The role of surface functionalization of colloidal alumina particles on their controlled interactions with viruses

Materials that interact in a controlled manner with viruses attract increasing interest in biotechnology, medicine, and environmental technology. Here, we show that virus-material interactions can be guided by intrinsic material surface chemistries, introduced by tailored surface functionalizations. For this purpose, colloidal alumina particles are surface functionalized with amino, carboxyl, phosphate, chloropropyl, and sulfonate groups in different surface concentrations and characterized in terms of elemental composition, electrokinetic, hydrophobic properties, and morphology. The interaction of the functionalized particles with hepatitis A virus and phages MS2 and PhiX174 is assessed by virus titer reduction after incubation with particles, activity of viruses conjugated to particles, and imaged by electron microscopy. Type and surface density of particle functional groups control the virus titer reduction between 0 and 99.999% (5 log values). For instance, high sulfonate surface concentrations (4.7 groups/nm(2)) inhibit attractive virus-material interactions and lead to complete virus recovery. Low sulfonate surface concentrations (1.2 groups/nm(2)), native alumina, and chloropropyl-functionalized particles induce strong virus-particle adsorption. The virus conformation and capsid amino acid composition further influence the virus-material interaction. Fundamental interrelations between material properties, virus properties, and the complex virus-material interaction are discussed and a versatile pool of surface functionalization strategies controlling virus-material interactions is presented.