Cornell Research Foundation Inc.

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Richard Allen Durst

Daniel Martorell-Pena

Stuart Graham Reeves

The present invention relates to a method for making a test device for detecting or quantifying an analyte in a sample. This method involves contacting a membrane with a mixture including derivatized, marker-loaded liposomes, and substantially dehydrating the mixture on the membrane under vacuum pressure at a temperature of from about 4&#xb0; C. to about 80&#xb0; C., wherein said mixture further includes one or more sugars in an amount sufficient to promote the stability of the liposomes during dehydration and rehydration. The present invention also relates to a test device and method for detecting or quantifying an analyte in a sample. The test device includes a membrane which includes an immobilized liposome zone, wherein the immobilized liposome zone has bound thereto dehydrated, derivatized, marker-loaded liposomes dehydrated under vacuum pressure at a temperature of from about 4&#xb0; C. to about 80&#xb0; C. from a mixture which includes one or more sugars in an amount sufficient to promote the stability of the liposomes during dehydration and rehydration.

Dehydration/rehydration of derivatized, marker-loaded liposomes on a test device and method of use thereof

Method of making a test device

A test device for detecting or determining an analyte in a test solution includes an absorbent material having separate contact, competitive binding, and measurement portions. The contact portion is positioned for contact with and uptake of the test solution. The competitive binding portion has a binding material for the analyte non-diffusively bound thereto. The measurement portion has a receptor for the analyte and marker-encapsulating liposomes non-diffusively bound thereto. In a method for using the test device, a solution containing the analyte and the analyte-liposome conjugate is allowed to traverse the absorbent material from the contact portion through the competitive binding portion and on through the measurement portion of the absorbent material. The amount of marker in the measurement portion of the absorbent material, following traversal by the test solution, is then determined as a measure of the analyte in the sample. Liposomes encapsulating an electroactive marker are used in conjunction with a test device as described above but which includes an electrochemical measurement portion in place of the measurement portion described above. Test devices and methods employing electrochemical detection or quantification of an electroactive marker corresponding to the amount of analyte in a sample may be either amperometric or potentiometric.

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Geneva, NY, United States of America

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