Noninvasive Detection of Cocaine and Heroin Use with Single Fingerprints: Determination of an Environmental Cutoff.

BACKGROUND: Recent publications have explored the possibility of using fingerprints to confirm drug use, but none has yet dealt with environmental contamination from fingertips. Here we explored the possibility of establishing an environmental cutoff for drug testing from a single fingerprint. METHODS: Fingerprint samples (n = 100) were collected from the hands of 50 nondrug users before and after handwashing to establish separate environmental cutoff values and testing protocols for cocaine, benzoylecgonine, heroin, and 6-monoacetylmorphine. The cutoff was challenged by testing the fingerprints of drug-free volunteers after shaking hands with drug users. Fingerprints from patients who testified to taking cocaine (n = 32) and heroin (n = 24) were also collected and analyzed. RESULTS: A different cutoff value needed to be applied, depending on whether the fingerprints were collected as presented or after handwashing. Applying these cutoffs gave a 0% false-positive rate from the drug-free volunteers. After application of the cutoff, the detection rate (compared to patient testimony) for washed hands of patients was 87.5% for cocaine use and 100% for heroin use. CONCLUSIONS: Fingerprints show enhanced levels of cocaine, heroin, and their respective metabolites in patients who testified to taking the substances, compared with the population of naïve drug users surveyed, and a cutoff (decision level) can be established. The cutoff is robust enough to account for small increases in analyte observed after secondary transfer.

Determination of protein binding affinities within hydrogel-based molecularly imprinted polymers (HydroMIPs).

Hydrogel-based molecularly imprinted polymers (HydroMIPs) were prepared for several proteins (haemoglobin, myoglobin and catalase) using a family of acrylamide-based monomers. Protein affinity towards the HydroMIPs was investigated under equilibrium conditions and over a range of concentrations using specific binding with Hill slope saturation profiles. We report HydroMIP binding affinities, in terms of equilibrium dissociation constants (Kd) within the micro-molar range (25 ± 4 µM, 44 ± 3 µM, 17 ± 2 µM for haemoglobin, myoglobin and catalase respectively within a polyacrylamide-based MIP). The extent of non-specific binding or cross-selectivity for non-target proteins has also been assessed. It is concluded that both selectivity and affinity for both cognate and non-cognate proteins towards the MIPs were dependent on the concentration and the complementarity of their structures and size. This is tentatively attributed to the formation of protein complexes during both the polymerisation and rebinding stages at high protein concentrations. We have used atomic force spectroscopy to characterize molecular interactions in the MIP cavities using protein-modified AFM tips. Attractive and repulsive force curves were obtained for the MIP and NIP (non-imprinted polymer) surfaces (under protein loaded or unloaded states). Our force data suggest that we have produced selective cavities for the template protein in the MIPs and we have been able to quantify the extent of non-specific protein binding on, for example, a non-imprinted polymer (NIP) control surface.

Protein crystallization and biosensor applications of hydrogel-based molecularly imprinted polymers.

We have characterized the imprinting capability of a family of acrylamide polymer-based molecularly imprinted polymers (MIPs) for bovine hemoglobin (BHb) and trypsin (Tryp) using spectrophotometric and quartz crystal microbalance (QCM) sensor techniques. Bulk gel characterization on acrylamide (AA), N-hydroxymethylacrylamide (NHMA), and N-isopropylacrylamide (NiPAM) gave varied selectivities when compared with nonimprinted polymers. We have also harnessed the ability of the MIPs to facilitate protein crystallization as a means of evaluating their selectivity for cognate and noncognate proteins. Crystallization trials indicated improved crystal formation in the order NiPAM

Distinguishing between Contact and Administration of Heroin from a Single Fingerprint using High Resolution Mass Spectrometry.

