A neoteric antibacterial ceria-silver nanozyme for abiotic surfaces

Community-associated and hospital-acquired infections caused by bacteria continue to yield major global challenges to human health. Bacterial contamination on abiotic surfaces is largely spread via high-touch surfaces and contemporary standard disinfection practices show limited efficacy, resulting in unsatisfactory therapeutic outcomes. New strategies that offer non-specific and broad protection are urgently needed. Herein, we report our novel ceria-silver nanozyme engineered at a molar ratio of 5:1 and with a higher trivalent (Ce3+) surface fraction. Our results reveal potent levels of surface catalytic activity on both wet and dry surfaces, with rapid, and complete eradication of Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin resistant S. aureus, in both planktonic and biofilm form. Preferential electrostatic adherence of anionic bacteria to the cationic nanozyme surface leads to a catastrophic loss in both aerobic and anaerobic respiration, DNA damage, osmodysregulation, and finally, programmed bacterial lysis. Our data reveal several unique mechanistic avenues of synergistic ceria-Ag efficacy. Ag potentially increases the presence of Ce3+ sites at the ceria-Ag interface, thereby facilitating the formation of harmful H2O2, followed by likely permeation across the cell wall. Further, a weakened Ag-induced Ce-O bond may drive electron transfer from the Ec band to O2, thereby further facilitating the selective reduction of O2 toward H2O2 formation. Ag destabilizes the surface adsorption of molecular H2O2, potentially leading to higher concentrations of free H2O2 adjacent to bacteria. To this end, our results show that H2O2 and/or NO/NO2-/NO3- are the key liberators of antibacterial activity, with a limited immediate role being offered by nanozyme-induced ROS including O2•- and OH•, and likely other light-activated radicals. A mini-pilot proof-of-concept study performed in a pediatric dental clinic setting confirms residual, and continual nanozyme antibacterial efficacy over a 28-day period. These findings open a new approach to alleviate infections caused by bacteria for use on high-touch hard surfaces.

A therapeutically targetable positive feedback loop between lnc-HLX-2-7, HLX, and MYC that promotes group 3 medulloblastoma

Recent studies suggest that long non-coding RNAs (lncRNAs) contribute to medulloblastoma (MB) formation and progression. We have identified an lncRNA, lnc-HLX-2-7, as a potential therapeutic target in group 3 (G3) MBs. lnc-HLX-2-7 RNA specifically accumulates in the promoter region of HLX, a sense-overlapping gene of lnc-HLX-2-7, which activates HLX expression by recruiting multiple factors, including enhancer elements. RNA sequencing and chromatin immunoprecipitation reveal that HLX binds to and activates the promoters of several oncogenes, including TBX2, LIN9, HOXM1, and MYC. Intravenous treatment with cerium-oxide-nanoparticle-coated antisense oligonucleotides targeting lnc-HLX-2-7 (CNP-lnc-HLX-2-7) inhibits tumor growth by 40%-50% in an intracranial MB xenograft mouse model. Combining CNP-lnc-HLX-2-7 with standard-of-care cisplatin further inhibits tumor growth and significantly prolongs mouse survival compared with CNP-lnc-HLX-2-7 monotherapy. Thus, the lnc-HLX-2-7-HLX-MYC axis is important for regulating G3 MB progression, providing a strong rationale for using lnc-HLX-2-7 as a therapeutic target for G3 MBs.

A Multifunctional Therapeutic Strategy Using P7C3 as A Countermeasure Against Bone Loss and Fragility in An Ovariectomized Rat Model of Postmenopausal Osteoporosis

By 2060, an estimated one in four Americans will be elderly. Consequently, the prevalence of osteoporosis and fragility fractures will also increase. Presently, no available intervention definitively prevents or manages osteoporosis. This study explores whether Pool 7 Compound 3 (P7C3) reduces progressive bone loss and fragility following the onset of ovariectomy (OVX)-induced osteoporosis. Results confirm OVX-induced weakened, osteoporotic bone together with a significant gain in adipogenic body weight. Treatment with P7C3 significantly reduced osteoclastic activity, bone marrow adiposity, whole-body weight gain, and preserved bone area, architecture, and mechanical strength. Analyses reveal significantly upregulated platelet derived growth factor-BB and leukemia inhibitory factor, with downregulation of interleukin-1 R6, and receptor activator of nuclear factor kappa-B (RANK). Together, proteomic data suggest the targeting of several key regulators of inflammation, bone, and adipose turnover, via transforming growth factor-beta/SMAD, and Wingless-related integration site/be-catenin signaling pathways. To the best of the knowledge, this is first evidence of an intervention that drives against bone loss via RANK. Metatranscriptomic analyses of the gut microbiota show P7C3 increased Porphyromonadaceae bacterium, Candidatus Melainabacteria, and Ruminococcaceae bacterium abundance, potentially contributing to the favorable inflammatory, and adipo-osteogenic metabolic regulation observed. The results reveal an undiscovered, and multifunctional therapeutic strategy to prevent the pathological progression of OVX-induced bone loss.

3D printed bioabsorbable composite scaffolds of poly (lactic acid)-tricalcium phosphate-ceria with osteogenic property for bone regeneration

The fabrication of customized implants by additive manufacturing has allowed continued development of the personalized medicine field. Herein, a 3D-printed bioabsorbable poly (lactic acid) (PLA)- β-tricalcium phosphate (TCP) (10 wt %) composite has been modified with CeO2 nanoparticles (CeNPs) (1, 5 and 10 wt %) for bone repair. The filaments were prepared by melt extrusion and used to print porous scaffolds. The nanocomposite scaffolds possessed precise structure with fine print resolution, a homogenous distribution of TCP and CeNP components, and mechanical properties appropriate for bone tissue engineering applications. Cell proliferation assays using osteoblast cultures confirmed the cytocompatibility of the composites. In addition, the presence of CeNPs enhanced the proliferation and differentiation of mesenchymal stem cells; thereby, increasing alkaline phosphatase (ALP) activity, calcium deposition and bone-related gene expression. Results from this study have shown that the 3D printed PLA-TCP-10%CeO2 composite scaffold could be used as an alternative polymeric implant for bone tissue engineering applications: avoiding additional/revision surgeries and accelerating the regenerative process.

Surface Chemistry of Biologically Active Reducible Oxide Nanozymes

Reducible metal oxide nanozymes (rNZs) are a subject of intense recent interest due to their catalytic nature, ease of synthesis, and complex surface character. Such materials contain surface sites which facilitate enzyme-mimetic reactions via substrate coordination and redox cycling. Further, these surface reactive sites are shown to be highly sensitive to stresses within the nanomaterial lattice, the physicochemical environment, and to processing conditions occurring as part of their syntheses. When administered in vivo, a complex protein corona binds to the surface, redefining its biological identity and subsequent interactions within the biological system. Catalytic activities of rNZs each deliver a differing impact on protein corona formation, its composition, and in turn, their recognition, and internalization by host cells. Improving the understanding of the precise principles that dominate rNZ surface-biomolecule adsorption raises the question of whether designer rNZs can be engineered to prevent corona formation, or indeed to produce "custom" protein coronas applied either in vitro, and preadministration, or formed immediately upon their exposure to body fluids. Here, fundamental surface chemistry processes and their implications in rNZ material performance are considered. In particular, material structures which inform component adsorption from the application environment, including substrates for enzyme-mimetic reactions are discussed.

Effect of Silicon Dioxide and Magnesium Oxide on the Printability, Degradability, Mechanical Strength and Bioactivity of 3D Printed Poly (Lactic Acid)-Tricalcium Phosphate Composite Scaffolds

BACKGROUND

Poly (lactic acid) (PLA) is a biodegradable polyester that has been exploited for a variety of biomedical applications, including tissue engineering. The incorporation of β-tricalcium phosphate (TCP) into PLA has imparted bioactivity to the polymeric matrix.

METHODS

We have modified a 90%PLA-10%TCP composite with SiO2 and MgO (1, 5 and 10 wt%), separately, to further enhance the material bioactivity. Filaments were prepared by extrusion, and scaffolds were fabricated using 3D printing technology associated with fused filament fabrication.

RESULTS

The PLA-TCP-SiO2 composites presented similar structural, thermal, and rheological properties to control PLA and PLA-TCP. In contrast, the PLA-TCP-MgO composites displayed absence of crystallinity, lower polymeric molecular weight, accelerated degradation ratio, and decreased viscosity within the 3D printing shear rate range. SiO2 and MgO particles were homogeneously dispersed within the PLA and their incorporation increased the roughness and protein adsorption of the scaffold, compared to a PLA-TCP scaffold. This favorable surface modification promoted cell proliferation, suggesting that SiO2 and MgO may have potential for enhancing the bio-integration of scaffolds in tissue engineering applications. However, high loads of MgO accelerated the polymeric degradation, leading to an acid environment that imparted the composite biocompatibility. The presence of SiO2 stimulated mesenchymal stem cells differentiation towards osteoblast; enhancing extracellular matrix mineralization, alkaline phosphatase (ALP) activity, and bone-related genes expression.

