ε-caprolactone]/CNF composites with 6 wt % CNF content exhibited a 23.8% increase in tensile strength and a 19.1% increase in flexural strength compared to the pure matrix, while also displaying minimal porosity.

Three-dimensional (3D) bioprinting is a rapidly evolving technology with great potential for the fabrication of implantable and wearable devices. In this review, we provide a comprehensive overview of the current state-of-the-art methods in 3D bioprinting, including various printing techniques, materials, and applications. We explored the use of natural and synthetic polymers, hydrogels, and decellularized matrices in bioprinting, and discussed the development of implantable devices such as biosensors, drug delivery systems, and orthopaedic implants. We also discuss the challenges and opportunities associated with this technology, including optimizing bioprinting parameters and integrating printed devices with the host tissue. This review offers a broad perspective on the latest advancements in 3D bioprinting and provides insights into the future directions in this field.

The study proposes a platform for the formation and culture of non-small cell lung cancer (NSCLC) spheroids, to obtain an in vitro model suitable for drug and therapy testing. To achieve that, traditional cell culture is compared to methacrylated gelatin (GelMA) 3D bioprinting, in order to explore not only the potential of the matrix itself, but also the impact of different architectures on spheroid formation. Starting from a systematic analysis, where GelMA concentration, methacrylation degree and cell seeding concentration is set; three different architectures (round, ring and grid) are analyzed in terms of spheroid formation and growth, using 3D bioprinting. The study reveals that Very High GelMA 7.5% w/v formulation, with single cells dispersed in, is the best bioink to obtain NSCLC spheroids. Moreover, grid architecture performs in the best way, because of the highest volume-surface area ratio. The designed GelMA platform can be used as a powerful in vitro tool for drug testing and therapy screening, that can be designed playing with four different parameters: cell concentration, GelMA methacrylation degree, GelMA concentration and geometry.

The global prevalence of skin disease and injury is continually increasing, yet conventional cell-based models used to study these conditions do not accurately reflect the complexity of human skin. The lack of inadequate in vitro modeling has resulted in reliance on animal-based models to test pharmaceuticals, biomedical devices, and industrial and environmental toxins to address clinical needs. These in vivo models are monetarily and morally expensive and are poor predictors of human tissue responses and clinical trial outcomes. The onset of three-dimensional (3D) culture techniques, such as cell-embedded and decellularized approaches, has offered accessible in vitro alternatives, using innovative scaffolds to improve cell-based models' structural and histological authenticity. However, these models lack adequate organizational control and complexity, resulting in variations between structures and the exclusion of physiologically relevant vascular and immunological features. Recently, biofabrication strategies, which combine biology, engineering, and manufacturing capabilities, have emerged as instrumental tools to recreate the heterogeneity of human skin precisely. Bioprinting uses computer-aided design (CAD) to yield robust and reproducible skin prototypes with unprecedented control over tissue design and assembly. As the interdisciplinary nature of biofabrication grows, we look to the promise of next-generation biofabrication technologies, such as organ-on-a-chip (OOAC) and 4D modeling, to simulate human tissue behaviors more reliably for research, pharmaceutical, and regenerative medicine purposes. This review aims to discuss the barriers to developing clinically relevant skin models, describe the evolution of skin-inspired in vitro structures, analyze the current approaches to biofabricating 3D human skin mimetics, and define the opportunities and challenges in biofabricating skin tissue for preclinical and clinical uses.

3D bioprinting is an emerging technology for the fabrication of tissue constructs to repair damaged or diseased human tissues or as in vitro model systems for drug screening applications. Biomaterial-inks (polymeric hydrogel materials devoid of cells) or bio-inks (combination of polymeric hydrogel materials and cells) form the basis of 3D bioprinting. Successful 3D bioprinting requires optimisation of various process parameters such as biomaterial/bio inks’ viscoelastic, mechanical, and physiochemical properties which influence the printability. However, clinical translation of 3D bioprinted constructs requires that implantable devices are free of microbial contamination and further do not invoke microbial activity post implantation. Sterilization plays an important role in ensuring that inks are free of microorganisms. Recent investigations have shown that sterilization techniques directly influence the intrinsic properties of these inks, thereby affecting bioprinting process parameters. In this communication, we review the most common sterilization techniques that are used in the sterilization of biomaterial/bio inks and their effects on the inks’ properties such as viscoelasticity, mechanical, physiochemical and biological properties, and their influence on bioprinting parameters. To conclude, the available studies in the literature indicate that the sterilization processes influence the properties of biomaterial inks. Thus, the effect of sterilization methods on the materials’ properties needs to be thoroughly evaluated and reported while developing them for 3D bioprinting applications.

Fused filament fabrication (FFF) is a commonly used method for producing three-dimensional scaffolds using synthetic, degradable polymers. However, there are several variables that must be considered when fabricating devices for clinical use, one of which is storage conditions after printing. While the academic community has examined the impact of FFF on mechanical and thermal properties, there has been less focus on how storage conditions would affect the surface texture of scaffolds. Our hypothesis was that the surface, thermal and physical properties of FFF scaffolds are significantly influenced by the storage conditions. We evaluated the surfaces of FFF poly (ε-caprolactone) (PCL) and poly (ε-caprolactone-co-p-dioxanone) (PCLDX) strands that were stored at 4 °C, 20 °C, and 37 °C for 28 days. We monitored surface texture, physical and thermal changes to understand the effect of storage on the strands. The implementation of scale-sensitive fractal analysis and feature parameters revealed that storage conditions at 37 °C increased the number of hills and dales, as well as the density of peaks and pits compared to 20 °C and 4 °C, for both materials. The feature roughness parameters for PCL had up to 90% higher values than those of PCLDX, which correlated with the physical and thermal properties of the materials. These differences may impact further surface-cell interaction, highlighting the need for further evaluation for faster clinical translation. Our findings emphasize the importance of considering storage conditions in the design and manufacture of FFF scaffolds and suggest that the use of feature roughness parameters could facilitate the optimization and tailoring the surface properties for specific applications.