Artificial Blood Made with Nanoparticles by University of North Carolina Chemists Using Soft Imprint Lithography Techniques

 Nanoparticle Derived Artificial Red Blood Cells

Manufacturing techniques used to produce semiconductors have now been used to make artificial red blood cells.  University of North Carolina (Chapel Hill, NC) Professors of Chemistry Joseph M. DeSimone and Edward T Samulski have developed a lithographic fabrication technique to produce nanoparticles that are used to create artificial blood capable of transporting oxygen as well as therapeutic and diagnostic agents, according to U.S. Patent Application 20100028994.

An artificial red blood cell is made of particles that are substantially monodisperse and each particle has a common largest linear dimension of between about 5 microns to about 10 microns and a modulus less than about 1 MPa such that each particle can pass through a tube having an inner diameter of less than about 3  microns. The artificial red blood cell particles are made of hydrophilic poly(ethylene glycol) or perfluoropolyether.

The artificial red blood cell particles further have a surface functionality selected from the group consisting of PEGylation, blood type antigens, and natural mimics. The artificial red blood cell particles can carry  a cargo selected from the group consisting of a therapeutic agent, hemoglobin, or an imaging agent. The artificial red blood cell cargo is capable of binding and releasing oxygen.

The artifical blood particles may carry a wide variety of cargos. Particles may incorporate therapeutics, such as small molecules, proteins, oligos, siRNAs, and pDNA, imaging beacons for PET, SPECT, MR, and ultrasound, as well as organelles. In some embodiments, no chemical modification of the cargo is needed. High roadability is also possible.

Materials can be incorporated into the artificial blood particle composition to treat or diagnose diseases including: Allergies; Anemia; Anxiety Disorders; Autoimmune Diseases; Back and Neck Injuries; Birth Defects; Blood Disorders; Bone Diseases; Cancers; Circulation Diseases; Dental Conditions; Depressive Disorders; Digestion and Nutrition Disorders; Dissociative Disorders; Ear Conditions; Eating Disorders; Eye Conditions; Foodborne Illnesses; Gastrointestinal Diseases; Genetic Disorders; Heart Diseases; Heat and Sun Related Conditions; Hormonal Disorders; Impulse Control Disorders; Infectious Diseases; Insect Bites and Stings; Institutes; Kidney Diseases; Leukodystrophies; Liver Diseases; Mental Health Disorders; Metabolic Diseases; Mood Disorders; Neurological Disorders; Organizations; Personality Disorders; Phobias; Pregnancy Complications; Prion Diseases; Prostate Diseases; Registries; Respiratory Diseases; Sexual Disorders; Sexually Transmitted Diseases; Skin Conditions; Sleep Disorders; Speech-Language Disorders; Sports Injuries; Thyroid Diseases; Tropical Diseases; Vestibular Disorders; Waterborne Illnesses and others.

Method of Making Monodisperse Nanostructures with a Variety of Shapes and Sizes for Use in Artificial Red Blood Cells

Artificial blood compositions are made with  a novel "top down" soft lithographic technique; non-wetting imprint lithography (NOWIL) which allows completely isolated nanostructures to be generated by taking advantage of the inherent low surface energy and swelling resistance of cured PFPE-based materials.

Without being bound to any one particular theory,  DiSimone and Samulski say,  a key aspect of NOWIL is that both the elastomeric mold and the surface underneath the drop of monomer or resin are non-wetting to this droplet. If the droplet wets this surface, a thin scum layer will inevitably be present even if high pressures are exerted upon the mold.

When both the elastomeric mold and the surface are non-wetting (i.e. a PFPE mold and fluorinated surface) the liquid is confined only to the features of the mold and the scum layer is eliminated as a seal forms between the elastomeric mold and the surface under a slight pressure. The manufacturing methods provides for the first time a simple, general, soft lithographic method to produce nanoparticles of nearly any material, size, and shape that are limited only by the original master used to generate the mold.

Using NOWIL, nanoparticles composed of 3 different polymers were generated from a variety of engineered silicon masters. Representative patterns include, but are not limited to, 3-.mu.m arrows, conical shapes that are 500 nm at the base and converge to <50 nm at the tip, and 200-nm trapezoidal structures. Definitive proof that all particles were indeed "scum-free" was demonstrated by the ability to mechanically harvest these particles by simply pushing a doctor's blade across the surface.  

Mammalian red blood cells are critical for the delivery of oxygen to body tissues and the exchange of carbon dioxide from body tissues. One critical feature of red blood cells (RBC) is their ability to severely deform in shape to pass through intercellular gaps of sinusoids in the spleen and capillaries. The artificial blood cells have this same ability. 

DeSimone Research Synopsis

The recent breakthroughs in the DeSimone laboratories using specifically-designed materials for imprint lithography have enabled an extremely versatile and flexible method for the direct fabrication and harvesting of monodisperse, shape-specific nano-biomaterials. The method, referred to as Particle Replication In Non-wetting Templates, or PRINT, allows for the fabrication of monodisperse particles with simultaneous control over structure (i.e. shape, size, composition) and function (i.e. cargo, surface structure).

Unlike other particle fabrication techniques, PRINT is delicate and general enough to be compatible with a variety of important next-generation cancer therapeutic, detection and imaging agents, including various cargos (e.g. DNA, proteins, chemotherapy drugs, biosensor dyes, radio-markers, contrast agents), targeting ligands (e.g. antibodies, cell targeting peptides) and functional matrix materials (e.g. bioabsorbable polymers, stimuli responsive matrices, etc).  PRINT particles are presently being designed to reach new understandings and therapies in cancer prevention, diagnosis and treatment.

 Early detection via targeted delivery of the imaging agent goes hand in hand with these new directions. Cellular targeting can be accomplished by attaching cell-specific ligands to the surface of the PRINT particle. Potential cell-specific ligands include the integrin receptor peptide (GRGDSP), melanocyte stimulating hormone, vasoactive intestional peptide, anti-Her2 mouse antibodies, cell-penetrating peptides, and a variety of vitamins.

Once targeted with a cell specific ligand, the PRINT particle can be delivered and imaged at the desired site. In this respect, PRINT particles promise great potential, since it is possible to utilize the ability to specifically target, be shape and size-specific, possess tunable matrixes, as well as the ability to incorporate imaging contrast agents. The PRINT technology from DeSimone’s lab is playing an integral part in the NIH PPG as well as the newly awarded Carolina Cancer Center of Nanotechnology Excellence Grants.