Quantum Dots For Drug Delivery Biology Essay

Quantum Dots For Drug Delivery Biology Essay A drug delivery system can be defined as the mechanism for the introduction of drug and other therapeutic agents into the body for treating any disease. An ideal drug delivery system possesses two elements: (1) the ability to target -to ensure high efficiency and reduce the side effects, (2) controlled drug release (3) prevention of side effects [8]. Using nanomaterials for drug delivery NDD (nanoparticle drug delivery) has the following advantages: reduced drug toxicity better penetration of the particles different delivery routes minimizes the irritant reactions improved bio-availability and increased circulation time controlled drug release and targeting It 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 replacing the existing products with new nanoparticles that are friendly throughout their lifecycle[8],[7]. QUANTUM DOTS FOR NDDS: NDDS 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 are highly suitable for such systems.[1] The important characteristics of Quantum dots which make them suitable for drug delivery systems are: small size, versatility of surface chemistry to incorporate various drugs, unique optical properties for real time monitoring of drug transport and release both at systemic and cellular levels. These Quantum Dots can be used as carriers by integrating with many drugs and also used as tags for other drug carriers. [6] WHY QUANTUM DOTS One of the important reasons why 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 will 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 imaging techniques like MRI and PET, the optical imaging using Quantum Dots is highly sensitive with high resolution and at very cheap cost which will automatically lead to the reduction of time involved in the development of new drug and many discoveries in the field [6]. ADVANTAGES OF USING QDs Optical imaging with high resolution, high sensitivity, multiplexing, and low cost Small size which leads to less amount of drug usage and low drug toxicity Versatile surface chemistry, Improved bioavailability and delivery of drug in a controlled and sustained manner Decreased incidence of side effects and improve patient compliance Comparing other conventional probes, QDs are more resistant which allows tracking cell processes for longer periods of time and which will lead to discovery of new molecular interactions Quantum dots have size dependant emission 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 great flexibility by allowing them using different delivery routes eg. they can be injected as liquid mixtures, fabrics, and polymer.[7] PROPERTIES OF QDs Some of the properties of Quantum Dots that are used to examine nanocarrier behavior in biological systems are: ([2], [5],[7]) Small size: size maybe around 2-10 nm in diameter that enables tagging of drug/carriers. Single or multi-component systems can be labeled for tracing and monitoring Surface chemistry: compatibility with various drug carriers integrating a wide range of nanoparticle drug carrier system. Emission profile: identifying quantum dots by its sharp narrow emission peak allows simultaneous observation of multiple nanocarriers within a same 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 NANOCARRIERS Quantum Dots are considered as carriers and the therapeutic 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 increases to 5 20 nm in diameter after drug encapsulation. It should be noted that QDs of size smaller than 5 nm are removed in the process of renal 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 then multiple carriers can be linked on single QDs without 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 [6] The above figure illustrates that QD acts as core structural hydrophobic scaffold and the amphiphillic polymer is coated outside the core. The drug molecules which are hydrophobic in nature are embedded between the core and the polymer coating. And those hydrophilic therapeutic 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 defense mechanism by encapsulating them within themselves. [6] Yamomoto et al did research on using quantum dots to treat stroke in and reported that the nanocarriers QD captopril conjugates were capable of lowering blood pressure in rats. But it was not known whether the therapeutic effect of lowering pressure was due to the conjugate or the detached drug from the quantum dots. [6]. Not only 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 successfully delivered using targeted nanocarriers because of the size similarity between QDs and siRNA. Whereas larger molecules like plasmid will require many QDs for successful delivery. [6] Mn-doped ZnS Qds encapsulated with glycopolypeptide were fabricated for the drug delivery. Characterization and in vitro studies were done 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 DRUG CARRIERS Due 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 strong 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 showed that fluorescence intensity of QD is proportional to the degree 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 conjugation 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. [12] SYNTHESIS AND CHARACTERIZATION There 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 steps: Nowadays many non-toxic semiconductor QDs are used for the drug delivery. Consider for example ZnO. It is a non-toxic semiconductor 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 response test are done after the synthesis. TEM is used to find out the size range of the fabricated QD. PL and PLE spectra give information 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]. CONCLUSION: Quantum Dots will be the future of drug delivery systems if the only drawback 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.

