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Cartilage degeneration or damage treatment is still a challenge, but, tissue engineering strategies, which combine cell therapy strategies, which combine cell therapy and scaffolds, and have emerged as a promising new approach. In this regard, polyurethanes and polyacrylates polymers have been shown to have clinical potential to treat osteochondral injuries. Here, we have used polymer microarrays technology to screen 380 different polyurethanes and polyacrylates polymers. The top polymers with potential to maintain chondrocyte viability were selected, with scale-up studies performed to evaluate their ability to support chondrocyte proliferation during long-term culture, while maintaining their characteristic phenotype. Among the selected polymers, poly (methylmethacrylate-co-methacrylic acid), showed the highest level of chondrogenic potential and was used to create a 3D hydrogel. Ultrastructural morphology, microstructure and mechanical testing of this novel hydrogel revealed robust characteristics to support chondrocyte growth. Furthermore, in vitro and in vivo biological assays demonstrated that chondrocytes cultured on the hydrogel had the capacity to produce extracellular matrix similar to hyaline cartilage, as shown by increased expression of collagen type II, aggrecan and Sox9, and the reduced expression of the fibrotic marker's collagen type I. In conclusion, hydrogels generated from poly (methylmethacrylate-co-methacrylic acid) created the appropriate niche for chondrocyte growth and phenotype maintenance and might be an optimal candidate for cartilage tissue-engineering applications. SIGNIFICANCE STATEMENT: Articular cartilage has limited self-repair ability due to its avascular nature, therefore tissue engineering strategies have emerged as a promising new approach. Synthetic polymers displaygreat potential and are widely used in the clinical setting. In our study, using the polymer microarray technique a novel type of synthetic polyacrylate was identified, that was converted into hydrogels for articular cartilage regeneration studies. The hydrogel based on poly (methylmethacrylate-co-methacrylic acid-co-PEG-diacrylate) had a controlable ultrastructural morphology, microstructure (porosity) and mechanical properties (stiffness) appropriate for cartilage engineering. Our hydrogel created the optimal niche for chondrocyte growth and phenotype maintenance for long-term culture, producing a hyaline-like cartilage extracellular matrix. We propose that this novel polyacrylate hydrogel could be an appropriate support to help in the treatment efficient cartilage regeneration.

Drug-Induced Liver Injury (DILI) is a potentially fatal adverse event and a leading cause for pre- and post-marketing drug withdrawal. Several multinational DILI initiatives have now rec- ommended a panel of protein and microRNA (miRNA) biomarkers that can detect early liver injury and inform about mechanistic basis. This manuscript describes the development of seqCOMBO, a unique combo-multiplexed assay which combines the dynamic chemical labelling approach and an antibody dependant method on Luminex MAGPIX system. SeqCOMBO enables a versatile multi- plexing platform to perform qualitative and quantitative analysis of proteins and miRNAs in patient serum samples simultaneously. To the best of our knowledge, this is the first method to profile protein and miRNA biomarkers to diagnose DILI in a single step assay.

Circulating microRNAs are biomarkers reported to be stable and translational across species. MicroRNA-122 (miR-122) is a hepatocyte-specific microRNA biomarker for drug-induced liver injury (DILI). We developed a single molecule, dynamic chemical labeling (DCL) assay to directly detect miR-122 in blood. The DCL assay specifically measured miR-122 directly from 10 μL of serum or plasma without any extraction steps, with a limit of detection of 1.32 pM that enabled the identification of DILI. Testing of 192 human serum samples showed that DCL accurately identified patients at risk of DILI after acetaminophen overdose (area under ROC curve 0.98 (95% CI; 0.96-1), P

Decellularized vascular scaffolds are promising materials for vessel replacements. However, despite the natural origin of decellularized vessels, issues such as biomechanical incompatibility, immunogenicity risks and the hazards of thrombus formation, still need to be addressed. In this study, we coated decellularized vessels obtained from porcine carotid arteries with poly (ethylmethacrylate-co-diethylaminoethylacrylate) (8g7) with the purpose of improving endothelial coverage and minimizing platelet attachment while enhancing the mechanical properties of the decellularized vascular scaffolds. The polymer facilitated binding of endothelial cells (ECs) with high affinity and also induced endothelial cell capillary tube formation. In addition, platelets showed reduced adhesion on the polymer under flow conditions. Moreover, the coating of the decellularized arteries improved biomechanical properties by increasing its tensile strength and load. In addition, after 5 days in culture, ECs seeded on the luminal surface of 8g7-coated decellularized arteries showed good regeneration of the endothelium. Overall, this study shows that polymer coating of decellularized vessels provides a new strategy to improve re-endothelialization of vascular grafts, maintaining or enhancing mechanical properties while reducing the risk of thrombogenesis. These results could have potential applications in improving tissue-engineered vascular grafts for cardiovascular therapies with small caliber vessels.

