Cited by 35Nanoparticle-Based Drug DeliveryNanoplatforms for cancer theranosticsRNA Interference and Gene Delivery

The DOI matches its Crossref record; 135 of the 135 references it cites were found in a registry or an index; 10 of the 191 sources its claims cite were checked for support.

Overcoming tumor microenvironment barriers: transformable and bioinspired nanomedicine strategies for deep tumor penetration

Open access

Abstract

Solid tumors pose a spatial “delivery-at-depth” bottleneck: therapeutics that reach tumors often remain sequestered near vessels and fail to distribute uniformly into tumor cores. This limitation arises from heterogeneous perfusion, elevated interstitial fluid pressure, and dense extracellular matrix, which together restrict convection–diffusion balance and amplify binding-site barriers. We organize transformable and bioinspired nanomedicines using a barrier-centric lens and summarize five strategy families to deepen and homogenize intratumoral transport: (i) stimuli-responsive size/charge switching, (ii) microenvironment remodeling to restore perfusion and decompress stroma, (iii) ligand-guided transcytosis and CendR pathway engagement, (iv) cell-based and biomimetic vectors leveraging homing and immune evasion, and (v) multistage designs that sequence priming, switching, and payload activation. We compare representative systems by trigger specificity, activation timing, affinity tuning, and corona susceptibility, and highlight recurring failure modes including stimulus heterogeneity, premature/off-target activation, and escalating chemistry–manufacturing–controls burdens with added components. We conclude with translational priorities: couple barrier priming with a single well-characterized switching event, favor moderated or activatable affinity to avoid perivascular trapping, and validate spatial gains using standardized intratumoral distribution metrics linked to therapeutic endpoints. Graphical Abstract

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This review maps transformable and bioinspired nanomedicines onto five barrier-centric strategy families for deep tumor penetration and compares their triggers, timing, affinity, and corona susceptibility. It argues that deep homogeneous delivery requires coordinated vascular access, stromal resistance reduction, and on-site activation, with translational priority on barrier priming plus a single well-characterized switch and standardized spatial metrics.

Key findings

  • Five strategy families are synthesized: stimuli-responsive size/charge switching, microenvironment remodeling, ligand-guided transcytosis/CendR engagement, cell-based and biomimetic vectors, and multistage designs that sequence priming, switching, and payload activation.
  • Representative transformable systems report large switches: HAase-responsive Te/QAm polycarbonate masks a cationic core (ζ ~ −27 mV, 160 nm), shrinks to ~130 nm and reverses positive, enabling uniform penetration through 3.6 mm DMMA xenografts with ~87% tumor inhibition; Met@BF shifts −16.6 to +18.5 mV at pH 6.0, penetrates melanoma spheroids ~60 µm, and gives ~87% tumor inhibition.
  • Barrier-remodeling and bioinspired examples include collagenase@CMSNs with detectable penetration depth 1200 μm and 86% tumor inhibition, ENP5 fusiform CaP with a 12.2× penetration enhancement factor, and neutrophil “Trojanbots” with ~50% BBB crossing, ~416 μm spheroid propulsion, and median survival 45 days vs PBS 18 days.
  • Recurring failure modes are stimulus heterogeneity, premature/off-target activation, and escalating chemistry–manufacturing–controls burden; clinical translation remains sparse and many trials do not report standardized intratumoral transport metrics.

Methods

  • Review article, not a primary study; it organizes transformable and bioinspired nanomedicines into five penetration-enabling strategy families (S1–S5) using a barrier-centric framework.
  • Compares representative systems by trigger specificity, activation timing, affinity tuning, and corona susceptibility, and consolidates penetration/efficacy readouts in Tables 1–6 with explicit comparator arms where reported.
  • Discusses preclinical models (spheroids, xenografts, patient-derived organoids, tumor-on-a-chip) and provides a clinical translation snapshot compiled from prior review sources.

