We describe the rapid, label-free detection of Influenza A viruses using a cantilever transducer modified with a synthetic sialylglycopolymer receptor layer. Surface stresses induced by viruses binding to the receptor layer were used as the analytical signal. The synthetic sialylglycopolymer receptor layer can be used in nanoscale strain-gauge cantilever transducers for highly sensitive virus detection. Strain-gage transducers using such sensor layers exhibit long lifetimes, high sensitivities, and possible regeneration. Nanomechanical cantilever systems using optical detectors were used for the surface stress measurements. We demonstrated the positive, label-free detection of Influenza A at concentrations below 10(6) viruses per ml. In contrast to hemagglutination assays, cantilever sensors are label free, in situ, and rapid (less than 30 min), and they require minimal or nearly no sample preparation.