Label-Free Biomarker Sensing in Undiluted Serum with Suspended Microchannel Resonators

摘要

Improved methods are needed for routine, inexpensivenmonitoring of biomarkers that could facilitate earlierndetection and characterization of cancer. Suspendednmicrochannel resonators (SMRs) are highly sensitive,nbatch-fabricated microcantilevers with embedded microchannelsnthat can directly quantify adsorbed mass vianchanges in resonant frequency. As in other label-freendetection methods, biomolecular measurements in complexnmedia such as serum are challenging due to highnbackground signals from nonspecific binding. In thisnreport, we demonstrate that carboxybetaine-derived polymersndeveloped to adsorb directly onto SMR SiO2 surfacesnact as ultralow fouling and functionalizable surfacencoatings. Coupled with a reference microcantilever,nthis approach enables detection of activated leukocytencell adhesion molecule (ALCAM), a model cancernbiomarker, in undiluted serum with a limit of detectionnof 10 ng/mL.