Oxygen-generating microparticles downregulate HIF-1α expression, increase cardiac contractility, and mitigate ischemic injury.

Myocardial hypoxia is the low oxygen tension in the heart tissue implicated in many diseases, including ischemia, cardiac dysfunction, or after heart procurement for transplantation. Oxygen-generating microparticles have recently emerged as a potential strategy for supplying oxygen to sustain cell survival, growth, and tissue functionality in hypoxia. Here, we prepared oxygen-generating microparticles with poly D,L-lactic-co-glycolic acid, and calcium peroxide (CPO), which yielded a continuous morphology capable of sustained oxygen release for up to 24 h. We demonstrated that CPO microparticles increased primary rat cardiomyocyte metabolic activity while not affecting cell viability during hypoxia. Moreover, hypoxia-inducible factor (HIF)-1α, which is upregulated during hypoxia, can be downregulated by delivering oxygen using CPO microparticles. Single-cell traction force microscopy data demonstrated that the reduced energy generated by hypoxic cells could be restored using CPO microparticles. We engineered cardiac tissues that showed higher contractility in the presence of CPO microparticles compared to hypoxic cells. Finally, we observed reduced myocardial injuries in ex vivo rabbit hearts treated with CPO microparticles. In contrast, an acute early myocardial injury was observed for the hearts treated with control saline solution in hypoxia. In conclusion, CPO microparticles improved cell and tissue contractility and gene expression while reducing hypoxia-induced myocardial injuries in the heart. STATEMENT OF SIGNIFICANCE: Oxygen-releasing microparticles can reduce myocardial ischemia, allograft rejection, or irregular heartbeats after heart transplantation. Here we present biodegradable oxygen-releasing microparticles that are capable of sustained oxygen release for more than 24 hrs. We then studied the impact of sustained oxygen release from microparticles on gene expresseion and cardiac cell and tissue function. Previous studies have not measured cardiac tissue or cell mechanics during hypoxia, which is important for understanding proper cardiac function and beating. Using traction force microscopy and an engineered tissue-on-a-chip, we demonstrated that our oxygen-releasing microparticles improve cell and tissue contractility during hypoxia while downregulating the HIF-1α expression level. Finally, using the microparticles, we showed reduced myocardial injuries in rabbit heart tissue, confirming the potential of the particles to be used for organ transplantation or tissue engineering.

Micro and Nanoscale Technologies for Diagnosis of Viral Infections.

Viral infection is one of the leading causes of mortality worldwide. The growth of globalization significantly increases the risk of virus spreading, making it a global threat to future public health. In particular, the ongoing coronavirus disease 2019 (COVID-19) pandemic outbreak emphasizes the importance of devices and methods for rapid, sensitive, and cost-effective diagnosis of viral infections in the early stages by which their quick and global spread can be controlled. Micro and nanoscale technologies have attracted tremendous attention in recent years for a variety of medical and biological applications, especially in developing diagnostic platforms for rapid and accurate detection of viral diseases. This review addresses advances of microneedles, microchip-based integrated platforms, and nano- and microparticles for sampling, sample processing, enrichment, amplification, and detection of viral particles and antigens related to the diagnosis of viral diseases. Additionally, methods for the fabrication of microchip-based devices and commercially used devices are described. Finally, challenges and prospects on the development of micro and nanotechnologies for the early diagnosis of viral diseases are highlighted.

Micro and nanoscale technologies in oral drug delivery.

Oral administration is a pillar of the pharmaceutical industry and yet it remains challenging to administer hydrophilic therapeutics by the oral route. Smart and controlled oral drug delivery could bypass the physiological barriers that limit the oral delivery of these therapeutics. Micro- and nanoscale technologies, with an unprecedented ability to create, control, and measure micro- or nanoenvironments, have found tremendous applications in biology and medicine. In particular, significant advances have been made in using these technologies for oral drug delivery. In this review, we briefly describe biological barriers to oral drug delivery and micro and nanoscale fabrication technologies. Micro and nanoscale drug carriers fabricated using these technologies, including bioadhesives, microparticles, micropatches, and nanoparticles, are described. Other applications of micro and nanoscale technologies are discussed, including fabrication of devices and tissue engineering models to precisely control or assess oral drug delivery in vivo and in vitro, respectively. Strategies to advance translation of micro and nanotechnologies into clinical trials for oral drug delivery are mentioned. Finally, challenges and future prospects on further integration of micro and nanoscale technologies with oral drug delivery systems are highlighted.

