Quantification of Surface GalNAc Ligands Decorating Nanostructured Lipid Carriers by UPLC-ELSD

Bimodal Treatment of Hepatocellular Carcinoma by Targeted Minimally Interventional Photodynamic/Chemotherapy Using Glyco-Covalent-Organic Frameworks-Guided Porphyrin/Sorafenib

Very limited treatment options are available to fight hepatocellular carcinoma (HCC), a serious global health concern with high morbidity and mortality. The integration of multiple therapies into one nanoplatform to exert synergistic therapeutic effects offers advantages over monotherapies. Here, we describe the construction of the nanoplatform Sor@GR-COF-366 for synergistic chemotherapy and photodynamic therapy (PDT) for HCC using a porphyrin-based covalent organic framework (COF-366) coated with N-acetyl-galactosamine (GalNAc) and rhodamine B (RhB), and loaded with the first-line agent, Sorafenib (Sor). The nanoplatform is targeted towards ASGPR-overexpressed HCC cells and liver tissues by GalNAc and observed by real-time imaging of RhB in vitro and in vivo. The nanoplatform Sor@GR-COF-366 exerts an enhanced synergistic tumor suppression effect in a subcutaneous HCC mouse model with a tumor inhibition rate (TGI) of 97% while significantly prolonging survival at very low toxicity. The potent synergistic therapeutic outcome is confirmed in an orthotopic mouse model of HCC with the TGI of 98% with a minimally invasive interventional PDT (IPDT). Sor@GR-COF-366 is a promising candidate to be combined with chemo-IPDT for the treatment of HCC. STATEMENT OF SIGNIFICANCE: This work describes the construction of covalent-organic frameworks (COFs) modified with glyco-moieties to serve as hepato-targeted multitherapy delivery systems. They combine minimally invasive interventional photodynamic therapy (IPDT) triggered synergism with chemotherapy treatment for hepatocellular carcinoma (HCC). With the aid of minimally invasive intervention, PDT can elicit potent anti-cancer activity for deep solid tumors. This platform shows strong therapeutic outcomes in both subcutaneous and orthotopic mouse models, which can significantly prolong survival. This work showed an effective combination of a biomedical nano-formulation with the clinical operational means in cancer treatment, which is greatly promising in clinical translation.

Quantification of Available Ligand Density on the Surface of Targeted Liposomal Nanomedicines at the Single-Particle Level

Active targeting has been hailed as one of the most promising strategies to further enhance the therapeutic efficacy of liposomal nanomedicines. Owing to the critical role of ligand density in mediating cellular uptake and the intrinsic heterogeneity of liposomal formulations, precise quantification of the surface ligand density on a single-particle basis is of fundamental importance. In this work, we report a method to simultaneously measure the particle size and the number of ligands on the same liposomal nanoparticles by nanoflow cytometry. Then the ligand density for each individual liposome can be determined. With an analysis rate up to 10 000 particles per minute, a statistically representative distribution of ligand density could be determined in minutes. By utilizing fluorescently labeled recombinant receptors as the detection probe against the conjugated ligands, only those available for cell targeting can be exclusively detected. The influence of ligand input, conjugation strategy, and the polyethylene glycol spacer length on the available ligand density of folate-modified liposomes was investigated. The correlation between the available ligand density and cell targeting capability was assessed in a quantitative perspective for liposomes modified with three different targeting moieties. The optimal ligand density was determined to be 0.5-2.0, 0.7, and 0.2 ligand per 100 nm² for folate-, transferrin-, and HER2-antibody-conjugated liposomes, respectively. These optimal values agreed well with the spike density of the natural counterparts, viruses. The as-developed approach is generally applicable to a wide range of active-targeting nanocarriers.

Development, formulation, and cellular mechanism of a lipophilic copper chelator for the treatment of Wilson's disease

Copper homeostasis is finely regulated in human to avoid any detrimental impact of free intracellular copper ions. Upon copper accumulation, biliary excretion is triggered in liver thanks to trafficking of the ATP7B copper transporter to bile canaliculi. However, in Wilson's disease this protein is mutated leading to copper accumulation. Current therapy uses Cu chelators acting extracellularly and requiring a life-long treatment with side effects. Herein, a new Cu(I) pro-chelator was encapsulated in long-term stable nanostructured lipid carriers. Cellular assays revealed that the pro-chelator protects hepatocytes against Cu-induced cell death. Besides, the cellular stresses induced by moderate copper concentrations, including protein unfolding, are counteracted by the pro-chelator. These data showed the pro-chelator efficiency to deliver intracellularly an active chelator that copes with copper stress and surpasses current and under development chelators. Although its biological activity is more mitigated, the pro-chelator nanolipid formulation led to promising results. This innovative approach is of outmost importance in the quest of better treatments for Wilson's disease.

Lectin recognition and hepatocyte endocytosis of GalNAc-decorated nanostructured lipid carriers

Liver is the main organ for metabolism but is also subject to various pathologies, from viral, genetic, cancer or metabolic origin. There is thus a crucial need to develop efficient liver-targeted drug delivery strategies. Asialoglycoprotein receptor (ASGPR) is a C-type lectin expressed in the hepatocyte plasma membrane that efficiently endocytoses glycoproteins exposing galactose (Gal) or N-acetylgalactosamine (GalNAc). Its targeting has been successfully used to drive the uptake of small molecules decorated with three or four GalNAc, thanks to an optimisation of their spatial arrangement. Herein, we assessed the biological properties of highly stable nanostructured lipid carriers (NLC) made of FDA-approved ingredients and formulated with increasing amounts of GalNAc. Cellular studies showed that a high density of GalNAc was required to favour hepatocyte internalisation via the ASGPR pathway. Interaction studies using surface plasmon resonance and the macrophage galactose-lectin as GalNAc-recognising lectin confirmed the need of high GalNAc density for specific recognition of these NLC. This work is the first step for the development of efficient nanocarriers for prolonged liver delivery of active compounds.

Editorial of Special Issue "Surface-Functionalized Nanoparticles as Drug Carriers"

Safe and effective delivery of therapeutics at the target site is the key to successful therapy. Nanocarriers can offer significant advantages over conventional dosage forms. Over the decades, nanoparticles have been extensively used to increase bioavailability, improve solubility and stability, reduce toxicities, and facilitate the controlled release of therapeutics. Further, nanoparticles have often been surface-functionalized with a variety of ligands to enhance circulation half-life and increase target-specificity. Although nanotechnology has shown significant therapeutic benefits for multiple biomedical applications, limited nanoparticle-based formulations have progressed to clinical trials, and only a few have reached the pharmaceutical market. This editorial is an introduction to the special issue entitled Surface-Functionalized Nanoparticles as Drug Carriers. We outline the scope of the special issue, summarize the results and conclusions of the nine articles published in this issue, and provide perspective on the application of surface-functionalized nanoparticles in the drug delivery field.