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Continuous, autonomous subsurface cargo shuttling by nature-inspired meniscus-climbing systems

Nature Chemistry volume 14, pages 208–215 (2022)Cite this article

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Abstract

Water-walking insects can harness capillary forces by changing their body posture to climb or descend the meniscus between the surface of water and a solid object. Controlling surface tension in this manner is necessary for predation, escape and survival. Inspired by this behaviour, we demonstrate autonomous, aqueous-based synthetic systems that overcome the meniscus barrier and shuttle cargo subsurface to and from a landing site and a targeted drop-off site. We change the sign of the contact angle of a coacervate sac containing an aqueous phase or of a hydrogel droplet hanging from the surface by controlling the normal force acting on the sac or droplet. The cyclic buoyancy-induced cargo shuttling occurs continuously, as long as the supply of reactants diffusing to the sac or droplet from the surrounding aqueous phase is not exhausted. These findings may lead to potential applications in autonomously driven reaction or delivery systems and micro-/milli-robotics.

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Fig. 1: Schematics of systems found in nature and nature-inspired meniscus-climbing systems.
Fig. 2: Meniscus-climbing droplets with different behaviour.
Fig. 3: Switchable meniscus-climbing behaviour of the aqueous droplet under salt environments.
Fig. 4: Autonomous and reversible meniscus-climbing behaviour by catalase-functionalized synthetic systems.
Fig. 5: Material shuttle and transport of the nature-inspired meniscus-climbing system driven by density difference and magnetic force.
Fig. 6: Autonomous and continuous material shuttle and transport of the nature-inspired meniscus-climbing system driven by buoyancy force from bubbles.

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All relevant data generated or analysed for this study are included in the article and its Supplementary Information files. Source data are provided with this paper.

References

  1. Bush, J. W. M. & Hu, D. L. Walking on water: biolocomotion at the Interface. Annu. Rev. Fluid. Mech. 38, 339–369 (2006).

    Article  Google Scholar 

  2. Hu, D. L. & Bush, J. W. Meniscus-climbing insects. Nature 437, 733–736 (2005).

    Article  CAS  Google Scholar 

  3. Bush, J. W. M., Hu, D. L. & Prakash, M. The integument of water-walking arthropods: form and function. Adv. Insect. Physiol 34, 117–192 (2007).

    Article  Google Scholar 

  4. Jiang, L. et al. ‘Water strider’ legs with a self-assembled coating of single-crystalline nanowires of an organic semiconductor. Adv. Mater. 22, 376–379 (2010).

    Article  CAS  Google Scholar 

  5. Wang, Q., Yao, X., Liu, H., Quéré, D. & Jiang, L. Self-removal of condensed water on the legs of water striders. Proc. Natl Acad. Sci. USA 112, 9247–9252 (2015).

    Article  CAS  Google Scholar 

  6. Gao, X. & Jiang, L. Water-repellent legs of water striders. Nature 432, 36–36 (2004).

    Article  CAS  Google Scholar 

  7. Lee, S. C., Kim, J. H. & Lee, S. J. Floating of the lobes of mosquito (Aedes togoi) larva for respiration. Sci. Rep. 7, 43050–43050 (2017).

    Article  CAS  Google Scholar 

  8. Chan, D. Y. C., Henry, J. D. & White, L. R. The interaction of colloidal particles collected at fluid interfaces. J. Colloid Interf. Sci 79, 410–418 (1981).

    Article  CAS  Google Scholar 

  9. Jiang, J. et al. Directional pumping of water and oil microdroplets on slippery surface. Proc. Natl Acad. Sci. USA 116, 2482–2487 (2019).

    Article  CAS  Google Scholar 

  10. Hara, Y., Saiki, M., Suzuki, T. & Kikuchi, K. A meniscus-climbing gel robot. Chem. Lett. 43, 938–940 (2014).

    Article  CAS  Google Scholar 

  11. Hu, D. L., Prakash, M., Chan, B. & Bush, J. W. M. Water-walking devices. Exp. Fluids 43, 769–778 (2007).

    Article  Google Scholar 

  12. Xie, G. et al. Compartmentalized, all-aqueous flow-through-coordinated reaction systems. Chem 5, 2678–2690 (2019).

    Article  CAS  Google Scholar 

  13. Tavana, H. et al. Nanolitre liquid patterning in aqueous environments for spatially defined reagent delivery to mammalian cells. Nat. Mater. 8, 736–741 (2009).

    Article  CAS  Google Scholar 

  14. Zhang, L. et al. One-step microfluidic fabrication of polyelectrolyte microcapsules in aqueous conditions for protein release. Angew. Chem. Int. Ed. 55, 13470–13474 (2016).

