Combinatorial High-Throughput Screening of Complex Polymeric Enzyme Immobilization Supports.

Recent advances have demonstrated the promise of complex multicomponent polymeric supports to enable supra-biological enzyme performance. However, the discovery of such supports has been limited by time-consuming, low-throughput synthesis and screening. Here, we describe a novel combinatorial and high-throughput platform that enables rapid screening of complex and heterogeneous copolymer brushes as enzyme immobilization supports, named combinatorial high-throughput enzyme support screening (CHESS). Using a 384-well plate format, we synthesized arrays of three-component polymer brushes in the microwells using photoactivated surface-initiated polymerization and immobilized enzymes in situ. The utility of CHESS to identify optimal immobilization supports under thermally and chemically denaturing conditions was demonstrated usingBacillus subtilisLipase A (LipA). The identification of supports with optimal compositions was validated by immobilizing LipA on polymer-brush-modified biocatalyst particles. We further demonstrated that CHESS could be used to predict the optimal composition of polymer brushes a priori for the previously unexplored enzyme, alkaline phosphatase (AlkP). Our findings demonstrate that CHESS represents a predictable and reliable platform for dramatically accelerating the search of chemical compositions for immobilization supports and further facilitates the discovery of biocompatible and stabilizing materials.

Supra-biological performance of immobilized enzymes enabled by chaperone-like specific non-covalent interactions.

Designing complex synthetic materials for enzyme immobilization could unlock the utility of biocatalysis in extreme environments. Inspired by biology, we investigate the use of random copolymer brushes as dynamic immobilization supports that enable supra-biological catalytic performance of immobilized enzymes. This is demonstrated by immobilizing Bacillus subtilis Lipase A on brushes doped with aromatic moieties, which can interact with the lipase through multiple non-covalent interactions. Incorporation of aromatic groups leads to a 50 °C increase in the optimal temperature of lipase, as well as a 50-fold enhancement in enzyme activity. Single-molecule FRET studies reveal that these supports act as biomimetic chaperones by promoting enzyme refolding and stabilizing the enzyme's folded and catalytically active state. This effect is diminished when aromatic residues are mutated out, suggesting the importance of π-stacking and π-cation interactions for stabilization. Our results underscore how unexplored enzyme-support interactions may enable uncharted opportunities for using enzymes in industrial biotransformations.

Spatial predictors of heavy metal concentrations in epiphytic moss samples in Seattle, WA.

The use of bio-indicators is an emerging, cost-effective alternative approach to identifying air pollution and assessing the need for additional air monitoring. This community science project explores the use of moss samples as bio-indicators of the distribution of metal air particulates in two residential neighborhoods of the industrial Duwamish Valley located in Seattle, WA (USA). We applied geographically weighted regression to data from 61 youth-collected samples to assess the location-specific area-level spatial predictors of the concentrations of 25 elements with focus on five heavy metals of concern due to health and environmental considerations. Spatial predictors included traffic volume, industrial land uses, major roadways, the airport, dirt roads, the Duwamish River, impervious surfaces, tree canopy cover, and sociodemographics. Traffic volume surrounding sample locations was the most consistent positive predictor of increasing heavy metal concentration. Greater distance from the heavy-industry corridor surrounding the Duwamish River predicted lower concentrations of all metals, with statistically significant associations for chromium and lead in some areas. As the distance from dirt roads increased, the concentration of arsenic and chromium decreased significantly. Percent tree canopy within 200 m of sample locations was a significant protective factor for cadmium concentrations. In addition, percent people of color was significantly positively associated with increasing lead, chromium and nickel concentrations. Our findings underscore the potential influence of heavy industry and mobile sources on heavy metal concentrations, the buffering potential of trees in local environments, and persistent opportunity to improve environmental justice.

Understanding Design Rules for Optimizing the Interface between Immobilized Enzymes and Random Copolymer Brushes.

A long-standing goal in the field of biotechnology is to develop and understand design rules for the stabilization of enzymes upon immobilization to materials. While immobilization has sometimes been successful as a strategy to stabilize enzymes, the design of synthetic materials that stabilize enzymes remains largely empirical. We sought to overcome this challenge by investigating the mechanistic basis for the stabilization of immobilized lipases on random copolymer brush surfaces comprised of poly(ethylene glycol) methacrylate (PEGMA) and sulfobetaine methacrylate (SBMA), which represent novel heterogeneous supports for immobilized enzymes. Using several related but structurally diverse lipases, including Bacillus subtilis lipase A (LipA), Rhizomucor miehei lipase, Candida rugosa lipase, and Candida antarctica lipase B (CALB), we showed that the stability of each lipase at elevated temperatures was strongly dependent on the fraction of PEGMA in the brush layer. This dependence was explained by developing and applying a new algorithm to quantify protein surface hydrophobicity, which involved using unsupervised cluster analysis to identify clusters of hydrophobic atoms. Characterization of the lipases showed that the optimal brush composition correlated with the free energy of solvation per enzyme surface area, which ranged from -17.1 kJ/mol·nm2 for LipA to -11.8 kJ/mol·nm2 for CALB. Additionally, using this algorithm, we found that hydrophobic patches consisting of aliphatic residues had a higher free energy than patches consisting of aromatic residues. By providing the basis for rationally tuning the interface between enzymes and materials, this understanding will transform the use of materials to reliably ruggedize enzymes under extreme conditions.

