Photonic Crystal Beads Research Articles

ZIF-8-CdS photonic crystal beads for slow photon effect induced enhanced photocatalysts

The unique periodic structure of photonic crystals demonstrates an effective slow photon effect that enhances the interaction between light and matter. This study designed and prepared MOF photonic crystal beads, and significantly improved the photocatalytic efficiency by utilizing the slow light effect. Utilizing microfluidic technology, ZIF-8 was self-assembled to form photonic crystal beads (PCB-Z) to enhance adsorption properties and light absorption. The surface of PCB-Z is modified with CdS to form a heterostructure (PCB-ZC), which widens the absorption spectrum, reduces the carrier recombination rate, and increases the specific surface area, while the photocurrent intensity of PCB-ZC is about 1.8 and 29 times that of CdS and PCB-Z. Under the combined effect of photonic crystal structure, ZIF-8/CdS heterojunction and slow photon effect, the degradation rate of Rhodamine B by PCB-ZC was 15.22 times higher than the disordered ZIF-8 powder, and the photocatalytic performance was significantly improved. The dominant role of holes in Rhodamine B degradation was confirmed by free radical trapping experiments and EPR tests. This research confirms that MOF-based photonic crystals can be assembled into periodic structures to enhance adsorption properties and light absorption, which provides a new paradigm for the development of MOF-based photocatalysts.

Confinement Effect Enhanced Bipolar Electrochemistry: Structural Color Coding Coupled with Wireless Electrochemiluminescence Imaging Technology.

In this work, SiO2/CNTs photonic crystal beads were constructed by doping CNTs into SiO2 photonic crystals, which have an angle-independent responsive structural color and can be used as bipolar electrodes due to their good electrical conductivity. In addition, the bipolar electrode-electrochemiluminescence (BPE-ECL) experiments and finite element simulation prove that the low driving voltage can trigger the bipolar electrode electrochemical reactions by confinement effect. Inspired by this, it is the first to combine the SiO2/CNTs structural color coding scheme with low-drive voltage induced wireless BPE-ECL imaging based on the confinement effect of microchannels to achieve simultaneous immune detection of ovarian cancer biomarkers (CA125, CEA, AFP). The detection limits of successfully constructed high-throughput BPE-ECL biosensor for AFP, CEA, and CA125 are 0.72 ng/mL, 0.95 ng/mL, and 1.03 U/mL, respectively, and have good stability and specificity, which expands the application of electrochemiluminescence and lays a foundation for the development of electrochemiluminescence coding technology.

Hierarchical Dendritic Photonic Crystal Beads for Efficient Isolation and Proteomic Analysis of Multiple Cell Types.

Cell types with different morphology, and function collaborate to maintain organ function. As such, analyzing proteomic differences and connections between different types of cells forms the foundation for establishing functional connectomes and developing in vitro organoid simulation experiments. However, the efficiency of cell type isolation from organs is limited by time, equipment, and cost. Here, hierarchical dendritic photonic crystal beads (HDPCBs) featuring high-density functional groups via the self-assembly of dendritic mesoporous structure SiO2 nanoparticles (DM-SiO2) and grafting dendrimers onto the surface of dendritic mesoporous photonic crystal beads (DMPCBs) is developed. This platform integrates multitype cell separation with in situ protein cleavage processes. Efficient simultaneous isolation of Kupffer cells and Liver Sinusoidal Endothelial cells (LSECs) from liver, with high specificity and convenient operation in a short separation time are demonstrated. The results reveal 2832 and 3442 unique proteins identified in Kupffer cells and LSECs using only 50 HDPCBs, respectively. 764 and 629 over-expressed proteins associated with the function of Kupffer cells and LSECs are found, respectively. The work offers a new method for efficiently isolating multiple cell types from tissues and downstream proteomic analysis, ultimately facilitating the identification of primary cell compositions and functions.

