Global gene expression analysis of cellular death mechanisms induced by mesoporous silica nanoparticle-based drug delivery system

Nanodelivery systems: An efficient and target-specific approach for drug-resistant cancers

BACKGROUND

Cancer treatment is still a global health challenge. Nowadays, chemotherapy is widely applied for treating cancer and reducing its burden. However, its application might be in accordance with various adverse effects by exposing the healthy tissues and multidrug resistance (MDR), leading to disease relapse or metastasis. In addition, due to tumor heterogeneity and the varied pharmacokinetic features of prescribed drugs, combination therapy has only shown modestly improved results in MDR malignancies. Nanotechnology has been explored as a potential tool for cancer treatment, due to the efficiency of nanoparticles to function as a vehicle for drug delivery.

METHODS

With this viewpoint, functionalized nanosystems have been investigated as a potential strategy to overcome drug resistance.

RESULTS

This approach aims to improve the efficacy of anticancer medicines while decreasing their associated side effects through a range of mechanisms, such as bypassing drug efflux, controlling drug release, and disrupting metabolism. This review discusses the MDR mechanisms contributing to therapeutic failure, the most cutting-edge approaches used in nanomedicine to create and assess nanocarriers, and designed nanomedicine to counteract MDR with emphasis on recent developments, their potential, and limitations.

CONCLUSIONS

Studies have shown that nanoparticle-mediated drug delivery confers distinct benefits over traditional pharmaceuticals, including improved biocompatibility, stability, permeability, retention effect, and targeting capabilities.

Janus Silica Nanoparticle-Based Tumor Microenvironment Modulator for Restoring Tumor Sensitivity to Programmed Cell Death Ligand 1 Immune Checkpoint Blockade Therapy

An immunosuppressive tumor microenvironment (TME) with inadequate and exhausted tumor-infiltrating cytotoxic lymphocytes and abundant cellular immunosuppressors is the major obstacle responsible for the poor efficacy of PD-1/PD-L1 (programmed cell death 1 and its ligand 1) immune checkpoint blockade (ICB) therapy. Herein, a Janus silica nanoparticle (JSNP)-based immunomodulator is explored to reshape the TME for boosting the therapeutic outcomes of αPD-L1 therapy. The designed JSNP has two distinct domains, namely, an ultra pH-responsive side (UPS), which could encapsulate PI3Kγ inhibitor IPI549 in the pore structure, and a polycation-grafted intra-glutathione (GSH)-sensitive side (IGS), which could absorb CXCL9 cDNA on the surface. The final IPI549@UPS-IGS-PDMAEMA@CXCL9 cDNA (IUIPC) could release IPI549 in weak acid TME to target myeloid-derived suppressor cells (MDSCs) to reverse negative immunoregulation and then release CXCL9 cDNA in tumor cells with abundant GSH for sustained CXCL9 chemokine expression and secretion to improve cytotoxic lymphocyte recruitment signals, thereby jointly restoring tumor sensitivity to PD-1/PD-L1 ICB therapy. As expected, the IUIPC-mediated TME remodeling during αPD-L1 therapy significantly ameliorated TME immunosuppression, as well as induced potent systemic antitumor immune responses, which ultimately achieved a robustly boosted antitumor efficacy proven by remarkable suppression of primary tumor growth, obvious prevention of tumor recurrence, and significant regression of abscopal tumors. Hence, the IUIPC-mediated TME-regulating strategy provides an enormous perspective for the improvement of PD-1/PD-L1 ICB therapy.

Multifunctional manganese-containing vaccine delivery system Ca@MnCO3/LLO for tumor immunotherapy

The ideal vaccine delivery systems can not only deliver antigens in intelligent manners but also act as adjuvants. Recently found that Mn²⁺ can effectively stimulate anti-tumor immune responses, and Ca²⁺ can regulate autophagy to promote the cross-presentation of antigens. Thus, we constructed such a manganese-containing multimode vaccine delivery system by using calcium-doped manganese carbonate microspheres (Ca@MnCO₃) and perforin-listeria hemolysin (LLO), as termed as Ca@MnCO₃/LLO. The two components Ca@MnCO₃ and LLO, not only act as vaccine adjuvants by themselves, but also contribute to achieve cellular immunity. Among them, Ca@MnCO₃ microspheres as an excellent Mn²⁺ and Ca²⁺ reservoir, can continuously release adjuvants Mn²⁺ and Ca²⁺ to enhance immune response in dendritic cells, while LLO can contribute to induce lysosomal escape. Particularly, Ca²⁺ was added firstly to MnCO₃ microspheres to improve the stability and load capacity of the microspheres. Along with the degradation of intracellular Ca@MnCO₃ microspheres, and the lysosomal membrane-lytic effects of perforin LLO, the Mn²⁺, Ca²⁺ and OVA were released to the cytoplasm. These outcomes cooperatively promote antigen cross-presentation, elicit CD8⁺ T cell proliferation, and finally achieve prominent anti-tumor effects. The results indicate that the manganese-containing vaccine delivery system Ca@MnCO₃/LLO provides a promising platform for the construction of tumor vaccines.

Regulatory Effects of Damaged Renal Epithelial Cells After Repair by Porphyra yezoensis Polysaccharides with Different Sulfation Degree on the Calcium Oxalate Crystal-Cell Interaction

BACKGROUND

The interaction between urinary microcrystals and renal epithelial cells is closely related to kidney stone formation. However, the mechanism of cell state changes that affect crystal-cell interaction remains unclear.

METHODS

This study investigated the relationship between the sulfate group (-OSO3 -) content in Porphyra yezoensis polysaccharide (PYP) and the ability to repair damaged cells, as well as the changes in cell adhesion and endocytosis of nano-calcium oxalate monohydrate (COM) crystals before and after PYP repair of damaged renal tubular epithelial cells. The sulfur trioxide-pyridine method was used to sulfate PYP (-OSO3 - content of 14.14%), and two kinds of sulfated PYPs with -OSO3 - content of 20.28% (SPYP1) and 27.14% (SPYP2) were obtained. The above three PYPs were used to repair oxalate-damaged human proximal tubular epithelial cells (HK-2), and the changes in the biochemical indicators of the cells before and after the repair and the changes in cell adhesion and endocytosis of nano-COM crystals were detected.

RESULTS

After repair by PYPs, the cell viability increased, the number of reactive oxygen species decreased, and the reduction of mitochondrial membrane potential and the release of intracellular Ca2+ were suppressed. The cells repaired by PYPs inhibited the adhesion of nano-COM crystals while promoting the endocytosis of the adhered crystals. The endocytosed crystals mainly accumulated in the lysosome. The ability of PYPs to repair cell damage, inhibit crystal adhesion, and promote crystal endocytosis was enhanced when the -OSO3 - content increased. Among them, SPYP2 with the highest -OSO3 - content showed the best biological activity.

CONCLUSION

SPYP2 showed the best ability to repair damaged cells, followed by SPYP1 and PYP. SPYP2 may become a potential green drug that inhibits the formation and recurrence of calcium oxalate stones.