CONCLUSION

The PLA-10%TCP-10%SiO2 composite presented the most promising results, especially for bone tissue regeneration, due to its intense osteogenic behavior. PLA-10%TCP-10%SiO2 could be used as an alternative implant for bone tissue engineering application.

miRNA-211 maintains metabolic homeostasis in medulloblastoma through its target gene long-chain acyl-CoA synthetase 4

The prognosis of childhood medulloblastoma (MB) is often poor, and it usually requires aggressive therapy that adversely affects quality of life. microRNA-211 (miR-211) was previously identified as an important regulator of cells that descend from neural cells. Since medulloblastomas primarily affect cells with similar ontogeny, we investigated the role and mechanism of miR-211 in MB. Here we showed that miR-211 expression was highly downregulated in cell lines, PDXs, and clinical samples of different MB subgroups (SHH, Group 3, and Group 4) compared to normal cerebellum. miR-211 gene was ectopically expressed in transgenic cells from MB subgroups, and they were subjected to molecular and phenotypic investigations. Monoclonal cells stably expressing miR-211 were injected into the mouse cerebellum. miR-211 forced expression acts as a tumor suppressor in MB both in vitro and in vivo, attenuating growth, promoting apoptosis, and inhibiting invasion. In support of emerging regulatory roles of metabolism in various forms of cancer, we identified the acyl-CoA synthetase long-chain family member (ACSL4) as a direct miR-211 target. Furthermore, lipid nanoparticle-coated, dendrimer-coated, and cerium oxide-coated miR-211 nanoparticles were applied to deliver synthetic miR-211 into MB cell lines and cellular responses were assayed. Synthesizing nanoparticle-miR-211 conjugates can suppress MB cell viability and invasion in vitro. Our findings reveal miR-211 as a tumor suppressor and a potential therapeutic agent in MB. This proof-of-concept paves the way for further pre-clinical and clinical development.

Inorganic Nanoparticles as Radiosensitizers for Cancer Treatment

Nanotechnology has expanded what can be achieved in our approach to cancer treatment. The ability to produce and engineer functional nanoparticle formulations to elicit higher incidences of tumor cell radiolysis has resulted in substantial improvements in cancer cell eradication while also permitting multi-modal biomedical functionalities. These radiosensitive nanomaterials utilize material characteristics, such as radio-blocking/absorbing high-Z atomic number elements, to mediate localized effects from therapeutic irradiation. These materials thereby allow subsequent scattered or emitted radiation to produce direct (e.g., damage to genetic materials) or indirect (e.g., protein oxidation, reactive oxygen species formation) damage to tumor cells. Using nanomaterials that activate under certain physiologic conditions, such as the tumor microenvironment, can selectively target tumor cells. These characteristics, combined with biological interactions that can target the tumor environment, allow for localized radio-sensitization while mitigating damage to healthy cells. This review explores the various nanomaterial formulations utilized in cancer radiosensitivity research. Emphasis on inorganic nanomaterials showcases the specific material characteristics that enable higher incidences of radiation while ensuring localized cancer targeting based on tumor microenvironment activation. The aim of this review is to guide future research in cancer radiosensitization using nanomaterial formulations and to detail common approaches to its treatment, as well as their relations to commonly implemented radiotherapy techniques.

Infrared and Raman Diagnostic Modeling of Phosphate Adsorption on Ceria Nanoparticles

Cerium dioxide (CeO2; ceria) nanoparticles (CeNPs) are promising nanozymes that show a variety of biological activity. Effective nanozymes need to retain their activity in the face of surface speciation in biological environments, and characterizing surface speciation is therefore critical to understanding and controlling the therapeutic capabilities of CeNPs. In particular, adsorbed phosphates can impact the enzymatic activity exploited to convert phosphate prodrugs into therapeutics in vivo and also define the early stages of the phosphate-scavenging processes that lead to the transformation of active CeO2 into inactive CePO4. In this work, we utilize ab initio lattice-dynamics calculations to study the interaction of phosphates with the three major surfaces of ceria and to predict the infrared (IR) and Raman spectral signatures of adsorbed phosphate species. We find that phosphates adsorb strongly to CeO2 surfaces in a range of stable binding configurations, of which 5-fold coordinated P species in a trigonal bipyramidal coordination may represent a stable intermediate in the early stages of phosphate scavenging. We find that the phosphate species show characteristic spectral fingerprints between 500 and 1500 cm-1, whereas the bare CeO2 surfaces show no active modes above 600 cm-1, and the 5-fold coordinated P species in particular show potential diagnostic P-O stretching modes between 650 and 700 cm-1 in both IR and Raman spectra. This comprehensive exploration of different binding modes for phosphates on CeO2 and the set of reference spectra provides an important step toward the experimental characterization of phosphate speciation and, ultimately, control of its impact on the performance of ceria nanozymes.

Ultrasound-Responsive Nanobubbles for Combined siRNA-Cerium Oxide Nanoparticle Delivery to Bone Cells

This study aims to present an ultrasound-mediated nanobubble (NB)-based gene delivery system that could potentially be applied in the future to treat bone disorders such as osteoporosis. NBs are sensitive to ultrasound (US) and serve as a controlled-released carrier to deliver a mixture of Cathepsin K (CTSK) siRNA and cerium oxide nanoparticles (CeNPs). This platform aimed to reduce bone resorption via downregulating CTSK expression in osteoclasts and enhance bone formation via the antioxidant and osteogenic properties of CeNPs. CeNPs were synthesized and characterized using transmission electron microscopy and X-ray photoelectron spectroscopy. The mixture of CTSK siRNA and CeNPs was adsorbed to the surface of NBs using a sonication method. The release profiles of CTSK siRNA and CeNPs labeled with a fluorescent tag molecule were measured after low-intensity pulsed ultrasound (LIPUS) stimulation using fluorescent spectroscopy. The maximum release of CTSK siRNA and the CeNPs for 1 mg/mL of NB-(CTSK siRNA + CeNPs) was obtained at 2.5 nM and 1 µg/mL, respectively, 3 days after LIPUS stimulation. Then, Alizarin Red Staining (ARS) was applied to human bone marrow-derived mesenchymal stem cells (hMSC) and tartrate-resistant acid phosphatase (TRAP) staining was applied to human osteoclast precursors (OCP) to evaluate osteogenic promotion and osteoclastogenic inhibition effects. A higher mineralization and a lower number of osteoclasts were quantified for NB-(CTSK siRNA + CeNPs) versus control +RANKL with ARS (p < 0.001) and TRAP-positive staining (p < 0.01). This study provides a method for the delivery of gene silencing siRNA and CeNPs using a US-sensitive NB system that could potentially be used in vivo and in the treatment of bone fractures and disorders such as osteoporosis.

Nanotechnology enabled radioprotectants to reduce space radiation-induced reactive oxidative species

Interest in space exploration has seen substantial growth following recent launch and operation of modern space technologies. In particular, the possibility of travel beyond low earth orbit is seeing sustained support. However, future deep space travel requires addressing health concerns for crews under continuous, longer-term exposure to adverse environmental conditions. Among these challenges, radiation-induced health issues are a major concern. Their potential to induce chronic illness is further potentiated by the microgravity environment. While investigations into the physiological effects of space radiation are still under investigation, studies on model ionizing radiation conditions, in earth and micro-gravity conditions, can provide needed insight into relevant processes. Substantial formation of high, sustained reactive oxygen species (ROS) evolution during radiation exposure is a clear threat to physiological health of space travelers, producing indirect damage to various cell structures and requiring therapeutic address. Radioprotection toward the skeletal system components is essential to astronaut health, due to the high radio-absorption cross-section of bone mineral and local hematopoiesis. Nanotechnology can potentially function as radioprotectant and radiomitigating agents toward ROS and direct radiation damage. Nanoparticle compositions such as gold, silver, platinum, carbon-based materials, silica, transition metal dichalcogenides, and ceria have all shown potential as viable radioprotectants to mitigate space radiation effects with nanoceria further showing the ability to protect genetic material from oxidative damage in several studies. As research into space radiation-induced health problems develops, this review intends to provide insights into the nanomaterial design to ameliorate pathological effects from ionizing radiation exposure. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Nanotechnology Approaches to Biology > Cells at the Nanoscale Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Examining sialic acid derivatives as potential inhibitors of SARS-CoV-2 spike protein receptor binding domain

Severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) has been the primary reason behind the COVID-19 global pandemic which has affected millions of lives worldwide. The fundamental cause of the infection is the molecular binding of the viral spike protein receptor binding domain (SP-RBD) with the human cell angiotensin-converting enzyme 2 (ACE2) receptor. The infection can be prevented if the binding of RBD-ACE2 is resisted by utilizing certain inhibitors or drugs that demonstrate strong binding affinity towards the SP RBD. Sialic acid based glycans found widely in human cells and tissues have notable propensity of binding to viral proteins of the coronaviridae family. Recent experimental literature have used N-acetyl neuraminic acid (Sialic acid) to create diagnostic sensors for SARS-CoV-2, but a detailed interrogation of the underlying molecular mechanisms is warranted. Here, we perform all atom molecular dynamics (MD) simulations for the complexes of certain Sialic acid-based molecules with that of SP RBD of SARS CoV-2. Our results indicate that Sialic acid not only reproduces a binding affinity comparable to the RBD-ACE2 interactions, it also assumes the longest time to dissociate completely from the protein binding pocket of SP RBD. Our predictions corroborate that a combination of electrostatic and van der Waals energies as well the polar hydrogen bond interactions between the RBD residues and the inhibitors influence free energy of binding.Communicated by Ramaswamy H. Sarma.

