The interaction between BSA and DOTAP at the air-buffer interface

Abstract

In this article, the interaction between bovine serum albumin (BSA) and the cationic 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) at the air-buffer interface was investigated at different subphase’s pH values (pH = 3, 5 and 10). Surface pressure measurements (π − A) and penetration kinetics process (π − t) were carried out to reveal the interaction mechanism and the dynamical behavior. The data showed that π − A isotherms moved towards larger mean molecular area when the concentration of BSA ([BSA]) increased, the amount of BSA adsorbed onto DOTAP monolayer reached a threshold value at a [BSA] of 5 × 10−8 M, and BSA desorbed from the lipid monolayer as time goes by. The results revealed that the association of BSA with DOTAP at the air-buffer interface was affected by the subphase’s pH value. When pH = 10, the interaction mechanism between them was a combination of hydrophobic interaction and electrostatic attraction, so BSA molecules could be well separated and purified from complex mixtures. AFM images demonstrated that pH value and [BSA] could affect the morphology feature of DOTAP monolayer and the adsorption and desorption processes of BSA. So the study provides an important experimental basis and theoretical support for learning the interaction mechanism among biomolecules in separation and purification of biomolecules and biosensor.

Interaction of a Phospholipid and a Coagulating Protein: Potential Candidate for Bioelectronic Applications

“…The analysis of compressibility values also indicates that lipid molecules attain maximum ordered and compact organization within the Langmuir films in the presence of PS for a waiting time of 120 min and when the PS amount present in the subphase is 1.75 mL. We have also drawn the compression modulus vs surface pressure ( C s –1 –π) curves from the isotherm characteristics using the formula, 72 , 73 …”

Surface Activities of a Lipid Analogue Room-Temperature Ionic Liquid and Its Effects on Phospholipid Membrane

“…The qualitative nature of the isotherm of this LA molecule is quite similar to the one reported in the case of the cationic 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP). 79,80 The chain configuration and the type of head group charge of DOTAP resemble those of the LA molecule. However, the chemical structures of the head groups are different.…”

Reversible pH Responsive Bovine Serum Albumin Hydrogel Sponge Nanolayer

“…However, a weak positive charge from the globular BSA protein can provide a sufficient drift for adsorption at an interface (Su et al, 1998a;Jachimska et al, 2016). Multiple articles have previously reported the adsorption of BSA and similar proteins near the isoelectric point to be driven by hydrophobic interactions which outweigh the electrostatic interactions (Uyen et al, 1990;Tilton et al, 1991;Figueira and Jones, 2008;Norde, 2008;Jeyachandran et al, 2009;Rabe et al, 2011;Huang et al, 2017;Xu et al, 2018;Attwood et al, 2019). The contact angle measurements (Figure 5) show the bare gold interface is less hydrophobic, and albumin binds with gold via hydrophobic interactions (Norde and Giacomelli, 2000;Figueira and Jones, 2008).…”