Useful Oriented Immobilization of Antibodies on Chimeric Magnetic Particles: Direct Correlation of Biomacromolecule Orientation with Biological Activity by AFM Studies

Abstract

The preparation and performance of a suitable chimeric biosensor basedon antibodies (Abs) immobilized on lipase-coated magnetic particles by means of astanding orienting strategy are presented. This novel system is based on hydrophobicmagnetic particles coated with modified lipase molecules able to orient and furtherimmobilize different Abs in a covalent way without any previous site-selective chemicalmodification of biomacromolecules. Different key parameters attending the process werestudied and optimized. The optimal preparation was performed using a controlled loading(1 nmol Ab g−1chimeric support) at pH 9 and a short reaction time to recover abiological activity of about 80%. AFM microscopy was used to study and confirm the Abs-oriented immobilization on lipase-coated magnetic particles and thefinal achievement of ahighly active and recyclable chimeric immune sensor. This direct technique wasdemonstrated to be a powerful alternative to the indirect immunoactivity assay methodsfor the study of biomacromolecule-oriented immobilizations.