Electrostatic tweezer for droplet manipulation

Yuankai Jin; Wanghuai Xu; Huanhuan Zhang; Ruirui Li; Jing Sun; Siyan Yang; Minjie Liu; Haiyang Mao; Zuankai Wang

doi:10.1073/pnas.2105459119

Electrostatic tweezer for droplet manipulation

Yuankai Jin, Wanghuai Xu, Huanhuan Zhang, Ruirui Li, Jing Sun, Siyan Yang, Minjie Liu, Haiyang Mao, Zuankai Wang

Department of Electrical and Electronic Engineering

Research output: Journal article publication › Journal article › Academic research › peer-review

80 Citations (Scopus)

Abstract

Various physical tweezers for manipulating liquid droplets based on optical, electrical, magnetic, acoustic, or other external fields have emerged and revolutionized research and application in medical, biological, and environmental fields. Despite notable progress, the existing modalities for droplet control and manipulation are still limited by the extra responsive additives and relatively poor controllability in terms of droplet motion behaviors, such as distance, velocity, and direction. Herein, we report a versatile droplet electrostatic tweezer (DEST) for remotely and programmatically trapping or guiding the liquid droplets under diverse conditions, such as in open and closed spaces and on flat and tilted surfaces as well as in oil medium. DEST, leveraging on the coulomb attraction force resulting from its electrostatic induction to a droplet, could manipulate droplets of various compositions, volumes, and arrays on various substrates, offering a potential platform for a series of applications, such as high-throughput surface-enhanced Raman spectroscopy detection with single measuring time less than 20 s.

Original language	English
Article number	e2105459119
Journal	Proceedings of the National Academy of Sciences of the United States of America
Volume	119
Issue number	2
DOIs	https://doi.org/10.1073/pnas.2105459119
Publication status	Published - 11 Jan 2022

Keywords

Droplet manipulation
Electrostatic induction
SERS
Tweezer

ASJC Scopus subject areas

General

More information

10.1073/pnas.2105459119

Cite this

@article{2ab50fc576a54007a0ea30991706b2b5,

title = "Electrostatic tweezer for droplet manipulation",

abstract = "Various physical tweezers for manipulating liquid droplets based on optical, electrical, magnetic, acoustic, or other external fields have emerged and revolutionized research and application in medical, biological, and environmental fields. Despite notable progress, the existing modalities for droplet control and manipulation are still limited by the extra responsive additives and relatively poor controllability in terms of droplet motion behaviors, such as distance, velocity, and direction. Herein, we report a versatile droplet electrostatic tweezer (DEST) for remotely and programmatically trapping or guiding the liquid droplets under diverse conditions, such as in open and closed spaces and on flat and tilted surfaces as well as in oil medium. DEST, leveraging on the coulomb attraction force resulting from its electrostatic induction to a droplet, could manipulate droplets of various compositions, volumes, and arrays on various substrates, offering a potential platform for a series of applications, such as high-throughput surface-enhanced Raman spectroscopy detection with single measuring time less than 20 s.",

keywords = "Droplet manipulation, Electrostatic induction, SERS, Tweezer",

author = "Yuankai Jin and Wanghuai Xu and Huanhuan Zhang and Ruirui Li and Jing Sun and Siyan Yang and Minjie Liu and Haiyang Mao and Zuankai Wang",

