Application Of Bioassay Research Articles

Effect of halogenated fluorescent compounds on bioluminescent reactions

The paper investigates an application of luminescent bioassays to monitor the toxicity of organic halides. Effects of xanthene dyes (fluorescein, eosin Y, and erythrosin B), used as model compounds, on bioluminescent reactions of firefly Luciola mingrelica, marine bacteria Photobacterium leiognathi, and hydroid polyp Obelia longissima were studied. Dependence of bioluminescence quenching constants on the atomic weight of halogen substituents in dye molecules was demonstrated. Bacterial bioluminescence was shown to be most sensitive to heavy halogen atoms involved in molecular structure; hence, it is suitable for construction of sensors to monitor toxicity of halogenated compounds. Mechanisms of bioluminescence quenching--energy transfer processes, collisional interactions, and enzyme-dye binding--were considered. Changes of bioluminescence (BL) spectra in the presence of the dyes were analyzed. Interactions of the dyes with enzymes were studied using fluorescence characteristics of the dyes in steady-state and time-resolved experiments. The dependences of fluorescence anisotropy of enzyme-bound dyes, the average fluorescence lifetime, and the number of exponential components in fluorescence decay on the atomic weight of halogen substituents were demonstrated. The results are discussed in terms of "dark effect of heavy halogen atom" in the process of enzyme-dye binding; hydrophobic interactions were assumed to be responsible for the effect.

Soil bioassay: Problems and approaches

The methodological and organizational problems of the practical application of soil bioassay to monitor the state of soils for environmental, agricultural, and sanitary-epidemiological purposes are analyzed. To improve the efficiency of the integral valuation of soil toxicity, soil bioassay should be performed with a set of organisms (sensors) representing the major trophic levels of the ecosystems, i.e., producers, consumers, and decomposers.

Application of a Fluorescence-Based Continuous-Flow Bioassay to Screen for Diversity of Cytochrome P450 BM3 Mutant Libraries

A fluorescence-based continuous-flow enzyme affinity detection (EAD) setup was used to screen cytochrome P450 BM3 mutants on-line for diversity. The flow-injection screening assay is based on the BM3-mediated O-dealkylation of alkoxyresorufins forming the highly fluorescent product resorufin, and can be used in different configurations, namely injection of ligands, enzymes and substrates. Screening conditions were optimized and the activity of a library of 32 BM3 mutants towards the recently synthesized new probe substrate allyloxyresorufin was measured in flow-injection analysis (FIA) mode and it was shown that large activity differences between the mutants existed. Next, six BM3 mutants containing mutations at different positions in the active site were selected for which on-line enzyme kinetics were determined. Subsequently, for these six BM3 mutants affinity towards a set of 30 xenobiotics was determined in FIA EAD mode. It was demonstrated that significant differences existed for the affinity profiles of the mutants tested and that these differences correlated to alterations in the BM3 mutant-generated metabolic profiles of the drug buspirone. In conclusion, the developed FIA EAD approach is suitable to screen for diversity within BM3 mutants and this alternative screening technology offers new perspectives for rapid and sensitive screening of compound libraries towards BM3 mutants.

The sea urchin, a versatile model for eco-toxicity studies and ecological experimental research

Echinoderm early developmental stages represent a good tool for toxicity testing in different fields, ranging from environment to food contamination, and in full respect of the 3Rs objectives (Reduction, Refinement, Replacement of animal experiments), that will lead to the reduction of vertebrate use for toxicity testing. Further, sea urchins are key species in a wide range of marine habitats, as they are able to structure algal community. Experiments and observations aiming at the characterization of anthropogenic or climate changes effects on their settlement, population structure, feeding behaviour and reproductive condition, may be useful to describe future scenarios regarding the whole marine community. The present paper represents a short review of the possible applications of eco-toxicity bioassays using Paracentrotus lividus gametes and embryos. Further, examples of ecological researches, involving sea urchins, aiming at the definition of future scenarios will be preserved.

