Due to its hardness, strength, and transparency, sapphire is an attractive material for the construction of microfluidic devices intended for high-pressure applications, but its physiochemical properties resist traditional microfabrication and bonding techniques. Here a femtosecond pulsed laser was used to directly machine fluidic channels within sapphire substrates and to form bonds between machined and flat sapphire windows, resulting in the creation of sealed microfluidic devices. Sapphire-sapphire bond strength was determined by destructive mechanical testing, and the integrity of the bond was verified by the capillary filling of the channel with air and ethanol.
View Article and Find Full Text PDFThere has been a pressing need for an expansion of the ventilator capacity in response to the recent COVID19 pandemic. To address this need, we present a system to enable rapid and efficacious splitting between two or more patients with varying lung compliances and tidal volume requirements. Reserved for dire situations, ventilator splitting is complex, and has been limited to patients with similar pulmonary compliances and tidal volume requirements.
View Article and Find Full Text PDFJ Mech Behav Biomed Mater
July 2020
The hierarchical and anisotropic mechanical behavior requirement of load-bearing soft tissues limits the utility of conventional elastomeric materials as a replacement for soft-tissue materials. Liquid-crystal elastomers (LCEs) have the potential to excel in this regard owing to its unique combination of mesogenic order in an elastomeric network. In this study, the mechanical behavior of the LCEs relevant to load-bearing biomedical applications was explored.
View Article and Find Full Text PDFHydrogels formed via free radical-mediated thiol-ene step-growth photopolymerization have been developed for a broad range of tissue engineering and regenerative medicine applications. While the crosslinking mechanism of thiol-ene hydrogels has been well-described, there has been only limited work exploring the physical differences among gels arising from variations in crosslinker properties. Here, we show that the character of linear polyethylene glycol (PEG) dithiols used to crosslink multi-arm polyethylene glycol norbornene (PEGNB) can be used as a facile strategy to tune hydrogel formation kinetics, and therefore the equilibrium hydrogel network architecture.
View Article and Find Full Text PDFAdvancements in the microfabrication of soft materials have enabled the creation of increasingly sophisticated functional synthetic tissue structures for a myriad of tissue engineering applications. A challenge facing the field is mimicking the complex microarchitecture necessary to recapitulate proper morphology and function of many endogenous tissue constructs. This paper describes the creation of PEGDA hydrogel microenvironments (microgels) that maintain a high level of viability at single cell patterning scales and can be integrated into composite scaffolds with tunable modulus.
View Article and Find Full Text PDFIEEE Trans Nanobioscience
April 2019
Controlled cell delivery has shown some promising outcomes compared with traditional cell delivery approaches over the past decades, and strategies focused on optimization or engineering of controlled cell delivery have been intensively studied. In this paper, we demonstrate the fabrication of a 3D printed hydrogel scaffold infused with degradable PEGPLA/NB composite hydrogel core for controlled cell delivery with improved cell viability and facile tunability. The 3D printed poly (ethylene glycol) diacrylate (PEGDA) scaffold with specifically designed architectures can provide mechanical support while allowing bidirectional diffusion of small molecules, thus permitting structural integrity and long-term cell viability.
View Article and Find Full Text PDFArthropod Struct Dev
September 2013
Variation in the morphology of the insect tracheal system can strongly affect respiratory physiology, with implications for everything from pest control to evolution of insect body size. However, the small size of most insects has made measuring the morphology of their tracheal systems difficult. Historical approaches including light microscopy and scanning and transmission electron microscopy (SEM, TEM) are technically difficult, labor intensive, and can introduce preparation artifacts.
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