ABSTRACT
Barcode particles have a demonstrated value for multiplexed bioassays in clinical diagnostics, drug discovery, and so on. Attempts to develop this technology are focusing on the generation of novel particles with a large number of identifications to increase the throughput of the assays. Here we report a new type of barcode particles with quantum dot (QD)-photonic crystal (PC) joint spectrum encoding. These barcode particles are simply prepared by in-situ polymerization of CdTe QDs-contained acrylamide pre-gel in the colloidal photonic crystal beads (PCBs). By encapsulating different wavelength-and-intensity QDs into the PCBs with various-reflection spectra, thousands of available barcode particles could be obtained. Moreover, by employing magnetic nanoparticles into the PCBs, the achieved barcode particles could be conferred a function of controllable movement under magnetic field. This feature could significantly increase the sensitivity and simplify the processing of the bioassays.
Subject(s)
Biological Assay/instrumentation , Coated Materials, Biocompatible/chemical synthesis , Nanotechnology/instrumentation , Oligonucleotide Array Sequence Analysis/instrumentation , Quantum Dots , Equipment Design , Equipment Failure Analysis , Light , MicrospheresABSTRACT
A technique for multiplex detection of organophosphorus pesticides and carbamate pesticides has been developed using a suspension array based on silica-hydrogel hybrid microbeads (SHHMs). The main advantage of SHHMs, which consist of both silica and hydrogel materials, is that they not only could be distinguished by their characteristic reflection peak originating from the stop-band of the photonic crystal but also have low non-specific adsorption of proteins. Using fluorescent immunoassay, the LODs for fenitrothion, chlorpyrifos-methyl, fenthion, carbaryl and metolcarb were measured to be 0.02ng/mL, 0.012ng/mL, 0.04ng/mL, 0.05ng/mL and 0.1ng/mL, respectively, all of which are much lower than the maximum residue limits, as reported in the European Union pesticides database. All the determination coefficients for these five pesticides were greater than 0.99, demonstrating excellent correlations. The suspension array was specific and had no significant cross-reactivity with other chemicals. The results for the detection of pesticide residues collected from agricultural samples using this method agree well with those from liquid chromatography-tandem mass spectrometry. Our results showed that this simple method is suitable for simultaneous detection of these five pesticides residues in fruits and vegetables.
Subject(s)
Carbamates/analysis , Hydrogels/chemistry , Organophosphorus Compounds/analysis , Pesticides/analysis , Silicon Dioxide/chemistry , Carbamates/chemistry , Fruit/chemistry , Microspheres , Organophosphorus Compounds/chemistry , Pesticides/chemistry , Vegetables/chemistryABSTRACT
Janus particles with features of an anisotropic photonic band gap (PBG) structure and magnetic property have been achieved by phase separation and self-assembly of nanoparticles in microfluidic droplets. The resultant particles enable optical encoding and magnetically controllable motion, making them excellent functional encoded particles in biomedical applications.
ABSTRACT
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.
Subject(s)
Chlorpyrifos/analogs & derivatives , Fenitrothion/analysis , Microarray Analysis , Pesticide Residues/analysis , Chlorpyrifos/analysis , Immunoassay , Limit of Detection , Photons , Silicon Dioxide/chemistry , Spectrometry, Fluorescence , Suspensions/chemistryABSTRACT
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.