Broad-Spectrum, Potent, and Durable Ceria Nanoparticles Inactivate RNA Virus Infectivity by Targeting Virion Surfaces and Disrupting Virus-Receptor Interactions

There is intense interest in developing long-lasting, potent, and broad-spectrum antiviral disinfectants. Ceria nanoparticles (CNPs) can undergo surface redox reactions (Ce³⁺ ↔ Ce⁴⁺) to generate ROS without requiring an external driving force. Here, we tested the mechanism behind our prior finding of potent inactivation of enveloped and non-enveloped RNA viruses by silver-modified CNPs, AgCNP1 and AgCNP2. Treatment of human respiratory viruses, coronavirus OC43 and parainfluenza virus type 5 (PIV5) with AgCNP1 and 2, respectively, prevented virus interactions with host cell receptors and resulted in virion aggregation. Rhinovirus 14 (RV14) mutants were selected to be resistant to inactivation by AgCNP2. Sequence analysis of the resistant virus genomes predicted two amino acid changes in surface-located residues D91V and F177L within capsid protein VP1. Consistent with the regenerative properties of CNPs, surface-applied AgCNP1 and 2 inactivated a wide range of structurally diverse viruses, including enveloped (OC43, SARS-CoV-2, and PIV5) and non-enveloped RNA viruses (RV14 and feline calicivirus; FCV). Remarkably, a single application of AgCNP1 and 2 potently inactivated up to four sequential rounds of virus challenge. Our results show broad-spectrum and long-lasting anti-viral activity of AgCNP nanoparticles, due to targeting of viral surface proteins to disrupt interactions with cellular receptors.

CNP-miR146a improves outcomes in a two-hit acute- and ventilator-induced lung injury model

Acute respiratory distress syndrome (ARDS) has high mortality (~40 %) and requires the lifesaving intervention of mechanical ventilation. A variety of systemic inflammatory insults can progress to ARDS, and the inflamed and injured lung is susceptible to ventilator-induced lung injury (VILI). Strategies to mitigate the inflammatory response while restoring pulmonary function are limited, thus we sought to determine if treatment with CNP-miR146a, a conjugate of novel free radical scavenging cerium oxide nanoparticles (CNP) to the anti-inflammatory microRNA (miR)-146a, would protect murine lungs from acute lung injury (ALI) induced with intratracheal endotoxin and subsequent VILI. Lung injury severity and treatment efficacy were evaluated via lung mechanical function, relative gene expression of inflammatory biomarkers, and lung morphometry (stereology). CNP-miR146a reduced the severity of ALI and slowed the progression of VILI, evidenced by improvements in inflammatory biomarkers, atelectasis, gas volumes in the parenchymal airspaces, and the stiffness of the pulmonary system.

BindingSite-AugmentedDTA: enabling a next-generation pipeline for interpretable prediction models in drug repurposing

While research into drug-target interaction (DTI) prediction is fairly mature, generalizability and interpretability are not always addressed in the existing works in this field. In this paper, we propose a deep learning (DL)-based framework, called BindingSite-AugmentedDTA, which improves drug-target affinity (DTA) predictions by reducing the search space of potential-binding sites of the protein, thus making the binding affinity prediction more efficient and accurate. Our BindingSite-AugmentedDTA is highly generalizable as it can be integrated with any DL-based regression model, while it significantly improves their prediction performance. Also, unlike many existing models, our model is highly interpretable due to its architecture and self-attention mechanism, which can provide a deeper understanding of its underlying prediction mechanism by mapping attention weights back to protein-binding sites. The computational results confirm that our framework can enhance the prediction performance of seven state-of-the-art DTA prediction algorithms in terms of four widely used evaluation metrics, including concordance index, mean squared error, modified squared correlation coefficient ($r^2_m$) and the area under the precision curve. We also contribute to three benchmark drug-traget interaction datasets by including additional information on 3D structure of all proteins contained in those datasets, which include the two most commonly used datasets, namely Kiba and Davis, as well as the data from IDG-DREAM drug-kinase binding prediction challenge. Furthermore, we experimentally validate the practical potential of our proposed framework through in-lab experiments. The relatively high agreement between computationally predicted and experimentally observed binding interactions supports the potential of our framework as the next-generation pipeline for prediction models in drug repurposing.

An osteogenic magnesium alloy with improved corrosion resistance, antibacterial, and mechanical properties for orthopedic applications

The aim of this study was to develop a novel biodegradable magnesium (Mg) alloy for bone implant applications. We used scandium (Sc; 2 wt %) and strontium (Sr; 2 wt %) as alloying elements due to their high biocompatibility, antibacterial efficacy, osteogenesis, and protective effects against corrosion. In the present work, we also examined the effect of a heat treatment process on the properties of the Mg-Sc-Sr alloy. Alloys were manufactured using a metal casting process followed by heat treatment. The microstructure, corrosion, mechanical properties, antibacterial activity, and osteogenic activity of the alloy were assessed in vitro. The results showed that the incorporation of Sc and Sr elements controlled the corrosion, reduced the hydrogen generation, and enhanced mechanical properties. Furthermore, alloying with Sc and Sr demonstrated a significantly enhanced antibacterial activity and decreased biofilm formation compared to control Mg. Also, culturing Mg-Sc-Sr alloy with human bone marrow-derived mesenchymal stromal cells showed a high degree of biocompatibility (>90% live cells) and a significant increase in osteoblastic differentiation in vitro shown by Alizarin red staining and alkaline phosphatase activity. Based on these results, the Mg-Sc-Sr alloy heat-treated at 400°C displayed optimal mechanical properties, corrosion rate, antibacterial efficacy, and osteoinductivity. These characteristics make the Mg-Sc-Sr alloy a promising candidate for biodegradable orthopedic implants in the fixation of bone fractures such as bone plate-screws or intramedullary nails.

Cerium Oxide Nanoparticles Conjugated with Tannic Acid Prevent UVB-Induced Oxidative Stress in Fibroblasts: Evidence of a Promising Anti-Photodamage Agent

Exposure to ultraviolet radiation induces photodamage towards cellular macromolecules that can progress to photoaging and photocarcinogenesis. The topical administration of compounds that maintain the redox balance in cells presents an alternative approach to combat skin oxidative damage. Cerium oxide nanoparticles (CNPs) can act as antioxidants due to their enzyme-like activity. In addition, a recent study from our group has demonstrated the photoprotective potential of tannic acid (TA). Therefore, this work aimed to synthesize CNPs associated with TA (CNP-TA) and investigate its photoprotective activity in L929 fibroblasts exposed to UVB radiation. CNP conjugation with TA was confirmed by UV-Vis spectra and X-ray photoelectron spectroscopy. Bare CNPs and CNP-TA exhibited particle sizes of ~5 and ~10 nm, superoxide dismutase activity of 3724 and 2021 unit/mg, and a zeta potential of 23 and -19 mV, respectively. CNP-TA showed lower cytotoxicity than free TA and the capacity to reduce the oxidative stress caused by UVB; supported by the scavenging of reactive oxygen species, the prevention of endogenous antioxidant system depletion, and the reduction in oxidative damage in lipids and DNA. Additionally, CNP-TA improved cell proliferation and decreased TGF-β, metalloproteinase-1, and cyclooxygenase-2. Based on these results, CNP-TA shows therapeutic potential for protection against photodamage, decreasing molecular markers of photoaging and UVB-induced inflammation.

