Colloidal crystals (CCs) are ordered arrays of monodisperse colloidal particles. Because of the presence of a periodic superlattice of colloids and voids, CCs bear many unique structures and fascinating properties which are distinctly different from those of standard crystals with atoms, ions or molecules as repeating subunits. The research on CCs has surprisingly blossomed during recent decades, and many practical materials based on CCs with potential applications in photonic devices, material science and biomedical engineering have been generated. In this review, we give a systematic, balanced and comprehensive summary of the main aspects of CCs related to their preparation and application, and propose perspectives for the future developments of CCs.

Conductive photodefinable polydimethylsiloxane (PDMS) composites that provide both high electrical conductivity and photopatternability have been developed. The photosensitive composite materials, which consist of a photosensitive component, a conductive filler, and a PDMS pre‐polymer, can be used as a negative photoresist or a positive photoresist with an additional curing agent. A standard photolithographic approach has been used to fabricate conductive elastomeric microstructures. Feature sizes of 60 µm in the positive photoresist and 10 µm in the negative photoresist have been successfully achieved. Moreover, as the conductive filler, silver powders significantly improve the electrical conductivity of the PDMS polymer, but also provide enhanced mechanical and thermal properties as well as interesting biological properties. The combined electrical, mechanical, thermal, and biological properties along with photopatternability make the PDMS‐Ag composite an excellent processable and structural material for various microfabrication applications.

Monodispersed copolymer latex particles functionalized by surface carboxylate groups are used as effective colloidal templates for the controlled crystallization of calcium carbonate in solution. After template removal, well-defined, calcite single crystals exhibiting a rhombohedral morphology and uniform surface pores are obtained. The surface pore size of the calcite single crystals can be readily adjusted through introduction of latex particles with varied sizes. The effects of the surface functional groups of the latexes, the concentration of the latex dispersion and CaCl 2 solution and the temperature during the CaCO 3 crystallization have been investigated. A three-step mechanism has been proposed for the formation of the composite particles consisting of calcite single crystals and latex particles, and it has been demonstrated that this synthesis strategy is potentially extendable to the synthesis of regularly shaped composite particles consisting of single crystals of other inorganic materials, such as Cu 2 O. In addition, surface-patterned calcite crystals with hierarchical architectures are prepared at a relatively high concentration of latex particles, which act as both colloidal templates and crystal growth modifiers.

Nanoparticles have been developed for tumor treatment due to the enhanced permeability and retention effects. However, lack of specific cancer cells selectivity results in low delivery efficiency and undesired side effects. In that case, the stimuli-responsive nanoparticles system designed for the specific structure and physicochemical properties of tumors have attracted more and more attention of researchers. Esterase-responsive nanoparticle system is widely used due to the overexpressed esterase in tumor cells. For a rational designed esterase-responsive nanoparticle, ester bonds and nanoparticle structures are the key characters. In this review, we overviewed the design of esterase-responsive nanoparticles, including ester bonds design and nano-structure design, and analyzed the fitness of each design for different application. In the end, the outlook of esterase-responsive nanoparticle is looking forward.

An extensive family of oxide cluster fullerenes (OCFs) Sc 2 O@C 2n (n=35-47) has been facilely produced for the first time by introducing CO 2 as the oxygen source. Among this family, Sc 2 O@C 70 was identified as the smallest OCF and therefore isolated and characterized by mass spectrometry, 45 Sc NMR, UV-Vis-NIR absorption spectroscopy, cyclic voltammetry and DFT calculations. The combined experimental and computational studies reveal a non-IPR isomer 5 Sc 2 O@C 2 (7892)-C 70 with reversible oxidative behavior and lower bandgap relative to that of Sc 2 S@C 2 (7892)-C 70 , demonstrating a typical example of unexplored OCF and underlining its clusterdependant electronic properties.