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In vitro perforation of human epithelial carcinoma cell with antibody-conjugated biodegradable microspheres illuminated by a single 80 femtosecond near-infrared laser pulse.

Terakawa M, Tsunoi Y, Mitsuhashi T - Int J Nanomedicine (2012)

Bottom Line: A polylactic acid (PLA) sphere, a biodegradable polymer, was used.Fluorescein isothiocyanate (FITC)-dextran and short interfering RNA were delivered into many human epithelial carcinoma cells (A431 cells) by applying a single 80 fs laser pulse in the presence of antibody-conjugated PLA microspheres.Perforation by biodegradable spheres compared with other particles has the potential to be a much safer phototherapy and drug delivery method for patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronics and Electrical Engineering, Keio University, Yokohama, Kanagawa, Japan. terakawa@elec.keio.ac.jp

ABSTRACT
Pulsed laser interaction with small metallic and dielectric particles has been receiving attention as a method of drug delivery to many cells. However, most of the particles are attended by many risks, which are mainly dependent upon particle size. Unlike other widely used particles, biodegradable particles have advantages of being broken down and eliminated by innate metabolic processes. In this paper, the perforation of cell membrane by a focused spot with transparent biodegradable microspheres excited by a single 800 nm, 80 fs laser pulse is demonstrated. A polylactic acid (PLA) sphere, a biodegradable polymer, was used. Fluorescein isothiocyanate (FITC)-dextran and short interfering RNA were delivered into many human epithelial carcinoma cells (A431 cells) by applying a single 80 fs laser pulse in the presence of antibody-conjugated PLA microspheres. The focused intensity was also simulated by the three-dimensional finite-difference time-domain method. Perforation by biodegradable spheres compared with other particles has the potential to be a much safer phototherapy and drug delivery method for patients. The present method can open a new avenue, which is considered an efficient adherent for the selective perforation of cells which express the specific antigen on the cell membrane.

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(A–D) Optical intensity distributions on the yz plane simulated by the three-dimensional finite-difference time-domain method for PLA spheres of different diameters: (A) 250 nm, (B) 500 nm, (C) 1000 nm, and (D) 2000 nm. A plane wave is illuminated to the sphere with the wave vector in the z direction. The incident wave of 800 nm in wavelength is linearly polarized along the x-axis. (E–G) Optical intensity distributions along (E) the z-axis under the sphere, (F) the x-axis under the sphere on the peak intensity, shown as red horizontal line in A–D, and (G) the y-axis under the sphere on the peak intensity. (H) Relative positions of focused far field, PLA sphere, and cell membrane on yz plane in the case of 2000 nm PLA sphere. Note: Dashed circle and gray plane indicate the positions of the PLA sphere and the cell membrane, respectively.Abbreviations: FWHM, Width at half maximum; PLA, polylactic acid.
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f2-ijn-7-2653: (A–D) Optical intensity distributions on the yz plane simulated by the three-dimensional finite-difference time-domain method for PLA spheres of different diameters: (A) 250 nm, (B) 500 nm, (C) 1000 nm, and (D) 2000 nm. A plane wave is illuminated to the sphere with the wave vector in the z direction. The incident wave of 800 nm in wavelength is linearly polarized along the x-axis. (E–G) Optical intensity distributions along (E) the z-axis under the sphere, (F) the x-axis under the sphere on the peak intensity, shown as red horizontal line in A–D, and (G) the y-axis under the sphere on the peak intensity. (H) Relative positions of focused far field, PLA sphere, and cell membrane on yz plane in the case of 2000 nm PLA sphere. Note: Dashed circle and gray plane indicate the positions of the PLA sphere and the cell membrane, respectively.Abbreviations: FWHM, Width at half maximum; PLA, polylactic acid.

Mentions: Figure 2 shows the optical intensity distribution at 800 nm wavelength under the PLA microsphere calculated by the 3D FDTD method. The optical near field in the vicinity of the PLA sphere with diameters of 250 and 500 nm is governed mainly by the Mie scattering process. The optical enhancement by the Mie scattering is basically dependent upon the size parameter α = 2πR/λ, where R is the sphere radius and λ is the incident wavelength. The low enhancement factors obtained with sphere diameters of 250 and 500 nm are attributed to the off-resonant Mie scattering regime and the low refractive index difference between PLA sphere (n = 1.45) and water (n = 1.326) at 800 nm wavelength.24,26 The underlying physics for enhanced optical field under the sphere shifts from Mie resonance scattering domain to microlens effect with the increase of the sphere diameter. The enhancement factor obtained with the PLA sphere diameter of 1000 nm is 4.0 in relation to the incident optical intensity, while that obtained with the PS sphere of 1000 nm diameter is enhanced to be 8.4.23 The higher enhancement factor with the PS sphere is explained by the higher refractive index of the PS sphere (n = 1.577) compared with the PLA sphere.26 The PLA sphere of 2000 nm diameter mainly behaves as a microlens and the optical intensity is enhanced by a factor of 9.7 in relation to the incident optical intensity at 870 nm under the sphere (Figure 2D). Based on the optical intensity distribution, the spheres conjugate to the top surface of the cell work for the perforation, while those conjugate to the side surface may not. The full width at half maximums (FWHMs) on the x- and y-axes were 609 and 551 nm, respectively, suggesting that the submicrometer pores may be formed on the cell membrane.


