The Dawn of Bio-Hybrid Intelligence: Dr. Kumar Mritunjay's Groundbreaking 3D Neural Network Device

In a fusion of biology and electronics that echoes science fiction, Indian-origin researcher Dr. Kumar Mritunjay has spearheaded the creation of a revolutionary 3D mini-brain chip. This device, known as the 3D micro-instrumented neural network device or 3D-MIND, integrates living neurons with advanced microelectronics, enabling unprecedented bidirectional communication between biological tissue and silicon-based systems. Published in the prestigious journal Nature Electronics on April 23, 2026, the innovation promises to transform neuromorphic computing—hardware designed to mimic the human brain's architecture—and accelerate neuroscience research into disorders like Alzheimer's, epilepsy, and Parkinson's.

The platform features approximately 70,000 biological neurons cultured on a flexible 3D mesh scaffold embedded with dozens of microscopic electrodes. These electrodes not only record electrical activity from the neurons but also stimulate them, allowing researchers to observe and influence neural dynamics in real time. Unlike traditional 2D brain-on-a-chip models confined to flat surfaces, this 3D structure permits neurons to grow and connect in all directions, replicating the complex, volumetric architecture of the human brain more faithfully.

Dr. Mritunjay's work addresses critical limitations in current technologies. Previous systems struggled with long-term stability, often degrading after weeks. Here, the device maintains viable neural networks for over six months, enabling longitudinal studies of synaptic plasticity—the strengthening or weakening of connections between neurons, which underlies learning and memory.

Dr. Kumar Mritunjay: From IIT Kharagpur to Princeton's Cutting Edge

Dr. Kumar Mritunjay, affectionately known as 'Mito' among colleagues, embodies the global impact of Indian higher education. A BTech graduate from the Indian Institute of Technology (IIT) Kharagpur, he pursued a dual PhD in Electrical and Computer Engineering and Neuroscience at Princeton University. Currently a postdoctoral research associate in Princeton's Department of Electrical and Computer Engineering and the Omenn-Darling Bioengineering Institute, Mritunjay's career bridges disciplines.

His research interests lie at the intersection of electronics and neuroscience, focusing on electrode designs for precise neuronal signal detection. As a first-generation international STEM student, Mritunjay has mentored peers on navigating cultural challenges and academic pressures, reflecting his commitment to inclusive science. Supervised by Princeton professors Tian-Ming Fu and James C. Sturm, the project was fabricated at the Princeton Materials Institute, funded by Princeton's innovation grants.

Mritunjay's achievement underscores the IIT system's role in nurturing talent that excels globally. IIT Kharagpur, renowned for its engineering rigor, provided the foundational skills that propelled him to this frontier research, inspiring current Indian students in neuromorphic computing and bioengineering.

Technical Breakdown: Engineering the 3D Mini-Brain Chip

The 3D-MIND device begins with advanced microfabrication: a scaffold of microscopic metal wires and electrodes coated in a thin, flexible epoxy layer. This structure, mere microns thick, supports neuron growth without impeding their natural expansion. Neurons, derived from stem cells, are suspended in Matrigel—a gelatinous matrix mimicking extracellular environment—and seeded onto the scaffold at densities yielding ~70,000 cells.

Over weeks, neurons differentiate, form synapses, and self-organize into networks. Embedded platinum electrodes (dozens per device) enable multi-plane recording of action potentials—brief electrical spikes signaling neural communication—with high spatiotemporal resolution. Stimulation pulses modulate activity, strengthening specific connections via Hebbian learning principles: 'neurons that fire together wire together.'

The system's programmability shines in reservoir computing tasks, where input patterns (spatial/temporal electrical sequences) are echoed through the network and decoded by algorithms. Tests demonstrated accurate pattern discrimination, validating its computational potential.

Surpassing 2D Limitations: Why 3D Matters

Conventional brain-on-chip platforms use 2D monolayers, restricting neuron growth to planar surfaces. This fails to capture the brain's 3D cytoarchitecture, where dendrites and axons extend volumetrically, fostering rich connectivity. 3D-MIND overcomes this with its porous scaffold, promoting isotropic growth and physiological densities (~10^4-10^5 neurons/mm³).

Stability is another leap: 2D cultures degrade due to necrosis from poor nutrient diffusion. The 3D design ensures vascular-like perfusion, sustaining networks for months. Fine-grained electrophysiology reveals emergent behaviors like bursting patterns, absent in flat models.

For Indian researchers, this validates scaling organoid tech. Institutions like IISc Bangalore's NeuRonICS Lab are advancing neuromorphic chips, aligning with global trends.

Photo by Google DeepMind on Unsplash

Experimental Breakthroughs: Pattern Recognition and Learning

Over six months, the team monitored connectivity maps, observing synaptic pruning and potentiation. Pharmacological tests (e.g., bicuculline for excitation) elicited realistic responses, confirming functional maturity.

Chronic stimulation tuned connections, forming reservoir networks for biocomputing. Trained on pulse patterns, the system distinguished inputs with high fidelity, rivaling silicon AI but at biological energy scales (brain uses ~20W vs. AI's megawatts). Fu notes, "Our brain consumes only one millionth the power of today’s AI." Mritunjay adds, "It uncovers brain computing secrets and aids disease treatment."

Revolutionizing AI: Towards Energy-Efficient Neuromorphic Systems

Neuromorphic computing seeks brain-like efficiency. Traditional von Neumann architectures bottleneck at data movement; spiking neural networks (SNNs) emulate pulses. 3D-MIND advances bio-hybrid SNNs, where wetware (neurons) handles parallel processing.

Applications include edge AI for IoT, reducing power for mobiles. Scaling to millions of neurons could outperform GPUs in tasks like speech recognition. In India, IISc's memristor (4.1 TOPS/W) and Moonshot brain co-processors complement this.

Link to paper: Nature Electronics publication.

Transforming Neuroscience: Modeling Diseases and Therapies

3D-MIND enables disease modeling by perturbing networks (e.g., amyloid for Alzheimer's). Long-term imaging tracks degeneration; stimulation tests interventions. Brain-machine interfaces (BMIs) benefit from stable recordings for prosthetics.

Indian neuroscience surges: IISc's BMI for attention, neuromorphic workshops. Mritunjay's IIT roots inspire collaborations, e.g., IIT Madras analog chips.

India's Growing Neuromorphic Ecosystem

India leads with IISc's NeuRonICS Lab pioneering reconfigurable neuromorphic ICs, 2026 memristors, and Moonshot BMI project. IITs contribute: IIT Madras SNNs, IIT Kharagpur alumni like Mritunjay. Government NEP 2020 boosts interdisciplinary research.

Challenges: funding, fabs. Opportunities: bio-hybrid chips for healthcare AI.

Photo by Google DeepMind on Unsplash

Challenges, Ethics, and the Road Ahead

Scalability (to cortex-like sizes), biocompatibility, ethics (neural sentience?) remain. FDA-like regs needed for BMIs. Future: hybrid supercomputers, personalized medicine.

Princeton plans scaling; Indian labs eye indigenous versions. Visit Princeton announcement for visuals.

Global Impact and Call to Indian Researchers

Mritunjay's feat spotlights diaspora contributions. Indian universities can leverage via TNE, joint labs. Explore opportunities in neuromorphic research.