Emerging non-endocytic transmembrane delivery strategies for precision medicine

Conventional endocytosis-mediated delivery is limited by poor endosomal escape efficiency, making intracellular delivery of therapeutic biomacromolecules a long-standing challenge in modern biomedical research. The low endosomal escape efficiency of traditional endocytosis-dependent pathways remains a fundamental bottleneck restricting the clinical translation of therapeutic biomacromolecules. A review published in Biomedical Analysis focuses on emerging non-endocytic transmembrane delivery strategies, which bypass canonical cellular uptake routes to achieve direct cytosolic delivery of mRNA, proteins, nucleic acids, and gene-editing tools. Led by Dr. Yang Liu from the Institute of Energy, Hefei Comprehensive National Science Center, the review systematically outlines research progress in physical, bioengineered, and biomimetic delivery platforms, and discusses their application prospects in gene therapy, macromolecular drug delivery, and cellular engineering.

A new generation of intracellular delivery technologies

The review summarizes recent advances in several emerging non-endocytic delivery platforms, arranged in chronological order of development: physical temporary membrane permeabilization methods, cell-penetrating peptides, membrane fusion systems, virus-like particles, phase-separated carriers, and engineered biological nanomachines.

Physical approaches, such as electroporation, sonoporation, photothermal methods, and mechanical membrane modulation, create reversible transient pores in cell membranes to facilitate molecular transport. Advances in micro- and nanoscale engineering are helping improve delivery efficiency while minimizing cellular damage.

Biomimetic strategies, spanning peptide-based carriers to virus-inspired delivery systems, draw inspiration from natural biological processes to achieve more efficient intracellular transport. As the earliest bioengineered non-endocytic modality, cell-penetrating peptides laid the foundation for subsequent biomimetic designs. Membrane fusion systems and virus-like particles further evolved by leveraging natural membrane interaction mechanisms. Phase-separated carriers, emerging in recent years, have expanded the biomimetic toolbox with unique phase transition properties. Meanwhile, engineered biological nanomachines represent a particularly innovative direction by mimicking natural molecular delivery mechanisms to introduce functional biomolecules into cells.

Unlocking new possibilities for precision medicine

Efficient intracellular delivery is a critical requirement for many emerging biomedical applications. For gene-editing technologies such as CRISPR systems, therapeutic molecules must reach specific intracellular locations to perform their functions. Similarly, mRNA therapeutics, protein-based therapies and cellular engineering approaches depend on reliable methods to transport functional biomolecules across cellular membranes.

The authors highlight that non-endocytic delivery strategies could become valuable tools for advancing next-generation therapies. However, several challenges remain, including improving delivery specificity, reducing potential immune responses, achieving scalable clinical-grade manufacturing, and ensuring long-term safety.

Looking shead: From delivery challenges to therapeutic opportunities

The review provides a comprehensive perspective on how researchers are moving beyond traditional delivery limitations toward more direct and efficient intracellular transport strategies. By overcoming the cellular membrane barrier, these emerging technologies may help expand the possibilities of biomacromolecule-based therapies and accelerate the development of future precision medicine approaches.

"Delivering functional biomacromolecules into cells remains a major bottleneck for many emerging biomedical therapies, largely due to the low endosomal escape efficiency of conventional endocytosis-dependent pathways. This review highlights how non-endocytic delivery strategies bypass canonical cellular uptake pathways and membrane barriers and provide new opportunities for gene therapy, mRNA therapeutics, protein therapeutics, and cellular engineering," said Dr. Yang Liu, corresponding author of the review.