Diamond-based materials are increasingly investigated in neuroscience and neuroengineering because of their tunable surface chemistry, mechanical robustness, electrochemical stability and photostability. This review compares particulate nanodiamonds (NDs), fluorescent NDs, conductive and nanocrystalline diamond electrodes, and NV-containing diamond sensors across neural sensing, imaging, neurochemical monitoring, neural interfacing, regenerative engineering and experimental therapeutic applications. We examine how synthesis, particle size, purity, aggregation, surface chemistry and defect structure influence application-specific performance, biological interactions, biodistribution and safety. Translational potential is assessed according to the available evidence, systemic exposure, technical maturity, manufacturing requirements and regulatory complexity. Localized diagnostic and neurochemical-sensing applications may offer comparatively plausible near-term pathways because they can reduce dependence on systemic delivery. Implantable neural electrodes and retinal interfaces also avoid some systemic barriers but remain predominantly supported by preclinical evidence. ND-based central nervous system (CNS) drug delivery, glioblastoma treatment, neurodegenerative scaffolds and mammalian quantum-neuronal sensing remain at earlier experimental stages. Key barriers include formulation-dependent biocompatibility, sensitivity in complex tissues, blood-brain barrier delivery, long-term biodistribution and clearance, manufacturing reproducibility, GMP-compatible scale-up and regulatory qualification. Although some of these limitations may be reduced through material and process optimization, comparative validation and stronger long-term safety evidence are still required for clinical translation. STATEMENT OF SIGNIFICANCE: Diamond-based materials are increasingly finding their way into neuroscience and neuroengineering by bridging the gap between advanced nanotechnology and living neural systems. This review highlights the versatility of distinct diamond structures-ranging from detonation nanodiamonds and fluorescent defect centers to conductive boron-doped electrodes-across applications like biosensing, neurochemical monitoring, neural interfacing, and targeted therapy.