Safety Assessments of Nickel Boride Nanoparticles on the Human Pulmonary Alveolar Cells by Using Cell Viability and Gene Expression Analyses

Nickel boride is generally used in the steel industry as a melting accelerator due to its feature of creating a protective and stable attribute at high temperatures. It is also used to improve the hardenability of the steel with boron addition in the production. Thus, safety studies and biocompatibility analysis of nickel boride should be performed comprehensively to understand the limitations of use in various areas. In the present study, nickel boride nanoparticles (Ni₂B NPs) were synthesized by a single-step method and molecule characterizations were performed via the use of X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analyses. Cytotoxicity properties of Ni₂B NPs were identified on human pulmonary alveolar epithelial cells (HPAEpiC) by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), neutral red (NR), and lactate dehydrogenase (LDH) assays. Illumina human ht-12 v4.0 whole-genome microarray analysis was conducted to investigate NiB₂ NPs effects on gene expression regulations of HPAEpiC cells. The database for annotation, visualization, and integrated discovery (DAVID) analysis was performed to reveal the relationship between Ni₂B NP application and cellular pathway alterations. According to cytotoxicity analysis, the IC₅₀ value for Ni₂B NP application was found as 81.99 mg/L concentration. Microarray analysis of Ni₂B NP application was shown for the first time that 693 gene expression changes (FC ≥ 2) occurred significantly over 40.000 gene probes and Ni₂B NPs were observed to affect microtubule regulation, centrosome organization, and phosphoprotein synthesis.

Bifunctional, Copper-Doped, Mesoporous Silica Nanosphere-Modified, Bioceramic Scaffolds for Bone Tumor Therapy

In the traditional surgical intervention procedure, residual tumor cells may potentially cause tumor recurrence. In addition, large bone defects caused by surgery are difficult to self-repair. Thus, it is necessary to design a bioactive scaffold that can not only kill residual tumor cells but also promote bone defect regeneration simultaneously. Here, we successfully developed Cu-containing mesoporous silica nanosphere-modified β-tricalcium phosphate (Cu-MSN-TCP) scaffolds, with uniform and dense nanolayers with spherical morphology via 3D printing and spin coating. The scaffolds exhibited coating time- and laser power density-dependent photothermal performance, which favored the effective killing of tumor cells under near-infrared laser irradiation. Furthermore, the prepared scaffolds favored the proliferation and attachment of rabbit bone marrow-derived mesenchymal stem cells and stimulated the gene expression of osteogenic markers. Overall, Cu-MSN-TCP scaffolds can be considered for complete eradication of residual bone tumor cells and simultaneous healing of large bone defects, which may provide a novel and effective strategy for bone tumor therapy. In the future, such Cu-MSN-TCP scaffolds may function as carriers of anti-cancer drugs or immune checkpoint inhibitors in chemo-/photothermal or immune-/photothermal therapy of bone tumors, favoring for effective treatment.

Nanotechnological approaches for counteracting multidrug resistance in cancer

Every year, cancer accounts for a vast portion of deaths worldwide. Established clinical protocols are based on chemotherapy, which, however, is not tumor-selective and produces a series of unbearable side effects in healthy tissues. As a consequence, multidrug resistance (MDR) can arise causing metastatic progression and disease relapse. Combination therapy has demonstrated limited responses in the treatment of MDR, mainly due to the different pharmacokinetic properties of administered drugs and to tumor heterogeneity, challenges that still need to be solved in a significant percentage of cancer patients. In this perspective, we briefly discuss the most relevant MDR mechanisms leading to therapy failure and we report the most advanced strategies adopted in the nanomedicine field for the design and evaluation of ad hoc nanocarriers. We present some emerging classes of nanocarriers developed to reverse MDR and discuss recent progress evidencing their limits and promises.

Adsorption of Cellulase on Wrinkled Silica Nanoparticles with Enhanced Inter-Wrinkle Distance

Mesoporous silica materials offer a unique opportunity for enzyme immobilization thanks to their properties, such as tuneable pore size, large surface area and easy functionalization. However, a significant enhancement of cellulase enzyme activity entrapped inside the silica pores still represents a challenge. In this work, we immobilized cellulase by adsorption on wrinkled silica nanoparticles (WSNs), obtaining an active and stable biocatalyst. We used pentanol as co-solvent to synthesize WSNs with enhanced inter-wrinkle distance in order to improve cellulase hosting. The physical-chemical and morphological characterization of WSNs and cellulase/WSNs was performed by thermogravimetric (TG), Fourier transform infrared (FT-IR), and transmission electron microscopy (TEM) analyses. The obtained results showed that this matrix generates a favourable microenvironment for hosting cellulase. The results of the catalytic assays and operational stability confirmed the key role of size, morphology and distribution of the pores in the successful outcome of the cellulase immobilization process. The immobilization procedure used allowed preserving most of the secondary structure of the enzyme and, consequently, its catalytic activity. Moreover, the same value of glucose yield was observed for five consecutive runs, showing a high operational stability of the biocatalyst.

Macrophage-cancer hybrid membrane-coated nanoparticles for targeting lung metastasis in breast cancer therapy

Cell membrane- covered drug-delivery nanoplatforms have been garnering attention because of their enhanced bio-interfacing capabilities that originate from source cells. In this top-down technique, nanoparticles (NPs) are covered by various membrane coatings, including membranes from specialized cells or hybrid membranes that combine the capacities of different types of cell membranes. Here, hybrid membrane-coated doxorubicin (Dox)-loaded poly(lactic-co-glycolic acid) (PLGA) NPs (DPLGA@[RAW-4T1] NPs) were fabricated by fusing membrane components derived from RAW264.7(RAW) and 4T1 cells (4T1). These NPs were used to treat lung metastases originating from breast cancer. This study indicates that the coupling of NPs with a hybrid membrane derived from macrophage and cancer cells has several advantages, such as the tendency to accumulate at sites of inflammation, ability to target specific metastasis, homogenous tumor targeting abilities in vitro, and markedly enhanced multi-target capability in a lung metastasis model in vivo. The DPLGA@[RAW-4T1] NPs exhibited excellent chemotherapeutic potential with approximately 88.9% anti-metastasis efficacy following treatment of breast cancer-derived lung metastases. These NPs were robust and displayed the multi-targeting abilities of hybrid membranes. This study provides a promising biomimetic nanoplatform for effective treatment of breast cancer metastasis.

Biomineralized nanosilica-based organelles endow living yeast cells with non-inherent biological functions

We propose a biomimetic strategy to construct engineered yeast cells (EYCs) by building intracellular silica nanoscaffolds as biomimetic organelles. These nanosilica-based organelles can coordinate with loaded drug and yeast as a shell could prevent drug leakage. In vivo results show that EYCs serve as a dually responsive drug delivery system, targeted with extracellular caps (folate) and triggered by intracellular SiO2 at the low pH of cancer tissue.

