A general method for the immobilization of cells with preserved viability

Nilsson, Karin; Birnbaum, Staffan; Flygare, Susanne; Linse, L.; Schröder, Ulf; Jeppsson, Ulla; Larsson, Per‐Olof; Mosbach, Klaus; Brodelius, Peter E.

doi:10.1007/bf00499497

Cited by 147 publications

(40 citation statements)

References 17 publications

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“…For in vivo NMR measurements, D. salina was trapped inside agarose beads using a modification of the two-phase procedure of Nilsson et al [16]. A 6% solution of low-temperature-gelling agarose (Sigma Chemical Co.) in growth medium was prepared, and equilibrated at 37 "C. Algae at the logarithmic phase of growth (lo6 to 2.5 x lo6 cells/ml) were concentrated by centrifugation at room temperature (2000 x g for 10 min).…”

Section: Preparation Of Cells For the N M R Experimentsmentioning

confidence: 99%

Metabolic studies with NMR spectroscopy of the alga Dunaliella salina trapped within agarose beads

Bental

Pick

Avron

et al. 1990

European Journal of Biochemistry

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A technique for the entrapment of the unicellular algae Dunaliella salina in agarose beads and their perfusion during NMR measurements is presented. The trapped cells maintained their ability to proliferate under normal growth conditions, and remained viable and stable under steady-state conditions for long periods during NMR measurements. Following osmotic shock in the dark, prominent changes were observed in the intracellular level of ATP and polyphosphates, but little to no changes in the intracellular pH or orthoposphate content. When cells were subjected to hyperosmotic shock, the ATP level decreased. The content of NMR-visible polyphosphates decreased as well, presumably due to the production of longer, NMR-invisible structures. Following hypoosmotic shock, the ATP content increased and longer polyphosphates were broken down to shorter, more mobile polymers.Dunaliella (Volvocales, Chlorophyceae) is a unicellular, motile green alga, which lacks a rigid cell wall. Dunaliella has the capacity to adapt to a wide range of salt concentrations (0.1 -5.5 M NaCl), adjusting to the extracellular osmotic pressure by accumulating glycerol as an osmolyte and compatible solute. At constant salinity, the turnover rate of the glycerol pool is relatively slow [l]. When subjected to a hypoosmotic or hyperosmotic shock, the cells react within seconds like osmometers, swelling or shrinking, respectively, due to very rapid water fluxes. This is followed by a metabolic phase, which lasts about two hours, during which the cell carries out massive glycerol synthesis or elimination [2] in order to regain its original volume. It was established that the main immediate carbon source for glycerol production in the light (and the only one in the dark), and the end product of the glycerol elimination process is starch [3, 41. A cycle of glycerol metabolism has been proposed [5, 61, but the initial signal triggering glycerol metabolism and the control points of glycerol -starch interconversion are not yet resolved.NMR techniques were recently employed in studies aimed at understanding the mechanism of osmoregulation and its control. Such techniques monitor intracellular components in vivo, non-invasively and in real time. Living Dunaliella cells were studied using 31P, I3C and 23Na NMR [7-131. In vivo NMR techniques require very high cell densities for obtaining a good signal-to-noise ratio within a reasonable time. Means must therefore be developed to maintain such high cell densities under conditions which closely simulate normal growth conditions. This can be achieved by trapping of the cells and continuous perfusion with fresh medium of a controlled composition. Perfusion also permits the study of the response of the cells to changes in the extracellular environment in real time, without removing the cells from the cavity of the NMR .magnet.

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Section: Preparation Of Cells For the N M R Experimentsmentioning

confidence: 99%

Metabolic studies with NMR spectroscopy of the alga Dunaliella salina trapped within agarose beads

Bental

Pick

Avron

et al. 1990

European Journal of Biochemistry

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“…Matrices used for entrapment can be synthetic polymers, such as polyester, or natural polymers, such as agar, agarose, or alginate [27]. Entrapment allows to preserve and prolong cell viability, for example, during storage [26,27], which matched the intentions of this work.…”

Section: Immobilization Of Sensor Cellsmentioning

confidence: 66%

“…An established technique for immobilization of living cells is entrapment, which refers to the physical containment of organisms inside a matrix or fibers, thus creating a protective barrier around the cells [27]. Matrices used for entrapment can be synthetic polymers, such as polyester, or natural polymers, such as agar, agarose, or alginate [27].…”

Section: Immobilization Of Sensor Cellsmentioning

confidence: 99%

Development of a Modular Biosensor System for Rapid Pathogen Detection

Hanke¹,

Bailly²,

Demling³

et al. 2018

Biosensing Technologies for the Detection of Pathogens - A Prospective Way for Rapid Analysis

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Progress in the field of pathogen detection relies on at least one of the following three qualities: selectivity, speed, and cost-effectiveness. Here, we demonstrate a proof of concept for an optical biosensing system for the detection of the opportunistic human pathogen Pseudomonas aeruginosa while addressing the abovementioned traits through a modular design. The biosensor detects pathogen-specific quorum sensing molecules and generates a fluorescence signal via an intracellular amplifier. Using a tailored measurement device built from low-cost components, the image analysis software detected the presence of P. aeruginosa in 42 min of incubation. Due to its modular design, individual components can be optimized or modified to specifically detect a variety of different pathogens. This biosensor system represents a successful integration of synthetic biology with software and hardware engineering.

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“…Spherical gelbeads were formed without agglomeration and exhibited rubber like properties. Agar-agar and agarose entrapment of cells was carried out following the methods of Nilsson et al (1983) and Manolov et al (1995). Samples (19 ml) of polymer solutions (2 % agar-agar and 4 % agarose) were mixed with 0.75 g wet biomass at 45ºC and extruded into an oil phase (paraffin oil).…”

Section: Preparation Of Immobilized Cellsmentioning

confidence: 99%