Silica Colloidal Crystal Beads Research Articles

Chitosan-based fluorescent inverse opal particles for Cr(VI) sensing

Chitosan (CS) is a natural polymer widely used in many fields. However, there are seldom studies that focus on its inherent fluorescence properties. In this work, based on the inherent fluorescence of chitosan (CS) and the mechanism that it can be quenched by hexavalent chromium (Cr(VI)), we developed novel CS-based inverse opal particles (IOPs) for Cr(VI) detection. The CS IOPs were obtained by replicating the silica colloidal crystal beads using CS, which displayed uniform shape and size, as well as enhanced fluorescence-emission capability resulted from the unique microstructure. Under the optimized conditions, the CS IOPs responded to Cr(VI) in a range of 0–10,000 μM with high sensitivity and specificity and demonstrated a LOD of 0.055 μM at the linear range of 0–30 μM. Furthermore, they displayed good detection ability in practical applications with recoveries of 86–106% for tap water and 99.7–107.3% for pond water, respectively. With these features, the developed CS IOPs are promising to be a simple, low-cost, and fast platform for detecting Cr(VI).

Black phosphorus quantum dots doped multifunctional hydrogel particles for cancer immunotherapy

Immunotherapy is a powerful approach for oncotherapy that relies on enhancing the ability of the immune system to recognize and attack tumors. Effectively provoking the immune effector cells to respond to cancer cells is still a challenge. Here, we present a novel kind of γδ T cell-stimulating hydrogel particle loaded with zoledronate for breast cancer immunotherapy. The hydrogel particles with interconnected nanopores were formed by negatively replicating silica colloidal crystal beads (SCCBs) through using N-isopropylacrylamide (NIPAM) pregel solution doped with black phosphorus quantum dots (BPQDs). Due to the photothermal-responsive property of the BPQDs doped pNIPAM hydrogel, the releasing of zoledronate from these particles could be accurately controlled by using deep penetrating near-infrared (NIR) light. Owing to the direct anti-tumor activity and the capacity of stimulating γδ T-cell to attack tumor cells, our BPQDs-doped pNIPAM hydrogel particles show great potential for γδ T cell activation and proliferation with high therapeutic efficacy for in vivo breast cancer treatment. Thus, the γδ T cell-stimulating hydrogel particles provide a novel clinical treatment option for cancer immunotherapy.

Oriented boronate affinity-imprinted inverse opal hydrogel for glycoprotein assay via colorimetry.

A biomimetic antibody is described for colorimetric determination of glycoprotein, and horseradish peroxidase (HRP) is used as model analyte. Use is madeof oriented surface imprinted inverse opal hydrogel particles functionalized with phenylboronic acid. The inverse opal hydrogel particles were negatively replicated from silica colloidal crystal beads (SCCBs), so that they were endowed with larger specific surface area than the bulk structure. Benefit from that, there were abundant surface molecularly imprinting sites in the hydrogel particles. Because the imprinting sites match the structure of the template molecules, they can recognize HRP with high selectivity and sensitivity. The recognized glycoprotein was bonded with the phenylboronic acid within the sites. The bonded HRP was determined by colorimetry of 3, 3', 5, 5'-tetramethylbenzidine (TMB) single-component solution at 450nm, and it shows a 16.03 imprinting factor underoptimized conditions. Alpha-fetoprotein (AFP) wasalso investigated and demostrated the value of this strategy in practical applications. The results show that the absorbance increases linearly in the 1-50ngmL-1 AFP concentration range and has a 1.32ngmL-1 detection limit. The assay of human serum was realized by the standard addition method. This strategy is promising to open new horizons for glycoprotein assay. Graphical abstract Schematic representation of the preparation of oriented boronate affinity-imprinted inverse opal hydrogel particles for glycoprotein assay.

P‐Glycoprotein Antibody Decorated Porous Hydrogel Particles for Capture and Release of Drug‐Resistant Tumor Cells

Multidrug resistance is one of the leading causes of chemotherapy failure in cancer patients. Early detection and capture of drug-resistant tumor cells can facilitate the monitoring of the therapy process and improve the prognosis of patients. In this study, novel P-glycoprotein (P-gp) antibody modified porous hydrogel particles are proposed for drug-resistant tumor cells capture. The hydrogel particles employ a highly biocompatible hydrogel, methacrylate gelatin (GelMA), as the carrier and replicate from the silica colloidal crystal beads. By the modification of P-gp antibody probes on their surfaces, the hydrogel particles are endowed with the ability to capture drug-resistant tumor cells, which overexpress specific components of P-gp on their membranes. Additionally, the acquired ordered porous nanostructure of the particles can provide not only more surface area for antibody immobilization but also a nanopatterned platform for highly efficient target cell capture. The above advantages make the porous hydrogel particles ideal for efficient capture and detection of the drug-resistant tumor cells, which can be expected to facilitate the point-of-care pharmacotherapy and promisingly improve the patient outcomes.