Autophagy Modulated by Inorganic Nanomaterials

With the rapid development of nanotechnology, inorganic nanomaterials (NMs) have been widely applied in modern society. As human exposure to inorganic NMs is inevitable, comprehensive assessment of the safety of inorganic NMs is required. It is well known that autophagy plays dual roles in cell survival and cell death. Moreover, inorganic NMs have been proven to induce autophagy perturbation in cells. Therefore, an in-depth understanding of inorganic NMs-modulated autophagy is required for the safety assessment of inorganic NMs. This review presents an overview of a set of inorganic NMs, consisting of iron oxide NMs, silver NMs, gold NMs, carbon-based NMs, silica NMs, quantum dots, rare earth oxide NMs, zinc oxide NMs, alumina NMs, and titanium dioxide NMs, as well as how each modulates autophagy. This review emphasizes the potential mechanisms underlying NMs-induced autophagy perturbation, as well as the role of autophagy perturbation in cell fate determination. Furthermore, we also briefly review the potential roles of inorganic NMs-modulated autophagy in diagnosis and treatment of disease.

Comparison of the adhesion and endocytosis of calcium oxalate dihydrate to HK-2 cells before and after repair by Astragalus polysaccharide

This work investigated the effects of repairing injured renal proximal tubular epithelial (HK-2) cells by using three Astragalus polysaccharides (APS) with different molecular weights and the adhesion and endocytosis of HK-2 cells to the calcium oxalate dihydrate (COD) nanocrystals before and after repair to develop new products that can protect against kidney stones. HK-2 cells cultured in vitro were injured with 2.6 mmol/L oxalic acid to establish a damaged cell model. Three kinds of APS (APS0, APS1, and APS2 with molecular weights of 11.03, 4.72, and 2.60 kDa, respectively) were used to repair the damaged cells. The changes in the adhesion and endocytosis of 100 nm COD crystals to cells before and after the repair were detected. After the repair of HK-2 cells by the APS, the speed of wound healing of the damaged HK-2 cells increased, and the amount of phosphatidylserine (PS) ectropion decreased. In addition, the proportion of cells with adhered COD crystals decreased, whereas the proportion of cells with internalized crystals increased. As a result of the repair activity, APS can inhibit the adhesion and promote the endocytosis of COD nanocrystals to damaged cells. APS1, which had a moderate molecular weight, displayed the strongest abilities to repair the cells, inhibit adhesion, and promote endocytosis. Thus, APS, particularly APS1, may serve as potential green drugs for preventing kidney stones.

Organosilica-Based Hollow Mesoporous Bilirubin Nanoparticles for Antioxidation-Activated Self-Protection and Tumor-Specific Deoxygenation-Driven Synergistic Therapy

A major concern about glucose oxidase (GOx)-mediated cancer starvation therapy is its ability to induce serious oxidative damage to normal tissues through the massive production of H₂O₂ byproducts in the oxygen-involved glucose decomposition reaction, which may be addressed by using a H₂O₂ scavenger, known as an antioxidation agent. Surprisingly, H₂O₂ removal accelerates the aerobic glycometabolism of tumors by activating the H₂O₂-dependent "redox signaling" pathway of cancer cells. Simultaneous oxygen depletion further aggravates tumor hypoxia to increase the toxicity of a bioreductive prodrug, such as tirapazamine (TPZ), thereby improving the effectiveness of cancer starvation therapy and bioreductive chemotherapy. Herein, a "nitrogen-protected silica template" method is proposed to design a nanoantioxidant called an organosilica-based hollow mesoporous bilirubin nanoparticle (HMBRN), which can act as an excellent nanocarrier to codeliver GOx and TPZ. In addition to efficient removal of H₂O₂ for self-protection of normal tissues via antioxidation, GOx/TPZ-coloaded HMBRN can also rapidly deplete intratumoral glucose/oxygen to promote a synergistic starvation-enhanced bioreductive chemotherapeutic effect for the substantial suppression of solid tumor growth. Distinct from the simple combination of two treatments, this study introduces antioxidation-activated self-protection nanotechnology for the significant improvement of tumor-specific deoxygenation-driven synergistic treatment efficacy without additional external energy input, thus realizing the renaissance of precise endogenous cancer therapy with negligible side effects.

Shape-dependent adhesion and endocytosis of hydroxyapatite nanoparticles on A7R5 aortic smooth muscle cells

The interaction between nanohydroxyapatite (HAP) and smooth muscle cells is an important step in vascular calcification. However, the effect of the shape of HAP on adhesion and endocytosis to aortic smooth muscle cells has been rarely reported. Four different morphological HAP crystals (H-Rod, H-Needle, H-Sphere, and H-Plate) were selected to interact with rat aortic smooth muscle cells (A7R5). Fluorescence-labeled HAP was used to detect crystal adhesion and endocytosis and then pretreated with different endocytic inhibitors to explore the pathway of endocytotic crystals. The distribution of crystals inside and outside the cells and the crystal localization in lysosomes was observed through laser confocal microscopy. The effect of crystal on the cell cycle and the changes in the expression of phosphatidylserine, osteopontin, α-actin, core binding factor alpha 1, and osterix on the surface of A7R5 cells were detected. The adhesion and endocytosis of HAP on A7R5 cells were closely related to crystal shapes and ranked as follows: H-Plate > H-Sphere > H-Needle > H-Rod. H-Sphere and H-Needle were internalized into the cells mainly via the clathrin-mediated pathway, whereas H-Plate and H-Rod were internalized into the cells mainly via macropinocytosis. The endocytosed nano-HAP was mainly distributed in the cell lysosome. The adhesion and endocytosis of HAP to A7R5 cells were positively correlated with the specific surface area, and contact area of HAP and negatively correlated with the absolute value of Zeta and contact angle of HAP. This study provided insights into the effect of crystal morphology on vascular calcification and its mechanism.

Direct Observation of Nanoparticles within Cells at Subcellular Levels by Super-Resolution Fluorescence Imaging

Direct observation of nanoparticles with high spatial resolution at subcellular levels is of great importance to understand the nanotoxicology and promote the biomedical applications of nanoparticles. Super-resolution fluorescence microscopy can break the diffraction resolution limit to achieve spatial resolution of tens of nanometers, making it ideal for highly accurate observation of nanoparticles in the cellular world. In this study, we introduced the employment of super-resolution fluorescence imaging for monitoring nanoparticles within cells. Carbocyanine dyes Alexa Flour 647 labeled mesoporous silica nanoparticles (designated as MSNs-AF647) were constructed as the super-resolution imaging nanoplatform in this work as proof of concept. The MSNs-AF647 were incubated with Hela cells, and the nanoparticles within cells were further monitored by super-resolution fluorescence microscopy. The fluorescence images of MSNs-AF647 within cells captured with the super-resolution fluorescence microscopy showed a much higher spatial resolution than that obtained using conventional fluorescence microscopy, showing that super-resolution fluorescence images can provide more accurate information to locate the nanoparticles at the subcellular levels. Moreover, other functional molecules can be easily loaded into the MSNs-AF647 super-resolution imaging nanoplatform, which suggested that super-resolution fluorescence imaging can further be applied to various bioimaging-related areas, such as imaging-guided therapy, with the aid of the MSNs-AF647 nanoplatform. This study demonstrates that super-resolution fluorescence microscopy offers a highly accurate method to study nanoparticles in the cellular world. We anticipate this strategy may further be applied to research areas such as studying the nanotoxicology and optimization of nanoparticle-based bioprobes or drugs by designing new nanostructured materials with multifunctional properties based on MSNs-AF647.

