We show the fabrication and characterization of a new generation of suspended microchannel resonators (SMRs) with integrated piezoelectric (PZE) actuation. We study resonance frequency, quality factor and frequency stability of singly-clamped hollow devices. Measurements of empty devices in air and vacuum show no significant difference in the frequency stability whereas the quality factor differs by a factor of 19x. The same analysis are performed when the SMRs are filled with DI water. In this case the quality factor between air and vacuum environment differs 11x, while the frequency stability is almost identical for integration times below 300 ms. This independence of the frequency stability on the quality factor suggests that vacuum encapsulation is not strictly necessary in order to achieve state of the art sensing performances when analyzing fluidic samples, ultimately simplifying the experimental setup.