Part 2

Question 1

What is cancer metastasis?

Answer 1

A cancer that has spread from the part of the body where it started to other sites.

Question 2

What are the issues with current cancer chemotherapy?

Answer 2

• Short half life
• Very small therapeutic window
• Wide distribution in healthy tissues and organs
• Off target, assaults normal cells with serious side effects (toxicity, weakened immune system)
• Limited effectiveness

Question 3

What is a liposome?

Answer 3

A spherical vesicle having at least one lipid bilayer. It can be used as a vehicle for the administration of nutrients and pharmaceutical drugs. They can form lipid bilayers because of their amphiphilic characteristic. consists of fatty acid (hydrophobic) tails and hydrophilic heads (phosphate group)

Question 4

List the advantages of nanotechnology for cancer therapy

Answer 4

• Improved drug half life

- Targeted delivery

Question 5

What is a receptor?

Answer 5

A receptor is a molecule most often found on the surface of a cell. which receives chemical signals originating externally from the cell. Through binding to a receptor these signals direct a cell to do something.

Question 6

What is the Enhanced Permeability and Retention (EPR) effect?

Answer 6

the property by which certain sizes of molecules (typically liposomes and NPs) tend to accumulate in tumour tissues much more than they do in normal tissues. Magnetic NPs typically better accumulate in tumour region with the aid of a magnetic field.

Question 7

What is the general explanation for EPR?

Answer 7

In order for tumour cells to grow quickly, they must stimulate the production of blood vessels.

Question 8

List the positives for using PEG to coat the surface of nanomaterial

Answer 8

• Soluble in organic polar an a polar solvents and water
• Stable, inert and biocompatible
• Avoids non-specific absorption
• PEG-modifed drugs have better water solubility and decreased immunogenicity.

Question 9

Give an advantage of using QDs for biolabelling

Answer 9

Fluorescent semiconductor QDs have significantly higher stability than conventional fluorescent dye

Question 10

What property of QDs make them interesting (hint: colour)

Answer 10

Fluorescent semiconductor QDs have narrower emission, broader absorption range. The same material can have distinct emission colour by simply tuning the size of the QDs.

Question 11

Why are silver ions used for antibacterial applications?

Answer 11

Silver IONS and silver based compounds are highly toxic to microorganisms. Silver NPs can be used to kill bacterial. The size and shape of silver NPs can affect the killing with smaller being more efficient.

Question 12

Why are smaller nanoparticles more efficient at killing bacteria?

Answer 12

Silver particles without oxidation do not kill bacteria. After silver NPs are oxidised to silver ions, they can effectively kill bacteria. Small NPs are oxidised more efficiently and therefore kill bacteria better.

Question 13

What are paramagnetic materials?

Answer 13

Materials that are slightly attracted by a magnetic field and the material does not retain the magnetic properties when the external field is removed.

Question 14

Why do paramagnetic properties occur?

Answer 14

Occur due to the presence of some unpaired electrons.

Question 15

Wh ado paramagnets not retains any magnetisation once the magnetic field is removed?

Answer 15

Because of thermal motion randomises the spin orientations.

Question 16

What is superparamagnetism?

Answer 16

A form of magnetism that appears in small ferromagnetic NPs.

Question 17

What is MRI used for?

Answer 17

Used in radiology to visualise internal structures of the body in detail.

Question 18

What does the operation of MRI rely on?

Answer 18

MRI machines make use of the fact that body tissue contains lots of water and hence protons which get aligned in a large magnetic field.

Question 19

What is the mechanism for MRI?

Answer 19

In the external magnetic field, the proton nuclei of hydrogen atoms in tissues are raised to a higher state of energy when exposed to a short pulse of radio frequency (RF) radiation.
When the pulse is turned off, excited hydrogen protons emit RF energy as they return (relax) to their original energy state. the RF signal is detected and an image is built.

Question 20

What are the 2 mechanisms for hydrogen relaxation?

Answer 20

T1 (spin-lattice) relaxation time, quantifies the rate of transfer of energy from the nuclear spin system to the neighbouring molecules. Relaxation in the z-direction

T2 (spin-spin) relaxation quantifies the rate of decay of the magnetisation within the xy plane.

Question 21

How is contrast achieved in an MRI?

Answer 21

Protons in different tissues return to their equilibrium state at different relaxation rates. This effect can be used to create a contrast between different types of body tissue or between other properties.

Question 22

What is added to improve MRI contrast?

Answer 22

If simple differences between T1 and T2 are sufficient to build a contrast picture, contrasting agents can be added. These are paramagnetic chemicals that localise in certain tissue/fluids and artificially change their spin relaxation properties.

Question 23

What is the problem with contrasting agents and what is the solution?

Answer 23

Contrasting agents are chemicals with at least one free, unpaired electron.Most metals with unpaired electrons are heavy metals (TOXIC). To reduce the toxicity metals can be complexed with ligands. This prevents them interacting biochemically with organs.

Question 24

What is a disadvantage to organic sunscreen?

Answer 24

Limited wavelength absorbance, need multiple ingredients to achieve full spectrum absorbance.

Question 25

What is an advantage of nanoparticle sunscreen?

Answer 25

Large spectrum of light absorbance with a single particle.

Question 26

What is Mie theory?

Answer 26

The scattering of visible light (whitening effect) is influenced by particle size and the difference between the refractive index of the pigment and the surrounding media.

Maximum scattering occurs when size equals 1/2 the wavelength and particles are uniformly dispersed (Mie theory)