Limitations

  • Stated: most penetration claims are established in subcutaneous or orthotopic xenografts and simple 3D spheroids, which only partially recapitulate patient-level heterogeneity; spheroid penetration of 50–200 μm and rodent millimeter-scale readouts are relative performance metrics, not direct predictors of human penetration.
  • Stated: stimulus heterogeneity, premature/incomplete/misplaced activation, insufficient long-term biosafety study of residual metallic or polymeric fragments, and CMC/manufacturability burdens for multi-component bioinspired constructs.
  • Evident: as a review, it generates no new experimental data; cross-study comparisons are constrained by heterogeneous models, imaging pipelines, and comparator arms, and many clinical trials do not report standardized intratumoral transport metrics.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1186/s12951-026-04028-7

Cites

135 of 135 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Figures

Fig. 1 Modular, barrier-centric map of strategies for deep tumor penetration. The outer ring summarizes five strategy families (S1–S5). The middle ring indicates the dominant barrier level targeted (vasculature, ECM/IFP, interstitium, and cellular barriers). Inner icons denote representative triggers (e.g., pH, enzymes, redox, hypoxia, shear) and transformation outputs (e.g., size/charge/ligand exposure) used across the five families
Fig. 1 Modular, barrier-centric map of strategies for deep tumor penetration. The outer ring summarizes five strategy families (S1–S5). The middle ring indicates the dominant barrier level targeted (vasculature, ECM/IFP, interstitium, and cellular barriers). Inner icons denote representative triggers (e.g., pH, enzymes, redox, hypoxia, shear) and transformation outputs (e.g., size/charge/ligand exposure) used across the five familiesCC BY · PubMed Central
Fig. 2 Size switchable Au-Fe2C nanocapsules enable cascade delivery in the tumor microenvironment. Acidic or mild thermal cues degrade the shell and release ultrasmall Au-Fe2C cores for deep penetration, coupled with glutathione depletion, Fenton chemistry, and sorafenib-mediated GPX4 inhibition to drive ferroptosis. Adapted with permission from Wang, J.; Fang, Z.; Zhao, C.; et al., Advanced Materials 36 (2024) 2,307,006, 10.1002/adma.202307006. © 2023 Wiley–VCH GmbH. Permission under Wiley License No. 6121350053588. Changes were made. [21]
Fig. 2 Size switchable Au-Fe2C nanocapsules enable cascade delivery in the tumor microenvironment. Acidic or mild thermal cues degrade the shell and release ultrasmall Au-Fe2C cores for deep penetration, coupled with glutathione depletion, Fenton chemistry, and sorafenib-mediated GPX4 inhibition to drive ferroptosis. Adapted with permission from Wang, J.; Fang, Z.; Zhao, C.; et al., Advanced Materials 36 (2024) 2,307,006, 10.1002/adma.202307006. © 2023 Wiley–VCH GmbH. Permission under Wiley License No. 6121350053588. Changes were made. [21]CC BY · PubMed Central
Fig. 3 Hypoxia-associated tumor-associated macrophage-derived adrenomedullin (ADM) destabilizes endothelial adherens junctions via the calcitonin receptor-like receptor (CRLR), leading to vascular hyperpermeability. Blocking ADM restores vessel integrity, enhances intratumoral drug delivery, and improves antitumor efficacy. Adapted from Wang, W., et al., Cancer Cell 42 (2024) 815–832, 10.1016/j.ccell.2024.03.013. Licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Changes were made [48]
Fig. 3 Hypoxia-associated tumor-associated macrophage-derived adrenomedullin (ADM) destabilizes endothelial adherens junctions via the calcitonin receptor-like receptor (CRLR), leading to vascular hyperpermeability. Blocking ADM restores vessel integrity, enhances intratumoral drug delivery, and improves antitumor efficacy. Adapted from Wang, W., et al., Cancer Cell 42 (2024) 815–832, 10.1016/j.ccell.2024.03.013. Licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Changes were made [48]CC BY · PubMed Central
Fig. 4 Neutrophil “Trojanbot” ferries catalase-powered nanobots across the blood-brain barrier via chemotaxis, and upon release in the tumor microenvironment the nanobots self-propel along hydrogen peroxide gradients to achieve deep tumor penetration and enhanced doxorubicin delivery in glioblastoma. Reproduced from Gao, Y., et al., Nature Communications 16 (2025) 5263, 10.1038/s41467-025-60422-z. © The Author(s) 2025. Licensed under CC BY-NC-ND 4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0/). No changes were made [64]
Fig. 4 Neutrophil “Trojanbot” ferries catalase-powered nanobots across the blood-brain barrier via chemotaxis, and upon release in the tumor microenvironment the nanobots self-propel along hydrogen peroxide gradients to achieve deep tumor penetration and enhanced doxorubicin delivery in glioblastoma. Reproduced from Gao, Y., et al., Nature Communications 16 (2025) 5263, 10.1038/s41467-025-60422-z. © The Author(s) 2025. Licensed under CC BY-NC-ND 4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0/). No changes were made [64]CC BY · PubMed Central
Fig. 5 Schematic of ligand- and enzyme-triggered penetration. The R6-AANCK-CBT precursor is cleaved by legumain, exposing reactive groups that drive intracellular assembly into nanostructures and enhance transport across tissue barriers and intracellular delivery. Adapted with permission from Ghaemi, B.; Tanwar, S.; Singh, A.; et al., ACS Applied Materials & Interfaces 16 (2024) 11,159–11,171, 10.1021/acsami.3c14908. © 2024 American Chemical Society. Permission under RightsLink License No. 6123170315940. Changes were made. [80]
Fig. 5 Schematic of ligand- and enzyme-triggered penetration. The R6-AANCK-CBT precursor is cleaved by legumain, exposing reactive groups that drive intracellular assembly into nanostructures and enhance transport across tissue barriers and intracellular delivery. Adapted with permission from Ghaemi, B.; Tanwar, S.; Singh, A.; et al., ACS Applied Materials & Interfaces 16 (2024) 11,159–11,171, 10.1021/acsami.3c14908. © 2024 American Chemical Society. Permission under RightsLink License No. 6123170315940. Changes were made. [80]CC BY · PubMed Central