Differentiation regulation of mesenchymal stem cells via autophagy induced by structurally-different silica based nanobiomaterials

Autophagy is associated with the proliferation and differentiation of mesenchymal stem cells (MSCs). In this study, we investigated the biological impact of silica-based nanobiomateiral-induced autophagy on the differentiation of MSCs, in which the nanoparticulate cues include solid silica nanoparticles (SSN), mesoporous silica nanoparticles (MSN) and biodegradable mesoporous silica nanoparticles (DMSN). The treatment with SSN significantly up-regulated the LC3-II expression via ERK1/2 and AKT/mTOR signaling pathways compared to DMSN and MSN, leading to a higher autophagic activity in MSCs. The enhanced protein adsorption of DMSN and MSN could prevent the direct interaction between cells and nanoparticles, which consequently reduces the autophagic stimulation of MSCs. It should be noted that MSCs exhibited increased differentiation potential when the autophagic activity was enhanced by the treatment with different nanoparticles. In comparison, no difference in the cell differentiation potential was found when an autophagy inhibitor (chloroquine, CQ) was incorporated in all groups. The study may contribute to the development of silica-based nanobiomaterials in the future.

Genotoxicity of amorphous silica nanoparticles: Status and prospects

Amorphous silica nanoparticles (SNPs) are widely used in biomedical applications and consumer products. Little is known, however, about their genotoxicity and potential to induce gene expression regulation. Despite recent efforts to study the underlying mechanisms of genotoxicity of SNPs, inconsistent results create a challenge. A variety of factors determine particle-cell interactions and underlying mechanisms. Further, high-throughput studies are required to carefully assess the impact of silica nanoparticle physicochemical properties on induction of genotoxic response in different cell lines and animal models. In this article, we review the strategies available for evaluation of genotoxicity of nanoparticles (NPs), survey current status of silica nanoparticle gene alteration and genotoxicity, discuss particle-mediated inflammation as a contributing factor to genotoxicity, identify existing gaps and suggest future directions for this research.

Cancer cell membrane-cloaked mesoporous silica nanoparticles with a pH-sensitive gatekeeper for cancer treatment

Nanoparticular drug delivery system (NDDS) has great potential for enhancing the efficacy of traditional chemotherapeutic drugs. However, it is still a great challenge to fabricate a biocompatible NDDS with simple structure capable of optimizing therapeutic efficacy, such as high tumor accumulation, suitable drug release profile (e.g. no premature drug leakage in normal physiological conditions while having a rapid release in cancer cells), low immunogenicity, as well as good biocompatibility. In this work, a simple core/shell structured nanoparticle was fabricated for prostate cancer treatment, in which a mesoporous silica nanoparticle core was applied as a container to high-efficiently encapsulate drugs (doxorubicin, DOX), CaCO₃ interlayer was designed to act as sheddable pH-sensitive gatekeepers for controlling drug release, and cancer cell membrane wrapped outlayer could improve the colloid stability and tumor accumulation capacity. In vitro cell experiments demonstrated that the as-prepared nanovehicles (denoted as DOX/MSN@CaCO₃@CM) could be efficiently uptaken by LNCaP-AI prostate cancer cells and even exhibited a better anti-tumor efficiency than free DOX. In addition, Live/Dead cell detection and apoptosis experiment demonstrated that MSN/DOX@CaCO₃@CM could effectively induce apoptosis-related death in prostate cancer cells. In vivo antitumor results demonstrated that DOX/MSN@CaCO₃@CM administration could remarkably suppress the tumor growth. Compared with other tedious approaches to optimize the therapeutic efficacy, this study provides an effective drug targeting system only using naturally biomaterials for the treatment of prostate cancer, which might have great potential in clinic usage.

pH/hypoxia programmable triggered cancer photo-chemotherapy based on a semiconducting polymer dot hybridized mesoporous silica framework

Although photothermal therapy (PTT) has become a compelling strategy for cancer therapy, few studies concern the physiological consequences of PTT ablation. Herein, we discover that PTT-induced hyperthermia can aggravate tumor hypoxia, which may increase the risk of tumor recurrence and reduce PTT efficacy. We thus integrated the pH/hypoxia-triggered Fe(iii)-banoxantrone (AQ4N) prodrug and semiconducting polymer dots (SPs) for programmable triggered cancer photothermal-chemotherapy. A SP-hybridized mesoporous silica framework, decorated by dopamine and polyethylene glycol, named PPMSF, was synthesized by a simple method, and then served as an efficient photo-absorbing agent (PTA) and drug carrier. Fe(iii)-AQ4N and Mn(ii) were then coordinated with PPMSF (abbreviated Mn-APPMSF) via coordination effects. The nanohybrids exhibited tumor micro-environment pH triggered drug release. Under the irradiation of NIR light, magnetic resonance imaging (MRI) tracked the accumulation of the nanohybrids in tumors which then destroyed tumor cells by local hyperthermia, this can consequently aggravate the tumor hypoxia levels. Intriguingly, the aggravated hypoxia can further enhance the reduction of AQ4N to significantly improve therapeutic efficacy and effectively inhibit tumor growth when compared with traditional PTT. These results indicate the potential of our nanohybrids as a programmable synergistic agent for cancer therapy.

Probing Cellular Processes Using Engineered Nanoparticles

Nanoparticles, the building blocks of nanotechnology, have been widely utilized in various biomedical applications, such as detection, diagnosis, imaging, and therapy. However, another emerging, albeit under-represented, area is the employment of nanoparticles as tools to understand cellular processes (e.g., oxidative stress-induced signaling cascades). Such investigations have enormous potential to characterize a disease from a different perspective and unravel some new features that otherwise would have remained a mystery. In this review, we summarize the intrinsic biological properties of unmodified as well surface modified nanoparticles and discuss how such properties could be utilized to interrogate biological processes and provide a perspective for future evolution of this field.

Photoresponsive Nanovehicle for Two Independent Wavelength Light-Triggered Sequential Release of P-gp shRNA and Doxorubicin To Optimize and Enhance Synergistic Therapy of Multidrug-Resistant Cancer

Prerelease of RNA molecules than chemotherapeutic drugs with a sufficient interval is a vital prerequisite for RNA/drug co-delivery strategy to overcome multidrug resistance (MDR) of cancer cells, but how to precisely control their release at different time points is still a grand challenge up to now. This study aims to on-demand remotely manipulate RNA and drug release in real time through single delivery system to sequentially play their respective roles for optimizing and enhancing their synergistic antitumor effects. To this end, a photoresponsive mesoporous silica nanoparticle (PMSN) is fabricated as a co-delivery vehicle of P-glycoprotein (P-gp) short-hairpin RNA (shRNA) and photocaged prodrug of doxorubicin (DOX), by which the orthogonal and sequential release of shRNA and DOX can be achieved using an external light. In our design, the cationic poly[2-( N, N-dimethylaminoethyl)methacrylate] is introduced onto the PMSN surface through a light-sensitive coumarin ester derivative linker to adsorb P-gp shRNA, whereas the photocleavable o-nitrobenzyl ester derivative-caged DOX is loaded into the inner pores of the PMSN. The PMSN is found to be effectively internalized by MDR cancer cells, and the release of the shRNA and DOX is demonstrated to be independently regulated by 405 and 365 nm light irradiations due to selectively cleaved coumarin and o-nitrobenzyl ester, resulting in enhanced drug retention, and finally bring out optimized and significantly improved chemotherapeutic effects both in vitro and in vivo for MDR cancer treatment, which might hold extensive application prospects in MDR cancer treatment in future.

