Journal: Science Advances

Article Title: Thermofluidic heat exchangers for actuation of transcription in artificial tissues

doi: 10.1126/sciadv.abb9062

Figure Lengend Snippet: ( A ) Schematic of thermofluidic workflow. A biocompatible fluid flows around a power supplied heating element to preheat the fluid before entry in perfusable channel networks within hydrogel tissue constructs laden with heat-sensitive cells. During perfusive heating, hydrogel temperature is continuously monitored using an infrared camera. ( B ) Perfusable channel networks of varying spatial geometries can be bioprinted within biocompatible 3D hydrogels. Top: 3D rendering of network architectures. Middle: Hydrogel channels infused with tonic water fluoresce when imaged under ultraviolet backlight. Bottom: Infrared thermography of heat-perfused hydrogels demonstrates that during perfusion, heat traces the path of fluid flow and dissipates into the bulk hydrogel. Scale bars, 5 mm.

Article Snippet: To establish a fluidic connection between the heating system and hydrogel channel networks, we used custom-designed 3D printed perfusion chips printed on a MakerGear M2 3D printer (MakerGear, Beachwood, OH) in consumer-grade poly(lactic acid) plastic filament.

Techniques: Construct

Journal: Science Advances

Article Title: Thermofluidic heat exchangers for actuation of transcription in artificial tissues

doi: 10.1126/sciadv.abb9062

Figure Lengend Snippet: ( A ) HEK293T cells were engineered to express fLuc under the HSPA6 promoter. ( B ) Schematic of thermofluidic activation of encapsulated cells. ( C ) Single-channel tissue used for 3D heat activation (left). Scale bar, 3 mm. Transmittance image of cellularized hydrogel after printing (middle). Scale bar, 500 μm. HEK293T cells in bioprinted tissues stained with calcein-AM (“live,” green) and ethidium homodimer (“dead,” red; right). Scale bars, 200 μm. ( D ) Representative infrared images of thermofluidic perfusion in single-channel hydrogels. Scale bars, 2 mm. ( E ) Hydrogel temperatures are tuned by changing heater power at constant flow rate ( n = 3, mean temperature ± standard error). ( F ) Representative bioluminescence images of hydrogels (top; scale bars, 2 mm) and intensity traces at three positions (A to C) across the width ( x ) of the hydrogel after 30 min of perfused heating. ( G ) Fold change in bioluminescence after 30 min of heating relative to 25°C controls. ( H ) Representative bioluminescence images of hydrogels (top; scale bars, 2 mm) and intensity traces after 60 min of perfused heating (bottom; scale bars, 2 mm). ( I ) Fold change in bioluminescence after 60 min of heating demonstrates a temperature-dependent dosage response in gene expression [(G and I); n = 3, mean fold luminescence ± standard error; * P < 0.05 and ** P < 0.01 by one-way ANOVA followed by Dunnett’s multiple comparison test]. ( J ) Temperature-expression response curve (black) shows mean bioluminescent radiance across temperature; shaded regions (gray) indicate ± SD. n = 3. Photo credit: Daniel Corbett, University of Washington.

Article Snippet: To establish a fluidic connection between the heating system and hydrogel channel networks, we used custom-designed 3D printed perfusion chips printed on a MakerGear M2 3D printer (MakerGear, Beachwood, OH) in consumer-grade poly(lactic acid) plastic filament.

Techniques: Activation Assay, Staining, Expressing