Electrospinning Equipment for Research| Facile fabrication of surface imprintedpolymers based on nanofibrous aerogels forspecific capture of lysozyme form egg white

Dr. Lu Jianwei and Prof. Guo Li's Team at Jiangsu University: Design and Construction of 3D Nanofibrous Aerogel-Based Surface-Imprinted Polymers for Efficient Lysozyme Adsorption and Separation

Surface imprinting technology is a molecular recognition technique based on the antigen-antibody reaction mechanism. By constructing imprinting layers on functionalized material surfaces, it achieves sensitive recognition and specific separation/purification of template proteins through the complementarity of imprinted cavities, demonstrating unique advantages in protein adsorption and separation. However, current imprinted polymers are mostly constructed on low-dimensional surface materials such as zero-dimensional nanoparticles, one-dimensional fibers, or two-dimensional films. These materials generally suffer from inherent defects including low adsorption capacity, poor structural stability, and slow elution rates, posing challenges for efficient and large-scale protein adsorption/separation.

Recently, Dr. Lu Jianwei from Jiangsu University published new research titled "Facile fabrication of surface imprinted polymers based on nanofibrous aerogels for specific capture of lysozyme from egg white" in *Food Chemistry*. The researchers introduced molecularly imprinted layers onto three-dimensional nanofibrous aerogel surfaces to construct imprinted polymers for efficient lysozyme purification. Compared with traditional imprinting materials, the obtained imprinted polymers exhibit superior structural stability, high specificity, and large adsorption capacity. Master's student Qiao Yufei from Jiangsu University's School of Materials Science and Engineering is the first author, with Prof. Guo Li as corresponding author.

Figure 1: Preparation, mechanism, and potential applications of LIPCNAs

The study used melt extrusion phase separation to prepare poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibers, followed by freeze-drying and grafting modification to produce carboxylated nanofibrous aerogels. Through electrostatic interactions and dopamine self-polymerization, an imprinting layer encapsulating lysozyme template molecules was constructed on the aerogel surface. After template molecule elution, nanofibrous aerogel-based imprinted polymers (LIPCNAs, Figure 1) were obtained. Benefiting from the interconnected porous architecture of nanofibrous aerogels and the complementarity of imprinted polymer cavities, LIPCNAs achieve efficient and specific lysozyme adsorption. The material also demonstrates excellent practical performance, enabling direct extraction of target proteins from egg white to obtain lysozyme with stable secondary structure and bioactivity, showing broad potential applications in biomedicine and food health.

Figure 2: Schematic of lysozyme recognition mechanism by LIPCNAs and TEM images of single fibers

As shown in Figure 2a, the polydopamine (PDA) imprinting layer self-assembles on nanofiber surfaces through non-covalent forces (π-π stacking, hydrogen bonds, etc.). After chemically eluting templates from the imprinting layer, specific cavities matching lysozyme in shape, size, and properties are obtained, enabling efficient template recognition. TEM images show smooth surfaces of individual PVA-co-PE NFAs nanofibers (Figure 2b), which become rough after grafting modification (Figure 2c). After imprinting, translucent N-containing imprinting layers are observed on LIPCNAs fiber surfaces (Figures 2d,e), with controllable thickness (1.51 nm/h) providing abundant lysozyme-specific recognition sites.

Figure 3: Underwater compression performance of LIPCNAs

LIPCNAs exhibit excellent mechanical behavior adaptable to underwater environments, fully recovering their original shape under various compressive strains (Figures 3a-c). After 50 compression cycles, LIPCNAs maintain stable mechanical compression performance and shape integrity (Figures 3d-g). This outstanding underwater mechanical performance stems from: (1) glutaraldehyde crosslinking helping construct a robust 3D network framework that effectively disperses stress concentration; (2) the surface-coated rigid PDA imprinting layer further reinforcing the fiber skeleton, providing structural stability for long-term aqueous use (Figure 3h).

Figure 4: Adsorption performance of LIPCNAs

Although the imprinting factor of LIPCNAs is only 1.53 (18h polymerization time, Figures 4a,b) due to cation-π and π-π interactions between PDA and template lysozyme, LIPCNAs still show remarkable lysozyme-specific recognition, with selectivity coefficients (α) reaching 4.73 for bromelain and 3.00 for papain (Figure 4c). As interactions between LIPCNAs and lysozyme vary with pH, optimal adsorption occurs at pH=8.0 where interactions are strongest (Figures 4d,e). Lysozyme adsorption by LIPCNAs reaches equilibrium in about 7 hours, following pseudo-second-order kinetics (chemical adsorption) and Langmuir monolayer adsorption models (Figures 4f,g). Protein gel electrophoresis confirms LIPCNAs' precision in separating lysozyme from egg white (Figure 4h).

The surface-imprinted nanofibrous aerogel LIPCNAs developed in this study enable rapid, efficient, and precise lysozyme adsorption/separation, providing a new material design approach for lysozyme purification.

Paper link: https://doi.org/10.1016/j.foodchem.2025.144449