Ling WangFollow

Document Type



Doctor of Philosophy (PhD)



First Advisor's Name

Bruce McCord

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Anthony DeCaprio

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Piero Gardinali

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Nelly Mateeva

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Anthony McGoron

Fifth Advisor's Committee Title

Committee member

Sixth Advisor's Name

Yi Xiao

Sixth Advisor's Committee Title

Committee member


uPADs, Drugs of abuse, Colorimetric reagents, AuNPs, Aptamer

Date of Defense



Over the years, colorimetric reagents and immunology have been widely used in screening tests for illicit drugs; however, the test kits are not always convenient for field use and often require the user to mix and develop a specific set of reagents. In our project, we have been working on alternative platforms based on paper microfluidic devices (uPADs) for field testing. These devices utilize wax channels printed on paper to direct the analyte towards a specific set of chemical reagents. Using the procedure, we have developed a six-channel chip that adapts known colorimetric reagents targeting cocaine, opiates, amphetamines and ketamine for multiplex detection. For more sensitive and specific determinations than the colorimetric reagents, we have also developed a paper device that utilizes the interaction between gold nanoparticles and drug specific aptamers.

The µPADs using colorimetric reagent are designed as a six-channel multiplexed system. Sequences of different reagents applied to each channel to produce a series of reactions and the color changes appear at the end of each channel. The entire process takes less than five minutes. The adjusted reagents produce specific color changes for seized drugs on the paper microfluidic devices. Procedures have been developed for the detection of cocaine, ketamine, codeine, ephedrine, morphine, amphetamine, methamphetamine, and MDMA. These devices have been tested for sensitivity, specificity and stability against a variety of potential interferences and test conditions.

Gold nanoparticles (AuNPs)/ aptamers µPADs were developed to detect cocaine. The presence of cocaine cause the binding with aptamers, and the gold nanoparitcles produced a salt-indicated aggregations and gave a color change of AuNPs from red to black. The absence of cocaine allowed the aptamers freely to bind gold nanoparticles, and no color change occured. The device had a preliminary validation of sensitvity and specificity against a variety of potential interferences.

The use of paper microfluidic devices permits the development of rapid, inexpensive and easily operated tests for drug samples in the field. They present a safe and convenient presumptive tool that can be used in the field.





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