Assessing the bio-stability of microRNA-146a conjugated nanoparticles via electroanalysis

The number of diabetics is increasing worldwide and is associated with significant instances of clinical morbidity. Increased amounts of reactive oxygen species (ROS) and proinflammatory cytokines are associated with the pathogenesis of diabetic wounds and result in a significant delay in healing. Our previous studies have shown the ability of a cerium oxide nanoparticle (CNP) formulation conjugated with the anti-inflammatory microRNA miR146a (CNP-miR146a) to enhance the healing of diabetic wounds. The observed therapeutic activity exceeded the combined efficacies of the individual conjugate components (CNPs and miR146a alone), suggesting a synergistic effect. The current study evaluates whether the previously observed enhanced activity arises from increased agent delivery (simple nanocarrier activity) or is specific to the CNP-miR146a formulation (functional, bio-active nanomaterial). Comparison with miR146a conjugated gold (bioactive, metal) and silica (bioinert, oxide) nanoparticles (AuNPs and SiO₂NPs) was performed in the presence of H₂O₂, as an analogue to the high levels of ROS present in the diabetic wound environment. Electrochemical studies, materials characterization, and chemical assays showed limited interaction of AuNP-miR146a with H₂O₂ and instability of SiO₂NP-miR146a over time. In contrast, and in support of our prior results, CNP-miR146a displayed chemical stability and persistent ROS scavenging ability. Furthermore, it was determined that CNPs protect miR146a from oxidative damage under prolonged exposure to H₂O₂, whereas AuNPs and SiO₂NPs were shown to be ineffective. Overall, these results reinforce the ability of CNPs to stabilize and protect miRNA while exhibiting robust antioxidant properties, suggesting that therapeutic activity observed in related earlier studies is not limited to a facile nanocarrier function.

Noninvasive Delivery of Self-Regenerating Cerium Oxide Nanoparticles to Modulate Oxidative Stress in the Retina

Diseases affecting the retina, such as age-related macular degeneration (AMD), diabetic retinopathy, macular edema, and retinal vein occlusions, are currently treated by the intravitreal injection of drug formulations. These disease pathologies are driven by oxidative damage due to chronic high concentrations of reactive oxygen species (ROS) in the retina. Intravitreal injections often induce retinal detachment, intraocular hemorrhage, and endophthalmitis. Furthermore, the severe eye pain associated with these injections lead to patient noncompliance and treatment discontinuation. Hence, there is a critical need for the development of a noninvasive therapy that is effective for a prolonged period for treating retinal diseases. In this study, we developed a noninvasive cerium oxide nanoparticle (CNP) delivery wafer (Cerawafer) for the modulation of ROS in the retina. We fabricated Cerawafer loaded with CNP and determined its SOD-like enzyme-mimetic activity and ability to neutralize ROS generated in vitro. We demonstrated Cerawafer's ability to deliver CNP in a noninvasive fashion to the retina in healthy mouse eyes and the CNP retention in the retina for more than a week. Our studies have demonstrated the in vivo efficacy of the Cerawafer to modulate ROS and associated down-regulation of VEGF expression in the retinas of very-low-density lipoprotein receptor knockout (vldlr-/-) mouse model. The development of a Cerawafer nanotherapeutic will fulfill a hitherto unmet need. Currently, there is no such therapeutic available, and the development of a Cerawafer nanotherapeutic will be a major advancement in the treatment of retinal diseases.

Engineered Faceted Cerium Oxide Nanoparticles for Therapeutic miRNA Delivery

In general, wound healing is a highly ordered process, with distinct phases of inflammation, proliferation, and remodeling. However, among diabetic patients, the progression through these phases is often impeded by increased level of oxidative stress and persistent inflammation. Our previous studies demonstrated that cerium oxide nanoparticles (CNPs) conjugated with therapeutic microRNA146a (miR146a) could effectively enhance wound healing by targeting the NFκB pathway, reducing oxidative stress and inflammation. In the present study, we consider the potential effects of nanomaterial surface-faceting and morphology on the efficacy of miRNA delivery. Compared with octahedral-CNPs and cubic-CNPs, rod-CNPs exhibited higher loading capacity. In addition, in comparing the influence of particle morphology on wound healing efficacy, several markers for bioactivity were evaluated and ascribed to the combined effects of the gene delivery and reactive oxygen species (ROS) scavenging properties. In the cellular treatment study, rod-CNP-miR146a displayed the greatest miR146a delivery into cells. However, the reduction of IL-6 was only observed in the octahedral-CNP-miR146a, suggesting that the efficacy of the miRNA delivery is a result of the combination of various factors. Overall, our results give enlightenments into the relative delivery efficiency of the CNPs with different morphology enhancing miRNA delivery efficacy.

DDDR-31. THE THERAPEUTIC POTENTIAL OF THE LONG NON-CODING RNA LNC-HLX-2-7 IN GROUP 3 MEDULLOBLASTOMAS IN CHILDREN

Medulloblastoma (MB) is an aggressive brain tumor that predominantly affects children. Recent high-throughput sequencing studies suggest that the non-coding RNA genome, in particular long non-coding RNAs (lncRNAs), contributes to MB formation and tumor progression. Here we report the identification of a novel lncRNA, lnc-HLX-2-7, as a potential therapeutic target in group 3 MBs. In this study, we report that lnc-HLX-2-7 RNA specifically accumulates in the HLX (host gene of lnc-HLX-2-7) promoter region and activates HLX expression by recruiting multiple factors including enhancer elements. RNA sequencing and chromatin immunoprecipitation revealed that HLX directly binds to the promoters of several tumor-promoting genes, including MYC, and activates their expression. Furthermore, intravenous treatment with antisense oligonucleotides targeting lnc-HLX-2-7 coated with cerium-oxide nanoparticle (CNP-lnc-HLX-2-7) reduced tumor growth (40-50%) in intracranial MB xenograft mouse model (n = 10, p &lt; 0.01, t-test). We found that the combinatorial therapy of CNP-lnc-HLX-2-7 and cisplatin further inhibits tumor growth and significantly prolongs mouse survival compared to CNP-lnc-HLX-2-7 monotherapy (n = 10, p &lt; 0.01, t-test) only. We report here the importance of the lnc-HLX-2-7-HLX-MYC axis in regulating group 3 MB progression and provide a strong rationale for using lnc-HLX-2-7 as a specific and potent therapeutic target for the group 3 MBs in children.

A novel approach for the prevention of ionizing radiation-induced bone loss using a designer multifunctional cerium oxide nanozyme

The disability, mortality and costs due to ionizing radiation (IR)-induced osteoporotic bone fractures are substantial and no effective therapy exists. Ionizing radiation increases cellular oxidative damage, causing an imbalance in bone turnover that is primarily driven via heightened activity of the bone-resorbing osteoclast. We demonstrate that rats exposed to sublethal levels of IR develop fragile, osteoporotic bone. At reactive surface sites, cerium ions have the ability to easily undergo redox cycling: drastically adjusting their electronic configurations and versatile catalytic activities. These properties make cerium oxide nanomaterials fascinating. We show that an engineered artificial nanozyme composed of cerium oxide, and designed to possess a higher fraction of trivalent (Ce³⁺) surface sites, mitigates the IR-induced loss in bone area, bone architecture, and strength. These investigations also demonstrate that our nanozyme furnishes several mechanistic avenues of protection and selectively targets highly damaging reactive oxygen species, protecting the rats against IR-induced DNA damage, cellular senescence, and elevated osteoclastic activity in vitro and in vivo. Further, we reveal that our nanozyme is a previously unreported key regulator of osteoclast formation derived from macrophages while also directly targeting bone progenitor cells, favoring new bone formation despite its exposure to harmful levels of IR in vitro. These findings open a new approach for the specific prevention of IR-induced bone loss using synthesis-mediated designer multifunctional nanomaterials.

Potent Inactivation of Human Respiratory Viruses Including SARS-CoV-2 by a Photoactivated Self-Cleaning Regenerative Antiviral Coating

The COVID-19 pandemic marks an inflection point in the perception and treatment of human health. Substantial resources have been reallocated to address the direct medical effects of COVID-19 and to curtail the spread of the virus. Thereby, shortcomings of traditional disinfectants, especially their requirement for regular reapplication and the related complications (e.g., dedicated personnel and short-term activity), have become issues at the forefront of public health concerns. This issue became especially pressing when infection-mitigating supplies dwindled early in the progression of the pandemic. In consideration of the constant threat posed by emerging novel viruses, we report a platform technology for persistent surface disinfection to combat virus transmission through nanomaterial-mediated, localized UV radiation emission. In this work, two formulations of Y2SiO5-based visible-to-UV upconversion nanomaterials were developed using a facile sol-gel-based synthesis. Our formulations have shown substantial antiviral activities (4 × 104 to 0 TCID50 units in 30 min) toward an enveloped, circulating human coronavirus strain (OC43) under simple white light exposure as an analogue to natural light or common indoor lighting. Additionally, we have shown that our two formulations greatly reduce OC43 RNA recovery from surfaces. Antiviral activities were further demonstrated toward a panel of structurally diverse viruses including enveloped viruses, SARS-CoV-2, vaccinia virus, vesicular stomatitis virus, parainfluenza virus, and Zika virus, as well as nonenveloped viruses, rhinovirus, and calicivirus, as evidence of the technology's broad antiviral activity. Remarkably, one formulation completely inactivated 105 infectious units of SARS-CoV-2 in only 45 min. The detailed technology has implications for the design of more potent, long-lived disinfectants and modified/surface-treated personal protective equipment targeting a wide range of viruses.

