Explosive materials are increasingly being exploited by criminal organisations,with harmful, devastating and destructive effects on targeted societies; highlighting the demand for sensitive, reliable and quick explosive detection methods that can be used in a range of environments. Immunoassays are one type of test that can provide these qualities. Immunoassays use antibodies to detect a molecule of interest (analyte). A common type of user-friendly immunoassay that has been employed for a wide-range of applications is the lateral flow immunoassay (LFIA). A LFIA simplifies the immunoassay procedure, applying the principle (discussed in detail later) to perform along a single axis by utilising a porous membrane. This type of test is quick, sensitive and relatively easy to use, which means it is accessible by non-specialised personnel. This research uses a competitive immunoassay format, which arises from competitive binding between a free form and a bound form of the analyte. Successful detection of explosive material: 2,4,6-trinitrotoluene (TNT) has been demonstrated via a competitive immunoassay technique. Through optimisation of reagents and conditions, the limit of detection is 0.03 μg ml-1 (300 pg per fingerprint deposit) on a plate assay format. Initial steps have been taken to apply this mechanism to the LFIA format to produce a test. However, further research is required before a functioning device is ready for commercial value.
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