ARTIFICIAL CELLS Jayanti Tokas 1, Rubina Begum 1, Shalini Jain 2 and Hariom Yadav 2 1 Department of...
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Transcript of ARTIFICIAL CELLS Jayanti Tokas 1, Rubina Begum 1, Shalini Jain 2 and Hariom Yadav 2 1 Department of...
ARTIFICIAL CELLS
Jayanti Tokas1, Rubina Begum1, Shalini Jain2 and Hariom Yadav2
1Department of Biotechnology, JMIT, Radaur
2 NIDDK, National Institute of Health, Bethesda,MD20892, USA
Email: [email protected]
Life is endowed with a mysterious and divine
life-force
Artificial Cells
Artificial microscopic structures Same size as biological cells Have some of the functional properties
of biological cells. They contain biologically active
materials.
Properties of an ideal minimal cell
An information carrying polymer Transport across the membrane An external source of chemical energy A catalytic activity Growth and Division Regulation
Hypothetical cell like structure
Membranes
Lipid bilayer vesicles(liposomes)-
Multilamellar vesicles(MLVs)
* Small unilamellar vesicles(SUVs)-5nm-100nm.* Large unilamellar vesicles(LUVs)-100nm-1µm.
Smallest biological cell - 0.2-0.5 µm
Transport across cell membranes
An assisted mechanism is necessary• Carrier molecules• Channels • Pumps
Channels
Neutral peptides Cyclic peptides α-hemolysin A tetrameric channel - M2 protein
Energy Supply
ATP molecules from the environment
Mimic the energy transduction process used by all living cells
Encapsulating Macromolecules
Catalytic activity of the macromolecule is not damaged
Dehydration- re hydration method
Freeze- thaw technique
Injection of molecules
Micro encapsulation
• To separate functional macromolecules • Regulate exchange of materials• Support metabolism• Transduce environmental energy into chemical energy• Synthesize a desired biosynthetic product
Challenges for cell encapsulation
OptimizeBiocompatibility
Mass transfer
Stability
Reproducibility
StructuralFunctional relationship
Increases Long term stability
Repoducible results
A number of commercial machines are
available for automatic production
of artificial cells
Preparation of Artificial cell
Two step Method
Contd..
Contd...
Artificial cellsLike biological cells, Artificial Cells function with content retained inside to – Act on outside permanent molecules Release products of interaction
Macro dimensions For genetically engineered cells, stem cells, other cells, tissues,
microorganisms, etc.
Micron dimensionsFor enzymes, genetically engineered microorganisms and other
microorganisms, peptides, etc.
Nano dimensionsFor blood substitutes, enzymes, peptides, magnetic materials,
drugs, etc.
Molecular dimensionsFor blood substitutes, crosslinked enzymes, conjugated proteins,
etc.
Dimensions of Polymeric Artificial Cells
Artificial cells containing biological cells
Microencapsulated islets for Diabetes Mellitus
Microencapsulated hepatocytes for liver failure
* Stem cells
Artificial cells containing genetically engineered cells
Beta-endorphin secreting cells
Recombinant ciliary neurotrophic factor secreting cells
Oral therapy for Uremia- E.coli DH 5 cells
Artificial cells containing enzymes
Treatment of enzyme deficiency diseases
* Phenylketonuria * Lesch Nyan Disease * Skin Cancer Melanoma
Urea removal
Artificial cells containing microorganisms
Microencapsulation of cholesterol removing microorganisms-
Pseudomonas pictorum
Artificial Cells With Nano-Dimensions
Typical nano-dimension artificial cells
of 80nm mean diameter
Artificial RBC(Hb +Enz) with all
Biochemical properties
Artificial cells in Molecular
Dimensions
•As Oxygen Carrier
Contd..
Aid in Cancer Therapy
Polymeric Artificial cells Containing
CellsCell Content Aim
Cells and Tissues
Pancreatic cells Feedback controlled secretion of insulin for diabetes mellitus
Hepatocytes To support liver function in liver failure
Kidney cells To secrete erythropoietin to treat anemia
Parathyroid Cells To secrete parathyroid hormone to treat hypoparathyroidism
Contd..
