Novel metal peroxide nanoboxes restrain Clostridioides difficile infection beyond the bactericidal and sporicidal activity.

Clostridioides difficile spores are considered as the major source responsible for the development of C. difficile infection (CDI), which is associated with an increased risk of death in patients and has become an important issue in infection control of nosocomial infections. Current treatment against CDI still relies on antibiotics, which also damage normal flora and increase the risk of CDI recurrence. Therefore, alternative therapies that are more effective against C. difficile bacteria and spores are urgently needed. Here, we designed an oxidation process using H2O2 containing PBS solution to generate Cl- and peroxide molecules that further process Ag and Au ions to form nanoboxes with Ag-Au peroxide coat covering Au shell and AgCl core (AgAu-based nanoboxes). The AgAu-based nanoboxes efficiently disrupted the membrane structure of bacteria/spores of C. difficile after 30-45 min exposure to the highly reactive Ag/Au peroxide surface of the nano structures. The Au-enclosed AgCl provided sustained suppression of the growth of 2 × 107 pathogenic Escherichia coli for up to 19 days. In a fecal bench ex vivo test and in vivo CDI murine model, biocompatibility and therapeutic efficacy of the AuAg nanoboxes to attenuate CDI was demonstrated by restoring the gut microbiota and colon mucosal structure. The treatment successfully rescued the CDI mice from death and prevented their recurrence mediated by vancomycin treatment. The significant outcomes indicated that the new peroxide-derived AgAu-based nanoboxes possess great potential for future translation into clinical application as a new alternative therapeutic strategy against CDI.

The Application of an Extracellular Vesicle-Based Biosensor in Early Diagnosis and Prediction of Chemoresponsiveness in Ovarian Cancer.

BACKGROUND: Ovarian cancer (OVCA) is the most fatal gynecological cancer with late diagnosis and plasma gelsolin (pGSN)-mediated chemoresistance representing the main obstacles to treatment success. Since there is no reliable approach to diagnosing patients at an early stage as well as predicting chemoresponsiveness, there is an urgent need to develop a diagnostic platform for such purposes. Small extracellular vesicles (sEVs) are attractive biomarkers given their potential accuracy for targeting tumor sites. METHODS: We have developed a novel biosensor which utilizes cysteine-functionalized gold nanoparticles that simultaneously bind to cisplatin (CDDP) and plasma/cell-derived EVs, affording us the advantage of predicting OVCA chemoresponsiveness, and early diagnosis using surface-enhanced Raman spectroscopy. RESULTS: We found that pGSN regulates cortactin (CTTN) content resulting in the formation of nuclear- and cytoplasmic-dense granules facilitating the secretion of sEVs carrying CDDP; a strategy used by resistant cells to survive CDDP action. The clinical utility of the biosensor was tested and subsequently revealed that the sEV/CA125 ratio outperformed CA125 and sEV individually in predicting early stage, chemoresistance, residual disease, tumor recurrence, and patient survival. CONCLUSION: These findings highlight pGSN as a potential therapeutic target and provide a potential diagnostic platform to detect OVCA earlier and predict chemoresistance; an intervention that will positively impact patient-survival outcomes.

ROS-generating alginate-coated gold nanorods as biocompatible nanosonosensitisers for effective sonodynamic therapy of cancer.

