In the present article, we focus on the forced vibration and control analysis of functionally graded (FG) graphene-polymer composites bonded with piezoelectric layers considering strong electric fields. Different non-uniform gradient distributions of graphene platelets (GPLs) are assumed through the thickness direction. The Modified Halpin-Tsai micromechanics model is used to obtain the effective material properties of GPL/polymer composites. Electromechanical coupling of piezoelectric layers is described by two rotationally invariant non-linear constitutive relations. A four-node shell element considering transverse shear effect based on the Reissner-Mindlins hypothesis has been developed for forced vibration and control analysis of smart FG-GPL/composites using the principle of virtual work considering nonlinear material law for the piezoelectric layers. The developed element is verified and compared with the numerical results those available in the literature. Different configurations of FG-GPL composite shells have been analysed and discussed to compare in terms of settling time, first resonance frequency and absolute amplitude corresponding to first resonant frequency by carrying out time and frequency response analysis, and the effects of weight fraction of GPLs on vibration response of such shell structures are also discussed. The influence of electromechanical nonlinear constitutive relations is also presented and discussed by performing active control analysis on different FG-GPL composite shell structures. Moreover, the results show that the GPL distribution and weight-fraction of GPLs have a significant effect on the vibration and damping characteristics of the FG-GPL composite shell structures.

We have designed and characterized a poly-dimethyl-siloxane (PDMS) based microfluidic device called MiMiC™ that enables time-lapse study of cell migration. Cell migration is a key step of malignant metastasis during cancer progression. The device mimics the narrow confines the cells need to traverse and the microenvironments that are similar to the ones inside human body. Photolithography and soft lithography processes were used to fabricate the microfluidic devices. The device consists of two separate chambers connected by microfluidic channels allowing introduction of cells in one chamber and chemoattractants in the other. The response of lung-metastasized prostate cancer (PC-3-ML) cells and their migration response to chemoattractants were observed and analyzed. The numbers of cells under migration were determined from time-lapse images and compared to control groups. Our microfluidic assays provide advantages over the traditional Boyden chambers such as time-lapse observation, use of smaller amounts of reagents and direct assessment of cells under migration.