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At least 19 recordsLinked to original sources
PubMed1998

Artificial cells with emphasis on cell encapsulation of genetically engineered cells.

Artificial cells are prepared in the laboratory for medical and biotechnological applications. Encapsulated cells are being studied for the treatment of diabetes, liver failure, and other conditions. More recently, there have been extensive studies into the use of encapsulated genetically engineered cells for gene therapy. We recently found that daily orally administered artificial cells, each containing a genetically engineered microorganism, can lower the elevated urea level in uremic rats to normal levels. This may solve the final obstacle of the lack of an effective oral urea removal system for the simple and inexpensive oral treatment of uremia. This is important because 85% of the world's uremic population cannot afford standard dialysis. Other areas of artificial cell application include use in hemoperfusion. Red blood cell substitutes based on modified hemoglobin are already in Phase 3 clinical trials in patients. Artificial cells containing enzymes are being developed for clinical trial in hereditary enzyme deficiency disease and other diseases. They are also being investigated for drug delivery and for use in other applications in biotechnology, chemical engineering, and medicine.

Administration, Oral↗
PubMed1987

Conversion of urea or ammonia into essential amino acids (L-leucine, L-valine, and L-isoleucine) using multienzyme systems and NADH-dextran immobilised in artificial cells.

Artificial cells containing leucine dehydrogenase (EC 1.4.1.9), alcohol dehydrogenase (EC 1.1.1.1; or glucose dehydrogenase, EC 1.1.1.47; or lactic dehydrogenase, EC 1.1.1.27; or malic dehydrogenase, EC 1.1.1.37), urease (EC 3.5.1.5) and dextran-NAD+ were prepared. Ammonia or urea could be converted into L-leucine, L-valine and L-isoleucine using artificial cells with four different multienzyme systems.

Amino Acids, Essential↗
PubMed2001

Present status of modified hemoglobin as blood substitutes and oral therapy for end stage renal failure using artificial cells containing genetically engineered cells.

Artificial cell or bioencapsulation has been developed for use in bioartificial organs, drug delivery, blood substitutes, and other areas. Recent rapid advances in modified hemoglobin blood substitutes have resulted in advance stages of Phase III clinical trials. Another area of use is in oral therapy, using artificial cells microencapsulated with genetically engineered cells for use in end stage renal failure and other conditions.

Administration, Oral↗
PubMedDate not supplied

Ferromagnetic artificial cells for artificial circulation.

It is known that deoxygenated blood is paramagnetic. A ferrofluidic actuator for an implantable artificial heart has been studied. The magnetic fluid consists of ferromagnetic magnetite particles (10 nm). If artificial cells encapsulating ferromagnetic particles are mixed in blood, the circulation is maintained by applying a magnetic field to the blood. An array of two poles of ring solenoids with a gap of 10 mm was mounted near the glass tube (7.60 mm inner diameter). The flux density was 0.236 Tesla. Two experiments were conducted using models of artificial cells: 1) the magnetic fluid and 2) the magnetic fluid and an iron cylinder (6.67 mm in diameter and 28.7 mm in length). A flow of 38 to 8 ml/min was obtained against a pressure of 12.5 to 16.3 mmHg in experiment 1, and 80 to 24 ml/min against a pressure of 53 to 240 mmHg in experiment 2. Calculation showed that magnetic fluids could move against a pressure of 100 mmHg if they had a magnetization of 113 kA/m (B = 0.236 Tesla). The magnetic fluid has a magnetization of 35.6 kA/m, whereas the magnetite is 479 kA/m, and that of iron 1398 kA/m. Artificial circulation with ferromagnetic artificial cells could be feasible if artificial cells with a magnetization of 113 kA/m are developed.

Assisted Circulation↗
PubMed1999

Growth kinetics of genetically engineered E. coli DH 5 cells in artificial cell APA membrane microcapsules: preliminary report.

This paper describes the growth kinetics of genetically engineered E. coli DH5 cells inside the APA membrane artificial cells. The APA microcapsule membrane found does not significantly affects the growth of the encapsulated E. coli DH5 cells. The total protein production of the E. coli DH5 cells inside the APA microcapsules were not significantly different from that of the bacterial cells grown in the free bacterial media. The result also show that the log phase APA artificial cells containing genetically engineered E. coli DH5 would be highly effective for the conversion of various external metabolites.

