Macromolecular Research

, Volume 26, Issue 12, pp 1143–1149 | Cite as

Interfacial Compression-Dependent Merging of Two Miscible Microdroplets in an Asymmetric Cross-Junction for In Situ Microgel Formation

  • Yeongseok Jang
  • Chaenyung Cha
  • Jinmu JungEmail author
  • Jonghyun OhEmail author


Controlling the merging of different microdroplets in a microfluidics system could generate a multitude of complex droplets because of their inherent surface tension, but poses a significant challenge because of their high surface tension. Here, a novel microfluidic merging technique is introduced using an asymmetric cross-junction geometry which increases the interfacial compression between two microdroplets. Microdroplets of two viscous polymer solutions, oxidized dextran (ODX) and N-carboxyethyl chitosan (N-CEC), which can undergo a crosslinking reaction via Schiff base formation, are allowed to merge at the asymmetric cross-junction without the assistance of additional merging schemes. The N-CEC and ODX microdroplets being formed at their orifices contact at a more favorable position to overcome their interfacial tension through this asymmetric geometry, until the interfacial layer breaks and pushes the former (with higher viscosity) into the latter. On the other hand, a typical symmetric cross-junction geometry cannot induce merging, because of insufficient interfacial compression generated by direct collision between two droplets. The merged N-CEC and ODX droplets soon become completely homogeneous via diffusion, ultimately leading to in situ microgel formation. Changing the concentration of ODX further controls the crosslinking density of the microgels. In addition, the viability of cells encapsulated within the microgels is well maintained, demonstrating the biocompatibility of the entire process. Taken together, the microfluidic merging technique introduced here could be broadly applicable for engineering cell-encapsulated microgels for biomedical applications.