AttentionSiteDTI: an interpretable graph-based model for drug-target interaction prediction using NLP sentence-level relation classification

In this study, we introduce an interpretable graph-based deep learning prediction model, AttentionSiteDTI, which utilizes protein binding sites along with a self-attention mechanism to address the problem of drug-target interaction prediction. Our proposed model is inspired by sentence classification models in the field of Natural Language Processing, where the drug-target complex is treated as a sentence with relational meaning between its biochemical entities a.k.a. protein pockets and drug molecule. AttentionSiteDTI enables interpretability by identifying the protein binding sites that contribute the most toward the drug-target interaction. Results on three benchmark datasets show improved performance compared with the current state-of-the-art models. More significantly, unlike previous studies, our model shows superior performance, when tested on new proteins (i.e. high generalizability). Through multidisciplinary collaboration, we further experimentally evaluate the practical potential of our proposed approach. To achieve this, we first computationally predict the binding interactions between some candidate compounds and a target protein, then experimentally validate the binding interactions for these pairs in the laboratory. The high agreement between the computationally predicted and experimentally observed (measured) drug-target interactions illustrates the potential of our method as an effective pre-screening tool in drug repurposing applications.

Antiviral nanopharmaceuticals: Engineered surface interactions and virus-selective activity

The COVID-19 pandemic has inspired large research investments from the global scientific community in the study of viral properties and antiviral technologies (e.g., self-cleaning surfaces, virucides, antiviral drugs, and vaccines). Emerging viruses are a constant threat due to the substantial variation in viral structures, limiting the potential for expanded broad-spectrum antiviral agent development, and the complexity of targeting multiple and diverse viral species with unique characteristics involving their virulence. Multiple, more infectious variants of SARS-CoV2 (e.g., Delta, Omicron) have already appeared, necessitating research into versatile, robust control strategies in response to the looming threat of future viruses. Nanotechnology and nanomaterials have played a vital role in addressing current viral threats, from mRNA-based vaccines to nanoparticle-based drugs and nanotechnology enhanced disinfection methods. Rapid progress in the field has prompted a review of the current literature primarily focused on nanotechnology-based virucides and antivirals. In this review, a brief description of antiviral drugs is provided first as background with most of the discussion focused on key design considerations for high-efficacy antiviral nanomaterials (e.g., nanopharmaceuticals) as determined from published studies as well as related modes of biological activity. Insights into potential future research directions are also provided with a section devoted specifically to the SARS-CoV2 virus. This article is categorized under: Toxicology and Regulatory Issues in Nanomediciney > Toxicology of Nanomaterials Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Respiratory Disease.

Photopolymerized Zwitterionic Hydrogels with a Sustained Delivery of Cerium Oxide Nanoparticle-miR146a Conjugate Accelerate Diabetic Wound Healing

In the United States, $87 billion per year is spent on the care of diabetic ulcers alone. Although the pathophysiology of diabetic wound healing is multifaceted, high systemic levels of inflammation and increased reactive oxygen species are often implicated in the wound healing impairment. Zwitterionic materials have been demonstrated to reduce inflammation and increase extracellular matrix deposition in wound beds, and here, we demonstrate a fabrication method for photopolymerized zwitterionic hydrogels that also enables sustained drug delivery over time. A therapeutic molecule of interest that is examined in this work is cerium oxide nanoparticle tagged with microRNA-146a (CNP-miR146a) to combat both oxidative stress and inflammation. The hydrogels are composed of zwitterionic and nonzwitterionic monomers, and the hydrogel formation occurs in the absence of a crosslinker. The hydrogels exhibit a wide range of stiffness and mechanical properties depending on their monomer content. Additionally, these hydrogels exhibit sustained release of nanoparticles and proteins. Finally, when employed in an in vivo diabetic mouse wound healing model, the zwitterionic hydrogels alone and laden with the CNP-miR146a conjugate significantly improved the rate of diabetic wound healing. Overall, these materials have excellent potential to be used as a topical treatment for chronic diabetic wounds.

Cerium oxide nanoparticle conjugation to microRNA-146a mechanism of correction for impaired diabetic wound healing

Diabetic wounds represent a significant healthcare burden and are characterized by impaired wound healing due to increased oxidative stress and persistent inflammation. We have shown that CNP-miR146a synthesized by the conjugation of cerium oxide nanoparticles (CNP) to microRNA (miR)-146a improves diabetic wound healing. CNP are divalent metal oxides that act as free radical scavenger, while miR146a inhibits the pro-inflammatory NFκB pathway, so CNP-miR146a has a synergistic role in modulating both oxidative stress and inflammation. In this study, we define the mechanism(s) by which CNP-miR146a improves diabetic wound healing by examining immunohistochemical and gene expression analysis of markers of inflammation, oxidative stress, fibrosis, and angiogenesis. We have found that intradermal injection of CNP-miR146a increases wound collagen, enhances angiogenesis, and lowers inflammation and oxidative stress, ultimately promoting faster closure of diabetic wounds.

ALD based nanostructured zinc oxide coated antiviral silk fabric

The COVID-19 pandemic has underscored the importance of research and development in maintaining public health. Facing unprecedented challenges, the scientific community developed antiviral drugs, virucides, and vaccines to combat the infection within the past two years. However, an ever-increasing list of highly infectious SARS-CoV-2 variants (gamma, delta, omicron, and now ba.2 stealth) has exacerbated the problem: again raising the issues of infection prevention strategies and the efficacy of personal protective equipment (PPE). Against this backdrop, we report an antimicrobial fabric for PPE applications. We have fabricated a nanofibrous silk-PEO material using electrospinning followed by zinc oxide thin film deposition by employing the atomic layer deposition technique. The composite fabric has shown 85% more antibacterial activity than the control fabric and was found to possess substantial superoxide dismutase–mimetic activity. The composite was further subjected to antiviral testing using two different respiratory tract viruses: coronavirus (OC43: enveloped) and rhinovirus (RV14: non-enveloped). We report a 95% reduction in infectious virus for both OC43 and RV14 from an initial load of ∼1 × 10⁵ (sample size: 6 mm dia. disk), after 1 h of white light illumination. Furthermore, with 2 h of illumination, ∼99% reduction in viral infectivity was observed for RV14. High activity in a relatively small area of fabric (3.5 × 10³ viral units per mm²) makes this antiviral fabric ideal for application in masks/PPE, with an enhanced ability to prevent antimicrobial infection overall.

This study presents an antiviral self-cleaning fabric for masks/PPE applications with protection against human coronavirus.

GO-CeO₂ nanohybrid for ultra-rapid fluoride removal from drinking water

The presence of excess fluoride (F^- > 1.5 mg/L) in drinking water affects more than 260 million people globally and leads to dental and skeletal fluorosis among other health problems. This study investigated fluoride removal by graphene oxide-ceria nanohybrid (GO-CeO₂) and elucidated the mechanisms involved. The nanohybrid exhibited ultra-rapid kinetics for fluoride removal and the equilibrium (85% removal, 10 mg F^-/L initial concentration) was achieved within 1 min which is one of the fastest kinetics for fluoride removal reported so far. Fluoride removal by the nanohybrid followed Langmuir isotherm with a maximum adsorption capacity of 8.61 mg/g at pH 6.5 and that increased to 16.07 mg/g when the pH was lowered to 4.0. Based on the experimental results and characterization data, we have postulated that both electrostatic interaction and surface complexation participated in the fluoride removal process. The O^2- ions present in the CeO₂ lattice were replaced by F^- ions to make a coordination compound (complex). While both Ce⁴⁺ and Ce³⁺ were present in ceria nanoparticles (CeO₂ NPs), Ce³⁺ participated in fluoride complexation. During fluoride removal by GO-CeO₂, the GO sheets acted as electron mediators and help to reduce Ce⁴⁺ to Ce³⁺ at the CeO₂ NPs-GO interface, and the additional Ce³⁺ enhanced fluoride removal by the nanohybrid.

