CO₂-Triggered ON/OFF Wettability Switching on Bioinspired Polylactic Acid Porous Films for Controllable Bioadhesion

Abstract

Bioinspired honeycomb-like porous films with switchable properties have drawn much attention recently owing to their potential application in scenarios in which the conversion between two opposite properties is required. Herein, the CO 2 -gastriggered ON/OFF switching wettability of biocompatible polylactic acid (PLA) honeycomb porous films is fabricated. Highly ordered porous films with diameters between 2.0 and 2.8 μm are separately prepared from complexes of nonresponsive PLA and a CO 2 -sensitive melamine derivative [N 2 ,N 4 ,N 6 -tris(3-(dimethylamino)propyl)-1,3,5-triazine-2,4,6-triamine, MET] via the breath figure method. The hydrophilic CO 2 -sensitive groups can be precisely arranged in the pore's inner surface and/or top surface of the films by simply changing the PLA/MET ratio. The sensitive groups in the pore's inner surface act as a switch triggered by CO 2 gas controlling water to enter the pores or not, thus resulting in ON/OFF switching wettability. The largest response of the water contact angle of honeycomb films reaches 35°, from 100 to 65°, leading to an obvious hydrophobic−hydrophilic conversion. The improved surface wettability enhances the interaction between the cell and honeycomb film surface, thus resulting in a better cell attachment. Such smart properties accompanying the biocompatible polymer and biological gas trigger facilitate possible biomedical and bioengineering applications in the future for these films.

Effect of polar groups of polystyrenes on the self‐assembly of breath figure arrays

“…Since the first report of condensing droplets by Lord Rayleigh in 1911, 17 the BF method uses volatile solvents to induce vapor condensation, leaving porous imprints after the total evaporation of solvents and droplets. The stability of water droplets and their rearrangement by Marangoni convection and thermocapillary force ensure the formation of honeycomb patterns 18–31 …”

“…The stability of water droplets and their rearrangement by Marangoni convection and thermocapillary force ensure the formation of honeycomb patterns. [18][19][20][21][22][23][24][25][26][27][28][29][30][31] Up to now, a lot of polymers with different topological structures have been investigated in the BF process, including star-shaped polymers, 18,32,33 dendrimers, 34 comb-like polymers, 35 rod-coil block copolymers, 36,37 and linear polymers. [38][39][40][41][42][43] Apart from topology, the chemical composition of polymers also shows great impact on their self-assembly behavior.…”

Modified Breath Figure Methods for the Pore-Selective Functionalization of Honeycomb-Patterned Porous Polymer Films

“…Highly-ordered patterned porous films mimicking natural honeycomb structures have attracted much research interest because of their ordered porosity, lightweight, stretchability, mechanical strength, and high surface area [ 1 , 2 , 3 ]. These properties make them highly desirable for potential applications such as antibacterial membranes [ 4 , 5 ], microelectronics [ 6 ], sensors [ 7 , 8 , 9 , 10 , 11 ], cell culture scaffolds [ 12 , 13 ], superhydrophobic surfaces [ 14 , 15 ], and size-selective separators [ 16 ]. These films can be obtained either via top-down lithographic techniques, such as photo-lithography [ 17 ] and contact lithography, or bottom-up fabrication such as self-assembly mechanisms of colloidal particles [ 18 , 19 ], emulsions [ 20 , 21 ], block copolymers [ 22 , 23 ], and phase separation [ 24 , 25 ].…”

Effect of Pore Size of Honeycomb‐Patterned Polymer Film on Spontaneous Formation of 2D Micronetworks by Coculture of Human Umbilical Vein Endothelial Cells and Mesenchymal Stem Cells

“…[ 31 ] Furthermore, some research groups have reported that HCF has potential as a promising cell culture scaffold. [ 32–35 ]…”