Professor Wu Hong, South China University of Technology: Highly hydrophobic composite nanofiber carriers regulate the colonic release rate of lactoferrin and realize the effective exertion of its anti-colon cancer activity
Lactoferrin is an important whey functional protein with a variety of biological activities. However, due to its sensitivity to the gastrointestinal environment, its biological activity can be easily destroyed during oral delivery, limiting its application in the field of functional foods. In order to improve the oral stability of lactoferrin and maintain its biological activity, the construction of an efficient colonic delivery system is an effective strategy. However, the commonly used polysaccharide-based wall materials have unsatisfactory colonic delivery due to their hydrophilic swelling properties. Improving the hydrophobicity of the carrier material can improve the colonic delivery efficiency of the active substance, but at the same time, it will also lead to a slow release rate, which will affect the exertion of biological activity.
Recently, Professor Wu Hong's team from South China University of Technology published the latest research results "regulation of the colon-targeted release rate of lactoferrin by constructing hydrophobic ethyl" in the journal "International Journal of Biological Macromolecules". cellulose pectin composite nanofibrous carrier and its effect on anti-colon cancer activity”。 Based on polymers such as ethyl cellulose and pectin, the researchers developed a highly hydrophobic composite nanofiber carrier (CNC) loaded with lactoferrin through emulsion coaxial electrospinning technology, and added an intermediate layer composed of pectin between the hydrophobic ethylcellulose shell and the nuclear layer where lactoferrin is located, and changed the content of pectin to regulate the microstructure of the carrier, thereby regulating the release rate of lactoferrin. The faster the rate of lactoferrin release in the complex vector, the higher its anti-colon cancer activity.
Firstly, by adjusting the viscosity and conductivity of the aqueous solution of pectin in the pectin ethylcellulose wo shell emulsion to improve its electrostatic spinnability, a spinnability relationship diagram was established (Fig. 1a), and nanofibers with complete morphology and uniform diameter were obtained with pectin dispersed phase % and 20% wo emulsion, respectively (Fig. 1b). Then, four composite nanofibers 5&95 CNC, 10&90 CNC, 15&85 CNC and 20&80 CNC were prepared by the above four WO emulsions with different dispersed phase mass ratios as the shell layer and the PVA aqueous solution containing lactoferrin as the core layer.
Fig.1 Optimization of the preparation conditions of composite nanofiber carriers.
TEM characterization results show that these composite supports have a nanofiber nucleus layer, an intermediate layer in which dispersed phase particles and ethylcellulose are co-continuously distributed, and a thinner outer layer (Fig. 1C), and the water contact angle (>130°) also demonstrates their high hydrophobicity. Lactoferrin was successfully encapsulated into composite nanofibers and interacted with the polymer carrier. The in vitro gastrointestinal digestion-colonic fermentation process showed that the release of lactoferrin in the upper gastrointestinal tract (simulated gastric and small intestinal fluids) was < 5% (Fig. 2C), and lactoferrin was efficiently delivered to the colon by composite nanofiber carriers, and the content of pectin in composite nanofibers significantly affected the colonic release behavior (release amount and release time) of lactoferrin. The time to complete lactoferrin release during colonic fermentation was 3 h and 5&95 CNC, 10&90 CNC, 15&85 CNC, and 20&80 CNC, respectively, and the morphological changes of composite nanofibers were closely related to their release behavior (Fig. 2D). Importantly, MTT analysis, fluorescence observation, and Western blot studies have shown that the rate of colonic release of lactoferrin significantly affects its anti-colon cancer activity, i.e., the faster the release rate, the higher the anti-colon cancer activity (Figure 3). In conclusion, these structurally adjustable composite nanofiber carriers have potential applications in the field of functional foods.
Fig.2 Structural characterization of composite nanofiber carriers and lactoferrin release behavior.
Fig.3 Anti-colon cancer activity of lactoferrin.
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Wu Hong is a professor and doctoral supervisor at the School of Food Science and Engineering, South China University of Technology. In recent years, he has been mainly engaged in research on food nutrition and health, lipid chemistry, microbial engineering, etc. He has undertaken more than 30 projects such as National Natural Science, New Teachers of the Ministry of Education, and Natural Science of Guangdong Province. He has published more than 150 SCI articles, obtained 20 national invention patents, published 2 textbooks, and won 1 second prize of Guangdong Natural Science Award. He is currently the deputy director of the Institute of Food Bioengineering, School of Food Science and Engineering, South China University of Technology, a member of the Technical Committee of the National Liquor Standardization Technical Committee, a director of the Guangdong Biophysical Society, a member of the American Chemical Society, a member of the Chinese Society of Microbiology, and a member of the editorial board of Foods Chemistry, Food Hydrocolloids, Carbohydrate Polymers, Reviewer of Food Science and other academic journals at home and abroad.