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  • Medicine matters.

  • Whether you're getting a flu shot or just taking an aspirin, the medical field is vital to the way you live your life.

  • New treatments are coming out nearly every day, all because of the hard work of scientists and engineers.

  • Together they're creating breakthrough medicines and figuring out how to get them where they need to go.

  • These efforts are known as drug discovery and drug delivery, and they're what you need if you want to engineer a healthier world.

  • [Theme Music]

  • In today's world, it's pretty easy to get things with a personalized touch.

  • Everyone's different, and people want a lifestyle that reflects those differences.

  • Custom cars, tailored clothes, personalized electronicsthe list goes on.

  • But what about medicine?

  • What if you could walk into a hospital and get a completely personalized treatment for whatever you had going on?

  • That's the dream of biomedical engineering: a world where doctors can diagnose and treat a person based on their individual differences.

  • This concept is called personalized medicine and it's the healthcare of the future.

  • It's the idea that you could combine a person's genetic information with clinical data to best tailor a treatment to meet their specific and unique needs.

  • Medicine is the field where all our knowledge comes together.

  • You'll need biology to understand the problem, chemistry to figure out the solution, and physics to deliver that solution in a safe and targeted way.

  • As an engineer, it's your job to bring all this together using concepts like biocompatibility and fluid flow to create one easy-to-use package that could save someone's life.

  • Lucky enough, there's already some places where this kind of personalized approach is being used!

  • For instance, genetic tests can reveal how likely someone is to get breast cancer and guide them onto an appropriate monitoring path early in life.

  • Hopefully this leads to detecting the disease early on, when treatment options are less invasive and more successful.

  • But there are still many challenges to overcome before personalized medicine becomes widespread.

  • You need to develop better systems to quickly assess a patient's genetic profile,

  • create inexpensive diagnostic devices using that information, and find the best way to deliver a drug if anything comes up.

  • And that's all after your come up with a good treatment in the first place!

  • Drug discovery is all about finding that new treatment.

  • It's the process through which you discover and create new medications based on what you know about your ingredients and how they'll interact with the human body.

  • Even before modern healthcare, people found natural remedies, often by chance, that improved their health or helped them get over an illness.

  • The early days of drug discovery were all about finding the active ingredients inside those remedies

  • the part that was actually affecting the bodyand learning how to replicate or improve on the outcome.

  • Hot peppers, for instance, were used for centuries to relieve the pain of things like toothaches,

  • but today we know it's only the substance capsaicin that matters.

  • You can now buy it to treat conditions such as arthritis and shinglesall without the burning sensation created by other parts of the pepper!

  • These days we have large chemical libraries of synthetic molecules, natural products, and chemical extracts that |have been tested to determine their effects.

  • This is called classical pharmacology.

  • A new tool is genome analysis, the study of a complete set of an organism's DNA, including all of its genes.

  • It's the result of the Human Genome Project, which successfully sequenced our DNA.

  • Sequencing your genome is like mapping out all the genes in your body.

  • It's about figuring out the order of all the DNA nucleotides, or bases, in your genome.

  • For the Human Genome Project, researchers were able to sequence all of our 3.2 billion base pairs,

  • which allowed for the rapid cloning and synthesis of large quantities of purified proteins.

  • Genome analysis is the foundation of the modern approach to developing drugs, called reverse pharmacology.

  • Reverse pharmacology starts by identifying which of those proteins is related to the condition you want to treat.

  • You can compare that protein to a list of chemical reactions to find a molecule known to interact with it.

  • If you find a match, you can test the substance on living cells to see if the reaction has any positive impact.

  • From single cells, you can move up to simple animals andif all goes welleventually to human trials.

  • By starting with theproblem areaand working backwards, reverse pharmacology is the more educatedand often fasterway to discover a new medicine.

  • Regardless of which way you got it, once you have a treatment, it's on to drug delivery:

  • getting the medicine to move through the body, find the site of the problem, and even attach to right parts of the cells.

  • Syringes are the classic solution to this problem.

  • Just draw up some medicine and inject it right where it's needed.

  • But those syringes used to need a lubricant to help the plungerthat thing you press down onwell, go down.

  • This usually meant using silicon oil, which could be a problem.

  • Silicon oil can react with the medicine inside and, as medicines have become more and more specialized, the worse and worse the reactions can be.

  • Many drugs also can't be delivered straight to the bloodstream, but have to be metabolized in the stomach or intestines first.

  • So it's a good idea to have other options for delivering your drugs.

  • We've talked about some possibilities before, such as nanomaterials or biomaterials.

  • Researchers are currently exploring ways to engineer nanoparticles that could deliver a drug to its target in the body while evading your immune system's normal defenses.

  • You've heard about smartphones and smart cars, but what about smart medical devices?

  • The idea is to design something that's sensitive to the body's internal conditions, letting the drugs react in the right way at the right times.

  • Take someone with diabetes, for example.