Faithfully recapitulating human physiology “in a dish” from a renewable source remains a holy grail for medicine and pharma. Many procedures have been described that, to a limited extent, exhibit human tissue-specific function in vitro. In particular, incomplete cellular differentiation and/or the loss of cell phenotype postdifferentiation play a major part in this void. We have developed an interdisciplinary approach to address this problem, using skill sets in cell biology, materials chemistry, and pharmacology. Pluripotent stem cells were differentiated to hepatocytes before being replated onto a synthetic surface. Our approach yielded metabolically active hepatocyte populations that displayed stable function for more than 2 weeks in vitro. Although metabolic activity was an important indication of cell utility, the accurate prediction of cellular toxicity in response to specific pharmacological compounds represented our goal. Therefore, detailed analysis of hepatocellular toxicity was performed in response to a custom-built and well-defined compound set and compared with primary human hepatocytes. Importantly, stem cell-derived hepatocytes displayed equivalence to primary human material. Moreover, we demonstrated that our approach was capable of modeling metabolic differences observed in the population. In conclusion, we report that pluripotent stem cell-derived hepatocytes will model toxicity predictably and in a manner comparable to current gold standard assays, representing a major advance in the field.

Maintaining stable differentiated somatic cell function in culture is essential to a range of biological endeavors. However, current technologies, employing, for example, primary hepatic cell culture (essential to the development of a bio-artificial liver and improved drug and toxicology testing), are limited by supply, expense, and functional instability even on biological cell culture substrata. As such, novel biologically active substrates manufacturable to GMP standards have the potential to improve cell culture-based assay applications. Currently hepatic endoderm (HE) generated from pluripotent stem cells is a genotypically diverse, cheap, and stable source of “hepatocytes”; however, HE routine applications are limited due to phenotypic instability in culture. Therefore a manufacturable subcellular matrix capable of supporting long-term differentiated cell function would represent a step forward in developing scalable and phenotypically stable hESC-derived hepatocytes. Adopting an unbiased approach we screened polymer microarrays and identified a polyurethane matrix which promoted HE viability, hepatocellular gene expression, drug-inducible metabolism, and function. Moreover, the polyurethane supported, when coated on a clinically approved bio-artificial liver matrix, long-term hepatocyte function and growth. In conclusion, our data suggest that an unbiased screening approach can identify cell culture substrate(s) that enhance the phenotypic stability of primary and stem cell-derived cell resources.

Polymer microarrays provide an innovative approach to identify materials with novel bacterial binding or repellent properties which could subsequently be used in a variety of practical applications. Here, we report a polymer microarray screen of hundreds of synthetic polymers to identify those which either selectively capture the major food-borne pathogen, Salmonella enterica serovar Typhimurium (S. Typhimurium), or prevent its binding. A parallel study with a lab strain of Escherichia coli (E. coli) is also reported; revealing polymers which either display a common binding activity or which exhibit species discrimination. Moreover, substrates were also uncovered which showed no binding of either organism, even when cultured at high density. The correlation between polymer structure and microbial-modulating behaviour was analysed further, while SEM analysis allowed visualization of the detailed interactions between surface and bacteria. Such polymers offer many new opportunities for bacterial enrichment or surface repulsion, in cleaning materials, as surface coatings for use in the food production industry or as a "bacterial scavenger" resin.