Ultrasensitive multiplex SERS immunoassay based on porous Au–Ag alloy nanoparticle–amplified Raman signal probe and encoded photonic crystal beads

An ultrasensitive multiplex surface-enhanced Raman scattering (SERS) immunoassay was developed using porous Au-Ag alloy nanoparticles (p-AuAg NPs) as Raman signal amplification probe coupling with encoded photonic crystal microsphere. p-AuAg NPs were synthesized and modified with the second antibody (Ab2) and Raman tag (mercaptobenzoic acid, MBA) to prepare aRaman signal-amplified probe. The high porosity of the p-AuAg NPs enables significant coupling of the localized surface plasmon resonance and thus abundant inherent hotspots for Raman signal enhancement. 3D-ordered silver nanoparticles-coated silica photonic crystal beads (Ag/SPCBs) were prepared as encoded SERS substrate for multiplex detection using their reflection peaks. Thesignal-amplified probe was used for multiplex detection of tumor markers carcinoembryonic antigen (CEA) and alpha fetoprotein (AFP). The wide linear ranges of 10-7-103ng/mL for CEA and 10-4-103ng/mL for AFP with detection limits of 1.22 × 10-8ng/mL and 2.47 × 10-5ng/mL for CEA and AFP at asignal-to-noise ratio of 3 were obtained. The proposed multiplex SERS immunoassay method displays ultrahigh sensitivity, wide linear range, and excellent specificity, which can be successfully applied to measure clinical serum samples with satisfactory results. The research provides a novel SERS signal enhancement strategy for the multiplex bioassay.

Magnetic-Fluorescent Responsive Janus Photonic Crystal Beads for Self-Destructive Anti-counterfeiting.

In this study, we fabricate magnetic-fluorescent responsive Janus photonic crystal beads (JPCBs) based on poly(styrene-methyl methacrylate-acrylic acid) (p(St-MMA-AA)) colloidal nanoparticles, Fe3O4, and photobase generators used for self-destructive anti-counterfeiting. We synthesize two kinds of photobase generators that can react with fluorescamine to produce various fluorescence colors. A microfluidic method is used to obtain the Janus photonic crystal beads. The upper portions of the JPCBs are photonic crystals assembled with colloidal spheres, whereas the Fe3O4 settles down to the bottom of the JPCBs due to its higher density. Photobase generators are distributed in photonic crystal gaps. Because of the magnetism of the Fe3O4, the JPCBs could be flipped from one side to the other in the presence of a magnet. After being exposed to UVC light and fluorescamine, the JPCBs can fluoresce under UVA light. Then, we create Janus microbeads arrays with various types of beads and apply them to the visitor card, bracelet, and box label to provide irreversible and self-destructive anti-counterfeiting. The JPCBs are capable of being encoded and angle-independently displayed, which are crucial to their applications in anti-counterfeiting, information coding, and array display.

Ultraviolet-magnetic response multicolored janus colloidal photonic crystal beads for information coding

We report a new kind of ultraviolet (UV)-magnetic response Janus colloidal photonic crystal (CPC) beads for information coding. The Janus beads made up of fluorescent CPCs and Fe3O4 nanoparticles show different colors under visible light, UV light and magnetic stimulation. In the concrete scheme, monodisperse colloidal particles with and without fluorescent molecule SPMA were prepared by semi-continuous emulsion polymerization. Then colloidal particles and Fe3O4 nanoparticles were paired as precursors to prepare Janus beads by the droplet template method. During the slow self-assembly process, Fe3O4 nanoparticles were deposited on the bottom and colloidal particles filled the other parts of the beads so that a Janus structure formed. Therefore, the upper surface of Janus beads appears structural color and the lower surface appears black. The variation of Fe content in different hemispheres allows the controllable magnetic response to reverse the beads. The presence of fluorescent molecule SPMA makes fluorescent Janus beads (FJBs) emit fluorescence under UV light. According to design, an array in a particular arrangement of Janus beads can realize reversible changes between three different optical information. Furthermore, the binary cipher was combined with Janus beads to design and fabricate an optical encoding array, revealing an important application in information coding.

Robust structural color beads by self-adhesion amorphous colloidal particles for detection of cerebrospinal fluid biomarkers

Analysis of cerebrospinal fluid (CSF) biomarkers plays a crucial role in prediction and diagnosis of physiological function of brain and neurological diseases. However, due to the lack of extraction volume, especially for mice, it is very difficult to realize multiple biomarkers analysis from the CSF extracted only once. Thus, a novel method with the ability to multiplex analyze mice CSF biomarkers are still anticipated. Here, we proposed a kind of amorphous photonic structure (APS) barcodes using for the multiplex analysis of mice CSF biomarkers. These barcodes were fabricated by assembling easy-to-operated partially adherent polydopamine coated SiO2 nanoparticles (SiO2@PDA NPs), which were derived from a droplet-based microfluidic approach. Owing to adhesion, melanin-like and “active” functional groups of PDA, the obtained APS beads present pigment-like color, robust structure and “active” surface. Moreover, the APS beads possessed close to 13 times coding signal area than the previous spectral coded photonic crystal beads. Besides, through Michael reaction, the APS beads could readily graft the needed biomoleculars. Finally, establishing the animal model of sepsis related encephalopathy and extracting trace amount of CSF from rats’ cisterna magna, three inflammatory cytokines (TNF-α, IL-1β, and IL-6) could be relatively accurate analysis simultaneously using three colored APS beads as barcode carries. These results indicated that the APS barcodes are promising for screening and monitoring many inflammatory related neurological diseases on mice models.