Fe Doped Magnetic Nanodiamonds Made by Ion Implantation as Contrast Agent for MRI

We report in this paper a new MRI contrast agent based on magnetic nanodiamonds fabricated by Fe ion implantation. The Fe atoms that are implanted into the nanodiamonds are not in direct contact with the outside world, enabling this new contrast agent to be free from cell toxicity. The image enhancement was shown clearly through T2 weighted images. The concentration dependence of the T2 relaxation time gives a relaxivity value that is about seven times that of the regular non-magnetic nanodiamonds. Cell viability study has also been performed. It was shown that they were nearly free from cytotoxicity independent of the particle concentration used. The imaging capability demonstrated here adds a new dimension to the medical application of nanodiamonds. In the future one will be able to combine this capability of magnetic nanodiamonds with other functions through surface modifications to perform drug delivery, targeted therapy, localized thermal treatment and diagnostic imaging at the same time.

Humic acid alleviates the ecotoxicity of graphene-family materials on the freshwater microalgae Scenedesmus obliquus

The extensive application of graphene-family materials (GFMs) has increased its potential risk to aquatic organisms. However, the influence of humic acid (HA) on the biotoxicity of GFMs has not clarified. Here, we conduct a study on the toxicity of four GFMs, i.e. graphene (G), graphene oxide (GO), carboxyl-modified graphene (G-COOH) and amine-modified graphene (G-NH₂), with or without HA, using Scenedesmus obliquus (S. obliquus) as model organism. Our results showed that the four GFMs induced significant inhibition on cell growth and Chlorophyll-a (Chl-a) synthesis, loss of cell viability and membrane integrity as well as mitochondrial membrane potential (MMP), where G exhibited the highest toxicity with median effect concentration (EC₅₀) of 8.2 mg L^-1, and G-NH₂ exhibited the lowest toxicity with EC₅₀ of 84.0 mg L^-1. Meanwhile, HA mitigated the toxicity of GFMs in the order of G-NH₂ > G-COOH > GO > G for the most of endpoints. Furthermore, three possible mechanisms of the HA alleviation on toxicity were speculated as: (1) reduce the contact of GFMs with algae cells through regulating the structures and surface negative charges of GFMs; (2) mitigate physical penetration and damage through decreasing the deposition of GFMs on cells by interacting with HA; (3) react as an antioxidant with intracellular reactive oxygen species (ROS) and extracellular hydroxyl radical (OH). This work provides useful information for the environmental toxicity of GFMs and the possible antidotal mechanisms in the presence of HA, which could aid to avoiding the overestimation of potential risk of GFMs in natural aquatic environment.

Global gene expression analysis of macrophage response induced by nonporous and porous silica nanoparticles

Little is known about the global gene expression profile of macrophages in response to changes in size and porosity of silica nanoparticles (SNPs). Spherical nonporous SNPs of two different diameters, and mesoporous spherical SNPs with comparable size were characterized. Reactive oxygen species, mitochondrial membrane potential, lysosome degradation capacity, and lysosome pH were measured to evaluate the influence of nonporous and mesoporous SNPs on mitochondrial and lysosomal function. RNA-sequencing was utilized to generate transcriptional profiles of RAW264.7 macrophages exposed to non-toxic SNP doses. DESeq2, limma, and BinReg2 software were used to analyze the data based on both unsupervised and supervised strategies to identify genes with greatest differences among NP treatments. Utilizing GATHER and DAVID software, possible induced pathways were studied. We found that mesoporous silica nanoparticles are capable of altering gene expression in macrophages at doses that do not elicit acute cytotoxicity, while gene transcription was minimally affected by nonporous SNPs.

Toxicogenomics: A New Paradigm for Nanotoxicity Evaluation

The wider applications of nanoparticles (NPs) has evoked a world-wide concern due to their possible risk of toxicity in humans and other organisms. Aggregation and accumulation of NPs into cell leads to their interaction with biological macromolecules including proteins, nucleic acids and cellular organelles, which eventually induce toxicological effects. Application of toxicogenomics to investigate molecular pathway-based toxicological consequences has opened new vistas in nanotoxicology research. Indeed, genomic approaches appeared as a new paradigm in terms of providing information at molecular levels and have been proven to be as a powerful tool for identification and quantification of global shifts in gene expression. Toxicological responses of NPs have been discussed in this chapter with the aim to provide a clear understanding of the molecular mechanism of NPs induced toxicity both in in vivo and in vitro test models.

Enhanced cell uptake of fluorescent drug-loaded nanoparticles via an implantable photothermal fibrous patch for more effective cancer cell killing

Great efforts have been devoted to effective delivery of therapeutics into cells for cancer therapy. The exploration of nanoparticle based drug delivery systems (DDSs) faces daunting challenges in low efficacy of intracellular delivery. Herein, a localized drug delivery device consisting of photoluminescent mesoporous silica nanoparticles (PLMSNs) and photothermal fibrous matrix was investigated. Specifically, PLMSNs modified with a pH-sensitive polydopamine (PDA) 'gatekeeper' served as a doxorubicin (DOX) carrier and could release DOX once the PLMSNs were up-taken by the cancer cells. The PLMSNs were electrostatically assembled on the surface of electrospun biodegradable poly(ε-caprolactone)/gelatin fibrous mesh incorporated with photothermal carbon nanoparticles (CNPs), leading to an implantable patch used as localized delivery platform. Comparing to free particulate DDSs, this implantable composite patch device was found to significantly enable superior cell up-taking effect and consequently enhance in-vitro therapeutic efficacy against tumor cells. Namely, under near infrared irradiation, the photothermal effect of CNPs in the implantable patch weakens the electrostatic interaction between the PLMSNs and poly(ε-caprolactone)/gelatin/CNP fibrous mesh, resulting in the controlled release of the PLMSNs and subsequent internalization into the tumor cells for more effective cancer cell killing. This implantable therapeutic device may therefore inspire another way of developing localized cancer therapy.

Black TiO2 based core-shell nanocomposites as doxorubicin carriers for thermal imaging guided synergistic therapy of breast cancer

TiO₂ nanomaterials have been widely used for anticancer drug carriers and UV/980 nm NIR triggered cancer synergistic platforms. However, traditional pure TiO₂ nanocarriers encounter some serious drawbacks, such as low drug loading ability, limited tissue penetration of UV light, and heating effect of 980 nm NIR on normal tissue, which obstruct their further application in cancer treatment. To overcome those challenges, novel mesoporous silica (mSiO₂) coated black TiO₂ core-shell nanocomposites are designed and constructed as doxorubicin carriers for 808 nm NIR triggered thermal imaging guided photothermal therapy combined chemotherapy of breast cancer. Properties of the nanocomposites such as micro-morphology, size, drug loading ability and release, targeting performance, and therapy efficiency in vitro and in vivo were evaluated. The results indicated the core-shell nanocomposites with dramatically increased loading ability were pH-responsive/NIR-accelerated doxorubicin release nanocarriers and showed synergistic breast cancer treatment in vitro and in vivo. This study verifies that the newly prepared mSiO₂ coated black TiO₂ core-shell nanocarriers can overcome the limitations of traditional TiO₂ nanocarriers and thus improve and broaden usage of TiO₂ nanoparticles in nanomedicine.

