Antibody-nanoparticle conjugates and methods for making and using such conjugates

A method for producing an antibody-nanoparticle conjugate, comprising:

• Providing a reduced intact antibody comprising 2 heavy chains and 2 light chains and having at least one thiol group, wherein the 2 heavy chains are covalently coupled to each other through at least one interchain disulfide bond;
• the reduced intact antibody is produced by reducing an intact antibody comprising two heavy chains and two light chains with dithiothreitol (DTT) under condition such that at least one thiol group is formed by reduction of at least one of a native interchain disulfide or a native intrachain disulfide of the intact antibody wherein the 2 heavy chains of the reduced intact antibody are covalently coupled to each other through at least one interchain disulfide bond;
• and
• reacting the reduced intact antibody with an arylphosphine-nanoparticle composite and coupling the reduced intact antibody directly without an intervening linker to the arylphosphine-nanoparticle composite through the at least one formed thiol group through a metal-thiol bond, thereby producing the antibody-nanoparticle conjugate.