Understanding of endo/lysosomal escape of nanomaterials in biomedical application

Abstract

Emerging therapies rely on the efficient and specific delivery of targeted agents into the cytosol, such as DNA, siRNA and proteins. Nanoparticles showed great potentials in safe delivery and transportation of the targeted cargoes; however, the entrapment in endosomes and degradation by specific enzymes in the lysosome hindered the bioavailability, cytosolic delivery and subsequent therapeutic efficacy. In this case, the development of methods for efficient and specific delivery of targeted therapeutic agents focuses on overcoming the major challenge of endo/lysosomal escape, which relies on the development of safe and efficient nano-delivery systems. A deeper mechanistic understanding in the endo/lysosomal escape will guide the development of more efficient nano-delivery systems. In this review, we summarize various mechanisms by which nanoparticles escape from the endo/lysosome, and showcase the recent progress in dissecting the endo/lysosomal approaches based on nano-delivery systems. Emphasis will lie on the properties of nanoparticles that govern the endo/lysosomal escape pathway as well as the latest promising applications in vaccine delivery and genetic engineering field.

Keywords: biomedical application; endo/lysosomal escape; nanomaterials property.

FIGURE 1

Representative mechanisms for endo/lysosomal escape. Created with BioRender.com.

FIGURE 2

(a) Chemical structure of polyethyleneimine (PEI). (b) Schematic illustration of cationic nanocapping‐mediated charge reversal of phages, facilitating their cellular entry and subsequent endosomal escape. Reproduced with permission. Copyright © 2022, American Association for the Advancement of Science. (c) Surface zeta potential of the nanovaccine before and after PEI modification. (d) Confocal images of DC2.4 cells after co‐incubation with 15.625 μg/ml of PEI coated/uncoated nanovaccine (scale bar = 20 μm). Reproduced with permission. Copyright © 2019, American Chemical Society.

FIGURE 3

(a) Chemical structure and hydrolysis process of the polarity‐switchable polymer. (b) Intracellular co‐localization image of PPE‐A (Green) and lysosome (Red) of A549 cells after incubation with 2.5 μM PPE‐A for different times. Reproduced with permission. Copyright © 2017, American Chemical Society. (c) Transmission electron microscopy (TEM) images of SiO₂ particles (left) and SiO₂ particles coated with carbon nanotubes (CNTs) (right). (d) Live‐cell confocal images of CNTs‐coated silica nanoparticles in HeLa cells. Particle polarization‐induced endo/lysosomal membrane permeabilization, leading to the lysosomal escape of the nanoparticles (Red). Reproduced with permission. Copyright © 2017 Wiley‐VCH.

FIGURE 4

(a) Scheme illustration of topological transformation from nanoparticle to organelle‐like hydrogel architecture in response to lysosomal acidic micro‐environment. The nanoparticles swell and destroy the lysosomal membrane by mechanical force, leading to lysosomal escape. (b)–(c) Bio‐transmission electron microscopy (TEM) images of U87 MG cells treated with 5 μg/mL (b) immutable nanoparticles and (c) expandable nanoparticles. Reproduced with permission. Copyright © 2020 Wiley‐VCH. (d) TEM images of immutable/expandable particles under room temperature and freezing treatment. Ga fragments are indicated by the yellow arrows. (e) Intracellular co‐localization images of expandable particles with lysosomes under room temperature and freezing treatment. Reproduced with permission. Copyright © 2021 Elsevier.

FIGURE 5

(a) Schematic illustration of PBA‐tiggered lysosomal escape of PBA‐modified cylindrical polymer brushes (BCPB‐B). (b) Time‐dependent evolution of the Pearson's correlation coefficients between cylindrical polymer brushes (CPB) and lysosomes in CT26 cells following incubation with 10 μg/ml of BCPB‐B and BCPB (CPB without phenylboronic acid [PBA] modification). Reproduced with permission. Copyright © 2021 American Chemical Society. (c) Schematic illustration of a CTSB‐sensitive system facilitating cell‐specific intracellular antibody delivery via a selective endosomal escape pathway. (d) Time‐dependent evolution of the co‐localization coefficients between antibodies and lysosomes in CT26 cells, with or without CTSB inhibitor treatment. Reproduced with permission. Copyright © 2024 Wiley‐VCH.

FIGURE 6

(a) Intracellular co‐localization image of OVA (Green) and lysosome (Red) in DC2.4 cells after incubation with 10 μg/ml n(OVA)C7A nanovaccine and control groups for 24 h (scale bar = 40 μm). (b) Flow cytometry analysis of H‐2K^b/SIINFEKL⁺cell population in bone marrow‐derived dendritic cells (BMDCs) after incubation with nanovaccines. (c) Percentage of CD8⁺ T cells activated in lymph nodes after vaccine treatment. Reproduced with permission. Copyrights © 2024 Elsevier. (d) Schematic illustration of cGAMP cytosolic delivery by STING‐NPs via pH‐responsive endosomal escape process. (e) Treatment scheme for mice treated intravenously with vaccine formulations and intraperitoneally with immune checkpoint blockade (ICB). (f) Representative images of tumors 8 days after initial treatment. (g) Tumor growth curves following intravenous injection of the formulations. Reproduced with permission. Copyright © 2019 Springer Nature.

FIGURE 7

Preparation process of NP/pZNF580/RBCs and their gene delivery by crossing extracellular and intracellular barriers. Reproduced with permission. Copyright © 2018 Royal Society of Chemistry.