3D Bioprinting of Oxygenated Cell-Laden Gelatin Methacryloyl Constructs.

Cell survival during the early stages of transplantation and before new blood vessels formation is a major challenge in translational applications of 3D bioprinted tissues. Supplementing oxygen (O2 ) to transplanted cells via an O2 generating source such as calcium peroxide (CPO) is an attractive approach to ensure cell viability. Calcium peroxide also produces calcium hydroxide that reduces the viscosity of bioinks, which is a limiting factor for bioprinting. Therefore, adapting this solution into 3D bioprinting is of significant importance. In this study, a gelatin methacryloyl (GelMA) bioink that is optimized in terms of pH and viscosity is developed. The improved rheological properties lead to the production of a robust bioink suitable for 3D bioprinting and controlled O2 release. In addition, O2 release, bioprinting conditions, and mechanical performance of hydrogels having different CPO concentrations are characterized. As a proof of concept study, fibroblasts and cardiomyocytes are bioprinted using CPO containing GelMA bioink. Viability and metabolic activity of printed cells are checked after 7 days of culture under hypoxic condition. The results show that the addition of CPO improves the metabolic activity and viability of cells in bioprinted constructs under hypoxic condition.

Imaging and Targeting of the α(2-6) and α(2-3) Linked Sialic Acid Quantum Dots in Zebrafish and Mouse Models.

Sialic acid-conjugated nanocarriers have emerged as attractive biomarkers with promising biomedical applications. The translation of these nanocarriers into clinical applications requires in-depth assessment in animal models. However, due to the complexity, ethical concerns, and cost of the high-order animal system, there is an immediate need of information-rich simple animal models to decipher the biological significance. Herein, we performed in vivo head-to-head comparison of Neu5Acα(2-6) and α(2-3)Gal conjugated quantum dots (QDs) toxicity, biodistribution, and sequestration in wild-type zebrafish ( Danio rerio) and mouse model (C57BL). The fluorescent properties and cadmium composition of quantum dots were used to map the blood clearance, biodistribution, and sequestration of the sialylated QDs in major organs of both models. We observed that α(2-6) sialylated QDs preferentially have prolonged circulating half-life and broader biodistribution in both models. On the contrary, α(2-3) sialic acid and galactose-conjugated QDs have shortened blood circulation time and are sequestered in the liver, and cleared after several hours in both models. These results demonstrate the applicability of the zebrafish and sialylated QDs to target specific organs, as well as drug delivery and biomedical diagnostics.

Modeling Glyco-Collagen Conjugates Using a Host-Guest Strategy To Alter Phenotypic Cell Migration and in Vivo Wound Healing.

The constructs and study of combinatorial libraries of structurally defined homologous extracellular matrix (ECM) glycopeptides can significantly accelerate the identification of cell surface markers involved in a variety of physiological and pathological processes. Herein, we present a simple and reliable host-guest approach to design a high-throughput glyco-collagen library to modulate the primary and secondary cell line migration process. 4-Amidoadamantyl-substituted collagen peptides and ß-cyclodextrin appended with mono- or disaccharides were used to construct self-assembled glyco-collagen conjugates (GCCs), which were found to be thermally stable, with triple-helix structures and nanoneedles-like morphologies that altered cell migration processes. We also investigated the glycopeptide's mechanisms of action, which included interactions with integrins and cell signaling kinases. Finally, we report murine wound models to demonstrate the real-time application of GCCs. As a result of our observations, we claim that the host-guest model of ECM glycopeptides offers an effective tool to expedite identification of specific glycopeptides to manipulate cell morphogenesis, cell differentiation metastatic processes, and their biomedical applications.