Development of sediment quality guidelines for freshwater ecosystems

The development of Sediment Quality Guidelines (SQGs) is one of the remaining challenges for a better protection of aquatic biodiversity and in particular sediment dwelling organisms. So far, sediment quality assessment in Flanders was based on a comparison of chemical concentrations to the geometric mean of the concentrations at 12 reference sites. The study described in this paper addressed the need for more science-based guidelines. The developed guidelines are already incorporated into Flemish legislation. Based on a large sediment monitoring database, containing physico-chemical properties, concentrations of chemicals, macrobenthic community assemblages and ecotoxicological data, Sediment Effect Concentrations (SECs) were calculated as basis for the SQGs. The derived SECs were based on ecological effects, namely Lowest and Severe Effect Levels (LEL/SEL), as well as ecotoxicological endpoints, namely Threshold and Probable Effect Levels (TEL/PEL). The average values of the ecological and ecotoxicological SECs were used to distinguish five sediment quality classes. The ecological values were in general less stringent than the ecotoxicological values. However, the Lowest Effect Levels (95% of the benthic taxa can be present under this level) and Threshold Effect Levels (no toxic effect is expected under this level) did not differ significantly. Probable Effect Levels (concentrations above this level will certainly result in toxic effects) were generally lower than the Severe Effect Levels (above this level only 5% or less of the taxa are present). The SECs calculated in this study enabled us to correctly identify 87.9% of the sediments as toxic. The development of SQGs based on a combination of the LEL/SEL and TEL/PEL methods enabled us to underpin these SQGs based on field observations and will improve the assessment of sediment quality based on chemical parameters. Although sediments typically contain complex mixtures of contaminants, only a limited number of these contaminants will be measured. Additional application of bioassays for the overall sediment quality assessment is therefore recommended. This study describes the development of SQGs in Flanders, which are based on ecological and ecotoxicological data derived from a TRIAD monitoring network. The combination of the LEL and PEL resulted in SQGs that were recently incorporated in Flemish legislation and for which the respective pore water concentrations were in the same order of magnitude as the Annual Average Environmental Quality Standards values for Water Framework Directive priority pollutants.

Characterization of dioxin-like contamination in soil and sediments from the “hot spot” area of petrochemical plant in Pancevo (Serbia)

Combinatorial bio/chemical approach was applied to investigate dioxin-like contamination of soil and sediment at the petrochemical and organochlorine plant in Pancevo, Serbia, after the destruction of manufacturing facilities that occurred in the spring of 1999 and subsequent remediation actions. Soil samples were analyzed for indicator polychlorinated biphenyls (PCBs) by gas chromatography/electron capture detection (GC/ECD). Prioritized soil sample and sediment samples from the waste water channel were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). Microethoxyresorufin o-deethylase (Micro-EROD) and H4IIE-luciferase bioassays were used for monitoring of dioxin-like compounds (DLC) and for better characterization of dioxin-like activity of soil samples. Bioanalytical results indicated high dioxin-like activity in one localized soil sample, while the chemical analysis confirmed the presence of large quantities of DLC: 3.0 × 10(5)ng/g d.w. of seven-key PCBs, 8.2ng/g d.w. of PCDD/Fs, and 3.0 × 10(5)ng/g d.w. of planar and mono-ortho PCBs. In the sediment, contaminant concentrations were in the range 2-8ng/g d.w. of PCDD/Fs and 9-20ng/g d.w. of PCBs. This study demonstrates the utility of combined application of bioassays and instrumental analysis, especially for developing and transition country which do not have capacity of the expensive instrumental analysis. The results indicate the high contamination of soil in the area of petrochemical plant, and PCDD/Fs contamination of the sediment from the waste water channel originating from the ethylene dichloride production.

Magnetic Electrochemiluminescent Fe3O4/CdSe–CdS Nanoparticle/Polyelectrolyte Nanocomposite for Highly Efficient Immunosensing of a Cancer Biomarker

Magnetic electrochemiluminescent Fe(3)O(4)/CdSe-CdS nanoparticle/polyelectrolyte nanostructures have been synthesized and used to fabricate an electrochemiluminescence (ECL) immunosensor for the detection of carcinoembryonic antigen (CEA). CEA is a protein used as a biomarker for several cancers; particularly, to monitor response to treatment in colon and rectal cancer patients. The nanocomposites can be easily separated and firmly attached to an electrode owing to their excellent magnetic properties. This represents a promising advantage for bioassay applications. More importantly, the nanostructures exhibit intense and stable ECL emissions in neutral solution, which makes them ideal for ECL immunosensing. The 3-aminopropyltriethoxysilane (APS) polyelectrolyte shell on the nanostructure surface not only enhances the intensity and stability of the ECL signal, but also acts as a crosslinker for immunosensor fabrication. A CEA antibody immobilized onto a nanocomposite/APS/electrode with gold nanoparticles comprises the ECL immunosensor. The principle of ECL detection for CEA is based on a change in steric hindrance after immunoreaction, which leads to a decrease in ECL intensity. A wide detection range (0.064 pg ml(-1)-10 ng ml(-1)) and low detection limit (0.032 pg ml(-1)) are achieved. The immunosensor is highly sensitive and selective, and exhibits excellent stability and good reproducibility. It thus has great potential for clinical protein detection. In particular, this approach uses a novel class of bifunctional nanocomposites that display both intense ECL and excellent magnetism, which renders them suitable for a large range of bioassay applications.

