Molecular Communication Is the Internet of Brain Missing Key: A Comprehensive Overview of Background Technologies and the Generic Framework

ABSTRACT Amidst the explosive growth of neural technologies like Brain‐Computer Interfaces (BCIs) and Brain–Brain Interfaces (BBIs), persistent barriers, invasive surgeries, soaring costs, and chronic biocompatibility issues, continue to stifle true cognitive connectivity. Enter the Molecular Communication (MC)‐based Internet of Brains (IoB): a transformative, fully non‐invasive paradigm that harnesses the elegance of biological signaling for affordable, seamless brain networking. In this pioneering work, we unveil the inaugural four‐layered MC‐IoB framework, ingeniously utilizing molecular messengers to forge secure, noise‐immune pathways for direct mind‐to‐mind exchanges, all without cumbersome metallic implants. Through cutting‐edge Digital Twin simulations, we rigorously evaluate and showcase MC's dominance over conventional Radio Frequency (RF) systems in speed, safety, and efficiency. Our formal security proofs, grounded in advanced logic models, affirm MC‐IoB as the ultimate fortress against cyber intrusions in neural realms. Moreover, we debut the “Cell–Cell Interface” (CCI), a game‐changing innovation that empowers direct molecular dialogues between cells, catapulting possibilities in brain enhancement, precision medicine, and hybrid bio‐digital ecosystems. This visionary blueprint not only shatters existing limitations but ignites a new era of ethical, scalable IoB, where human cognition evolves unbound.