Barriers to advancing nanotechnology to better improve and translate nanomedicines

Near-Infrared Induced miR-34a Delivery from Nanoparticles in Esophageal Cancer Treatment

Current nucleic acid delivery methods have not achieved efficient, non-toxic delivery of miRNAs with tumor-specific selectivity. In this study, a new delivery system based on light-inducible gold-silver-gold, core-shell-shell (CSS) nanoparticles is presented. This system delivers small nucleic acid therapeutics with precise spatiotemporal control, demonstrating the potential for achieving tumor-specific selectivity and efficient delivery of miRNA mimics. The light-inducible particles leverage the photothermal heating of metal nanoparticles due to the local surface plasmonic resonance for controlled chemical cleavage and release of the miRNA mimic payload. The CSS morphology and composition result in a plasmonic resonance within the near-infrared (NIR) region of the light spectrum. Through this method, exogenous miR-34a-5p mimics are effectively delivered to human squamous cell carcinoma TE10 cells, leading to apoptosis induction without adverse effects on untransformed keratinocytes in vitro. The CSS nanoparticle delivery system is tested in vivo in Foxn1nu athymic nude mice with bilateral human esophageal TE10 cancer cells xenografts. These experiments reveal that this CSS nanoparticle conjugates, when systemically administered, followed by 850 nm light emitting diode irradiation at the tumor site, 6 h post-injection, produce a significant and sustained reduction in tumor volume, exceeding 87% in less than 72 h.

Activity and Tissue Distribution of Antisense Oligonucleotide CT102 Encapsulated with Cytidinyl/Cationic Lipid against Hepatocellular Carcinoma

Insulin-like growth factor 1 receptor (IGF1R), a cell surface receptor with tyrosine kinase (TK) activity, has ligands abnormally expressed in acute leukemia, multiple myeloma, breast, prostate, cervical, and nonsmall cell lung cancers, Ewing's sarcoma, and other malignant tumors. IGF1R mediates the malignant proliferation, invasion, and metastasis of tumor cells through a variety of signal transduction pathways, and it is also involved in tumor angiogenesis and tumor cell antiapoptosis. In this study, the neutral cytidinyl lipid DNCA and cystine skeleton cationic lipid CLD from our laboratory could be optimized to encapsulate antisense oligonucleotide (ASO) CT102 to form stable and uniform Mix/CT102 nanoparticles (NPs), which could specifically target tumor cells that highly expressed IGF1R in vivo by intravenous administration. Compared with naked CT102, the lipid complex could promote the uptake and late apoptosis levels of HepG2 and Huh-7 cells, inhibiting cell proliferation efficiently. We also found that Mix/CT102 could enter nucleus in about 2 h, effectively downregulating the mRNA level of IGF1R. The in vivo efficacy experiment demonstrated that in the group that received the optimal dose of Mix/CT102, tumor volume was reduced 8-fold compared with the naked dose group. Meanwhile, in vivo distribution studies showed that the nanoparticles had a predominant accumulation capacity in liver tissue. These results indicated that clinicians can expect the Mix/CT102 nanocomposite to be very effective in reducing the dose and frequency of clinically administered CT102, thereby reducing the side effects of ASOs.

Phagocytic Uptake of Polymeric Particles by Immune Cells under Flow Conditions

Particles injected intravenously are thought to be cleared by macrophages residing in the liver and spleen, but they also encounter circulating immune cells. It remains to be established if the circulating cells can take up particles while flowing and if the uptake capacity is similar under static and flow conditions. Here, we use an in vitro peristaltic pump setup that mimics pulsatile blood flow to determine if immune cells take up particles under constant fluidic flow. We use polystyrene particles of varying sizes as the model of a polymeric particle for these studies. Our results show that the immune cells do phagocytose under flow conditions. We demonstrate that cell lines representing myeloid cells, primary human neutrophils, and monocytes take up submicrometer-sized particles at similar or better rates under flow compared to static conditions. Experiments with whole human blood show that, even under the crowding effects of red blood cells, neutrophils and monocytes take up particles while flowing. Together, these data suggest that circulating immune cells are likely to phagocytose intravenously injected particulates, which has implications for the design of particles to evade or target these cells.

Coating an adenovirus with functionalized gold nanoparticles favors uptake, intracellular trafficking and anti-cancer therapeutic efficacy

Adenoviral (Ad) vectors have proven to be important tools for gene and cell therapy, although some issues still need to be addressed, such as undesired interactions with blood components and off-target sequestration that ultimately hamper efficacy. In the past years, several organic and inorganic materials have been developed to reduce immunogenicity and improve biodistribution of Ad vectors. Here we investigated the influence of the functionalization of 14 nm PEGylated gold nanoparticles (AuNPs) with quaternary ammonium groups and an arginine-glycine-aspartic acid (RGD)-motif on the uptake and biodistribution of Ad vectors. We report the formation of Ad@AuNPs complexes that promote cell attachment and uptake, independently of the presence of the coxsackievirus and adenovirus receptor (CAR) and α_vβ₃ and α_vβ₅ integrins, significantly improving transduction without limiting Ad bioactivity. Besides, the presence of the RGD peptide favors tumor targeting and decreases Ad sequestration in the liver. Additionally, tumor delivery of a coated Ad vector expressing the human sodium iodide symporter (hNIS) by mesenchymal stem cells induces increased accumulation of radioactive iodine (¹³¹I) and tumor volume reduction compared to naked Ad-hNIS, highlighting the promising potential of our coating formulation in cancer gene therapy. STATEMENT OF SIGNIFICANCE: Modification of adenoviral vectors with lipids and polymers can reduce interactions with blood components and increase tumor accumulation; however, increased toxicity and reduced transduction efficiency were indicated. Coating with gold nanoparticles has proven to be a successful strategy for increasing the efficiency of transduction of receptor-defective cell lines. Here we explore the contribution of cell surface receptors on the mechanisms of entry of Ad vectors coated with gold nanoparticles in cell lines with varying degrees of resistance to infection. The enhancement of the anti-tumoral effect shown in this work provides new evidence for the potential of our formulation.