Robust Carbonated Structural Color Barcodes with Ultralow Ontology Fluorescence as Biomimic Culture Platform.

Photonic crystal (PC) barcodes are a new type of spectrum-encoding microcarriers used in multiplex high-throughput bioassays, such as broad analysis of biomarkers for clinical diagnosis, gene expression, and cell culture. Unfortunately, most of these existing PC barcodes suffered from undesired features, including difficult spectrum-signal acquisition, weak mechanical strength, and high ontology fluorescence, which limited their development to real applications. To address these limitations, we report a new type of structural color-encoded PC barcodes. The barcodes are fabricated by the assembly of monodisperse polydopamine- (PDA-) coated silica (PDA@SiO2) nanoparticles using a droplet-based microfluidic technique and followed by pyrolysis of PDA@SiO2 (C@SiO2) barcodes. Because of the templated carbonization of adhesive PDA, the prepared C@SiO2 PC beads were endowed with simultaneous easy-to-identify structural color, high mechanical strength, and ultralow ontology fluorescence. We demonstrated that the structural colored C@SiO2 barcodes not only maintained a high structural stability and good biocompatibility during the coculturing with fibroblasts and tumor cells capture but also achieved an enhanced fluorescent-reading signal-to-noise ratio in the fluorescence-reading detection. These features make the C@SiO2 PC barcodes versatile for expansive application in fluorescence-reading-based multibioassays.

Synthesis of highly ordered AgNPs-coated silica photonic crystal beads for sensitive and reproducible 3D SERS substrates

3D highly ordered silver nanoparticles (AgNPs) coated silica photonic crystal beads (Ag/SPCBs) were prepared and exploited as a novel surface enhanced Raman scattering (SERS) substrate. The monodisperse and size-controlled SPCBs were prepared via self-assembly of silica nanoparticles process using a simple microfluidic device. Then the Ag/SPCBs were easily obtained by in situ growth of AgNPs onto the NH2-modified SPCBs. Field emitting scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDX) were used to characterize the Ag/SPCBs. The effect of silica nanoparticle size and AgNO3 concentration on the SERS performance of the resultant Ag/SPCBs substrate were discussed in detail. The results indicate that the Ag/SPCBs have highest SERS signals when silica nanoparticle size is 250 nm and AgNO3 concentration is 0.8 mg/mL. Using malachite green (MG) as model analyte, the Ag/SPCBs substrate displayed a high sensitivity and a wide linear range for MG. The well-designed Ag/SPCBs show high uniformity and excellent reproducibility, and can be used as an effective SERS substrate for sensitive assay application.

Highly Enhanced Luminescence Performance of LEDs via Controllable Layer‐Structured 3D Photonic Crystals and Photonic Crystal Beads

AbstractControllable layer‐structured 3D photonic crystals (PCs) are prepared using the combination of the Langmuir–Blodgett (LB) technique and layer‐by‐layer stacking method. They are used for research into the influence of the number of the layers on the enhancement of the efficiency of light emission from light‐emitting diodes (LEDs) and quantum dots (QDs). The luminescence properties of blue, green, and white LEDs are improved dramatically while applying such controllable layer‐structured 3D PCs as reflectors and the enhancement efficiencies are shown to increase with PC thickness. In addition, the fluorescence intensity increases 7.8‐fold and 5.4‐fold for red and green QDs, respectively, and the fluorescence intensity can be accurately controlled by using PCs with different layers. In addition, PC beads with yellow and red photonic bandgaps are used to improve the luminescence of a white LED with angle‐independent enhancement. These beads are simply doped into the phosphor without any other treatment. Interestingly, the light intensity of the PC bead based LED is remarkably enhanced. These quantized enhanced effect of light intensity on the thickness of PC layers, along with new generation of PC bead based LED, might offer a strategy for designing high brightness LEDs with energy‐saving performance.