Novel Multiparametric Approach to Elucidate the Surface Amine-Silanization Reaction Profile on Fluorescent Silica Nanoparticles

This Article addresses the important issue of the characterization of surface functional groups for optical bioassay applications. We use a model system consisting of spherical dye-doped silica nanoparticles (NPs) that have been functionalized with amine groups whereby the encapsulated cyanine-based near-infrared dye fluorescence acts as a probe of the NP surface environment. This facilitates the identification of the optimum deposition parameters for the formation of a stable ordered amine monolayer and also elucidates the functionalization profile of the amine-silanization process. Specifically, we use a novel approach where the techniques of fluorescence correlation spectroscopy (FCS) and fluorescence lifetime measurement (FL) are used in conjunction with the more conventional analytical techniques of zeta potential measurement and Fourier transfer infrared spectroscopy (FTIR). The dynamics of the ordering of the amine layer in different stages of the reaction have been characterized by FTIR, FL, and FCS. The results indicate an optimum reaction time for the formation of a stable amine layer, which is optimized for further biomolecular conjugation, whereas extended reaction times lead to a disordered cross-linked layer. The results have been validated using an immunoglobulin (IgG) plate-based direct binding assay where the maximum number of IgG-conjugated aminated NPs were captured by immobilized anti-IgG antibodies for the NP sample corresponding to the optimized amine-silanization condition. Importantly, these results point to the potential of FCS and FL as useful analytical tools in diverse fields such as characterization of surface functionalization.

Au@Pt nanostructures as oxidase and peroxidase mimetics for use in immunoassays

In this paper, we demonstrated that Au nanorods coated with a shell composed of Pt nanodots (Au@Pt nanostructures) exhibited intrinsic oxidase-like, peroxidase-like and catalase-like activity, catalyzing oxygen and hydrogen peroxide reduction and the dismutation decomposition of hydrogen peroxide to produce oxygen. Based on these findings, we established an Au@Pt nanostructures based enzyme linked immunosorbent assay (ELISA) for the detection of mouse interleukin 2 (IL-2). In comparison with natural enzymes, Au@Pt nanostructures have advantages of low cost, easy preparation, better stability, and tunable catalytic activity (compared with HRP), which make them a promising enzyme mimetic candidate and may find potential applications in biocatalysis, bioassays, and nano-biomedicine such as reactive oxygen species (ROS)-related fields (anti-aging and therapeutics for neurodegenerative diseases and cancers).

Bio-logic analysis of injury biomarker patterns in human serum samples

Digital biosensor systems analyzing biomarkers characteristic of liver injury (LI), soft tissue injury (STI) and abdominal trauma (ABT) were developed and optimized for their performance in serum solutions spiked with injury biomarkers in order to mimic real medical samples. The systems produced ‘Alert’-type optical output signals in the form of “YES-NO” separated by a threshold value. The new approach aims at the reliable detection of injury biomarkers for making autonomous decisions towards timely therapeutic interventions, particularly in conditions when a hospital treatment is not possible. The enzyme-catalyzed reactions performing Boolean AND/ NAND logic operations in the presence of different combinations of the injury biomarkers allowed high-fidelity biosensing. Robustness of the systems was confirmed by their operation in serum solutions, representing the first example of chemically performed logic analysis of biological fluids and a step closer towards practical biomedical applications of enzyme-logic bioassays.

Application of bioassay in quality control of Chinese materia medica-taking Radix Isatidis as an example

Bioassay, which construct the characteristics consistents with Chinese medical science, is the core mode and methods for the quality control of Chinese materia medica. Taking the bioassay of Radix Isatidis as an example, the contribution, status and application of bioassay in the quality control of Chinese materia medica were introduced in this article, and two key issue (the selection of reference and measurement methods) in the process of establishing bioassay were also explained. This article expects to provide a reference for the development and improvement of the bioassay of Chinese materia medica in a practical manipulation level.

