Laboratorio de Biofisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico.
Instituto de Química, Universidad Nacional Autónoma de México, P. O. Box 70-213, Mexico City, Mexico.
Ultrason Sonochem. 2021 Jun;74:105556. doi: 10.1016/j.ultsonch.2021.105556. Epub 2021 Apr 15.
The use of ultrasound to generate mini-emulsions (50 nm to 1 μm in diameter) and nanoemulsions (mean droplet diameter < 200 nm) is of great relevance in drug delivery, particle synthesis and cosmetic and food industries. Therefore, it is desirable to develop new strategies to obtain new formulations faster and with less reagent consumption. Here, we present a polydimethylsiloxane (PDMS)-based microfluidic device that generates oil-in-water or water-in-oil mini-emulsions in continuous flow employing ultrasound as the driving force. A Langevin piezoelectric attached to the same glass slide as the microdevice provides enough power to create mini-emulsions in a single cycle and without reagents pre-homogenization. By introducing independently four different fluids into the microfluidic platform, it is possible to gradually modify the composition of oil, water and two different surfactants, to determine the most favorable formulation for minimizing droplet diameter and polydispersity, employing less than 500 µL of reagents. It was found that cavitation bubbles are the most important mechanism underlying emulsions formation in the microchannels and that degassing of the aqueous phase before its introduction to the device can be an important factor for reduction of droplet polydispersity. This idea is demonstrated by synthetizing solid polymeric particles with a narrow size distribution starting from a mini-emulsion produced by the device.
超声法可用于制备平均粒径为 50nm 至 1μm 的亚微米乳液和平均粒径小于 200nm 的纳米乳液，在药物输送、颗粒合成以及化妆品和食品工业中具有重要的应用价值。因此，人们期望开发新的策略，以更快地获得新的制剂，同时减少试剂的消耗。本研究提出了一种基于聚二甲基硅氧烷（PDMS）的微流控装置，可在连续流中利用超声作为驱动力来制备水包油或油包水型亚微米乳液。与微器件附着在同一玻璃载片上的朗之万（Langevin）压电换能器可提供足够的功率，在单个周期内无需试剂预均化即可产生亚微米乳液。通过将四种不同的流体独立引入微流控平台，可以逐步改变油相、水相和两种不同表面活性剂的组成，以确定最有利于减小粒径和降低多分散性的配方，使用的试剂少于 500μL。研究发现，空化气泡是微通道中乳液形成的最重要机制，并且在将水相引入装置之前对其进行脱气可能是降低液滴多分散性的一个重要因素。通过使用该装置制备的亚微米乳液来合成具有较窄粒径分布的固态聚合物颗粒，证明了这一想法。
