One‐Step Generation of Core–Gap–Shell Microcapsules for Stimuli‐Responsive Biomolecular Sensing

Hyejeong Kim,Katharina Landfester,Héloïse Thérien‐Aubin,Fanlong Meng,Eberhard Bodenschatz,Seong‐Min Jo,Ramin Golestanian,Yinzhou Guo

doi:10.1002/adfm.202006019

Abstract

AbstractThe versatile design of stimuli‐responsive microparticles embedding valuable biomolecules has great potential in a variety of engineering fields, such as sensors, actuators, drug delivery, and catalysis. Here, results are reported on thermoresponsive core–gap–shell (TCGS) microcapsules made of poly(N‐isopropylacrylamide) (PNIPAm), which encapsulate hydrophilic payloads in a simple and stable manner. These are realized by a one‐step microfluidic approach using the phase separation of a supersaturated aqueous solution of NIPAm. Various designs of the microcapsules are achieved by individual control of the swelling or by incorporating pH‐responsive comonomers of the inner core and outer shell. The gap, i.e., the space between the inner core and outer shell, can be loaded with cargo‐like nanoparticles. The outer shell can serve as a stimuli‐responsive gateway for the transport of smaller molecules from the external solution. It is shown that the TCGS microcapsules are suitable as temperature controllable glucose sensors and hold promise in the design of controllable enzymatic reactions. The proposed platform provides an avenue for developing a new‐generation of microparticles for diverse and efficient engineering applications.

Highlights

By leveraging the thermodynamic properties of supersaturated NIPAm solution, thermoresponsive core–gap–shell (TCGS) microcapsules can be produced from Wn-poor/Wn-rich/O double emulsions generated from a polydimethylsiloxane (PDMS) microfluidic device (Figure 1)
The design variability of the microcapsules was demonstrated by individually controlling the water absorption ability of the inner core and outer shell
A free-radical polymerization with pH-responsive itaconic acid at the inner core or the outer shell of the capsule resulted in a poly(NIPAm-co-itaconic acid)(P(NIPAm-co-IA)), which has dualresponsiveness

Summary

Introduction

Results are reported on thermoresponsive core–gap–shell (TCGS) microcapsules made of poly(Nisopropylacrylamide) (PNIPAm), which encapsulate hydrophilic payloads in Droplet microfluidics can produce microdroplets with precisely tunable configurations at high throughput.[1] Recent advances in microfluidics have established multiple-emulsion technologies, which allow a simple and stable manner. These are realized by a one-step microfluidic the fabrication of microcapsules with a approach using the phase separation of a supersaturated aqueous solution of NIPAm. Various designs of the microcapsules are achieved by individual control of the swelling or by incorporating pH-responsive comonomers of the inner core and outer shell.

Methods

Results

Conclusion