Toward Contactless Biology: Acoustophoretic DNA Transfection.

Thomas Vasileiou,Adem Bayram,Dimos Poulikakos,Daniele Foresti,Aldo Ferrari

doi:10.1038/srep20023

Thomas Vasileiou, Adem Bayram + Show 3 more

Open Access

https://doi.org/10.1038/srep20023

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Abstract

Acoustophoresis revolutionized the field of container-less manipulation of liquids and solids by enabling mixing procedures which avoid contamination and loss of reagents due to the contact with the support. While its applications to chemistry and engineering are straightforward, additional developments are needed to obtain reliable biological protocols in a contactless environment. Here, we provide a first, fundamental step towards biological reactions in air by demonstrating the acoustophoretic DNA transfection of mammalian cells. We developed an original acoustophoretic design capable of levitating, moving and mixing biological suspensions of living mammalians cells and of DNA plasmids. The precise and sequential delivery of the mixed solutions into tissue culture plates is actuated by a novel mechanism based on the controlled actuation of the acoustophoretic force. The viability of the contactless procedure is tested using a cellular model sensitive to small perturbation of neuronal differentiation pathways. Additionally, the efficiency of the transfection procedure is compared to standard, container-based methods for both single and double DNA transfection and for different cell types including adherent growing HeLa cancer cells, and low adhesion neuron-like PC12 cells. In all, this work provides a proof of principle which paves the way to the development of high-throughput acoustophoretic biological reactors.

Highlights

Acoustophoresis revolutionized the field of container-less manipulation of liquids and solids by enabling mixing procedures which avoid contamination and loss of reagents due to the contact with the support
Emitters operating at different planes were excited with a phase difference of 180o whereas those in the same plane were excited in phase, such as the interference of the acoustic waves acted in a constructive manner
As a first step in this direction, here we provide basic experimental proof on the application of acoustophoretic handling in molecular biology

Summary

Introduction

Acoustophoresis revolutionized the field of container-less manipulation of liquids and solids by enabling mixing procedures which avoid contamination and loss of reagents due to the contact with the support. The acoustic streaming induces vortices inside the levitated droplet, enhancing the mixing[8] The application of this methodology to molecular and cellular biology promises to significantly reduce the use of reagents and would allow for new categories of biological substrate-free studies. A typical indicator of cell viability is the study of the cytotoxicity of chemical or physical treatments of eukaryotic cells, generally assessed via commercial, live or dead assays[13,14] These tests are based on the cell permeation of fluorescent compounds signaling the alteration of the membrane structure, which takes place in the early phases of apoptosis[14]. While these assays reliably report on the viability of a manipulation procedure, they fail to detect more subtle levels of toxicity interfering with the cell metabolism, differentiation and functionality

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