Jeannot Lucas, Bell Michael, Ashwell Ryan, Volodkin Dmitry, Vikulina Anna S
Robert Schuman University Institute of Technology (IUT Robert Schuman), University of Strasbourg, 72 Route Du Rhin, 67411 Illkirch CEDEX, France.
School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, UK.
Micromachines (Basel). 2018 Oct 25;9(11):547. doi: 10.3390/mi9110547.
Multilayer capsules templated on decomposable vaterite CaCO₃ crystals are widely used as vehicles for drug delivery. The capsule represents typically not a hollow but matrix-like structure due to polymer diffusion into the porous crystals during multilayer deposition. The capsule formation mechanism is not well-studied but its understanding is crucial to tune capsule structure for a proper drug release performance. This study proposes new approach to noninvasively probe and adjust internal capsule structure. Polymer capsules made of poly(styrene-sulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDAD) have been stained with fluorescence dye rhodamine 6G. Physical-chemical aspects of intermolecular interactions required to validate the approach and adjust capsule structure are addressed. The capsules consist of a defined shell (typically 0.5⁻2 µm) and an internal matrix of PSS-PDAD complex (typically 10⁻40% of a total capsule volume). An increase of ionic strength and polymer deposition time leads to the thickening of the capsule shell and formation of a denser internal matrix, respectively. This is explained by effects of a polymer conformation and limitations in polymer diffusion through the crystal pores. We believe that the design of the capsules with desired internal structure will allow achieving effective encapsulation and controlled/programmed release of bioactives for advanced drug delivery applications.
以可分解的球霰石型碳酸钙晶体为模板制备的多层胶囊被广泛用作药物递送载体。由于在多层沉积过程中聚合物扩散到多孔晶体中，该胶囊通常不是中空结构，而是类似基质的结构。胶囊的形成机制尚未得到充分研究，但对其的理解对于调整胶囊结构以实现适当的药物释放性能至关重要。本研究提出了一种非侵入性探测和调整胶囊内部结构的新方法。由聚（苯乙烯磺酸盐）（PSS）和聚（二烯丙基二甲基氯化铵）（PDAD）制成的聚合物胶囊已用荧光染料罗丹明6G染色。文中讨论了验证该方法和调整胶囊结构所需的分子间相互作用的物理化学方面。这些胶囊由确定的外壳（通常为0.5⁻2微米）和PSS-PDAD复合物的内部基质（通常占胶囊总体积的10⁻40%）组成。离子强度的增加和聚合物沉积时间的延长分别导致胶囊外壳增厚和更致密的内部基质形成。这可以通过聚合物构象的影响以及聚合物通过晶体孔隙扩散的限制来解释。我们相信，设计具有所需内部结构的胶囊将能够实现生物活性物质的有效包封和控释/程控释放，以用于先进的药物递送应用。
