A Software-Defined Perspective on Molecular Networking in the Internet of BioNanoThings

The Internet of BioNanoThings (IoBNT) envisions networks of nanoscale biological entities, called bionanomachines, capable of sensing, processing, and communicating within living systems. These entities rely on molecular communication (MC), a biologically compatible method that uses biochemical signals instead of electromagnetic waves. While promising for intra-body applications such as diagnostics and targeted therapy, MC faces inherent limitations, including noise, limited range, and lack of programmability. This work proposes a novel integration of Software-Defined Networking (SDN) principles into MC systems to address these challenges. By mapping SDN components, such as flow tables, match fields, and control logic, to biological counterparts, we introduce the concept of Bio-SDN: a programmable, layered architecture for orchestrating bionanomachines. DNA-based messaging and bacterial carriers enable addressable control channels, while synthetic biology tools such as logic gates and promoter tuning support decision-making and prioritization. Applications include real-time health monitoring, adaptive drug delivery, and environmental biosensing. The paper also discusses fault management strategies and outlines key challenges in reliability, mutation control, bio-cyber interfacing, and security. Bio-SDN offers a scalable framework for managing biological networks, paving the way for intelligent, responsive systems embedded within living organisms.