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Image patterned molecular delivery into live cells using gold particle coated substrates.

Wu TH, Kalim S, Callahan C, Teitell MA, Chiou PY - Opt Express (2010)

Bottom Line: An image-patterned molecular delivery system for mammalian cells is demonstrated by pulsed laser irradiation of gold particles immobilized on a substrate below a cell monolayer.Patterned cavitation bubble nucleation was captured using a time-resolved imaging system and molecular delivery verified by observing the uptake of a membrane-impermeable fluorescent dye, calcein.Delivery efficiency as high as 90% was observed and multiplexed, patterned dye delivery was demonstrated.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, University of California, Los Angeles (UCLA), 420 Westwood Plaza, 48-121 Engineering IV, Los Angeles, CA 90095-1597, USA.

ABSTRACT
An image-patterned molecular delivery system for mammalian cells is demonstrated by pulsed laser irradiation of gold particles immobilized on a substrate below a cell monolayer. Patterned cavitation bubble nucleation was captured using a time-resolved imaging system and molecular delivery verified by observing the uptake of a membrane-impermeable fluorescent dye, calcein. Delivery efficiency as high as 90% was observed and multiplexed, patterned dye delivery was demonstrated.

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Image patterned bubble nucleation. (a) Bubble pattern by irradiating a “UCLA” light pattern onto the substrate. Laser fluence = 153.5 mJ/cm2. Bar = 50 µm. (b) Bubble nucleation (indicated by red arrows) was observed at laser fluences higher than 39 mJ/cm2. Field of view = 10×10 μm. (c) Calculated temperature increase at the surface of the gold particle (50, 118 and 200 nm in diameter) at the end of the 6 ns laser pulse under various laser fluences.
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g004: Image patterned bubble nucleation. (a) Bubble pattern by irradiating a “UCLA” light pattern onto the substrate. Laser fluence = 153.5 mJ/cm2. Bar = 50 µm. (b) Bubble nucleation (indicated by red arrows) was observed at laser fluences higher than 39 mJ/cm2. Field of view = 10×10 μm. (c) Calculated temperature increase at the surface of the gold particle (50, 118 and 200 nm in diameter) at the end of the 6 ns laser pulse under various laser fluences.

Mentions: To model this energy transduction process, we used Mie theory [12,13] to calculate the absorption coefficient, Qabs, of gold spheres of different diameters in water. The refractive index of gold was taken from Johnson and Christy [14] with at . The refractive index of water was . We calculated Qabs=3.34, 2.14 and 1.65 for gold spheres of diameter 50 nm, 118 nm and 200 nm, respectively. To simplify the analysis and yet obtain insightful solutions, we modeled the system as a gold sphere immersed in an infinite water medium. The temperature increase in the sphere due to the absorbed laser energy can be determined by solving the heat equation, Eq. (1):∂T∂t−κ∇2T=Aρcp(1)where T is the temperature increase, ρ is the density, is the specific heat, and κis the thermal diffusivity of gold. A is the heat generation rate per unit time per unit volume and was modeled by Eq. (2) (assuming spatial and temporal homogeneous heat deposition within the particle):A=(πR2)Qabs43πR3⋅Hτpulse=3QabsH4Rτpulse(2)where H is the laser fluence, τpulse is the laser pulsewidth, and R is the particle radius. Using the analytical solution obtained by Goldenberg and Tranter [15], the calculated temperature increase at the surface of the gold particle is linearly proportional to the irradiation laser fluence (Fig. 4(c)Fig. 4


Image patterned molecular delivery into live cells using gold particle coated substrates.

Wu TH, Kalim S, Callahan C, Teitell MA, Chiou PY - Opt Express (2010)

Image patterned bubble nucleation. (a) Bubble pattern by irradiating a “UCLA” light pattern onto the substrate. Laser fluence = 153.5 mJ/cm2. Bar = 50 µm. (b) Bubble nucleation (indicated by red arrows) was observed at laser fluences higher than 39 mJ/cm2. Field of view = 10×10 μm. (c) Calculated temperature increase at the surface of the gold particle (50, 118 and 200 nm in diameter) at the end of the 6 ns laser pulse under various laser fluences.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369548&req=5

g004: Image patterned bubble nucleation. (a) Bubble pattern by irradiating a “UCLA” light pattern onto the substrate. Laser fluence = 153.5 mJ/cm2. Bar = 50 µm. (b) Bubble nucleation (indicated by red arrows) was observed at laser fluences higher than 39 mJ/cm2. Field of view = 10×10 μm. (c) Calculated temperature increase at the surface of the gold particle (50, 118 and 200 nm in diameter) at the end of the 6 ns laser pulse under various laser fluences.
Mentions: To model this energy transduction process, we used Mie theory [12,13] to calculate the absorption coefficient, Qabs, of gold spheres of different diameters in water. The refractive index of gold was taken from Johnson and Christy [14] with at . The refractive index of water was . We calculated Qabs=3.34, 2.14 and 1.65 for gold spheres of diameter 50 nm, 118 nm and 200 nm, respectively. To simplify the analysis and yet obtain insightful solutions, we modeled the system as a gold sphere immersed in an infinite water medium. The temperature increase in the sphere due to the absorbed laser energy can be determined by solving the heat equation, Eq. (1):∂T∂t−κ∇2T=Aρcp(1)where T is the temperature increase, ρ is the density, is the specific heat, and κis the thermal diffusivity of gold. A is the heat generation rate per unit time per unit volume and was modeled by Eq. (2) (assuming spatial and temporal homogeneous heat deposition within the particle):A=(πR2)Qabs43πR3⋅Hτpulse=3QabsH4Rτpulse(2)where H is the laser fluence, τpulse is the laser pulsewidth, and R is the particle radius. Using the analytical solution obtained by Goldenberg and Tranter [15], the calculated temperature increase at the surface of the gold particle is linearly proportional to the irradiation laser fluence (Fig. 4(c)Fig. 4

Bottom Line: An image-patterned molecular delivery system for mammalian cells is demonstrated by pulsed laser irradiation of gold particles immobilized on a substrate below a cell monolayer.Patterned cavitation bubble nucleation was captured using a time-resolved imaging system and molecular delivery verified by observing the uptake of a membrane-impermeable fluorescent dye, calcein.Delivery efficiency as high as 90% was observed and multiplexed, patterned dye delivery was demonstrated.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, University of California, Los Angeles (UCLA), 420 Westwood Plaza, 48-121 Engineering IV, Los Angeles, CA 90095-1597, USA.

ABSTRACT
An image-patterned molecular delivery system for mammalian cells is demonstrated by pulsed laser irradiation of gold particles immobilized on a substrate below a cell monolayer. Patterned cavitation bubble nucleation was captured using a time-resolved imaging system and molecular delivery verified by observing the uptake of a membrane-impermeable fluorescent dye, calcein. Delivery efficiency as high as 90% was observed and multiplexed, patterned dye delivery was demonstrated.

Show MeSH
Related in: MedlinePlus