note = "Funding Information: 10. R. S. Hale, V. Bahadur, Electrowetting-based microfluidic operations on rapid-manufactured devices for heat pipe applications. J. Micromech. Microeng. 27, 075004 (2017). Materials and Methods Sample Preparation. 1H,1H,2H,2H-perfluorodecanethiol (97%; Sigma-Aldrich), perfluorooctanoic acid (95%; Sigma-Aldrich), glycerol (99.0%; Sigma-Aldrich), MG (J&K), R6G (J&K), and salts purchased from Sigma-Aldrich, including NaCl, NaClO2, NaOH, Na3PO4·12H2O, FeCl3, KSCN, and AgNO3, were used without further purification. The nanograss structure of copper oxide was obtained by chemically etching the cleaned copper in a hot (96 °C) alkaline solution including NaClO2, NaOH, Na3PO4·12H2O, and deionized water (at 3.75:5:10:100 wt ratio) for 15 min. Then, the immersion of copper oxide in a 0.5 mM 1H,1H,2H,2H-perfluor-ooctanethiol ethanol solution for 2 h could make the copper oxide superhy-drophobic. The superhydrophobic alumina substrates were obtained by successively immersing the cleaned aluminum in a 2.5 M HCl solution for 15 min, hot water (100 °C) for 5 min, and a 0.01 M perfluorooctanoic acid aqueous solution for 1 h. To render ITO-coated glass, polystyrene, gold-coated polystyrene, and other substrates superhydrophobic, these substrates were first sprayed using a commercial superhydrophobic sprayer, Glaco (purchased from Soft99 Corporation), followed by heating at 60°C for 5 min. The SERS surface was prepared using the combined candle soot and thin-film deposition processes (42). Briefly, a candle soot layer was first formed by placing a newly prepared glass above a burning candle flame for 15 s. Then, the candle soot–coated substrate was deposited by a thin parylene C film (∼150 nm) using specialized vacuum deposition equipment (Specialty Coating Systems, Inc.) as well as a thin silver film (∼30 nm) composed of nanoparticles using a vacuum sputter coating apparatus (Denton Vacuum LLC). Instrument and Characterization. The induced charges in droplets were measured using a Faraday cup connected to a nanocoulomb meter (Monroe; Model 284) using the method shown in SI Appendix, Fig. S2. The nanograss morphology of CuO was observed by a scanning electron microscope (Quan-taTM 450; FEG). The motion of the droplet, programmatically controlled by a stepper, was recorded by a high-speed camera (Fastcam SA4; Photron Limited) and analyzed using the software ImageJ. The gold coating on the polystyrene surface was coated with a dual-target sputtering system (Q150TS; Quorum). The electric conductivities of NaCl aqueous solution were directly measured by directly immersing the probe of the handy conductivity meter (LC-DDB-1M and CT-20; Lichen Tech.) into the solutions for 10 s. The static and dynamic contact angles of water droplets on superhydrophobic surfaces were measured by a Kruss DSA100 contact angle goniometer at ambient temperature, and the results are shown in SI Appendix, Table S1. Here, the dynamic contact angles (θa and θr) were measured by gradually increasing or decreasing the volume of droplets until the baseline of the droplet started to move. Data Availability. There are no data underlying this work. ACKNOWLEDGMENTS. We acknowledge financial support from National Natural Science Foundation of China Grant 31771083; Research Grants Council of Hong Kong Grants C1018-17G, 11275216, and 11218417; Shenzhen Science and Technology Innovation Council Grant JCYJ20170413141208098; and City University of Hong Kong Grants 9680212 and 9610375. We also appreciate the help of Dr. Dangyuan Lei and Dr. Siqi Li from City University of Hong Kong and Dr. Jiaqian Li from The University of Hong Kong. 11. W. Li et al., Supercapillary architecture-activated two-phase boundary layer struc-tures for highly stable and efficient flow boiling heat transfer. Adv. Mater. 32, e1905117 (2020). 12. Y. Zheng et al., Directional water collection on wetted spider silk. Nature 463, 640–643 (2010). 13. I. Oh et al., Enhanced condensation on liquid-infused nanoporous surfaces by vibration-assisted droplet sweeping. ACS Nano 14, 13367–13379 (2020). 14. I. Barbulovic-Nad, H. Yang, P. S. Park, A. R. Wheeler, Digital microfluidics for cell-based assays. Lab Chip 8, 519–526 (2008). 15. A. C. Sun et al., A droplet microfluidic platform for high-throughput photochemical reaction discovery. Nat. Commun. 11, 1–6 (2020). 16. H. Li et al., Droplet precise self-splitting on patterned adhesive surfaces for simultaneous multidetection. Angew. Chem. Int. Ed. Engl. 59, 10535–10539 (2020). 17. R. Mukherjee, S. F. Ahmadi, H. Zhang, R. Qiao, J. B. Boreyko, Electrostatic jumping of frost. ACS Nano 15, 4669–4677 (2021). 