title: Thermal gradient induced tweezers for the manipulation of particles and cells.
abstract: Optical tweezers are a well-established tool for manipulating small objects. However, their integration with microfluidic devices often requires an objective lens. More importantly, trapping of non-transparent or optically sensitive targets is particularly challenging for optical tweezers. Here, for the first time, we present a photon-free trapping technique based on electro-thermally induced forces. We demonstrate that thermal-gradient-induced thermophoresis and thermal convection can lead to trapping of polystyrene spheres and live cells. While the subject of thermophoresis, particularly in the micro- and nano-scale, still remains to be fully explored, our experimental results have provided a reasonable explanation for the trapping effect. The so-called thermal tweezers, which can be readily fabricated by femtosecond laser writing, operate with low input power density and are highly versatile in terms of device configuration, thus rendering high potential for integration with microfluidic devices as well as lab-on-a-chip systems.
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: Jiajie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: Hengji
authors.initials: H
authors.lastname: Cong
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.|Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: Jacky
authors.initials: J
authors.lastname: Loo
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Kang
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: Minghui
authors.initials: M
authors.lastname: Tang
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: Haixi
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: Shu-Yuen
authors.initials: SY
authors.lastname: Wu
authors.affiliation: Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: Siu-Kai
authors.initials: SK
authors.lastname: Kong
authors.affiliation: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: Ho-Pui
authors.initials: HP
authors.lastname: Ho
mesh_terms: D006358:Hot Temperature; D056656:Lab-On-A-Chip Devices; D052898:Optical Tweezers