    Article  CAS  Google Scholar 

  15. Liu, Q., Yuan, Z., Guo, X. & van Esch, J. H. Dual-functionalized crescent microgels for selectively capturing and killing cancer cells. Angew. Chem. Int. Ed. 59, 14076–14080 (2020).

    Article  CAS  Google Scholar 

  16. Liu, Q. et al. Self-orienting hydrogel micro-buckets as novel cell carriers. Angew. Chem. Int. Ed. 58, 547–551 (2019).

    Article  CAS  Google Scholar 

  17. Xie, G. et al. Hanging droplets from liquid surfaces. Proc. Natl Acad. Sci. USA 117, 8360–8365 (2020).

    Article  CAS  Google Scholar 

  18. Hann, S. D., Niepa, T. H., Stebe, K. J. & Lee, D. One-step generation of cell-encapsulating compartments via polyelectrolyte complexation in an aqueous two phase system. ACS Appl. Mater. Interfaces 8, 25603–25611 (2016).

    Article  CAS  Google Scholar 

  19. Hann, S. D., Stebe, K. J. & Lee, D. AWE-somes: all water emulsion bodies with permeable shells and selective compartments. ACS Appl. Mater. Interfaces 9, 25023–25028 (2017).

    Article  CAS  Google Scholar 

  20. Huang, X. et al. Bioinspired robust all-aqueous droplet via diffusion-controlled interfacial coacervation. Adv. Funct. Mater. 30, 2004166 (2020).

  21. Chao, Y. & Shum, H. C. Emerging aqueous two-phase systems: from fundamentals of interfaces to biomedical applications. Chem. Soc. Rev. 49, 114–142 (2020).

    Article  CAS  Google Scholar 

  22. Albertsson, P. E. R. Å. Partition of proteins in liquid polymer–polymer two-phase systems. Nature 182, 709–711 (1958).

    Article  CAS  Google Scholar 

  23. Zhu, S. et al. Rapid multilevel compartmentalization of stable all-aqueous blastosomes by interfacial aqueous-phase separation. ACS Nano 14, 11215–11224 (2020).

    Article  CAS  Google Scholar 

  24. Vella, D. & Mahadevan, L. The ‘Cheerios effect’. Am. J. Phys. 73, 817–825 (2005).

    Article  Google Scholar 

  25. Vella, D. Floating versus sinking. Annu. Rev. Fluid. Mech. 47, 115–135 (2015).

    Article  Google Scholar 

  26. Kumar, B., Patil, A. J. & Mann, S. Enzyme-powered motility in buoyant organoclay/DNA protocells. Nat. Chem. 10, 1154–1163 (2018).

    Article  CAS  Google Scholar 

  27. Solovev, A. A., Mei, Y. & Schmidt, O. G. Catalytic microstrider at the air–liquid interface. Adv. Mater. 22, 4340–4344 (2010).

    Article  CAS  Google Scholar 

  28. Adams, L. L. A., Lee, D., Mei, Y., Weitz, D. A. & Solovev, A. A. Nanoparticle-shelled catalytic bubble micromotor. Adv. Mater. Interfaces 7, 1901583 (2020).

    Article  CAS  Google Scholar 

  29. Tsai, S. S., Wexler, J. S., Wan, J. & Stone, H. A. Microfluidic ultralow interfacial tensiometry with magnetic particles. Lab Chip 13, 119–125 (2013).

    Article  CAS  Google Scholar 

  30. Hu, W., Lum, G. Z., Mastrangeli, M. & Sitti, M. Small-scale soft-bodied robot with multimodal locomotion. Nature 554, 81–85 (2018).

    Article  CAS  Google Scholar 

  31. Jones, A. M. & Knudsen, J. G. Drag coefficients at low Reynolds numbers for flow past immersed bodies. Aiche J 7, 20–25 (1961).

    Article  CAS  Google Scholar 

  32. Holyst, R. et al. Scaling form of viscosity at all length-scales in poly(ethylene glycol) solutions studied by fluorescence correlation spectroscopy and capillary electrophoresis. Phys. Chem. Chem. Phys. 11, 9025–9032 (2009).

    Article  CAS  Google Scholar 

  33. Pantarotto, D., Browne, W. R. & Feringa, B. L. Autonomous propulsion of carbon nanotubes powered by a multienzyme ensemble. Chem. Commun. 1533–1535 (2008).

Download references

Acknowledgements

The design, characterization, and analysis of the hanging droplets experiments were supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under contract number DE-AC02-05-CH11231 within the Adaptive Interfacial Assemblies Towards Structuring Liquids program (KCTR16) (G.X., P.Y.K., B.A.H., P.D.A. and T.P.R.). We also acknowledge the use of the Molecular Foundry which is supported by the Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under the same contract. Transport and assembly studies were supported by the Army Research Office under contract W911NF-20-0093 (G.X. and T.P.R.).