Traumatic brain injury (TBI) is the one of the most common forms of head trauma, and it remains a leading cause of death and disability. It is known that the initial mechanical axonal injury triggers a complex cascade of neuroinflammatory and metabolic events, the understanding of which is essential for clinical, translational, and pharmacological research. These can occur even in mild TBI, and are associated with several post-concussion manifestations, including transiently heightened vulnerability to a second insult. Recent studies have challenged the tenet that ischemia is the ultimate modality of tissue damage following TBI, as metabolic dysfunction can develop in the presence of normal perfusion and before intracranial hypertension. In order to elucidate the cellular and molecular changes occurring in TBI as a direct result of neuronal injury and in the absence of ischemic damage, we performed a microarray analysis of expressed genes and molecular interaction pathways for different levels of severity of trauma using an in-vitro model. A stretch injury, equivalent to human diffuse axonal injury, was delivered to rat organotypic hippocampal slice cultures, and mRNA levels following a 10% (mild) and 50% (severe) stretch were compared with controls at 24 h. More genes were differentially expressed following 10% stretch than 50% stretch, indicating the early activation of complex cellular mechanisms. The data revealed remarkable differential gene expression following mTBI, even in the absence of cell damage. Pathway analysis revealed that molecular interactions in both levels of injury were similar, with IL-1beta playing a central role. Additional pathways of neurodegeneration involving RhoA (ras homolog gene family, member A) were found in 50% stretch.

Engineered nanoparticles (eNPs) for biological and biomedical applications are produced from functionalised nanoparticles (NPs) after undergoing multiple handling steps, giving rise to an inevitable loss of NPs. Herein we present a practical method to quantify nanoparticles (NPs) number per volume in an aqueous suspension using standard spectrophotometers and minute amounts of the suspensions (up to 1 μL). This method allows, for the first time, to analyse cellular uptake by reporting NPs number added per cell, as opposed to current methods which are related to solid content (w/V) of NPs. In analogy to the parameter used in viral infective assays (multiplicity of infection), we propose to name this novel parameter as multiplicity of nanofection., JJDM thanks Spanish Ministerio de Economía y Competitividad for a Ramon y Cajal Fellowship and for supporting this work partially by Grant CTQ2012-34778. This research was partially supported by Marie Curie Career Integration Grants within the 7th European Community Framework Programme (FP7-PEOPLE-2011-CIG-Project Number 294142 and FP7-PEOPLE-2012-CIG-Project Number 322276) to RMSM and JJDM, respectively. This research was partially supported by the Consejería de Economía, Innovación y Ciencia de la Junta de Andalucía (BIO-1778) to JJDM. RMSM and JDUB thank CEI Biotic Granada for funding P_BS_54 and mP_BS_37 projects. JDUB thanks Spanish Ministerio de Economía y Competitividad for a Torres Quevedo fellowship (PTQ-13-06046).

Endothelial progenitor cells (EPCs) are a small population capable of self-renewal which participate actively in vasculogenesis, angiogenesis and arteriogenesis. Blood-derived EPCs or bone marrow (BM)-derived stem cells feature several drawbacks as far as their clinical utility is concerned, such as the extremely small number of circulating EPCs in the bloodstream and the low availability and harvesting difficulties of BM-derived stem cells. In contrast, human adipose-derived stem cells (hASCs) can be isolated in a greater number through a safe non-invasive liposuction procedure. We have developed a new approach of easy-to-derive large number of multipotent endothelial-like cells (ME-LCs) from human adipose tissue in culture for long periods. ME-LCs displayed increased expression levels of endothelial and hematopoietic lineage markers and EPC markers. Moreover, they formed tube-like structures when grown on 2-D coated MatrigelTM surfaces, secreted increased levels of SDF-1 and showed the ability to migrate attracted by cytokines. Importantly, ME-LCs retained the capacity to differentiate into cardiomyocyte-like cells.

Rapid endothelisation is of critical importance in the prevention of adverse remodelling after device implantation. Currently, there is a need for alternative strategies to promote re-endothelialisation for intravascular stents and vascular grafts. Using polymer microarray technology 345 polymers are comprehensively assessed and a matrix is identified that specifically supports both progenitor and mature endothelial cell activity in vitro and in vivo while minimising platelet attachment.

The liver is a highly resilient organ that possesses enormous regenerative capacity. This is mediated mainly through the most abundant cell type found in the liver, the hepatocyte. When the regenerative capacity of the hepatocyte is compromised, during chronic or acute liver injury, hepatic progenitor cells (HPCs) are activated to replace the damaged tissue. The HPC resides in a laminin-rich environment; as HPCs differentiate toward a hepatic or biliary fate, the extracellular matrix (ECM) composition changes, influencing cell behavior. To assess the impact that the biological ECM and the synthetic ECM have on the maintenance of hepatic stem cell gene expression, a murine hepatic stem cell line was employed. We demonstrate that hepatic stem cell gene expression could be maintained using a biological or synthetic substratum, but not on plastic alone.