Recent molecular communication (MC) research has integrated more detailed computational models to capture the dynamics of practical biophysical systems. This research focuses on developing realistic models for MC transceivers inspired by spheroids - three-dimensional cell aggregates commonly used in organ-on-chip experimental systems. Potential applications that can be used or modeled with spheroids include nutrient transport in an organ-on-chip system, the release of biomarkers or reception of drug molecules by a cancerous tumor site, or transceiver nanomachines participating in information exchange. In this paper, a simple diffusive MC system is considered where a spheroidal transmitter and receiver are in an unbounded fluid environment. These spheroidal antennas are modeled as porous media for diffusive signaling molecules, then their boundary conditions and effective diffusion coefficients are characterized. Further, for either a point source or spheroidal transmitter, Green's function for concentration (GFC) outside and inside the receiving spheroid is analytically derived and formulated in terms of an infinite series and confirmed by a particle-based simulator (PBS). The provided GFCs enable computation of the transmitted and received signals in the spheroidal communication system. This study shows that the porous structure of the receiving spheroid amplifies diffusion signals but also disperses them, thus there is a trade-off between porosity and information transmission rate. Also, the results reveal that the porous arrangement of the transmitting spheroid not only disperses the received signal but also attenuates it. System performance is also evaluated in terms of bit error rate (BER). Decreasing the porosity of the receiving spheroid is shown to enhance system performance. Conversely, reducing the porosity of the transmitting spheroid can adversely affect system performance.

翻译：近期分子通信（MC）研究已整合更精细的计算模型以捕捉实际生物物理系统的动态特性。本研究聚焦于开发基于球形体（类器官芯片实验系统中常用的三维细胞聚集体）的MC收发器现实模型。可利用或通过球形体建模的潜在应用包括：类器官芯片系统中的营养物传输、癌性肿瘤病灶释放生物标志物或接收药物分子，以及参与信息交换的收发器纳米机器。本文考虑一个简单扩散型MC系统，其中球形发射器与接收器位于无界流体环境中。这些球形天线被建模为扩散信号分子的多孔介质，进而表征其边界条件与有效扩散系数。此外，针对点源或球形发射器，本文解析推导出接收球体内外的浓度格林函数（GFC），将其表述为无穷级数形式，并通过基于粒子的仿真器（PBS）予以验证。所获GFC使得球形通信系统中发射与接收信号的计算成为可能。研究表明：接收球体的多孔结构会放大扩散信号但也会使其弥散，因此孔隙率与信息传输速率之间存在权衡关系。同时，结果揭示发射球体的多孔排列不仅会使接收信号弥散，还会使其衰减。系统性能亦通过误码率（BER）进行评估。降低接收球体孔隙率可提升系统性能，反之，降低发射球体孔隙率则可能对系统性能产生不利影响。