Figure 1 Synthesis schematic diagram of MTCFs@SIP@CBMA
Influence of CBMA polymer chain length on the imprinting factor of MTCFs@SIP@CBMA
The strength of the anti-protein effect depended on the length of the CBMA polymer segments. Meanwhile, the length of the CBMA polymer segments could be intuitively reflected by the thickness of the CBMA polymer layer. The length of the CBMA anti-protein adsorption chain was controlled by changing the amount of CBMA added during the amino-Michael addition process. As shown in Figure 2a, the thickness of the CBMA layer gradually increased as the dose of CBMA increased, indicating that the length of the CBMA polymer chain gradually increased. The effect of CBMA polymer chain length on the adsorption capacity and imprinting factor of MTCFs@SIP@CBMA is shown in Figure 2b. It can be seen that with the increase of CBMA polymer chain length, the adsorption capacity of MTCFs@SIP@CBMA on BSA gradually decreased, while the imprinting factor demonstrated a trend of first increasing and then decreasing. This was attributed to the weak anti-protein effect when the CBMA chain length was too short. So, the non-specific adsorption of the materials for non-template proteins cannot be effectively reduced. However, too long CBMA chains could easily lead to strong anti-protein adsorption effect and increase steric hindrance, which was not conducive to the binding of template proteins to imprinting sites. The experimental results suggested that when the mass ratio of BSA-MTCFs@SIP to CBMA was 1:10, the CBMA chain length was the most appropriate. MTCFs@SIP@CBMA possessed the highest imprinting factor for BSA. Therefore, MTCFs@SIP@CBMA prepared at this ratio was employed in the subsequent experiments. According to the results obtained, to significantly improve the recognition selectivity of imprinted materials, it was necessary to ensure that the imprinting sites were not severely affected by the CBMA anti-protein adsorption segments, while the effect of anti-protein adsorption chain segments reducing non-specific adsorption should be maximized by optimizing the chain length of CBMA polymers.