Methods for preparing libraries of unique tags and related screening methods

A method for preparing a population of uniquely tagged non-cellular physical entities, comprising:

• (a) contacting a population of non-cellular physical entities with a chemical agent;
• (b) applying energy to one or more targeted physical entities, the energy capable of inducing attachment of the chemical agent to a targeted physical entity;
• (c) separating unattached chemical agent from chemical agent attached to the one or more targeted physical entities, and
• (d) repeating steps (a), (b) and (c) using a distinct chemical agent to produce a population of uniquely tagged non-cellular physical entities.

A method for preparing a population of uniquely tagged probes, comprising:

• (a) contacting a population of uniquely tagged non-cellular physical entities with a target moiety;
• (b) applying energy to one or more targeted uniquely tagged physical entities, the energy capable of inducing attachment of the target moiety to a targeted physical entity;
• (c) separating unattached target moiety from target moiety attached to the one or more targeted uniquely tagged physical entities, and
• (d) repeating steps (a), (b) and (c) using a distinct target moiety to label another member of the population of physical entities, thereby generating a population of uniquely tagged probes.