18. J. B. Boreyko, C. P. Collier, Delayed frost growth on jumping-drop superhydrophobic surfaces. ACS Nano 7, 1618–1627 (2013). 19. A.Shastry,M.J.Case,K.F.Bo€hringer,Directingdropletsusingmicrostructuredsurfa-ces. Langmuir 22, 6161–6167 (2006). 20. M. K. Chaudhury, G. M. Whitesides, How to make water run uphill. Science 256, 1539–1541 (1992). Downloaded at Elsevier Science London on January 12, 2022 21. J. A. Lv et al., Photocontrol of fluid slugs in liquid crystal polymer microactuators. Nature 537, 179–184 (2016). 22. H. Geng et al., Sunlight-driven water transport via a reconfigurable pump. Angew. Chem. Int. Ed. Engl. 57, 15435–15440 (2018). 23. W. Li, X. Tang, L. Wang, Photopyroelectric microfluidics. Sci Adv. 6, eabc1693 (2020). 24. J. Vialetto et al., Magnetic actuation of drops and liquid marbles using a deform-able paramagnetic liquid substrate. Angew. Chem. Int. Ed. Engl. 56, 16565–16570 (2017). 25. J. Guo et al., Omni-liquid droplet manipulation platform. Adv. Mater. Interfaces 6, 1900653 (2019). 26. H. Dai et al., Controllable high-speed electrostatic manipulation of water droplets on a superhydrophobic surface. Adv. Mater. 31, e1905449 (2019). 27. Q. Sun et al., Surface charge printing for programmed droplet transport. Nat. Mater. 18, 936–941 (2019). 28. D. R. Link et al., Electric control of droplets in microfluidic devices. Angew. Chem. Int. Ed. Engl. 45, 2556–2560 (2006). 29. H. Mertaniemi et al., Superhydrophobic tracks for low-friction, guided transport of water droplets. Adv. Mater. 23, 2911–2914 (2011). 30. A. Li et al., Programmable droplet manipulation by a magnetic-actuated robot. Sci. Adv. 6, eaay5808 (2020). 31. Y. Zhao et al., Bioinspired multifunctional Janus particles for droplet manipulation. J. Am. Chem. Soc. 135, 54–57 (2013). 32. Y. Xiao et al., Moving droplets in 3D using light. Adv. Mater. 30, e1801821 (2018). 33. J. Li, N. S. Ha, T. Liu, R. M. van Dam, C. J. Kim, Ionic-surfactant-mediated electro-dewetting for digital microfluidics. Nature 572, 507–510 (2019). 34. J. Nie et al., Self-powered microfluidic transport system based on triboelectric nano-generator and electrowetting technique. ACS Nano 12, 1491–1499 (2018). APPLIED PHYSICAL SCIENCES 35. L. Zheng et al., Self-powered electrostatic actuation systems for manipulating the movement of both microfluid and solid objects by using triboelectric nanogenerator. Adv. Funct. Mater. 27, 1606408 (2017). 36. Encyclopedia Britannica Inc., {"}Electric polarization{"} in Encyclop{\ae}dia Britannica Online (Britannica, 2004). https://www.britannica.com/science/electric-polarization. Accessed 30 December 2021. 37. C. Heinert, R. M. Sankaran, D. J. Lacks, Electrostatic charge generation on material surfaces from the evaporation of liquids. J. Electrostat. 105, 103450 (2020). 38. J. Berthier, Micro-Drops and Digital Microfluidics (William Andrew, 2012). 39. A. Z. Stetten, D. S. Golovko, S. A. L. Weber, H. J. Butt, Slide electrification: Charging of surfaces by moving water drops. Soft Matter 15, 8667–8679 (2019). 40. D. Wu et al., High-performance unidirectional manipulation of microdroplets by hor-izontal vibration on Femtosecond laser-induced slant microwall arrays. Adv. Mater. 32, e2005039 (2020). 41. J. K. Lee, D. Samanta, H. G. Nam, R. N. Zare, Micrometer-sized water droplets induce spontaneous reduction. J. Am. Chem. Soc. 141, 10585–10589 (2019). 42. R. Li et al., Self-concentrated surface-enhanced Raman scattering-active droplet sen-sor with three-dimensional hot spots for highly sensitive molecular detection in com-plex liquid environments. ACS Sens. 5, 3420–3431 (2020). 43. H. Li et al., Bioinspired micropatterned superhydrophilic Au-areoles for surface-enhanced Raman scattering (SERS) trace detection. Adv. Funct. Mater. 28, 1800448 (2018). 44. F. De Angelis et al., Breaking the diffusion limit with super-hydrophobic delivery of molecules to plasmonic nanofocusing SERS structures. Nat. Photonics 5, 682–687 (2011). 45. S. Shin et al., A droplet-based high-throughput SERS platform on a droplet-guiding-track-engraved superhydrophobic substrate. Small 13, 1602865 (2017). Funding Information: ACKNOWLEDGMENTS. We acknowledge financial support from National Natural Science Foundation of China Grant 31771083; Research Grants Council of Hong Kong Grants C1018-17G, 11275216, and 11218417; Shenzhen Science and Technology Innovation Council Grant JCYJ20170413141208098; and City University of Hong Kong Grants 9680212 and 9610375. We also appreciate the help of Dr. Dangyuan Lei and Dr. Siqi Li from City University of Hong Kong and Dr. Jiaqian Li from The University of Hong Kong. Publisher Copyright: {\textcopyright} 2022 National Academy of Sciences. All rights reserved.",

