Table 2 Comparison of applications of 3D printed microfluidic channels

molecule & protein detection

various electrode materials integrated into microchannel; various measurement and functionalities; easy operation in all environments

fabrication complexity with increased number of embedded sensors, large fabrication error width in paper channel

[40, 59, 61, 128, 129]

cell deposition & simulation

at the resolution of individual cells, the possible molecular interactions between cells, 3D concentration of gradients, precise control of fluids, reduced reagent/sample consumption, robust and automated procedure

rather large fluidic channels, discrepancy between the printed and designed channel height

[19, 63,64,65,66,67]

bacterial communities

multiple population, no external force required, little physical damage to cells

hard to predict and control the flow behavior in a channel with varying curvatures, small bacterial concentration in the detection

[68,69,70, 130]

3D tissue constructs

precise control over various cellular microenvironment, easy formation of desired structures, high throughput, reproducible, multi-layer structures

trade-off between cell density of bioink and nozzle size

[51, 74, 78,79,80,81,82, 85,86,87,88, 90, 91]

organ-on-a-chip

accurate position of various tissue samples

throughput is limited by large components with intricate geometries

[15, 17, 92, 118, 131]

organ conformal biopsy

rich diagnostic information, continuous monitoring, direct coupling

unknown long-term effects for human

[94]

Milli- & micro-fluidic reactionware

rapid production and design optimization, quick and versatile material synthesis, high temporal stability

low output volume, inability at high pressure and temperature

[62, 95,96,97]