Photothermal
and regenerative therapy

Effective therapies targeting the molecular pathogenesis of liver diseases remain an unmet clinical need. Here, using acute and chronic liver pathology models, we demonstrate a dual therapeutic role for miR-200a encapsulated in poly(lactic acid) (PLA) nanoparticles (NPs) in both treating liver pathology and stimulating regeneration. This rationale is based on miR-200a's central role in regulating oxidative and endoplasmic reticulum (ER) stress, key drivers of liver diseases, enhancing liver regeneration and preventing disease development. Herein, we report the design and therapeutic validation of a nanomedicine platform comprising biocompatible PLA NPs for the hepatic delivery of miR-200a. The resulting PLA@miR-200a NPs (155 ± 39 nm in diameter) demonstrated successful cargo encapsulation and were internalized by hepatocytes in ex vivo liver slice models with minimal cytotoxicity. Pre-complexation of the miR with spermidine facilitated efficient encapsulation within the PLA matrix. Intracellular kinetic studies revealed a degradation-mediated, sustained release profile of the miR payload over 48 h. Crucially, the functional efficacy of this delivery mechanism was validated in vivo, where PLA@miR-200a successfully activated the Keap1/Nrf2 signaling pathway in target hepatocytes, achieving a reliable physiological effect. In a murine model of acute acetaminophen-induced liver injury, a single intraperitoneal administration of PLA@miR-200a profoundly mitigated hepatotoxicity, reduced dystrophic changes, normalized liver enzyme levels, and restored hepatocyte proliferation. Advanced metabolic FLIM imaging in combination with molecular analysis revealed revitalized of cellular biosynthetic activity and antioxidant capacity. Furthermore, in a chronic carbon tetrachloride-induced fibrosis model, the therapy demonstrated potent anti-fibrotic activity, reducing collagen deposition by two stages on the Metavir scale and promoting the resolution of fibrotic septa. In addition, the liver's regenerative capacity and metabolic state were normalized, as evidenced by restored hepatocyte proliferation and FLIM-based metabolic imaging. This work establishes that miR-200a-based nanotherapy has a high potential as a universal, dual-action strategy for not only treating a wide range of liver pathologies but also enhancing the organ's intrinsic regenerative potential, offering significant promise for clinical translation.

Macrophages play a pivotal role in immune regulation and disease progression through their ability to polarize into pro-inflammatory M1 or anti-inflammatory M2 phenotypes. In solid tumors, tumor-associated macrophages (TAMs) are predominantly M2-like and support tumor growth, metastasis, and immune suppression. Reprogramming these macrophages toward the M1 phenotype is a promising therapeutic strategy. STING (Stimulator of Interferon Genes) agonists have emerged as potent agents for inducing M1 polarization and enhancing anti-tumor immunity. However, their clinical use is limited, since it is hard to achieve therapeutic concentration of the agonist within the tumor without causing undesired systemic side effects. In this study, we present internalizable light-responsive carriers of varied sizes - 4.1 μm (Mic) and 0.7 μm (Sub) - for in situ controlled macrophage reprogramming using a light-triggered shift from the M2 to M1 phenotype in melanoma tissues through localized release of a STING agonist (AgST). Near-infrared (NIR) laser pulses enabled effective local heating of Mic and Sub up to 43 and 40 °C at 1035 mW/cm2 with a consequent release about 60 % of the compounds loaded in carriers within 24 h. Both carrier types were efficiently internalized by RAW264.7 macrophages, with an increase of CD86 expression confirming 85-88 % M1-polarized phenotype after irradiation with light. In vivo studies on a murine melanoma model demonstrated significant M1 polarization of TAMs following intratumoral injection of AgST-loaded Mic carriers and subsequent NIR laser irradiation, as evidenced by CD86 expression increased up to 28.3 %. These findings underscore the potential of light-activated carriers for spatiotemporally controlled delivery of immunotherapeutic agents, providing a non-invasive and tunable method for macrophage reprogramming.

Melanoma, a highly malignant and complex form of cancer, has increased in global incidence, with a growing number of new cases annually. Active targeting strategies, such as leveraging the α-melanocyte-stimulating hormone (αMSH) and its interaction with the melanocortin 1 receptor (MC1R) overexpressed in melanoma cells, enhance the concentration of therapeutic agents at tumor sites. For instance, targeted delivery of plasmonic light-sensitive agents and precise hyperthermia management provide an effective, minimally invasive treatment for tumors. In this work, we present a comparative study on targeted photothermal therapy (PTT) using plasmonic gold nanorods (Au NRs) as a robust and safe nanotool to reveal how key treatment parameters affect therapy outcomes. Using an animal model (B16-F10) of melanoma tumors, we compare the targeting abilities of Au NRs modified with two different MC1R agonists, either closely mimicking the αMSH sequence or providing a superior functionalization extent of Au NRs (4.5% (w/w) versus 1.8% (w/w)), revealing 1.6 times better intratumoral localization. Following theoretical and experimental assessments of the heating capabilities of the developed Au NRs under laser irradiation in either the femtosecond (FS)- or nanosecond (NS)- pulsed regime, we perform targeted PTT employing two types of peptide-modified Au NRs and compare therapeutic outcomes revealing the most appropriate PTT conditions. Our investigation reveals greater heat release from Au NRs under irradiation with FS laser, due to the relaxation rates of the electron and phonon temperatures dissipating in the surrounding, which correlates with a more pronounced 17.6 times inhibition of tumor growth when using FS-pulsed regime.

Hyperthermia plays a significant role in cancer treatment by inducing cell damage through temperature elevation, often used alongside other treatment modalities. During hyperthermia therapy, temperature control is crucial. Here, we report on a simple synthesis route of hybrid plasmonic nanodiamonds either completely wrapped with an Au shell (NV@Au) or densely covered with Au NPs (NV@SiO2 @Au). Such integration of nanodiamonds with Au NPs is advantageous both for heating and precise thermometry at nanoscale. After structural and optical investigations, heating abilities of the obtained plasmonic nanodiamonds were thoroughly inspected on glass, in association with living cells, and in tissue slices ex vivo, revealing their effective heat generation under excitation with light using a single excitation source. The developed hybrid plasmonic nanodiamonds were finally applied for local photothermal therapy of melanoma in vivo, demonstrating their efficacy in eradicating cancer cells and monitoring temperature during the process.