3D freeform printing of nanocomposite hydrogels through in situ precipitation in reactive Viscous fluid

Shengyang Chen, Tae Sik Jang, Houwen Matthew Pan, Hyun Do Jung, Ming Wei Sia, Shuying Xie, Yao Hang, Seow Khoon Mark Chong, Dongan Wang, Juha Song

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

Composite hydrogels have gained great attention as three-dimensional (3D) printing biomaterials because of their enhanced intrinsic mechanical strength and bioactivity compared to pure hydrogels. In most conventional printing methods for composite hydrogels, particles are preloaded in ink before printing, which often reduces the printability of composite ink with little mechanical improvement due to poor particle-hydrogel interaction of physical mixing. In contrast, the in situ incorporation of nanoparticles into a hydrogel during 3D printing achieves uniform distribution of particles with remarkable mechanical reinforcement, while precursors dissolved in inks do not influence the printing process. Herein, we introduced a "printing in liquid" technique coupled with a hybridization process, which allows 3D freeform printing of nanoparticle-reinforced composite hydrogels. A  viscoplastic matrix for this printing system provides not only support for printed hydrogel filaments but also chemical reactants to induce various reactions in printed objects for in situ modification. Nanocomposite hydrogel scaffolds were successfully fabricated through this 3D freeform printing of hyaluronic acid (HAc)-alginate (Alg) hydrogel inks through a two-step crosslinking strategy. The first ionic crosslinking of Alg provided structural stability during printing, while the secondary crosslinking of photo-curable HAc improved the mechanical and physiological stability of the nanocomposite hydrogels. For in situ precipitation during 3D printing, phosphate ions were dissolved in the hydrogel ink and calcium ions were added to the viscoplastic matrix. The composite hydrogels demonstrated a significant improvement in mechanical strength, biostability, as well as biological performance compared to pure HAc. Moreover, the multi-material printing of composites with different calcium phosphate contents was achieved by adjusting the ionic concentration of inks. Our method greatly accelerates the 3D printing of various functional or hybridized materials with complex geometries through the design and modification of printing materials coupled with in situ post-printing functionalization and hybridization in reactive viscoplastic matrices.

Original languageEnglish
Pages (from-to)1-21
Number of pages21
JournalInternational Journal of Bioprinting
Volume6
Issue number2
DOIs
StatePublished - 2020

Bibliographical note

Funding Information:
all authors. This research was supported by Nanyang Technological University Start up grant, and A*STAR Advanced Manufacturing and Engineering Individual Research Grants grant A1983c0031 from A*STAR.

Publisher Copyright:
© 2020 Chen, et al.

Keywords

  • Hydrogels
  • In situ precipitation
  • Multi-materials
  • Nanocomposites
  • Three-dimensional freeform printing
  • Viscous fluid matrix

Fingerprint

Dive into the research topics of '3D freeform printing of nanocomposite hydrogels through in situ precipitation in reactive Viscous fluid'. Together they form a unique fingerprint.

Cite this