Application of bioassays in toxicological hazard, risk and impact assessments of dredged sediments

Given the potential environmental consequences of dumped dredged harbour sediments it is vital to establish the potential risks from exposure before disposal at sea. Currently, European legislation for disposal of contaminated sediments at sea is based on chemical analysis of a limited number of well-known contaminants for which maximum acceptable concentrations, action levels (ALs), have been set. The present paper addresses the issue of the applicability of in vitro and in vivo bioassays for hazard, risk and local impact assessment of dredged polluted sediments to be disposed of at sea. It discusses how and to what extent selected bioassays can fill in the gaps left open by chemical analysis and the way in which the bioassays may contribute to the present licensing system for disposal. Three different purposes for application were distinguished: the most basic application (A) is a rapid determination of the hazard (potential toxicity) of dredged sediments which is then compared to ALs in a licensing system. As with chemical analysis on whole sediment extracts, the bioavailability of the chemicals is not taken into account. As in vitro assays with sediment extracts are not sensitive to matrix effects, a selection of specific in vitro bioassays can be suitable fast and standardized additions for the licensing system. When the outcome of (A) does not convincingly demonstrate whether the sediment is clean enough or too polluted, further bioanalysis can help the decision making process (B). More aspects of the mostly unknown complex chemical mixtures are taken into account, including the bioavailability and chronic toxicity focusing on ecologically relevant endpoints. The ecotoxicological pressure imposed by the dredged sediments can be quantified as the potentially affected fraction (PAF) based on chemical or biological analysis of levels of contaminants in sediment or biota. To validate the predicted risk, the actual impact of dumped harbour sediments on local ecosystems (C) can be determined using a dedicated set of in vitro and in vivo bioassays as well as bio-indicators selected based on the information obtained from (A) and (B) and on the characteristics of the local ecosystem. Conversely, the local sediment impact assessment (C) can direct fine-tuning of the selection of chemical and bioassay analyses and for setting safe levels in the licensing system. It is concluded that in vitro and in vivo bioassays and biological indicators are useful tools in the process of hazard, ecotoxicological risk and impact assessment of dredged harbour sediments, provided they are consciously chosen and quality criteria for assay performance are defined.

Application of stimulating agents on the immobilized bioluminescence strain Pseudomonas putida mt-2 KG1206, preserved by deep-freezing, for the convenient biomonitoring

Abstract This study was conducted to develop methods for the application of an immobilized bioluminescence strain (KG1206), preserved by deep-freezing (DF), for the monitoring of contaminated environments. The immobilized cells, preserved by DF, required approximately 2 hr for reconstitution of their activity. A large reduction in bioluminescence was observed due to the DF process; 0.07-0.58 times that of the non deep-frozen (NDF) immobilized strain. The decreased bioluminescence activity induced by the DF process was enhanced by the stimulants, sodium lactate (SL) and KNO 3. However, regardless of the inducer chemical tested, the immobilized strain modified with KNO 3 consistently produced greater bioluminescence than that treated with SL, in the range of 3.0-10.7 (avg. 6.7 ± 3.69) and 1.2-4.2 (avg. 2.4 ± 1.47) times that of control, respectively. All KNO 3 treatments of contaminated groundwater samples also resulted in an increase in bioluminescence activity, but the rate of stimulation varied for each sample. Also, no strong linear correlation was observed between the bioluminescence and the total concentration of an inducer, which may related to the complex characteristics of the environmental samples. Overall, the results demonstrated the ability of immobilized genetically engineered bacteria, preserved by DF, to measure a specific group of environmental contaminants using a stimulating agent (KNO 3), suggesting the potential for its preliminary application in a field-ready bioassay.

The discovery of endothelin: The power of bioassay and the role of serendipity in the discovery of endothelium-derived vasocative substances

Significant discoveries in biology and medicine are rare. The progress in these fields is predominantly incremental, but sometimes new observations revolutionize the field by opening new directions in research for decades to come. Two cornerstone observations in the late 1970s and early 1980s are examples of such “revolutionary” events. The first, by Furchgott and Zawadzki, was the discovery of the “obligatory role of the endothelium in vasorelaxation by acetylcholine”. The other, by Hickey and colleagues, was the first description and characterization of a vasoconstrictor polypeptide produced by endothelial cells in culture. Both of these observations were achieved by the application of bioassay and serendipity played an important role in each of them. They both represent starting points for rapid growth in research activity world-wide leading to the identification of EDRF as nitric oxide, and the polypeptide EDCF as endothelin a few years later. These early observations also raised interest and initiated intensive R&D activity in the pharma industry culminating in the regulatory approval and marketing of novel medicines treating human diseases. This review describes the events leading to the discovery and early characterization of the peptidergic endothelium-derived constrictor factor, and its purification, sequencing and naming it endothelin.

