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In recent years, suspension arrays,[1] which use self-encoded microcarriers as elements, are attracting increasing interest in the field of drug discovery, gene-function analysis, clinical diagnosis, and so on.[2–7] Compared with the conventional microarrays on a plate,[8, 9] suspension arrays may offer greater flexibility in the preparation of new assays, higher diffusional flux of analytes due to the radial diffusion, less consumption of sample and reagents, and higher sensitivity.[1] One of the key techniques of suspension arrays is encoding. Spectrum is a wellused encoding approach, due to its simplicity both in encoding and decoding. Fluorescent dyes [10–12] and quantum dots [13–15] are the main spectrum-encoding elements, and the beads encoded by fluorescence have been commercialized by Luminex and other companies. However, fluorescence dyes tend to be quenched or bleached, and the quantum dots are usually biotoxic. Also, the fluorescence of the carriers can interfere with the signal from the labeling molecules, and as a result affect the detection limit. Photonic crystals have been suggested as a new type of spectrum-encoding carrier, whose code is the characteristic reflection peak originated from the stop-band.[16] As the peak position is based on their periodical structure, the code is very stable, and the fluorescent background is low. These properties render photonic crystals suitable for highly sensitive detection. Conventional planar photonic-crystal carriers have to be properly dispersed and correctly orientated to avoid stacking or standing of the flakes during the decoding process. Recently, we found that these problems might …