year = "2022",

month = jan,

day = "11",

doi = "10.1073/pnas.2105459119",

language = "English",

volume = "119",

journal = "Proceedings of the National Academy of Sciences of the United States of America",

issn = "0027-8424",

publisher = "National Academy of Sciences",

number = "2",

}

TY - JOUR

T1 - Electrostatic tweezer for droplet manipulation

AU - Jin, Yuankai

AU - Xu, Wanghuai

AU - Zhang, Huanhuan

AU - Li, Ruirui

AU - Sun, Jing

AU - Yang, Siyan

AU - Liu, Minjie

AU - Mao, Haiyang

AU - Wang, Zuankai

N1 - Funding Information: 10. R. S. Hale, V. Bahadur, Electrowetting-based microfluidic operations on rapid-manufactured devices for heat pipe applications. J. Micromech. Microeng. 27, 075004 (2017). Materials and Methods Sample Preparation. 1H,1H,2H,2H-perfluorodecanethiol (97%; Sigma-Aldrich), perfluorooctanoic acid (95%; Sigma-Aldrich), glycerol (99.0%; Sigma-Aldrich), MG (J&K), R6G (J&K), and salts purchased from Sigma-Aldrich, including NaCl, NaClO2, NaOH, Na3PO4·12H2O, FeCl3, KSCN, and AgNO3, were used without further purification. The nanograss structure of copper oxide was obtained by chemically etching the cleaned copper in a hot (96 °C) alkaline solution including NaClO2, NaOH, Na3PO4·12H2O, and deionized water (at 3.75:5:10:100 wt ratio) for 15 min. Then, the immersion of copper oxide in a 0.5 mM 1H,1H,2H,2H-perfluor-ooctanethiol ethanol solution for 2 h could make the copper oxide superhy-drophobic. The superhydrophobic alumina substrates were obtained by successively immersing the cleaned aluminum in a 2.5 M HCl solution for 15 min, hot water (100 °C) for 5 min, and a 0.01 M perfluorooctanoic acid aqueous solution for 1 h. To render ITO-coated glass, polystyrene, gold-coated polystyrene, and other substrates superhydrophobic, these substrates were first sprayed using a commercial superhydrophobic sprayer, Glaco (purchased from Soft99 Corporation), followed by heating at 60°C for 5 min. The SERS surface was prepared using the combined candle soot and thin-film deposition processes (42). Briefly, a candle soot layer was first formed by placing a newly prepared glass above a burning candle flame for 15 s. Then, the candle soot–coated substrate was deposited by a thin parylene C film (∼150 nm) using specialized vacuum deposition equipment (Specialty Coating Systems, Inc.) as well as a thin silver film (∼30 nm) composed of nanoparticles using a vacuum sputter coating apparatus (Denton Vacuum LLC). Instrument and Characterization. The induced charges in droplets were measured using a Faraday cup connected to a nanocoulomb meter (Monroe; Model 284) using the method shown in SI Appendix, Fig. S2. The nanograss morphology of CuO was observed by a scanning electron microscope (Quan-taTM 450; FEG). The motion of the droplet, programmatically controlled by a stepper, was recorded by a high-speed camera (Fastcam SA4; Photron Limited) and analyzed using the software ImageJ. The gold coating on the polystyrene surface was coated with a dual-target sputtering system (Q150TS; Quorum). The electric conductivities of NaCl aqueous solution were directly measured by directly immersing the probe of the handy conductivity meter (LC-DDB-1M and CT-20; Lichen Tech.) into the solutions for 10 s. The static and dynamic contact angles of