Comparative Analysis of Nucleic Acid-Binding Polymers as Potential Anti-Inflammatory Nanocarriers.

Conventionally, nanocarriers are used to regulate the controlled release of therapeutic payloads. Increasingly, they can also be designed to have an intrinsic therapeutic effect. For example, a positively charged nanocarrier can bind damage-associated molecular patterns, inhibiting toll-like receptor (TLR) pathway activation and thus modulating inflammation. These nucleic acid-binding nanomaterials (NABNs), which scavenge pro-inflammatory stimuli, exist in diverse forms, ranging from soluble polymers to nanoparticles and 2D nanosheets. Unlike conventional drugs that primarily address inflammation symptoms, these NABPs target the upstream inflammation initiation pathway by removing the agonists responsible for inflammation. Many NABNs have demonstrated effectiveness in murine models of inflammatory diseases. However, these scavengers have not been systematically studied and compared within a single setting. Herein, we screen a subset of the most potent NABNs to define their relative efficiency in scavenging cell-free nucleic acids and inhibiting various TLR pathways. This study helps interpret existing in vivo results and provides insights into the future design of anti-inflammatory nanocarriers.

Targeting Proinflammatory Molecules Using Multifunctional MnO Nanoparticles to Inhibit Breast Cancer Recurrence and Metastasis.

Photothermal therapy (PTT) is an effective treatment modality that is highly selective for tumor suppression and is a hopeful alternative to traditional cancer therapy. However, PTT-induced inflammatory responses may result in undesirable side effects including increased risks of tumor recurrence and metastasis. Here we developed multifunctional MnO nanoparticles as scavengers of proinflammatory molecules to alleviate the PTT-induced inflammatory response. The MnO nanoparticles improve the PTT therapy by (1) binding and scavenging proinflammatory molecules to inhibit the proinflammatory molecule-induced Toll-like receptors (TLR) activation and nuclear factor kappa B (NF-κB) signaling; (2) inhibiting activated macrophage-induced macrophage recruitment; and (3) inhibiting tumor cell migration and invasion. In vivo experimental results showed that further treatment with MnO nanoparticles after laser therapy not only inhibited the PTT-induced inflammatory response and primary tumor recurrence but also significantly reduced tumor metastasis due to the scavenging activity. These findings suggest that MnO nanoparticles hold the potential for mitigating the therapy-induced severe inflammatory response and inhibiting tumor recurrence and metastasis.

Therapeutic Nanocarriers Inhibit Chemotherapy-Induced Breast Cancer Metastasis.

Chemotherapy, although effective against primary tumors, may promote metastasis by causing the release of proinflammatory factors from damaged cells. Here, polymeric nanoparticles that deliver chemotherapeutics and scavenge proinflammatory factors simultaneously to inhibit chemotherapy-induced breast cancer metastasis are developed. The cationic nanoparticles can adsorb cell-free nucleic acids (cfNAs) based on charge-charge interaction, which downregulates the expression of Toll-like receptors and then reduces the secretion of inflammatory cytokines. Through in vitro structural optimization, cationic polyamidoamine (PAMAM) dendrimers modified with drug-binding dodecyl groups and diethylethanolamine surface groups (PAMAM-G3-C125 -DEEA20 ) exhibit the most desirable combination of nanoparticle size (≈140 nm), drug loading, cytotoxicity, cfNA binding, and anti-inflammatory activity. In the mouse models of breast cancer metastasis, paclitaxel-loaded nanoparticles reduce serum levels of cfNAs and inflammatory cytokines compared with paclitaxel treatment alone and inhibit both primary tumor growth and tumor metastasis. Additionally, no significant side effects are detected in the serum or major organs. These results provide a strategy to deliver chemotherapeutics to primary tumors while reducing the prometastatic effects of chemotherapy.

Mining, expression, and phylogenetic analysis of volatile terpenoid biosynthesis-related genes in different tissues of ten Elsholtzia species based on transcriptomic analysis.

