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 DPAA 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 DPEG-PAA rich in amino and hydroxyl groups, respectively. The fabricated device D-PAA possessed superior printing accuracy (40-50 mu m). Functionalization of amino and hydroxyl was successful, and the modified devices DPDA-PAA and DPEG-PAA maintained a high thermal stability like DPAA. Surface potential analysis and molecular dynamics simulation indicated that the affinity for DNA was in the order of DPDA-PAA > DPEG-PAA > D-PAA. Further DNA separation experiments confirmed the high throughput and high selectivity of DNA separation performance, consistent with the predicted affinity results. DPDA-PAA showed relatively the highest DNA extraction yield, while DPEG-PAA was the worst. An acidic binding system is more favorable for DNA separation and recovery. DPDA-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.