Human mesenchymal stem cell form protrusions due to the ability to exploit the molecular mobility of the sliding hydrogel to rearrange the ligands and crosslinks.
Tong, X.; Yang, F., Sliding Hydrogels with Mobile Molecular Ligands and Crosslinks as 3D Stem Cell Niche. Advanced Materials, 2016, 28 (33), 7257-63.
PEG-based interpenetrating network (IPN), composed of two polymer networks, allows independent tuning on biochemical and mechanical properties.
Tong, X. and Yang, F., Engineering interpenetrating network hydrogels as biomimetic cell niche with independently tunable biochemical and mechanical properties. Biomaterials, 2014. 35(6): 1807-1815.
Monomer-level control on vinyl copolymers, an ATRA based strategy. In each cycle, one allyl alcohol is added to the ATRP chain end, and then the hydroxymethyl residue is oxidized to carboxylic acid and a side group is introduced via esterification, making the new chain end active for the next cycle.
Tong, X.M., Guo, B.H., and Huang, Y., Toward the synthesis of sequence-controlled vinyl copolymers. Chemical Communications, 2011. 47(5): 1455-1457.
Capping the alpha-cyclodextrin on poly(ethylene glycol) chains with comb shaped polycaprolactone enabled this polyrotaxane to be fabricated into film and self-assemble into nano particles.
Tong, X.; Zhang, X.; Ye, L.; Zhang, A.; Feng, Z., Synthesis and characterization of block copolymers comprising a polyrotaxane middle block flanked by two brush-like PCL blocks. Soft Matter, 2009. 5(9): 1848-1855.