These are the outlines of the Learning objectives covered in the Nanomedicine V2 – Lung Cancer Module.
1. How the Lungs work:
Breathing is the way that oxygen is taken into our bodies and carbon dioxide removed.
When we inhale, air travels down the trachea and enters the lungs through the bronchi. The bronchi branch into the lobes of the lungs and divide to form a network of bronchioles.
At the end of the bronchioles are air sacs called alveoli. These sacs are covered in tiny blood capillaries which create the interface where oxygen diffuses out of the air sacs into the blood and where the carbon dioxide leaves the blood and enters the alveoli to be removed from the body when we exhale.
The alveoli are the site of gaseous exchange and are efficiently adapted to do this by: having thin permeable walls (to allow a short pathway for diffusion), a moist lining – in which oxygen dissolves first before it diffuses through, a large surface area, a good supply of oxygen and a good blood supply.
2. Analyse cells:
There are various cells that make up the organs in our bodies.
In the lung’s alveoli there are two main kinds of cell: Type I Pneumocytes and Type II Pneumocytes. Type I Pneumocytes are responsible for gas exchange occurring in the alveoli. This cell cannot replicate and is very susceptible to toxic damage. They cover about 95% of the surface area of the alveoli. Type II Pneumocytes are responsible for the production and secretion of surfactant, a ‘surface acting agent’ that allows for easier gas exchange (they make the surface of the alveoli moist so that oxygen can be absorbed quicker and easier into the blood stream). They cover about 5% of the surface area of the alveoli.
The Bronchioles are primarily made up of Clara cells that are dome-shaped and have short microvilli. Clara cells have many functions. One is to detoxify harmful substances inhaled into the lungs. They also protect the bronchiolar epithelium, the tissue that lines the surface and can multiply and change their cell type to regenerate the bronchiolar epithelium.
Every cell in the body is made up of organelles which are specialized subunits with specific functions.
Nucleus: The Nucleus contains DNA, the genetic component of the cell. DNA is arranged in a highly organized way called chromosomes, otherwise it wouldn’t fit into a cell! Every cell at some point in its life cycle has a nucleus that contains the same DNA encoding every gene in your body, but only the genes needed by that cell at that time are expressed or ‘transcribed’. The nucleus also contains a nucleolus where the proteins (called ribosomes) needed to ‘translate’ DNA into proteins are manufactured before being shuttled into the cytoplasm or to the endoplasmic reticulum
Rough Endoplasmic Reticulum: Ribosomes can associate with the surface membrane giving it a studded or ‘rough’ appearance. The rough endoplasmic reticulum produces proteins that can either be used within the cell or are excreted from the cells.
Smooth Endoplasmic Reticulum: The Smooth Endoplasmic Reticulum has no ribosomes associated with the membrane. Its role is to manufacture lipids such as cholesterol and carbohydrates such as glycogen.
Golgi Apparatus: Proteins produced by the ribosomes in the rough endoplasmic reticulum are surrounded by vesicles and shuttled to the Golgi Apparatus where they are processed and packaged. The Golgi apparatus can also modify proteins by adding carbohydrate or lipid molecules to them. The proteins are now functional and leave for their final destination: secreted from the cell, incorporated in the cell membrane or retained for use within the cell.
Mitochondria: Mitochondria are the power stations for the cell. They produce and supply energy for cell. Cells that require more energy (e.g. muscle cells) can produce more mitochondria.
Centriole: A Centriole is a barrel shaped organelle where the walls of each Centriole are usually composed of nine triplets of microtubules. Centrioles play a large role in cell division by rearranging the internal scaffolding of the cell during replication and determining the orientation of cell division.
Cell Membrane: The Cell Membrane is a lipid bilayer found on all cells and is involved in many cellular processes. It contains proteins and lipids and separates the inside of the cell from the outside in a similar function to skin. The cell membrane is dynamic and plays a crucial role in allowing substances to gain entry to the cell or keeping them out. The surface of the membrane has different types of receptors and gates that are highly specialized for each cell and can be very specific about what can gain entry. Most molecules are not able to penetrate the membrane and so depend on the different mechanisms the cell to be internalized.
Cell Wall: animal cells don’t have a cell wall
Lysosomes: Lysosomes pinch off from the Golgi and contain enzymes that act as an intracellular digestive system and are able to digest fats, nucleic acids, proteins and polysaccharides (sugars). Endocytic vesicles which contain material such as bacteria from outside of the cell can fuse with lysosomes to enable digestion of their contents. Lysosomes can also exert their function outside of the cell. If a tissue is damaged the lysosomes rupture and the enzymes within can digest both damaged and healthy cells.
3. Understand cancer at a cellular level:
Cancer cells ignore a process called apoptosis (programmed cell death) and continue to multiply. As they divide, cancer cells can acquire new and different mutations or deletions which can damage the body. The cancer will get progressively worse if not treated or controlled and is often lethal. Cancer cells will damage normal, healthy cells as they grow out of control, stealing nutrition from the healthy tissue and giving off toxic substances which can damage or kill the healthy cells. The tumour can develop its own blood supply which enables cells to travel through the blood stream to distant locations where the cancer cells can begin to divide. This is called metastasis and means that tumours can form deep within the body because the cells can travel anywhere by hitching a ride with the blood. These tumours can be very difficult to locate and treat because they can occur anywhere. When cancers metastasize to other parts of the body it makes the cancer much more difficult, if not impossible to treat.
All cancers are caused by something going uncontrollably wrong in the cell. Abnormalities like mutations, deletions or even the insertion of extra genetic material (like when a virus integrates its DNA into your own) can all cause normal cells to transform into cancer cells. Every cell has several mechanisms for preventing mistakes occurring in the DNA but sometimes a mistake goes undetected, or an external factor causes a change in the cell. There are many substances called carcinogens, such as tobacco smoke, radiation, chemicals, or infectious agents which are known to turn healthy cells into cancer cells. Other cancer-promoting genetic abnormalities may be randomly acquired or they are inherited, and thus present from birth.
4. Understand Nanomedicine by building a vesicle to help defeat the cancer:
Nanomedicine is the medical application of nanotechnology. It covers areas such as nanoparticle drug delivery and possible future applications of molecular nanotechnology (MNT) and nanovaccine.
Man-made vesicles are relatively small intracellular, membrane-enclosed sacs that can store or transports substances – for example a toxic substance that can be used to kill cancer. Vesicles can fuse with the plasma membrane of a cancerous (or healthy) cell before releasing their contents.
Vesicles are made up of different ingredients, and it is by choosing the right combination that can be the difference between success and failure.
The main elements include the base unit that will contain the substance to be transported, the ‘keys’ that will help the vesicle attach to the receptors on the cells within the body, and the cloaking protections that will help disguise the cell from the body’s white blood cells.
By watching the vesicles travel through the blood stream and attach to cells you can see how they effect the surrounding area with their substances. Only by observing the body and cancer cells and their receptors is it possible to create a viable vesicle that may work, however you will need to take money and number of vesicles into account – too many vesicles can destroy to many healthy cells and kill the patient, too few will do little harm to the cancer cells and be a waste of your research money.