Optical and electron microscopy study of laser-based intracellular molecule delivery using peptide-conjugated photodispersible gold nanoparticle agglomerates
Creators: name: Krawinkel, Judith
name: Richter, Undine
name: Torres-Mapa, Maria Leilani
name: Westermann, Martin
name: Gamrad, Lisa
name: Rehbock, Christoph
name: Barcikowski, Stephan
name: Heisterkamp, Alexander
Publisher: name: London : BioMed Central Ltd.
Year: 2016
Subjects: subject: Cell-penetrating peptides
subject: Endosomes
subject: Gold nanoparticles
subject: Intracellular molecule delivery
subject: Laser-based release
subject: Particle agglomerates
subject: Agglomeration
subject: Cell proliferation
subject: Cells
subject: Cytology
subject: Electron microscopy
subject: Fiber optic sensors
subject: Gold
subject: High resolution transmission electron microscopy
subject: Irradiation
subject: Laser ablation
subject: Medical applications
subject: Metal nanoparticles
subject: Molecular biology
subject: Molecules
subject: Nanoparticles
subject: Peptides
subject: Transmission electron microscopy
subject: Cell-penetrating peptide
subject: Gold Nanoparticles
subject: Laser-based
subject: Pulsed lasers
subject: calcein
subject: cell penetrating peptide
subject: gold nanoparticle
subject: animal cell
subject: Article
subject: cell proliferation
subject: cell viability
subject: cellular distribution
subject: conjugation
subject: controlled study
subject: cytoplasm
subject: drug cytotoxicity
subject: electron microscopy
subject: endocytosis
subject: endosome
subject: laser
subject: membrane damage
subject: microscopy
subject: nonhuman
subject: transmission electron microscopy
subject: Dewey Decimal Classification::500 | Naturwissenschaften::570 | Biowissenschaften, Biologie
subject: Dewey Decimal Classification::600 | Technik::610 | Medizin, Gesundheit

description: Background: Cell-penetrating peptides (CPPs) can act as carriers for therapeutic molecules such as drugs and genetic constructs for medical applications. The triggered release of the molecule into the cytoplasm can be crucial to its effective delivery. Hence, we implemented and characterized laser interaction with defined gold nanoparticle agglomerates conjugated to CPPs which enables efficient endosomal rupture and intracellular release of molecules transported. Results: Gold nanoparticles generated by pulsed laser ablation in liquid were conjugated with CPPs forming agglomerates and the intracellular release of molecules was triggered via pulsed laser irradiation (λ = 532 nm, τpulse = 1 ns). The CPPs enhance the uptake of the agglomerates along with the cargo which can be co-incubated with the agglomerates. The interaction of incident laser light with gold nanoparticle agglomerates leads to heat deposition and field enhancement in the vicinity of the particles. This highly precise effect deagglomerates the nanoparticles and disrupts the enclosing endosomal membrane. Transmission electron microscopy images confirmed this rupture for radiant exposures of 25 mJ/cm2 and above. Successful intracellular release was shown using the fluorescent dye calcein. For a radiant exposure of 35 mJ/cm2 we found calcein delivery in 81 % of the treated cells while maintaining a high percentage of cell viability. Furthermore, cell proliferation and metabolic activity were not reduced 72 h after the treatment. Conclusion: CPPs trigger the uptake of the gold nanoparticle agglomerates via endocytosis and co-resident molecules in the endosomes are released by applying laser irradiation, preventing their intraendosomal degradation. Due to the highly localized effect, the cell membrane integrity is not affected. Therefore, this technique can be an efficient tool for spatially and temporally confined intracellular release. The utilization of specifically designed photodispersible gold nanoparticle agglomerates (65 nm) can open novel avenues in imaging and molecule delivery. Due to the induced deagglomeration the primary, small particles (~5 nm) are more likely to be removed from the body.