Ultrafast and sensitive bioassay using split ring resonator structures and microwave heating

In this paper, we have reported that split ring resonators (SRRs) structures can be used for bioassay applications in order to further improve the assay time and sensitivity. The proof-of-principle demonstration of the ultrafast bioassays was accomplished by using a model biotin-avidin bioassay. While the identical room temperature bioassay (without microwave heating) took 70 min to complete, the identical bioassay took less than 2 min to complete by using SRR structures (with microwave heating). A lower detection limit of 0.01 nM for biotinylated-bovine serum albumin (100-fold lower than the room temperature bioassay) was observed by using SRR structures.

Integrated control-path design and error recovery in the synthesis of digital microfluidic lab-on-chip

Recent advances in digital microfluidics have led to tremendous interest in miniaturized lab-on-chip devices for biochemical analysis. Synthesis tools have also emerged for the automated design of lab-on-chip from the specifications of laboratory protocols. However, none of these tools consider control flow or address the problem of recovering from fluidic errors that can occur during on-chip bioassay execution. We present a synthesis method that incorporates control paths and an error-recovery mechanism in the design of a digital microfluidic lab-on-chip. Based on error-propagation estimates, we determine the best locations for fluidic checkpoints during biochip synthesis. A microcontroller coordinates the implementation of the control-flow-based bioassay by intercepting the synthesis results that are mapped to the software programs. Real-life bioassay applications are used as case studies to evaluate the proposed design method. For a representative protein assay, compared to a baseline chip design, the biochip with a control path can reduce the completion time by 30% when errors occur during the implementation of the bioassay.

Development and Validation of a Quantitative, High-Throughput, Fluorescent-Based Bioassay to Detect Schistosoma Viability

BackgroundSchistosomiasis, caused by infection with the blood fluke Schistosoma, is responsible for greater than 200,000 human deaths per annum. Objective high-throughput screens for detecting novel anti-schistosomal targets will drive ‘genome to drug’ lead translational science at an unprecedented rate. Current methods for detecting schistosome viability rely on qualitative microscopic criteria, which require an understanding of parasite morphology, and most importantly, must be subjectively interpreted. These limitations, in the current state of the art, have significantly impeded progress into whole schistosome screening for next generation chemotherapies.Methodology/Principal FindingsWe present here a microtiter plate-based method for reproducibly detecting schistosomula viability that takes advantage of the differential uptake of fluorophores (propidium iodide and fluorescein diacetate) by living organisms. We validate this high-throughput system in detecting schistosomula viability using auranofin (a known inhibitor of thioredoxin glutathione reductase), praziquantel and a range of small compounds with previously-described (gambogic acid, sodium salinomycin, ethinyl estradiol, fluoxetidine hydrochloride, miconazole nitrate, chlorpromazine hydrochloride, amphotericin b, niclosamide) or suggested (bepridil, ciclopirox, rescinnamine, flucytosine, vinblastine and carbidopa) anti-schistosomal activities. This developed method is sensitive (200 schistosomula/well can be assayed), relevant to industrial (384-well microtiter plate compatibility) and academic (96-well microtiter plate compatibility) settings, translatable to functional genomics screens and drug assays, does not require a priori knowledge of schistosome biology and is quantitative.Conclusions/SignificanceThe wide-scale application of this fluorescence-based bioassay will greatly accelerate the objective identification of novel therapeutic lead targets/compounds to combat schistosomiasis. Adapting this bioassay for use with other parasitic worm species further offers an opportunity for great strides to be made against additional neglected tropical diseases of biomedical and veterinary importance.