Genetically engineered cells
Mouse myoblast (mGH gene) SK2 hybridoma cells
• Secrete mGH for dwarfism• Secrete anti-hIL-6 monoclonal Abs for IgG1 plasmacytosis
Mouse myoblasts (human factor IX geen)
Secrete human factor IX for hemophilia B
Hamster kidney cells (CNTF gene) Secrete ciliary neutrotrophic factor for amytrophic lateral sclerosis
Neuro2A cells (pro-piomelaocortin gene)
Secrete β-endorphin for pain treatment
Stem cellsStem cells plus hepatocytes Increase duration of viability and
function of hepatocytes
Contd..
Microorganisms
Pseudomonas pictorum
To remove
Erwinia herbicola To convert ammonia pyruvate and phenol into lysine and DOPA
CDH5 E.coli Urea removal
Metabolic induction of Lactobacilus delbruecki
Urea removal
Bioactive sorbants
Activated charcoal and resins Ultra thin coating of colloidal membrane Detoxify the blood – hemoperfusion.
McGill Artificial Cells and Organ Research Centre in the late 1960s.
Hemoperfusion
Patient’s blood
Charcoal-filled artificial cells
Toxins in the blood to enter the cells
Adsorbed by the charcoal.
Artificial cells as drug delivery vehicles
Drug (biodegradable membrane)
fusion
Target tissue membrane degraded
Drug released
Artificial cells as biosensors
Artificial cells
analytes
signal
Coenzyme-depleted enzyme - glucose oxidase
Artificial Cell Membrane Holds Promise For Medical Use
• Detecting Flue Virus
• Anti-inflammatory Agent
Tailored Glycolipids(sialic acid)
Specific Protein
(Coat proteins of Influenza virus)
Pink film
Bind
Infection/Injury
Blood Vessels ProduceReceptors
WBC/Neutrophils Bind
Inflammatory Agents
Excess
* Rheumatoid Arthritis
* Septic Shock
* Clamping of Blood Vessels
During Surgery
Contd..
Polymerized Membrane
Prevents attachment to
Blood Vessels
Sugars
Artificial red blood cells
Modified hemoglobin
* high oxygen carrying capacity
* do not have blood group antigens
* longer half life
* non toxic
Extracting Hb from RBC’s
RBC’s contain Hb which transport O2 through body
RBC’s are lysed with E-Pure water to extract Hb
E-Pure Water
Modified Hemoglobin
I generation II generation III generation
Why Cross-link Hb?
+ Cross-linker
In body
Hemoglobin must be cross-linked when placed in the blood stream.– Hb breaks into dimers which can travel through
capillary pores (holes) and cause death.
Hb dimers are small enough to travel through pores
Cross-linked Hb can no longer travel through pores
Present status Hemoperfusion for acute poisoning (clinical
trials) Hemoperfusion for aluminium and iron overload
(clinical trials) Red blood cell substitute (clinical trials) Diabetes mellitus animal experiments (clinical
trials) Drug delivery systems Artificial liver support (experimental) Hereditary enzyme deficiency (clinical trials)
NASA supported Researches for dehydrated blood Supplies
Artificial Sperm
Artificial Human Eggs Possible In 5 years
Artificial Human Egg
• Haploidisation
• No Cloning
• Production of Reconstituted Egg
Procedure
Woman’s Somatic Cell
Shelled Out Oocyte
*Remove Nucleus
*Transfer
* Problem
Artificial Sperm
* Dr. Orly Lacham Kalpan succeeded in fertilizing a normal egg with an artificial
sperm.
* Embryo Developed normally in Lab
Conclusion
• Artificial cells allow to combine properties of biological systems for therapeutic and diagnostic applications.
•Artificial cell is an attempt to mimic some of the biological processes of a real cell, it may ultimately prove most useful as a partial substitute for animal cells.