Integrated Three-Dimensional Microdevice with a Modified Surface for Enhanced DNA Separation from Biological Samples.

Functional interfaces and devices for rapid adsorption and immobilization of nucleic acids (NAs) are significant for relevant bioengineering applications. Herein, a microdevice with poly(acrylic acid) (PAA) photosensitive resin was integrated by three-dimensional (3D) printing, named D PAA for short. Precise microscale structures and abundant surface carboxyl functional groups were fabricated for fast and high-throughput deoxyribonucleic acid (DNA) separation. Surface modification was then done using polydopamine (PDA) and poly(ethylene glycol) (PEG) to obtain modified poly(acrylic acid) (PAA)-based devices D PDA-PAA and D PEG-PAA rich in amino and hydroxyl groups, respectively. The fabricated device D PAA possessed superior printing accuracy (40-50 μm). Functionalization of amino and hydroxyl was successful, and the modified devices D PDA-PAA and D PEG-PAA maintained a high thermal stability like D PAA . Surface potential analysis and molecular dynamics simulation indicated that the affinity for DNA was in the order of D PDA-PAA > D PEG-PAA > D PAA . Further DNA separation experiments confirmed the high throughput and high selectivity of DNA separation performance, consistent with the predicted affinity results. D PDA-PAA showed relatively the highest DNA extraction yield, while D PEG-PAA was the worst. An acidic binding system is more favorable for DNA separation and recovery. D PDA-PAA showed significantly better DNA extraction performance than D PAA in a weakly acidic environment (pH 5.0-7.0), and the average DNA yield of the first elution was 2.16 times that of D PAA . This work validates the possibility of modification on integrated 3D microdevices to improve their DNA separation efficiency effectively. It also provides a new direction for the rational design and functionalization of bioengineering separators based on nonmagnetic methods. It may pave a new path for the highly efficient polymerase chain reaction diagnosis.