Baofen Ye

Photonic Crystal Microcapsules for Label‐free Multiplex Detection

A novel suspension array, which possesses the joint advantages of photonic crystal encoded technology, bioresponsive hydrogels, and photonic crystal sensors with capability of full multiplexing label-free detection is developed.

Colorimetric photonic hydrogel aptasensor for the screening of heavy metal ions

We have developed a robust method for the visual detection of heavy metal ions (such as Hg(2+) and Pb(2+)) by using aptamer-functionalized colloidal photonic crystal hydrogel (CPCH) films. The CPCHs were derived from a colloidal crystal array of monodisperse silica nanoparticles, which were polymerized within the polyacrylamide hydrogel. The heavy metal ion-responsive aptamers were then cross-linked in the hydrogel network. During detection, the specific binding of heavy metal ions and cross-linked single-stranded aptamers in the hydrogel network caused the hydrogel to shrink, which was detected as a corresponding blue shift in the Bragg diffraction peak position of the CPCHs. The shift value could be used to estimate, quantitatively, the amount of the target ion. It was demonstrated that our CPCH aptasensor could screen a wide concentration range of heavy metal ions with high selectivity and reversibility. In addition, these aptasensors could be rehydrated from dried gels for storage and aptamer protection. It is anticipated that our technology may also be used in the screening of a broad range of metal ions in food, drugs and the environment.

Free-Standing Photonic Crystal Films with Gradient Structural Colors

Hydrogel colloidal crystal composite materials have a demonstrated value in responsive photonic crystals (PhCs) via controllable stimuli. Although they have been successfully exploited to generate a gradient of color distribution, the soft hydrogels have limitations in terms of stability and storage caused by dependence on environment. Here, we present a practical strategy to fabricate free-standing PhC films with a stable gradient of structural colors using binary polymer networks. A colloidal crystal hydrogel film was prepared for this purpose, with continuously varying photonic band gaps corresponding to the gradient of the press. Then, a second polymer network was used to lock the inside non-close-packed PhC structures and color distribution of the hydrogel film. It was demonstrated that our strategy could bring about a solution to the angle-dependent structural colors of the PhC films by coating the surface with special microstructures.

Aptamer-based suspension array indexed by structural color and shape

A suspension array with microcarriers encoded by both structural color and shape was developed. The microcarriers with high stability, large capacity, low background noise and simplicity for practical application were the hydrogel colloidal crystals fabricated by photolithography. The aptamer based multiplex array, as an example, was constructed using the encoded microcarriers as the carrier of suspension array. The ssDNA functionalized hydrogel microcarriers are achieved by co-polymerization. Based on the high selectivity recognition of aptamer to its target, a novel hydrogel microcarrier suspension array platform, as a potential tool for the efficient quantification of biomolecules, is established.

Non-iridescent structural color pigments from liquid marbles

Structural color pigments have attracted increasing interest in a wide variety of research fields. The color is usually angle dependent and iridescent. However, most applications of the pigments require constant color regardless of the viewing angle. Thus, the development of structural color pigments without iridescence is anticipated. Here, we present novel non-iridescent structural color pigments derived from liquid marble microreactors. Using hydrophobic microparticles to encapsulate colloidal crystal suspension drops in marble microreactors, the resultant pigments have hierarchical micro/nanostructures and ordered colloidal crystal arrays on their surfaces. These structural features impart the structural color pigments with the desired non-iridescence.

Poly-3,4-ethylenedioxythiophene nanoclusters for high effective solid phase extraction.

Solid phase extraction (SPE) has emerged as the widely used technique for sample preparation in the analytical process. Recent research trends of SPE are toward developing novel adsorbents to enrich the analytes simply and effectively. In this study, we proposed the poly-3,4-ethylenedioxythiophene (PEDOT) nanoclusters as the SPE adsorbent. During the application, only a small amount of PEDOT nanoclusters was needed and placed in a pipet tip with glass wool on either side. Without complex preparation, the target analytes could be directly extracted from the sample onto the extraction material and eluted in this lab-in-a-pipet-tip system. The efficiency of this approach was demonstrated by detecting 20 kinds of sulfonamides (SAs) in honey with ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS). All the analytes were detected by multiple reaction monitoring (MRM) mode. The established method was extensively validated by determining the linearity (R(2)≥0.991), average recovery (88.4-105.0%) and precision (relative standard deviation ≤9.60%). Low detection limits (0.5-4 μg kg(-1)), wide linearity (10-250 μg kg(-1)) and short sample pretreatment time (20 min) were achieved under the optimized conditions. The absolute recoveries of the SAs at high level ranged from 71.1% to 91.4%. Due to its simplicity, selectivity and sensitivity, our new method has potential applications in quantitative analysis of the target compounds in complex samples.

CHAPTER 2:Stop‐Bands in Photonic Crystals: From Tuning to Sensing

In this chapter, we first introduced abundant structural colors and variable structural colors in nature. Inspired by the strategies that animals change their structural colors in response to the surrounding environment, our group developed a series of process for constructing tunable photonic crystal by coupling functional molecules, colloidal particle assembly and microfabricating technology. Based on the reversible response of functional molecules, such as photochromic dyes and liquid crystal, not only the stop‐band shift and the intensity change at the stop‐band were realized, but also switchable birefringent photonic crystal and reversible reflection photonic crystal were achieved. Our group also developed novel magnetically tunable photonic crystal, whose stop‐band tuning range covered the entire visible spectrum as well as a fast and fully reversible response. On the other side of tunable photonic crystals, sensing external stimuli by photonic crystals were presented in this chapter. Some physical, chemical and biological sensors was prepared by designing components and structures of photonic crystals in our group.