We recenlty published an open acces journal paper on microvales design together with Fraunhofer EMFT:

• Durasiewicz, C.P.; Güntner, S.T.; Maier, P.K.; Hölzl, W.; Schrag, G. Piezoelectric Normally Open Microvalve with Multiple Valve Seat Trenches for Medical Applications. Appl. Sci. 2021, 11, 9252. https://doi.org/10.3390/app11199252