Abstract

Asad Hameed Alnajar*

ABSTRACT

Objective: Functionally modified nanoparticles (FNPs) have emerged as pivotal vectors in biomedical nanomedicine, offering tailored physicochemical attributes that enhances drug delivery, diagnostic imaging, targeted gene transport and oncological therapeutics. Surface Functionalization utilizing synthetic or biological macromolecules-including polymers, monoclonal antibodies, functional peptides, lipids and biomolecules-impares colloidal stability, prolongs systemic circulation, and maximizes bio-distribution and cellular uptake efficiency. This review critically evaluates the primary structural classes of FNPs, their endocytic internalization pathways, and subcellular distribution, while elucidating the toxicological paradigms governing nanoparticle-induced cellular and genomic perturbation in mammalian systems. This review uniquely integrates nanoparticle surface functionalization profiles with microRNA dysregulation, chromatin remodeling, and structural chromosomal instability (CIN) mechanisms, while providing a critical evaluation of methodological artifacts and predictive computational models. Mechanism: Cellular processing of FNPS initiates specific biological cascades dictated by surface architecture and particale kinetics. Intracellular toxicity is predominantly driven by excess production of reactive oxygen species(ROS), which overwhelms endogenous antioxidant, defenses and triggers mitochondrial membrane depolarization, repirotary chain disruption, lipid peroxidation, and protein carbonylation. At the nuclear level, toxic events proceed via direct and indirect pathways: ultra-small particles penetrate nuclear pore complexes or interact with naked chromatin during mitosis, whereas cytoplasmic oxidative cascades induce single- and double-strand DNA cleavage, alter DNA methyltransferase (DNMT) dynamics, dysregulate oncogenic microRNAs(e.g. miR-21 and miR-155), and disrupt spindle assembly checkpoints (SAC). Finding in brief: Exposure to reactive FNPs induces systemic intracellular distress, culminating in structural membrane destrabilization, chronic pro-inflammatory signaling, telomeric guanine oxidation, and micronucleus formation- a primary biomarker of clastogenic and aneugenic chromosomal instability(CIN). Conversely, strategic surface modification enables localized hyperthermic, photothermal and redox- responsive therapeutic interventions. Recent advances in safe-by-design (SbD) nanotechnology, biodegradable polymeric matrics, provide viable pathways to decouple therapeutic efficacy from cellular injury. Conclusions: While surface-functionalized nanoparticles offer transformative clinical utility, significant translational challenges persist regarding chronic bio-accumulation, off-target biodistribution, environmental ecotoxicity, and long term genomic instability. Comprehensive multi-omics profiling, predictive computational toxicology, and physiologically relevant three- dimensional (3D) tissue models are imerative to advance safe clinical translation.