512-Channel Geometric Droplet-Splitting Microfluidic Device by Injection of Premixed Emulsion for Microsphere Production

Abstract

We present a 512-channel geometric droplet-splitting microfluidic device that involves the injection of a premixed emulsion for microsphere production. The presented microfluidic device was fabricated using conventional photolithography and polydimethylsiloxane casting. The fabricated microfluidic device consisted of 512 channels with 256 T-junctions in the last branch. Five hundred and twelve microdroplets with a narrow size distribution were produced from a single liquid droplet. The diameter and size distribution of prepared micro water droplets were 35.29 µm and 8.8% at 10 mL/h, respectively. Moreover, we attempted to prepare biocompatible microspheres for demonstrating the presented approach. The diameter and size distribution of the prepared poly (lactic-co-glycolic acid) microspheres were 6.56 µm and 8.66% at 10 mL/h, respectively. To improve the monodispersity of the microspheres, we designed an additional post array part in the 512-channel geometric droplet-splitting microfluidic device. The monodispersity of the microdroplets prepared with the microfluidic device combined with the post array part exhibited a significant improvement.

Blood Particulate Analogue Fluids: A Review

“…In the same way, as in the case of PMMA particles, the rigidity of PS particles makes them unsuitable to mimic the behaviour of RBCs. Figure 1 j 512-channel geometric droplet-splitting microfluidic device combined with a post array part [ 51 ]: (I) premixing solutions, dispersed phase (PLGA dissolved in dimethyl carbonate, DMD, at 2 wt%) and continuous phase (polyvinyl alcohol, PVA, dissolved in deionized water at 2 wt%), (II) injection of premixed emulsion through the device, and (III) collection under stirring to remove solvent from the microspheres, satellites were filtered during the collection process by using a sieve. The droplets were polymerized/solidified by the evaporation of the solvent, resulting in spherical PLGA particles of around 9 μm in diameter.…”

“…Figure 2 j shows SEM images of PDMS (10:1) microparticles produced using the two-syringe membrane emulsification, (1) before and (2) and (3) after being cut by an ion beam for obtaining the cross-section [ 50 ]. Finally, Figure 2 k presents SEM image of PLGA microparticles produced using 512-channel geometric droplet-splitting microfluidic device combined with a post array part [ 51 ].…”

“…In spite of the deformability of the spherical PLGA RBC template proposed in Ref. [ 51 ] not being assessed, it is expected to be insignificant because E ≈ 4300 MPa. Finally, in the case of the Brij L4 micelles [ 59 ], the authors examined the DI of these RBC templates by using a device similar to that showed in Figure 3 d. The micelles DI was similar to that of RBCs, a little bit lower than that of RBCs in the contraction region, 0.21 vs. 0.26, respectively.…”

“… Production methods of RBC templates: ( a ) electrohydrodynamic jetting [ 33 , 34 ], ( b ) stop flow lithography (SFL) [ 35 , 36 ], ( c ) PRINT ® [ 37 , 38 ], ( d ) Layer-by-Layer [ 40 , 41 , 42 ], ( e ) [ 43 ], ( f ) liquid–liquid flow-focusing with a hypodermic needle [ 44 , 45 , 46 ], ( g ) electrospray with solvent diffusion [ 47 ], ( h ) lipid film hydration [ 48 , 49 ], ( i ) two-syringe membrane emulsification [ 50 ], ( j ) 512-channel geometric droplet-splitting microfluidic device combined with a post array part [ 51 ], and ( k ) premix membrane emulsification [ 52 ]. Roman numerals are used to explain, in the text, the main steps for each production method.…”

“… Images of microparticles (RBC templates) produced by using methods from Figure 1 : ( a ) electrohydrodynamic jetting [ 34 ], ( b ) stop flow lithography (SFL) [ 35 ], ( c ) PRINT ® [ 37 ], ( d ) electrohydrodynamic (electrospraying) [ 39 ], ( e ) layer-by-Layer from solid template (LbL) [ 41 ], ( f ) LbL from porous template [ 42 ], ( g ) [ 43 ], ( h ) liquid–liquid flow-focusing with a hypodermic needle [ 44 ], ( i ) electrospray with solvent diffusion [ 47 ], ( j ) two-syringe membrane emulsification [ 50 ], and ( k ) 512-channel geometric droplet-splitting microfluidic device combined with a post array part [ 51 ]. Scale bars are 5 μm in ( a , d -(2), e , g , h ), 10 μm in ( b , c , f , h , j , k ), and 50 μm in ( d – 1 ).…”