Penetrating the cell wall: a review on delivering exogenous materials into plant and fungal cells via micro/nanoinjection.

Intracellular delivery into walled cells is essential for advancing research in plant science, microbiology, and synthetic biology. Conventional enzymatic wall degradation methods are inherently destructive, leading to poor cell survival. Micro/nanoinjection technology, which enables the physical penetration of the cell wall for direct substance introduction, has emerged as a critical solution. This review article presents a systematic overview of this technology. First, we summarize the state-of-the-art in probe design and fabrication. Next, we analyze automation and force-feedback strategies aimed at increasing operational throughput and reproducibility. We then review representative applications across various walled cell types, focusing on the mechanisms of wall penetration. Finally, we discuss technical limitations and propose a roadmap for future development, emphasizing the need for standardized protocols and integrated systems. In this review, first the key advances in probe design and fabrication strategies are summarized. Next, automation and force-feedback strategies aimed at increasing operational throughput and viability are analyzed. Then, the representative applications are discussed on penetrating the cell walls in plant and fungal cells. Finally, current achievements and technical limitations are summarized, and a road-map is proposed for future efforts.