Sensitization of breast cancer to Herceptin by redox active nanoparticles

Herceptin-resistant tumor relapse remains a major clinical issue responsible for the poor prognosis of HER2⁺ breast cancer. Understanding the underlying mechanisms and finding a therapeutic solution are of paramount urgency to improve the patient management. Here we report that anticancer redox active cerium oxide nanoparticles (CONPs) can potently sensitize the cancer cells to the cytotoxicity of Herceptin. By comparing between Herceptin-sensitive and Herceptin-resistant human breast cancer cell lines under normoxic as well as hypoxic culture conditions, we found that in the presence of CONPs, Herceptin can kill the Herceptin-resistant cells equally effectively as it kills the Herceptin-sensitive cells under the hypoxic, but not normoxic, culture conditions by inhibiting the cell viability, survival and proliferation. Signaling analysis reveals that under the normoxic conditions, the levels of hypoxia induced factor 1α as well as vascular endothelial growth factor are higher in the Herceptin-resistant cells than that in the Herceptin-sensitive cells and are strongly induced once the culture is switched to the hypoxic conditions, which can be potently suppressed by CONPs. Treatment with CONPs plus Herceptin significantly slows down the primary tumor growth and lung metastasis of the Herceptin-resistant cells in a xenograft mouse model of orthotopic breast cancer through inhibiting the cell proliferation and survival as well as tumor angiogenesis. These results shed new lights on the mechanisms underlying the Herceptin resistance of the HER2⁺ breast cancer and provide insights into introducing CONPs-like agents to Herceptin-based therapy to improve treatment outcomes.

Nanoceria, the versatile nanoparticles: Promising biomedical applications

Nanotechnology has been a boon for the biomedical field due to the freedom it provides for tailoring of pharmacokinetic properties of different drug molecules. Nanomedicine is the medical application of nanotechnology for the diagnosis, treatment and/or management of the diseases. Cerium oxide nanoparticles (CNPs) are metal oxide-based nanoparticles (NPs) which possess outstanding reactive oxygen species (ROS) scavenging activities primarily due to the availability of "oxidation switch" on their surface. These NP have been found to protect from a number of disorders with a background of oxidative stress such as cancer, diabetes etc. In fact, the CNPs have been found to possess the environment-dependent ROS modulating properties. In addition, the inherent catalase, SOD, oxidase, peroxidase and phosphatase mimetic properties of CNPs provide them superiority over a number of NPs. Further, chemical reactivity of CNPs seems to be a function of their surface chemistry which can be precisely tuned by defect engineering. However, the contradictory reports make it necessary to critically evaluate the potential of CNPs, in the light of available literature. The review is aimed at probing the feasibility of CNPs to push towards the clinical studies. Further, we have also covered and censoriously discussed the suspected negative impacts of CNPs before making our way to a consensus. This review aims to be a comprehensive, authoritative, critical, and accessible review of general interest to the scientific community.

Metal-Mediated Nanoscale Cerium Oxide Inactivates Human Coronavirus and Rhinovirus by Surface Disruption

The COVID19 pandemic has brought global attention to the threat of emerging viruses and to antiviral therapies, in general. In particular, the high transmissibility and infectivity of respiratory viruses have been brought to the general public's attention, along with the need for highly effective antiviral and disinfectant materials/products. This study has developed two distinct silver-modified formulations of redox-active nanoscale cerium oxide (AgCNP1 and AgCNP2). The formulations show specific antiviral activities toward tested OC43 coronavirus and RV14 rhinovirus pathogens, with materials characterization demonstrating a chemically stable character for silver nanophases on ceria particles and significant differences in Ce3+/Ce4+ redox state ratio (25.8 and 53.7% Ce3+ for AgCNP1 & 2, respectively). In situ electrochemical studies further highlight differences in formulation-specific viral inactivation and suggest specific modes of action. Altogether, the results from this study support the utility of AgCNP formulations as high stability, high efficacy materials for use against clinically relevant virus species.

DNA-Modified Plasmonic Sensor for the Direct Detection of Virus Biomarkers from the Blood

The rapid spread of viral infections demands early detection strategies to minimize proliferation of the disease. Here, we demonstrate a plasmonic biosensor to detect Dengue virus, which was chosen as a model, via its nonstructural protein NS1 biomarker. The sensor is functionalized with a synthetic single-stranded DNA oligonucleotide and provides high affinity toward NS1 protein present in the virus genome. We demonstrate the detection of NS1 protein at a concentration of 0.1-10 μg/mL in bovine blood using an on-chip microfluidic plasma separator integrated with the plasmonic sensor which covers the clinical threshold of 0.6 μg/mL of high risk of developing Dengue hemorrhagic fever. The conceptual and practical demonstration shows the translation feasibility of these microfluidic optical biosensors for early detection of a wide range of viral infections, providing a rapid clinical diagnosis of infectious diseases directly from minimally processed biological samples at point of care locations.

Nanoparticle mediated RNA delivery for wound healing

Wound healing is a complicated physiological process that comprises various steps, including hemostasis, inflammation, proliferation, and remodeling. The wound healing process is significantly affected by coexisting disease states such as diabetes, immunosuppression, or vascular disease. It can also be impacted by age, repeated injury, or hypertrophic scarring. These comorbidities can affect the rate of wound closure, the quality of wound closure, and tissues' function at the affected sites. There are limited options to improve the rate or quality of wound healing, creating a significant unmet need. Advances in nucleic acid research and the human genome project have developed potential novel approaches to address these outstanding requirements. In particular, the use of microRNA, short hairpin RNA, and silencing RNA is unique in their abilities as key regulators within the physiologic machinery of the cell. Although this innovative therapeutic approach using ribonucleic acid (RNA) is an attractive approach, the application as a therapeutic remains a challenge due to site-specific delivery, off-target effects, and RNA degradation obstacles. An ideal delivery system is essential for successful gene delivery. An ideal delivery system should result in high bioactivity, inhibit rapid dilution, controlled release, allow specific activation timings facilitating physiological stability, and minimize multiple dosages. Currently, these goals can be achieved by inorganic nanoparticle (NP) (e.g., cerium oxide, gold, silica, etc.) based delivery systems. This review focuses on providing insight into the preeminent research carried out on various RNAs and their delivery through NPs for effective wound healing. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures.

High-throughput and versatile design for multi-layer coating deposition using lab automation through Arduino-controlled devices

Laboratory and experimental scale manufacturing processes are limited by human error (e.g., poor control over motion and personal subjectivity), especially under fatiguing conditions involving precise, repetitive operations, incurring compounding errors. Commercial layer-by-layer (LbL) automation devices are prohibitively high-priced (especially for academic institutions) with limited flexibility in form factor and potentially software-associated constraints/limitations. In this work, a novel automated multi-beaker dip coater was fabricated to facilitate nano cerium oxide/polymer coatings via an LbL dip coating process and the synthesis of nano ceria films via a novel successive ionic layer adsorption and reaction method on a glass substrate. Automation of tasks, such as those mediating the detailed procedures, is essential in producing highly reproducible, consistent products/materials as well as in reducing the time commitments for laboratory researchers. Herein, we detail the construction of a relatively large, yet inexpensive, LbL coating instrument that can operate over 90 cm in the horizontal axis, allowing, for example, up to eight 200 ml beakers with accompanying stir plates. The instrument is operated by simple "off-the-shelf" electronics to control the path and timing of the samples with open-source software while providing precision at ±0.01 mm. Furthermore, 3D-printed components were used to maximize the number of substrates that could be coated simultaneously, further improving the sample production rate and reducing waste. Further possibilities for automation beyond the detailed device are provided and discussed, including software interfaces, physical control methods, and sensors for data collection/analysis or for triggers of automated tasks.

Ameliorating hydroxychloroquine induced retinal toxicity through cerium oxide nanoparticle treatments

The present study investigated the potential protective effects of cerium oxide nanoparticles (CNP) on human retinal pigment epithelium (ARPE-19) cells damaged by hydroxychloroquine (HCQ). Toxicity of HCQ on the ARPE-19 cells was explored with a dose response trial. CNP rescue both a pre-treatment protocol, where CNP were applied 24 hours prior to HCQ application and a simultaneous treatment protocol where both CNP and HCQ were applied together, were used. In the dose response trial, 250 µM HCQ showed 51.84% cell viability after 24 hours and 32.75% after 48 hours time period. This was selected as model HCQ dose for rescue trials. The simultaneous treatment trials did not show a significant increase in viability compared to model toxic dose. The CNP pre-treatment trials showed a significant increase in cellular viability compared to model toxic dose with 68.03% ± 3.27 viability (p = 4.56E-05) at 24 hours and 51.85% ± 4.96 (p = 1.18E-05) at 48 hours time period. CNP pre-treatment showed significant protection of cells from HCQ induced toxicity. The difference in efficacy of simultaneous and pre-treatment is hypothesized to lie in the cellular localization of CNP. Furthermore, including the reactive oxygen species (ROS) scavenging properties of CNP seems to be responsible for protection, the effect of CNP on autophagosome and lysosome colocalization are also hypothesized to play a significant role.

