As
molecular computing materials, information-encoded deoxyribonucleic
acid (DNA) strands provide a logical computing process by cascaded
and parallel chain reactions. However, the reactions in DNA-based
combinational logic computing are mostly achieved through a manual
process by adding desired DNA molecules in a single microtube or a
substrate. For DNA-based Boolean logic, using microfluidic chips can
afford automated operation, programmable control, and seamless combinational
logic operation, similar to electronic microprocessors. In this paper,
we present a programmable DNA-based microfluidic processing unit (MPU)
chip that can be controlled via a personal computer
for performing DNA calculations. To fabricate this DNA-based MPU,
polydimethylsiloxane was cast using double-sided molding techniques
for alignment between the microfluidics and valve switch. For a uniform
surface, molds fabricated using a three-dimensional printer were spin-coated
by a polymer. For programming control, the valve switch arms were
operated by servo motors. In the MPU controlled via a personal computer or smartphone application, the molecules with
two input DNAs and a logic template DNA were reacted for the basic
AND and OR operations. Furthermore, the DNA molecules reacted in a
cascading manner for combinational AND and OR operations. Finally,
we demonstrated a 2-to-1 multiplexer and the XOR operation with a
three-step cascade reaction using the simple DNA-based MPU, which
can perform Boolean logic operations (AND, OR, and NOT). Through logic
combination, this DNA-based Boolean logic MPU, which can be operated
using programming language, is expected to facilitate the development
of complex functional circuits such as arithmetic logical units and
neuromorphic circuits.