Sonodynamic therapy (SDT) emerges as a promising non-invasive alternative for eradicating malignant tumours. However, its therapeutic efficacy remains limited due to the lack of sonosensitisers with high potency and biosafety. Previously, gold nanorods (AuNRs) have been extensively studied for their applications in photodynamic or photothermal cancer therapy, but their sonosensitising properties are largely unexplored. Here, we reported the applicability of alginate-coated AuNRs (AuNRsALG) with improved biocompatibility profiles as promising nanosonosensitisers for SDT for the first time. AuNRsALG were found stable under ultrasound irradiation (1.0 W/cm2, 5 min) and maintained structural integrity for 3 cycles of irradiation. The exposure of the AuNRsALG to ultrasound irradiation (1.0 W/cm2, 5 min) was shown to enhance the cavitation effect significantly and generate a 3 to 8-fold higher amount of singlet oxygen (1O2) than other reported commercial titanium dioxide nanosonosensitisers. AuNRsALG exerted dose-dependent sonotoxicity on human MDA-MB-231 breast cancer cells in vitro, with âˆ¼ 81% cancer cell killing efficacy at a sub-nanomolar level (IC50 was 0.68 nM) predominantly through apoptosis. The protein expression analysis showed significant DNA damage and downregulation of anti-apoptotic Bcl-2, suggesting AuNRsALG induced cell death through the mitochondrial pathway. The addition of mannitol, a reactive oxygen species (ROS) scavenger, inhibited cancer-killing effect of AuNRsALG-mediated SDT, further verifying that the sonotoxicity of AuNRsALG is driven by the production of ROS. Overall, these results highlight the potential application of AuNRsALG as an effective nanosonosensitising agent in clinical settings.

Mammalian tooth enamel functional sophistication demonstrated by combined nanotribology and synchrotron radiation FTIR analyses.

The teeth of limbed vertebrates used for capturing and processing food are composed of mineralized dentine covered by hypermineralized enamel, the hardest material organisms produce. Here, we combine scanning probe microscopy, depth sensing, and spectromicroscopy (SR-FTIR) to characterize the surface ultrastructural topography, nanotribology, and chemical compositions of mammal species with different dietary habits, including omnivorous humans. Our synergistic approach shows that enamel with greater surface hardness or thickness exhibited a more salient gradient feature from the tooth surface to the dentino-enamel junction (DEJ) one that corresponds to the in situ phosphate-to-amide ratio. This gradient feature of enamel covering softer dentine is the determining factor of the amazingly robust physical property of this unique biomaterial. It provides the ability to dissipate stress under loading and prevent mechanical failure. Evolutionary change in the biochemical composition and biomechanical properties of mammalian dentition is related to variations in the oral processing of different food materials.

Acidic Microenvironment-Sensitive Core-Shell Microcubes: The Self-assembled and the Therapeutic Effects for Caries Prevention.

OBJECTIVES: The aim of this study was to develop a new material with integrated interface design that could achieve the purpose of environmental-sensing controlled release against cariogenic bacteria. Furthermore, this material can rebalance oral flora and serve as a preventive and reparative measure of dental caries. MATERIALS AND METHODS: NaF@PAA@HA@polyelectrolytes@HA@PAA particles were synthesized using the method of two-solution phases precipitation followed by biocompatible polymers coating layer by layer. The structure of the particles was confirmed by transmission electron microscope. The fluoride release profile was measured by fluoride ion electrode. Antimicrobial activity against the cariogenic microorganisms was analyzed by scanning electron microscopy and energy dispersive spectrum. The efficacy experiments were conducted on tooth enamel slides to evaluated fluoride absorption and antibacterial activity of the prototype toothpaste containing microcube particles RESULTS: The structure of NaF@PAA@HA@polyelectrolytes@HA@PAA particles showed a core surrounded by tooth-adhesion polymer layers in thin fin or filament structure. The loaded concentration of fluoride in the particles' core was 148,996 ± 28,484 ppm. NaF@PAA@HA@polyelectrolytes@HA@PAA particles showed selective inhibition of cariogenic microorganisms over probiotic strains and stronger fluoride adhesion on tooth enamel. A burst release (over 80%) of fluoride from the particle-containing toothpaste was observed under cariogenic acidic environment (pH < 5), while it remained extremely low under neutral environment. Compared with the best results of commercial toothpastes, our prototype toothpaste increased enamel fluoride uptake by 8-fold in normal enamel slides and by 11-fold in the slides with induced white spot lesions after either 1- or 7-day treatment. The prototype toothpaste also showed better inhibition of cariogenic microorganisms than the commercial brands. The coverage area of cariogenic bacteria under our toothpaste treatment was 73% on normal enamel slides compared with the commercial brands, while it was 69% in the induced white spot lesions. CONCLUSIONS: In our study, an intelligent toothpaste was developed that selectively inhibits cariogenic bacteria by microenvironment proton-triggered fluoride release. Such novel design would accomplish a favorable flora balance for optimal long-term oral health.

