Solid-phase cell immobilization

Due to the increased application of MoAbs in diagnostics and therapeutics, considerable effort has been made to develop technology for the large-scale production of MoAbs. Examples of the currently employed culture systems are hollow-fiber systems, suspensions, solid-phase cell immobilization, perfusion reactor, and encapsulation... 

These reactors contain suspended solid particles. A discontinuous gas phase is sparged into the reactor. Coal liquefaction is an example where the solid is consumed by the reaction. The three phases are hydrogen, a hydrocarbon-solvent/ product mixture, and solid coal. Microbial cells immobilized on a particulate substrate are an example of a three-phase system where the slurried phase is catalytic. The liquid phase is water that contains the organic substrate. The gas phase supplies oxygen and removes carbon dioxide. The solid phase consists of microbial cells grown on the surface of a nonconsumable solid such as activated carbon. 

The deprotected lactosides were evaluated as inhibitors against lectin binding in a solid-phase inhibition assay with immobilized ASF on the surface of microtiter plate wells, mimicking cell-surface presentation, while mammalian galectins-1, -3, and -5 were in solution. Strong multivalency effects and selectivity were observed for the... 

Figure 3 Schematic diagram of a solid-phase N02 sensor. The sensor consists of a small cell supporting the polymer-coated, glass substrate behind a glass window in full view of a PMT. The CL reagent is immobilized on the hydrogel substrate. The gel is sandwiched between the glass window and a Teflon PTFE membrane. The purpose of the Teflon membrane is to permit the diffusion of N02 from the airstream into the gel while preventing the loss of water from the hydrogel. Inlet and outlet tubes (PTFE) allow a vacuum pump to sample air (2 L/min) directly across the surface of the chemical sensor. (Adapted with permission from Ref. 12.)...

Almost all modern practical aqueous primaries are referred to as dry cells . This designation should not be confused with the rather specialized solid state cells which make use of the recently discovered true solid electrolytes. Rather, the term implies that the aqueous electrolyte phase has been immobilized by the use of gelling agents or by incorporation into microporous separators. Such procedures permit the cells to operate in any orientation and reduce the effects of leakage should the container become punctured. 

A liquid-phase resistance inside a dispersed solid phase such as cell floes, immobilized enzymes, etc. 

Three-phase fluidized beds can be used as bioreactors for aerobic biochemical processes, including both fermentation processes and wastewater treatment. The gas phase is air, required for biological growth, while the solid particles provide immobilized surfaces on or in which cell growth can occur. The aqueous liquid phase provides the culture medium needed for the growth and maintenance of the cells. Air may be introduced separately from the liquid, or be premixed with the aqueous medium. The liquid medium may exhibit non-Newtonian rheology. A disadvantage of three-phase... 

A variety of non-mammalian (l-4)GalTs are widely distributed in Nature. For example, a cell free extract from S. hygroscopicus has been used to galacto-sylate macrolide antibiotics [69]. Notably, a number of solid-phase galactosyla-tions of immobilized substrates have also been probed successfully [70-72]. 

Fast blot methods to minimize nucleic acid extraction and immobilization steps have been developed. Those with nylon as a solid phase can take advantage of the ability of NaOH to dissociate cells, denature DNA and immobilize DNA. Nitrocellulose membranes have a lower binding capacity and co-immobilization of nucleic acid and protein from neutral solutions can be a problem. Bresser et al. (1983) used hot concentrated Nal to inhibit protein immobilization, to denature DNA and to irreversibly bind the nucleic acid to nitrocellulose (no baking required). This method can also be used for RNA. About 10 cells are minimally required for a unique DNA sequence, whereas > 0.01% of total mRNA can be detected by the Nal methods. 

It is generally agreed among the practitioners of whole beer processing that product removal in the presence of cells is more difficult to attain, and requires that all physico-chemical parameters of the operation such as fermentation medium composition to be standardized. The purpose of this paper is to describe a new approach to achieve whole broth processing using immobilized solid phase adsorbents. 

Affinity Selection of Cells on Solid-Phase Matrices with Immobilized Proteins... 

This paper reviews the present status of affinity separation of cells based on the biospecific interaction of cellular receptors with proteinaceous ligands immobilized on a solid-phase matrix. Special emphasis was placed on the development of new matrix materials for immuno-affinity chromatography of lymphocyte subpopulations. Our newly developed matrix of poly(2-hydroxyethyl methacrylate)/polyamine graft copolymer offered novel advantages in (1) elimination of non-specific adsorption of lymphocytes and (2) simple immobilization procedure of ligand protein through non-covalent adsorption. This matrix allowed a rapid separation of preparative quantities of pure and vital lymphocyte subpopulations (IgG-positive and -negative cells) in excellent yield. 

In spite of the widespread utilization of affinity chromatography in cell separation, there are still a considerable number of problems to be solved. The most serious problem is that there is always a substantial fraction of cells that are non-specifically adsorbed on the matrix surface. The research on cell affinity chromatography done in the last decade seems to be more biased towards the improvement in operating conditions than to the development of specially designed matrices for cell separation as well as the characterization of immobilized proteins. Nevertheless, there is no doubt that further advances in affinity chromatography as an effective tool for cell separation virtually depend on the detailed understanding of the features of matrix materials and immobilized proteins, as well as their interacions at the interface. In this respect, cell affinity selection based on the specific interaction of cells with immobilized proteins on a solid-phase matrix is now a major area of interest in the field of biomaterials science. 

As briefly reviewed in this paper, affinity selection of cells using proteinaceous ligands immobilized on solid-phase matrices is a subject which requires detailed understanding of the nature of proteins at interface as well as the mode of their interaction with living cells. In this sense, this is surely a promising frontier which presents a strong challenge to researchers in the biomaterials field. 

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