Search for: All records

Abstract Shrink lithography is a promising top‐down micro/nanofabrication technique capable of miniaturizing patterns/structures to scales much smaller than the initial mold, however, rapid inexpensive fabrication of high‐fidelity shrinkable microfeatures remains challenging. This work reports the discovery and characterization of a simple, fast, low‐cost method for replicating and miniaturizing intricate micropatterns/structures on commodity heat‐shrinkable polymers. Large‐area permanent micropatterning on polystyrene and polyolefin shrink film is attained in one step under ambient conditions through brief irradiation by a shortwave UV pencil lamp. After baking briefly in an oven, the film shrinks biaxially and the miniaturized micropatterns emerge with significantly reduced surface area (up to 95%) and enhanced depth profile. The entire UV‐micropatterned miniaturization process is highly reproducible and achievable on benchtop under a few minutes without chemicals or sophisticated apparatus. A variety of microgrid patterns are replicated and miniaturized with high yield and resolution on both planar and curved surfaces. Sequential UV exposures enable easy and rapid engineering of sophisticated microtopography with miniaturized, multiscale, multidimensional microstructures. UV–ozone micropatterned polystyrene surfaces are well‐suited for lab‐on‐a‐chip analytical applications owing to the inherent biocompatibility and enhanced surface hydrophilicity. Miniaturization of dense, periodic micropatterns may facilitate low‐cost prototyping of functional devices/surfaces such as micro‐optics/sensors and tunable metamaterials. 

Abstract DNA devices have been shown to be capable of evaluating Boolean logic. Several robust designs for DNA circuits have been demonstrated. Some prior DNA‐based circuits are use‐once circuits since the gate motifs of the DNA circuits get permanently destroyed as a side effect of the computation, and hence cannot respond correctly to subsequent changes in inputs. Other DNA‐based circuits use a large reservoir of buffered gates to replace the working gates of the circuit and can be used to drive a finite number of computation cycles. In many applications of DNA circuits, the inputs are inherently asynchronous, and this necessitates that the DNA circuits be asynchronous: the output must always be correct regardless of differences in the arrival time of inputs. This paper demonstrates: 1) renewable DNA circuits, which can be manually reverted to their original state by addition of DNA strands, and 2) time‐responsive DNA circuits, where if the inputs change over time, the DNA circuit can recompute the output correctly based on the new inputs, that are manually added after the system has been reset. The properties of renewable, asynchronous, and time‐responsiveness appear to be central to molecular‐scale systems; for example, self‐regulation in cellular organisms.