Dynamic viscosity was measured by
using a HAAKE Mars III rotational rheometer (Thermo Scientific) equipped
with a 35 mm titanium cone (cone angle 1°). A volume of 200 μL
of mAb sample was pipetted on a static surface and equilibrated for
5 min. The generated shear forces were analyzed via torque measurements.
The relation between dynamic viscosity (η), torque (M), angular velocity (ω), cone angle (α), and
cone radius (R) is according to Hartl et al.57 (link) and Mezger.58 The viscosity
was measured in controlled shear rate (CSR) mode with a rotation ramp
of τ = 100–1000 s–1 in 10 logarithmic
steps. The dynamic viscosity was measured at a constant temperature
of 297 K and a continuous shear rate of τ = 1000 s–1 for 100 s, with measurements averaged over 1 s intervals. Afterward,
the shear stress was recorded on a temperature ramp from 250 to 288
K in single measurements at a shear rate of 1000 s–1. The data were analyzed using the Haake RheoWin Data Manager software
(Thermo Fisher Scientific). The viscosity data at 297 K was used to
fit the Ross–Minton equation59 (link) where η0 is the viscosity
of the buffer solution, [η] is the intrinsic viscosity of the
solute, ρ is the mass concentration, k is a
crowding factor, and v is a shape parameter of the
solute molecule (v = 2.5 for a perfect sphere, v > 2.5 for nonspherical particles).
using a HAAKE Mars III rotational rheometer (Thermo Scientific) equipped
with a 35 mm titanium cone (cone angle 1°). A volume of 200 μL
of mAb sample was pipetted on a static surface and equilibrated for
5 min. The generated shear forces were analyzed via torque measurements.
The relation between dynamic viscosity (η), torque (M), angular velocity (ω), cone angle (α), and
cone radius (R) is according to Hartl et al.57 (link) and Mezger.58 The viscosity
was measured in controlled shear rate (CSR) mode with a rotation ramp
of τ = 100–1000 s–1 in 10 logarithmic
steps. The dynamic viscosity was measured at a constant temperature
of 297 K and a continuous shear rate of τ = 1000 s–1 for 100 s, with measurements averaged over 1 s intervals. Afterward,
the shear stress was recorded on a temperature ramp from 250 to 288
K in single measurements at a shear rate of 1000 s–1. The data were analyzed using the Haake RheoWin Data Manager software
(Thermo Fisher Scientific). The viscosity data at 297 K was used to
fit the Ross–Minton equation59 (link) where η0 is the viscosity
of the buffer solution, [η] is the intrinsic viscosity of the
solute, ρ is the mass concentration, k is a
crowding factor, and v is a shape parameter of the
solute molecule (v = 2.5 for a perfect sphere, v > 2.5 for nonspherical particles).