In vitro perforation of human epithelial carcinoma cell with antibody-conjugated biodegradable microspheres illuminated by a single 80 femtosecond near-infrared laser pulse.

Terakawa M, Tsunoi Y, Mitsuhashi T - Int J Nanomedicine (2012)

(A–D) Optical intensity distributions on the yz plane simulated by the three-dimensional finite-difference time-domain method for PLA spheres of different diameters: (A) 250 nm, (B) 500 nm, (C) 1000 nm, and (D) 2000 nm. A plane wave is illuminated to the sphere with the wave vector in the z direction. The incident wave of 800 nm in wavelength is linearly polarized along the x-axis. (E–G) Optical intensity distributions along (E) the z-axis under the sphere, (F) the x-axis under the sphere on the peak intensity, shown as red horizontal line in A–D, and (G) the y-axis under the sphere on the peak intensity. (H) Relative positions of focused far field, PLA sphere, and cell membrane on yz plane in the case of 2000 nm PLA sphere. Note: Dashed circle and gray plane indicate the positions of the PLA sphere and the cell membrane, respectively.Abbreviations: FWHM, Width at half maximum; PLA, polylactic acid.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368514&req=5

f2-ijn-7-2653: (A–D) Optical intensity distributions on the yz plane simulated by the three-dimensional finite-difference time-domain method for PLA spheres of different diameters: (A) 250 nm, (B) 500 nm, (C) 1000 nm, and (D) 2000 nm. A plane wave is illuminated to the sphere with the wave vector in the z direction. The incident wave of 800 nm in wavelength is linearly polarized along the x-axis. (E–G) Optical intensity distributions along (E) the z-axis under the sphere, (F) the x-axis under the sphere on the peak intensity, shown as red horizontal line in A–D, and (G) the y-axis under the sphere on the peak intensity. (H) Relative positions of focused far field, PLA sphere, and cell membrane on yz plane in the case of 2000 nm PLA sphere. Note: Dashed circle and gray plane indicate the positions of the PLA sphere and the cell membrane, respectively.Abbreviations: FWHM, Width at half maximum; PLA, polylactic acid.
Mentions: Figure 2 shows the optical intensity distribution at 800 nm wavelength under the PLA microsphere calculated by the 3D FDTD method. The optical near field in the vicinity of the PLA sphere with diameters of 250 and 500 nm is governed mainly by the Mie scattering process. The optical enhancement by the Mie scattering is basically dependent upon the size parameter α = 2πR/λ, where R is the sphere radius and λ is the incident wavelength. The low enhancement factors obtained with sphere diameters of 250 and 500 nm are attributed to the off-resonant Mie scattering regime and the low refractive index difference between PLA sphere (n = 1.45) and water (n = 1.326) at 800 nm wavelength.24,26 The underlying physics for enhanced optical field under the sphere shifts from Mie resonance scattering domain to microlens effect with the increase of the sphere diameter. The enhancement factor obtained with the PLA sphere diameter of 1000 nm is 4.0 in relation to the incident optical intensity, while that obtained with the PS sphere of 1000 nm diameter is enhanced to be 8.4.23 The higher enhancement factor with the PS sphere is explained by the higher refractive index of the PS sphere (n = 1.577) compared with the PLA sphere.26 The PLA sphere of 2000 nm diameter mainly behaves as a microlens and the optical intensity is enhanced by a factor of 9.7 in relation to the incident optical intensity at 870 nm under the sphere (Figure 2D). Based on the optical intensity distribution, the spheres conjugate to the top surface of the cell work for the perforation, while those conjugate to the side surface may not. The full width at half maximums (FWHMs) on the x- and y-axes were 609 and 551 nm, respectively, suggesting that the submicrometer pores may be formed on the cell membrane.

Bottom Line: A polylactic acid (PLA) sphere, a biodegradable polymer, was used.Fluorescein isothiocyanate (FITC)-dextran and short interfering RNA were delivered into many human epithelial carcinoma cells (A431 cells) by applying a single 80 fs laser pulse in the presence of antibody-conjugated PLA microspheres.Perforation by biodegradable spheres compared with other particles has the potential to be a much safer phototherapy and drug delivery method for patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronics and Electrical Engineering, Keio University, Yokohama, Kanagawa, Japan. terakawa@elec.keio.ac.jp

ABSTRACT
Pulsed laser interaction with small metallic and dielectric particles has been receiving attention as a method of drug delivery to many cells. However, most of the particles are attended by many risks, which are mainly dependent upon particle size. Unlike other widely used particles, biodegradable particles have advantages of being broken down and eliminated by innate metabolic processes. In this paper, the perforation of cell membrane by a focused spot with transparent biodegradable microspheres excited by a single 800 nm, 80 fs laser pulse is demonstrated. A polylactic acid (PLA) sphere, a biodegradable polymer, was used. Fluorescein isothiocyanate (FITC)-dextran and short interfering RNA were delivered into many human epithelial carcinoma cells (A431 cells) by applying a single 80 fs laser pulse in the presence of antibody-conjugated PLA microspheres. The focused intensity was also simulated by the three-dimensional finite-difference time-domain method. Perforation by biodegradable spheres compared with other particles has the potential to be a much safer phototherapy and drug delivery method for patients. The present method can open a new avenue, which is considered an efficient adherent for the selective perforation of cells which express the specific antigen on the cell membrane.

Show MeSH
Related in: MedlinePlus