Project description:Solid State Fermentation (SSF) processes have been explored for yeast growth and protein and metabolites production. However, most of these processes lack standardization. In this work, we present a polylactic acid (PLA) 3D printed matrix that dramatically enhances yeast growth when embedded in liquid media compared to equivalent static cultures, and changes yeast expression patterns at the proteome level. Moreover, differences in sugar assimilation and ethanol production, as the main product of alcoholic fermentation, are observed. Our results suggest that these matrixes may be useful for a vast range of biotechnological applications based on yeast fermentation.
Project description:Solid State Fermentation (SSF) processes have been explored for yeast growth and protein and metabolites production. However, most of these processes lack standardization. In this work, we present a polylactic acid (PLA) 3D printed matrix that dramatically enhances yeast growth when embedded in liquid media compared to equivalent static cultures, and changes yeast expression patterns at the proteome level (data are available via ProteomeXchange with identifier PXD043759). Moreover, differences in sugar assimilation and ethanol production, as the main product of alcoholic fermentation, are observed. Our results suggest that these matrixes may be useful for a vast range of biotechnological applications based on yeast fermentation.
Project description:Chronic wounds in diabetic patients are challenging because their prolonged inflammation makes healing difficult, thus burdening patients, society, and health care systems. Customized dressing materials are needed to effectively treat such wounds that vary in shape and depth. The continuous development of 3D-printing technology along with artificial intelligence has increased the precision, versatility, and compatibility of various materials, thus providing the considerable potential to meet the abovementioned needs. Herein, functional 3D-printing inks comprising DNA from salmon sperm and DNA-induced biosilica inspired by marine sponges, are developed for the machine learning-based 3D-printing of wound dressings. The DNA and biomineralized silica are incorporated into hydrogel inks in a fast, facile manner. The 3D-printed wound dressing thus generates provided appropriate porosity, characterized by effective exudate and blood absorption at wound sites, and mechanical tunability indicated by good shape fidelity and printability during optimized 3D printing. Moreover, the DNA and biomineralized silica act as nanotherapeutics, enhancing the biological activity of the dressings in terms of reactive oxygen species scavenging, angiogenesis, and anti-inflammation activity, thereby accelerating acute and diabetic wound healing. These bioinspired 3D-printed hydrogels produce using a DNA-induced biomineralization strategy are an excellent functional platform for clinical applications in acute and chronic wound repair.
Project description:Accelerating the rate of polyester hydrolytic degradation is of interest for numerous biomedical applications. Poly(ε-caprolactone) (PCL) and poly(L-lactic acid) (PLLA) have been extensively studied as thermoplastic homo- and copolymers as well as PCL-PLLA blends. PCL-PLLA semi-interpenetrating networks (semi-IPN) prepared with thermoplastic PLLA embedded in a cross-linked PCL diacrylate (PCL-DA) network were previously shown to exhibit uniquely accelerated degradation behavior that increased with PLLA content. Herein, their properties before and during degradation were further investigated to reveal the origin of this behavior and to better understand the semi-IPNs' degradation mechanism. Initially, semi-IPNs exhibited restricted spherulite size and irregularity, as well as a phase-separated morphology and PLLA-rich surface. Under accelerated conditions (1 M NaOH, 37 °C), degradation was revealed to be initiated in PLLA regions. It was also found that the PCL-DA crosslinking and PCL-PLLA phase separation played the largest roles in degradation rates and that semi-IPNs underwent faster rates of degradation than an analogous blend largely due to the reduced crystallinity of PCL-DA. Non-accelerated conditions (PBS [pH = 7.4], 37 °C) up to 56 weeks, which had never before been studied for polyester semi-IPNs, revealed similar trends in degradation rates.
Project description:Several inflammatory conditions of the bile ducts cause strictures that prevent the drainage of bile into the gastrointestinal tract. Non-pharmacological treatments to re-establish bile flow include plastic or self-expanding metal stents (SEMs) that are inserted in the bile ducts during endoscopic retrograde cholangiopancreatography (ERCP) procedures. The focus of this study was to 3D print an anatomically accurate model of the extrahepatic bile ducts (EHBDs) with tissue-like mechanical properties to improve in vitro testing of stent prototypes. Following generation of an EHBD model via computer aided design (CAD), we tested the ability of Formlabs SLA 3D printers to precisely print the model with polymers selected based on the desired mechanical properties. We found the printers were reliable in printing the dimensionally accurate EHBD model with candidate polymers. Next, we evaluated the mechanical properties of Formlabs Elastic (FE), Flexible (FF), and Durable (FD) resins pre- and post-exposure to water, saline, or bile acid solution at 37 °C for up to one week. FE possessed the most bile duct-like mechanical properties based on its elastic moduli, percent elongations at break, and changes in mass under all liquid exposure conditions. EHBD models printed in FE sustained no functional damage during biliary stent deployment or when tube connectors were inserted, and provided a high level of visualization of deployed stents. These results demonstrate that our 3D printed EHBD model facilitates more realistic pre-clinical in vitro testing of biliary stent prototypes.
Project description:3D biomaterial manufacturing strategies show an extraordinary driving force for the development of innovative therapies in the tissue engineering field. Here, the behaviour of 3D printed chitosan (CH)-based scaffolds was explored as a function of the post-printing gelation process. To this purpose, gel forming properties of different media were tested on their capability to retain 3D structure, water content, mechanical resistance and surface/internal porosity. Three different gelation media (i.e. KOH 1.5 M, Na2CO3 1.5 M, ammonia vapours) were selected and the 3D CH scaffolds were tested in terms of biocompatibility toward fibroblast as skin associated human cell line.
