Paper Replaces Nitrocellulose in New Rapid Test for Morphine

A recent paper described the use of paper as the support material for a rapid diagnostic test for detection of morphine in saliva.

Investigators at the biomedical company VTT (Espoo, Finland) used morphine as a model analyte to examine the possibility of using cellulose, physically modified by papermaking and converting techniques, as a capillary matrix in a lateral flow type of diagnostic assay. In this case, paper replaced the generally used nitrocellulose support material.

The investigators developed a "sandwich" lateral flow assay that incorporated antibody Fab fragments as sensing molecules and employed gold nanoparticle visual detection. Inkjet printing was used to pattern sensing biomolecules as detection zones on the paper.

Results were compared with those achieved by using nitrocellulose as the test support material. Possible interference from the sample matrix on assay quality was investigated with spiked oral fluid samples.

Under optimized conditions, a visually assessed limit of detection for the assay was one nanogram per milliliter, indicating that the paper-based test devices developed in this work could perform screening for drugs of abuse and could fulfill the requirement for a sensitive assay in diagnostically relevant ranges.

"In 2010, we proved that the VTT method works in a hemoglobin assay. Through our continued development efforts, we wanted to confirm that the method also works in mass-production of more demanding tests. Morphine as a small-sized molecule places major requirements on the analytical performance of the test. In the future, the new method will also present an opportunity to simultaneously analyze other drugs of abuse and residues of pharmaceuticals and their metabolites from one and the same sample,” said Dr. Tomi Erho, principal scientist at VTT.

Details of the paper-based morphine test were published in the September 2014 issue of the journal Analytical and Bioanalytical Chemistry.

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