Alginates↗
PubMed2001

Activation of antigen-specific T cells by artificial cell constructs having immobilized multimeric peptide-class I complexes and recombinant B7-Fc proteins.

T cell activation results from the engagement of multiple receptors on T cells by their respective ligands on antigen presenting cells. Studies using artificial cell surface constructs have demonstrated that effective T cell response requires that antigen be presented on a solid surface with dimensions that approximate those of an intact cell. In this report, we describe the cloning and expression of recombinant B7-1-Fc and B7-2-Fc proteins and their incorporation onto 5-microm latex microspheres along with renatured peptide-MHC. These microspheres provide a simple and effective method for the in vitro or in vivo stimulation of antigen-specific T cells under precisely controlled antigen and costimulation conditions.

Animals↗
PubMed2005

Therapeutic applications of polymeric artificial cells.

Polymeric artificial cells have the potential to be used for a wide variety of therapeutic applications, such as the encapsulation of transplanted islet cells to treat diabetic patients. Recent advances in biotechnology, molecular biology, nanotechnology and polymer chemistry are now opening up further exciting possibilities in this field. However, it is also recognized that there are several key obstacles to overcome in bringing such approaches into routine clinical use. This review describes the historical development and principles behind polymeric artificial cells, the present state of the art in their therapeutic application, and the promises and challenges for the future.

Animals↗
PubMed1992

Artificial cells in immobilization biotechnology.

Artificial cells contain biologically active materials. Artificial cells containing adsorbents have been a routine form of treatment in hemoperfusion for patients. This includes acute poisoning, high blood aluminum and iron, and supplement to dialysis in kidney failure. Artificial cells are being tested for use as red blood cell substitutes. Artificial cells encapsulated cell culture are being tested in animals for the treatment of diabetes and liver failure. A novel 2 step method has prevented xenograft rejection. Artificial cells containing enzymes are being studied for treatment in hereditary enzyme deficiency diseases and other diseases. Recent demonstration of extensive enterorecirculation of amino acids in the intestine has allowed its oral administration to deplete specific amino acids. Artificial cells containing complex enzyme system convert wastes like urea and ammonia into essential amino acids. Artificial cell is being used for the production of monoclonal antibodies, interferons and other biotechnological products. It is also being investigated for drug delivery, and for use in other applications in biotechnology, chemical engineering and medicine.

Biocompatible Materials↗
PubMed2005

Artificial Cell Therapy: New Strategies for the Therapeutic Delivery of Live Bacteria.

There has been rapid growth in research regarding the use of live bacterial cells for therapeutic purposes. The recognition that these cells can be genetically engineered to synthesize products that have therapeutic potential has generated considerable interest and excitement among clinicians and health professionals. It is expected that a wide range of disease modifying substrates such as enzymes, hormones, antibodies, vaccines, and other genetic products will be used successfully and will impact upon health care substantially. However, a major limitation in the use of these bacterial cells is the complexity of delivering them to the correct target tissues. Oral delivery of live cells, lyophilized cells, and immobilized cells has been attempted but with limited success. Primarily, this is because bacterial cells are incapable of surviving passage through the gastrointestinal tract. In many occasions, when given orally, these cells have been found to provoke immunogenic responses that are undesirable. Recent studies show that these problems can be overcome by delivering live bacterial cells, such as genetically engineered cells, using artificial cell microcapsules. This review summarizes recent advances in the therapeutic use of live bacterial cells for therapy, discusses the principles of using artificial cells for the oral delivery of bacterial cells, outlines methods for preparing suitable artificial cells for this purpose, addresses potentials and limitations for their application in therapy, and provides insight for the future direction of this emergent and highly prospective technology.

Journal Article↗
PubMed1992

Artificial cells: 35 years.

