Identification of Viruses Using Microfluidic Protein Profiling and Bayesian Classification

Four-step approach to efficiently develop capillary gel electrophoresis methods for viral vaccine protein analysis

Vaccines against infectious diseases are urgently needed. Therefore, modern analytical method development should be as efficient as possible to speed up vaccine development. The objectives of the study were to identify critical method parameters (CMPs) and to establish a set of steps to efficiently develop and validate a CE‐SDS method for vaccine protein analysis based on a commercially available gel buffer. The CMPs were obtained from reviewing the literature and testing the effects of gel buffer dilution. A four‐step approach, including two multivariate DoE (design of experiments) steps, was proposed, based on CMPs and was verified by CE‐SDS method development for: (i) the determination of influenza group 1 mini‐hemagglutinin glycoprotein; and (ii) the determination of polio virus particle proteins from an inactivated polio vaccine (IPV). The CMPs for sample preparation were incubation temperature(s) and time(s), pH, and reagent(s) concentration(s), and the detection wavelength. The effects of gel buffer dilution revealed the CMPs for CE‐SDS separation to be the effective length, the gel buffer concentration, and the capillary temperature. The four‐step approach based on the CMPs was efficient for the development of the two CE methods. A four‐step approach to efficiently develop capillary gel electrophoresis methods for viral vaccine protein analysis was successfully established.

Application of CGE to virus identification

Protein profiling is an increasingly valuable tool for the characterization of protein populations and has been used to identify microorganisms, most often using two-dimensional gel electrophoresis followed by mass spectrometry. We present a rapid method for the identification of viruses using microfluidic chip gel electrophoresis (CGE) of high-copy number proteins to generate unique protein profiles. Viral proteins are solubilized, fluorescently labeled and then analyzed using the μChemLab™ CGE system (∼10 min overall). A Bayesian classification approach is used to classify the reproducible and visually distinct protein profiles of MS2 bacteriophage, Epstein-Barr, Respiratory Syncytial, and Vaccinia viruses as well as discriminate between closely related T2 and T4 bacteriophage.

Exploring the feasibility of bioaerosol analysis as a novel fingerprinting technique

The purpose of this review is to investigate the feasibility of bioaerosol fingerprinting based on current understanding of cellular debris (with emphasis on human-emitted particulates) in aerosols and arguments regarding sampling, sensitivity, separations, and detection schemes. Target aerosol particles include cellular material and proteins emitted by humans, animals, and plants and can be regarded as information-rich packets that carry biochemical information specific to the living organisms present where the sample is collected. In this work we discuss sampling and analysis techniques that can be integrated with molecular (e.g. protein)-detection procedures to properly assess the aerosolized cellular material of interest. Developing a detailed understanding of bioaerosol molecular profiles in different environments suggests exciting possibilities of bioaerosol analysis with applications ranging from military defense to medical diagnosis and wildlife identification.

Development of an integrated microfluidic instrument for unattended water-monitoring applications

Field-deployable detection technologies in the nation's water supplies have become a high priority in recent years. The unattended water sensor is presented which employs microfluidic chip-based gel electrophoresis for monitoring proteinaceous analytes in a small integrated sensor platform. The instrument collects samples directly from a domestic water flow. The sample is then processed in an automated microfluidic module using in-house designed fittings, microfluidic pumps and valves prior to analysis via Sandia's microChemLab module, which couples chip-based electrophoresis separations with sensitive LIF detection. The system is controlled using LabVIEW software to analyze water samples about every 12 min. The sample preparation, detection and data analysis has all been fully automated. Pressure transducers and a positive control verify correct operation of the system, remotely. A two-color LIF detector with internal standards allows corrections to migration time to account for ambient temperature changes. The initial unattended water sensor prototype is configured to detect protein biotoxins such as ricin as a first step toward a total bioanalysis capability based on protein profiling. The system has undergone significant testing at two water utilities. The design and optimization of the sample preparation train is presented with results from both laboratory and field testing.

An ultra-high temperature flow-through capillary device for bacterial spore lysis

Rapid and specific characterization of bacterial endospores is dependent on the ability to rupture the cell wall to enable analysis of the intracellular components. In particular, bacterial spores from the bacillus genus are inherently robust and very difficult to lyze or solubilize. Standard protocols for spore inactivation include chemical treatment, sonication, pressure, and thermal lysis. Although these protocols are effective for the inactivation of these agents, they are less well suited for sample preparation for analysis using proteomic and genomic approaches. To overcome this difficulty, we have designed a simple capillary device to perform thermal lysis of bacterial spores. Using this device, we were able to super heat (195 degrees C) an ethylene glycol lysis buffer to perform rapid flow-through rupture and solubilization of bacterial endospores. We demonstrated that the lysates from this preparation method are compatible with CGE as well as DNA amplification analysis. We further demonstrated the flow-through lysing device could be directly coupled to a miniaturized electrophoresis instrument for integrated sample preparation and analysis. In this arrangement, we were enabled to perform sample lysis, fluorescent dye labeling, and protein electrophoresis analysis of bacterial spores in less than 10 min. The described sample preparation device is rapid, simple, inexpensive, and easily integratable with various microfluidic devices.