Abortion Should Not be Banned :: Abortion Pro Choice Essays

The main problem in the world is inevitable abortion. Because it is about morality; which people tend pay more attention. Nowadays, Abortion is a controversial problem as people think of appropriateness. However, Abortion is necessary in many cases. Three main reasons why abortion should be banned are condition that women are not pregnancy, health problem in mother, and social problem. First, the pregnancy without readiness because the teenagers has sexual relation â€Å"premature† because nowadays it has communication is easy and comfortable. It make teenagers can getting to know it easier and sometime the women it may be deceptive in a way that is not good, for example indecent, fraudulent. Especially the pregnancy has not ready is in school because the women may be problem in social is drop out of school (Growing up global, 2005 p.540) Because of poor academic and the lack opportunities in economic not only economic but also is good occupations and social is good the children of mother have not finish it becomes problem side working, such as cheap labor in the factory. Perhaps someone is pregnant in school have an abortion in the school it help open opportunity for continue to study for the future. Sometime, husband and wife the protection of sexual relation has failed from process condom for example using low quality materials. The causes of the family i t reason why want to abortion because not ready take care a baby is born. Secondly, The health of the mother, body of physical disorders of the body. The major reason that abortion should not be banned is for preventing transmission of Human Immunodeficiency Virus (HIV) from mother to infant during pregnancy â€Å"reduce maternal morbidity and mortality† (Rudolph Gurtovnik, 2008, p.28) it is the big problem that the government has to solve and spent a lot of budget to treat all of these people. Some women feel that they have not the economic resources to take care a HIV child. A HIV status may also the cause women to reject their pregnancy. Some women need to restrict their incomes for accessing on a meditation and treatment to family members’ HIV infection. On the other hands, a pregnancy woman also has a negative impact to her health HIV women access abortion because they intentionally choose not to have a child and also fear that their pregnancy would lead to both mother and child poor health and death. Finally, the main clause a big problem of social problem is the accident situation has effect when the women are raped.

