Quantum Dots For Drug Delivery Biology Essay

Quantum sexually transmitted diseases For medicine delivery Biology EssayA dose delivery carcass give the axe be defined as the mechanism for the introduction of medicate and different alterative agents into the body for treating any disease. An ideal do medicines delivery schema possesses two elements (1) the ability to target -to ensure high gear aptitude and keep down the side effects, (2) controlled do drugs release (3) prevention of side effects 8. victimisation nanomaterials for drug delivery NDD (nanoparticle drug delivery) has the fol secondarying advantagesreduced drug perniciousnessbetter penetration of the particlesdifferent delivery routesminimizes the irritant reactions repaird bio-availability and change magnitude circulation judgment of convictioncontrolled drug release and targetingIt is one of the Green Technology methods as the focus is on minimizing the hazard side effects and maximizing the efficiency of any chemical (drug) of choice and replac ing the existing products with new nanoparticles that be friendly throughout their lifecycle8,7.QUANTUM DOTS FOR NDDSNDDS means Nanoparticle Drug Delivery System. A system with high sensitivity, large resolution, and low cost is needed for the maintenance of drug delivery i.e. to check the nanocarrier distribution, drug release and degradation inside the body. Quantum Dots atomic number 18 highly suitable for such systems.1 The substantial characteristics of Quantum dots which make them suitable for drug delivery systems argon broken surface, versatility of surface interpersonal chemistry to incorporate conf utilize drugs, queer optical properties for real(a) time monitoring of drug hex and release or so(prenominal) at systemic and cellular levels. These Quantum Dots backside be utilize as carriers by integrating with more drugs and also used as tags for opposite drug carriers. 6WHY QUANTUM DOTSOne of the crucial reasons wherefore Quantum Dots are preferred is that it can be used for the traceable drug delivery as it has the potential to elucidate the pharmacokinetics (what the body does to the drug) and pharmacodynamics (what the drug does to the body) of drug when it is introduced into our body 6. Using QDs result be a combination of unique physical, chemical, and optical properties which helps to study the interactions of these nanocarriers with biological systems through real-time monitoring and calculating the biodistribution of nanoparticle, drug release, intracellular uptake and degradation 5. Comparing to the conventional tomography techniques like MRI and PET, the optical imaging utilise Quantum Dots is highly handsome with high resolution and at very cheap cost which go forth automatically prolong to the reduction of time involved in the phylogeny of new drug and more discoveries in the field 6.ADVANTAGES OF USING QDs optic imaging with high resolution, high sensitivity, multiplexing, and low costSmall size which leads to le ss amount of drug usage and low drug perniciousnessVersatile surface chemistry,Improved bioavailability and delivery of drug in a controlled and sustained mannerDecreased incidence of side effects and improve patient complianceComparing another(prenominal) conventional probes, QDs are more(prenominal) resistant which allows tracking cell processes for longer periods of time and which will lead to discovery of new molecular interactionsQuantum dots have size dependant waiver which can be modified according to our requirement (from UV to IR range)Fluorescence is seen for longer time when compared to conventional dyes.The extremely small size gives them slap-up flexibility by allowing them using different delivery routes eg. they can be injected as liquid mixtures, fabrics, and polymer.7PROPERTIES OF QDsSome of the properties of Quantum Dots that are used to examine nanocarrier conduct in biological systems are (2, 5,7)Small size size peradventure around 2-10 nm in diameter that en ables tagging of drug/carriers. Single or multi-component systems can be labeled for tracing and monitoringSurface chemistry compatibility with various drug carriers integrating a wide range of nanoparticle drug carrier system.Emission profile identifying quantum dots by its sharp narrow electric arc peak allows simultaneous observation of multiple nanocarriers within a very(prenominal) system.High brightness detection of QDs inside body facilitates the tracing of nanocarriers in vivo.High photostability QDs are more resistant to photobleaching that enables long term real time tracking.QUANTUM DOTS AS NANOCARRIERSQuantum Dots are considered as carriers and the curative drug molecules are directly linked to them to be delivered to the target sites. Here it serves as both vehicle carrying the drug and tracing probe used for the real time monitoring. In drug delivery, size of the Quantum Dots is considered as a very important parameter. The size of QDs varies from 2 10 nm, and it i ncreases to 5 20 nm in diameter after drug encapsulation. It should be noted that QDs of size little than 5 nm are removed in the process of nephritic filtration and those particles bigger is size have problems in penetrating through the tissues