Exploring the Influence of Shapes and Heterogeneity of Glyco-Gold Nanoparticles on Bacterial Binding for Preventing Infections.

To investigate the effects of the heterogeneity and shape of glyco-nanoprobes on carbohydrate-protein interactions (CPIs), α-d-mannose- and ß-d-galactose-linked homo- and heterogeneous glycodendrons were synthesized and immobilized on spherical and rod-shaped gold nanoparticles (AuNPs). Lectin and bacterial binding studies of these glyco-AuNPs clearly illustrate that multivalency and shape of AuNPs contribute significantly to CPIs than the heterogeneity of glycodendrons. Finally, bacterial infection of HeLa cells was effectively inhibited by the homogeneous glycodendron-conjugated rod-shaped AuNPs relative to their heterogeneous counterparts. Overall, these results provide insight into the role of AuNP shape and multivalency as potential factors to regulate CPIs.

Mapping the Glyco-Gold Nanoparticles of Different Shapes Toxicity, Biodistribution and Sequestration in Adult Zebrafish.

Glyconanotechnology offers a broad range of applications across basic and translation research. Despite the tremendous progress in glyco-nanomaterials, there is still a huge gap between the basic research and therapeutic applications of these molecules. It has been reported that complexity and the synthetic challenges in glycans synthesis, the cost of the high order in vivo models and large amount of sample consumptions limited the effort to translate the glyco-nanomaterials into clinical applications. In this regards, several promising simple animal models for preliminary, quick analysis of the nanomaterials activities has been proposed. Herein, we have studied a systematic evaluation of the toxicity, biodistribution of fluorescently tagged PEG and mannose-capped gold nanoparticles (AuNPs) of three different shapes (sphere, rod, and star) in the adult zebrafish model, which could accelerate and provide preliminary results for further experiments in the higher order animal system. ICP-MS analysis and confocal images of various zebrafish organs revealed that rod-AuNPs exhibited the fast uptake. While, star-AuNPs displayed prolong sequestration, demonstrating its potential therapeutic efficacy in drug delivery.

Understanding carbohydrate-protein interactions using homologous supramolecular chiral Ru(ii)-glyconanoclusters.

Multivalent glycodendrimers make promising tools to tackle the basic and translational research in the field of carbohydrate-mediated interactions. Despite advances in glycodendrimers and glycopolymers, the multivalent probes available to date are still far from being ideal biological mimics. This work demonstrates the inherent chirality of glycodendrimers to be one of the promising factors to generate different spatial carbohydrate micro-environments to modulate specific carbohydrate-protein interactions. By exploiting the host-guest strategy, chiral Ru(ii) complexes (Δ and Λ) and mannose capped ß-cyclodextrin (ß-CD), we generated a library of homologous metallo-glycodendrimers (MGDs) with sizes of 50-70 nm. These nanoclusters can enantioselectively bind to specific C-type lectins and displayed selectivity in cellular uptake. We also discovered their potential clathrin-mediated endocytotic pathway in DC-SIGN and SIGNR3-transfected cell lines. Finally, in vivo biodistribution and sequestration of MGDs was determined to understand the role of chirality mediated spatial arrangement in carbohydrate-mediated interactions.

Correction: Supramolecular metalloglycodendrimers selectively modulate lectin binding and delivery of Ru(ii) complexes into mammalian cells.

Correction for 'Supramolecular metalloglycodendrimers selectively modulate lectin binding and delivery of Ru(ii) complexes into mammalian cells' by Harikrishna Bavireddi, et al., Org. Biomol. Chem., 2016, DOI: 10.1039/c6ob01546h.

Supramolecular metalloglycodendrimers selectively modulate lectin binding and delivery of Ru(ii) complexes into mammalian cells.