Author information

Authors and Affiliations

  1. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

    Ganhua Xie, Pei Li, Paul Y. Kim, Pei-Yang Gu, Brett A. Helms, Paul D. Ashby & Thomas P. Russell

  2. Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China

    Pei Li & Lei Jiang

  3. College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation, Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, China

    Pei-Yang Gu

  4. The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

    Brett A. Helms & Paul D. Ashby

  5. Polymer Science and Engineering Department, Conte Center for Polymer Research, University of Massachusetts Amherst, Amherst, MA, USA

    Thomas P. Russell

  6. WPI–Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, Japan

    Thomas P. Russell

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  1. Ganhua Xie
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Contributions

G.X. and T.P.R. designed the experiments. G.X., P.L. and P.-Y.G. performed the experiments. G.X., P.Y.K., B.A.H., P.D.A., L.J. and T.P.R. discussed the results and analysis. G.X. and T.P.R. wrote the manuscript with input from all the coauthors.

Corresponding author

Correspondence to Thomas P. Russell.

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The authors declare no competing interests.

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Peer review information Nature Chemistry thanks Samuel Sanchez and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Description of Supplementary Videos, Materials, Figs. 1–18 and Table 1.

Supplementary Video 1

A droplet of 15 wt. % dextran solution containing 0.8 wt. % PDADMAC with a density ρdextan = 1.055 g ml–1 and diameter D = 2.98 mm was released from a height of h = 10 mm above the surface of 10 wt. % PEG aqueous solution with a lower density (ρPEG = 1.043 g ml–1) containing 1 wt. % PSS and 0.49 mol kg–1 NaCl. The droplet was broken into pieces with a tail-like structure hanging on the surface and other parts sinking into the bottom after impacting the surface of PEG solution.

Supplementary Video 2

Switchable meniscus-climbing behaviour of the aqueous dextran droplet on the surface of PEG solution containing 2.93 mol kg–1 NaCl from a side view. A droplet of 15 wt. % aqueous dextran solution containing 0.91 wt. % PAH with a diameter of 2.98 mm was released from a height of 10 mm to hit the surface of 10 wt. % aqueous PEG solution containing 2 wt. % PSS and 2.93 mol kg–1 NaCl in a cuvette (12.5 mm × 12.5 mm × 45 mm). After impacting the surface, the droplet experienced landing on the wall of the container, and then a slipping toward the surface centre of dextran solution.

Supplementary Video 3

Switchable meniscus-climbing behaviour of the aqueous dextran droplet on the surface of PEG solution containing 2.93 mol kg–1 NaCl from a top view. A droplet of 15 wt. % aqueous dextran solution containing 0.91 wt. % PAH with a diameter of 2.98 mm was released from a height of 10 mm to hit the surface of 10 wt. % aqueous PEG solution containing 2 wt. % PSS and 2.93 mol kg–1 NaCl in a glass microbeaker (12 mm Dia. x 13 mm Hgt.). After impacting the surface, the droplet experienced landing on the wall of the container, and then a slipping toward the centre of the surface of the dextran solution.

Supplementary Video 4

Switchable meniscus-climbing behaviour of the aqueous dextran droplet on the surface of PEG solution containing 1.22 mol kg–1 NaCl from a top view. A droplet of 15 wt. % aqueous dextran solution containing 0.91 wt. % PAH with a diameter of 2.98 mm was released from a height of 10 mm to hit the surface of 10 wt. % aqueous PEG solution containing 2 wt. % PSS and 1.22 mol kg–1 NaCl in a glass microbeaker (12 mm Dia. x 13 mm Hgt.). After impacting the surface, the droplet experienced landing on the wall of the container and slipping toward the surface centre of dextran solution. The maximum climbing distance of the droplet is smaller than that of the droplet in 2.93 mol kg–1 NaCl. Trace amount of FITC-labelled dextran was used to increase the contrast of the dextran droplet.

Supplementary Video 5

After hydrogen peroxide was added into the PEG solution (10 wt. % PEG, 5 mg mL–1 CaCl2, 0.75 wt. % H2O2, pH 5.51), oxygen bubbles were observed to be generated on the surface of the catalase-functionalized hydrogel dextran sac (15 wt. % dextran, 7.2 mg mL–1 SA, 1.6 mg mL–1 catalase, pH 6.01). Meniscus-climbing behaviour was observed but the sac failed to reach the wall of a plastic well with a diameter of 15.6 mm before the bubble released from the sac surface.