Functionalization of mesoporous organosilica nanocarrier for pH/glutathione dual-responsive drug delivery and imaging of cancer therapy process

A multifunctional drug nanocarrier is developed by incorporating acetaldehyde-modified-cystine (AMC) into mesoporous organosilica nanoparticles (MONs), shortly termed as MONs-AMC. The anticancer drug doxorubicin (DOX) links directly to MONs-AMC through electrostatic interaction between DOX and AMC to produce a conjugate, MONs-AMC-DOX, with a drug loading efficiency of 26.24 ± 1.35%, corresponding to a loading capacity of 0.26 ± 0.01mgmg^-1 for DOX. Schiff base AMC contains a -S-S- bond and two -C˭N- bonds which cleave in the presence of certain level of GSH and in an acidic medium, providing MONs-AMC-DOX the capability for triggering pH and glutathione (GSH) dual-responsive drug release. Further, the self-fluorescent nature of AMC offers the tracing capability without the need of fluorescent label, which facilitates real-time tracing of the drug delivery and cancer therapy process. With 10mmolL^-1 GSH and at pH 5.0, a drug release efficiency of 52.27 ± 2.84% is achieved. The intracellular drug release process is traced with confocal laser scanning microscope by monitoring the green fluorescence of MONs-AMC-DOX and red fluorescence of DOX with excitation at 408nm and 488nm, respectively. The drug loaded nanocarriers exhibit a time-dependent cellular uptake behavior, providing an enhanced therapeutic effect to A549 cancer cells.

Molecular Elucidation of Biological Response to Mesoporous Silica Nanoparticles in Vitro and in Vivo

Biomedical applications of mesoporous silica nanoparticles (MSNs) require efficient cellular uptake and low toxicity. The purpose of this study is to investigate the cellular uptake and toxicity of MSNs with different sizes and charges (50, 100, and 250 nm with a positive surface charge and 100 nm with a negative surface charge) exposed to human monocyte-derived macrophages, lung epithelium BEAS-2B cells, and mice using genome-wide gene expression analysis and cellular/animal-level end point tests. We found that MSNs can be taken up into cells through endocytosis in a charge- and size-dependent manner, with positively charged and larger MSNs being more easily taken up into the cells by recruiting more types of endocytotic pathways for more cellular uptake. Moreover, the cytotoxicity of MSNs could be correlated with the amount of MSNs taken up by cells, which positively correlates to the particle size and dosage. Therefore, only positively charged and larger MSNs (≥100 nm) during higher treatment doses (≥500 μg mL^-1) resulted in a sufficient accumulation of internalized MSNs in cells to induce significant release of reactive oxygen species (ROS) and oxidative stress, inflammatory gene upregulation through NF-κB and AP-1, and eventually autophagy-mediated necrotic cell death. Furthermore, genome-wide gene expression analysis could reflect the above in vitro cellular damages and corresponding in vivo injuries in mice, indicating that specific gene expression footprints may be used for assessing the safety of nanoparticles. The present finding provides some insights into the rational design of effective MSN-based drug/gene delivery systems and biomedical applications.

Size-dependent cellular uptake mechanism and cytotoxicity toward calcium oxalate on Vero cells

Urinary crystals with various sizes are present in healthy individuals and patients with kidney stone; however, the cellular uptake mechanism of calcium oxalate of various sizes has not been elucidated. This study aims to compare the internalization of nano-/micron-sized (50 nm, 100 nm, and 1 μm) calcium oxalate monohydrate (COM) and dihydrate (COD) crystals in African green monkey renal epithelial (Vero) cells. The internalization and adhesion of COM and COD crystals to Vero cells were enhanced with decreasing crystal size. Cell death rate was positively related to the amount of adhered and internalized crystals and exhibited higher correlation with internalization than that with adhesion. Vero cells mainly internalized nano-sized COM and COD crystals through clathrin-mediated pathways as well as micron-sized crystals through macropinocytosis. The internalized COM and COD crystals were distributed in the lysosomes and destroyed lysosomal integrity to some extent. The results of this study indicated that the size of crystal affected cellular uptake mechanism, and may provide an enlightenment for finding potential inhibitors of crystal uptake, thereby decreasing cell injury and the occurrence of kidney stones.

Facile scalable synthesis of highly monodisperse small silica nanoparticles using alkaline buffer solution and their application for efficient sentinel lymph node mapping

Cancer nanomedicine involving nanotechnology-based drugs and in vivo imaging agents is an active field of nanoscience that provides new ways of enhancing therapeutic and diagnostic efficacy.

Design and cellular studies of a carbon nanotube-based delivery system for a hybrid platinum-acridine anticancer agent

A three-component drug-delivery system has been developed consisting of multi-walled carbon nanotubes (MWCNTs) coated with a non-classical platinum chemotherapeutic agent ([PtCl(NH3)2(L)]Cl (P3A1; L=N-(2-(acridin-9-ylamino)ethyl)-N-methylproprionimidamide) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-5000] (DSPE-mPEG). The optimized P3A1-MWCNTs are colloidally stable in physiological solution and deliver more P3A1 into breast cancer cells than treatment with the free drug. Furthermore, P3A1-MWCNTs are cytotoxic to several cell models of breast cancer and induce S-phase cell cycle arrest and non-apoptotic cell death in breast cancer cells. By contrast, free P3A1 induces apoptosis and allows progression to G2/M phase. Photothermal activation of P3A1-MWCNTs to generate mild hyperthermia potentiates their cytotoxicity. These findings suggest that delivery of P3A1 to cancer cells using MWCNTs as a drug carrier may be beneficial for combination cancer chemotherapy and photothermal therapy.

Inorganic Nanocarriers Overcoming Multidrug Resistance for Cancer Theranostics

Cancer multidrug resistance (MDR) could lead to therapeutic failure of chemotherapy and radiotherapy, and has become one of the main obstacles to successful cancer treatment. Some advanced drug delivery platforms, such as inorganic nanocarriers, demonstrate a high potential for cancer theranostic to overcome the cancer-specific limitation of conventional low-molecular-weight anticancer agents and imaging probes. Specifically, it could achieve synergetic therapeutic effects, demonstrating stronger killing effects to MDR cancer cells by combining the inorganic nanocarriers with other treatment manners, such as RNA interference and thermal therapy. Moreover, the inorganic nanocarriers could provide imaging functions to help monitor treatment responses, e.g., drug resistance and therapeutic effects, as well as analyze the mechanism of MDR by molecular imaging modalities. In this review, the mechanisms involved in cancer MDR and recent advances of applying inorganic nanocarriers for MDR cancer imaging and therapy are summarized. The inorganic nanocarriers may circumvent cancer MDR for effective therapy and provide a way to track the therapeutic processes for real-time molecular imaging, demonstrating high performance in studying the interaction of nanocarriers and MDR cancer cells/tissues in laboratory study and further shedding light on elaborate design of nanocarriers that could overcome MDR for clinical translation.