Conservation of Natural Resources

We should be proud of our country’s natural bounty and unique bio-diversity. India is amongst the rare countries where major biomes of the world are represented. India is one among the twelve countries where 60-70% of the world’s total biodiversity exists. India has two out of the 18 biodiversity hot spots in the world. India has rich traditional knowledge and wisdom in the conservation of nature and natural resources. Religious beliefs, culture and folklore have together treated nature and environment with sanctity. Conservation and protection of environment and love for nature have always been part and parcel of Indian ethos and culture. Independent India has traveled a long way on the path of progress and industrialization in order to achieve better quality of life. We have accelerated the process of development without considering the adverse impact on nature and environment. The development without care for environment has posed threats to the very existence of life itself. Now the realization that mere progress and economic development cannot solve all our problems has increased. Development and environment should go hand in hand. Sustainable development is the new paradigm. The Ministry of Environment and Forests has drawn many programmes and policies to combat these problems. Steps are being taken to preserve the pristine eco-systems through establishment of Wildlife Sanctuaries, National Parks and Biosphere Reserves. More and newer areas are being brought into-the protected areas status. At the same time, steps have been †¢taken for welfare of the forest people, particularly the tribals, who have lived in the forests for centuries and who are also repository of traditional knowledge on conservation and sustainable utilization. The National Museum of Natural History is an important institutional tool for spreading awareness on the evolution of our Universe and life on it. It has played a strong and active role in creating environmental awareness. I am happy to say that the Museum has been active in creating such awareness hrough a number of educational programmes, exhibitions, nature camps etc. for more than two-and-a-half decades. Today, the Museum and its Regional Centres are recognized as the centres for non-formal environmental education. It is indeed a pleasure for all of us to be celebrating the 25th Year of the Foundation of the Museum. I am happy to see that a number of children have participated in various activities of the Museum. These activities will help all of you in developing a sense of environmental responsibility, which is so essential in our every day life. It is the absence of this responsibility which is causing problems on our streets, residential areas, market places and other public places. This leaves you all – responsible citizens of tomorrow, with a great burden to shoulder. But I am confident that you have the capacity not merely of shouldering this burden but also influencing people much older to you in following environmental discipline. I wish the officers and staff of National Museum of Natural History the very best in their future endeavour. I would like to thank and congratulate Prof. Yash Pal who has delivered his Key-note on the relevant theme. We need such scientists who could contribute to spread scientific temper among masses which will eventually lead to betterment of their lives and better understanding of the delicate web of life that exists on this only planet known to sustain life. I congratulate the winners of Awards for Prevention of Pollution, Rajiv Gandhi Award for Clean Technology and Indira Gandhi Paryavaran Puraskar. The awardees for the best original writings in Hindi on environmental issues also deserve my special appreciation for their efforts in popularization of environmental issues in the official languages. There is dearth of such literature in the regional languages. The Ministry will encourage other regional languages also which will help to take the environmental message to the grass root levels, across the country. I am personally grateful to our Hon’ble Vice President, Thiru. Shekhawatji to have accepted the invitation to grace the occasion. I know that he is keenly interested in the issues related to environment. His own State of Rajasthan is an example of all climate adversities, yet you can see maximum vibrancy of all forms of life that exist there including those of fellow citizens.

Environmental Problems Essay Example

Environmental Problems Essay Example Environmental Problems Essay Environmental Problems Essay Environmental Problems The environment is everything around us. It is the air, water, land, climate and so on. Since many years ago, people interferences with the environment which causes several problems. Some of these problems are air pollution, water pollution, rain forest destruction, smog, overpopulation, and global warming. The worst problems now affecting the world are global warming and overpopulation. First of all, global warming, which means increasing the temperature of the earth, is the most dangerous one. There are many things, which cause global warming. The major reason is pollution, which is one of the man-made problems. In fact, burning fossil fuels is one thing that causes it. When fossil fuels are burning, they give us a greenhouse gas called Co2. After that, the greenhouse, which traps heat and light from the sun, will increase; as a result, the temperature rises. This happens because the heat and light can get through the atmosphere, but it can’t get out. Depending on the scientists, there are two major effects of global warming. One of them is rising of sea levels, which kills people, plants, and animals. The other one is an increase of the frequency, duration, and intensity of weather events, such as floods, droughts, heat waves, and tornadoes. Second is overpopulation. The population of the world has been gotten up for years. The population is almost reaching the stage where there are too many people for planet to support. The huge numbers of people consume more items, drive more cars, and create larger amounts of garbage. Consequently, we are putting more carbon dioxide into the atmosphere, which increases the global warming problems. Thus, overpopulation is the worst environmental problems. Indeed, communities now are aware of the environmental problems and they are trying to do more research, and find suitable solutions for its. They are doing the best especially with overpopulation which leads to the biggest issues for the earth.

