Fig. 4. (A) Rabbit IgG activity recovered after 3 days storage at –20 °C relative to fresh antibody in a surface binding assay. ** represents p < 0.01, error bars are from a minimum of 6 repeats; (B) schematic showing ease of freezing methodology; (C) DLS curves of insulin before (solid) and after (dashed) 12 freeze/thaw cycles. Black = insulin only, Red = insulin + PVA, Green = +2 kDa PEG + PVA, Blue = + 4 kDa PEG + PVA. IN all cases PEG = 100 mg mL^–1 and PVA =1 mg mL^–1. (D) Average size of insulin aggregates after 6 or 12 FT cycles in indicated conditions.