N-carboxyethyl chitosan oxidized dextran microgel droplet merging asymmetric cross-junction 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. (1).
    T. Thorsen, R. W. Roberts, F. H. Arnold, and S. R. Quake, Phys. Rev. Lett., 86, 4163 (2001).CrossRefGoogle Scholar
  2. (2).
    C. Cramer, P. Fischer, and E. J. Windhab, Chem. Eng. Sci., 59, 3045 (2004).CrossRefGoogle Scholar
  3. (3).
    S. L. Anna, N. Bontoux, and H. A. Stone, Appl. Phys. Lett., 82, 364 (2003).CrossRefGoogle Scholar
  4. (4).
    S. A. Nabavi, G. T. Vladisavljevic, and V. Manovic, Chem. Eng. J., 322, 140 (2017).CrossRefGoogle Scholar
  5. (5).
    H. F. Chan, S. Ma, J. Tian, and K. W. Leong, Nanoscale, 9, 3485 (2017).CrossRefGoogle Scholar
  6. (6).
    A. T. Tyowua, S. G. Yiase, and B. P. Binks, J. Colloid Interface Sci., 488, 127 (2017).CrossRefGoogle Scholar
  7. (7).
    Q. Zhang, S. Savagatrup, P. Kaplonek, P. H. Seeberger, and T. M. Swager, ACS Cent. Sci., 3, 309 (2017).CrossRefGoogle Scholar
  8. (8).
    S. Seiffert, M. B. Romanowsky, and D. A. Weitz, Langmuir, 26, 14842 (2010).CrossRefGoogle Scholar
  9. (9).
    S. Y. Teh, R. Lin, L. H. Hung, and A. P. Lee, Lab Chip, 8, 198 (2008).CrossRefGoogle Scholar
  10. (10).
    M. Sun, S. S. Bithi, and S. A. Vanapalli, Lab Chip, 11, 3949 (2011).CrossRefGoogle Scholar
  11. (11).
    Y. C. Tan, Y. L. Ho, and A. P. Lee, Microfluid. Nanofluid., 3, 495 (2007).CrossRefGoogle Scholar
  12. (12).
    C. H. Yang, Y. S. Lin, K. S. Huang, Y. C. Huang, E. C. Wang, J. Y. Jhong, and C. Y. Kuo, Lab Chip, 9, 145 (2009).CrossRefGoogle Scholar
  13. (13).
    K. Liu, H. J. Ding, Y. Chen, and X. Z. Zhao, Microfluid. Nanofluid., 3, 239 (2007).CrossRefGoogle Scholar
  14. (14).
    N. Bremond, A. R. Thiam, and J. Bibette, Phys. Rev. Lett., 100, 024501 (2008).CrossRefGoogle Scholar
  15. (15).
    B. C. Lin and Y. C. Su, J. Micromech. Microeng., 18, 115005 (2008).CrossRefGoogle Scholar
  16. (16).
    D. R. Link, S. L. Anna, D. A. Weitz, and H. A. Stone, Phys. Rev. Lett., 92, 054503 (2004).CrossRefGoogle Scholar
  17. (17).
    Y. C. Tan, J. S. Fisher, A. I. Lee, V. Cristini, and A. P. Lee, Lab Chip, 4, 292 (2004).CrossRefGoogle Scholar
  18. (18).
    H. Sato, H. Matsumura, S. Keino, and S. Shoji, J. Micromech. Microeng., 16, 2318 (2006).CrossRefGoogle Scholar
  19. (19).
    B. Ziaie, A. Baldi, M. Lei, Y. Gu, and R. A. Siegel, Adv. Drug Deliv. Rev., 56, 145 (2004).CrossRefGoogle Scholar
  20. (20).
    S. Kim, J. Oh, and C. Cha, Colloids Surf. B Biointerfaces, 147, 1 (2016).CrossRefGoogle Scholar
  21. (21).
    P. C. Gach, K. Iwai, P. W. Kim, N. J. Hillson, and A. K. Singh, Lab Chip, 17, 3388 (2017).CrossRefGoogle Scholar
  22. (22).
    E. Um and J. K. Park, Lab Chip, 9, 207 (2009).CrossRefGoogle Scholar
  23. (23).
    G. F. Christopher, J. Bergstein, N. B. End, M. Poon, C. Nguyen, and S. L. Anna, Lab Chip, 9, 1102 (2009).CrossRefGoogle Scholar
  24. (24).
    Y. C. Tan, Y. L. Ho, and A. P. Lee, Microfluid. Nanofluid., 3, 495 (2007).CrossRefGoogle Scholar
  25. (25).
    S. Okushima, T. Nisisako, T. Torii, and T. Higuchi, Langmuir, 20, 9905 (2004).CrossRefGoogle Scholar
  26. (26).
    L. Y. Chu, A. S. Utada, R. K. Shah, J. W. Kim, and D. A. Weitz, Angew. Chem. Int. Ed., 46, 8970 (2007).CrossRefGoogle Scholar
  27. (27).
    V. Chokkalingam, B. Weidenhof, M. Krämer, S. Herminghaus, R. Seemann, and W. F. Maier, ChemPhysChem, 11, 2091 (2010).CrossRefGoogle Scholar
  28. (28).
    V. Chokkalingam, B. Weidenhof, M. Krämer, W. F. Maier, S. Herminghaus, and R. Seemann, Lab Chip, 10, 1700 (2010).CrossRefGoogle Scholar
  29. (29).
    B. J. Jin, Y. W. Kim, Y. Lee, and J. Y. Yoo, J. Micromech. Microeng., 20, 035003 (2010).CrossRefGoogle Scholar
  30. (30).
    L. M. Fidalgo, C. Abell, and W. T. Huck, Lab Chip, 7, 984 (2007).CrossRefGoogle Scholar
  31. (31).
    X. Niu, S. Gulati, J. B. Edel, and A. J. deMello, Lab Chip, 8, 1837 (2008).CrossRefGoogle Scholar
  32. (32).
    J. Sivasamy, Y. C. Chim, T. N. Wong, N. T. Nguyen, and L. Yobas, Microfluid. Nanofluid., 8, 409 (2010).CrossRefGoogle Scholar
  33. (33).
    H. Gu, M. H. G. Duits, and F. Mugele, Int. J. Mol. Sci., 12, 2572 (2011).CrossRefGoogle Scholar
  34. (34).
    M. Lee, J. W. Collins, D. M. Aubrecht, R. A. Sperling, L. Solomon, J. W. Ha, G. R. Yi, D. A. Weitz, and V. N. Manoharan, Lab Chip, 14, 509 (2014).CrossRefGoogle Scholar
  35. (35).
    M. Zagnoni and J. M. Cooper, Lab Chip, 9, 2652 (2009).CrossRefGoogle Scholar
  36. (36).
    A. R. Guzman, H. S. Kim, P. de Figueiredo, and A. Han, Biomed. Microdevices, 17, 35 (2015).CrossRefGoogle Scholar
  37. (37).
    V. B. Varma, A. Ray, Z. M. Wang, Z. P. Wang, and R. V. Ramanujan, Sci. Rep., 6, 37671 (2016).CrossRefGoogle Scholar
  38. (38).
    J. Jung, K. Kim, S. C. Choi, and J. Oh, Biotechnol. Lett., 36, 1549 (2014).CrossRefGoogle Scholar
  39. (39).
    L. Weng, A. Romanov, J. Rooney, and W. Chen, Biomaterials, 29, 3905 (2008).CrossRefGoogle Scholar
  40. (40).
    J. Jung and J. Oh, Biomicrofluidics, 8, 036503 (2014).CrossRefGoogle Scholar
  41. (41).
    J. Oh, K. Kim, S. Choi, and J. Jung, Dig. J. Nanomater. Biostruct., 9, 739 (2014).Google Scholar
  42. (42).
    J. D. Tice, H. Song, A. D. Lyon, and R. F. Ismagilov, Langmuir, 19, 9127 (2003).CrossRefGoogle Scholar
  43. (43).
    J. D. Berry, M. J. Neeson, R. R. Dagastine, D. Y. C. Chan, and R. F. Tabor, J. Colloid Interface Sci., 454, 226 (2015).CrossRefGoogle Scholar
  44. (44).
    S. Fordham, Proc. Royal Soc. A, 194, 1 (1948).Google Scholar

Copyright information

© The Polymer Society of Korea and Springer Nature B.V. 2018

Authors and Affiliations

  1. 1.Department of Mechanical Design Engineering, College of EngineeringChonbuk National UniversityJeonju, JeonbukKorea
  2. 2.School of Materials Science and EngineeringUlsan National Institute of Science and Technology (UNIST)UlsanKorea
  3. 3.Department of Nano-bio Mechanical System Engineering, College of EngineeringChonbuk National UniversityJeonju, JeonbukKorea

Personalised recommendations