water droplets on superhydrophobic surfaces were measured by a Kruss DSA100 contact angle goniometer at ambient temperature, and the results are shown in SI Appendix, Table S1. Here, the dynamic contact angles (θa and θr) were measured by gradually increasing or decreasing the volume of droplets until the baseline of the droplet started to move. Data Availability. There are no data underlying this work. ACKNOWLEDGMENTS. We acknowledge financial support from National Natural Science Foundation of China Grant 31771083; Research Grants Council of Hong Kong Grants C1018-17G, 11275216, and 11218417; Shenzhen Science and Technology Innovation Council Grant JCYJ20170413141208098; and City University of Hong Kong Grants 9680212 and 9610375. We also appreciate the help of Dr. Dangyuan Lei and Dr. Siqi Li from City University of Hong Kong and Dr. Jiaqian Li from The University of Hong Kong. 11. W. Li et al., Supercapillary architecture-activated two-phase boundary layer struc-tures for highly stable and efficient flow boiling heat transfer. Adv. Mater. 32, e1905117 (2020). 12. Y. Zheng et al., Directional water collection on wetted spider silk. Nature 463, 640–643 (2010). 13. I. Oh et al., Enhanced condensation on liquid-infused nanoporous surfaces by vibration-assisted droplet sweeping. ACS Nano 14, 13367–13379 (2020). 14. I. Barbulovic-Nad, H. Yang, P. S. Park, A. R. Wheeler, Digital microfluidics for cell-based assays. Lab Chip 8, 519–526 (2008). 15. A. C. Sun et al., A droplet microfluidic platform for high-throughput photochemical reaction discovery. Nat. Commun. 11, 1–6 (2020). 16. H. Li et al., Droplet precise self-splitting on patterned adhesive surfaces for simultaneous multidetection. Angew. Chem. Int. Ed. Engl. 59, 10535–10539 (2020). 17. R. Mukherjee, S. F. Ahmadi, H. Zhang, R. Qiao, J. B. Boreyko, Electrostatic jumping of frost. ACS Nano 15, 4669–4677 (2021). 18. J. B. Boreyko, C. P. Collier, Delayed frost growth on jumping-drop superhydrophobic surfaces. ACS Nano 7, 1618–1627 (2013). 19. A.Shastry,M.J.Case,K.F.Bo€hringer,Directingdropletsusingmicrostructuredsurfa-ces. Langmuir 22, 6161–6167 (2006). 20. M. K. Chaudhury, G. M. Whitesides, How to make water run uphill. Science 256, 1539–1541 (1992). Downloaded at Elsevier Science London on January 12, 2022 21. J. A. Lv et al., Photocontrol of fluid slugs in liquid crystal polymer microactuators. Nature 537, 179–184 (2016). 22. H. Geng et al., Sunlight-driven water transport via a reconfigurable pump. Angew. Chem. Int. Ed. Engl. 57, 15435–15440 (2018). 23. W. Li, X. Tang, L. Wang, Photopyroelectric microfluidics. Sci Adv. 6, eabc1693 (2020). 24. J. Vialetto et al., Magnetic actuation of drops and liquid marbles using a deform-able paramagnetic liquid substrate. Angew. Chem. Int. Ed. Engl. 56, 16565–16570 (2017). 25. J. Guo et al., Omni-liquid droplet manipulation platform. Adv. Mater. Interfaces 6, 1900653 (2019). 26. H. Dai et al., Controllable high-speed electrostatic manipulation of water droplets on a superhydrophobic surface. Adv. Mater. 31, e1905449 (2019). 27. Q. Sun et al., Surface charge printing for programmed droplet transport. Nat. Mater. 18, 936–941 (2019). 28. D. R. Link et al., Electric control of droplets in microfluidic devices. Angew. Chem. Int. Ed. Engl. 45, 2556–2560 (2006). 