Key Quotations Assignment Essays

Key Quotations Assignment Essays Key Quotations Assignment Essay Key Quotations Assignment Essay Leak entertains Stephan with stories from his memory but whenever Stephen listens to them, he feels as though he is sees of a man for being interested which demeans the way he sees himself. The image of what is expected to be a man [As he] observed the easy strength Of these men, the more certain he was that he was that he could never become a man had been imprinted in his mind because he was surrounded by people that he was expected to live up to and become. His father expects him to become strong and work as a pulp cutter. Stephen sees the image of what he is supposed to live up to and because of it, he was expected to scorn now that he was becoming a man compelling him to abandon his childish nature. Nolan emphasizes on the internal conflicts that Stephan has within himself by creating a kind of push and pull scenario for Stephan to overcome. On one hand, the stories that Leak tells Stephen keeps him entertained and happy but on the other hand, Stephan is expected to live up to his father expectations and fill in his shoes. He is forced to choose between his own desires which are his child-like side or adapt to the conformity to gain his fathers respect. Theme: Mayo try to hard kid. The Pollack murmured. You act as if the saw were the most important thing in the world. One of the targeted themes of the story as that becoming a man isnt everything. Throughout the first half of the story, Nolan showed that Stephan had internal conflict within his own mind as he had a difficult time denying his identity for the acceptance of his father, but as the story progressed, with the help of Leak, he began accepting who he is. He began to consider what Leak had to say and thought about something other than what his father wanted. He began thinking of his own desires and choices instead of having such a narrow mind and thinking of being something other than being a man just because his father wanted him to. He accepted the fact that being a man isnt the most important thing in the world. Nolan shows us the importance of being able to think for yourself and fighting against conformity and pressure allowing the open mind of possibilities and alternatives. Stephan sees that he can be more than just a pulp cutter. He also sees that he is trying too hard to be something he is not, which was what created that internal conflict within himself and comparing his own inadequacy to another. Symbol: In our house in Transpolar, there were glass roses. Pretty little flowers made of red glass. My mother was very proud of them. She would let no one touch them When the first bomb fell, farther down the street, the glass roses were shaken from the mantel and they fell on the floor and broke in a million pieces. There is not much room in the world for glass roses This quotation shows Nolan allowing the destruction of a beautiful glass rose. Through Leaks stories, Nolan uses the glass rose as a representation of Stephens innocence as it is considered beautiful and kind like the glass rose. As Stephen struggles with his inner conflict between manhood and childhood, he is torn between conformity and his innocence. When Leak said the glass roses were shaken from the mantel and they fell on the floor and broke into a million pieces, Nolan was talking about Stephens innocence and possibility of a broken childhood, if it were to be shaken, it would [brake] into a million pieces. This shows that if there were to be instability with Stephen, such as manhood and the pressure of it, it would overcome the fragility of his innocence and destroy the beauty of his identity, desires and himself. The glass rose also represents the friendship that Leak and Stephen have. When We think of a glass rose, We think Of love and beauty and because Leak acts as a shining beacon of hope for Stephen and that creates a beautiful friendship. Stephen learned to become more than what his father wanted him to be by acknowledging the fact that he was very proud of them. Stephen came to the conclusion that Leak was his friend and that means he should stand up for his friend. By doing so, Stephen overcame his inner conflicts whether he should follow in his fathers footsteps or his own. Stephen also acknowledges that there is not much room in the world for glass roses so once he overcame his weakness, he was able to prevail onto utter things such as pursing his desires within himself. Setting: Streaks of daylight were appearing on the black forested, snow- shrouded horizon. The wind had fallen somewhat but it was still raw enough to lacerate Stephens temples The setting Nolan created inferred that Stephen was isolated with nothing but negative influence and pressure from his peers and especially his father that is forced upon Stephen. The story is placed in a dark isolated forest where Stephen is forced to work every day in it but with streaks of daylight appearing on the black forested, snow-shrouded orison. It is used as a beacon of hope that shines in the dark for Stephen when everything else seems so bleak and misguided. The forest is used as kind of a sense of a barrier or shield for Stephen between him and the outside world as the wind had fallen somewhat but it was still raw. Stephen s perception of himself his fixated in the reflection of others but the light not only shows him hope but it also shows that when in the forest, Stephen feels as though his dreams are valid even in the dark. Throughout the day, Stephen is forced to face the disappointment in his fathers eyes hen his father sees Stephen as not a man creating an emotional impact on him. By creating the setting in the forest, it is Stephens way of trying to escape all the expectations and what he is supposed to live up to. Point of view: He thought of the dozens of trees he would have to fell before the end of the day, millions of trees he would have to fell before he died. For as long as he lived, he would kneel beside a tree, a slave to the monotonous rhythm of the pulp saw Throughout the story, Nolan slowly progressed with expressing more and more of Stephens point of view. In the beginning it showed that it was as if Stephen didnt have a point of view to begin with. Everything was so fixated with his fathers perspective on things that it blinded his own vision of his own dreams. This quote not only shows Stephens point of view but it also shows Stephens feelings for as long as he lived he would kneel beside a tree, a slave to the monotonous rhythm of the pulp saw. Stephen projects the thought of having to follow in his fathers footsteps in a negative light displaying a small sense of emotion, he feels as though the life he is living isnt he life he wants but rather the life that his father has built up for him and that worries him.

