Otherwise, the authors declare no competing financial interests

Otherwise, the authors declare no competing financial interests.. P1-(MORF2)x The P1-TT described above was reacted with MORF2-NH2 to produce multivalent P1-(MORF2)x (25 bp) or different sequences (20 or 28 bp). P1-TT (1 mg; = 86 kDa; containing 770 nmol TT groups) was mixed with MORF2-NH2-25 bp (1.1 mg, 130 nmol; 2.1 mg, 250 nmol; 5.1 mg, 600 nmol), MORF2-NH2-20 bp (4.1 mg, 600 nmol) or MORF2-NH2-28 bp (5.8 mg, 600 nmol) in 200 L PBS (pH 7.4). The solution mixture in an ampoule was stirred at RT for 24 h; then 1 L 1-amino-2-propanol was added and stirred for another 15 min to aminolyze unreacted EMR2 TT groups on the polymer chains, if any. After reaction, unreacted MORF2-NH2 was removed by ultrafiltration (30,000 Da cut-off) four times with DI H2O. P1-(MORF2)x was characterized by UV absorbance at 265 nm. To quantify the content of MORF2 and determine the valence (number of MORF2 per polymer chain), the P1-(MORF2)x conjugates were freeze-dried and dissolved in 0.1 N HCl prior to UVCVis analysis. The molar absorptivity of MORF2-20 bp, MORF2-25 bp and MORF2-28 bp were 201,090 M?1 cm?1, 252,120 M?1 cm?1 and 280,910 M?1 cm?1, respectively (at 265 nm, in 0.1 N HCl). The valences of the P1-(MORF2)x conjugates were calculated based on the resulting MORF2 contents and the of the polymer backbones (as previously determined by SEC). Synthesis of multivalent P2-PEG2-MORF2, P2-PEG8-MORF2 and P3-PEG2-MORF2 conjugates These conjugates were prepared by the reaction of HPMA copolymer containing maleimido groups at side chain termini with 3-thiol modified MORF2 GSK9311 (Scheme 1C). Briefly: Synthesis of P2-PEG2-mal, P2-PEG8-mal and P3-PEG2-mal In RAFT copolymerization, CPDB was used as the CTA and V-501 as the initiator. The reaction was carried out in H2O. A typical procedure was as follows: HPMA (129 mg, 0.9 mmol) and APMA (17.8 mg, 0.1 mmol) were added into an ampoule attached to a Schlenk line. After three vacuum nitrogen cycles to remove oxygen, 600 L degassed H2O was added to dissolve monomers, followed by addition of 0.33 mg CPDB (or 0.16 mg, in 33 L MeOH) and 0.17 mg V501 solution (or 0.08 mg, in 17 L MeOH) via syringe. The mixture was bubbled with nitrogen for 30 min before sealing the ampoule; the copolymerization was performed at 70 C for 24 h (or 40 h). The copolymers were purified by dialysis in DI H2O and the products isolated by freeze-drying. Yield of P2-NH2 was 115 mg, 78% and of P3-NH2 118 mg, 79%. and PDI of P2-NH2 and P3-NH2 were 112 kDa and 1.17 or 291 kDa and 1.17, respectively as determined GSK9311 by SEC, using ?KTA FPLC equipped with Superose 6 HR10/30 column with PBS buffer as the mobile phase. After end-modification with 40-times excess of V-65, the amino content of the copolymers was determined by ninhydrin assay [49]. P2-NH2: [NH2]: 75 per copolymer chain, = 112 kDa; P3-NH2: [NH2]: 151 per copolymer chain, = 291 kDa. P2-NH2 was mixed with 2 eq. SM(PEG)2 GSK9311 (or SM(PEG)8) and stirred at RT for 6 h to prepare P2-PEG2-mal (or P2-PEG8-mal). The excess SM(PEG)2 (or SM(PEG)8) was removed by ultrafiltration (30 kDa cutoff) four times with DI H2O/MeOH (9/1). Maleimide group content GSK9311 was determined by modified Ellmans assay [50]: ([mal]: 54.