Nanotechnology in Transfusion medicine

Nanotechnology Technology development at the atomic,

molecular, or macromolecular range of approximately 1-100 nanometers that is able to create structures, devices, and systems that have novel properties.

1 nanometer = 1 x 10-9 m

A nanometer is a billionth of a meter.

The emerging field of nanotechnology involves scientists from many different disciplines, including physicists, chemists, engineers, and biologists.

There are many interesting nanodevices being developed that have a potential to improve cancer detection, diagnosis, and treatment.

Applications of Nanotechnology

in Medicine and Health

Diagnostics Using Sensors and Micro Electro Mechanical Systems (MEMS) & implants

Drug Delivery Using Nanoparticles and

Molecular Carriers

Lab on a Chip and Advanced Drug

Delivery Systems

As diagnostics

Biosensing

Microarrays: genes and proteins

Nanoparticle complexes of DNA and peptides

Designing Nanodevices forUse in the Body

Nanostructures can be so small that the body may clear them too rapidly for them to be effective in detection or imaging.

Larger nanoparticles may accumulate in vital organs, creating a toxicity problem.

Scientists will need to consider these factors as they

attempt to create nanodevices the body will accept.

Designing Nanodevices forUse in the Body

Nanodevices AreSmall Enough to Enter Cells

Most animal cells are 10,000 to 20,000 nanometers in diameter.

This means that nanoscale devices(less than 100 nanometers) can enter cells and the organelles inside them to interact with DNA and proteins.

Tools developed through nanotechnology may be able to detect disease in a very small amount of cells or tissue.

They may also be able to enter and monitor cells within a living body.

Nanodevices CanPreserve Patient’sSamples Many nanotechnology tools will make it possible for

clinicians to run tests without physically altering the cells or tissue they take from a patient.

This is important because the samples clinicians use to screen for cancer are often in limited supply.

It is also important because it can capture and preserve cells in their active state.

Scientists would like to perform tests without altering cells, so the cells can be used again if further tests are needed.

Uses for nanotechnology in health There are several developments in nanotechnology

that can help improve health in developing countries.

Disease diagnosis and screening Nanolitre systems (known as lab-on-a-chip): devices

that automate a biological process using fluids at the nanolitre scale.

Quantum dots: Nanosized semiconductors that can be used as biosensors to find disease. Because they fluoresce they can be used to tag diseased cells.

Magnetic nanoparticles: used as nanosensors

Nanosensor arrays: grids of carbon nanotubes

Antibody-dendrimer conjugates: branched nanomolecules with antibodies on their ends for diagnosis of HIV and cancer

Carbon nanotubes and flatter, thin wires called nanobelts or nanowires (often made of gold) as nanosensors for disease diagnosis as they bond to biomarkers that indicate cancer such as mutated RNA

Nanoparticles as medical image enhancers: Medical imaging relies on looking for contrasts in the way light is scattered in healthy tissue compared with diseased tissue.

The sharper this contrast, the more accurate the diagnosis.

Nanoparticles are able to give medical imaging techniques a sharper resolution, making it easier to identify disease.

Drug delivery systems

The choice of system depends on the way they bind with the drug and the type of drug treatment.

Nanocapsules: These are pods that encapsulate drugs, which ensures the drugs are released more slowly and steadily in the body

Liposomes: Artificial vesicles made up of a lipid bilayer so they can fuse with and penetrate membranes easily. These have been used to treat diseases such cancer, fungal infections, hepatitis A, and influenza

Dendrimers: tree-shaped synthetic nanomolecules that carry drugs in the tips of the branches.

Buckyballs: spherical nanoparticles can carry more than one drug at a time.

They are useful in the treatment of diseases such as cancer and other diseases where monotherapy can lead to drug resistance

Nanobiomagnets which carry drugs, for cancer for instance, into the body and are held at the target site by an external magnet.

The purpose of this is to concentrate the drug at the tumour site for long enough for it to be absorbed.

Nanotechnology can also provide alternatives to injectable vaccines if the inactive virus is bound up with nanoparticles to increase the immune response.