We sequenced the leaf and inflorescence transcriptomes of 10 Elsholtzia species to mine genes related to the volatile terpenoid metabolic pathway. A total of 184.68 GB data and 1,231,162,678 clean reads were obtained from 20 Elsholtzia samples, and 333,848 unigenes with an average length of at least 1440 bp were obtained by Trinity assembly. KEGG pathway analysis showed that there were three pathways related to volatile terpene metabolism: terpenoid backbone biosynthesis (No. ko00900), monoterpenoid biosynthesis (No. ko00902), and sesquiterpenoid and triterpenoid biosynthesis (No. ko00909), with 437, 125, and 121 related unigenes, respectively. The essential oil content and composition in 20 Elsholtzia samples were determined by gas chromatography-mass spectrometry. The results showed that there were obvious interspecific differences among the 10 Elsholtzia species, but there were no significant differences between the different tissues among species. The expression levels of seven candidate genes involved in volatile terpenoid biosynthesis in Elsholtzia were further analyzed by quantitative real-time PCR. The results showed that HMGS had the highest expression among all genes, followed by GGPS4. In addition, there was not a significant correlation between the seven genes and the components with high essential oil contents. Combined with the essential oil components detected in this study, the possible biosynthetic pathway of the characteristic components in Elsholtzia plants was speculated to be a metabolic pathway with geraniol as the starting point and elsholtzione as the end product. Phylogenetic analysis was conducted using the nucleotide sequences of the geranyl diphosphate synthase candidate genes, and the results showed that genes related to the volatile terpenoid biosynthetic pathway may be more suitable gene fragments for resolving the Elsholtzia phylogeny.

Design of therapeutic biomaterials to control inflammation.

Inflammation plays an important role in the response to danger signals arising from damage to our body and in restoring homeostasis. Dysregulated inflammatory responses occur in many diseases, including cancer, sepsis and autoimmunity. The efficacy of anti-inflammatory drugs, developed for the treatment of dysregulated inflammation, can be potentiated using biomaterials, by improving the bioavailability of drugs and by reducing side effects. In this Review, we first outline key elements and stages of the inflammatory environment and then discuss the design of biomaterials for different anti-inflammatory therapeutic strategies. Biomaterials can be engineered to scavenge danger signals, such as reactive oxygen and nitrogen species and cell-free DNA, in the early stages of inflammation. Materials can also be designed to prevent adhesive interactions of leukocytes and endothelial cells that initiate inflammatory responses. Furthermore, nanoscale platforms can deliver anti-inflammatory agents to inflammation sites. We conclude by discussing the challenges and opportunities for biomaterial innovations in addressing inflammation.

DAMPs/PAMPs induce monocytic TLR activation and tolerance in COVID-19 patients; nucleic acid binding scavengers can counteract such TLR agonists.

Millions of COVID-19 patients have succumbed to respiratory and systemic inflammation. Hyperstimulation of toll-like receptor (TLR) signaling is a key driver of immunopathology following infection by viruses. We found that severely ill COVID-19 patients in the Intensive Care Unit (ICU) display hallmarks of such hyper-stimulation with abundant agonists of nucleic acid-sensing TLRs present in their blood and lungs. These nucleic acid-containing Damage and Pathogen Associated Molecular Patterns (DAMPs/PAMPs) can be depleted using nucleic acid-binding microfibers to limit the patient samples' ability to hyperactivate such innate immune receptors. Single-cell RNA-sequencing revealed that CD16+ monocytes from deceased but not recovered ICU patients exhibit a TLR-tolerant phenotype and a deficient anti-viral response after ex vivo TLR stimulation. Plasma proteomics confirmed such myeloid hyperactivation and revealed DAMP/PAMP carrier consumption in deceased patients. Treatment of these COVID-19 patient samples with MnO nanoparticles effectively neutralizes TLR activation by the abundant nucleic acid-containing DAMPs/PAMPs present in their lungs and blood. Finally, MnO nanoscavenger treatment limits the ability of DAMPs/PAMPs to induce TLR tolerance in monocytes. Thus, treatment with microfiber- or nanoparticle-based DAMP/PAMP scavengers may prove useful for limiting SARS-CoV-2 induced hyperinflammation, preventing monocytic TLR tolerance, and improving outcomes in severely ill COVID-19 patients.

A Mononuclear Iron(II) Spin-Crossover Molecule Decorated by Photochromic Azobenzene Group.

Aiming at constructing photoresponsive spin crossover (SCO) behavior, herein we designed a new ligand Abtz (Abtz = (E)-N-(4-((E)-phenyldiazenyl)phenyl)-1-(thiazol-4-yl)methanimine) which was decorated by a photochromic azobenzene group. Based on this photochromic ligand, a mononuclear Fe(II) SCO molecule [Fe(Abtz)3](BF4)2·(EAC)2 (1, EAC = ethyl acetate) was successfully synthesized and showed a complete one-step SCO behavior. Under continuous UV light and blue-light exposure, the cis-trans photoisomerization of both ligand Abtz and compound 1 in the liquid phase was confirmed through UV-Vis spectra. Moreover, the 1H-NMR spectra of Abtz reveal a trans-cis conversion ratio of 37%. Although the UV-Vis spectra reveal the photochromic behavior for 1 in the solution phase, the SCO behavior in the liquid state is absent according to the variable-temperature Evans method, suggesting the possible decomposition. Moreover, in the solid state, the cis-trans photoisomerization of both Abtz and 1 was not observed, due to the steric hindrance.

