3.4 Application performance of MTCFs@SIP@CBMA
3.4.1 Adsorption kinetics
Under the premise that the initial concentration of BSA was 0.1 mg/mL,
the relationship between the adsorption capacity of MTCFs@SIP@CBMA and
MTCFs@NIP@CBMA on BSA over time was measured. As shown in Figure 6, the
adsorption process was obviously divided into four stages. At 0-30 min,
the adsorption capacity of MTCFs@SIP@CBMA on BSA gradually increased
with time. The reason was
described as that BSA first bound to the imprinted sites on the surface
of the fibers relying on electrostatic attraction, hydrogen bonding and
hydrophobic interaction. As time gone on, the binding amount increased.
At 30-60 min, the adsorption capacity remained unchanged, indicating
that the imprinted sites on MTCFs@SIP@CBMA surface reached saturation.
The saturated adsorption capacity for BSA was 395.26 mg/g. However, the
osmotic pressure difference between the inside and outside of the tube
would drive BSA to migrate into the cavity through the pores on the tube
wall. The balance of adsorption capacity suggested that the adsorbed BSA
still occupied the imprinting sites. At 30-100 min, the adsorption
capacity increased again with time, and the adsorption capacity was
significantly higher than the equilibrium adsorption capacity. This
illustrated that the BSA on the
surface of MTCFs@SIP@CBMA disengaged from the imprinting sites and
diffused into the cavity. At this time, the remaining BSA in the
solution again adsorbed to the imprinting sites on the surface. After
100 min, the BSA migrating into the cavity migrated out of the fiber
port and migrated outward at a rate greater than the adsorption rate, so
the adsorption amount decreased with time. The above adsorption results
well confirmed the self-driven adsorption performance of MTCFs@SIP@CBMA.
For MTCFs@NIP@CBMA, owing to the lack of imprinting sites matching with
BSA on its surface and the grafting of anti-protein adsorption chain
segments, the adsorption capacity was significantly lower than
MTCFs@SIP@CBMA (only 57.42 mg/g). Simultaneously, because MTCFs@NIP@CBMA
had no imprinted cavity connected to the carrier fibers and the coated
PDA and CBMA polymers were compact, the adsorption process of
MTCFs@NIP@CBMA did not exhibit self-driven adsorption performance.