Supplementary Video 6

After hydrogen peroxide was added into the PEG solution (10 wt. % PEG, 5 mg mL–1 CaCl2, 3 wt. % H2O2, pH 6.04), oxygen bubbles were observed to be generated on the surface of the catalase-functionalized hydrogel dextran sac (15 wt. % dextran, 7.2 mg mL–1 SA, 1.6 mg mL–1 catalase, pH 6.01). Meniscus-climbing behaviour was observed but the sac failed to return to the surface centre of PEG solution in a plastic well with a diameter of 15.6 mm. The three-phase contact line around the sac was destroyed by the crowded bubbles.

Supplementary Video 7

Autonomous reversible meniscus-climbing behaviour by a hanging hydrogel sac functionalized with catalase (15 wt. % dextran, 7.2 mg mL–1 SA, 1.6 mg mL–1 catalase, pH 6.01). After hydrogen peroxide was added into the PEG solution (10 wt. % PEG, 5 mg mL–1 CaCl2, 1.5 wt. % H2O2, pH 5.42), the oxygen bubbles produced drive the sac to land on the wall of a plastic well with a diameter of 15.6 mm. When the bubbles released or burst, the sac returned to the surface centre of PEG solution. This process is completely reversible until the fuel is exhausted.

Supplementary Video 8

Switchable meniscus-climbing behaviour of the MMP-functionalized aqueous dextran droplet (15 wt. % dextran, 1.2 wt. % PDADMAC, 4–5.5 mg mL–1 MMP) in a container (12.5 mm × 12.5 mm × 45 mm) with hydrophilic walls (θ<90o) under a magnetic field. Applying a magnetic field (ON) causes the droplet to climb the meniscus at the hydrophilic wall. After removing the magnetic field (OFF), the droplet returned to the centre of the surface of the PEG solution (10 wt. %, 1.5 wt. % PSS). The process is reversible.

Supplementary Video 9

Switchable meniscus-climbing behaviour of the MMP-functionalized aqueous dextran droplet (15 wt. % dextran, 1.2 wt. % PDADMAC, 4–5.5 mg mL–1 MMP) in a container (12.5 mm × 12.5 mm × 45 mm) with hydrophobic walls (θ>90o) under a magnetic field. Applying a magnetic field (ON) induces the droplet to climb up to the top of the curved interface between a PEG solution (10 wt. %, 1.5 wt. % PSS) and an oil layer (silicone oil: 0.996 g mL–1) atop. After removing the magnetic field (OFF), the droplet returned to the hydrophobic walls of the container. The process is reversible.

Supplementary Video 10

Switchable meniscus-climbing behaviour of the MMP-functionalized aqueous dextran droplet (15 wt. % dextran, 1.2 wt. % PDADMAC, 4–5.5 mg mL–1 MMP) between a hydrophobic wall (θ > 90o) and a hydrophilic wall (θ < 90o) of a container (12.5 mm × 12.5 mm × 45 mm) under magnetic field. Applying a magnetic field (ON) induces the droplet to climb the slope upward to the hydrophilic wall. After removing the magnetic field (OFF), the droplet slips downward to the hydrophobic wall. The slope is formed by an interface between a PEG solution (10 wt. %, 1.5 wt. % PSS) and an oil layer (silicone oil: 0.996 g mL–1) atop. This process is reversible.

Supplementary Video 11

Autonomous and reversible material shuttle and transport by enzyme-functionalized synthetic systems. Catalase and ALP are functionalized into the hydrogel dextran sac (15 wt. % dextran, 7.2 mg mL–1 SA, 1.8 mg mL–1 catalase, 2 mg mL–1 ALP, pH 5.29). When hydrogen peroxide is added into the PEG phase (10 wt. % PEG, 5 mg mL–1 CaCl2, 1.5 wt. % H2O2, pH 5.42), the generated oxygen bubbles drive the hanging sac to climb the meniscus and dock on the hydrogel wall containing PPBP of a plastic well with a diameter of 15.6 mm. PPBP molecules diffuse into the sac and decomposed into phenolphthalein with a pink coloration and phosphates, which make the sac darker and darker. Simultaneously, continuous bubble release decreases the buoyant force on the sac, which start to return to the surface centre when the meniscus recovers to be negative. The shuttling and loading cycle repeats until hydrogen peroxide is exhausted.

Source data

Source Data Fig. 3

Statistical Source Data for Fig. 3c.

Source Data Fig. 4

Statistical Source Data for Fig. 4c.

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Xie, G., Li, P., Kim, P.Y. et al. Continuous, autonomous subsurface cargo shuttling by nature-inspired meniscus-climbing systems. Nat. Chem. 14, 208–215 (2022). https://doi.org/10.1038/s41557-021-00837-5

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