The invention provides methods for protecting molecules from degradation in a bodily fluid like serum. In a first aspect, the method is for protecting a DNA dendrimer from degradation, and comprises the step of attaching the DNA dendrimer to a protein, digoxigenin, cholesterol, a primary amine, a hydrocarbon spacer of length of 3 to 120 carbons, a PEG molecule, biotin, a biotin derivative, fluorescein or a fluorescein derivative, or any combination thereof； thereby protecting the DNA dendrimer against nuclease degradation. In a second aspect, the method is for protecting a siRNA from degradation, comprising attaching the siRNA to a protected DNA dendrimer obtained in the first aspect； thereby protecting the siRNA against degradation.