A Cationic Metal-Organic Framework to Scavenge Cell-Free DNA for Severe Sepsis Management.

Circulating cell-free DNA (cfDNA) released by damaged cells causes inflammation and has been associated with the progression of sepsis. One proposed strategy to treat sepsis is to scavenge this inflammatory circulating cfDNA. Here, we develop a cfDNA-scavenging nanoparticle (NP) that consists of cationic polyethylenimine (PEI) of different molecular weight grafted to zeolitic imidazolate framework-8 (PEI-g-ZIF) in a simple one-pot process. PEI-g-ZIF NPs fabricated using PEI 1800 and PEI 25k but not PEI 600 suppressed cfDNA-induced TLR activation and subsequent nuclear factor kappa B pathway activity. PEI 1800-g-ZIF NPs showed greater inhibition of cfDNA-associated inflammation and multiple organ injury than naked PEI 1800 (lacking ZIF), and had greater therapeutic efficacy in treating sepsis. These results indicate that PEI-g-ZIF NPs acts as a "nanotrap" that improves upon naked PEI in scavenging circulating cfDNA, reducing inflammation, and reversing the progression of sepsis, thus providing a novel strategy for sepsis treatment.

Photostable and Biocompatible Fluorescent Silicon Nanoparticles for Imaging-Guided Co-Delivery of siRNA and Doxorubicin to Drug-Resistant Cancer Cells.

The development of effective and safe vehicles to deliver small interfering RNA (siRNA) and chemotherapeutics remains a major challenge in RNA interference-based combination therapy with chemotherapeutics, which has emerged as a powerful platform to treat drug-resistant cancer cells. Herein, we describe the development of novel all-in-one fluorescent silicon nanoparticles (SiNPs)-based nanomedicine platform for imaging-guided co-delivery of siRNA and doxorubicin (DOX). This approach enhanced therapeutic efficacy in multidrug-resistant breast cancer cells (i.e., MCF-7/ADR cells). Typically, the SiNP-based nanocarriers enhanced the stability of siRNA in a biological environment (i.e., medium or RNase A) and imparted the responsive release behavior of siRNA, resulting in approximately 80% down-regulation of P-glycoprotein expression. Co-delivery of P-glycoprotein siRNA and DOX led to > 35-fold decrease in the half maximal inhibitory concentration of DOX in comparison with free DOX, indicating the pronounced therapeutic efficiency of the resultant nanocomposites for drug-resistant breast cancer cells. The intracellular time-dependent release behaviors of siRNA and DOX were revealed through tracking the strong and stable fluorescence of SiNPs. These data provide valuable information for designing effective RNA interference-based co-delivery carriers.

Fluorescein sodium ligand-modified silicon nanoparticles produce ultrahigh fluorescence with robust pH- and photo-stability.

Water-dispersed silicon nanoparticles (SiNPs) are facilely prepared in an aqueous phase via microwave-assisted synthesis. The whole synthetic procedure is accomplished in a one-pot microwave reaction, without the requirement of additional surface modification. Remarkably, the resultant SiNPs feature ultrahigh fluorescence (photoluminescent quantum yield (PLQY): ∼90%), robust pH- and photo-stability, and favourable biocompatibility.

Aqueous synthesis of three-dimensional fluorescent silicon-based nanoscale networks featuring unusual anti-photobleaching properties.

We herein present the first example of three-dimensional (3D) fluorescent silicon-based nanoscale networks (SiNNs), which feature unusual anti-photobleaching properties, owing to a unique electronic structure system. This type of fluorescent and biocompatible SiNN, prepared through self-assembly synthesis under microwave irradiation, holds high promise for various optical and electronic applications.

Distinct autophagy-inducing abilities of similar-sized nanoparticles in cell culture and live C. elegans.