Establishment of a Multivariate Analysis Based on Photonic Crystal Hydrogel Bead Arrays and Its Application for Detecting Platelet-specific Antibodies

ABSTRACTPhotonic crystals are nanomaterials with unique structural coloration, and they have been used in multiple analyses, gene function analyses, and nanoarray biosensors. Here, we used agarose hydrogel microcarriers with characteristic reflection peak codes to improve the biocompatibility of the material and the efficiency of detection, which may be helpful for further clinical applications. The paper has two parts: condition optimization and product application. Goat antihuman immune globulin G, human immune globulin G, and fluorescein isothiocyanate-labeled goat antihuman immune globulin G are commonly used materials in double-antibody sandwich techniques, which are used for optimization in the application of advanced composite materials. Goat antihuman immune globulin G was immobilized on the surfaces of photonic crystal hydrogel beads through chemical bonding. When the target immune globulin G was captured, the fluorescence-labeled antibody could combine with photonic crystal hydrogel beads. The reaction conditions were optimized using the gray-scale value of fluorescent intensities. Photonic crystal hydrogel beads with different reflection spectra were coated with purified platelet glycoprotein IIb/IIIa and glycoprotein Ib/IX. A total of 64 clinical samples including sera from patients with immune thrombocytopenia (n = 32) and healthy human sera (n = 32) were tested using photonic crystal hydrogel beads and monoclonal antibody immobilization of platelet antigen (MAIPA). Photonic crystal hydrogel bead array reaction conditions were established for multiple analysis, showing similar sensitivity and specificity with MAIPA in testing different platelet antibodies and shortening the analysis time. The features of these composite materials make them suitable for potential applications in clinical screening assays.

Low cost 3D microfluidic chips for multiplex protein detection based on photonic crystal beads.

Point-of-care testing (POCT) devices used in multiplex bioassays are in great demand for clinical, environmental and biomedical applications. Photonic crystal beads (PCBs), as structural color self-coding carriers, can be integrated with microfluidic chips to realize convenient and highly sensitive biomarker detection. Here we developed a three dimensional (3D) microfluidic chip based on PCBs, which is low cost and easy to manufacture for mass production and application. The chip was fabricated with polyethylene terephthalate, polymethyl methacrylate sheets, a Ni square mesh grid and transparent double-sided tape. In practice, the target molecules could be captured by PCBs immobilized with probes in a flow-through manner. It was found that the as-proposed chip needed less washing and its background was effectively reduced in comparison with a flow-over chip. Besides, the limit of detection (LOD) of anti-human alpha fetoprotein (AFP) was calculated to be 18.92 ng mL-1, which could meet the need of clinical detection of AFP. Furthermore, the chip demonstrated the feasibility of simultaneous detection of human immunoglobulin G, carcinoembryonic antigen and AFP, which suggests that it has a broad application prospect in multiplex bioassays.

Breath-Taking Patterns: Discontinuous Hydrophilic Regions for Photonic Crystal Beads Assembly and Patterns Revisualization.

Surfaces patterned with hydrophilic and hydrophobic regions provide robust and versatile means for investigating the wetting behaviors of liquids, surface properties analysis, and producing patterned arrays. However, the fabrication of integral and uniform arrays onto these open systems remains a challenge, thus restricting them from being used in practical applications. Here, we present a simple yet powerful approach for the fabrication of water droplet arrays and the assembly of photonic crystal bead arrays based on hydrophilic-hydrophobic patterned substrates. Various integral arrays are simply prepared in a high-quality output with a low cost, large scale, and uniform size control. By simply taking a breath, which brings moisture to the substrate surface, complex hydrophilic-hydrophobic outlined images can be revisualized in the discontinuous hydrophilic regions. Integration of hydrogel photonic crystal bead arrays into the "breath-taking" process results in breath-responsive photonic crystal beads, which can change their colors upon a mild exhalation. This state-of-the-art technology not only provides an effective methodology for the preparation of patterned arrays but also demonstrates intriguing applications in information storage and biochemical sensors.

Ultrasensitive Detection of Protein with Wide Linear Dynamic Range Based on Core-Shell SERS Nanotags and Photonic Crystal Beads.

Detection of proteins in a wide concentration range from fg mL-1 to sub mg mL-1 is a challenge in the high throughput analysis of precision medicine. Herein, we proposed a biosensor consisting of core-shell surface-enhanced Raman scattering (SERS) nanotags as labels and photonic crystal beads (PCBs) as carriers for ultrasensitive detection of proteins. In practice, Raman dyes (RDs) were embedded in the interface of gold core and silver shell in the bimetal nanoparticles to form SERS nanotags. It was found that the sensitivity was significantly improved due to the enhanced Raman signal by the coupling of the core-shell structure and linear dynamic range (LDR) was extended owing to the high surface to volume ratio of PCBs as well. In addition, we also demonstrated that the biosensor exhibited fine stability and low background, which has great application potential in the detection of protein biomarkers.

