Nanocarrier-Based Approaches for Intracellular Protein Transport in Therapeutic Applications
Intracellular protein delivery is becoming a breakthrough tool in biotechnology and medicine, opening new possibilities for gene editing, enzyme replacement, immunomodulation, and targeted therapies. Traditional techniques like microinjection and electroporation can deliver proteins into the cytosol, but their low throughput, risk of cellular damage, high cost, and limited clinical use make them far from ideal. Advances in nanotechnology have introduced a broad range of nanocarrier platforms such as polymeric and lipid nanoparticles, hybrid lipid–polymer systems, dendrimers, extracellular vesicles, and self-assembling protein nanostructures that help overcome many of these limitations. These carriers enhance protein stability, protect them from enzymatic degradation, improve cellular uptake, and enable controlled or stimulus-responsive release. Key features of nanocarriers—including particle size, surface charge, material type, and ligand functionalization—play central roles in how they move within cells and achieve endosomal escape. Nanocarrier systems have proven efficient delivery of therapeutic enzymes, CRISPR-Cas9 ribonucleoprotein complexes, and fluorescent proteins for imaging. Recent innovations such as biomimetic coatings, fluorinated or heterocyclic polymers, and cell-penetrating peptide modifications have further improved delivery precision and biocompatibility. Despite these advances, challenges like cytotoxicity, immune clearance, manufacturing hurdles, and regulatory complexity continue to shape the field. This chapter describes recent nanocarrier technologies in protein delivery nanocarriers, highlights the design principles that underpin effective intracellular transport, and outlines future directions for developing safe, stable, and clinically meaningful protein-based nanomedicines.