Molecularly Imprinted Polymer Sensor for Drug Residues

Reference#: P01409

Narcotics traffic throughout the world is a serious problem. Even though current interdiction methods has improved, it is certain that only a small percentage of drugs entering the United States are confiscated. One reason for the low rate of drug interdiction is the lack of adequate instrumentation available to field agents. Mass spectrometers and gas chromatographs are not portable and must be operated by well-trained technicians. Other methods, such as optical sensors and surface acoustic wave (SAW) devices have other limitations, primarily in the areas of sensitivity, specificity and/or the period of time required for testing. Therefore, instrumentation is needed that is readily portable, operable with a minimum of training, capable of detecting narcotics at extremely low concentration, minimally affected by interfering substances, rugged, and completely user friendly.

The Johns Hopkins Applied Physics Lab has developed molecularly imprinted polymers (MIP), a class of synthetic polymers that may be tailored to selectively detect a particular substance. The molecular imprinting technique involves a polymer, which has been synthesized in the presence of a target molecule, being used to separate a target molecule from other species. The polymers are constructed with ligands to contain cavities which closely match the shapes of various analyte molecules. The analyte molecules are incorporated into a pre-polymeric mixture and allowed to form bonds with the pre-polymer. The mixture is then polymerized with the analyte molecules in place. Once the polymer has formed, the analyte molecules are removed, leaving behind cavities with the analyte molecule's shape. In this way, a particular molecule can be identified since the shape of the cavity is specific to the molecule modeled. This method of identifying a particular molecule is attractive because of the simplicity of the preparation of the polymer and the simplicity and specificity of the identification of a target molecule.

This APL invention combines techniques of molecularly imprinting and sensitizing lanthanide luminescence to provide multiple criteria for selectivity for an analyte constituting a narcotic and virtually eliminating the possibility of false positive readings. This invention can detect the presence of narcotic vapors within a region or in a liquid in the parts per billion (ppb) or parts per quadrillion (ppq) levels, which is faster than similar sensors and that is free of false positives. The object of the present invention is to provide an optical based, or SAW based sensor device combined with luminescent materials containing lanthanide-complexes having a relatively long-lived luminescence or phosphorescence. For example, the MIP may be bound to a suitable substrate on a badge such that when a person or animal wearing the badge enters a zone or environment containing narcotic vapors, the narcotic vapors binds to the lanthanide-complex in the MIP thereby causing the lanthanide-complex to luminesce. Similarly, a MIP could be bound to a substrate and exposed to a liquid, e.g. blood thereby causing the lanthanide-complex to luminesce.

Dr. G. R. Jacobovitz
Phone: (443) 778-9899