Modeling of an Optically Heated MEMS-Based Micromechanical Bimaterial Sensor for Heat Capacitance Measurements of Single Biological Cells

Abstract

Detection of thermal activities of biological cells is important for biomedical and pharmaceutical applications because these activities are closely associated with the conformational change processes. Calorimetric measurements of biological systems using bimaterial microcantilevers (BMC) have increasingly been reported with the ultimate goal of developing highly sensitive and inexpensive techniques with real-time measurement capability techniques for the characterization of dynamic thermal properties of biological cells. BMCs have been established as highly sensitive calorimeters for the thermal analysis of cells and liquids. In this paper, we present a simulation model using COMSOL Multiphysics and a mathematical method to estimate the heat capacity of objects (treated here as a biological cell) placed on the surface of a microcantilever. By measuring the thermal time constant, which is obtained from the deflection curve of a BMC, the heat capacity of a sample can be evaluated. With this model, we can estimate the heat capacity of single biological cells using a BMC, which can potentially be used for the thermal characterization of different biological samples.

Solution Properties of a New Dynamic Model for MEMS with Parallel Plates in the Presence of Fringing Field

“…We observe that, in (20), there is no contribution due to the fringing field, electrostatic phenomenon, according to which, once V is applied, the bending of E occurs at the edges of the MEMS, while, at its center, E remains parallel. Furthermore, the electrostatic capacity of the MEMS undergoes strong variations in its amplitude that are not easy to evaluate; therefore, empirical formulation has to be exploited [1,59].…”

“…We note that, in the recent past, many authors have extensively studied model (20), obtaining interesting conditions on global existence where dangerous bifurcation phenomena took place [1,59]. Particularly, in [60], it was proved that (20), besides admitting a N-dimensional generalization, provided interesting conditions of existence particularly useful for the numerical recovering of the deformable plate profile.…”

“…This has made it possible to highlight a strong synergy between undoubted theoretical skills and industrial realities by carrying out technological transfers that were previously prohibitive [9][10][11], also with manufacturing imperfections (which, notoriously, affect the operation of MEMS devices), if taken into account during the modeling and design phases [12,13] (i.e., by means of asymptotic homogenization techniques [14]). These devices, nowadays, considered "intelligent", are able to combine electrical, electronic, mechanical, and optical effects by managing highly complex industrial processes [15][16][17][18][19][20], especially when nonlinear dynamic characteristics of MEMS devices are involved, so that the relative simulation accuracy is low and cannot meet the needs of design applications [21,22]. Modern industrial technologies allow the production of micro-products, even with complex geometries, in which the deformable elements take on particular connotations and characteristics.…”

Cell Temperature Measurement for Biometabolism Monitoring

“…In order to further improve the accuracy, a dual-support resonator is set on the cantilever beam (Figure ), which has a larger temperature coefficient than the cantilever cavity, and the temperature resolution and thermal resolution are improved to 79 μK and 1.90 nW, respectively . In a recent report, Alodhayb proposed a mathematical model based on a CBC sensor to estimate the heat capacity of a single biological cell and may be extended to the analysis of thermal properties of different biological samples …”

Electrostatic-Elastic MEMS with Fringing Field: A Problem of Global Existence

“…They are devices of various kinds (mechanical, electrical, and electronic) integrated in a highly miniaturized form onto the same substrate of semiconductor material (for example, silicon [3][4][5]) that combine the electrical properties of the semiconductor with the opto-mechanical properties. These are therefore "intelligent" systems that combine electrical [6], electronic [7], fluid management [8], optical [9], biological [10], chemical [11], and mechanical [12] functions in small spaces, associating all the possible management functions of a process to sensors and actuators [13].…”