1 Drug delivery systems
4.1 Wound dressing
5 Green Synthesis of Nanostructures
6 Medical Imaging
7 DNA Nanostructures
7.1 DNA Origami
8 Multimodal Therapy
Cyclodextrins are cyclic oligosaccharide which are make from different numbers of glucopyranose that are conjugated to each other through α-1,4 glycosidic bonds. They are consider as a class of host-guest nano-complex which are used in different shape (rotaxane, pseudorotaxane, nanocapsule, nanosponge, …) for delivery of hydrophobic components such as hydrophobic drugs. The aim of these complexes is enhancement in the solubility and bioavailability of hydrophobic drugs like different types of anticancer drugs.
Figure1. Schematic of different types of supramolecular cyclodextrin nanocarriers.
Superparamagnetic iron oxide nanoparticles are considered as contrast agents for use in magnetic resonance imaging (MRI) which can be good alternatives for toxic gadolinium particles. Coating the surface of these particles with biocompatible polymers not only improve their colloidal stability and biocompatibility, but also provide the ability of drugs/gene loading by the nanocarriers. Based on these excellent properties these nanoparticles can be applied as theranostic agents in the field of nanomedicine.
Figure2. SPION applications: therapy and diagnosis.
Graphene oxide is a class of graphene based nanosheets that is composed of some graphene sheets which are oxidize under certain conditions. The presence of carboxyl groups (as hydrophilic groups) at the corner of the sheets and the hydrophobic surface of the sheets introduced them as a carrier for both hydrophobic and hydrophilic drugs. Moreover, they can be modified with different polymeric shells in order to increase their water solubility, biocompatibility and drug loading capacity.
Figure3. Graphene oxide as drug delivery system.
Biological agents such as some of milk proteins can act as a favorite nanocarrier for hydrophobic drugs. In these cases biological agents can be formed in different shapes like micelles, liposomes and so on due to their three-dimensional structural and molecular features and drugs can be inserted in the hydrophobic part of nanocarrier.
Figure4. Milk proteins can act as nanocarrier for drug delivery.
Responsive polymers or smart polymers are new class of polymers which can be acted as coating agents for nanoparticles or as nanocarrier themselves. The performance of these polymers is based on their capability of responding to very small changes in the environment such as pH, temperature, redox, light and etc.
Figure5. Stimulating factors for responsive polymers.
Carbon nanotubes (CNT) have appeared to be encouraging candidates for anti-cancer drug delivery systems, since they provide potential advantages such as have a higher surface area (1300 m2/gr) allowing for higher drug loading and possibility for accompanying additional therapeutic ligands through surface functionalization. In addition, their inherent stability and architectural flexibility lead to prolonged circulation time; hence improving bioavailability of the drug molecule.
Figure6. CNTs as nanocarriers for drug delivery.
Liposomes can serve as promising carriers for targeting delivery and controlled release of anti-cancer drugs. They have the most similar structure to the cell membrane and are consist of amphiphilic lipid bilayer(s) with hydrophilic head and hydrophobic tail. Drugs can be trapped in the internal polar cavity or within the nonpolar layer.
Figure7. Liposomal drug delivery system
Theranostics is “The fusion of therapeutic and diagnostic technologies” to monitor early response to treatment and predict treatment efficacy. It could optimize efficacy and safety of therapeutic regimes by monitoring the response to treatment as well as performing noninvasive imaging instead of repetitive biopsies with severe trauma. Cancer nanotheranostics is the science and technology of fabricating nano platforms to co-deliver both imaging and therapeutic components to cancer sites. The advantages of Nanotheranostics over conventional Theranostics comes out from the significant properties of materials when turn into nano size such as increasing the payload per surface, precluding from being readily cleared through the kidneys, extending circulation in the blood pool and easily extravasating from the blood pool into tumor tissues and be retained due to poor lymphatic drainage (EPR).
Figure8. Schematic of a theranostic nanoparticle
Cyclodextrin encapsulation ability can be applied for synthesis of different types of biosensors. These nanosystems can be synthesis through combination of cyclodextrin with other nano materials or by using cyclodextrin alone. These new types of biosensor are useful materials for determine the amount of different types of pollutant, drugs, hormones and heavy metal ions.
Figure9. Schematic of a nanocomposite of cyclodextrin and conductive substrate for biosensing applications
Aptamers biosensors are very specific sensors which are consist of single-stranded nucleic acids (DNA or RNA) that are selectively bind to the target molecule. This aptamers technology is a biomedical diagnosis approach that can be used to identify different types of desired molecules at the same time, the advanced technique which is named as lab on a chip.
Figure10. Aptamers biosensor.
Graphene and its derivatives with unique properties like high specific surface, good mechanical flexibility, and high thermal and electrical conductivity is a candidate for synthesis of different types of biosensors. Here they can be act as a substrate for attachment of other component like aptamers, enzymes, ligands, nanoparticles and so on.
Figure11. Schematic of graphene based biosensor.
Covering the wound by bands is a helpful method for its healing. In this context the nanocomposite of polymers and anti-bacterial nanoparticles can be ideal candidate for apply in wound dressing applications. These nanocomposites not only prevent the bacterial contaminations but also by loading different component in the composite can accelerate the healing process.
Figure12. Wound dressing nanocomposite.
Green synthesis is a new and safe method for synthesis of different types of nanoparticles without using of chemical solvents. In this approach nanoparticles are synthesis by reduction of a certain metal salt to its zero charge model in the presence of the extract of plants or animals or through the extraction of the as prepared nanoparticles which are inside the body of bacteria. Among them silver nanoparticles are the most famous nanoparticles which are synthesis by this approach in recent years due to its widely application as anti-microbial agent.
Figure13. Green synthesis of nanoparticles.
Combining different types of diagnostic approach is a useful method for enhancing the detection process since each one has advantages and disadvantages and can cover the defects of each other. In fact, by using multimodal imaging agents in a single nanocarrier and comparing the resulted images, detection of the disease and its recovery process can be improved. As an example, it can be note to the iron oxide – Au core shell nanoparticles which can be used in the combination of CT/MR imaging approach.
Figure14. CT/MR imaging by Fe3O4-Au core-shell nanoparticles.
DNA origami is a subclass of nanobiotechnology which is based on the modeling of long single stranded DNAs into the desired shape through intermolecular junction between complementary base pairs. Biocompatibility, availability and ease of production introduce these nanosystems as an ideal candidate for different applications like drug/gene delivery.
Figure15. Synthesis of different nanostructures with DNA.
Multimodal therapy is the simultaneous use of two or more therapeutic approaches in order to improve their therapeutic effects. In this context it can be noted to the combination of chemotherapy and radiotherapy in which chemotherapeutic approach is used to stop the cell cycle of diseased cells in stage that is sensitive to the radiation and so can enhanced its curative efficacy.
Figure16. Combination of chemotherapy and radiotherapy for cancer cell therapy.