Fast prototyping microfluidics: integrating Digital LAMP for evaluation
of gene expression
Abstract
Microfluidics (MF) is becoming the next step of integrated platforms for
molecular diagnostics, where isothermal schemes allow further
simplification of DNA detection and quantification protocols. MF for
loop-mediated isothermal amplification (LAMP) is today the focus of a
new generation of chip-based devices for molecular detection towards
fast and automated nucleic acid quantification. Here, we integrated MF
and digital droplet LAMP (ddLAMP) on a chip that allows droplet
generation, amplification and target quantification. This multilayer 3D
chip is produced using a low-cost and extremely adaptable production
process using direct laser writing technology in Shrinky-dinks
polystyrene plastic sheets in less than 30 minutes. ddLAMP and target
quantification were performed directly on chip showing a high
correlation between target concentration and positive droplet score. We
validate this ddLAMP integrated chip via the amplification of targets
between 5 and 500,000 copies/reaction under 60 min. Moreover, on-chip
ddLAMP was performed in a 10 µL volume, with a limit of detection of 5
copies/µL of target. This technology was applied to quantify a cancer
biomarker, c-MYC, but it can be further extended to any other disease
biomarker.