Project description:Polyethylene (PE), one of the most popular thermoplastic polymers, is widely used in various areas, such as materials engineering and biomedical engineering, due to its superior performance, while 3D printing via fused deposition modeling (FDM) provides a facile method of preparing PE products. To optimize the performance and assess the degradation of FDM-printed PE materials, we systematically investigate the influences of printing parameters, such as fiber diameter (stretching) and printer head temperature, and degradation, such as UV exposure and thermal degradation, on the mechanical performance of FDM-printed PE fibers. When FDM-printed PE fibers with a smaller diameter are prepared under a higher collecting speed, they undergo stronger stretching, and thus, show higher tensile strength and Young's modulus values. Meanwhile, the tensile strength and Young's modulus decrease as the printer head temperature increases, due to the lower viscosity, and thus, weaker shearing at high temperatures. However, degradation, such as UV exposure and thermal degradation, cause a decrease in all four mechanical properties, including tensile strength, Young's modulus, tensile strain and toughness. These results will guide the optimization of FDM-printed PE materials and help to assess the durability of PE products against degradation for their practical application.
Project description:Fused deposition modeling (FDM), the most widely used additive manufacturing (AM) technology, is gaining considerable interest in the surgical sector for the production of single-use surgical devices that can be tailor-made according to specific requirements (e.g., type of patient surgery, specific shapes, etc.) due to its low cost, ease of access to materials (3D-printing filament), and the relatively low complexity. However, surgical 3D-printing parts should resist sterilization treatments without losing structural, mechanical, and dimensional accuracy. Thus, in this work, 3D-filaments based on poly(lactic acid) (PLA), poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG), and a modified PETG material (CPE) were used to produce 3D-printed parts and further subjected to moist heat (MH) and dry heat (DH) sterilization processes as affordable and widely used sterilization processes in the medical field. The effect of MH and DH was evaluated by performing a complete mechanical, structural, thermal, and morphological characterization before and after both treatments. In general, the moist heat treatment produced a higher degradation of the polymeric matrix of PETG and CPE due to hydrolytic and thermal degradation, particularly affecting the tensile test and flexural properties. For instance, the linear coefficient of thermal expansion (LCTE) before glass transition temperature (Tg) increased 47% and 31% in PETG samples due to the MH and DH, respectively, while it increased 31% in CPE due to MH and was mainly maintained after the DH process. Nevertheless, in PLA, the MH produced an increase of 20% in LCTE value and the DH showed an increase of 33%. Dry heat treatment resulted in being more suitable for medical applications in which dimensional accuracy is not a key factor and there are no great mechanical demands (e.g., surgical guides).
Project description:Biomechanical testing of soft tissues forms the backbone in the experimental validation of tissue engineering and for modelling purposes. The standardized testing of soft tissues requires different experimental protocols and fixtures compared to hard tissues or non-biological materials due to their characteristics. Some of the most commonly-used clamping methods for soft tissue testing affect the tissues' mechanical properties as chemicals are involved to decelerate degradation and autolysis. Moreover, they are unsuitable for standardized and high-throughput testing. Material slippage is also a recurrent unwanted influence on the testing routine with impact on measurement validity. Addressing these issues, this protocol presents a clamping system for simplified testing of biological soft tissues with all necessary components manufactured utilizing 3D printing technology. Templates allow trimming the samples into standardized shapes and sizes while preparation tables facilitate clamping in a fixed distance. The key parts of the system are clamps with a pyramid design, which allow the mounting of biological soft tissues before transferring it into the testing device and minimize material slippage during tensile testing. Flexible holder arms are used to transfer samples from preparation tables into the testing device and simplify positioning. Mechanical testing itself is performed with digital image correlation for precise strain measurements.
Project description:The advancement of microgravity simulators is helping many researchers better understanding the impact of the mechanically unloaded space environment on cellular function and disfunction. However, performing microgravity experiments on Earth, using simulators such as the Random Positioning Machine, introduces some unique practical challenges, including air bubble formation and leakage of growth medium from tissue culture flask and plates, all of which limit research progress. Here, we developed an easy-to-use hybrid biological platform designed with the precision of 3D printing technologies combined with PDMS microfluidic fabrication processes to facilitate reliable and reproducible microgravity cellular experiments. The system has been characterized for applications in the contest of brain cancer research by exposing glioblastoma and endothelial cells to 24 h of simulated microgravity condition to investigate the triggered mechanosensing pathways involved in cellular adaptation to the new environment. The platform demonstrated compatibility with different biological assays, i.e., proliferation, viability, morphology, protein expression and imaging of molecular structures, showing advantages over the conventional usage of culture flask. Our results indicated that both cell types are susceptible when the gravitational vector is disrupted, confirming the impact that microgravity has on both cancer and healthy cells functionality. In particular, we observed deactivation of Yap-1 molecule in glioblastoma cells and the remodeling of VE-Cadherin junctional protein in endothelial cells. The study provides support for the application of the proposed biological platform for advancing space mechanobiology research, also highlighting perspectives and strategies for developing next generation of brain cancer molecular therapies, including targeted drug delivery strategies.