Management of Occupational Risk Prevention of Nanomaterials Manufactured in Construction Sites in the EU

Currently, nanotechnology plays a key role for technological innovation, including the construction sector. An exponential increase is expected in its application, although this has been hampered by the current degree of uncertainty regarding the potential effects of nanomaterials on both human health and the environment. The accidents, illnesses, and disease related to the use of nanoproducts in the construction sector are difficult to identify. For this purpose, this work analyzes in depth the products included in recognized inventories and the safety data sheets of these construction products. Based on this analysis, a review of the recommendations on the use of manufactured nanomaterials at construction sites is performed. Finally, a protocol is proposed with the aim of it serving as a tool for technicians in decision-making management at construction sites related to the use of manufactured nanomaterials. This proposed protocol should be an adaptive and flexible tool while the manufactured nanomaterials-based work continues to be considered as an "emerging risk," despite the expectation that the protocol will be useful for the development of new laws and recommendations for occupational risk prevention management.

Photocontrolled miR-148b nanoparticles cause apoptosis, inflammation and regression of Ras induced epidermal squamous cell carcinomas in mice

Despite evidence that microRNAs (miRNAs) are essential in modulating tumorigenesis, a major challenge in cancer treatment is to achieve tumor-specific selectivity and efficient yet safe delivery of miRNAs in vivo. In this study, we have developed a light-inducible silver nanoparticle nucleic acid delivery system that demonstrates precise spatiotemporal control, high cellular uptake, low cytotoxicity, escape from endosomes and release of functional miRNA into the cytosol. Using this approach, we delivered exogenous miR-148b to induce apoptosis in Ras-expressing keratinocytes and murine squamous cell carcinoma cells while avoiding cytotoxicity in untransformed keratinocytes. When administered to transgenic mice with HRas^G12V-driven skin tumors, a single dose of silver nanoparticle conjugates followed by 415 nm LED irradiation at the tumor site caused a rapid and sustained reduction in tumor volume by 92.8%, recruited T cells to the tumor site, and acted as a potent immunomodulator by polarizing the cytokine balance toward Th1 both locally and systemically. In summary, our results demonstrate that spatiotemporal controlled miR-148b mimic delivery can promote tumor regression efficiently and safely.

Critical evaluation of quantification methods for oligonucleotides formulated in lipid nanoparticles

There is a very large variety in the types of nanoparticulate lipid formulations for oligonucleotides, and remarkably, also a very large heterogeneity in the methods that are used for analyzing oligonucleotide load, encapsulation efficiency and oligonucleotide release. Furthermore, a literature survey showed that the extent to which these procedures are reported in scientific literature varies greatly, with some of them not even reporting any quantification at all. This greatly hampers the reproducibility of nanoparticle preparation between different researchers and between different laboratories, which slows down the clinical translation of such nanomedicines. In this work, a standardized extraction method from liposomes is proposed, in which potential contaminants from the carrier are removed by a simple extraction of the oligonucleotides. These extracts were then analyzed with seven commonly used methods for oligonucleotide quantification, including several absorbance based methods and the most commonly applied dye binding assay. Strikingly, differences in absolute values up to fourfold were found when the same sample was analyzed using different methods which should be taken into consideration when reports using different methods are compared. Furthermore, these results indicate that the most commonly applied method, the dye binding assay, may -without adaptations- not be suitable for short oligonucleotides like siRNAs. The found differences in quantification methods as described here underscore the need for proper documentation of methods to correctly interpret published results, which -with regard to oligonucleotide analysis- is currently lacking in many reports.

Diverse Applications of Nanomedicine

The design and use of materials in the nanoscale size range for addressing medical and health-related issues continues to receive increasing interest. Research in nanomedicine spans a multitude of areas, including drug delivery, vaccine development, antibacterial, diagnosis and imaging tools, wearable devices, implants, high-throughput screening platforms, etc. using biological, nonbiological, biomimetic, or hybrid materials. Many of these developments are starting to be translated into viable clinical products. Here, we provide an overview of recent developments in nanomedicine and highlight the current challenges and upcoming opportunities for the field and translation to the clinic.

Development of nanotoxicology: implications for drug delivery and medical devices

Current nanotoxicology research suffers from suboptimal in vitro models, lack of in vitro–in vivo correlations, variability within in vitro protocols, deficits in both material purity and physicochemical characterization. Reliable nanomaterial toxicity and mechanistic insights are required for health and toxicity risk assessments. Much in vitro toxicological data is inconclusive in designating whether nanomaterials for drug delivery and medical device implants are truly safe. A critique is presented to analyze the interface between toxicology and nanopharmaceuticals. Deficiencies of existing practices in toxicology are reviewed and useful emerging techniques (e.g., lab-on-a-chip, tissue engineering, atomic force microscopy, high-content analysis) are highlighted. Cross-fertilization between disciplines will aid development of biocompatible delivery and implant platforms while improvements are being suggested for better translation of nanotoxicology.