Dysregulation of SOX17/NRF2 axis confers chemoradiotherapy resistance and emerges as a novel therapeutic target in esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is the sixth leading cause of cancer-associated death worldwide with a dismal overall 5-year survival rate of less than 20%. The standard first-line therapy for advanced ESCC is concomitant chemo-radiation therapy (CCRT); however, patients usually develop resistance, resulting in unfavorable outcomes. Therefore, it is urgent to identify the mechanisms underlying CCRT resistance and develop effective treatment strategies. METHODS: Patients' endoscopic biopsy tumor tissues obtained before CCRT treatment were used to perform RNA-seq and GSEA analysis. Immunohistochemical (IHC) staining, chromatin immunoprecipitation (ChIP), and promoter reporter analyses were conducted to investigate the relationship between SOX17 and NRF2. Xenograft mouse models were used to study the role of SOX17/NRF2 axis in tumor growth and the efficacy of carboxymethyl cellulose-coated zero-valent-iron (ZVI@CMC). RESULTS: In this study, a notable gene expression signature associated with NRF2 activation was observed in the poor CCRT responders. Further, IHC staining of endoscopic biopsy of 164 ESCC patients revealed an inverse correlation between NRF2 and SOX17, a tumor-suppressive transcription factor with low expression in ESCC due to promoter hypermethylation. Using ChIP and promoter reporter analyses, we demonstrated that SOX17 was a novel upstream transcriptional suppressor of NRF2. In particular, SOX17low/NRF2high nuclear level significantly correlated with poor CCRT response and poor survival, indicating that the dysregulation of SOX17/NRF2 axis played a pivotal role in CCRT resistance and tumor progression. Notably, the in-house developed nanoparticle ZVI@CMC functioned as an inhibitor of DNA methyltransferases to restore expression of SOX17 that downregulated NRF2, thereby overcoming the resistance in ESCC. Additionally, the combination of ZVI@CMC with radiation treatment significantly augmented anticancer efficacy to inhibit tumor growth in CCRT resistant cancer. CONCLUSION: This study identifies a novel SOX17low/NRF2high signature in ESCC patients with poor prognosis, recognizes SOX17 as a transcriptional repressor of NRF2, and provides a promising strategy targeting SOX17/NRF2 axis to overcome resistance.

Prohibitin 1 interacts with p53 in the regulation of mitochondrial dynamics and chemoresistance in gynecologic cancers.