Verification

Claims the paper makes

86 No full text of the sources · 81 Not checked yet · 54 Own interpretation · 7 Partly supported · 5 No basis given · 2 Couldn’t confirm · 1 Own result · accuracy not yet measured

Verify all 85 references — free account

Show all 95 claims

  • It may state two separate claims as one. 130
  • The quote only partly states this claim. 1
  • Probably not a substantial claim. 13
141 of 141
  • The paper relies on this without support.

    Intratumoral penetration remains the most critical and limiting factor for effective delivery to solid tumors, particularly for nanoparticle-based systems.

    “Among these, intratumoral penetration remains the most critical and limiting factor, particularly for nanoparticle-based systems.”
  • The paper relies on this without support.

    Most penetration claims have been established in subcutaneous or orthotopic xenografts and relatively simple 3D spheroids, which only partially recapitulate patient-level heterogeneity in perfusion, stromal architecture and immune contexture.

    “To date, most penetration claims have been established in subcutaneous or orthotopic xenografts and relatively simple 3D spheroids, which only partially recapitulate patient-level heterogeneity in perfusion, stromal architecture and immune contexture.”
  • The paper relies on this without support.

    MMP-2/9 expression is highly context dependent across tumor types, between stromal and malignant compartments, and over the course of therapy.

    “Likewise, MMP-2/9 expression is highly context dependent across tumor types (e.g. pancreatic versus brain or prostate cancer), between stromal and malignant compartments, and over the course of therapy;”
  • The paper relies on this without support.

    The long-term biosafety of residual metallic or polymeric fragments remains insufficiently studied.

    “Furthermore, the long-term biosafety of residual metallic or polymeric fragments remains insufficiently studied, and scaling production to GMP standards requires modular and reproducible chemistries.”
  • The paper relies on this without support.

    Tumor vessels are structurally and functionally abnormal, with irregular branching, poor pericyte coverage and leaky junctions that jointly increase interstitial fluid pressure and impair convective transport.

    “Tumor vessels are structurally and functionally abnormal, with irregular branching, poor pericyte coverage and leaky junctions that jointly increase interstitial fluid pressure and impair convective transport.”
  • The paper relies on this without support.

    The tumor microenvironment combines poorly perfused and tortuous vessels, elevated IFP, a collagen-rich matrix, and immunosuppressive cells, which together distort drug gradients and create protected core regions that resist therapy.

    “The tumor microenvironment combines poorly perfused and tortuous vessels, elevated IFP, a collagen-rich matrix, and immunosuppressive cells, which together distort drug gradients and create protected core regions that resist therapy.”
  • The paper relies on this without support.

    Intratumoral transport is restricted by abnormal vasculature, elevated interstitial fluid pressure, and a dense extracellular matrix.