29. H. Mertaniemi et al., Superhydrophobic tracks for low-friction, guided transport of water droplets. Adv. Mater. 23, 2911–2914 (2011). 30. A. Li et al., Programmable droplet manipulation by a magnetic-actuated robot. Sci. Adv. 6, eaay5808 (2020). 31. Y. Zhao et al., Bioinspired multifunctional Janus particles for droplet manipulation. J. Am. Chem. Soc. 135, 54–57 (2013). 32. Y. Xiao et al., Moving droplets in 3D using light. Adv. Mater. 30, e1801821 (2018). 33. J. Li, N. S. Ha, T. Liu, R. M. van Dam, C. J. Kim, Ionic-surfactant-mediated electro-dewetting for digital microfluidics. Nature 572, 507–510 (2019). 34. J. Nie et al., Self-powered microfluidic transport system based on triboelectric nano-generator and electrowetting technique. ACS Nano 12, 1491–1499 (2018). APPLIED PHYSICAL SCIENCES 35. L. Zheng et al., Self-powered electrostatic actuation systems for manipulating the movement of both microfluid and solid objects by using triboelectric nanogenerator. Adv. Funct. Mater. 27, 1606408 (2017). 36. Encyclopedia Britannica Inc., "Electric polarization" in Encyclopædia Britannica Online (Britannica, 2004). https://www.britannica.com/science/electric-polarization. Accessed 30 December 2021. 37. C. Heinert, R. M. Sankaran, D. J. Lacks, Electrostatic charge generation on material surfaces from the evaporation of liquids. J. Electrostat. 105, 103450 (2020). 38. J. Berthier, Micro-Drops and Digital Microfluidics (William Andrew, 2012). 39. A. Z. Stetten, D. S. Golovko, S. A. L. Weber, H. J. Butt, Slide electrification: Charging of surfaces by moving water drops. Soft Matter 15, 8667–8679 (2019). 40. D. Wu et al., High-performance unidirectional manipulation of microdroplets by hor-izontal vibration on Femtosecond laser-induced slant microwall arrays. Adv. Mater. 32, e2005039 (2020). 41. J. K. Lee, D. Samanta, H. G. Nam, R. N. Zare, Micrometer-sized water droplets induce spontaneous reduction. J. Am. Chem. Soc. 141, 10585–10589 (2019). 42. R. Li et al., Self-concentrated surface-enhanced Raman scattering-active droplet sen-sor with three-dimensional hot spots for highly sensitive molecular detection in com-plex liquid environments. ACS Sens. 5, 3420–3431 (2020). 43. H. Li et al., Bioinspired micropatterned superhydrophilic Au-areoles for surface-enhanced Raman scattering (SERS) trace detection. Adv. Funct. Mater. 28, 1800448 (2018). 44. F. De Angelis et al., Breaking the diffusion limit with super-hydrophobic delivery of molecules to plasmonic nanofocusing SERS structures. Nat. Photonics 5, 682–687 (2011). 45. S. Shin et al., A droplet-based high-throughput SERS platform on a droplet-guiding-track-engraved superhydrophobic substrate. Small 13, 1602865 (2017). Funding Information: ACKNOWLEDGMENTS. We acknowledge financial support from National Natural Science Foundation of China Grant 31771083; Research Grants Council of Hong Kong Grants C1018-17G, 11275216, and 11218417; Shenzhen Science and Technology Innovation Council Grant JCYJ20170413141208098; and City University of Hong Kong Grants 9680212 and 9610375. We also appreciate the help of Dr. Dangyuan Lei and Dr. Siqi Li from City University of Hong Kong and Dr. Jiaqian Li from The University of Hong Kong. Publisher Copyright: © 2022 National Academy of Sciences. All rights reserved.

