Utilizing microfluidics to synthesize polyethylene glycol microbeads for Förster resonance energy transfer based glucose sensing

Abstract

Here, we utilize microfluidic droplet technology to generate photopolymerizeable polyethylene glycol (PEG) hydrogel microbeads incorporating a fluorescencebased glucose bioassay. A microfluidic T-junction and multiphase flow of fluorescein isothiocyanate dextran, tetramethyl rhodamine isothiocyanate concanavalin A, and PEG in water were used to generate microdroplets in a continuous stream of hexadecane. The microdroplets were photopolymerized mid-stream with ultraviolet light exposure to form PEG microbeads and were collected at the outlet for further analysis. Devices were prototyped in PDMS and generated highly monodisperse 72 6 2 lm sized microbeads (measured after transfer into aqueous phase) at a continuous flow rate between 0.04 ml/h-0.06 ml/h. Scanning electron microscopy analysis was conducted to analyze and confirm microbead integrity and surface morphology. Glucose sensing was carried out using a Förster resonance energy transfer (FRET) based assay. A proportional fluorescence intensity increase was measured within a 1-10 mM glucose concentration range. Microfluidically synthesized microbeads encapsulating sensing biomolecules offer a quick and low cost method to generate monodisperse biosensors for a variety of applications including cell cultures systems, tissue engineering, etc. V C 2012 American Institute of Physics.

Multiphase Microfluidic Processes to Produce Alginate-Based Microparticles and Fibers

“…Polyethylene glycol diacrylate (PEGDA) is the most common form of PEG used to produce hydrogel particles. An aqueous solution of PEGDA is transformed into hydrogel mainly by using photoinitiators and photocrosslinking processes (Yeh et al, 2006;Kantak et al, 2012;Akbari et al, 2017). In addition to the multiphase process, photocrosslinking technologies with micrometer-sized predefined patterns have been developed to produce particles with highly complicated morphologies, in which living cells have been encapsulated Panda et al, 2008).…”

Hydrogel microparticles for biosensing

“…Indeed, voluminous sensing entities present in the monomer solution may remain captured inside the gel upon crosslinking, if the pore size is small enough. Accordingly, enzymes (horseradish peroxidase (HRP), glucose oxidase (GOx) [66, 67] and concanavalin A [39]) have been encapsulated within PEGDA575 or PEGDA700 particles for glucose sensing applications. Such protocols require tightly crosslinked gels to prevent probe from leaching out, especially in high swelling saline conditions.…”

“…Stream flow-rates and device dimensions control the droplet formation rate and size. For example, Kantak et al used a microfluidic T-junction and UV induced photopolymerization to generate PEG spheres with a 72 μm diameter (Figure 6a) [39]. The spherical particles contained fluorescein isothiocyanate dextran (FITC-dextran) and a sugar binding protein for a fluorescence-based glucose detection assay.…”

“…In 2012, Kantak et al synthesized PEG spheres that contained fluorescein isothiocyanate dextran and tetramethyl rhodamine isothiocyanate conjugated concanavalin A (TRITC-ConA), a sugar binding protein [39]. The TRITC-ConA acted as a quencher, reducing fluorescent signal in the presence of the fluorescein-dextran conjugate.…”

Microfluidic production of single micrometer-sized hydrogel beads utilizing droplet dissolution in a polar solvent

“…In addition, nonspherical beads have been produced by employing photopolymerization-based techniques, such as a) Tel./Fax: þ81-43-290-3398. E-mail: m-yamada@faculty.chiba-u.jp 1932-1058/2013/7(5)/054120/11/$30.00 V C 2013 AIP Publishing LLC 7, 054120-1 stopped-flow lithography, [16][17][18][19][20] scanning-laser lithography, 21 micro-molding, 22 and continuous cross-linking, 23 or by utilizing multiphase microfluidics. 24 These non-spherical beads would be potentially useful as unit structures for fabricating large hydrogel-based constructs by 3D assembly and would also be advantageous for biological encapsulation due to their higher surface-to-volume ratios compared to the spherical beads.…”