Responsive photonic encoded breathing microbeads based microfluidic chip for multiplex fluorescent immunoassay

Suspension array attracted much attention around the world because of its benefits in simultaneous analysis of multiple targets. Photonic crystal encoded beads array was a type of optical encoded suspension array technology. Microbead with opal structure, named as silica colloidal crystal beads (SCCBs), was the most frequently used carrier in immunoassay previously, while microbead with inverse opal structure was used in molecular imprinting assay or label-free detection. However, inverse opal structure makes microcarrier to have larger specific surface area; and such structure makes microcarrier to have transformable dimension. With both characteristics, inverse opal structure microbead is more competent for fluorescent immunoassay compared with SCCB. Here a solvent responsive photonic encoded microbead with inverse opal structure, also named as responsive breathing microbead, was prepared, and simultaneously integrated with a special designed microfluidic chip, its excellent performance in multiplex fluorescent immunoassay was presented.

Simultaneous Detection of Fenitrothion and Chlorpyrifos-Methyl with a Photonic Suspension Array

A technique was developed for simultaneous detection of fenitrothion (FNT) and chlorpyrifos-methyl (CLT) using a photonic suspension array based on silica colloidal crystal beads (SCCBs). The SCCBs were encoded with the characteristic reflection peak originating from the stop-band of colloidal crystal. This approach avoids the bleaching, fading or potential interference seen when encoding by fluorescence. SCCBs with a nanopatterned surface had increased biomolecule binding capacity and improved stability. Under optimal conditions, the proposed suspension array allowed simultaneous detection of the selected pesticides in the ranges of 0.25 to 1024 ng/mL and 0.40 to 735.37 ng/mL, with the limits of detection (LODs) of 0.25 and 0.40 ng/mL, respectively. The suspension array was specific and had no significant cross-reactivity with other chemicals. The mean recoveries in tests in which samples were spiked with target standards were 82.35% to 109.90% with a standard deviation within 9.93% for CLT and 81.64% to 108.10% with a standard deviation within 8.82% for FNT. The proposed method shows a potentially powerful capability for fast quantitative analysis of pesticide residues.

Glioma markers detection and assessment based on a photonic suspension array

A new multiplex glioma marker immunoassay was developed based on a photonic suspension array. The micro-carriers of this array were silica colloidal crystal beads (SCCBs). As the code of the micro-carriers is the characteristic reflection peak originating from the stop-band of the colloid photonic crystal, they could effectively avoid photo-bleaching, the potential interference of encoding fluorescence with analyte-detection fluorescence and chemical instability. Meanwhile, the fluorescence background of the SCCBs is very low, because no dyes or materials with related fluorescence are included. The proposed suspension array was used for simultaneous multiplex detection of three glioma markers in one test tube by forming a sandwich immunocomplex on the SCCBs. The results showed that the three markers, Bcl-2 protein, cyclinD1 and p21, could be assayed in the ranges of 10–180 ng ml−1, 0.1–13.5 ng ml−1, 0.053–0.9 ng ml−1, with limits of detection of 1 ng, 0.1 ng, 0.053 ng at 3σ, respectively. The proposed array has also shown storage stability and accuracy for sample detection. This technique provides a new strategy for low cost, automated, and simultaneous multiplex immunoassay.

Multiplex Detection of B-Type Natriuretic Peptide, Cardiac Troponin I and C-Reactive Protein with Photonic Suspension Array

A novel photonic suspension array has been developed for multiplex immunoassay. The carriers of this array were silica colloidal crystal beads (SCCBs). The codes of these carriers have characteristic reflection peaks originating from their structural periodicity; therefore they do not suffer from fading, bleaching, quenching or chemical instability. In addition, the fluorescence background of SCCBs is negligible because no fluorescence materials or dyes are involved. With a sandwich method, the proposed suspension array was used for simultaneous multiplex detection of heart failure (HF) and coronary heart disease (CAD) biomarkers in one test tube. The results showed that the three biomarkers: cardiac troponin I (cTnI), C-reactive protein (CRP) and B-type natriuretic peptide (BNP) could be assayed in the ranges of 0.1–500 ng/ml, 1–500 mg/L and 0.02–50 ng/ml with detection limits of 0.01 ng/ml, 0.36 mg/L and 0.004 ng/ml at 3σ, respectively. There were no significant differences between the photonic suspension array and traditional parallel single-analyte test. This novel method demonstrated acceptable accuracy, high detection sensitivity and reproducibility and excellent storage stability. This technique provides a new strategy for low cost, automated, and simultaneous multiplex immunoassays of bio-markers.