  • You could design smarter devices with better materials so that insulin was only released into their system when their blood glucose levels were too high.

  • In the new field of tissue engineering, researchers are combining the principles of biology

  • with the applications of engineering to create novel biomaterials that could aid in the repair of damaged body tissuesmaybe even replace them!

  • One goal is a type ofmedical scaffoldthat can attract stem cells and guide their growth into specific types of tissue using biological signals.

  • Stem cells are the building blocks of the body.

  • And, in the future, mastery of synthetic tissue engineering could make it possible to regenerate tissues and even entire organs.

  • That's about as personalized as it gets!

  • Even that doesn't cover the full spectrum of what we want medicine to do.

  • Sometimes the problem isn't that you're trying to repair or regenerate the body,

  • but rather that you're trying to stop something from spreading or growing in the first place.

  • Cancer is the second leading cause of death worldwide, and it's responsible for millions of deaths every year.

  • Conventional treatments generally rely on a combination of surgery, radiation, and chemotherapy.

  • Chemo is often the first choice for treating many types of cancer, but it's basically a poison that you hope kills the cancerous cells faster than the healthy ones.

  • It's a similar story with radiationit's hard to limit its effects to just the bad cells.

  • With conditions like these, a drug delivery system that only gets the treatment generally where it needs to go isn't good enough.

  • You need to have a targeted drug delivery and not hurt anything else along the way.

  • This enables you to maximize the positive effect at a specific place in the body with few negative side effects elsewhere.

  • It would also allow you to treat hard-to-reach places while also using smaller doses.

  • The idea of thismagic bulletapproach has led to a number of new drug carrier systems.

  • A great example of these are direct local delivery systems, like the skin patch.

  • These patches can slowly release medicine into the body over a period of days.

  • They're commonly used to administer birth control or help smokers with nicotine withdrawal.

  • A drug-eluting stent, which is a mesh tube that delivers time-released medicine, can do the same thing from within the body.

  • They're often implanted into patients with coronary artery disease to prevent dangerous blockages.

  • Another promising tool is microparticles.

  • They're small enough to travel through the heart as part of the bloodstream, yet big enough that they can't enter capillaries.

  • A number of researchers have taken this unique property and prepared biodegradable drugs made of things like starch.

  • They can deliver a large dose of chemotherapy directly to a targeted site, a process that's also called chemo-embolization.

  • The particles accumulate at designated spots in the body, kind of like a storage depot.

  • As they break down, the drugs release slowly, but continuously into the targeted area.

  • Want to speed up or slow down the release rate of the medicine?

  • Try using a different materialone that degrades at a different speedor design the particles to have bigger or smaller pores.

  • But let's say you do want something that can enter the capillaries so that it can keep on circulating through your body.

  • Then nanoparticles are the way to go.

  • Particles around 110-140 nm in size seem to be ideal for most applications

  • because they're large enough to avoid being cleaned out by the liver or kidneys, but small enough not to be attacked by white blood cells.

  • The goal is for them to stay in the body's circulation long enough to be removed by the target tissue rather than something like your immune system.

  • This approach might be especially well suited to treat cancer.

  • Since the blood vessels connected to tumors are often quite large, the medicine is less likely to leak into surrounding tissue,

  • resulting in something called the enhanced permeability and retention, or EPR, effect.

  • Basically, you're increasing how much medicine gets to where you want, while reducing it where you don't.

  • Future techniques could be even more accurate.

  • An idea currently being developed is microbubbles, which are super small bubbles filled with gas.

  • Someday they could hold a chemotherapy drug that would only be released when the bubbles experience the waves of an ultrasound.

  • The ultrasound would target a specific part of the body and burst only the microbubbles at the site of the tumor,

  • which would activate the drug only where it's needed most.

  • Targeted carriers like these, along with good disease detection systems and a wealth of drug discoveries, will add up to that promised world of personalized medicine.

  • Today we learned about drug discovery and drug delivery.

  • We covered classical and reverse pharmacology, as well as the new field of synthetic biology and what people have been able to accomplish with it.

  • Finally, we saw how important good disease detection is and why we need more targeted drug delivery systems.

  • I'll see you next time, when we'll go one step further and talk about biodevices.

  • Crash Course Augmented Reality Poster available now at DFTBA.com

  • Crash Course Engineering is produced in association with PBS Digital Studios, which also produces Global Weirding,

  • a show that explores the intersection among climate, politics, and more, hosted by climate scientist Katharine Hayhoe.

  • Check it out at the link in the description.

  • Crash Course is a Complexly production and this episode was filmed in the Doctor Cheryl C. Kinney Studio with the help of these wonderful people.

  • And our amazing graphics team is Thought Cafe.

Medicine matters.

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健康をエンジニアにする方法 - 創薬とデリバリー。クラッシュコースエンジニアリング #36 (How to Engineer Health - Drug Discovery & Delivery: Crash Course Engineering #36)

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    林宜悉 に公開 2021 年 01 月 14 日
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