Biomimetic Particles

Electrostatically driven bilayer coverage from bilayer fragments onto oppositely charged latex produces a highly homodisperse particulate for biomolecules adsorption. Polystyrene sulfate (PSS) particles were covered with single cationic dioctadecyldimethylammonium bromide (DODAB) bilayers. Biomolecules adsorbed were DNA, bovine serum albumin (BSA), cholera toxin (CT) and a mixture of purified 18 kDa/14 kDa Taenia crassiceps proteins (18/14‐ Tcra ). Firstly, the DODAB/PSS assembly was characterized at 1 mM NaCl and 5 × 10 9 PSS particles/mL over a range of DODAB concentrations (0.001 ‐1 mM) by means of dynamic light scattering for particle sizing and zeta‐potential analysis. 0.01 mM DODAB was enough to produce perfectly homodisperse and cationic bilayer‐covered particles. Secondly, under these experimental conditions, BSA, CT, and 18/14‐ Tcra adsorbed onto biomimetic bilayer‐covered particles yielding langmuirian isotherms with 1.23 × 10 17 , 0.82 × 10 17 , 3.37 × 10 17 molecules per m 2 at limiting adsorption and affinity constants ( K ) of 3.17 × 10 10 , 3.39 × 10 10 , and 1.75 × 10 10 M −1 , respectively. For DNA adsorption, isotherms did not attain an adsorption maximum up to 20 micrograms/mL DNA. PSS/DODAB/biomolecule assemblies were also characterized by means of dynamic light scattering and zeta‐potential analysis yielding highly monodisperse particles at and above maximal adsorption. In summary cationic bilayer‐covered particles are a novel, highly organized and, possibly, general support for biomolecules immobilization.