TY - JOUR
T1 - How protonation modulates the interaction between proteins and pH-responsive hydrogel films
AU - Longo, Gabriel S.
AU - Pérez-Chávez, Néstor A.
AU - Szleifer, Igal
N1 - Funding Information:
This work was supported by CONICET and ANPCyT ( PICT-2014-3377 , PICT-2017-3513 ), Argentina. N.A.P.-C. acknowledges a ANPCyT fellowship ( PICT-2015-3425 ). I.S. acknowledges support from NSF , Div. of Chem., Bioeng., Env., & Transp. Sys. 1833214 .
Funding Information:
This work was supported by CONICET and ANPCyT (PICT-2014-3377, PICT-2017-3513), Argentina. N.A.P.-C. acknowledges a ANPCyT fellowship (PICT-2015-3425). I.S. acknowledges support from NSF, Div. of Chem., Bioeng., Env., & Transp. Sys. 1833214.
Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2019/6
Y1 - 2019/6
N2 - Hydrogels of pH-responsive polymers are promising candidates for the design of functional biomaterials. In this context, understanding the complexity of the interaction between these materials and proteins is essential. A recently developed molecular-level equilibrium theory for protein adsorption on hydrogels of cross-linked polyacid chains allows for modeling size, shape, charge distribution, protonation state and conformational degrees of freedom of all chemical species in the system; proteins are described using a coarse-grained model of their crystallographic structure. This review summarizes our recent studies, which have focused on understanding how the interaction between proteins and pH-responsive hydrogel films depends on the pH and salt concentration, both in single protein solutions and mixtures. In particular, we discuss the key role that protonation plays in mediating the polymer-protein electrostatic attractions that drive adsorption. Deprotonation of the polyacid network modifies the nano-environment inside the hydrogel; the local pH drops inside the film. In single protein solutions, protonation of amino acid residues in this lower-pH environment favors adsorption to the hydrogel. Upon adsorption, the net charge of the protein can be several units more positive than in the solution. The various amino acids protonate differently, in a non-trivial way, which gives flexibility to the protein to enhance its positive charge and favor adsorption under a wide range of conditions. In binary and ternary protein solutions, amino acid protonation is the decisive factor for selective adsorption under certain conditions. We show that the polymer network composition and the solution pH can be used to separate and localize proteins within nanometer-sized regions.
AB - Hydrogels of pH-responsive polymers are promising candidates for the design of functional biomaterials. In this context, understanding the complexity of the interaction between these materials and proteins is essential. A recently developed molecular-level equilibrium theory for protein adsorption on hydrogels of cross-linked polyacid chains allows for modeling size, shape, charge distribution, protonation state and conformational degrees of freedom of all chemical species in the system; proteins are described using a coarse-grained model of their crystallographic structure. This review summarizes our recent studies, which have focused on understanding how the interaction between proteins and pH-responsive hydrogel films depends on the pH and salt concentration, both in single protein solutions and mixtures. In particular, we discuss the key role that protonation plays in mediating the polymer-protein electrostatic attractions that drive adsorption. Deprotonation of the polyacid network modifies the nano-environment inside the hydrogel; the local pH drops inside the film. In single protein solutions, protonation of amino acid residues in this lower-pH environment favors adsorption to the hydrogel. Upon adsorption, the net charge of the protein can be several units more positive than in the solution. The various amino acids protonate differently, in a non-trivial way, which gives flexibility to the protein to enhance its positive charge and favor adsorption under a wide range of conditions. In binary and ternary protein solutions, amino acid protonation is the decisive factor for selective adsorption under certain conditions. We show that the polymer network composition and the solution pH can be used to separate and localize proteins within nanometer-sized regions.
KW - Acid-base equilibrium
KW - Protein adsorption
KW - Protonation
KW - pH-responsive hydrogels
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U2 - 10.1016/j.cocis.2018.11.009
DO - 10.1016/j.cocis.2018.11.009
M3 - Review article
AN - SCOPUS:85058374231
VL - 41
SP - 27
EP - 39
JO - Current Opinion in Colloid and Interface Science
JF - Current Opinion in Colloid and Interface Science
SN - 1359-0294
ER -