CNTs

Question 1

define the structure of CNTs?

Answer 1

strip of a graphene sheet rolled into a tube

Question 2

how are CNTs made?

Answer 2

1. arc discharge - using graphite
2. chemical vapor deposition (CVD) - using hydrocarbon and metal catalysts
3. laser ablation - graphite + laser - SWNT

Question 3

what are the type of CNTs?

Answer 3

single-walled CNTs (SWNT) - one layer graphite
multi-walled CNTs (MWNT) - several graphite concentric layers

Question 4

describe CNT properties

Answer 4

ordered structure
extraordinary mechanical properties
electrostatic properties
metallic
semiconducting-insulating

Question 5

what are the main issues with CNTs?

Answer 5

insoluble in any organic solvent or aqueous solution

Question 6

what is CNT functionalism?

Answer 6

addition of functional groups to CNTs

Question 7

why do we use CNT functionalism?

Answer 7

1. increase the hydrophilicity to allow increase aqueous dispersion
2. stops aggregation of CNTs
3. allows further modifications by electrostatic and covalent bonds

Question 8

what is the difference between a covalent and non-covalent bond CNT?

Answer 8

covalent bonds- incorporated with the CNT structure
non-covalent bonds- coat the CNT

Question 9

what is the nanoneedle theory?

Answer 9

insertion of a functionalised hydrophobic nanotube into a membrane spontaneously (no energy needed)

parallel CNT into a perpendicular CNT

Question 10

what can SWNTs do?

Answer 10

enter the nucleus via nuclear pores

Question 11

how can CNTs be used?

Answer 11

1. radiolabelling
2. fluorescence intensity analysis

Question 12

what is radio labelling?

Answer 12

allows visualisation of CNT uptake for CT imaging

Question 13

how are CNTs removed from the body?

Answer 13

urinary excretion

Question 14

how are CNTs excreted from the kidney?

Answer 14

functionalised CNTs stop aggregation

aggregated non functionalised CNTs are too big = can’t fit the pores and cannot be excreted

Question 15

what type of CNTs are excreted faster?

Answer 15

highly functionalised CNTs

Question 16

how can CNTs be used in fluorescence intensity analysis?

Answer 16

by detecting the pi-pi interactions between chromophores and CNT surface= larger AUC

Question 17

what is MTX?

Answer 17

an antimetabolite and antifolaxe drug

competitively and reversibly inhibits the enzyme DHFR responsible for folic acid metabolism

Question 18

what does folic acid do?

Answer 18

synthesis of nucleoside thyme required for DNA synthesis and purine base synthesis

Question 19

what is a PK set back of MTX?

Answer 19

cellular resistance
low uptake
and therefore low efficacy

Question 20

explain the mechanism of CNT- MTX

Answer 20

1. CNT-MTX enters cell via nano needle hypothesis
2. no cell death as MTX cannot be released from the CNT

Question 21

how can we control the release of CNT-MTX?

Answer 21

addition of proteases/esterases

Question 22

why are CNT-MTX used?

Answer 22

The CNT in the hydrogel allows a slower and more controllable release behavior of MTX cellular uptake