title: Path-programmable water droplet manipulations on an adhesion controlled superhydrophobic surface.
abstract: Here, we developed a novel and facile method to control the local water adhesion force of a thin and stretchable superhydrophobic polydimethylsiloxane (PDMS) substrate with micro-pillar arrays that allows the individual manipulation of droplet motions including moving, merging and mixing. When a vacuum pressure was applied below the PDMS substrate, a local dimple structure was formed and the water adhesion force of structure was significantly changed owing to the dynamically varied pillar density. With the help of the lowered water adhesion force and the slope angle of the formed dimple structure, the motion of individual water droplets could be precisely controlled, which facilitated the creation of a droplet-based microfluidic platform capable of a programmable manipulation of droplets. We showed that the platform could be used in newer and emerging microfluidic operations such as surface-enhanced Raman spectroscopy with extremely high sensing capability (10(-15) M) and in vitro small interfering RNA transfection with enhanced transfection efficiency of ~80%.
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Jungmok
authors.initials: J
authors.lastname: Seo
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Seoung-Ki
authors.initials: SK
authors.lastname: Lee
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Jaehong
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Jung
authors.initials: J
authors.lastname: Seung Lee
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Hyukho
authors.initials: H
authors.lastname: Kwon
authors.affiliation: Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Seung-Woo
authors.initials: SW
authors.lastname: Cho
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Ahn
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Taeyoon
authors.initials: T
authors.lastname: Lee
mesh_terms: D000268:Adhesiveness; D015374:Biosensing Techniques / Q000295:instrumentation*; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D057927:Hydrophobic and Hydrophilic Interactions; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods*; D008846:Micromanipulation / Q000295:instrumentation*; D013499:Surface Properties; D014618:Vacuum; D014867:Water / Q000737:chemistry*
chemical_list: D004129:Dimethylpolysiloxanes; D014867:Water; C013830:baysilon