Tomographic Study of Mesopore Formation in Ceria Nanorods

Porosity in functional oxide nanorods is a recently discovered new type of microstructure, which is not yet fully understood and still under evaluation for its impact on applications in catalysis and gas/ion storage. Here we explore the shape and distribution of pores in ceria in three dimensions using a modified algorithm of geometric tomography as a reliable tool for reconstructing defective and strained nanoobjects. The pores are confirmed as "negative-particle" or "inverse-particle" cuboctahedral shapes located exclusively beneath the flat surface of the rods separated via a sub-5 nm thin ceria wall from the outside. New findings also comprise elongated "negative-rod" defects, seen as embryonic nanotubes, and pores in cube-shaped ceria. Furthermore, we report near-sintering secondary heat treatment of nanorods and cubes, confirming persistence of pores beyond external surface rounding. We support our experiments with molecular modeling and predict that the growth history of voids is via diffusion and aggregation of atomic point defects. In addition, we use density functional theory to show that the relative stability of pore (shape) increases in the order "cuboidal" < "hexagonal-prismatic" < "octahedral". The results indicate that by engineering voids into nanorods, via a high-temperature postsynthetic heat treatment, a potential future alternative route of tuning catalytic activities might become possible.

Cerium oxide nanoparticles protect against irradiation-induced cellular damage while augmenting osteogenesis

Increased bone loss and risk of fracture are two of the main challenges for cancer patients who undergo ionizing radiation (IR) therapy. This decline in bone quality is in part, caused by the excessive and sustained release of reactive oxygen species (ROS). Cerium oxide nanoparticles (CeONPs) have proven antioxidant and regenerative properties and the purpose of this study was to investigate the effect of CeONPs in reducing IR-induced functional damage in human bone marrow-derived mesenchymal stromal cells (hBMSCs). hBMSCs were supplemented with CeONPs at a concentration of either 1 or 10 μg/mL 24 h prior to exposure to a single 7 Gy irradiation dose. ROS levels, cellular proliferation, morphology, senescence, DNA damage, p53 expression and autophagy were evaluated as well as alkaline phosphatase, osteogenic protein gene expression and bone matrix deposition following osteogenic differentiation. Results showed that supplementation of CeONPs at a concentration of 1 μg/mL reduced cell senescence and significantly augmented cell autophagy (p = 0.01), osteogenesis and bone matrix deposition >2-fold (p = 0.0001) while under normal, non-irradiated culture conditions. Following irradiation, functional damage was attenuated and CeONPs at both 1 or 10 μg/mL significantly reduced ROS levels (p = 0.05 and 0.001 respectively), DNA damage by >4-fold (p < 0.05) while increasing autophagy >3.5-fold and bone matrix deposition 5-fold (p = 0.0001 in both groups). When supplemented with 10 μg/mL, p53 expression increased 3.5-fold (p < 0.05). We conclude that cellular uptake of CeONPs offered a significant, multifunctional and protective effect against IR-induced cellular damage while also augmenting osteogenic differentiation and subsequent new bone deposition. The use of CeONPs holds promise as a novel multifunctional therapeutic strategy for irradiation-induced bone loss.

Cerium oxide nanomaterial with dual antioxidative scavenging potential: Synthesis and characterization

Many studies have linked reactive oxygen species (ROS) to various diseases. Biomedical research has therefore sought a way to control and regulate ROS produced in biological systems. In recent years, cerium oxide nanoparticles (nanoceria, CNPs) have been pursued due to their ability to act as regenerative ROS scavengers. In particular, they are shown to have either superoxide dismutase (SOD) or catalase mimetic (CAT) potential depending on the ratio of Ce³⁺/Ce⁴⁺ valence states. Moreover, it has been demonstrated that SOD mimetic activity can be diminished by the presence of phosphate, which can be a problem given that many biological systems operate in a phosphate-rich environment. Herein, we report a CNP formulation with both SOD and catalase mimetic activity that is preserved in a phosphate-rich media. Characterization demonstrated a highly dispersed, stable solution of uniform-sized, spherical-elliptical shaped CNP of 12 ± 2 nm, as determined through dynamic light scattering, zeta potential, and transmission electron microscopy. Mixed valence states of Ce ions were observed via UV/Visible spectroscopy and XPS (Ce³⁺/Ce⁴⁺ > 1) (Ce³⁺∼ 62%). X-ray diffraction and XPS confirmed the presence of oxygen-deficient cerium oxide (CeO_2-x) particles. Finally, the CNP demonstrated very good biocompatibility and efficient reduction of hydrogen peroxide under in-vitro conditions.

Multi-functional cerium oxide nanoparticles regulate inflammation and enhance osteogenesis

Oxidative stress increases bone loss and limits repair, in part, through immunoregulation and the formation and maintenance of low-grade chronic inflammation. The aim of this study was to investigate the effect of cerium oxide nanoparticles (CeONPs) on (i) macrophage phenotype and cytokine expression under normal and simulated acute and chronic inflammatory conditions and, (ii) human mesenchymal stem cell (hBMSCs) proliferation, osteoinduction and osteogenic differentiation. Spherical particles composed of 60% Ce³⁺ with a hydrodynamic size of ~35 nm and surface charge of 25.4 mV were internalized within cells. Under both acute and chronic conditions, inducible nitric oxide synthase (iNOS) activity decreased with a significant reduction seen in the 1 and 10 μg/mL groups (p < 0.001). A dose dependent and significant increase in anti-inflammatory cytokine gene expression was observed in all CeONP groups under chronic inflammatory condition. No increase in alkaline phosphatase (ALP) activity or mineral deposits were measured following hBMSCs cultured without osteogenic media in any of the CeONP groups, however, a significant increase in osteogenic-related gene expression, ALP activity and bone mineral deposits was measured when supplemented with both CeONPs and osteogenic media. CeONP activity was multifaceted and exhibited low toxicity. A therapeutic dose of 1 μg/mL delivered a disparate but protective effect when under both acute and chronic inflammatory conditions while at the same dose, potentiated osteogenesis.

Nanosilk Increases the Strength of Diabetic Skin and Delivers CNP-miR146a to Improve Wound Healing

Diabetes mellitus is a metabolic disorder associated with properties and an increased risk of chronic wounds due to sustained pro-inflammatory response. We have previously of radical scavenging cerium oxide nanoparticles (CNP) conjugated to the anti-inflammatory microRNA (miR)-146a, termed CNP-miR146a, improves diabetic wound healing by synergistically lowering oxidative stress and inflammation, and we sought to evaluate this treatment in a topical application. Silk fibroin is a biocompatible polymer that can be fabricated into nanostructures, termed nanosilk. Nanosilk is characterized by a high strength-to-density ratio and an ability to exhibit strain hardening. We therefore hypothesized that nanosilk would strengthen the biomechanical properties of diabetic skin and that nanosilk solution could effectively deliver CNP-miR146a to improve diabetic wound healing. The ability of nanosilk to deliver CNP-miR146a to murine diabetic wounds and improve healing was assessed by the rate of wound closure and inflammatory gene expression, as well as histologic analysis. The effect of nanosilk on the properties of human diabetic skin was evaluated by testing the biomechanical properties following topical application of a 7% nanosilk solution. Diabetic murine wounds treated with topical nanosilk and CNP-miR146a healed by day 14.5 compared to day 16.8 in controls (p = 0.0321). Wounds treated with CNP-miR146a had higher collagen levels than controls (p = 0.0126) with higher pro-fibrotic gene expression of TGFβ-1 (p = 0.0092), Col3α1 (p = 0.0369), and Col1α2 (p = 0.0454). Treatment with CNP-miR146a lowered pro-inflammatory gene expression of IL-6 (p = 0.0488) and IL-8 (p = 0.0009). Treatment of human diabetic skin with 7% nanosilk solution resulted in significant improvement in maximum load and modulus (p < 0.05). Nanosilk solution is able to strengthen the biomechanical properties of diabetic skin and can successfully deliver CNP-miR146a to improve diabetic wound healing through inhibition of pro-inflammatory gene signaling and promotion of pro-fibrotic processes.

