Reagents and methods for blocking non-specific interactions with nucleic acids

A method of blocking non-specific interactions with a nucleic acid of interest in a sample, the method comprising contacting the sample with a multivalent blocker, said multivalent blocker comprising at least three negatively charged polymers linked to a non-protein scaffold, wherein the non-protein scaffold is a positively charged dendrimer, wherein the multivalent blocker binds to positively charged compounds or materials in the sample, thereby blocking non-specific interactions with the nucleic acid of interest, wherein the negatively charged polymers are linked to the non-protein scaffold covalently or noncovalently and, wherein the nucleic acid of interest is DNA or RNA.