Electrochemical immunosensor of tumor necrosis factor α based on alkaline phosphatase functionalized nanospheres

A novel immunosensor for sensitive detection of tumor necrosis factor α was reported. First of all, gold nanoparticles were uniformly assembled on the surface of poly (styrene-acrylic acid) nanospheres, which was used as the matrix to conjugate alkaline phosphatase (ALP). And then, the obtained composite was used as multi-enzyme functionalized label for immunoassay. Biocompatible polyaniline doped with poly (acrylic acid) was electro-polymerized at the glass carbon electrode to construct the matrix for the immobilization of antibody TNF-α. After the sandwich immunoreaction, the labeled ALP was used to hydrolyze α-naphthyl phosphate to produce the electroactive α-naphthol, which could be amperometrically detected. The results showed that the electrochemical signals were proportional to the logarithm of the antigen concentration in the range of 0.02–200.00 ng/mL with the detection limit of 0.01 ng/mL. The developed immunoassay showed high sensitivity, acceptable stability and reproducibility, which might have potentially broad applications in protein diagnostics and bioassay.

Development of a Visible-Light-Sensitized Europium Complex for Time-Resolved Fluorometric Application

The time-resolved luminescence bioassay technique using luminescent lanthanide complexes as labels is a highly sensitive and widely used bioassay method for clinical diagnostics and biotechnology. A major drawback of the current technique is that the luminescent lanthanide labels require UV excitation (typically less than 360 nm), which can damage living biological systems and is holding back further development of time-resolved luminescence instruments. Herein we describe two approaches for preparing a visible-light-sensitized Eu(3+) complex in aqueous media for time-resolved fluorometric applications: a dissociation enhancement aqueous solution that can be excited by visible light for ethylenediaminetetraacetate (EDTA)-Eu(3+) detection and a visible-light-sensitized water-soluble Eu(3+) complex conjugated bovine serum albumin (BSA) for biolabeling and time-resolved luminescence bioimaging. In the first approach, a weakly acidic aqueous solution consisting of 4,4'-bis(1'',1'',1'',2'',2'',3'',3''-heptafluoro-4'',6''-hexanedion-6''-yl)-o-terphenyl (BHHT), 2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine (DPBT), and Triton X-100 was prepared. This solution shows a strong luminescence enhancement effect for EDTA-Eu(3+) with a wide excitation wavelength range from UV to visible light (a maximum at 387 nm) and a long luminescence lifetime (520 micros), to provide a novel dissociation enhancement solution for time-resolved luminescence detection of EDTA-Eu(3+). In the second approach, a ternary Eu(3+) complex, 4,4'-bis(1'',1'',1'',2'',2'',3'',3''-heptafluoro-4'',6''-hexanedion-6''-yl)-chlorosulfo-o-terphenyl (BHHCT)-Eu(3+)-DPBT, was covalently bound to BSA to form a water-soluble BSA-BHHCT-Eu(3+)-DPBT conjugate. This biocompatible conjugate is of the visible-light excitable feature in aqueous media with a wide excitation wavelength range from UV to visible light (a maximum at 387 nm), a long luminescence lifetime (460 micros), and a higher quantum yield (27%). The conjugate was successfully used for streptavidin (SA) labeling and time-resolved luminescence imaging detection of three environmental pathogens, Giardia lamblia , Cryptosporidium muris , and Cryptosporidium parvum , in water samples. Our strategy gives a general idea for designing a visible-light-sensitized Eu(3+) complex for time-resolved luminescence bioassay applications.

High-Resolution Spectral Analysis of Individual SERS-Active Nanoparticles in Flow

Nanoparticle spectroscopic tags based on surface enhanced Raman scattering (SERS) are playing an increasingly important role in bioassay and imaging applications. The ability to rapidly characterize large populations of such tags spectroscopically in a high-throughput flow-based platform will open new areas for their application and provide new tools for advancing their development. We demonstrate here a high-resolution spectral flow cytometer capable of acquiring Raman spectra of individual SERS-tags at flow rates of hundreds of particles per second, while maintaining the spectral resolution required to make full use of the detailed information encoded in the Raman signature for advanced multiplexing needs. The approach allows multiple optical parameters to be acquired simultaneously over thousands of individual nanoparticle tags. Characteristics such as tag size, brightness, and spectral uniformity are correlated on a per-particle basis. The tags evaluated here display highly uniform spectral signatures, but with greater variability in brightness. Subpopulations in the SERS response, not apparent in ensemble measurements, are also shown to exist. Relating tag variability to synthesis parameters makes flow-based spectral characterization a powerful tool for advancing particle development through its ability to provide rapid feedback on strategies aimed at constraining desired tag properties. Evidence for single-tag signal saturation at high excitation power densities is also shown, suggesting a role for high-throughput investigation of fundamental properties of the SERS tags as well.