Microfluidic one-step fabrication of radiopaque alginate microgels with in situ synthesized barium sulfate nanoparticles

Abstract

In this work, we report a new strategy to fabricate monodispersed radiopaque alginate (Ba-alginate) microgels by a one-step microfluidic method. Alginate droplets containing sulfate ions are first formed by a flow focusing microfluidic setup. These alginate droplets are subsequently solidified by barium ions in a collection bath. During the solidification process, excessive barium ions in the collection bath also react with sulfate ions in the alginate droplet, resulting in barium sulfate (BaSO(4)) nanoparticles in situ synthesized (acting as radiopaque imaging agents) within the Ba-alginate microgels. Scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX) illustrate that 800 nm BaSO(4) nanoparticles are uniformly distributed inside the 30 μm Ba-alginate microgels, with 62 wt% of elemental barium (Ba). In addition, X-ray diffraction (XRD) measurements indicate that the BaSO(4) nanoparticles consist of 10 nm in situ synthesized BaSO(4) crystallites. The alginate microgels act as a soft and porous template to prevent the precipitation and aggregation of BaSO(4) nanoparticles. The Ba-alginate microgels are also visible under X-ray radiation. The facile route to fabricate alginate microgels as radiopaque embolic materials is of particular importance for endovascular embolization and localized diagnostic imaging applications. Similar approaches can also be adopted for synthesizing other inorganic nanoparticles in microgels.

Polymer Micro‐ and Nanocapsules as Biological Carriers with Multifunctional Properties

“…Using microfluidic approach, different cargos can be directly emulsified and loaded into microdroplets without any material lost. Biocompatible alginate microgels (diameter 30 μm) containing barium sulfate nanoparticles (diameter 800 nm) as an inherent imaging agent for embolization application were produced by a droplet microfluidics‐based method combined with an external solidification setup . Bacillus thuringiensis spores were encapsulated and cultivated inside the bioactive monodisperse PNIPAM‐based microcapsules, which were produced in one‐step process by using a combination of a microfluidic device and the chemical polymerization method .…”

A microdevice for producing monodispersed droplets under a jetting flow

“…FF devices come up with an orice to control the droplet behaviors. [28][29][30] Phase change process was introduced in FF devices to prepare tiny and complex droplets. They found a simple scaling law for the prediction of droplet sizes.…”

Perspective: Flicking with flow: Can microfluidics revolutionize the cancer research?

“…[96][97][98] Preparation of microspheres with uniform size is a problem in this field, and microfluidic devices have already been proposed to solve that. 99 Also to this end, from the perspectives of fluid mechanics, it is interesting to study the dynamics of microspheres in a confined and complex fluid flow. A group of researchers has recently designed a microfluidic system with essential topological attributes of the circulatory network of the body and studied the spatial statistics of flow blocking by the embolic microspheres inside the system.…”