Nanomaterial-induced autophagy has raised increasing concerns. A variety of nanomaterials, conventional or recently emerged, have the capability of inducing autophagy. As a consequence, it is becoming a popular belief that induction of autophagy is a common response of cells upon exposure to nanoscale materials. In order to clarify whether the "nanoscale" size is the determining factor for the nanomaterials to induce autophagy, we utilized in vitro cultured cells and an in vivo Caenorhabditis elegans (C. elegans) model to systemically investigate the autophagy-inducing ability of nanomaterials. We selected four types of representative nanomaterials with similar sizes, namely silicon nanoparticles (SiNPs), CdTe quantum dots (QDs), carbon dots (CDs) and gold nanoparticles (AuNPs). We demonstrated that, unlike most other nanomaterials tested, no autophagosome formation was detected in cultured cells or in live C. elegans with SiNP treatment. The expression of autophagy-related genes and the lipidation of LGG-1/LC3 in cells and C. elegans also remained unchanged after the treatment of SiNPs. In addition, the ability of the nanomaterials to induce autophagy appeared to correlate with those to incur subcellular organelle damage. Together, our studies demonstrate that SiNPs do not induce autophagy in vitro or in vivo in the selected model organisms and cell lines, thus clarifying that the "nanoscale" size is not the determining factor for the nanomaterials to induce autophagy. The results also suggest that the autophagy-inducing ability of most nanomaterials could be merely a reflection of their detrimental effect on cellular structures.

Biocompatible protamine sulfate@silicon nanoparticle-based gene nanocarriers featuring strong and stable fluorescence.

The development of biocompatible and fluorescent gene carriers is of particular importance in the gene-delivery field. Taking advantage of the unique optical properties (e.g., strong and robust fluorescence) of silicon nanoparticles (SiNPs), as well as the excellent biocompatibility of silicon and protamine sulfate (PS, approved by the U.S. Food and Drug Administration (FDA) for clinical use), we herein present a type of PS-modified SiNP (PS@SiNP)-based gene carrier. Plasmid DNA (pDNA) with negative charges can be effectively bound onto the surface of the as-prepared fluorescent PS@SiNP-based gene carriers via electrostatic interactions. In particular, such resultant gene carriers possess stable and high fluorescence (photoluminescent quantum yield (PLQY): ∼25%). In addition, the PS@SiNP-based gene carriers show minimal toxic effects on normal mitochondrial metabolic activity (e.g., human retinal pigment epithelial (ARPE-19) cells preserve ∼90% of their cell viability after a 48 h incubation with the resultant carriers). Based on tracking the strong and stable fluorescence signals of SiNPs, the dynamic behavior of the PS@SiNP-based gene carriers in live cells (e.g., clathrin-mediated endocytosis, lysosomal escape, pDNA release, etc.) is investigated in a long-term manner, providing valuable information for understanding the intracellular behavior of gene vectors and designing high-efficacy gene carriers.

Fluorescent and magnetic anti-counterfeiting realized by biocompatible multifunctional silicon nanoshuttle-based security ink.

Herein, we present the first example of a silicon nanoshuttle-based security ink simultaneously featuring attractive optical and magnetic properties, suitable for fluorescent and magnetic anti-counterfeiting and encryption. Significantly, the information can be dual-encrypted through multi-color fluorescence and longitudinal (T1)/transverse (T2) relaxation contrast by using the silicon nanoshuttle-based security ink. We further demonstrate the feasibility of this high-performance ink for practical application in banknote anti-counterfeiting.

One-dimensional silicon nanoshuttles simultaneously featuring fluorescent and magnetic properties.

We herein present the first example of one-dimensional silicon nanostructures (i.e., silicon nanoshuttles (SiNSs)), which simultaneously feature bright fluorescence, robust photostability, and distinct paramagnetism. This type of SiNSs, prepared through one-pot microwave chemical synthesis in a rapid and facile manner, hold high promise for various optical and magnetic applications.

In vitro cellular behaviors and toxicity assays of small-sized fluorescent silicon nanoparticles.

Extensive investigations have been carried out for evaluating the toxicology of various nanomaterials (e.g., carbon- and metal-based nanomaterials), which offer invaluable information for assessing the feasibility of nanomaterial-based wide-ranging applications. In recent years, sufficient efforts have been made to develop fluorescent small-sized silicon nanoparticles (SiNPs) as a novel optical material simultaneously featuring strong fluorescence and ultrahigh photostability, providing high promise for a myriad of biological, biomedical and electronic applications. It is worth pointing out that, despite the non- or low-toxicity of silicon, sufficient and objective toxicology evaluation of SiNPs is urgently required at both the in vitro and in vivo levels. However, there currently exists scanty information about the intracellular behaviors of the SiNPs, particularly the underlying mechanism of entry into cells and intracellular fate. Herein, we present a report aimed at determining the uptake and intracellular transport of SiNPs of ca. 4 nm diameter. Taking advantage of the strong and stable fluorescent signals of SiNPs, we reveal that these small-sized SiNPs accumulate in the plasma membrane prior to internalization, and are further internalized predominantly by clathrin-mediated and caveolae-dependent endocytosis. After endocytosis, the SiNPs are localized in early endosomes within a short time (∼1 h), while in up to 24 h of incubation the SiNPs are mainly transported to lysosomes in a microtubule-dependent way; and interestingly, to a smaller extent are sorted to the Golgi apparatus. Moreover, we demonstrate that there are no toxic effects of SiNPs on the cell metabolic activity and integrity of the plasma membrane.

