Guo Jianhua, Hou Lihua, Hou Junpeng, Yu Jiali, Hu Qingming
School of Mechatronics Engineering, Qiqihar University, Wenhua Street 42, Qiqihar 161006, Heilongjiang, China.
Micromachines (Basel). 2020 Apr 23;11(4):444. doi: 10.3390/mi11040444.
Microcapsules are attractive core-shell configurations for studies of controlled release, biomolecular sensing, artificial microbial environments, and spherical film buckling. However, the production of microcapsules with ultra-thin shells remains a challenge. Here we develop a simple and practical osmolarity-controlled swelling method for the mass production of monodisperse microcapsules with ultra-thin shells via water-in-oil-in-water (W/O/W) double-emulsion drops templating. The size and shell thickness of the double-emulsion drops are precisely tuned by changing the osmotic pressure between the inner cores and the suspending medium, indicating the practicability and effectiveness of this swelling method in tuning the shell thickness of double-emulsion drops and the resultant microcapsules. This method enables the production of microcapsules even with an ultra-thin shell less than hundreds of nanometers, which overcomes the difficulty in producing ultra-thin-shell microcapsules using the classic microfluidic emulsion technologies. In addition, the ultra-thin-shell microcapsules can maintain their intact spherical shape for up to 1 year without rupturing in our long-term observation. We believe that the osmolarity-controlled swelling method will be useful in generating ultra-thin-shell polydimethylsiloxane (PDMS) microcapsules for long-term encapsulation, and for thin film folding, buckling and rupturing investigation.
微胶囊是用于控释、生物分子传感、人工微生物环境和球形薄膜屈曲研究的有吸引力的核壳结构。然而，生产具有超薄壳的微胶囊仍然是一个挑战。在此，我们开发了一种简单实用的渗透压控制溶胀方法，通过水包油包水（W/O/W）双乳液滴模板法大规模生产具有超薄壳的单分散微胶囊。通过改变内核与悬浮介质之间的渗透压，可以精确调节双乳液滴的尺寸和壳厚度，这表明这种溶胀方法在调节双乳液滴及所得微胶囊的壳厚度方面具有实用性和有效性。该方法能够生产出壳厚度小于数百纳米的超薄壳微胶囊，克服了使用经典微流控乳液技术生产超薄壳微胶囊的困难。此外，在我们的长期观察中，超薄壳微胶囊能够保持其完整的球形长达1年而不破裂。我们相信，渗透压控制溶胀方法将有助于制备用于长期封装的超薄壳聚二甲基硅氧烷（PDMS）微胶囊，并用于薄膜折叠、屈曲和破裂研究。