Multiplex analysis of tumor multidrug-resistance genes expression with photonic suspension array

An easy-operated suspension array based on silica colloidal crystal beads is developed for multiplex analysis of tumor multidrug-resistance genes expression, such as multidrug resistance 1 (MDR1) and multidrug resistance-associated protein 1 (MRP1), and potentially single nucleotide polymorphism. In order to obtain high fluorescence intensity, controlled PCR was used to amplify targets at the samples pretreatment stage. By optimizing the conditions a hybridization procedure, which is similar to nucleic acids analysis with binary probes, was established. Small amounts of analytes 10(-19) M could be detected by the method. The K562 cell, human myeloma cell, and its multidrug-resistance string, adriamycin-selected P-glycoprotein-overexpressed K562/A02, were analyzed by using an established procedure to validate feasibility. Clinical blood samples were detected by our method and real-time PCR simultaneously to validate accuracy. Moreover, when combined with multiplex controlled PCR, the method successfully meets the requirements of multiplex analysis. Hence, the method presented is a good method for multiplex analysis of tumor multidrug-resistance genes expression.

Multiplex tumor marker detection with new chemiluminescent immunoassay based on silica colloidal crystal beads

A new multiplex chemiluminescent immunoassay (CLIA) based on silica colloidal crystal beads (SCCBs) was developed for tumor marker detection. As the code is the characteristic reflection peak originating from the stop-band of colloid crystal, they avoid photobleaching, the potential interference of encoding fluorescence with analyte-detection fluorescence and chemical instability. Meanwhile our SCCBs suspension array improved the luminescence analysis efficiency by using chemiluminescent detection of enzyme labels. By forming a sandwich immunocomplex on SCCBs, the proposed suspension array was used for simultaneous multiplex detection of tumor markers in one test tube. The results showed that the linear range was 0.5-100ng ml(-1) and 1.0-120ng ml(-1) for carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) with a detection limit of 0.12ng ml(-1) and 0.16ng ml(-1) at 3sigma. The proposed array showed the storage stability and the accuracy for sample detection were acceptable, and the results were in acceptable agreement with the reference electrochemiluminescence method. This technique provided an automated, simple, sensitive and low-cost approach for multianalyte immunoassay.

Packing the Silica Colloidal Crystal Beads: A Facile Route to Superhydrophobic Surfaces

To mimic the structure of the lotus leaf, we present a facile route to prepare superhydrophobic surfaces by depositing nanoparticle clusters onto a solid surface. These clusters were fabricated via solidification of an emulsion droplet containing a nanoparticle in silicone oil. Thus, the microsized clusters and nanoparticles form dual-scale roughness structures. The surface is modified by fluoroalkylsilane and exhibits superhydrophobicity, with a contact angle greater than 165 degrees as well as a sliding angle less than 1 degrees . On the basis of size tuning of the nano/microstructures, various contact angles and sliding angles were investigated. Furthermore, the influence of micro/nanostructures on superhydrophobicity is discussed.

Multiplex detection of tumor markers with photonic suspension array

A novel photonic suspension array was developed for multiplex immunoassay. The carries of this array were silica colloidal crystal beads (SCCBs). The codes of these carriers are the characteristic reflection peak originated from their structural periodicity, and therefore they do not suffer from fading, bleaching, quenching, and chemical instability. In addition, because no dyes or materials related with fluorescence are included, the fluorescence background of SCCBs is very low. With a sandwich format, the proposed suspension array was used for simultaneous multiplex detection of tumor markers in one test tube. The results showed that the four tumor markers, α-fetoprotein (AFP), carcinoembryonic antigen (CEA), carcinoma antigen 125 (CA 125) and carcinoma antigen 19-9 (CA 19-9) could be assayed in the ranges of 1.0–500 ng mL −1, 1.0–500 ng mL −1, 1.0–500 U mL −1 and 3.0–500 U mL −1 with limits of detection of 0.68 ng mL −1, 0.95 ng mL −1, 0.99 U mL −1 and 2.30 U mL −1 at 3 σ, respectively. The proposed array showed acceptable accuracy, detection reproducibility, storage stability and the results obtained were in acceptable agreement with those from parallel single-analyte test of practical clinical sera. This technique provides a new strategy for low cost, automated, and simultaneous multiplex immunoassay.

Encoded Silica Colloidal Crystal Beads as Supports for Potential Multiplex Immunoassay

We developed a new kind of suspension array for multiplexed immunoassays using silica colloidal crystal beads (SCCBs) as coding carriers. The monodisperse and size-controlled SCCBs were fabricated by a microfluidic device. Calcination was employed to improve the mechanical stability and lower the fluorescent background of the SCCBs. Immobilization of protein molecules on the surface of the SCCBs through chemical bonds was studied, and the modification condition was optimized to increase the detection sensitivity. Results indicated that the SCCBs as supports were more sensitive (0.92 ng/mL IgG) than the glass beads (27 ng/mL IgG) and the planar carriers (140 ng/mL IgG). A multiplex immunoassay showed the flexibility and feasibility of SCCBs array in clinical applications.