Subcellular distribution and cellular self-repair ability of fluorescent quantum dots emitting in the visible to near-infrared region.

Semiconductor II-VI quantum dots (QDs), as high-performance fluorescent biological probes, have garnered significant attention due to their superior optical properties. To enable QDs for wide-ranging bioapplications, concerns about their in vitro behavior need to be fully addressed. Herein, for the first time, cellular behaviors of aqueous synthesized-QDs (aqQDs), whose maximum emission wavelength (λ emission) covers the visible to near-infrared spectral window, are systematically investigated. Our results demonstrate that three different sized aqQDs feature distinct cellular distributions, i.e. aqQD530 (aqQDs whose λ emission is 530 nm) and aqQD620 (aqQDs whose λ emission is 620 nm) mainly distribute in the cytoplasm and nucleus, while aqQD730 (aqQDs whose λ emission is 730 nm) mainly accumulates in the cytoplasm. Most significantly, the phenomenon that cellular self-repair ability is dependent on diameters of aqQDs is revealed for the first time. In particular, small-sized QDs (e.g. aqQD530 and aqQD620) severely deteriorate cellular self-repair ability, leading to an irreversible decrease in cell viability. In striking contrast, large-sized QDs (e.g. aqQD730) have little effect on cellular self-repair ability, and the cell viability is restored after removal of aqQD730 from the culture medium. Our results provide invaluable information for QD-relevant biosafety analysis, as well as suggest available guidance for the design of biocompatible QDs for wide utilization in biological and biomedical studies.

In situ rapid growth of fluorescent silicon nanoparticles at room temperature and under atmospheric pressure.

Herein, we demonstrate that at room temperature (20-25 °C) and under atmospheric pressure, small-sized (∼3.1 nm) SiNPs can be rapidly formed in aqueous phase within 60 min, with high photoluminescence quantum yield (PLQY) of ∼50%. This approach is readily scalable and could potentially be used to produce high-quality SiNPs at an industrial level.

Aqueous synthesized quantum dots interfere with the NF-κB pathway and confer anti-tumor, anti-viral and anti-inflammatory effects.

The NF-κB pathway plays crucial roles in inflammatory responses and cell survival. Aberrant constitutive NF-κB activation is associated with various human diseases including cancer and inflammatory and auto-immune diseases. Consequently, it is highly desirable to develop new kinds of inhibitors, which are highly efficacious for blocking the NF-κB pathway. In this study, by using a typical kind of aqueous synthesized quantum dots (QDs), i.e., CdTe QDs, as a model, we for the first time demonstrated that the QDs could selectively affect the cellular nuclear factor-κB (NF-κB) signaling pathway, but do not affect the AKT or ERK pathways. Typically, the QDs efficiently inhibited the activation of IKKα and IKKß, resulting in the suppression of both the canonical and the non-canonical NF-κB signaling pathways. Inhibition of NF-κB by QDs downregulates anti-apoptotic genes and promotes apoptosis in cancer cells. The QDs induced NF-κB inhibition and cytotoxicity could be blocked by N-acetylcysteine due to the reduced cellular uptake of QDs. Importantly, inhibition of NF-κB by QDs displayed promising effects against the viral replication and in vivo bacterial endotoxin-induced inflammatory responses. These data suggest the QDs as potent inhibitors of the NF-κB signaling pathway, both in vitro and in vivo. Our findings highlight the potential of using QDs in the development of anti-cancer, anti-viral, and anti-inflammatory approaches, and also facilitate better understanding of QDs-related cellular behavior under the molecular level.

Plant-derived fluorescent silicon nanoparticles featuring excitation wavelength-dependent fluorescence spectra for anti-counterfeiting applications.

By using gramineae plants as natural and accessible reaction precursors, we herein introduce a green synthetic strategy, which is efficacious for the facile production of crystalline, excitation-wavelength-dependent fluorescent and small-sized silicon nanoparticles (SiNPs). We further explore the prepared SiNPs as a novel kind of fluorescent label for anti-counterfeiting applications.