Arctic Art & Culture

The popular science review includes the materials about educational, research, scientific and practical activity of the team from the Arctic State Institute of Culture and Arts, their partners, and the Northern Forum regions facilitating the modern image-making of the North and Arctic

Arctic Art & Culture

The popular science journal includes the materials about educational, research, scientific and practical activity of the team from the Arctic State Institute of Culture and Arts and the Northern Forum regions facilitating the image-making of the North and Arctic

Polyelectrolyte-Clay-Protein Layer Films on Microfluidic PDMS Bioreactor Surfaces for Primary Murine Bone Marrow Culture

Poly(dimethylsiloxane) (PDMS) microbioreactors with computerized perfusion controls would be useful for engineering the bone marrow microenvironment. However, previous efforts to grow primary bone marrow cells on PDMS substrates have not been successful due to the weak attachment of cells to the PDMS surface even with adsorption of cell adhesive proteins such as collagen or fibronectin. In this work, modification of the surface of PDMS with biofunctional multilayer coatings is shown to promote marrow cell attachment and spreading. An automated microfluidic perfusion system is used to create multiple types of polyelectrolyte nanoscale coatings simultaneously in multiple channels based on layer-by-layer deposition of PDDA (poly(diallyldimethyl ammonium chloride)), clay, type IV collagen and fibronectin. Adherent primary bone marrow cells attached and spread best on a surface with composition of (PDDA/clay) 5 (Collagen/Fibronectin) 2 with negatively charged fibronectin exposed on the top, remaining well spread and proliferating for at least two weeks. Compared to traditional more macroscopic layer-by-layer methods, this microfluidic nanocomposite process has advantages of greater flow control, automatic processing, multiplexed fabrication, and use of lesser amounts of polymers and protein solutions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57408/1/2701_ftp.pd

Freely Suspended Cellular “Backpacks” Lead to Cell Aggregate Self-Assembly

Cellular “backpacks” are a new type of anisotropic, nanoscale thickness microparticle that may be attached to the surface of living cells creating a “bio-hybrid” material. Previous work has shown that these backpacks do not impair cell viability or native functions such as migration in a B and T cell line, respectively. In the current work, we show that backpacks, when added to a cell suspension, assemble cells into aggregates of reproducible size. We investigate the efficiency of backpack−cell binding using flow cytometry and laser diffraction, examine the influence of backpack diameter on aggregate size, and show that even when cell−backpack complexes are forced through small pores, backpacks are not removed from the surfaces of cells.National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (Award DMR-08-19762)National Science Foundation (U.S.) (Graduate Research Fellowship)United States. Dept. of DefenseUnited States. Air Force Office of Scientific ResearchHoward Hughes Medical Institute (Investigator)United States. Dept. of Defense (National Defense Science and Engineering Graduate Fellowship 32 CFR 168a

A “cell-friendly” window for the interaction of cells with hyaluronic acid/poly-L-lysine multilayers

Polyelectrolyte multilayers assembled from hyaluronic acid (HA) and poly-L-lysine (PLL) are most widely studied showing excellent reservoir characteristics to host molecules of diverse nature; however, thick (HA/PLL)n films were often found cell-repellent. By a systematic study of the adhesion and proliferation of various cells as a function of bilayer number ‘n’ a correlation with the mechanical and chemical properties of films is developed. The following cell lines have been studied: mouse 3T3 and L929 fibroblasts, human foreskin primary fibroblasts VH-Fib, human embryonic kidney HEK-293, human bone cell line U-2-OS, Chinese hamster ovary CHO-K and mouse embryonic stem cells. All cells adhere and spread well in a narrow ‘cell-friendly’ window, identified in the range of n=12-15. At n15, the film is cell-repellent for all cell lines. Cellular adhesion correlates with the mechanical properties of the films showing that softer films at higher ‘n’ number exhibiting a significant decrease of the Young’s modulus below 100 kPa are weakly adherent to cells. This trend cannot be reversed even by coating a strong cell-adhesive protein fibronectin onto the film. This indicates that mechanical cues plays a major role for cell behaviour, also in respect to biochemical ones

Thermoresponsive UCST-Type Behavior of Interpolymer Complexes of Poly(ethylene glycol) and Poly(poly(ethylene glycol) methacrylate) Brushes with Poly(acrylic acid) in Isopropanol

Upper critical solution temperature (UCST)-type thermoresponsive behavior of poly(ethylene glycol)-poly(acrylic acid) (PEG-PAA) and poly(poly(ethylene glycol) methacrylate)-poly(acrylic acid) (PPEGMA-PAA) interpolymer complexes has been observed in isopropanol. For these investigations, PPEGMA and PAA with various average molecular weights have been synthesized by atom transfer radical polymerization. It has been found that both the PEG and PPEGMA have lower cloud point temperatures (Tcp) than its mixed polymer solutions with PAA, whereas PAA does not show such behavior in the investigated temperature range. These findings indicate the reversible formation of interpolymer complexes with variable structure and composition in the solutions of the polymer mixtures in isopropanol. Increasing the ethylene glycol/acrylic acid molar ratio or the molecular weight of either the PAA or the H-acceptor PEG component of the interpolymer complexes increases the UCST-type cloud point temperatures of these interpolymer systems. The polymer-polymer interactions by hydrogen bonds between PAA and PEG or PPEGMA and the correlations between Tcp and structural parameters of the components revealed in the course of these investigations may be utilized for exploring well-defined UCST-type material systems for various applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim