Liquid Photonic Crystals for Mesopore Detection

Patterned SiO2/Polyurethane Acrylate Inverse Opal Photonic Crystals with High Color Saturation and Tough Mechanical Strength

Patterned structural color photonic crystals (PCs) based on periodic photonic nanostructures have attracted great interest in developing high-performance sensors and other smart optical materials as well as tunable structurally colored fashion textiles. However, previously reported patterned PCs with both high color saturation and tough mechanical strength were difficult to achieve, which restricts their practical applications. Herein, arbitrarily patterned silica/polyurethane acrylate (SiO₂/PUA) inverse opal photonic crystals (IOPCs) with high color saturation and tough mechanical strength were innovatively designed and fabricated by writing with photopolymerizable PUA "ink" on a self-assembled hollow SiO₂ PC template. The high color saturation of the prepared SiO₂/PUA IOPCs originated from the high refractive index contrast between the encapsulated air-filled core and the SiO₂/PUA composite skeleton. The cross-linked flexible PUA matrix tightly warped the self-assembled hollow SiO₂ nanospheres together, endowing the obtained SiO₂/PUA IOPCs a structural color pattern with tough mechanical strength. The structural colors of SiO₂/PUA IOPCs could be finely tuned by regulating their basic parameters, and a redshift in the resultant structural color was observed due to an increase in the lattice constant when increasing the core size and/or shell thickness of the hollow SiO₂ nanospheres.

Hydrophobic Poly(tert-butyl acrylate) Photonic Crystals towards Robust Energy-Saving Performance

Photonic crystals (PCs) have been widely applied in optical, energy, and biological fields owing to their periodic crystal structure. However, the major challenges are easy cracking and poor structural color, seriously hindering their practical applications. Now, hydrophobic poly(tert-butyl acrylate) (P(t-BA)) PCs have been developed with relatively lower glass transition temperature (T_g ), large crack-free area, excellent hydrophobic properties, and brilliant structure color. This method based on hydrophobic groups (tertiary butyl groups) provides a reference for designing new kinds of PCs via the monomers with relatively lower T_g . Moreover, the P(t-BA) PCs film were applied as the photoluminescence (PL) enhanced film to enhance the PL intensity of CdSe@ZnS QDs by 10-fold in a liquid-crystal display (LCD) device. The new-type hydrophobic force assembled PCs may open an innovative avenue toward new-generation energy-saving devices.

A facile fabrication strategy for anisotropic photonic crystals using deformable spherical nanoparticles

A 2D anisotropic photonic crystal (APC) of bowl-shaped nanoparticles has been fabricated using deformable spherical nanoparticles. The prepared 2D isotropic photonic crystal (IPC) of spherical nanoparticles is transformed into a 2D APC by a chemical etching process, in which the interiors of the spherical nanoparticles are preferentially dissolved to eventually form a bowl-like morphology. Due to the accurate and controllable deformability of the spherical nanoparticles, the arrangement and orientations of the bowl-shaped nanoparticles are highly ordered and uniform. The morphology, optical properties and surface wettability of the 2D APC are all distinct from those of the prepared 2D IPC. This facile strategy provides an easy and low-cost way to fabricate highly ordered and uniform APCs.

Bioinspired Production of Noniridescent Structural Colors by Adhesive Melanin-like Particles

Structural color printing of colloidal photonic films with tunable structures or optical properties is of great importance owing to their practical applications. In this article, we present a general method for the fabrication of colloidal particle films with tailored packing geometries by self-assembly of adhesive melanin-like polydopamine (PDA)-coated particles. The adhesion of particles is controlled by varying the thickness of the PDA coating, making it possible for dip coating of colloidal crystals, partly ordered or amorphous colloidal arrays (ACAs) with a tunable degree of order. We further studied the structural color printing of adhesive particles by infiltration-assisted or standard inkjet printing methods. Compared with bare particles, PDA-coated particles not only allow for control over color brightness/angle dependence of the photonic films but also significantly enhance the color quality of ACAs, both of which are useful for display, anticounterfeiting, or sensing applications. Owing to the inherent strong adhesiveness of PDA to virtually all types of surfaces, this PDA-based methodology can be potentially extended to a diverse range of colloidal particles toward the development of photonic devices.

Superwettable colloidal crystal micropatterns on butterfly wing surface for ultrasensitive detection

HYPOTHESIS

Ultrasensitive detections with enrichment approaches based on hydrophilic-hydrophobic patterns have attracted increasing attention in the early diagnosis and treatment of diseases. However, most of these techniques involve complicated micro-fabrications and chemical modifications to achieve their specific pattern substrate wettability. Hence, the development of a simple and effective approach for the construction of new surface wettability techniques for ultrasensitive detection is with great expectations.

EXPERIMENTS

We present a simple approach to fabricate the superwettable colloidal crystal (CC) micropatterns on superhydrophobic Morpho butterfly wing surface for the ultrasensitive detection. The superwettable CC micropatterns were easily obtained by infiltrating and self-assembling monodispersed silica colloidal nanoparticles on the plasma treated butterfly wing patterns. The analytes could be enriched onto the hydrophilic CC area due to the wettability difference between the hydrophilic CC area and the superhydrophobic substrate.

FINDINGS

It was demonstrated that the detection limit of thrombin was down to 1.8 × 10^-13 mol L^-1 based on the fluorophore-labeled aptamer. Moreover, with two-dimensional position codes of these CC micropatterns for different probes, the multiplex detection capability was also demonstrated with great accuracy. As the elimination of complex instruments and chemical modifications, this proposed platform offers a simple strategy for ultrasensitive multiplex detection in practical applications.

Molybdenum disulfide-integrated photonic barcodes for tumor markers screening

As a new class of two-dimensional (2D) materials, molybdenum disulfide (MoS₂) has huge potential in biomedical area; while its applications in multiplex bioassays are still a challenge. Here, we present novel MoS₂-integrated silica colloidal crystal barcode (SCCB) for multiplex microRNA (miRNA) screening. MoS₂ was adsorbed on SCCBs by electrostatic interaction, and quantum dots (QDs) decorated hairpin probes were coupled on MoS₂ by covalent linkage. As the MoS₂ could quench the QDs of the hairpin probes, they together formed a molecular beacon (MB) structure before the detection. When used in assays, target miRNA could form a double strand with the probe and made QDs keep away from MoS₂ sheets to recovery their fluorescence. Because the released QDs were positively correlated with the concentration of the hybridized nucleic acid, the target miRNAs could be quantified by measuring the fluorescence signal of the QDs on the SCCBs. In addition, by utilizing different MoS₂-integrated structural color encoded SCCBs, multiplexed miRNA quantification could also be realized. Based on this strategy, we have demonstrated that several pancreatic cancer-related miRNAs could be selectivity and sensitivity detected with a detection limit of 4.2 ± 0.3 nM. These features make the MoS₂-integrated SCCB ideal for many potential applications.