Nanotechnology and Cryo preservation “[Nanotechnology] will revolutionize the

process of ensuring the compatibility of blood products and the reduction of the risk of infectious disease transmission …”

Research in cyrobiology focuses on understanding how freezing affects the viability of cells.

Storage of frozen blood products is critically important to the maintenance of an inventory of rare blood types and also to the storage of hematopoietic stem cells for transplantation.

Canadian Blood Services scientists have unravelled some of the mysteries surrounding the freezing process and have developed new strategies to minimize the damage to cells caused by this freezing process.

They have developed new freezing processes and identified unique protectant solutions that will improve the recovery of live cells after the thawing process.

In collaboration with the University of Alberta, Canadian Blood Services researchers are investigating the opportunity presented by nanotechnology to analyse samples from blood donors in a new way.

The miniaturization of blood donor testing of all types onto a single chip will revolutionize the process of ensuring the compatibility of blood products and the reduction of the risk of infectious disease transmission.

The efficiency of the blood system will be improved by immediate testing prior to donation rather than the present system of testing post-donation.

Nanotechnology will permit the rapid genetic analysis of a blood donation for the full range of blood group antigens rather than simply the ABO and Rh groups that are typed at present.

This information will make the process of cross-matching blood for transfusion purposes more complete and safer for patients.

Health monitoring Nanotubes and nanoparticles can be used as glucose,

carbon dioxide and cholesterol sensors and for in-situ monitoring of homeostasis, the process by which the body maintains metabolic equilibrium.

In developing nations, the use of nanotechnology is also being explored in the fight against infectious diseases such as HIV and TB.

Nanotechnology in cancer Nanotechnology advances have been heavily focused

on cancer, mainly on diagnosis and drug delivery.

Drugs carried by polymer-coated nanoparticles have been used to treat multidrug-resistant breast and ovarian cancer with the chemotherapies

Tuberculosis and nanotechnology

The Central Scientific Instruments Organisation of India has designed a nanotechnology-based TB diagnostic kit, currently undergoing clinical trials.

This would cut both the cost and time required for TB tests, and also require a smaller amount of blood for testing.

Artificial cells The general principles of artificial cells can form the

basis of a large number of artificial systems

In addition to being of cellular dimensions in the micron range, they can also be in the macro range, nano range or molecular range

The membrane material includes polymer, biodegradable polymer, lipid, crosslinked protein, lipid-polymer complex, lipid-protein complex and membrane with transport carriers.

Nanobiotechnology is the assembling of biological molecules into nanodimension structures, membranes with nanodimension thickness or nanotubules with nanodimension diameter.

An example of assembling of biological molecules to formpolyHb and conjugated Hb

Examples of different types ofnanobiotechnology-based polyHb-enzymes

There are three steps in the development of a complete artificial RBC i.e. developing:

1) A micron dimension artificial red cell

2) A submicron lipid membrane artificial red blood cell

3) A nanodimension biodegradable membrane artificial RBC.

Micron Dimension Artificial RBCs with Ultrathin Polymeric Membrane

The first attempt at preparing an artificial red blood cell involved replacing the red blood cell membrane with an ultrathin polymeric membrane

Submicron Lipid Membrane Artificial RBCs

Preparation larger lipid membrane artificial cells where the lipid is supported in the form of lipid-protein membrane and lipid polymer membrane

In 1980 Djordjevich and Miller submicron 0.2 micron diameter artificial RBC’s using lipid membrane vesicles to encapsulate hemoglobin

This increased the circulation time significantly, although it was still rather short.

The most successful approach to improve the circulation time is to incorporate polyethylene-glycol (PEG) into the lipid membrane artificial RBC’s resulting in a circulation halftime of more than 30 h

Nanodimension Biodegradable Polymeric Membrane RBCs

Aim To prepare nanodimension artificial

RBC’s with the following properties:

1. Contains little or no lipid in the membrane.

2. Persist in the circulation after infusion for a sufficiently long time.

3. Be stable in storage.

4.Remains stable after infusion for the duration of its function as a blood substitute — but it has to be biodegraded soon after the completion of its action in the body.