BACKGROUND: Mitochondrial dynamics (e.g. fission/fusion) play an important role in controlling chemoresistance in representative gynecologic malignancies, ovarian and cervical cancer. Processing the long form of Optic atrophy (L-Opa)1 is a distinctive character of mitochondrial fragmentation, associated with chemosensitivity. Here, we examined the role of prohibitin (Phb)1 in increasing L-Opa1 processing via the regulating mitochondrial protease, Oma1 and its direct interaction with p-p53 (ser15) and pro-apoptotic Bcl-2 antagonist/killer (Bak) 1 in the signaling axis and if this phenomenon is associated with prognosis of patients. METHODS: We compared Cisplatin (CDDP)-induced response of mitochondrial dynamics, molecular interaction among p-p53 (ser15)-Phb1-Bak, and chemoresponsiveness in paired chemosensitive and chemoresistant gynecologic cancer cells (ovarian and cervical cancer cell lines) using western blot, immunoprecipitation, sea horse, and immunofluorescence. Translational strategy with proximity ligation assessment in phb1-p-p53 (ser15) in human ovarian tumor sections further confirmed in vitro finding, associated with clinical outcome. RESULTS: We report that: (1) Knock-down of Phb1 prevents Cisplatin (cis-diamine-dichloroplatinum; CDDP) -induced changes in mitochondrial fragmentation and Oma1 mediated cleavage, and Opa1 processing; (2) In response to CDDP, Phb1 facilitates the p-p53 (ser15)-Phb1-Bak interaction in mitochondria in chemosensitive gynecologic cancer cells but not in chemoresistant cells; (3) Akt overexpression results in suppressed p-p53(Ser15)-Phb1 interaction and dysregulated mitochondrial dynamics, and (4) Consistent with in vitro findings, proximity ligation assessment (PLA) in human ovarian tumor sections demonstrated that p-p53(ser15)-Phb1-Bak interaction in mitochondria is associated with better chemoresponsiveness and clinical outcome of patients. Determining the molecular mechanisms by which Phb1 facilitates mitochondrial fragmentation and interacts with p53 may advance the current understanding of chemoresistance and pathogenesis of gynecologic cancer. CONCLUSION: Determining the key molecular mechanisms by which Phb1 facilitates the formation of p-p53 (ser15)-Bak-Phb1 and its involvement in the regulation of mitochondrial dynamics and apoptosis may ultimately contribute to the current understanding of molecular and cellular basis of chemoresistance in this gynecologic cancer.

From Microenvironment Remediation to Novel Anti-Cancer Strategy: The Emergence of Zero Valent Iron Nanoparticles.

Accumulated studies indicate that zero-valent iron (ZVI) nanoparticles demonstrate endogenous cancer-selective cytotoxicity, without any external electric field, lights, or energy, while sparing healthy non-cancerous cells in vitro and in vivo. The anti-cancer activity of ZVI-based nanoparticles was anti-proportional to the oxidative status of the materials, which indicates that the elemental iron is crucial for the observed cancer selectivity. In this thematic article, distinctive endogenous anti-cancer mechanisms of ZVI-related nanomaterials at the cellular and molecular levels are reviewed, including the related gene modulating profile in vitro and in vivo. From a material science perspective, the underlying mechanisms are also analyzed. In summary, ZVI-based nanomaterials demonstrated prominent potential in precision medicine to modulate both programmed cell death of cancer cells, as well as the tumor microenvironment. We believe that this will inspire advanced anti-cancer therapy in the future.

The Pathophysiologic Role of Gelsolin in Chronic Kidney Disease: Focus on Podocytes.

Chronic kidney disease (CKD) is normally related to proteinuria, a common finding in a compromised glomerular filtration barrier (GFB). GFB is a structure composed of glomerular endothelial cells, the basement membrane, and the podocytes. CKD with podocyte damage may be associated with actin cytoskeleton reorganization, resulting in podocyte effacement. Gelsolin plays a critical role in several diseases, including cardiovascular diseases and cancer. Our current study aimed to determine the connection between gelsolin and podocyte, and thus the mechanism underlying podocyte injury in CKD. Experiments were carried out on Drosophila to demonstrate whether gelsolin had a physiological role in maintaining podocyte. Furthermore, the survival rate of gelsolin-knocked down Drosophila larvae was extensively reduced after AgNO3 exposure. Secondly, the in vitro podocytes treated with puromycin aminonucleoside (PAN) enhanced the gelsolin protein expression, as well as small GTPase RhoA and Rac1, which also regulated actin dynamic expression incrementally with the PAN concentrations. Thirdly, we further demonstrated in vivo that GSN was highly expressed inside the glomeruli with mitochondrial dysfunction in a CKD mouse model. Our findings suggest that an excess of gelsolin may contribute to podocytes damage in glomeruli.

Opportunities for Nanomedicine in Clostridioides difficile Infection.

