TY - JOUR
T1 - Upper critical solution temperature thermo-responsive polymer brushes and a mechanism for controlled cell attachment
AU - Xue, Xuan
AU - Thiagarajan, Lalitha
AU - Braim, Shwana
AU - Saunders, Brian R.
AU - Shakesheff, Kevin M.
AU - Alexander, Cameron
N1 - Publisher Copyright:
© 2017 The Royal Society of Chemistry.
PY - 2017
Y1 - 2017
N2 - We report the synthesis of thermo-responsive polymer brushes with Upper Critical Solution Temperature (UCST)-type behaviour on glass to provide a new means to control cell attachment. Thermoresponsive poly(N-acryloyl glycinamide)-stat-poly(N-phenylacrylamide) (PNAGAm-PNPhAm) brushes with three different monomer ratios were synthesized to give tunable phase transition temperatures (Tp) in solution. Surface energies of surface-grafted brushes of these polymers at 25, 32, 37 and 50 °C were calculated from contact angle measurements and atomic force microscopy (AFM) studies confirmed that these polymers were highly extended at temperatures close to Tp in physiologically-relevant media. Importantly, NIH-3T3 cells were attached on the collapsed PNAGAm-PNPhAm brush surface at 30 °C after 20 h incubation, while release of cells from the extended brushes was observed within 2 h after the culture temperature was switched to 37 °C. Furthermore, the changes in cell attachment followed changes in the Lewis base component of surface energy. The results indicate that, in contrast to the established paradigm of enhanced cell attachment to surfaces where polymers are above a Lower Critical Solution Temperature (LCST), these novel substrates enable detachment of cells from surfaces at temperatures above a UCST. In turn these responsive materials open new avenues for the use of polymer-modified surfaces to control cell attachment for applications in cell manufacture and regenerative medicine.
AB - We report the synthesis of thermo-responsive polymer brushes with Upper Critical Solution Temperature (UCST)-type behaviour on glass to provide a new means to control cell attachment. Thermoresponsive poly(N-acryloyl glycinamide)-stat-poly(N-phenylacrylamide) (PNAGAm-PNPhAm) brushes with three different monomer ratios were synthesized to give tunable phase transition temperatures (Tp) in solution. Surface energies of surface-grafted brushes of these polymers at 25, 32, 37 and 50 °C were calculated from contact angle measurements and atomic force microscopy (AFM) studies confirmed that these polymers were highly extended at temperatures close to Tp in physiologically-relevant media. Importantly, NIH-3T3 cells were attached on the collapsed PNAGAm-PNPhAm brush surface at 30 °C after 20 h incubation, while release of cells from the extended brushes was observed within 2 h after the culture temperature was switched to 37 °C. Furthermore, the changes in cell attachment followed changes in the Lewis base component of surface energy. The results indicate that, in contrast to the established paradigm of enhanced cell attachment to surfaces where polymers are above a Lower Critical Solution Temperature (LCST), these novel substrates enable detachment of cells from surfaces at temperatures above a UCST. In turn these responsive materials open new avenues for the use of polymer-modified surfaces to control cell attachment for applications in cell manufacture and regenerative medicine.
UR - http://www.scopus.com/inward/record.url?scp=85021685659&partnerID=8YFLogxK
U2 - 10.1039/c7tb00052a
DO - 10.1039/c7tb00052a
M3 - Article
C2 - 32264008
AN - SCOPUS:85021685659
SN - 2050-750X
VL - 5
SP - 4926
EP - 4933
JO - Journal of Materials Chemistry B
JF - Journal of Materials Chemistry B
IS - 25
ER -