5. The membrane material and its degradation products have to be nontoxic.

6. In addition to hemoglobin, the nano artificial cells should contain important RBC enzymes like superoxide dismutase, catalase, carbonic anhydrase and methemoglobin reductase

7. The membrane should be permeable to reducing agents and/or glucose.

With the availability of methods to prepare artificial cells of nanometer dimensions started to prepare hemoglobin nanocapsules of less than 0.2 micron mean diameter using polylactic acid (PLA) membrane, PEG-PLA membrane and other biodegradable polymers

Characterization of Nano Artificial RBCs Electromicroscopic appearance

membrane thicknessis 5–15 nm.

Size distribution of polylactide membrane artificial rbc’s The diameter and size distribution of the biodegradable

hemoglobin are determined by using the Nicomp Size Analyzer (Model 370).

The instrument operates by light scattering.

The mean diameters of the biodegradable hemoglobin nanocapsules can be shown to be as low as 74 nanometers.

Other properties

Safety and Efficacy of Nano Artificial RBCs

Amount and fate of PLA membrane

The membrane material of Poly Lactic Acid nano artificial RBC’s is made up mostly of biodegradable polymer with a minimal amount of lipid.

Since polymer is stronger than lipid and is also porous, much less membrane material is required.

Polylactic acid is degraded in the body into lactic acid and then to carbon dioxide. These are all normal body metabolites.

Efficiency in nanoencapsulating hemoglobin

At present, the hemoglobin nanoencapsulation efficiencies range from 13 to 29% of the starting quantities of hemoglobin, depending on the polymer used

Nano artificial RBC’s prepared with poly(D.L.)lactic acid contained fewer defects in the membrane than that prepared using poly(L)lactic acid

Circulation Time of Nano Artificial RBCs Circulation half-life of PLA nano artificial

RBC’s is evaluated in anesthetized male rats.

Each rat received 1/3 of its blood volume via

intravenous top loading.

PLA artificial red blood cell is removed very rapidly from the circulation.

Immunohematology The QWALYS® 3 is a new generation of fully-

automated and high-throughput systems for immunohematology; grouping, phenotyping, donor antibody screening, antibody screening, identification and cross-matching can all be easily performed.

The QWALYS® 3 is the only system using E.M.® Technology, an innovative nanotechnology based on the magnetization of red blood cells.

Higher throughput- Up to 105 Grouping or 110 Antibody Screening or 250 Antibody Screening donors per hour.

HIV Nanotechnology-based techniques are being

widely evaluated in medical testing and could provide a new generation of diagnostic assays due to their high degrees of sensitivity, high specificity, multiplexing capabilities, and ability to operate without enzymes

A nanoparticle-based biobarcode amplification (BCA) assay for early and sensitive detection of HIV-1 capsid (p24) antigen by using antip24 antibody-coated microplates to capture viral antigen (p24) and streptavidin-coated nanoparticle-based biobarcode DNAs for signal amplification, followed by detection using a chip-based scanometric method

Respirocyte The artificial red blood cell or "respirocyte“

Proposed here is a blood borne spherical 1-micron diamondoid 1000-atm pressure vessel with active pumping powered by endogenous serum glucose, able to deliver 236 times more oxygen to the tissues per unit volume than natural red cells and to manage carbonic acidity

Artificial platelets (Clottocyte) An artificial mechanical platelet appears to halt

bleeding 100-1000 times faster than natural hemostasis.

A single clottocyte, upon reliably detecting a

blood vessel break, can rapidly communicate

this fact to its neighbors, immediately

triggering a progressive controlled mesh-

release cascade.

Artificial Platelet

vasculoid The vasculoid is a single, complex,

multisegmented nanotechnological medical robotic system capable of duplicating all essential thermal and biochemical transport functions of the blood, including circulation of respiratory gases, glucose, hormones, cytokines, waste products, and cellular components.

This nanorobotic system, a very aggressive and physiologically intrusive macroscale nanomedical device comprised of ~500 trillion stored or active individual nanorobots, weighs ~2 kg and consumes from 30-200 watts of power in the basic human model, depending on activity level.

The vasculoid system conforms to the shape of existing blood vessels and serves as a complete replacement for natural blood.

References Internet Regenerative Medicine, Artificial Cells

and Nanomedicine – Thomas Ming Swi Chang McGill University, Canada

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