Printability in 3D extrusion bioprinting encompasses extrudability, filament formation, and shape fidelity. Rheological properties can predict the shape fidelity of printed hydrogels. In particular, tan(δ), the ratio between loss (G'') and storage (G') modulus (G''/G'), is a powerful indicator of printability. This study explores the effect of different salt, sucrose, and MC concentrations on tan(δ), and therefore the printability of methylcellulose (MC) hydrogels. Salt and sucrose increased G', lowering tan(δ) and enabling printing of scaffolds with high shape fidelity. Conversely, MC concentration increased G'' and G', having a lesser effect on tan(δ). Shape fidelity of three formulations with similar G' but varying tan(δ) values were compared. Higher tan(δ) led to reduced height, while lower tan(δ) improved shape fidelity. Cell viability increased when reducing MC content, extrusion rate, and nozzle gauge. Higher MC concentration (G' > 1.5 kPa) increased the influence of needle size and extrusion rate on cell viability. Hydrogels with G' < 1 kPa could be extruded at high rates with small nozzles, minimally affecting cell viability. This work shows a direct relationship between tan(δ) and printability of MC-based hydrogels. Lowering the complex modulus of hydrogels, mitigates extrusion stress, thus improving cell survival.
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http://dx.doi.org/10.1016/j.ijbiomac.2023.127461 | DOI Listing |
Biofabrication
January 2025
Division of Engineering, New York University Abu Dhabi, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates, Abu Dhabi, 129188, UNITED ARAB EMIRATES.
Corneal blindness, a leading cause of visual impairment globally, has created a pressing need for alternatives to corneal transplantation due to the severe shortage of donor tissues. In this study, we present a novel interpenetrating network hydrogel composed of gelatin methacryloyl (GelMA) and oxidized carboxymethyl cellulose (OxiCMC) for bioprinting a biomimetic corneal stroma equivalent. We tested different combinations of GelMA and OxiCMC to optimize printability and subsequently evaluated these combinations using rheological studies for gelation and other physical, chemical, and biological properties.
View Article and Find Full Text PDFWe present the first, to our knowledge, metasurface holographic display method with exceptional fidelity and minimal edge noise, based on highly uniform flat-top light generated by a digital micromirror device (DMD). Based on the error-diffusion algorithm and iterative refinement process, the amplitude distribution of the initial Gaussian light was dynamically closed-loop modulated, and the standard difference of the intensity of the 3 mm diameter center flat-top beam was reduced to less than 3.4%.
View Article and Find Full Text PDFHealth Res Policy Syst
January 2025
University College London, London, United Kingdom.
Background: The deteriorating mental health of children and young people in the United Kingdom poses a challenge that services and policy makers have found difficult to tackle. Kailo responds to this issue with a community-based participatory and systemically informed strategy, perceiving mental health and well-being as a dynamic state shaped by the interplay of broader health determinants. The initiative works to explore, define and implement locally relevant solutions to challenges shaping the mental health and well-being of young people.
View Article and Find Full Text PDFBats are reservoir hosts for numerous well-known zoonotic viruses, but their broader virus-hosting capacities remain understudied. are an order of enteric viruses known to cause disease across a wide range of mammalian hosts, including Hepatitis A in humans and foot-and-mouth disease in ungulates. Host-switching and recombination drive the diversification of worldwide.
View Article and Find Full Text PDFPilot Feasibility Stud
January 2025
CIDEFES Centro de Investigação em Educação Física, Desporto, Exercício e Saúde, Universidade Lusófona, Lisbon, Portugal.
Background: Despite the benefits of physical activity (PA), cancer survivors report engagement barriers, and existing interventions often lack comprehensive solutions. Theory-based interventions using evidence-based behavior change techniques (BCTs) have been shown to be effective in promoting PA for breast cancer survivors, although their feasibility and acceptability lack evidence. The PAC-WOMAN trial is a three-arm randomized controlled trial aimed at promoting short- and long-term PA and improving the quality of life of breast cancer survivors.
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