Estatus de la vitamina D en sepsis en la Unidad Cuidados Intensivos Adultos / Vitamin D status in sepsis in the Adult Intensive Care Unit / Status da vitamina D na sepse na Unidade de Terapia Intensiva Adulto

Resumen: Introducción: En la actualidad se ha dado gran importancia al estudio de vitaminas C en sepsis. Sin embargo, especialmente en el contexto de cuidados intensivos, existe evidencia limitada, pero significativa de la elevada prevalencia de la deficiencia de vitamina D en los enfermos con sepsis y choque séptico correlacionándose con la gravedad y la probabilidad de disfunción orgánica. Material y métodos: Estudio retrospectivo, monocéntrico, observacional y descriptivo, muestra a conveniencia en un hospital de tercer nivel. Se analizó un total de 492 pacientes, de los cuales 105 cursaron con el diagnóstico de sepsis, de éstos, 30 contaron con medición de vitamina D. La edad media fue de 56 años, con predominio del sexo masculino (70%), antecedentes de patología oncológica (26.7%) e inmunosupresión (30%). Al ingreso a la unidad de cuidados intensivos 73.3% se encontraron en estado de choque, 70% bajo ventilación mecánica, con un promedio en las escalas de mortalidad de 16 puntos en APACHE II con 25% de mortalidad de ocho puntos en SOFA con 15-20% de mortalidad. De acuerdo con los niveles de vitamina D, se encontraron dos grupos: insuficiencia (menor de 10 ng/mL) y deficiencia (mayor de 10 ng/mL). Resultados: No se observó diferencia significativa en edad (p = 0.724), estancia intrahospitalaria (p = 0.755), SOFA (p = 0.241). Existe significancia estadística en APACHE II con un puntaje medio de 19.5 puntos en el grupo menor de 10 ng/mL (mortalidad esperada de 25%) y de 14.3 puntos en el grupo mayor de 10 ng/mL (mortalidad esperada de 15%). La mortalidad se estima en 42.9% en el grupo menor de 10 y de 12.5 en el grupo mayor de 10, pero no es significativo estadísticamente. Conclusiones: No existe correlación con un valor estadísticamente significativo entre los niveles de vitamina D y días de estancia intrahospitalaria. El porcentaje de defunción de los pacientes con valor inferior a 10 ng/mL fue de 42.9% a diferencia de los pacientes con valor superior a 10 ng/mL de 12.5%, que no alcanza un valor estadísticamente significativo; sin embargo, la población estudiada es reducida, por lo que sólo se requiere aumentar el tamaño de muestra para obtener un valor estadísticamente significativo.

Abstract: Introduction: Nowadays, Vitamin C research in sepsis has been of great importance. However, and especially in the critical care setting, there's limited but significant evidence about the high prevalence of vitamin D deficiency in sepsis and septic shock patients; correlating with the severity and the organ dysfunction risk. Material and methods: Retrospective study, monocentric, observational and descriptive, sample taken by convenience. 492 patients were analyzed, which 105 had sepsis diagnosis, and 30 of these patients had vitamin D quantification. The median age was 56 years, predominantly male (70%), the main medical history were oncologic illness, immunosuppression. At the time of intensive care unit admission 73.3% were in shock state, 70% on mechanical ventilation, with a mean mortality score of 16 points (APACHE II score, 25% mortality risk), and 8 points in the SOFA score (15-20% mortality risk. According with the vitamin D levels, 2 groups were found: Insufficiency (less than 10 ng/mL) and deficiency (more than 10 ng/mL). Results: There was no significant age difference (p = 0.724), length of stay difference (p = 0.755), SOFA (p = 0.241). There is statistically significance on the APACHE II scores, with a mean score of 19.5 points in the less than 10 ng/mL group (mortality risk 25%), and 14.5 points in the greater than 10 ng/mL group (mortality risk 15%). Mortality estimation was 42.9% in the less than 10 ng/mL group, and 12.5% in the greater than 10 ng/mL group, however, this was not statistically significant data. Conclusions: There is no statistically significant correlation between vitamin D levels and hospital length of stay. Mortality was higher in patients with vitamin D levels lesser than 10 ng/mL (42.9%), and 12.5% mortality in those with levels greater than 10 ng/mL. However the study sample is small, it will be necessary to increase the number of patients in order to obtain more statistically significant data.

