Morphology analysis using AFM
To analyze the morphology of the samples, AFM imaging was performed as
shown in Figure 5. The native BSA molecules were in globular shape with
an average size of 30-40 nm (Figure 5(a)). This size may be
overestimated due to the finite radius (~10 nm) of AFM
tip. For the samples sheared at constant 300 s-1 for
15 min, particles sizes were in the range of 50 to 70 nm (Figure 5(b))
i.e. slightly larger than native BSA. However, at higher temperatures 60
and 65°C, particle sizes were much increased due to the aggregation as
observed through enhanced Th-T fluorescence and loss of helicity. The
aggregate dimension ranges were 70-100 nm and 100-200 nm for the samples
sheared at 60°C and 65°C, respectively (Figures 5(c) and (d)). Here
mixtures of globular as well as elongated clumps were observed. These
sizes and shapes of aggregates agreed with the reported data
(Dubey et al. 2017). The size of
aggregates obtained after shearing at 65°C were found to be comparable
with thermal treated BSA at 75 °C (Figure 5(e)).