Modeling a composite molecular communication channel

© 1972-2012 IEEE. This paper deals with development of diffusive propagation model for molecular communication in composite biological microenvironments with multiple regions (or layers) each with distinct diffusion properties to understand the transport of information molecules. We propose generalized analytical and simulation approaches for modeling a composite, diffusive, and molecular communication channel for arbitrary placement of the transmitting and receiving nano-machines. We derive a generalized closed-form expression for the channel impulse response of a three dimensionally (3-D) diffusive medium that has 'N' regions. The results from the proposed particle-based simulator are validated with the exact analytical solution. The pulse peak amplitude, pulse peak time, and pulse width are derived to evaluate the system performance using both analytical and simulation approaches. It is shown that the channel impulse response and other communication metrics are significantly affected by the diffusion coefficients, region thickness, interface properties, and the positions of transmitter and receiver nano-machines with respect to the interfaces

Modelling of Implantable Drug Delivery System in Tumor Microenvironment Using Molecular Communication Paradigm

© 2013 IEEE. Local delivery of anticancer drug in tumor using miniaturized implants over a prolonged period of time is a powerful treatment strategy that provides lower toxicity and higher drug bioavailability compared to conventional systemic chemotherapy. Prediction of anticancer drug distribution in tumor following implantation of the drug implant is necessary to improve and optimize the implantable drug delivery systems (IDDSs). In this paper, we develop mathematical and stochastic simulation models for the prediction of spatiotemporal concentration of anticancer doxorubicin following implantation of a dual-release implant in an isolated tumor microenvironment (TME). Our model utilizes mathematical convolution of the channel impulse response (CIR) with the drug release function based on the abstraction of molecular communication. The derived CIR can be used to obtain drug concentration profile in the surrounding tissue for various release profiles and different anticancer drugs. We derive closed-form analytical expression for anticancer drug concentration. The required release rates are obtained by fitting the experimental data on dual-release implant available in the literature to a mathematical expression. In addition, we also present a particle-based stochastic simulator and compare the results with those predicted by the analytical model. The accuracy of predictions by both the models is further verified by comparing with the published experimental data in the literature. Both the proposed models can be useful for the design optimization of the implantable drug delivery systems (IDDSs) in tumors and other tissues and can potentially reduce the number of animal experiments thus saving cost and time

Comparison of reception mechanisms for molecular communication via diffusion

© 2018 IEEE. Molecular communication paradigm enables nanomachines or biological cells at nano/micro scales to communicate using chemical molecules. In this paper, we study different reception mechanisms in an unbounded 3-D biological medium for diffusion-based molecular communication system and compare their performances. The number of received molecules (i.e., number of activated receptors) is first analytically evaluated and then validated using a particle-based simulator developed by us. We address various receiver models, viz., passive, irreversible partially or fully absorptive, and a more general reversible receivers. The peak amplitude and peak time for passive and fully absorptive receivers are evaluated. The impact of various parameters, e.g., diffusion coefficient, separation distance, forward/backward reaction rates, on the received signal are examined

Wideband RF power meterwith frequency range up to 10 GHz

Radio frequency (RF) power meter is useful device for design of wireless communication systems and for many other applications. It is important device for RF design engineers in order to measure the level (strength) of electromagnetic (EM) field at any point from transmitter. For example, using RF meter, we can check if the EM field is below the specific allowed level for human health. Moreover, we can use it in test area at far-field region after installing the antenna and transmitter. In this paper, wideband RF power meter is designed based on hardware and software with ability to measure any RF signal in frequency range 0-10 GHz. It is a portable RF meter with small size. Moreover, it has LCD, LEDs bar as a display options, and buzzer as an alarm when the signal level exceeds specific threshold

Influence of Tissue Anisotropy on Molecular Communication

© 2019 IEEE. Many biological tissues inside the human body exhibit highly anisotropic diffusion properties; for example, tissues of the nervous system and white matter in the brain. Here, we present an improved stochastic molecular communication framework to model interaction between bionanomachines in three-dimensional (3D) anisotropic brain micro-environment. The results obtained using stochastic particle-based simulation model are validated with analytical expressions. We also derive expressions for peak amplitude and peak time for the received molecular signal. The results demonstrate that the channel impulse response in anisotropic biological media depends significantly on the diffusion tensor as well as on the locations of the nanomachines

Modeling of Ligand-Receptor Protein Interaction in Biodegradable Spherical Bounded Biological Micro-Environments

© 2013 IEEE. In this paper, we propose a generalized model for the Ligand-Receptor protein interaction in 3-D spherically bounded, diffusive biological microenvironments using molecular communication paradigm. Modeling a targeted cell as a receiver nano-machine, we derive analytical expressions for the Green's function as well as for the expected number of the activated receptors. The molecular degradation in the environment due to enzymatic effects and the changes in pH levels are included via the first-order degradation reaction mechanism. A second-order reversible reaction mechanism is employed to model the reception process that involve the reaction of ligands to activate the receptor proteins lying on the receiver surface to form ligand-receptor complexes. We also present a particle-based simulator that incorporates the reversible reaction of molecules with the receptors present on the surface of a receiver that is located inside a bounded, 3-D microfluidic environment. Our simulations also include molecular degradation and boundary absorption of the ligands due to collision. The simulation results show perfect agreement with the results obtained from the analytical, bounded, and 3-D spherical model of the medium. The proposed models can be used for accurate prediction of the drug concentration profiles and number of activated receptors at any targeted cell