la6b01885_si_001.pdf (136.21 kB)
Relative Contribution of Lateral Packing Density to Albumin Adsorption on Monolayers
journal contribution
posted on 2016-07-27, 00:00 authored by Leila Safazadeh, Victor
E. F. Zehuri, Samuel P. Pautler, J. Todd Hastings, Brad J. BerronThe
effect of functional group density on protein adsorption is
systematically studied to support ongoing efforts in molecular imprinting
of surfaces and bulk materials. In these applications, functional
commodity chemicals are molded to complement the shape and chemistry
of the target molecule. Here, we study the relationship between bovine
serum albumin adsorption and ligand density for carboxylate, alcohol,
and alkyl terminal groups. Control surfaces consisting of densely
packed self-assembled monolayers (SAMs) are contrasted with low-density
SAMs formed through thiol–yne chemistry. Direct comparison
consistently yielded greater protein adsorption on low-density SAMs
than conventional pure component SAMs of the same functional group.
Critically, the carboxylate and alcohol low-density SAMS are more
hydrophobic than their analogous dense SAMs. Mixed functional group,
dense SAMs were formed with alkyl diluents to match the hydrophobicity
of the low-density SAMs. Once hydrophobicity is matched, the dense
carboxylate and alcohol SAMs have higher adsorption than the low-density
SAMs. We conclude (1) surface charge and hydrophobicity trends dominate
over surface density contributions; (2) when hydrophobicity is matched,
greater adsorption occurs on dense hydrophilic groups than on lower
density hydrophilic groups; (3) when hydrophobicity is matched, greater
adsorption occurs on lower density hydrophobic groups than on higher
density hydrophobic groups.