Electrosonic ejector microarray for drug and gene delivery

Abstract

We report on development and experimental characterization of a novel cell manipulation device-the electrosonic ejector microarray-which establishes a pathway for drug and/or gene delivery with control of biophysical action on the length scale of an individual cell. The device comprises a piezoelectric transducer for ultrasound wave generation, a reservoir for storing the sample mixture and a set of acoustic horn structures that form a nozzle array for focused application of mechanical energy. The nozzles are micromachined in silicon or plastic using simple and economical batch fabrication processes. When the device is driven at a particular resonant frequency of the acoustic horn structures, the sample mixture of cells and desired transfection agents/molecules suspended in culture medium is ejected from orifices located at the nozzle tips. During sample ejection, focused mechanical forces (pressure and shear) are generated on a microsecond time scale (dictated by nozzle size/geometry and ejection velocity) resulting in identical "active" microenvironments for each ejected cell. This process enables a number of cellular bioeffects, from uptake of small molecules and gene delivery/transfection to cell lysis. Specifically, we demonstrate successful calcein uptake and transfection of DNA plasmid encoding green fluorescent protein (GFP) into human malignant glioma cells (cell line LN443) using electrosonic microarrays with 36, 45 and 50 mum diameter nozzle orifices and operating at ultrasound frequencies between 0.91 and 0.98 MHz. Our results suggest that efficacy and the extent of bioeffects are mainly controlled by nozzle orifice size and the localized intensity of the applied acoustic field.

Faraday instability-based micro droplet ejection for inhalation drug delivery

“…Some examples of such applications include synthesis of nano particles via spray pyrolysis, sample injection in chemical analysis (e.g. mass spectroscopy), high-quality thin-film coating, 45 3-D photoresist coating of micro- and nano-structures in fabrication of nano-electronic and -photonic devices, fuel injection in combustion, delivery of lipid-based micro-encapsulated biological entities or gene, 46,47 pharmaceutical preparation such as double emulsion, 48,49 rapid heat removal in laser surgery, and rapid administration of cosmetics.…”

Photoporation Using Carbon Nanotubes for Intracellular Delivery of Molecules and Its Relationship to Photoacoustic Pressure

“…The CB, SWCNT, and MWCNT concentrations were selected as ones that exhibited the same light transmittance under our laser exposure conditions, as determined by spectrophotometry. Following precedent in many prior studies of photoporation and other methods of intracellular delivery, calcein was selected as an intracellular uptake marker because it does not cross intact cell membranes well, but can cross permeabilized cell membranes and is retained inside cells if the cell membrane reseals. Herein, delivery of other molecules into cells, such as macromolecules, was not studied because the goal of this study was to determine factors that affect cell membrane permeabilization leading the intracellular uptake in general.…”

Micrometer-sized droplet ejection from a millimeter-sized spherical water drop using a megahertz multiple-fourier horn ultrasonic nozzle

“…Therefore, the resulting technology for the generation of micrometer-sized monodisperse droplets at high-throughput and low electrical drive power reported here has an imminent application to inhalation drug delivery [12]. Other potential applications include nanoparticle synthesis [24], gene delivery [25], 3D coating of micro-and nano-structures, fuel injection [26], and pharmaceutical applications such as double emulsion [27].…”