Microfluidic Fabrication of Colloidal Nanomaterials-Encapsulated Microcapsules for Biomolecular Sensing

Abstract

Implantable sensors that detect biomarkers in vivo are critical for early disease diagnostics. Although many colloidal nanomaterials have been developed into optical sensors to detect biomolecules in vitro, their application in vivo as implantable sensors is hindered by potential migration or clearance from the implantation site. One potential solution is incorporating colloidal nanosensors in hydrogel scaffold prior to implantation. However, direct contact between the nanosensors and hydrogel matrix has the potential to disrupt sensor performance. Here, we develop a hollow-microcapsule-based sensing platform that protects colloidal nanosensors from direct contact with hydrogel matrix. Using microfluidics, colloidal nanosensors were encapsulated in polyethylene glycol microcapsules with liquid cores. The microcapsules selectively trap the nanosensors within the core while allowing free diffusion of smaller molecules such as glucose and heparin. Glucose-responsive quantum dots or gold nanorods or heparin-responsive gold nanorods were each encapsulated. Microcapsules loaded with these sensors showed responsive optical signals in the presence of target biomolecules (glucose or heparin). Furthermore, these microcapsules can be immobilized into biocompatible hydrogel as implantable devices for biomolecular sensing. This technique offers new opportunities to extend the utility of colloidal nanosensors from solution-based detection to implantable device-based detection.

Generation of Ultra-Thin-Shell Microcapsules Using Osmolarity-Controlled Swelling Method

“…This kind of core-shell configuration not only can protect the core materials from external disturbance or even contamination, but can also perform the on-demand delivery and release of the aqueous core under various external stimuli [1,2]. Thus, microcapsules can serve as model systems in various applications, such as drug delivery and controlled release [3][4][5][6][7], photonic capsule sensors [8][9][10], artificial microbial environments [11,12], foods [13,14], and biomolecular sensing [15,16].…”

Tailoring the appearance: what will synthetic cells look like?

“…Additionally, one can also consider microcapsules, which are water-filled vesicles with a solid shell made up of polyelectrolytes, as potential synthetic cell containers. Microcapsules can be efficiently generated using microfluidics, and the mechanical and physiochemical properties, such as elasticity and permeability, can be readily controlled [51][52][53].…”

Synthesis of Biomaterials Utilizing Microfluidic Technology

“…Microcapsules are another important type of microspheres that normally have a core–shell structure. They have potential application in many fields including food additives [ 109 ], agriculture [ 110 , 111 ], microsensors [ 112 , 113 ], cell encapsulation [ 102 , 103 , 114 ], multiplex assays [ 115 ], and the controlled release of drugs in delivery systems [ 12 , 116 , 117 , 118 ]. Generally, the shape and size distributions of microcapsules have a considerable influence on their application properties.…”