Preparation of Waterproof Organometal Halide Perovskite Photonic Crystal Beads.

Herein, we report on an innovative method for the preparation of a series of organometal halide perovskite (OHP) photonic crystal beads with pronounced and tunable photonic stop bands by using self-assembled polystyrene spheres as a mold. After infiltration of the mold with OHP precursor solution and slow drying, the OHPs crystallized in the voids of the polystyrene arrays. By controlling the diameter of the polystyrene spheres, the photonic stop band of the OHPs could be precisely tuned. The overlap between the photonic stop band of the beads and the band gap of the OHPs enhances the light harvesting of the perovskite because of the slow photon effect, which arises from the photonic crystal beads. Moreover, the stability of the composite was greatly enhanced by coating with the transparent polymer PDMS without blocking the light propagation. The coated OHP photonic beads kept their composition even after having been in contact with water for 24 h.

Preparation of Waterproof Organometal Halide Perovskite Photonic Crystal Beads

AbstractHerein, we report on an innovative method for the preparation of a series of organometal halide perovskite (OHP) photonic crystal beads with pronounced and tunable photonic stop bands by using self‐assembled polystyrene spheres as a mold. After infiltration of the mold with OHP precursor solution and slow drying, the OHPs crystallized in the voids of the polystyrene arrays. By controlling the diameter of the polystyrene spheres, the photonic stop band of the OHPs could be precisely tuned. The overlap between the photonic stop band of the beads and the band gap of the OHPs enhances the light harvesting of the perovskite because of the slow photon effect, which arises from the photonic crystal beads. Moreover, the stability of the composite was greatly enhanced by coating with the transparent polymer PDMS without blocking the light propagation. The coated OHP photonic beads kept their composition even after having been in contact with water for 24 h.

Hyperspectral imaging analysis of a photonic crystal bead array for multiplex bioassays.

For multiplex bioassays, one effective strategy is to employ microfluidic chips based on an array of photonic crystal beads (PCBs) that are encoded by their characteristic reflection spectrum (CRS). In this paper, we report a hyperspectral imaging system and algorithms for the high throughput decoding of a PCB array and subsequent detection. The results showed that the decoding accuracy of up to ∼500 PCBs is 98.56% with an excellent ability to extract low-intensity fluorescence intensities. The results also demonstrated hyperspectral imaging techniques which can simultaneously obtain both spatial and spectral information as powerful tools in the analysis of multiplex bioassays or microfluidic chips.

Multiplex bioassays encoded by photonic crystal beads and SERS nanotags.

Multiplex bioassays have drawn more and more attention for the development of novel analytical techniques. Herein, we used photonic crystal (PC) and surface enhanced Raman scattering (SERS) as two encoding elements in different modes for the dual encoding of multiplex bioassays. In practice, PC beads and SERS nanotags act as carriers and labels, respectively, for the multiplex detection of antigens in a sandwich format. Except for the amplified capacity by two encoding modes, we also demonstrated that fine stability, low background and high sensitivity were realized for the quantitative analysis of multiple analytes, which holds great promise in biomedical applications like protein biomarker analysis.

3D ordered silver nanoshells silica photonic crystal beads for multiplex encoded SERS bioassay.

3D ordered silver nanoshells silica photonic crystal beads as a novel encoded surface enhanced Raman scattering substrate are proposed for the development of highly efficient multiplex bioassays.

Image decoding of photonic crystal beads array in the microfluidic chip for multiplex assays.

Along with the miniaturization and intellectualization of biomedical instruments, the increasing demand of health monitoring at anywhere and anytime elevates the need for the development of point of care testing (POCT). Photonic crystal beads (PCBs) as one kind of good encoded microcarriers can be integrated with microfluidic chips in order to realize cost-effective and high sensitive multiplex bioassays. However, there are difficulties in analyzing them towards automated analysis due to the characters of the PCBs and the unique detection manner. In this paper, we propose a strategy to take advantage of automated image processing for the color decoding of the PCBs array in the microfluidic chip for multiplex assays. By processing and alignment of two modal images of epi-fluorescence and epi-white light, every intact bead in the image is accurately extracted and decoded by PC colors, which stand for the target species. This method, which shows high robustness and accuracy under various configurations, eliminates the high hardware requirement of spectroscopy analysis and user-interaction software, and provides adequate supports for the general automated analysis of POCT based on PCBs array.