Oxidative stress-induced toxicity of CuO nanoparticles and related toxicogenomic responses in Arabidopsis thaliana

Microarray analysis of toxicogenomic effects of CuO NPs on Arabidopsis thaliana was conducted. Arabidopsis growth was significantly inhibited by CuO NPs (10 and 20 mg/L). CuO NPs (10 and 20 mg/L) caused significant root damage after short-time (0-2 h) exposure while their corresponding Cu(2+) ions (0.80 and 1.35 mg/L) did not show any root damage. After longer exposure times (1 and 2 days), Cu(2+) ions induced obvious root damage, indicating that released Cu(2+) ions from CuO NPs contributed partial toxicity during CuO NPs exposure. After CuO NPs (10 mg/L) exposure for 2 h, reactive oxygen species (ROS) generation in root tips was much higher than that in the corresponding Cu(2+) ions (0.8 mg/L) treatment. The gene ontology categories identified from microarray analysis showed that CuO NPs (10 mg/L) caused 1658 differentially expressed genes (p < 0.01, fold change>3). Of these, 1035 and 623 genes were up-regulated and down-regulated, respectively. 47 genes among all the up-regulated genes were response to oxidative stress, in which 19 genes were also related to "response to abiotic stimulus" and 12 genes were involved in the phenylpropanoid biosynthesis of the KEGG metabolic pathway. The expression of all the selected genes (RHL41, MSRB7, BCB, PRXCA, and MC8) measured using quantitative RT-PCR was consistent with the microarray analysis. CuO NPs contributed much stronger up-regulation of oxidative stress-related genes than the corresponding Cu(2+) ions.

Copper-doped mesoporous silica nanospheres, a promising immunomodulatory agent for inducing osteogenesis

The application of mesoporous silica nanospheres (MSNs) loaded with drugs/growth factors to induce osteogenic differentiation of stem cells has been trialed by a number of researchers recently. However, limitations such as high cost, complex fabrication and unintended side effects from supraphysiological concentrations of the drugs/growth factors represent major obstacles to any potential clinical application in the near term. In this study we reported an in situ one-pot synthesis strategy of MSNs doped with hypoxia-inducing copper ions and systematically evaluated the nanospheres by in vitro biological assessments. The Cu-containing mesoporous silica nanospheres (Cu-MSNs) had uniform spherical morphology (∼100nm), ordered mesoporous channels (∼2nm) and homogeneous Cu distribution. Cu-MSNs demonstrated sustained release of both silicon (Si) and Cu ions and controlled degradability. The Cu-MSNs were phagocytized by immune cells and appeared to modulate a favorable immune environment by initiating proper pro-inflammatory cytokines, inducing osteogenic/angiogenic factors and suppressing osteoclastogenic factors by the immune cells. The immune microenvironment induced by the Cu-MSNs led to robust osteogenic differentiation of bone mesenchymal stem cells (BMSCs) via the activation of Oncostation M (OSM) pathway. These results suggest that the novel Cu-MSNs could be used as an immunomodulatory agent with osteostimulatory capacity for bone regeneration/therapy application.

STATEMENT OF SIGNIFICANCE

In order to stimulate both osteogenesis and angiogenesis of stem cells for further bone regeneration, a new kind of hypoxia-inducing copper doped mesoporous silica nanospheres (Cu-MSNs) were prepared via one-pot synthesis. Biological assessments under immune environment which better reflect the in vivo response revealed that the nanospheres possessed osteostimulatory capacity and had potential as immunomodulatory agent for bone regeneration/therapy application. The strategy of introducing controllable amount of therapeutic ions instead of loading expensive drugs/growth factors in mesoporous silica nanosphere provides new options for bioactive nanomaterial functionalization.

Multifunctional magnetic silica nanotubes for MR imaging and targeted drug delivery

A multifunctional drug delivery vehicle consisting of a tubular shaped silica host, a compact superparamagnetic iron oxide nanoparticle layer and a hyaluronic acid surface coating was developed as a theranostic platform, for in vivo MR imaging and magnetically guided/cancer targeted drug delivery.

Mitigation in Multiple Effects of Graphene Oxide Toxicity in Zebrafish Embryogenesis Driven by Humic Acid

Graphene oxide (GO) is a widely used carbonaceous nanomaterial. To date, the influence of natural organic matter (NOM) on GO toxicity in aquatic vertebrates has not been reported. During zebrafish embryogenesis, GO induced a significant hatching delay and cardiac edema. The intensive interactions of GO with the chorion induces damage to chorion protuberances, excessive generation of (•)OH, and changes in protein secondary structure. In contrast, humic acid (HA), a ubiquitous form of NOM, significantly relieved the above adverse effects. HA reduced the interactions between GO and the chorion and mitigated chorion damage by regulating the morphology, structures, and surface negative charges of GO. HA also altered the uptake and deposition of GO and decreased the aggregation of GO in embryonic yolk cells and deep layer cells. Furthermore, HA mitigated the mitochondrial damage and oxidative stress induced by GO. This work reveals a feasible antidotal mechanism for GO in the presence of NOM and avoids overestimating the risks of GO in the natural environment.

Stimulation of osteogenesis and angiogenesis of hBMSCs by delivering Si ions and functional drug from mesoporous silica nanospheres

Multifunctional bioactive materials with the ability to stimulate osteogenesis and angiogenesis of stem cells play an important role in the regeneration of bone defects. However, how to develop such biomaterials remains a significant challenge. In this study, we prepared mesoporous silica nanospheres (MSNs) with uniform sphere size (∼90 nm) and mesopores (∼2.7 nm), which could release silicon ions (Si) to stimulate the osteogenic differentiation of human bone marrow stromal cells (hBMSCs) via activating their ALP activity, bone-related gene and protein (OCN, RUNX2 and OPN) expression. Hypoxia-inducing therapeutic drug, dimethyloxaloylglycine (DMOG), was effectively loaded in the mesopores of MSNs (D-MSNs). The sustained release of DMOG from D-MSNs could stabilize HIF-1α and further stimulated the angiogenic differentiation of hBMSCs as indicated by the enhanced VEGF secretion and protein expression. Our study revealed that D-MSNs could combine the stimulatory effect on both osteogenic and angiogenic activity of hBMSCs. The potential mechanism of D-MSN-stimulated osteogenesis and angiogenesis was further elucidated by the supplementation of cell culture medium with pure Si ions and DMOG. Considering the easy handling characteristics of nanospheres, the prepared D-MSNs may be applied in the forms of injectable spheres for minimally invasive surgery, or MSNs/polymer composite scaffolds for bone defect repair. The concept of delivering both stimulatory ions and functional drugs may offer a new strategy to construct a multifunctional biomaterial system for bone tissue regeneration.

