ARTIFICIAL CELLS

Jayanti Tokas1, Rubina Begum1, Shalini Jain2 and Hariom Yadav2

1Department of Biotechnology, JMIT, Radaur2 NIDDK, National Institute of Health, Bethesda,MD20892, USA

Email: yadavhariom@gmail.com

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 Structural

Functional 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 cellsMouse 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 removalMetabolic 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.