A host-guest interaction between Ru(ii)-complexes and sugar-capped ß-cyclodextrin was employed to synthesize metalloglycodendrimers. These glycodendrimers demonstrated selective carbohydrate-protein interactions and controlled the delivery of the Ru(ii) complexes into cancer cells, which may facilitate cell-specific apoptosis. Lectin binding assay revealed micromolar range IC50 values with different plant lectins. Cell viability assay and confocal imaging studies of Ru(ii) complexes exhibited cytotoxic activities in cancer cells compared to normal cells with IC50 values close to other literature Ru(ii) complexes. The cell death inducer was found to accumulate favorably to the endoplasmic reticulum (ER) and induced ER stress in cells. The upregulation of CHOP, caspase-3 and caspase-12 disturbed the ER morphology initiating the apoptosis pathway.

Glyco-gold nanoparticle shapes enhance carbohydrate-protein interactions in mammalian cells.

Advances in shape-dependent nanoparticle (NP) research have prompted a close scrutiny of the behaviour of nanostructures in vitro and in vivo. Data pertaining to cellular uptake and site specific sequestration of different shapes of NPs will undoubtedly assist researchers to design better nano-probes for therapeutic and imaging purposes. Herein, we investigated the shape dependent uptake of glyco-gold nanoparticles (G-AuNPs) in different cancer cell lines. Specifically, we have compared the behaviour of spherical, rod and star AuNPs with mannose and galactose conjugations. In vitro experiments showed that the rod-AuNPs exhibited the highest uptake over that of the star and spherical counterparts. Further, an investigation of the mechanism of the uptake clearly demonstrated clathrin mediated endocytosis of the specific G-AuNPs. These results reveal the benefits of different G-AuNP shapes in carbohydrate-mediated interactions.

Effect of Transition Metals on Polysialic Acid Structure and Functions.

Polysialic acid (PSA) is one of the most abundant glycopolymer present in embryonic brain, and it is known to be involved in key roles such as plasticity in the central nervous system, cell adhesion, migration and localization of neurotrophins. However, in adult brain, its expression is quite low. The exception to this is in Alzheimer's disease (AD) brain, where significantly increased levels of polysilylated neural cell adhesion molecule (PSA-NCAM) have been reported. Here, we confirm the role of PSA as a metal chelator, allowing it to decrease cytotoxicity caused by high levels of transition metals, commonly found in AD brain, and as a regulator of cell behavior. UV-visible (UV-vis) and circular dichroism (CD) spectroscopy, atomic force microscopy (AFM), and isothermal titration calorimetry (ITC) techniques were used to investigate the assembly of PSA-metals complexes. These PSA-metal complexes exhibited less toxicity compared to free metal ions, and in particular, the PSA-Cu(2+) complex synergistically promoted neurite outgrowth in PC12 cells.

Immobilization of multivalent glycoprobes on gold surfaces for sensing proteins and macrophages.

The multivalent display of carbohydrates on the cell surface provides cooperative binding to improve the specific biological events. In addition to multivalency, the spatial arrangement and orientation of sugars with respect to external stimuli also trigger carbohydrate-protein interactions. Herein, we report a non-covalent host-guest strategy to immobilize heptavalent glyco-ß-cyclodextrin on gold-coated glass slides to study multivalent carbohydrate-protein interactions. We have found that the localization of sugar entities on surfaces using ß-cyclodextrin (ß-CD) chemistry increased the avidity of carbohydrate-protein and carbohydrate-macrophage interactions compared to monovalent-ß-CD sugar coated surfaces. This platform is expected to be a promising tool to amplify the avidity of sugar-mediated interactions on surfaces and contribute to the development of next generation bio-medical products.

Assessing the effect of different shapes of glyco-gold nanoparticles on bacterial adhesion and infections.

Achieving selective and sensitive carbohydrate-protein interactions (CPIs) using nanotechnology is an intriguing area of research. Here we demonstrate that the different shapes of gold nanoparticles (AuNPs) functionalized with monosaccharides tune the bacterial aggregations. The mechanism of aggregation revealed that the large number of surface interactions of rod shaped mannose-AuNPs with E. coli ORN 178 compared with spherical and star-shaped AuNPs exhibited higher avidity and sensitivity. Moreover, such sensitive binding can be used for effective inhibition of bacterial infection of cells.