Dataset Information

In Situ Transfection by Controlled Release of Lipoplexes Using Acoustic Droplet Vaporization.

ABSTRACT: Localized delivery of nucleic acids to target sites (e.g., diseased tissue) is critical for safe and efficacious gene therapy. An ultrasound-based technique termed acoustic droplet vaporization (ADV) has been used to spatiotemporally control the release of therapeutic small molecules and proteins contained within sonosensitive emulsions. Here, ADV is used to control the release of lipoplex-containing plasmid DNA encoding an enhanced green fluorescent protein reporter-from a sonosensitive emulsion. Focused ultrasound (3.5 MHz, mechanical index (MI) ? 1.5) generates robust release of fluorescein (i.e., surrogate payload) and lipoplex from the emulsion. In situ release of the lipoplex from the emulsion using ADV (MI = 1.5, 30 cycles) yields a 55% release efficiency, resulting in 43% transfection efficiency and 95% viability with C3H/10T1/2 cells. Without exposure to ultrasound, the release and transfection efficiencies are 5% and 7%, respectively, with 99% viability. Lipoplex released by ADV retains its bioactivity while the ADV process does not yield any measureable sonoporative enhancement of transfection. Co-encapsulation of Ficoll PM 400 within the lipoplex-loaded emulsion, and its subsequent release using ADV, yield higher transfection efficiency than the lipoplex alone. The results demonstrate that ADV can have utility in the spatiotemporal control of gene delivery.

SUBMITTER: Juliar BA

PROVIDER: S-EPMC4956527 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

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In Situ Transfection by Controlled Release of Lipoplexes Using Acoustic Droplet Vaporization.

Juliar Benjamin A BA Bromley Melissa M MM Moncion Alexander A Jones Denise C DC O'Neill Eric G EG Wilson Christopher G CG Franceschi Renny T RT Fabiilli Mario L ML

Advanced healthcare materials 20160518 14

Localized delivery of nucleic acids to target sites (e.g., diseased tissue) is critical for safe and efficacious gene therapy. An ultrasound-based technique termed acoustic droplet vaporization (ADV) has been used to spatiotemporally control the release of therapeutic small molecules and proteins contained within sonosensitive emulsions. Here, ADV is used to control the release of lipoplex-containing plasmid DNA encoding an enhanced green fluorescent protein reporter-from a sonosensitive emulsio ...[more]

PMID: 27191532

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Project description:The challenge of translating pro-angiogenic growth factors for therapeutic purposes has stimulated a myriad of biomaterials-based, delivery approaches. Many techniques rely on incorporating a growth factor into a hydrogel. The kinetics of release can be tuned based on the physiochemical properties of the growth factor and scaffold. We have developed an acoustically-responsive scaffold (ARS), whereby release of a growth factor is non-invasively and spatiotemporally controlled in an on-demand manner using focused ultrasound. An ARS consists of a fibrin matrix doped with a growth factor-loaded, sonosensitive emulsion. In this study, we used an ARS to investigate the impact of basic fibroblast growth factor (bFGF) release on endothelial tubule formation. The co-culture model of angiogenic sprouting consisted of endothelial cell-coated microbeads and dispersed fibroblasts. bFGF release correlated with the acoustic pressure applied while sprout length correlated with both the volume of bFGF-loaded emulsion in the ARS and acoustic pressure. Minimal bFGF release and sprouting were observed in the absence of ultrasound exposure. Staggering the release of bFGF via multiple ultrasound exposures did not affect sprouting. Additionally, sprouting did not display a dependence on the distance between each microbead and the ARS. Overall, these results highlight the potential of using ultrasound to control regenerative processes via the controlled delivery of a growth factor. STATEMENT OF SIGNIFICANCE: Due to the ineffectiveness of conventional routes of administration, implantable hydrogels are often used as matrices to deliver growth factors (GFs). Spatial control of release is typically realized using anisotropic constructs while temporal control is obtained by modifying matrix properties and GF-scaffold interactions. In this study, we demonstrate how focused ultrasound can be used to non-invasively and spatiotemporally control release of basic fibroblast growth factor (bFGF), in an on-demand manner, from a composite hydrogel. The acoustically-responsive scaffold (ARS) consists of a bFGF-loaded, monodispersed double emulsion embedded within a fibrin matrix. We demonstrate how controlled release of bFGF can stimulate endothelial network formation. These results may be of interest to groups working on controlled release strategies for GFs, especially in the context of stimulating angiogenesis.

Project description:One of the major challenges in developing acoustic droplet vaporization (ADV)-associated therapy as an effective and safe strategy is the precise determination of the spatial cellular bioeffects after ADV (cell death or cell membrane permeabilization). In this study, we combined high-speed camera imaging and live-cell microscopic imaging to observe the transient dynamics of droplets during ADV and to evaluate the mechanical force on cells. Methods: C6 glioma cells were co-incubated with DiI-labeled droplets (radius: 1.5, 2.25, and 3.0 μm). We used an acousto-optical system for high-speed bright-field (500 kfps) and fluorescence (40 kfps) microscopic imaging in order to visualize the dynamics of droplets under ultrasound excitation (frequency = 5 MHz, pressure = 5-8 MPa, cycle number = 3, pulse number = 1). Live-cell microscopic imaging was used to monitor the cell morphology, cell membrane permeabilization, and cell viability by membrane-anchored Lyn-yellow fluorescence protein, propidium Iodide staining, and calcein blue AM staining, respectively. Results: We discovered that the spatial distribution of ADV-induced bioeffects could be mapped to the physical dynamics of droplet vaporization. For droplets with a 1.5 μm radius, the distance threshold for ADV-induced cell death (5.5±1.9 μm) and reversible membrane permeabilization (11.3±3.5 μm) was well correlated with the distance of ADV-bubble pressing downward to the floor (5.7±1.3 μm) and maximum distance of droplet expansion (11.5±2.6 μm), respectively. These distances were enlarged by increasing the droplet sizes and insonation acoustic pressures. The live-cell imaging results show that ADV-bubbles can directly disrupt the cell membrane layer and induce intensive intracellular substance leakage. Further, the droplets shed the payload onto nearby cells during ADV, suggesting ADV could directly induce adjacent cell death by physical force and enhancement of chemotherapy to distant cells. Conclusion: This study provide new insights into the ADV-mediated physicochemical synergic effect for medical applications.

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In Situ Transfection by Controlled Release of Lipoplexes Using Acoustic Droplet Vaporization.

Publications

In Situ Transfection by Controlled Release of Lipoplexes Using Acoustic Droplet Vaporization.

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