From intracellular biomolecule delivery to prophylactic cancer immunotherapy: a nine-year research journey

We showed that the PLLA–ZnO/CEA nano vaccine activates dendritic cells, generates balanced antibody and T-cell immunity, remodels the tumor microenvironment, and reduces tumor burden by 65–70% following prophylactic vaccination in mice.
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Springer Vienna
Springer Vienna Springer Vienna

PLLA–ZnO nanowire nano-vaccine orchestrates balanced Th1/Th2 immunity and confers prophylactic antitumor protection

Background Cancer vaccines require both cellular and humoral immunity for optimal therapeutic efficacy. We previously demonstrated that carcinoembryonic antigen (CEA)-coated poly-l-lactic acid-zinc oxide (PLLA-ZnO) nanocomposites induce strong cellular immunity and therapeutic antitumor effects. However, the humoral immune response and prophylactic potential remained unexplored. Methods Female C57BL/6 mice (n = 6/group) were immunized subcutaneously with CEA-coated PLLA-ZnO nanocomposites at two-week intervals. ELISA measured serum antibody responses (IgG1 and IgG2c) at Days 14 and 28 post-immunizations. Flow cytometry assessed IFNγ-producing T cells, and intracellular cytokine staining (ICS) quantified TNF-α, IL-2, and IFN-γ in splenocytes of tumor-bearing mice. Lymphoid cell profiling by multi-parameter flow cytometry characterized immune remodeling in the spleen and tumor microenvironment. Prophylactic efficacy was evaluated in a tumor challenge model using MC38/CEA cells. Results PLLA-ZnO/CEA immunization induced robust and balanced Th1/Th2 humoral immunity, with both IgG1 and IgG2c antibodies reaching high levels after the second immunization (OD₄₅₀ ~ 1.10 and ~ 1.55, respectively). Critically, PLLA-ZnO/CEA elicited significantly higher IgG2c responses than the traditional Alum adjuvant at day 28 (1.55 vs. 1.05 OD₄₅₀, p < 0.001), demonstrating superior Th1 immunity. The IgG1/IgG2c ratio for PLLA-ZnO/CEA (0.72) indicated balanced immunity, contrasting sharply with Alum’s Th2 bias (ratio 1.33). In vitro studies confirmed substantial Type I interferon production and CCR7+ dendritic cell migration. Flow cytometry demonstrated robust IFNγ+ CD4+ and CD8+ T cell responses upon antigen restimulation. In a prophylactic tumor model, PLLA-ZnO/CEA vaccination significantly reduced tumor growth by 65–70% compared to PBS controls (p < 0.001), with sustained protection throughout the observation period. Vaccinated tumor-bearing mice exhibited robust antigen-specific polyfunctional T-cell responses (TNF-α, IL-2, and IFN-γ in both CD4+ and CD8+ splenocytes) and significant expansion of splenic CD8+ T cells and tumor-infiltrating NK cells, indicating active immune remodeling within the tumor microenvironment. Conclusions CEA-coated PLLA-ZnO nanocomposites elicit balanced Th1/Th2 humoral immunity alongside robust cellular responses, providing significant prophylactic protection against tumor growth. These findings, together with characterization of CEA antigen immobilization and dendritic cell uptake, complement our previous demonstration of therapeutic efficacy and establish PLLA-ZnO/CEA as a versatile, mechanistically characterized vaccine platform superior to traditional adjuvants for both preventive and therapeutic cancer immunotherapy. Graphical Abstract

I am pleased to share the newest and most comprehensive article from our continuing research on the PLLA–ZnO nanowire platform for nanovaccines.

FEATURED NEW ARTICLE

“PLLA–ZnO nanowire nano-vaccine orchestrates balanced Th1/Th2 immunity and confers prophylactic antitumor protection."

Cancer Nanotechnology, 2026
https://doi.org/10.1186/s12645-026-00429-3

This study extends our previous therapeutic findings into a prophylactic tumor model while providing a broader mechanistic understanding of the immune response.

The PLLA–ZnO/CEA nanovaccine achieved efficient antigen loading and 96.2% dendritic-cell uptake, induced strong Type I interferon production and increased CCR7 expression, and generated balanced IgG1/IgG2c humoral immunity. It also stimulated antigen-responsive CD4+ and CD8+ T-cell responses involving IFN-γ, TNF-α, and IL-2.

In a prophylactic MC38/CEA mouse model, vaccination reduced tumor burden by 65–70%. It also expanded splenic CD8+ T cells and increased tumor-infiltrating NK cells, demonstrating systemic and tumor-microenvironment remodeling.

This publication represents the latest stage of a research journey that began in 2017:

  1. Intracellular biomolecule delivery (Nanoscale, 2017)

We demonstrated that the three-dimensional organization of ZnO nanowires controls their interaction with cells. Vertical and fan-shaped nanowires efficiently delivered non-covalently associated peptides, while fan-shaped nanowires also enabled intracellular DNA delivery and gene expression through cellular uptake and transient membrane penetration.

https://doi.org/10.1039/C7NR05219G

  1. Translation into intellectual property (Korean patent)

“Delivery of biomacromolecules employing clusters of nanowires”

The patent family covers vertical and radial ZnO nanowire structures, ZnO-binding peptides, and the delivery of proteins, DNA, RNA, drugs, and vaccine antigens.

KR20190027346A / KR102689812B1
https://patents.google.com/patent/KR102689812B1/en

  1. Therapeutic cancer vaccination (Nanoscale, 2019)

We translated the delivery concept into a cancer-vaccine platform, demonstrating dendritic-cell activation, tumor-specific cellular immunity, reduced systemic regulatory T cells, enhanced tumor-infiltrating T cells, and suppression of established tumors.

https://doi.org/10.1039/C8NR08704K

  1. ZnO vaccine mechanisms (Pharmaceutics, 2019)

This review examined ZnO nanocomposites as antigen carriers and immune adjuvants, including nano–bio interactions, immunological mechanisms, and safety considerations.

https://doi.org/10.3390/pharmaceutics11100493

  1. Materials engineering (Advanced Functional Materials, 2021)

This study expanded the materials-science foundation by examining ZnO nano-spicule formation on PLA, structure-dependent wettability, and antibacterial functionality.

https://doi.org/10.1002/adfm.202100844

  1. Tumor-microenvironment modulation (Bioactive Materials, 2024)

Our review examined how multifunctional nanocomposites can overcome immunosuppression and remodel the tumor microenvironment to enhance cancer immunotherapy.

https://doi.org/10.1016/j.bioactmat.2023.08.022

Together, these studies trace the evolution of one scientific concept—from understanding the nanowire–cell interface and delivering biomacromolecules to therapeutic tumor control, tumor-microenvironment modulation, mechanistic immune characterization, and prophylactic antitumor activity.

I am deeply grateful to all the mentors, collaborators, and co-authors who contributed to this research journey.

Follow the Topic

Biomedical Engineering and Bioengineering
Technology and Engineering > Biological and Physical Engineering > Biomedical Engineering and Bioengineering
Biomedical Research
Life Sciences > Health Sciences > Biomedical Research
Nanoengineering
Technology and Engineering > Biological and Physical Engineering > Nanoengineering
Biomaterials-Vaccines
Physical Sciences > Materials Science > Biomaterials > Biomaterials-Vaccines
Biomaterials-Vaccines
Physical Sciences > Chemistry > Materials Chemistry > Biomaterials-Vaccines
Adaptive Immunity
Life Sciences > Biological Sciences > Immunology > Adaptive Immunity