Objection Essay Example | Topics and Well Written Essays - 1000 words

Objection - Essay Example Consequently, the paper also discusses how appellate court will rule on the objection. The outcome of the alcohol test was issued as one of the evidence (Krey & Theresa, 75). According to the judge, if Fred Friendless has a blood content of 10, they must presume that Fred Friendless is intoxicated. Therefore, obtaining a conviction for Driving while intoxicated, the prosecution will need to establish that Fred Friendless was actually operating the vehicle under the influence. This will be accomplished through circumstantial evidence or by the witness of the eyewitness. From Fred Friendless case, the court will review the Driving While Intoxication conviction where Fred Friendless’ prosecution will prove that he was driving the vehicle. Evidence from the high school head teacher revealed that he measured the skid mark of the defendant and assumed the defendant was driving at least 65 miles per hour. Additionally, the defendant believes that the any person who drinks at least two beers already intoxicated. This is a direct prove that Fred was actually driving under the influence of alcohol (Dolinko,  67). The evidence does not establish that the defendant was under the physical control of the car and hence it is not sufficient to prove that Fred was driving the vehicle. The prosecution also needs to establish the intoxication, which he did not. According to the statutes, it is noted that, intoxication normally occur due to alcohol intake of contraband ingestion. Intoxication is normally hard to articulate. In addition to submitting the blood sample, the police needs to testify the speech, appearance, or behavior and if the police detected the smell of the alcohol beverage on Fred. The factors are important and pertinent evidence of the physical impairment and mental impairment of the defendant. During Berkemer v. McCarty 468 US 420, the Supreme Court believed that the police roadside

American Environment History Essay Example | Topics and Well Written Essays - 250 words

American Environment History - Essay Example tury and even felt to date whereby some especially the preservationists led by Muir termed those supported â€Å"wise use† of natural resources for humanity’s benefits as â€Å"temple destroyers† (Fitzsimmons 13). This is evident specifically when the two sides disagreed on damming Tuolumne River in Yosemite National Park to act as a reservoir with the intention of availing water supply to San Francisco city (Fitzsimmons 13). Pinchot’s idea encompassed the then dam that was basis of argument after completion and effective management to flood Hetch Hetchy Valley and in turn avail necessary water to the city dwellers (Chapman). Hence, aligning with what he cited as â€Å"wise use† of resources not only during then but also in future whereby currently San Francisco continues to depend on this water supply. This was after Pinchot’s idea received massive congressional approval for complete construction in 1913 (Fitzsimmons 13). Consequently, this brought about Western Civilization ideals of utilizing natural resources with the intention of benefiting from them though with consideration of their sustenance despite being anti Muir’s argument. This is because Muir on his part termed natural resources as sacred thus referring Hetch Hetchy Valley as â€Å"shrine† and those of contrary opinion were holding perfect contempt against nature (Fitzsimmons 13). Chapman, Ann, E. American Conservation in the Twentieth Century. National Park Service. n.d. Web. 27Th October 2013.