Construction Of Hybrid Microcapsules And Study On Its Membrane Permeability Regulation

The design and construction of hollow microcompartment is attracting considerable interest in a wide range of research communities in recent years.To fulfill the roles of microcapsules in kind of fields,a permeable membrane which is capable of controlling passage of guest molecules into and out of the interior core domain is a key concern and a prerequisite attribute in the design of models.Therefore,we proposed a universal and efficient method to regulate the membrane permeability of microcapsules.Such microcapsules with regulable membrane permeability,allow themselves showing more promising applications in different fields including biomedicine,catalysis,nanoreactors and artificial cells.Firstly,three kinds of biological molecules,dextran(with molecular weight of 70 kDa)and lysozyme(with molecular weight of 14 kDa)and bovine serum albumin(with molecular weight of 66 kDa),as raw materials,were endowed with enough amino functional group through a series of chemical modification.Then three kinds of corresponding amphiphilic conjugates were obtained though the action of amino and mercapto-thiazoline active ester of poly(N-isopropylacrylamide).After wards,three kinds of homogeneous microcapsules,two kinds of hybrid bi-microcapsules and a kind of hybrid tri-microcapsules were constructed though Pickering emulsion by self-assembly on the surface of water and oil.All kinds of microcapsules showed a hollow membrane construction,smooth,sphere and stable with size fro m 20?m to 60?m.With the addition of lysozyme-poly(N-isopropylacrylamide)and bovine serum albumin-poly(N-isopropylacrylamide),the Young's Modulus of dextran-poly(N-isopropylacrylamide)microcapsules decreased gradually,which proved the additional construction of the membrane.Aimed as the hybrid tri-microcapsules,the lysozymes could be removed out by tris(2-carboxyethyl)phosphine due to the cleavage of the disulfide bonds,and BSA could be removed out there after by adding proteases,which left corresponding pores on its membrane.Consequently,with the spread of FITC-dextran with molecular weight from 2kDa to 2000 kDa into the microcapsules,the molecular weight cutoff of the constructed hybrid tri-microcapsules could be turned up continuously from original 10 kDa to 22 kDa and furthermore to 71 kDa,then,in the presence of lyticase,the hydrolysis of the skeleton building blocks dextran-polymer will result in a complete disassembly of the microcapsules,which set the membrane permeability free.The programmed release of bio-molecules was achieved with the encapsulation of lysozyme(with molecular weight of 14 kDa),dextran(with molecular weight of 70 kDa)and DNA(with molecular weight of 90kDa).