Combinational Biosensor

#This invention relates to detection of bioagents (and/or nucleic acids), and, more particularly, to a method for identifying the presence of bioagents and/or nucleic acids of specific interest in a specimen in the shortest possible time, with a minimum of necessary equipment and with known tests.

#Health authorities are ever alert to the outbreak of a contagious disease that, if not checked early, could grow to epidemic proportion amongst the general population. To that purpose, the health authorities are charged with monitoring the environment for the incidence of unusual illnesses, symptomatic of a disease, obtaining and analyzing samples to identify the biological agent causing the disease, and, once identified, publish protective measures that must be taken to halt the spread of the disease. Typically, biological agents, such as viruses and bacteria, are part of nature, and outbreaks of disease occur naturally. However, biological terrorism, the deliberate release of a harmful virus or bacteria or other biological agent (hereafter, “bioagent”) amongst a general population, and bio-warfare, the deliberate release of a bioagent against military troops in battle, are also of concern.

#One known test procedure or process for detection of a specific bioagent that is applicable to a variety of fields, such as biotechnology, environmental protection and public health, is the enzyme linked immunoassay (hereafter referred to as “ELISA”). The ELISA process constitutes an identification process that uses molecular interactions to uniquely identify target substances. A basic definition of ELISA is a quantitative in vitro test for an antibody or antigen (e.g., a bioagent) in which the test material is adsorbed on a surface and exposed to a complex of an enzyme linked to an antibody specific for the substance being tested for with a positive result indicated by a treatment yielding a color in proportion to the amount of antigen or antibody in the test material. The basic ELISA procedure is described more specifically, for one, in a book entitled Methods in Molecular Biology Vol 42, John R. Crowther, Humana Press, 1995.

#FIGS. 1 and 2 are high level pictorial illustrations of an embodiment for identifying a bioagent from amongst nine different possible bioagents, respectively representing the primary and secondary procedures used to identify the bioagent.

#FIG. 3 illustrates the embodiment of FIGS. 1 and 2 in greater detail.

#The following description assumes a familiarity with the ELISA process described in the preceding background and, in greater detail in the '16714 PCT application and the '946 application. A starting point in an ELISA test is to coat receptor molecules on beads. Specifically the beads are coated with a receptor molecule (e.g., recognition molecule or, as variously termed “1° Ab”) that adsorbs a specific antigen (hereafter referred to as a bioagent). Likewise, the ELISA test requires a secondary antibody-enzyme conjugate, specific to the bioagent (e.g., 2° Ab-enz). The ELISA test for that specific bioagent determines both the presence of that bioagent in the solution, and, if present, the concentration of the bioagent. The purpose of the present invention is to identify the presence of a suspect bioagent from a plurality of predetermined candidates.

#FIGS. 1 and 2 are high level pictorial illustrations of an embodiment for identifying a bioagent from amongst nine different possible bioagents, respectively representing the primary and secondary procedures used to identify the bioagent. For convenience, the nomenclature used to denominate the elements in those figures is considered. In this description, the letter X1 represents a bead coating (e.g. the recognition molecule) that serves as a receptor for a specific bioagent (and may also be used to represent the secondary antibody-enzyme conjugate specific to the bioagent (e.g., 2° Ab-enz). The specific bioagent is given a corresponding designation AX1. As example, the bead coatings for three bioagents AX1, AX2 and AX3 are represented as X1, X2 and X3.

#To run an ELISA test for three bioagents using a conventional ELISA test procedure, it is necessary to have three separate recognition molecules for those bioagents, accomplished, for example, with a first vial with beads coated with receptor molecule X1, another vial of beads coated with receptor molecule X2 and a third vial coated with receptor molecule X3. It is also necessary in the ELISA process to have the three separate secondary antibody-enzyme conjugate (e.g., 2° Ab-enz) specific to the bioagent associated with AX1, AX2 and AX3. A given sample of the bioagent is divided into three parts and placed in the corresponding vial of coated beads. Each vial is tested in turn using the ELISA procedure to determine the existence of the corresponding agent in the sample and, if present, the concentration of each. The present invention and method employs that prior technique as a secondary identification procedure, illustrated in FIG. 2.