Clostridioides difficile, a spore-forming bacterium, is a nosocomial infectious pathogen which can be found in animals as well. Although various antibiotics and disinfectants were developed, C. difficile infection (CDI) remains a serious health problem. C. difficile spores have complex structures and dormant characteristics that contribute to their resistance to harsh environments, successful transmission and recurrence. C. difficile spores can germinate quickly after being exposed to bile acid and co-germinant in a suitable environment. The vegetative cells produce endospores, and the mature spores are released from the hosts for dissemination of the pathogen. Therefore, concurrent elimination of C. difficile vegetative cells and inhibition of spore germination is essential for effective control of CDI. This review focused on the molecular pathogenesis of CDI and new trends in targeting both spores and vegetative cells of this pathogen, as well as the potential contribution of nanotechnologies for the effective management of CDI.

An innovative NRF2 nano-modulator induces lung cancer ferroptosis and elicits an immunostimulatory tumor microenvironment.

Simultaneous targeting of both the tumor microenvironment and cancer cells by a single nanomedicine has not been reported to date. Here, we report the dual properties of zero-valent-iron nanoparticle (ZVI-NP) to induce cancer-specific cytotoxicity and anti-cancer immunity. Methods: Cancer-specific cytotoxicity induced by ZVI-NP was determined by MTT assay. Mitochondria functional assay, immunofluorescence staining, Western blot, RT-qPCR, and ChIP-qPCR assays were used to dissect the mechanism underlying ZVI-NP-induced ferroptotic cancer cell death. The therapeutic potential of ZVI-NP was evaluated in immunocompetent mice and humanized mice. Immune cell profiles of allografts and ex vivo cultured immune cells were examined by flow cytometry analysis, RT-qPCR assay, and immunofluorescence. Results: ZVI-NP caused mitochondria dysfunction, intracellular oxidative stress, and lipid peroxidation, leading to ferroptotic death of lung cancer cells. Degradation of NRF2 by GSK3/ß-TrCP through AMPK/mTOR activation was enhanced in such cancer-specific ferroptosis. In addition, ZVI-NP attenuated self-renewal ability of cancer and downregulated angiogenesis-related genes. Importantly, ZVI-NP augmented anti-tumor immunity by shifting pro-tumor M2 macrophages to anti-tumor M1, decreasing the population of regulatory T cells, downregulating PD-1 and CTLA4 in CD8+ T cells to potentiate their cytolytic activity against cancer cells, while attenuating PD-L1 expression in cancer cells in vitro and in tumor-bearing immunocompetent mice. In particular, ZVI-NPs preferentially accumulated in tumor and lung tissues, leading to prominent suppression of tumor growth and metastasis. Conclusions: This dual-functional nanomedicine established an effective strategy to synergistically induce ferroptotic cancer cell death and reprogram the immunosuppressive microenvironment, which highlights the potential of ZVI-NP as an advanced integrated anti-cancer strategy.

Development of flexible electrochemical impedance spectroscopy-based biosensing platform for rapid screening of SARS-CoV-2 inhibitors.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters the cells through the binding of its spike protein (S-protein) to the cell surface-expressing angiotensin-converting enzyme 2 (ACE2). Thus, inhibition of S-protein-ACE2 binding may impede SARS-CoV-2 cell entry and attenuate the progression of Coronavirus disease 2019 (COVID-19). In this study, an electrochemical impedance spectroscopy-based biosensing platform consisting of a recombinant ACE2-coated palladium nano-thin-film electrode as the core sensing element was fabricated for the screening of potential inhibitors against S-protein-ACE2 binding. The platform could detect interference of small analytes against S-protein-ACE2 binding at low analyte concentration and small volume (0.1 µg/mL and ~1 µL, estimated total analyte consumption < 4 pg) within 21 min. Thus, a few potential inhibitors of S-protein-ACE2 binding were identified. This includes (2S,3aS,6aS)-1-((S)-N-((S)-1-Carboxy-3-phenylpropyl)alanyl)tetrahydrocyclopenta[b] pyrrole-2-carboxylic acid (ramiprilat) and (2S,3aS,7aS)-1-[(2S)-2-[[(2S)-1-Carboxybutyl]amino]propanoyl]-2,3,3a,4,5,6,7,7a-octahydroindole-2-carboxylic acid (perindoprilat) that reduced the binding affinity of S-protein to ACE2 by 72% and 67%; and SARS-CoV-2 in vitro infectivity to the ACE2-expressing human oral cavity squamous carcinoma cells (OEC-M1) by 36.4 and 20.1%, respectively, compared to the PBS control. These findings demonstrated the usefulness of the developed biosensing platform for the rapid screening of modulators for S-protein-ACE2 binding.