PY - 2022/1/11

Y1 - 2022/1/11

N2 - Various physical tweezers for manipulating liquid droplets based on optical, electrical, magnetic, acoustic, or other external fields have emerged and revolutionized research and application in medical, biological, and environmental fields. Despite notable progress, the existing modalities for droplet control and manipulation are still limited by the extra responsive additives and relatively poor controllability in terms of droplet motion behaviors, such as distance, velocity, and direction. Herein, we report a versatile droplet electrostatic tweezer (DEST) for remotely and programmatically trapping or guiding the liquid droplets under diverse conditions, such as in open and closed spaces and on flat and tilted surfaces as well as in oil medium. DEST, leveraging on the coulomb attraction force resulting from its electrostatic induction to a droplet, could manipulate droplets of various compositions, volumes, and arrays on various substrates, offering a potential platform for a series of applications, such as high-throughput surface-enhanced Raman spectroscopy detection with single measuring time less than 20 s.

AB - Various physical tweezers for manipulating liquid droplets based on optical, electrical, magnetic, acoustic, or other external fields have emerged and revolutionized research and application in medical, biological, and environmental fields. Despite notable progress, the existing modalities for droplet control and manipulation are still limited by the extra responsive additives and relatively poor controllability in terms of droplet motion behaviors, such as distance, velocity, and direction. Herein, we report a versatile droplet electrostatic tweezer (DEST) for remotely and programmatically trapping or guiding the liquid droplets under diverse conditions, such as in open and closed spaces and on flat and tilted surfaces as well as in oil medium. DEST, leveraging on the coulomb attraction force resulting from its electrostatic induction to a droplet, could manipulate droplets of various compositions, volumes, and arrays on various substrates, offering a potential platform for a series of applications, such as high-throughput surface-enhanced Raman spectroscopy detection with single measuring time less than 20 s.

KW - Droplet manipulation

KW - Electrostatic induction

KW - SERS

KW - Tweezer

UR - http://www.scopus.com/inward/record.url?scp=85122709690&partnerID=8YFLogxK

U2 - 10.1073/pnas.2105459119

DO - 10.1073/pnas.2105459119

M3 - Journal article

C2 - 34992136

AN - SCOPUS:85122709690

SN - 0027-8424

VL - 119

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

IS - 2

M1 - e2105459119

ER -

Electrostatic tweezer for droplet manipulation

Abstract

Keywords

ASJC Scopus subject areas

More information

Other files and links

Fingerprint

Cite this