The first artificial cells were prepared 35 years ago. They contain biologically active materials. They are now being used in medicine and biotechnology. Artificial cells containing adsorbents are already a routine form of treatment in hemoperfusion. This includes treatment for acute poisoning, high blood aluminum and iron, kidney failure, some types of acute liver failure, and other conditions. Artificial cells are being tested for use as red blood cell substitutes. Artificial cells containing cell culture are being tested in animals for the treatment of diabetes, liver failure, and others. Artificial cells containing enzymes are being tested for treatment in hereditary enzyme deficiency diseases and other diseases. Artificial cells containing complex enzyme system can convert wastes like urea and ammonia into useful amino acids. In biotechnology, artificial cells are being used for the production of monoclonal antibodies, interferons, and other biotechnological products. They are also being investigated for use in other applications in biotechnology, chemical engineering, and medicine.

Animals↗
PubMed1988

Artificial cells as bioreactive biomaterials.

Artificial cells can have the same dimensions as biological cells. They can enclose and retain a large variety of bioreactants. Artificial cell membranes can have the required permeability characteristics to allow the rapid equilibration of external molecules to be acted on by the enclosed bioreactants. Polymer, protein, protein-lipid, polymer-lipid, lipid or other materials can form artificial cell membranes. It is possible to vary the membrane thickness and permeability characteristics over a wide range. Many different forms of bioreactive artificial cells are available. This article contains only a few examples. This includes its applications in (1) red blood cell substitutes; (2) immobilisation of enzymes, multienzymes with cofactor recycling, cell cultures and other biotechnological applications; (3) hemoperfusion in kidney failure, poisoning, removal of aluminum and iron; (4) use in liver failure; (5) other applications in microencapsulation.

Adsorption↗
PubMed1998

Pharmaceutical and therapeutic applications of artificial cells including microencapsulation.

Artificial cells for pharmaceutical and therapeutic applications started as microencapsulation on the micron scale. This has now expanded up to the higher range of macrocapsules and down to the nanometer range of nanocapsules and even to the macromolecular range of cross-linked hemoglobin as blood substitutes. This author first reported microencapsulation of biologically active material in 1957 (T.M.S. Chang, Hemoglobin corpuscles. Research Report for Honours Physiology, Medical Library, McGill University, 1957. (Also reprinted as part of 30th anniversary in Artificial Red Blood Cells Research, J. Biomater. Artif. Cells Artif. Organs 16 (1988) 1-9.) and 1964 (T.M.S. Chang, Semipermeable microcapsules, Science 146 (1964) 524-525). While pharmaceutical research has made use of these approaches for drug delivery, this author has been concentrating on the encapsulation of biotechnological products for therapeutic applications. Therefore, there was little interaction between the two approaches. In the last 10 years, pharmaceutical research, as in other areas of research, has become increasingly interested in biotechnology. Because of this interest, this article is a brief overview of developments of artificial cells for biotechnological products with emphasis on hemoglobin, enzymes, cells and genetically engineered microorganisms.

Animals↗
PubMed2000

Artificial cell biotechnology for medical applications.

Artificial cells are prepared in the laboratory for medical and biotechnological applications. The earliest routine clinical use of artificial cells is in the form of coated activated charcoal for hemoperfusion. Implantation of encapsulated cells are being studied for the treatment of diabetes, liver failure and the use of encapsulated genetically engineered cells for gene therapy. We recently found that daily orally administered artificial cells containing a genetically engineered microorganism can lower the elevated urea level in uremic rats to normal levels and increase the survival of the animal. Furthermore, this can remove potassium, phosphate, uric acid and other waste metabolites from uremic plasma. Blood substitutes based on modified hemoglobin are already in phase-III clinical trials in patients with as much as 20 units infused into each patient during trauma surgery. Artificial cells containing enzymes are being developed for clinical trials in hereditary enzyme deficiency diseases and other diseases. Artificial cells are also being investigated for drug delivery and other uses in biotechnology, chemical engineering and medicine.

Animals↗
PubMed2005

Artificial antigen-presenting cells: artificial solutions for real diseases.

Adoptive immunotherapy, which involves the transfer of autologous antigen-specific T cells generated ex vivo, is a promising strategy to treat a variety of life-threatening diseases. Unfortunately, current approaches for generating sufficient numbers of antigen-specific T cells lack the ability to serve as reproducible and economically viable methods. This has spurred the development of both cell- and non-cell-based artificial antigen-presenting cells to alleviate problems associated with peptide-loaded dendritic cells in current approaches to adoptive immunotherapy. Here, we review new strategies for the ex vivo generation of antigen-specific T cells and their clinical application. These new approaches have the potential to spearhead a new era of successful adoptive immunotherapy for cancer and infectious diseases.