    “Intratumoral transport is restricted by abnormal vasculature, elevated IFP, and a dense ECM.”
  • The paper relies on this without support.

    Cell-based and biomimetic vectors leverage innate homing, transendothelial migration, chemotaxis, and immune evasion to improve accumulation, penetration, and on-site release.

    “Cell-based and biomimetic vectors leverage innate homing, transendothelial migration, chemotaxis, and immune evasion to improve accumulation, penetration, and on-site release.”
  • The paper relies on this without support.

    Agents such as hyaluronidase, PEGylated recombinant hyaluronidase (PEGPH20), losartan and TGF-β or LOX inhibitors deplete hyaluronan, relax collagen networks and decompress vessels, thereby improving nanomedicine accumulation in desmoplastic tumors.

    “In the first category, agents such as hyaluronidase, PEGylated recombinant hyaluronidase (PEGPH20), losartan and TGF-β or LOX inhibitors have been shown to deplete hyaluronan, relax collagen networks and decompress vessels, thereby improving nanomedicine accumulation in desmoplastic tumors.”
  • The paper relies on this without support.

    Photosynthetic Chlorella loaded with indocyanine green generates oxygen under 660 nm irradiation and splits interstitial water, which lowers interstitial fluid pressure, improves perfusion, and deepens doxorubicin penetration in vivo.

    “Photosynthetic Chlorella loaded with indocyanine green generates oxygen under 660 nm irradiation and splits interstitial water, which lowers interstitial fluid pressure, improves perfusion, and deepens doxorubicin penetration in vivo.”
  • The paper relies on this without support.

    Cell-penetrating peptides act as bioinspired modules that strengthen membrane engagement, endocytic entry, and endosomal escape, and can also support adsorptive-mediated transcytosis at endothelium.

    “Cell-penetrating peptides (CPP) act as bioinspired modules that strengthen membrane engagement, endocytic entry, and endosomal escape, and can also support adsorptive-mediated transcytosis at endothelium.”
  • The paper relies on this without support.

    Peptide synthesis and conjugation impose sequence-specific quality control requirements, while protease susceptibility, serum binding and binding-site barriers can restrict tissue spread and distort biodistribution profiles.

    “In addition, peptide synthesis and conjugation impose sequence-specific quality control requirements, while protease susceptibility, serum binding and binding-site barriers can restrict tissue spread and distort biodistribution profiles.”
12 of 12

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

8 of 8

Citations

Cites

Show all 135 references

Cited by

Sorted by citations

See all 35

Metadata

Authors
Sheng, J., Yuan, W., Zhang, M., Chen, Z., Qi, Y., Zhao, Y., & Zhang, S.
Affiliations
  • Dalian Minzu University (CN)
  • The University of Sydney (AU)
Corresponding author
  • Zhao, Yinan
  • Zhang, Shubiao
Venue
Journal of Nanobiotechnology
Published
2026-01-30
Volume
24
Issue
1
ISSN
1477-3155 (ISSN-L)
OpenAlex
W7126181746
Cited by
35
References
135
Citations by year
2026: 35
FWCI
12.55
Type
journal article
Language
en
Open access
Locations
  • Journal of Nanobiotechnology (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (publishedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
Funders
  • Science and Technology Innovation Fund of Dalian (2023JJ11CG007, 2022JJ12SN046)
  • the Key Research and Development Project of Liaoning Province (2023JH2/101800011)
  • National Natural Science Foundation of China (U23A20488)
Topics
  • Physical Sciences › Materials Science › Biomaterials › Nanoparticle-Based Drug Delivery
  • Physical Sciences › Engineering › Biomedical Engineering › Nanoplatforms for cancer theranostics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › RNA Interference and Gene Delivery
Keywords
deep tumor penetration, intratumoral drug distribution, stimuli-responsive nanomedicine, microenvironment remodeling, interstitial fluid pressure, extracellular matrix, transcytosis, biomimetic nanocarriers, solid tumors
MeSH terms
Animals, Humans, Neoplasms, Drug Delivery Systems, Biomimetics, Nanomedicine, Tumor Microenvironment

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

A language model drew the claims from the paper on 2026-11-10, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).

A second model labelled each claim on 2026-11-10 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).

Cited sources are checked with a language model’s help (gpt-6-sol).

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review