Ceria Nanoparticles Decrease UVA-Induced Fibroblast Death Through Cell Redox Regulation Leading to Cell Survival, Migration and Proliferation

Exposure to ultraviolet radiation is a major contributor to premature skin aging and carcinogenesis, which is mainly driven by overproduction of reactive oxygen species (ROS). There is growing interest for research on new strategies that address photoaging prevention, such as the use of nanomaterials. Cerium oxide nanoparticles (nanoceria) show enzyme-like activity in scavenging ROS. Herein, our goal was to study whether under ultraviolet A rays (UVA)-induced oxidative redox imbalance, a low dose of nanoceria induces protective effects on cell survival, migration, and proliferation. Fibroblasts cells (L929) were pretreated with nanoceria (100 nM) and exposed to UVA radiation. Pretreatment of cells with nanoceria showed negligible cytotoxicity and protected cells from UVA-induced death. Nanoceria also inhibited ROS production immediately after irradiation and for up to 48 h and restored the superoxide dismutase (SOD) activity and GSH level. Additionally, the nanoceria pretreatment prevented apoptosis by decreasing Caspase 3/7 levels and the loss of mitochondrial membrane potential. Nanoceria significantly improved the cell survival migration and increased proliferation, over a 5 days period, as compared with UVA-irradiated cells, in wound healing assay. Furthermore, it was observed that nanoceria decreased cellular aging and ERK 1/2 phosphorylation. Our study suggests that nanoceria might be a potential ally to endogenous, antioxidant enzymes, and enhancing the redox potentials to fight against UVA-induced photodamage and consequently modulating the cells survival, migration, and proliferation.

Exposure to nanoceria impacts larval survival, life history traits and fecundity of Aedes aegypti

Effectively controlling vector mosquito populations while avoiding the development of resistance remains a prevalent and increasing obstacle to integrated vector management. Although, metallic nanoparticles have previously shown promise in controlling larval populations via mechanisms which are less likely to spur resistance, the impacts of such particles on life history traits and fecundity of mosquitoes are understudied. Herein, we investigate the chemically well-defined cerium oxide nanoparticles (CNPs) and silver-doped nanoceria (AgCNPs) for larvicidal potential and effects on life history traits and fecundity of Aedes (Ae.) aegypti mosquitoes. When 3rd instar larvae were exposed to nanoceria in absence of larval food, the mortality count disclosed significant activity of AgCNPs over CNPs (57.8±3.68% and 17.2±2.81% lethality, respectively) and a comparable activity to Ag+ controls (62.8±3.60% lethality). The surviving larvae showed altered life history traits (e.g., reduced egg hatch proportion and varied sex ratios), indicating activities of these nanoceria beyond just that of a larvicide. In a separate set of experiments, impacts on oocyte growth and egg generation resulting from nanoceria-laced blood meals were studied using confocal fluorescence microscopy revealing oocytes growth-arrest at 16-24h after feeding with AgCNP-blood meals in some mosquitoes, thereby significantly reducing average egg clutch. AgCNPs caused ~60% mortality in 3rd instar larvae when larval food was absent, while CNPs yielded only ~20% mortality which contrasts with a previous report on green-synthesized nanoceria and highlights the level of detail required to accurately report and interpret such studies. Additionally, AgCNPs are estimated to contain much less silver (0.22 parts per billion, ppb) than the amount of Ag+ needed to achieve comparable larvicidal activity (2.7 parts per million, ppm), potentially making these nanoceria ecofriendly. Finally, this work is the first study to demonstrate the until-now-unappreciated impacts of nanoceria on life history traits and interference with mosquito egg development.

Ceria Nanoparticles Mitigate the Iron Oxidative Toxicity of Human Retinal Pigment Epithelium

Oxidative injury is implicated in retinal damage observed in age-related macular degeneration (AMD), as well as other degenerative conditions. Abnormally elevated levels of iron accumulation within the retinal pigment epithelium have been detected in eyes with AMD, and it is suspected to play a role in the pathogenesis through the production of reactive oxygen species (ROS). Ceria nanoparticles (CNP) have the ability to scavenge ROS. This study sought to evaluate the ability of CNP to mitigate iron-induced oxidative stress and assess cell viability in the human ARPE-19 cell line in vitro. Cell viability was measured by an MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and compared between experimental groups undergoing 48-hr exposure to a ferrous iron solution with and without 24-hr CNP pre-treatment. The CNP effect on ROS formation was evaluated additionally by H2DCFDA (2,7-dichlorodihydrofluorescein diacetate) fluorescent probe assay and superoxide dismutase assay. CNP demonstrated a three-fold increase in cell viability and a reduction in ROS generation. The results show a promising treatment modality for diseases causing oxidative damage in the eye.

Ultra-high arsenic adsorption by graphene oxide iron nanohybrid: Removal mechanisms and potential applications

Iron (Fe)-based adsorbents have been promoted for aqueous arsenic adsorption because of their low cost and potential ease of scale-up in production. However, their field application is, so far, limited because of their low Fe use efficiency (i.e., not all available Fe is used), slow adsorption kinetics, and low adsorption capacity. In this study, we synthesized graphene oxide iron nanohybrid (GFeN) by decorating iron/iron oxide (Fe/Fe_xO_y) core-shell structured iron nanoparticles (FeNPs) on the surface of graphene oxide (GO) via a sol-gel process. The deposition of FeNPs on GO for the nanohybrid (GFeN) improves Fe use efficiency and arsenic mobility in the nanohybrid, thereby improving the arsenic removal capacity and kinetics. We achieved removal capacities of 306 mg/g for As(III) and 431 mg/g for As(V) using GFeN. Rapid reduction (>99% in <10 min) of As(III) and As(V) (initial concentration, C₀ = 100 μg/L) was achieved with the nanohybrid (250 mg/L). There were no significant interferences by the coexisting anions and organic matters at environmentally relevant concentrations. Based on the experimental data, we have proposed that both electrostatic interaction and surface complexation contributed to ultra-high arsenic removal by GFeN. The GO sheets acted as the reservoirs for the electrons released during surface corrosion of the FeNPs and the electrons were transferred back to the FeNPs to rejuvenate the oxidized surface. The rejuvenated FeNP surface layer helped in additional arsenic removal.

Engineered defects in cerium oxides: tuning chemical reactivity for biomedical, environmental, & energy applications

Nanocrystalline cerium oxide (nanoceria) is a rare earth oxide with a complex surface chemistry. This material has seen substantial investigation in recent years in both fundamental and applied studies due largely to more precise characterization of the unique surface structures, which mediate its pronounced redox activity. In particular, oxygen storage/buffering capacities have been thoroughly correlated with synthesis and processing condition effects on other material features such as surface (micro-) faceting, reconstruction, and (extent of) hydration. Key material features such as these modulate nanoceria redox performance by changing the crystal microenvironment. In this review, we present nanoengineering methods, which have produced increased nanoceria performance in biomedical, energy, and catalysis applications. The impact of combined/cooperative theoretical and experimental studies are highlighted throughout.

Silk fibroin nanofibrous mats for visible sensing of oxidative stress in cutaneous wounds

Amplex red infused silk mats in visible detection of oxidative stress in the cutaneous wound over time.

Injectable, self-healable zwitterionic cryogels with sustained microRNA - cerium oxide nanoparticle release promote accelerated wound healing

Diabetics are prone to chronic wounds that have slower healing, and methods of accelerating the wound closure and to ensure protection from infections are critically needed. MicroRNA-146a gets dysregulated in diabetic wounds and injection of this microRNA combined with reactive oxygen species-scavenging cerium oxide nanoparticles (CNPs) can reduce inflammation and improve wound healing; however, a better delivery method than intradermal injections is needed. Here we demonstrate a biomaterial system of zwitterionic cryogels (gels formed below freezing temperatures) laden with CNP-miR146a that are topically applicable, injectable, self-healable, and provide sustained release of the therapeutic molecules. These cryogels are comprised of CBMA or SBMA and HEMA, and do not contain chemical crosslinkers. Properties of the gels can be manipulated by changing monomer type and ratio. These materials have demonstrated efficacy and viability in vivo with a diabetic mouse wound healing model. Overall, these materials have a high potential for application in wound treatments due to their ease of production, antifouling characteristics, durability, topical application, and sustained release mechanics. STATEMENT OF SIGNIFICANCE: This work presents the development of zwitterionic cryogels with unique physical properties including injectability and self-healing, that also offer highly sustained release of nanoparticles over time to improve wound healing in a diabetic mouse model. The nanoparticles are made of cerium oxide, which is known to scavenge reactive oxygen species and reduce oxidative stress, and these particles have been further tagged with a microRNA146a that has been shown to reduce inflammation. Zwitterionic materials are known for their superior antifouling properties and good biocompatibility and ability to incorporate bioactive factors. Given these properties, the use of these materials as wound healing dressings would be exciting, yet to date it has been difficult to prolong the release of bioactive factors from them due to their hydrophilicity. Previously we developed zwitterionic cyrogels with very sustained protein release over time, but those materials were quite brittle and difficult to handle. Here, we demonstrate for the first time that by removing the crosslinker molecule from our reaction and polymerizing gels under cryo-conditions, we are able to form zwitterionic cryogels that are injectable, self-healing, and with sustained release profiles. The sustained release of miRNA146a-tagged cerium oxide nanoparticles from these gels is demonstrated to speed up diabetic wound healing time and significantly reduce inflammation.