Fingerprints have been proposed as a promising new matrix for drug testing. In previous work it has been shown that a fingerprint can be used to distinguish between drug users and nonusers. Herein, we look at the possibility of using a fingerprint to distinguish between dermal contact and administration of heroin. Fingerprint samples were collected from (i) 10 patients attending a drug rehabilitation clinic, (ii) 50 nondrug users and (iii) participants who touched 2 mg street heroin, before and after various hand cleaning procedures. Oral fluid was also taken from the patients. All samples were analyzed using a liquid chromatography-high resolution mass spectrometry method validated in previous work for heroin and 6-AM. The HRMS data were analyzed retrospectively for morphine, codeine, 6-acetylcodeine and noscapine. Heroin and 6-AM were detected in all fingerprint samples produced from contact with heroin, even after hand washing. In contrast, morphine, acetylcodeine and noscapine were successfully removed after hand washing. In patient samples, the detection of morphine, noscapine and acetylcodeine (alongside heroin and 6-AM) gave a closer agreement to patient testimony on whether they had recently used heroin than the detection of heroin and 6-AM alone. This research highlights the importance of washing hands prior to donating a fingerprint sample to distinguish recent contact with heroin from heroin use.

Selective extraction of proteins and other macromolecules from biological samples using molecular imprinted polymers.

The accurate determination of intact macromolecules in biological samples, such as blood, plasma, serum, urine, tissue and feces is a challenging problem. The increased interest in macromolecules both as candidate drugs and as biomarkers for diagnostic purposes means that new method development approaches are needed. This review charts developments in the use of molecularly imprinted polymers first for small-molecular-mass compounds then for proteins and other macromolecules. Examples of the development of molecularly imprinted polymers for macromolecules are highlighted. The two main application areas to date are sensors and separation science, particularly SPE. Examples include peptides and polypeptides, lysozyme, hemoglobin, ovalbumin, bovine serum albumin and viruses.

Quantification and confocal imaging of protein specific molecularly imprinted polymers.

We have employed FITC--albumin as the protein template molecule in an aqueous phase molecular imprinted polymer (HydroMIP) strategy. For the first time, the use of a fluorescently labeled template is reported, with subsequent characterization of the smart material to show that the HydroMIP possesses a significant molecular memory in comparison to that of the nonimprinted control polymer (HydroNIP). The imaging of the FITC--albumin imprinted HydroMIP using confocal microscopy is described, with the in situ removal of the imprinted protein displayed in terms of observed changes in the fluorescence of the imprinted polymer, both before and after template elution (using a 10% SDS/10% AcOH (w/v) solution). We also report the imaging of a bovine hemoglobin (BHb) imprinted HydroMIP using two-photon confocal microscopy and describe the effects of template elution upon protein autofluorescence. The findings further contribute to the understanding of aqueous phase molecular imprinting protocols and document the use of fluorescence as a useful tool in template labeling/detection and novel imaging strategies.

Application of an algorithm-driven protocol to simultaneously provide universal and targeted prevention programs.

OBJECTIVE: Our objective was to develop a model to simultaneously prevent eating disorders and weight gain among female high school students. METHOD: Of 188 female 10th graders enrolled in health classes, 174 elected to participate in the current study. They were assessed on-line and decided to participate in one of four interventions appropriate to their risk. RESULTS: The algorithm identified 111 no-risk (NR), 36 eating disorder risk (EDR), 16 overweight risk (OR), and 5 both risks. Fifty-six percent of the EDR and 50% of the OR groups elected to receive the recommended targeted curricula. Significant improvements in weight and shape concerns were observed in all groups. DISCUSSION: An Internet-delivered program can be used to assess risk and provide simultaneous universal and targeted interventions in classroom settings.

The Stanford MediaServer Project: strategies for building a flexible digital media platform to support biomedical education and research.

Medical media collections are growing at a pace that exceeds the value they currently provide as research and educational resources. To address this issue, the Stanford MediaServer was designed to promote innovative multimedia-based application development. The nucleus of the MediaServer platform is a digital media database strategically designed to meet the information needs of many biomedical disciplines. Key features include an intuitive web-based interface for collaboratively populating the media database, flexible creation of media collections for diverse and specialized purposes, and the ability to construct a variety of end-user applications from the same database to support biomedical education and research.