and many bigger particles are wiped out before they could reach their destination.Another important characteristics of QDs to be considered for drug delivery is the ratio of surface-to-volume. If this ratio is high thusly multiple carriers can be linked on single QDs without ever-changing the average diameter of the nanocarrier system. Thus the ratio of surface-to-volume should be high.Fig.1 A Multifunctional Quantum Dot coated with Amphiphillic Polymer 6The above figure illustrates that QD acts as essence structural aquaphobic scaffold and the amphiphillic polymer is coated outside the core. The drug molecules which are hydrophobic in nature are embedded surrounded by the core and the polymer coating. And those hydrophilic healthful molecules can be incorporated on the amphiphillic coating. Multiple layers of ligands can be linked in subsequent layers not directly linked to the QD core but to the previous layers of coating and is controlled by them. These nanocarriers also protect the therapeutic molecule or proteins used from the bodys own immune system exoneration mechanism by encapsulating them within themselves. 6Yamomoto et al did research on using quantum dots to treat stroke in and inform that the nanocarriers QD captopril conjugates were capable of move blood pressure in rats. But it was not known whether the therapeutic effect of lowering pressure was due to the conjugate or the uncaring drug from the quantum dots. 6. Not yet drugs, other therapeutic molecules like small interfering RNA, oligodeoxynucleotide and biomolecules e.g. antibodies, peptides can also be incorporated into the nanocarriers. siRNA delivery using quantum dots was reported by Bhatia et al. siRNA moleculeas were boffoly deliv ered using targeted nanocarriers because of the size similarity between QDs and siRNA. Whereas larger molecules like plasmid will require many QDs for successful delivery. 6Mn-doped ZnS Qds encapsulated with glycopolypeptide were fabricated for the drug delivery. Characterization and in vitro studies were make to prove the low cytotoxicity of the nanocarriers and it was good effort for the targeted drug delivery 4.QUANTUM DOTS AS TAGS FOR OTHER dose CARRIERSDue to the unique properties of Quantum Dots, they are used as tags to label other drug carriers and are used as traceable drug delivery. The high photostability helps in the real time tracking of the nanocarrier inside the body. Therefore blind drunk fluorescence signal indicates higher uptake of drug by the cells. The wavelength of the emitted signal depends on the size of the Quntum Dots used. Thus it is very specific to the QDs and thereby simultaneous nanocarriers can be used and the signals can be easily identified.Chen et al. reported about their work of siRNA delivery with QD conjugated with Lipofectamine. The results attested that fluorescence intensity of QD is proportional to the point in time of silencing i.e. if lipoplex uptake is more than the fluorescence will be stronger. 6 Another work done by Zhang et al. reported the synthesis of QD-chitosan conjugate nanobeads for the delivery of siRNA. It was successfully traced because of the mating with QDs. 6 Amphipol nanocpmplex were prepared for the real time imaging of siRNA by Lifeng et al. it was delivered intracellularly and imaged in a real time pattern. 12SYNTHESIS AND CHARACTERIZATIONThere are many ways of preparing Quantum Dots. Some of the noted process of fabricating QDs are Lithography, Colloidal synthesis, Epitaxial methods, some chemical methods 2,10.Generally NDDS is prepared in the following stepspresent many non-toxic semiconductor QDs are used for the drug delivery. Consider for exercising ZnO. It is a non-toxic semiconducto r when compared to other Quantum Dots such as CdS, CdTe. These QDs can be combined with biocompatible and biodegradable polymer to increase the stability and non-immunogenicity of the nanocarriers. It also shields the nanocarriers from the interference of other interacting molecules inside biological environment. Chitosan is a natural copolymer which on encapsulation enhances the quantum dots properties like solubility in water, metal chelation and easy processing and biocompatibility 3.Characterization studies like TEM, UV-VIS, PL spectroscopy, FTIR, Drug release reception test are done after the synthesis. TEM is used to find out the size range of the fabricated QD. PL and PLE spectra give discipline about the emission spectra. FTIR confirms the incorporation of the drug into the QD and Drug release response test gives the amount of drug released and tells about the type of drug delivery. 10, 3. ratiocinationQuantum Dots will be the future of drug delivery systems if the only d rawback has been eliminated. The only disadvantage in using Quantum Dots is their long term toxicity. This can be overcome by replacing the core of the QD with biocompatible agents like gold or magnetic nanoparticles which offers a unique combination of therapy like magnetofection and photothermal treatment. Recent studies show that quantum dots to be safe on primates 9. Quantum Dots will be a powerful tool to diagnose and treat cancer 11. Thus quantum dots will become the new era of drug delivery.