Animals↗
PubMed2004

Artificial cells for cell and organ replacements.

The artificial cell is a Canadian invention (Chang, Science, 1964). This principle is being actively investigated for use in cell and organ replacements. The earliest routine clinical use of artificial cells is in the form of coated activated charcoal for hemoperfusion for use in the removal of drugs, and toxins and waste in uremia and liver failure. Encapsulated cells are being studied for the treatment of diabetes, liver failure, and kidney failure, and the use of encapsulated genetically-engineered cells is being investigated for gene therapy. Blood substitutes based on modified hemoglobin are already in Phase III clinical trials in patients, with as much as 20 units being infused into each patient during trauma surgery. Artificial cells containing enzymes are being developed for clinical trial in hereditary enzyme deficiency diseases and other diseases. The artificial cell is also being investigated for drug delivery and for other uses in biotechnology, chemical engineering, and medicine.

Artificial Organs↗
PubMed1995

Artificial cells with emphasis on bioencapsulation in biotechnology.

The most common use of artificial cells is for bioencapsulation of biologically active materials. Each artificial cell can contain combinations of materials. The permeability, composition and shape of an artificial cell membrane can be varied using different types of synthetic or biological materials. These possible variations in contents and membranes allow for large variations in the properties and functions of artificial cells. Artificial cells containing adsorbents have been a routine form of treatment in hemoperfusion for patients. This includes acute poisoning, high blood aluminum and iron, and supplement to dialysis in kidney failure. Artificial red blood cell substitutes based on modified hemoglobin are already in Phase I and Phase II clinical trials in patients. Artificial cell encapsulated cell cultures are being studied for the treatment of diabetes, liver failure, gene therapy and other conditions. Research on artificial cells containing enzymes includes their use for treatment in hereditary enzyme deficiency diseases and other diseases. Recent demonstration of extensive enterorecirculation of amino acids in the intestine has allowed oral administration to deplete specific amino acids. One example is phenylketonuria, an inborn error or metabolism resulting in high systemic phenylalanine levels. Preliminary clinical studies in patients using bioencapsulation of cells or enzymes have started. Artificial cells containing complex enzyme systems convert wastes like urea and ammonia into essential amino acids. Artificial cells are being used for the production of monoclonal antibodies, interferon and other biotechnological products. Other areas of biotechnological uses include drug delivery, and other areas of biotechnology, chemical engineering and medicine.

Aluminum↗
PubMed1984

Artificial cells in medicine and biotechnology.

Since the feasibility of artificial cells was first demonstrated in 1957 [Chang (1, 2)], an increasing number of approaches to their preparation and use have become available. Thus artificial cell membranes can now be formed using a variety of synthetic or biological materials to produce desired variations in their permeability, surface properties, and blood compatibility. Almost any material can be included within artificial cells. These include enzyme systems, cell extracts, biological cells, magnetic materials, isotopes, antigens, antibodies, vaccines, hormones, adsorbents, and others. Since cells are the fundamental units of living organisms, it is not surprising that artificial cells can have a number of possible applications. This is especially so since artificial cells can be "tailor-made" to have very specialized functions. A number of potential applications suggested earlier have now reached a developmental stage appropriate for clinical trial or application. These clinical applications include the use of such cells as a red blood cell substitute, in hemoperfusion, in an artificial kidney or artificial liver, as detoxifiers, in an artificial pancreas, and so on. Artificial red blood cells based on lipid-coated fluorocarbon or crosslinked hemoglobin are being investigated in a number of centers. The principle of the artificial cells is also being used in biotechnology to immobilize enzymes and cells. Developments in biotechnology have also resulted in the use of the principle underlying the artificial cell to help produce interferons and monoclonal antibodies; to create immunosorbents; to develop an artificial pancreas; and to bring enzyme technology usefully into biotechnology and biomedical applications. Artificial cells are also being used as drug delivery systems based on slow release, on magnetic target delivery, on biodegradability, on liposomes, or other approaches. The present status and recent advances will be emphasized in this paper.

Animals↗