Mitochondria-targeting nanoplatform with fluorescent carbon dots for long time imaging and magnetic field-enhanced cellular uptake

In this study, a biocompatible nanoplatform has been constructed on the basis of magnetic mesoporous silica nanoparticles (Fe3O4@mSiO2) via surface modification of triphenylphospine (TPP) and then conjugation with fluorescent carbon dots (CDs). The as-prepared Fe3O4@mSiO2-TPP/CDs nanoplatform shows a very low cytotoxicity and apoptosis rate in various cell lines such as A549, CHO, HeLa, SH-SY5Y, HFF, and HMEC-1. More importantly, this nanoplatform integrates long time cell imaging, mitochondria-targeting, and magnetic field-enhanced cellular uptake functionalities into an all-in-one system. Time-dependent mitochondrial colocalization in all of the cell lines has been proved by using confocal laser scanning microscopy and flow cytometry, while the multicolored fluorescence of the Fe3O4@mSiO2-TPP/CDs could remain bright and stable after coincubation for 24 h. In addition, the cellular uptake efficiency could be enhanced in a short time as a static magnetic field of 0.30 T was applied to the coincubation system of A549 and HFF cell lines. This bionanoplatform may have potential applications in targeted drug delivery for mitochondria diseases as well as early cancer diagnosis and treatment.

Structure regulation of silica nanotubes and their adsorption behaviors for heavy metal ions: pH effect, kinetics, isotherms and mechanism

Silica nanotubes (SNTs) with controlled nanotubular structure were synthesized via an electrospinning and calcination process. In this regard, SNTs were found to be ideal adsorbents for Pb(II) removal with a higher adsorption capacity, and surface modification of the SNTs by sym-diphenylcarbazide (SD-SNTs) markedly enhanced the adsorption ability due to the chelating interaction between imino groups and Pb(II). The pH effect, kinetics, isotherms and adsorption mechanism of SNTs and SD-SNTs on Pb(II) adsorption were investigated and discussed detailedly. The adsorption capacity for Pb(II) removal was found to be significantly improved with the decrease of pH value. The Langmuir adsorption model agreed well with the experimental data. As for kinetic study, the adsorption onto SNTs and SD-SNTs could be fitted to pseudo-first-order and pseudo-second-order model, respectively. In addition, the as-prepared SNTs and SD-SNTs also exhibit high adsorption ability for Cd(II) and Co(II). The experimental results demonstrate that the SNTs and SD-SNTs are potential adsorbents and can be used effectively for the treatment of heavy-metal-ions-containing wastewater.

Next-generation sequencing reveals low-dose effects of cationic dendrimers in primary human bronchial epithelial cells

Gene expression profiling has developed rapidly in recent years with the advent of deep sequencing technologies such as RNA sequencing (RNA Seq) and could be harnessed to predict and define mechanisms of toxicity of chemicals and nanomaterials. However, the full potential of these technologies in (nano)toxicology is yet to be realized. Here, we show that systems biology approaches can uncover mechanisms underlying cellular responses to nanomaterials. Using RNA Seq and computational approaches, we found that cationic poly(amidoamine) dendrimers (PAMAM-NH2) are capable of triggering down-regulation of cell-cycle-related genes in primary human bronchial epithelial cells at doses that do not elicit acute cytotoxicity, as demonstrated using conventional cell viability assays, while gene transcription was not affected by neutral PAMAM-OH dendrimers. The PAMAMs were internalized in an active manner by lung cells and localized mainly in lysosomes; amine-terminated dendrimers were internalized more efficiently when compared to the hydroxyl-terminated dendrimers. Upstream regulator analysis implicated NF-κB as a putative transcriptional regulator, and subsequent cell-based assays confirmed that PAMAM-NH2 caused NF-κB-dependent cell cycle arrest. However, PAMAM-NH2 did not affect cell cycle progression in the human A549 adenocarcinoma cell line. These results demonstrate the feasibility of applying systems biology approaches to predict cellular responses to nanomaterials and highlight the importance of using relevant (primary) cell models.

Effects of an 11-nm DMSA-coated iron nanoparticle on the gene expression profile of two human cell lines, THP-1 and HepG2

Background

Iron nanoparticles (FeNPs) have attracted increasing attention over the past two decades owing to their promising application as biomedical agents. However, to ensure safe application, their potential nanotoxicity should be carefully and thoroughly evaluated. Studies on the effects of FeNPs on cells at the transcriptomic level will be helpful for identifying any potential nanotoxicity of FeNPs and providing valuable mechanistic insights into various FeNPs-induced nanotoxicities.

Results

This study investigated the effects of an 11-nm dimercaptosuccinic acid-coated magnetite nanoparticle on the gene expression profiles of two human cell lines, THP-1 and HepG2. It was found that the expression of hundreds of genes was significantly changed by a 24-h treatment with the nanoparticles at two doses, 50 μg/mL and 100 μg/mL, in the two cell types. By identifying the differentially expressed genes and annotating their functions, this study characterized the general and cell-specific effects of the nanoparticles on two cell types at the gene, biological process and pathway levels. At these doses, the overall effects of the nanoparticle on the THP-1 cells were the induction of various responses and repression of protein translation, but in the HepG2 cells, the main effects were the promotion of cell metabolism, growth and mobility. In combination with a previous study, this study also characterized the common genes, biological processes and pathways affected by the nanoparticle in two human and mouse cell lines and identified Id3 as a nanotoxicity biomarker of the nanoparticle.

Conclusion

The studied FeNPs exerted significant effects on the gene expression profiles of human cells. These effects were highly dependent on the innate biological functions of cells, i.e., the cell types. However, cells can also show some cell type-independent effects such as repression of Id3 expression. Id3 can be used as a nanotoxicity biomarker for iron nanoparticles.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-014-0063-3) contains supplementary material, which is available to authorized users.

Insights into the distinguishing stress-induced cytotoxicity of chiral gold nanoclusters and the relationship with GSTP1

Chiral gold nanoclusters (Au NCs) exhibit attracting properties owing to their unique physical and chemical properties. Herein we report for the first time chiral gold nanoclusters' cytotoxicity and potential molecular mechanism. The L-glutathione (i.e. L-GSH) and D-glutathione (i.e. D-GSH)-capped Au NCs were prepared and characterized by HRTEM, UV-vis, photoluminescence and circular dichroism (CD) spectroscopy. Results showed that the CD spectra of L-glutathione (i.e. L-GSH) and D-glutathione (i.e. D-GSH)-capped Au NCs exhibited multiple bands which were identically mirror-imaged, demonstrating that the chirality of GSH-capped NCs had contributions from both the metal core and the ligand. The effects of AuNCs@L-GSH and AuNCs@D-GSH on cells were similar based on the cell physiology related cytotoxicity, although the effects became more prominent in AuNCs@D-GSH treated cells, including ROS generation, mitochondrial membrane depolarization, cell cycle arrest and apoptosis. Global gene expression and pathway analysis displayed that both AuNCs@L-GSH and AuNCs@D-GSH caused the up-regulation of genes involved in cellular rescue and stress response, while AuNCs@D-GSH individually induced up-regulation of transcripts involved in some metabolic- and biosynthetic-related response. MGC-803 cells were more sensitive to the oxidative stress damage induced by chiral Au NCs than GES-1 cells, which was associated with GSTP1 hypermethylation. In conclusion, chiral gold nanoclusters exhibit this chirality-associated regulation of cytotoxicity, different gene expression profiling and epigenetic changes should be responsible for observed phenomena. Our study highlights the importance of the interplays between chiral materials and biological system at sub-nano level.