Circulating Plasma Gelsolin: A Predictor of Favorable Clinical Outcomes in Head and Neck Cancer and Sensitive Biomarker for Early Disease Diagnosis Combined with Soluble Fas Ligand.

Head and neck cancer (HNC) accounts for more than 330,000 cancer deaths annually worldwide. Despite late diagnosis being a major factor contributing to HNC mortality, no satisfactory biomarkers exist for early disease detection. Cytoplasmic gelsolin (cGSN) was discovered to predict disease progression in HNC and other malignancies, and circulating plasma gelsolin (pGSN) levels are significantly correlated with infectious and inflammatory disease prognoses. Here, the plasma levels of five candidate biomarkers (circulating pGSN, squamous cell carcinoma antigen, cytokeratin 19 fragment, soluble Fas, and soluble Fas ligand (sFasL)) in 202 patients with HNC and 45 healthy controls were measured using enzyme-linked immunosorbent assay or Millipore cancer multiplex assay. The results demonstrated that circulating pGSN levels were significantly lower in patients with HNC than in healthy controls. Moreover, circulating pGSN outperformed other candidate biomarkers as an independent diagnostic biomarker of HNC in both sensitivity (82.7%) and specificity (95.6%). Receiver operating characteristic curves indicated that combined pGSN and sFasL levels further augmented this sensitivity (90.6%) for early disease detection. Moreover, higher pGSN levels predicted improved prognosis at both 5-year overall survival and progression-free survival. In conclusion, circulating pGSN could be an independent predictor of favorable clinical outcomes and a novel biomarker for the early HNC detection in combination with sFasL.

Silver-coated zero-valent iron nanoparticles enhance cancer therapy in mice through lysosome-dependent dual programed cell death pathways: triggering simultaneous apoptosis and autophagy only in cancerous cells.

In this study, we demonstrated that zero-valent iron (ZVI), which is widely used to remediate environmental contamination through the production of high-energy reactive oxygen species (ROS), exhibited differential cytotoxicity in cancerous cells and nonmalignant cells. Nanoparticles (NPs) with different shells exhibited distinct potencies against cancerous cells, which depended on their iron-to-oxygen ratios. Silver-coated ZVI NPs (ZVI@Ag) had the highest potency among synthesized ZVI NPs, and they simultaneously exhibited adequate biocompatibility with nonmalignant keratinocytes. The assessment of the intracellular dynamics of iron species revealed that the uptake of ZVI@Ag was similar between cancerous cells and nonmalignant cells during the first 2 h; however, only cancerous cells rapidly converted NPs into iron ions and generated large amounts of intracellular ROS, which was followed by apoptosis and autophagy induction. The aforementioned processes were prevented in the presence of iron ion chelators or by preoxidizing NPs before administration. Neutralization of lysosomal pH effectively reduced ZVI@Ag NP-induced programmed cell death. In the xenograft mouse model, cancer growth was significantly inhibited by a single dose of systematically administered NPs without significant weight loss in animals.

The exosome-mediated autocrine and paracrine actions of plasma gelsolin in ovarian cancer chemoresistance.

