Autonomous capillary system for one-step immunoassays.
Autonomous capillary systems (CSs), in which liquids are transported owing to capillary forces, have been previously used to perform fast and sensitive multi-step immunoassays using minute volumes of analyte. CSs for diagnostic applications have different requirements than CSs that are used as a research tool in life sciences, where a high flexibility and performance prevail over ease of use and portability. In this paper a proof-of-concept for one-step immunoassays based on CSs is demonstrated. This proof-of-concept is based on preloading detection antibodies (dAbs) on the flow path of analytes and redissolving these antibodies to form dAb-analyte complexes, which can be detected using fluorescence downstream on accurately patterned capture antibodies. A user therefore only needs to load a sample at the beginning of a CS and obtains the result of the assay using a conventional fluorescence microscope or scanner. As an example, C-reactive protein was detected in human serum at clinical concentrations within 10 min and using only microL of sample.
Zimmermann
Martin
M
Zurich Research Laboratory, IBM Research GmbH, Säumerstr. 4, 8803, Rüschlikon, Switzerland, emd@zurich.ibm.com.
Hunziker
Patrick
P
Delamarche
Emmanuel
E
D000818:Animals; D000906:Antibodies / Q000737:chemistry*; D002097:C-Reactive Protein / Q000032:analysis*; D005453:Fluorescence; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D012680:Sensitivity and Specificity
D000906:Antibodies; D002097:C-Reactive Protein