Chemistry in Medicine

Major contributions to health care have been made by chemistry.  The development of new drugs involves chemical analysis and synthesis of new compounds.  Many recent television programs advertise the large number of new drugs produced by chemists.

Figure 1. Drug for treatment of disease.

The development of a new drug is long and complicated.  The chemistry of the disease must be studied, as well how the drug affects the human body.  A drug may work well in animals, but not in humans.  Out of a hundred drugs that look like they help treat a disease, only a small handful actually turns out to be both safe and effective.

Chemistry contributes to the preparation and use of materials for surgery (sutures, artificial skin, and sterile materials).   The sutures used in many surgeries today do not have to be removed, because the simply dissolve in the body after a period of time.  Replacement blood vessels for heart and other types of surgery are often make of chemicals that do not react with the tissues, so they will not be rejected by the body.  Artificial skin can be used to replace human skin for burn patients.

Figure 2. Surgical procedure.

Clinical laboratory testing uses a wide variety of chemical techniques and instrumentation for analysis.  Clinical laboratory testing allows us to answer commonly asked questions such as “is your cholesterol to high?” and “do you have diabetes?” Some of the laboratory tests use simple techniques.  Other processes involve complex equipment and computer analysis of the data in order to perform measurements on large numbers of patient samples.

Figure 3. Blood samples for laboratory testing.

Laboratory testing has come to the local drug store or grocery store because of developments in chemistry.  You can test your blood glucose using a simple portable device that runs a chemical test on the blood sample and tells you how much glucose is present, allowing a diabetic patient to regulate how much insulin to administer (chemistry is also used to produce the insulin and the disposable syringe that administers the drug).

Figure 4. Blood glucose testing device.

Agriculture

How does chemistry aid the success of crops?

In the spring, many people begin to plant their gardens.  They see ads in catalogs or shop the gardening section of a local store to get ideas.  The right place in the garden is selected, seeds or plants are put in the soil, and then the wait.  Whether it is a small home garden or a large thousand acre farm, chemistry contributes greatly to the success of the crop.

Crops need three things for good growth: water, nutrients from the soil, and protection from predators such as insects.  Chemistry has made major contributions in all three areas.  Water purification uses a number of chemical and physical techniques to remove salts and contaminants that would pollute the soil.  Chemical analysis of soil allows the grower to see what nutrients are lacking so they can be added.  In the spring, grocery stores, hardware stores, and gardening centers have high stacks of bags containing fertilizers and weed killers that enrich the soil and keep down unwanted plants.  These same stores also provide a number of sprays or solid treatments for insects that might otherwise have a snack on the plants.

Figure 5. Idaho wheat field.

Water Purification  

Figure 6. Desalinization equipment.

Fresh water is essential for good crops.  In some areas of the world, there is enough rain to accomplish this task.  In other locales, water must be provided so the crops will grow.  Worldwide, irrigation covers about 18% of farm land and produces some 40% of crops. A major source of cleaner water in many parts of the world is provided by the process of desalinization .

Sea water is treated to remove salts and the resulting water can then be used for irrigation without contaminating the soil with materials that harm the growing plants.

Soil Nutrients

Figure 7. Man spreading chemicals on soil.

In many areas of the world, the soil is deficient in essential nutrients.  A number of minerals such as phosphorus, potassium, calcium, and magnesium may not be present in large enough amounts to cause good plant growth.  Nitrogen is extremely important for good crops.

Soil analysis is available from a variety of labs.  Local university extension services can provide valuable information as to the composition of a soil and will also make suggestions as to the types and amounts of needed nutrients.  Fertilizers can be purchased and added to the soil to enrich it and ensure better yield of crops.

Insect Control

Even if the crop grows well, there is still the possibility of insect or pest damage.  The insect or pest can consume the crop or can damage it to the point where it will not grow well.  Infestations of armyworms can do major damage to corn and grain crops. Aphids and boll weevils are major predators of cotton crops.  Failure to control these pests will result in widespread crop damage and financial loss to the farmer.

A wide variety of pesticides have been developed by chemists and other scientists to deal with all these pests.  The basic approach is to have the pesticide interfere with some biochemical process in the pest.  Ideally, the pesticide will not affect other living organisms, but this is not always the case.  It is very important to read the labels and observe all precautions when using pesticides.

Materials

Electronics  

Figure 9. Calculator with liquid crystal display.

Chemists are involved in the design and production of new materials.  Some of the materials that chemists have helped discover or develop in recent years include polymers, ceramics, adhesives, coatings, and liquid crystals.  Liquid crystals are used in electronic displays, as in watches and calculators.  The silicon-based computer chip has revolutionized modern society and chemists have played a key role in their design and continued improvement.  The calculator shown below uses both a liquid crystal display and chips inside the device.

Superconductors

Many chemists are currently working in the field of superconductivity.  Superconductors are materials that are able to conduct electricity with 100% efficiency, meaning that no energy is lost during the electrical transmission, as happens with conventional conducting materials like copper cable.  The challenge is to design materials that can act as superconductors at normal temperatures, as opposed to only being able to superconduct at very low temperatures.

Clothing

Figure 10. Nylon spatula.

The fibers that compose the materials for our clothes are either natural or human-made. Silk and cotton would be examples of natural fibers. Silk is produced by the silkworm and cotton is grown as a plant. Human-made fabrics include nylon, orlon, and a number of other polymers. These materials are made from hydrocarbons found in petroleum products. Synthetic polymers are also used in shoes, raingear, and camping items. The synthetic fabrics tend to be lighter than the natural ones and can be treated to make them more water-resistant and durable.

Materials originally developed as textiles are finding a wide variety of other uses.  Nylon is found in a number of plastic utensils.  Taking advantages of its strength and light weight, nylon is a component of ropes, fishing nets, tents, and parachutes.