Ovarian cancer (OVCA) is the most lethal gynecological cancer, due predominantly to late presentation, high recurrence rate and common chemoresistance development. The expression of the actin-associated protein cytosolic gelsolin (GSN) regulates the gynecological cancer cell fate resulting in dysregulation in chemosensitivity. In this study, we report that elevated expression of plasma gelsolin (pGSN), a secreted isoform of GSN and expressed from the same GSN gene, correlates with poorer overall survival and relapse-free survival in patients with OVCA. In addition, it is highly expressed and secreted in chemoresistant OVCA cells than its chemosensitive counterparts. pGSN, secreted and transported via exosomes (Ex-pGSN), upregulates HIF1α-mediated pGSN expression in chemoresistant OVCA cells in an autocrine manner as well as confers cisplatin resistance in otherwise chemosensitive OVCA cells. These findings support our hypothesis that exosomal pGSN promotes OVCA cell survival through both autocrine and paracrine mechanisms that transform chemosensitive cells to resistant counterparts. Specifically, pGSN transported via exosomes is a determinant of chemoresistance in OVCA.

Iron Release Profile of Silica-Modified Zero-Valent Iron NPs and Their Implication in Cancer Therapy.

To evaluate the iron ion release profile of zero-valent iron (ZVI)-based nanoparticles (NPs) and their relationship with lysosomes in cancer cells, silica and mesoporous silica-coated ZVI NPs (denoted as ZVI@SiO2 and ZVI@mSiO2) were synthesized and characterized for the following study of cytotoxicity, intracellular iron ion release, and their underlying mechanisms. ZVI@mSiO2 NPs showed higher cytotoxicity than ZVI@SiO2 NPs in the OEC-M1 oral cancer cell line. In addition, internalized ZVI@mSiO2 NPs deformed into hollow and void structures within the cells after a 24-h treatment, but ZVI@SiO2 NPs remained intact after internalization. The intracellular iron ion release profile was also accordant with the structural deformation of ZVI@mSiO2 NPs. Burst iron ion release occurred in ZVI@mSiO2-treated cells within an hour with increased lysosome membrane permeability, which induced massive reactive oxygen species generation followed by necrotic and apoptotic cell death. Furthermore, inhibition of endosome-lysosome system acidification successfully compromised burst iron ion release, thereby reversing the cell fate. An in vivo test also showed a promising anticancer effect of ZVI@mSiO2 NPs without significant weight loss. In conclusion, we demonstrated the anticancer property of ZVI@mSiO2 NPs as well as the iron ion release profile in time course within cells, which is highly associated with the surface coating of ZVI NPs and lysosomal acidification.

Vancomycin-Loaded Nanoparticles Enhance Sporicidal and Antibacterial Efficacy for Clostridium difficile Infection.

Current antibiotic treatments fail to eliminate the Clostridium difficile (C. difficile) spores and induce dysbiosis and intestinal inflammation via off-target effect, which causes refractory C. difficile infection raise an unmet need for a spore-specific antimicrobial treatment. We developed a sporicidal and antimicrobial vancomycin-loaded spore-targeting iron oxide nanoparticle (van-IONP) that selectively binds to C. difficile spores. Cryo-electron microscopy showed that vancomycin-loaded nanoparticles can target and completely cover spore surfaces. They not only successfully delayed the germination of the spores but also inhibited ∼50% of vegetative cell outgrowth after 48 h of incubation. The van-IONPs also inhibited the interaction of spores with HT-29 intestinal mucosal cells in vitro. In a murine model of C. difficile infection, the van-IONP significantly protected the mice from infected by C. difficile infection, reducing intestinal inflammation, and facilitated superior mucosal viability compared with equal doses of free vancomycin. This dual-function targeted delivery therapy showed advantages over traditional therapeutics in treating C. difficile infection.

Targeted Delivery of Curcumin Rescues Endoplasmic Reticulum-Retained Mutant NOX2 Protein and Avoids Leukocyte Apoptosis.

