Nanomedicine is an area of medical applications that focus on the use of nanotechnology for the diagnostic of diseases, delivery of drugs, and repair of damaged tissues in patients. The materials that are used by this technology are named nanomaterials due to their size which is within the nanometer range.
What Is a Nanomaterial?
Nanomaterials are chemically synthesized or assembled products that have sizes that are within the nanometer ranges, and which include dendrimers, liposomes, metal nanoparticles, nanocrystals, nanosuspensions, polymer nanoparticles, block copolymer micelles, and polymer therapeutics.
1- What is a Dendrimer?
Dendrimers are chemical structures that are generated by a repetitive assembly of molecules leading to the formation of a molecule with a central core, a network of branched molecules, and terminal functional groups at the surface responsible for the spherical form of dendrimers . Dendrimers can be conjugated with drugs and detecting agents for delivery to tissues within the body.
2- What is a Liposome?
Liposomes are chemically engineered spheres that contain at least one phospholipid layer. They are usually obtained by dispersing phospholipids in water which creates vesicles named liposomes. Once loaded with drugs or DNA, liposomes can cross cellular membranes and deliver their load within the cells .
3-What Is a Metal Nanoparticle?
Metal nanoparticles are structures that are made of a metal core that is covered by inorganic or organic materials. Metal elements that are used in the production of metal nanoparticles include gold, aluminum, iron, silica, silver, copper, zinc, manganese, nickel, cerium, and titanium .
4-What Are Nanocrystals?
Nanocrystals are generated by the microionization and size homogenization of crystals into nanomer-sized particles. They are formed by a crystalline core and a stabilizer layer made of agents such as sodium lauryl sulfate, polyvinyl pyrrolidone K30, pluronics F68 and F127, Tween 80, hydrophobin, or hydroxypropyl methylcellulose.
Nanocrystals have been used in drugs delivery to improve the dissolution properties of poorly soluble drug materials .
5- What Are Nanosuspensions?
Nanosuspensions are solid drug nanoparticles that are suspended in an aqueous vehicle to facilitate their water solubility and stability. These solid drugs may have poor aqueous solubility which affects their therapeutic efficacy and increases their toxicity .
6- What Are Polymer Nanoparticles?
Polymer nanoparticles are chemically synthesized molecules through the assembly and bonding of repeated chemical subunits. They are specifically made to overcome challenges associate with a carrier system such as biocompatibility, biodistribution, side-effects, and biological barriers .
7- What Are Block Copolymer Micelles?
Block Copolymer Micelles are self-assembled chemical molecules made of oppositely charged copolymers in an aqueous or organic solution. They are constituted of hydrophytic heads on the outside and hydrophobic tails on the inside. They are used as carriers for drug delivery and gene targeting .
8- What Are Polymer Therapeutics?
Polymer therapeutics are water-soluble polymers that are conjugated to proteins, micelles, or drugs to generate complex drugs such as polymer-protein conjugates, polymer-micelles conjugates, or polymer-drugs conjugates, respectively. Due to their enhanced water solubility of the conjugated and reduced toxicity, polymer therapeutics are used for multi-drug delivery and wound healing applications .
What Are the Applications of Nanomedicine?
1- Nanomedicine Applications in Diagnosis
Due to their capacity for conjugation to dyes, proteins (e.g., ligands), and imaging agents, nanoparticles are used for early and accurate diagnosis and monitoring of patients via direct imaging of the tissue of patients (in vivo) or by running tests on samples from patients (in vitro) .
Imaging of Tissues and Organs of Patients
To enhance the contrast of structures and fluids within the body of patients, nanoparticle-based contrast agents are successfully used for imaging technologies such as MRI (Magnetic Resonance Imaging), PET (Position Emission Tomography) scan, CT (computed tomography), PAT (Photoacoustic tomography), Raman spectroscopic imaging, and multimodal imaging .
Diagnostic Tests Using Nanoparticles
Nanoparticles are used to produce in vitro diagnostic devices or biosensors that are used to detect and potentially measure biological reactions such as antibody binding to an antigen, nucleic acids hybridization, or ligand binding to the surface of cells .
2- Nanomedicine Applications in Therapy
Nanoparticles are mainly used for the delivery of drugs to patients through oral or skin applications, or by injection. For instance, the liposome product Doxil® is used to deliver the chemotherapeutic drug Doxorubicin to tumors and with reduced toxicity for the heart and kidneys .
For the treatment of metastatic breast cancer and non-small-cell lung cancer, the polymer mPEG-PLA is being used for the delivery of the chemotherapeutic drug Paclitaxel . Gold nanoparticles that bind to cancer cells can be used to tag these cells for irradiation by infrared laser leading to their death .
Nanomedicine is a relatively new medical application that already has significant impacts on the diagnosis and drugs delivered to patients. Although it is still a domain of science fiction, some scientists suggest the futuristic possibility of creating nanorobots that can repair or detect damages and infections.
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