Competition at the Bio-nano Interface: A Protein, a Polysaccharide, and a Fatty Acid Adsorb onto Magnetic Nanoparticles.

Magnetic nanoparticles are an attractive bioseparation tool due to their magnetic susceptibility and high adsorption capacity for different types of molecules. A major challenge for separation is to generate selectivity for a target molecule, or for a group of molecules in complex environments such as cell lysates. It is crucial to understand the factors that determine the targets' adsorption behavior in mixtures for triggering intended interactions and selectivity. Here we use a model system containing three molecules, each of them a common representative of the more abundant types of macromolecules in living systems: sodium oleate (SO), a fatty acid; bovine serum albumin (BSA), a protein; and dextran, a polysaccharide. Our results show that (a) the BSA adsorption capacity on the iron oxide material depends markedly on the pH, with the maximum capacity at the pI of the protein (0.39 g gMNP-1 ); (b) sodium oleate, a strongly negatively charged molecule, an organic anion, renders a maximum adsorption capacity of 0.40 g gMNP-1, even at pHs at which oleate as well as the nanoparticle surface are negatively charged; (c) the adsorbed masses of dextran, a neutral sugar, are lower than for the other two molecules, between 0.09 and 0.13 g gMNP-1, regardless of the system's pH. We observe an unexpected behavior in mixtures: SO completely prevents the adsorption of BSA, and dextran decreases the adsorption of the other competitors, SO and BSA, while adsorbing at the same capacities, unaffected by either the presence of the other two molecules or the pH. BSA does not decrease the oleate adsorption capacity. We demonstrate the essential role of pH in the adsorption of BSA (a protein) and SO (a fatty acid), as well as its impact in the structural organization of the oleate molecules in water. Moreover, we present exciting data on the adsorption of the molecules in competition, revealing the need to focus on interaction studies in more complex environments. This study attempts to open the scope of the current research of bio-nano interactions to not only proteins but also to mixtures, and generally to molecules with other physicochemical characteristics. Furthermore, we contribute to the understanding of multicomponent systems with the vision set in enhancing biomass exploitation and biofractionation processes.

Bio-nano interactions: binding proteins, polysaccharides, lipids and nucleic acids onto magnetic nanoparticles.

The major interest in nanoparticles as an application platform for biotechnology arises from their high surface-to-volume ratio. Iron oxide nanoparticles (IONPs) are particularly appealing due to their superparamagnetic behavior, which enables bioseparation using external magnetic fields. In order to design advanced biomaterials, improve binding capacities and develop innovative processing solutions, a thorough understanding of the factors governing organic-inorganic binding in solution is critical but has not yet been achieved, given the wide variety of chemical and physical influences. This paper offers a critical review of experimental studies of the interactions between low cost IONPs (bare iron oxides, silica-coated or easily-functionalized surfaces) and the main groups of biomolecules: proteins, lipids, nucleic acids and carbohydrates. Special attention is devoted to the driving forces and interdependencies responsible of interactions at the solid-liquid interface, to the unique structural characteristics of each biomolecular class, and to environmental conditions influencing adsorption. Furthermore, studies focusing on mixtures, which are still rare, but absolutely necessary to understand the biocorona, are also included. This review concludes with a discussion of future work needed to fill the gaps in knowledge of bio-nano interactions, seeking to improve nanoparticles' targeting capabilities in complex systems, and to open the door for multipurpose recognition and bioseparation processes.

The Benefits and Challenges of Managing Asthma in Hispanic Families in South Texas: A Mixed-Methods Study.

BACKGROUND: Understanding the experience of Hispanic parents of children diagnosed with asthma can be useful in the delivery of effective and meaningful asthma education. In order to assess the needs of Hispanic families with asthmatic children in South Texas, investigators utilized a combination of qualitative and quantitative research methods. OBJECTIVES: This study aimed (1) to assess the impact of asthma in the quality of life of Hispanic children and their families and (2) to identify barriers and challenges to asthma management as perceived by parents of children diagnosed with asthma. METHODS: A mixed-methods study included a quality-of-life survey and focus group discussions. The Children's Health Survey for Asthma (CHSA) was completed by 90 parents of children with asthma. Three focus groups were conducted with 15 low-income, Hispanic parents of asthmatic children to assess their needs and experience in managing the disease. RESULTS: Results from the CHSA showed that asthma significantly affects the quality of life of children with asthma and their families, particularly the emotional dimensions and the child's physical health. Fifty-three percent of the children had visited the emergency room, and 51% had been hospitalized due to asthma. One out of five parents had missed work, and 27% of children had missed school in the past 2 weeks due to the child's asthma. In the focus group discussions, the key themes emerging included lack of asthma knowledge, the burden of disease for asthmatic children and their families, and the importance of asthma education and self-management behaviors for asthma control. CONCLUSION: One of the main challenges faced by Hispanic families with asthmatic children is the lack of asthma-related knowledge to help understand and control their children's disease. Lack of knowledge and self-management skills lead to significant stress and anxiety among children with asthma and their parents. Results highlight that while asthma has an effect on the quality of life of children and their families, particularly on the emotional health domain, a wide dissemination of asthma management education in different settings might help prevent asthma attacks and improve symptom control among those suffering from this disease along the US-Mexico border.