Chronic granulomatous disease (CGD) is a primary immunodeficiency disease caused by defects in the leukocyte NADP oxidase. We previously reported that sarcoplasmic/endoplasmic reticulum calcium pump (SERCA) inhibitors could be used to rescue mutant H338Y-gp91phox protein of a particular type of CGD with a CybbC1024T mutation, leading to endoplasmic reticulum (ER) retention of the mutant protein. In this study, we developed a novel mouse model with the CybbC1024T mutation on a Cybb knockout background and investigated the therapeutic effects of ER-targeted delivery of the SERCA inhibitor, curcumin, with poly(lactic-coglycolic acid) (PLGA) nanoparticles (NPs). We found that PLGA encapsulation improved the efficacy of curcumin as a SERCA inhibitor to induce ER calcium release. ER-targeting curcumin-loaded PLGA NPs reduced and delayed extracellular calcium entry and protected the cells from mitochondrial damage and apoptosis. In vivo studies showed that ER-targeting curcumin-loaded PLGA NPs treatment enhanced neutrophil gp91phox expression, ROS production and peritoneal bacterial clearance ability of the CybbC1024T transgenic Cybb -/- mice. Our findings indicate that ER-targeted delivery of curcumin not only rescues ER-retained H338Y-gp91phox protein, and hence leukocyte function, but also enhances the bioavailability and reduces cytotoxicity. Modulation of ER function by using organelle-targeted NPs may be a promising strategy to improve the therapeutic potential of curcumin as a treatment for CGD.

Assessment of zero-valent iron-based nanotherapeutics for ferroptosis induction and resensitization strategy in cancer cells.

Addressing nanomedicine resistance is critical for its ultimate clinical success; despite this, advancing the therapeutic designs for cancer therapy are rarely discussed in the literature. In this study, we discovered that ferroptosis is the central mechanism governing the therapeutic efficacy and resistance of treatment with zero-valent iron nanoparticles (ZVI NPs). In ZVI-sensitive oral cancer cells, ZVI NPs-induced ferroptosis was characterized by mitochondrial lipid peroxidation and reduced levels of glutathione peroxidases (GPx) in subcellular organelles. However, resistant cells could attenuate ZVI-induced oxidative stress and GPx reduction. They also showed stronger mitochondrial respiration ability, thus resisting ZVI NPs-induced mitochondrial membrane potential loss. Transcriptome comparison and quantitative polymerase chain reaction (qPCR) analysis revealed that ZVI-resistant cancer cells expressed a gene set related to enhanced NADPH supply, higher detoxification capacity of reactive oxygen species, and decreased sensitivity to ferroptosis inducers (FINs). Finally, we discovered that certain FINs were able to sensitize ZVI-resistant cancer cells to become treatable without compromising healthy non-malignant cells. These findings suggest that ferroptosis can serve as a druggable target for anti-cancer nanomedicine and therapeutic resistance modulation using ZVI NPs.

Dental cement's biological and mechanical properties improved by ZnO nanospheres.

Metal oxide nanoparticles are a new class of important materials used in a wide variety of biomedical applications. Bulk zinc oxide (ZnO) particles have been used for temporal or permanent luting cement because of their excellent mechanical strength and biocompatibility. ZnO nanoparticles have distinct optical and antibacterial properties and a high surface-to-volume ratio. We investigated the mechanical and antibacterial properties of luting cement with different ratios of ZnO nanospheres. We showed that luting cement with 5% and 10% ZnO nanospheres was less soluble in low-pH (pH 3) artificial saliva. Antibacterial activity was 40% higher for Streptococcus mutans and 90% higher for Porphyromonas gingivalis when >10% (w/v) of the bulk particles were replaced with ZnO nanospheres in ZnO polycarboxylate cement. ZnO nanospheres were also biocompatible with mammalian cells. Additionally, the compressive strength was 1.2 times greater and the diametral tensile strength was 1.5 times greater for cements with 10% ZnO nanospheres than for conventional ZnO polycarboxylate cement. We propose a new method for improving dental luting cement by integrating it with ZnO nanospheres. This method simultaneously adds their greater antibacterial, mechanical, and acid resistance properties and retains an outstanding degree of biocompatibility.