Phase transformation of Sn-based nanowires under electron beam irradiation

One dimensional metal phase change nanomaterials provide a valuable research platform for understanding nanoscale phase transformation behavior and thermal properties, which have potential applications in identification systems such as information storage, barcoding, and detection. Tin(Sn)-based nanowires fabricated using a direct current electrodeposition technique into nanoporous templates are irradiated using electron beam (e-beam) in situ transmission electron microscopy. With the assistance of an oxide shell covering on the Sn-based nanowires, periodic and non-periodic multi-layered nanostructures are precisely sculpted and the reversibility between the original homogeneous alloy phase and the precipitated phases is controllable. The formation mechanism of the phase reversibility and sculpting process also works on other phase change materials, and this was proved using individual SnPb alloy nanowires as a test material. A single Sn–Ag alloy nanowire several microns in length was proved to be easily coded into dozens of morphology/phase statuses, which can be used to produce more than 1000 barcodes. This controllable, phase tunable strategy via selective e-beam irradiation engineering technique is believed to open up a way of sculpting an individual nanowire with various phase statuses and periodicities, which it may be possible to encode into a promising micro–nano identification system with the advantages of ultrahigh capacity, sustainable utilization and good stability

Synergism between particle-based multiplexing and microfluidics technologies may bring diagnostics closer to the patient

In the field of medical diagnostics there is a growing need for inexpensive, accurate, and quick high-throughput assays. On the one hand, recent progress in microfluidics technologies is expected to strongly support the development of miniaturized analytical devices, which will speed up (bio)analytical assays. On the other hand, a higher throughput can be obtained by the simultaneous screening of one sample for multiple targets (multiplexing) by means of encoded particle-based assays. Multiplexing at the macro level is now common in research labs and is expected to become part of clinical diagnostics. This review aims to debate on the “added value” we can expect from (bio)analysis with particles in microfluidic devices. Technologies to (a) decode, (b) analyze, and (c) manipulate the particles are described. Special emphasis is placed on the challenges of integrating currently existing detection platforms for encoded microparticles into microdevices and on promising microtechnologies that could be used to down-scale the detection units in order to obtain compact miniaturized particle-based multiplexing platforms