An unclonable, fingerprint-mimicking anti-counterfeiting strategy is presented that encrypts polymeric particles with randomly generated silica film wrinkles. The generated wrinkle codes are as highly unique as human fingerprints and are technically irreproducible. Superior to previous physical unclonable functions, codes are tunable on demand and generable on various geometries. Reliable authentication of real-world products that have these microfingerprints is demonstrated using optical decoding methods.

We developed a new microfluidic method for focusing microparticles through the combined use of inertial lift forces and turbulent secondary flows generated in a topographically patterned microchannel. The mechanism of particle focusing is based on the hydrodynamic inertial forces exerted on particles migrating along a non-circular microchannel, i.e.tubular pinch effect and wall effect, which induce particle movement away from walls and along a specific lateral position in the microchannel. With the extraordinary geometry of multi-orifice microchannel, an ordered and focused particle distribution was achieved at central or side regions according to a particle Reynolds number (Re(p)) range. The focusing of particles was controlled by the particle Reynolds number, microchannel length, and volume fraction of particles in suspension. This method will be beneficial in particle focusing processes in a microfluidic device since it offers continuous, high-throughput performance and simple operation.

In this article, we introduce a rapid and simple fabrication method to realize a 3-dimensional (3-D) microfluidic channel with a near-perfect circular cross section. This new concept of fabrication method is defined by metal wire removal process, where the metal wire such as a thin soldering wire for the 3-D circular shape is commercially available. For the microfluidic channel mold, PDMS (polydimethylsiloxane) was poured on several shapes such as 3-D circular, helix, and double helix shapes, of soldering wire and solidified. The soldering wire was then melted out by heating. With the two-step process, rapidly and simply fabricated 3-D circular microfluidic channels can be obtained. CPAE (endothelial cell line) cells were cultured inside the channel to evaluate the biocompatibility of the fabricated microfluidic channel. Our method will be very useful in making various circular shapes of 3-D microfluidic devices that need multi-depth and round corners inside the channel.

Inductively coupled planar resonators offer convenient integration of high-resolution NMR spectroscopy with microfluidic lab-on-a-chip devices. Planar spiral resonators are fabricated lithographically either by gold electroplating or by etching Cu laminated with polyimide. Their performance is characterized by NMR imaging as well as spectroscopy. A single-scan limit of detection LOD(t) = 0.95 nmol s(1/2) was obtained from sample volumes around 1 μL. The sensitivity of this approach is similar to that obtained by microstripline and microslot probes.

DNA-based data storage has emerged as a promising method to satisfy the exponentially increasing demand for information storage. However, practical implementation of DNA-based data storage remains a challenge because of the high cost of data writing through DNA synthesis. Here, we propose the use of degenerate bases as encoding characters in addition to A, C, G, and T, which augments the amount of data that can be stored per length of DNA sequence designed (information capacity) and lowering the amount of DNA synthesis per storing unit data. Using the proposed method, we experimentally achieved an information capacity of 3.37 bits/character. The demonstrated information capacity is more than twice when compared to the highest information capacity previously achieved. The proposed method can be integrated with synthetic technologies in the future to reduce the cost of DNA-based data storage by 50%.