Resumo: Introdução: Atualmente, grande importância tem sido dada ao estudo da Vitamina C na sepse. No entanto, especialmente no contexto de terapia intensiva, há evidências limitadas, mas significativas, da alta prevalência de deficiência de vitamina D em pacientes com sepse e choque séptico, correlacionando-se com a gravidade e probabilidade de disfunção orgânica. Material e métodos: Estudo retrospectivo, monocêntrico, observacional e descritivo, amostra de conveniência em hospital terciário. Foram analisados 492 pacientes, dos quais 105 tinham diagnóstico de sepse, dos quais 30 tinham dosagem de vitamina D. A média de idade foi de 56 anos, predominantemente do sexo masculino (70%), história de patologia oncológica (26.7%) e imunossupressão (30%). Na admissão na unidade de terapia intensiva, 73.3% estavam em choque, 70% em ventilação mecânica, com mortalidade média de 16 pontos no APACHE II com mortalidade de 25% de 8 pontos no SOFA com mortalidade de 15-20%. De acordo com os níveis de vitamina D, foram encontrados 2 grupos: Insuficiência (menor que 10 ng/mL) e deficiência (maior que 10 n/mL). Resultados: Nenhuma diferença significativa foi encontrada para idade (p = 0.724), tempo de internação (p = 0.755), SOFA (p = 0.241). Há significância estatística no APACHE II com escore médio de 19.5 pontos no grupo menor a 10 ng/mL (mortalidade esperada de 25%) e de 14.3 pontos no grupo maior a 10 ng/mL (mortalidade esperada de 15%). A mortalidade é estimada em 42.9% no grupo com menor a 10 e 12.5 no grupo maior, mas não é estatisticamente significativa. Conclusões: Não há correlação com valor estatisticamente significativo entre os níveis de vitamina D e os dias de internação. O percentual de óbito de pacientes com valor menor que 10 ng/mL sendo 42.9%, ao contrário de pacientes com valor maior que 10 ng/mL de 12.5%, que não atinge valor estatisticamente significativo, porém a população estudada é pequena, portanto, basta aumentar o tamanho da amostra para obter um valor estatisticamente significativo.

Oxime Cross-Linked Alginate Hydrogels with Tunable Stress Relaxation.

Stress relaxation is an important design parameter of biomaterials that can provide an artificial microenvironment mimicking natural extracellular matrix (ECM). Here, we report a novel hydrogel platform based on sodium alginate (NaAlg) with tunable stress relaxation. We first developed a new synthesis route to introduce alkoxyamine functional groups into the alginate polymer backbone. By mixing the resulting polymer (NaAlg-AA) with aldehyde-containing oxidized alginate (NaAlg-Ald), oxime cross-linked alginate hydrogels were prepared. We demonstrate that highly tunable stress relaxation and mechanical properties can be achieved by systematically varying the composition (concentration, polymer mixing ratios, degree of oxidation of NaAlg-Ald) or environmental factors (pH, temperature, and use of catalyst). Combined with the natural capability of the alginate to be cross-linked by divalent cations, the developed hydrogel formations possess the unique capability of dual cross-linking mechanisms with different gelation kinetics. We demonstrated that this dual cross-linking capability can (i) be utilized for the creation of hydrogels in microbead or microthread geometries and (ii) be useful for biomedical applications that require both the fast encapsulation of cells in hydrogels (fast calcium cross-linking) and the provision of controlled viscoelastic environments to cultured cells for an extended period (durable oxime cross-linking). With biocompatibility confirmed by the culture of a B-cell line encapsulated within the developed hydrogel, this novel hydrogel platform provides a good prospect in various applications where stress relaxation plays a key role in cell-matrix interactions.

Skin Bleaching Among African and Afro-Caribbean Women in New York City: Primary Findings from a P30 Pilot Study.

INTRODUCTION: The application of skin bleaching products to inhibit melanogenesis is a common practice within the African diaspora. Despite the adverse health effects of skin bleaching, rigorous studies investigating skin bleaching behavior among these populations in the United States are limited. In our P30 pilot study, we explored predictors of skin bleaching practice intensity among African and Afro-Caribbean women. METHODS: In collaboration with our Community Engagement Core, we conducted a cross-sectional study to investigate the relationship between demographic and psychosocial predictors and skin-bleaching-related practice patterns among African and Afro-Caribbean women in New York City. RESULTS: Among the 76 participants recruited, the median age at the initiation of skin bleaching was 19.5 (16-25) years, yielding a median duration of 13.5 (6-23) years. Although pregnant women were not actively recruited for the study, 13.2% (n = 10) of the participants used skin bleaching products while pregnant or possibly breastfeeding. Nativeness and education were associated with various components of skin bleaching practice intensity, including duration of skin bleaching, daily use of products, and bleaching of the entire body. Participants' perceived skin-color-related quality of life was not associated with skin bleaching practice intensity. CONCLUSION: Skin bleaching is a habitual practice that likely requires culturally sensitive interventions to promote behavioral change. The existence of prenatal and postnatal exposure to mercury, hydroquinone, and other potentially harmful chemicals in skin bleaching products highlights an urgent need to explore the adverse effects of skin bleaching practices on birth outcomes and the growth and neurodevelopment of young babies.