Solubility Determination
To assess their relative solubility, the BsAbs were concentrated to 20 mg/ml in PBS buffer using 100K MWCO ultrafiltration concentrators. Samples were stored at 5°C for 10 days prior to visual inspection and turbidity assessment. Turbidity was determined by absorbance at 550nm calibrated to a standard curve of turbidity NTU calibration standards (Sigma). Following the 10-day at 5°C hold, samples were stored for an additional 7-days at 37°C and assessed visually and for turbidity by absorbance at 550nm.