FORMULATIONS FOR INTRACELLULAR DELIVERY dsRNA

1 . A composition for delivery of a RNA molecule to a cell, comprising: a double stranded RNA (dsRNA) molecule of about 15 to about 40 base pairs; and a cationic polymer peptide comprising at least two cysteine residues and at least one tryptophan residue with one or more repeats consisting of between about two to about 20 positively charged residues.

2 . The composition of claim 1 , wherein the peptide comprises two or more cysteine residues and one or more tryptophan residues with one or more repeats consisting of positively charged residues.

3 . The composition of claim 1 , wherein the peptide comprises two or more cysteine residues, one or more tryptophan residues, two or more histidine residues with one or more repeats consisting of positively charged residues.

4 . The composition of claim 1 , wherein the cationic polymer peptide has an amino acid sequence comprising Cys-Trp-(Lys) X -Cys (SEQ ID NO:29); Cys-Trp-(Lys) X -Cys-(Lys) X -Cys (SEQ ID NO:30); Cys-Trp-(Lys) X -His-(Lys) X -Cys (SEQ ID NO:31); Cys-Trp-His-(Lys) X -His-(Lys) X -Cys (SEQ ID NO:32) or Cys-Trp-His-(Lys) X -His-(Lys) X -His-Cys (SEQ ID NO:33), wherein X is greater than one and the total number of non-lysine residues is less than 18.

5 . The composition of claim 1 , wherein the cationic polymer peptide has an amino acid sequence comprising Cys-Trp-(Lys) 4 -Cys (SEQ ID NO:2) or Cys-Trp-(Lys) 6 -Cys (SEQ ID NO:3).

6 . The composition of claim 1 , wherein the peptide is pegylated.

7 . The composition of claim 1 , wherein the peptide is acetylated.

8 . The composition of claim 1 , wherein the composition is reacted with a dialdehyde to cross-link a multiplicity of peptides.

9 . The composition of claim 1 , wherein the peptides cross-link after binding to dsRNA by forming interpeptide disulfide bonds.

10 . The composition of claim 1 , wherein the peptide is derivatizing with a single N-glycan.

11 . A method of stabilizing a double stranded ribonucleic acid (dsRNA)-peptide condensate, comprising:

a. preparing a dsRNA-peptide condensate by mixing a dsRNA with a peptide in water, and

b. cross-linking at least a portion of the peptides within the condensate.

12 . The method of claim 11 , further comprising the steps of:

a. selecting a peptide comprising two or more lysine residues, and

b. cross-linking the peptides after binding to dsRNA by reacting with a dialdehyde.

13 . The method of claim 11 , further comprising the steps of:

a. selecting a peptide comprising two or more cysteine residues, and

b. cross-linking the peptides after binding to dsRNA by forming interpeptide disulfide bonds.

14 . A method for delivering a double stranded (ds)RNA molecule to a cell, comprising:

a. preparing a condensate comprising a dsRNA molecule of about 15 to about 40 base pairs;

b. preparing a dsRNA-peptide condensate by mixing a dsRNA with a peptide in water,

c. cross-linking at least a portion of the peptides within the condensate, and

d. contacting a cell with said condensate.

15 . The method of claim 14 , further comprising the steps of:

a. selecting a peptide comprising two or more lysine residues, and

b. cross-linking the peptides after binding to dsRNA by reacting with a dialdehyde.

16 . The method of claim 14 , further comprising the steps of:

a. selecting a peptide comprising two or more cysteine residues, and

b. cross-linking the peptides after binding to dsRNA by forming interpeptide disulfide bonds.

17 . A method for inhibiting expression of a gene in a cell comprising

a. preparing a condensate comprising a dsRNA molecule of about 15 to about 40 base pairs;

b. preparing a dsRNA-peptide condensate by mixing a dsRNA with a peptide in water,

c. cross-linking at least a portion of the peptides within the condensate, and

d. treating a cell with said condensate.