title: Intracellular delivery of molecules using microfabricated nanoneedle arrays.
abstract: Many bioactive molecules have intracellular targets, but have difficulty crossing the cell membrane to reach those targets. To address this difficulty, we fabricated arrays of nanoneedles to gently and simultaneously puncture 10(5) cells and thereby provide transient pathways for transport of molecules into the cells. The nanoneedles were microfabricated by etching silicon to create arrays of nanoneedles measuring 12 μm in height, tapering to a sharp tip less than 30 nm wide to facilitate puncture into cells and spaced 10 μm apart in order to have at least one nanoneedle puncture each cell in a confluent monolayer. These nanoneedles were used for intracellular delivery in two ways: puncture loading, in which nanoneedle arrays were pressed into cell monolayers, and centrifuge loading, in which cells in suspension were spun down onto nanoneedle arrays. The effects on intracellular uptake and cell viability were determined as a function of nanoneedle length and sharpness, puncture force and duration, and molecular weight of the molecule delivered. Under optimal conditions, intracellular uptake was seen in approximately 50 % of cells while maintaining high cell viability. Overall, this study provides a comparative analysis of intracellular delivery using nanoneedle arrays by two different loading methods over a range of operating parameters.
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
authors.forename: Seonhee
authors.initials: S
authors.lastname: Park
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.|Nanotechnology Innovation Center of Kansas State, Kansas State University, Manhattan, KS, 66506, USA.
authors.forename: Seong-O
authors.initials: SO
authors.lastname: Choi
authors.affiliation: School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
authors.forename: Seung-joon
authors.initials: SJ
authors.lastname: Paik
authors.affiliation: School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.|School of Science, Technology, Engineering and Mathematics, University of Washington Bothell, Bothell, WA, 98011, USA.
authors.forename: Seungkeun
authors.initials: S
authors.lastname: Choi
authors.affiliation: School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.|Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Allen
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA. prausnitz@gatech.edu.
authors.forename: Mark
authors.initials: M
authors.lastname: Prausnitz
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival; D016503:Drug Delivery Systems / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D008297:Male; D049329:Nanostructures; D009339:Needles
keywords: Centrifuge loading; Intracellular delivery; Microfabricated nanoneedle array; Microneedle; Puncture loading