Magnetic nano applications in biomedicine

Question 1

Give five applications of magnetic nanoparticles

Answer 1

1)contrast agents for MRI 2) magnetic heating of nanoparticles during therapy (hyperthermia) 3) tissue engineering/repair 4) drug delivery 5) magnetofection (magnetically assisted gene transfection)

Question 2

Is MRI safe?

Answer 2

hells yeah ,the safest imaging technique

Question 3

Why are contrast agents required in MRI?

Answer 3

To increase the ability to distinguish between differences in soft tissues

Question 4

What is magnetic hyperthermia?

Answer 4

An experimental tool in cancer therapy, uses mag nans to raise local temp in tumour which deactivates normal cellular processes (thermal ablation) resulting in necrosis. It increases therapeutic affects of other treatments. The surface of the nans can bechemically modified to enable target to a specific tissue eg with tumour specific antibodies

Question 5

What is thermal ablation?

Answer 5

Deactivating normal cellular processes with a locally raised temperature

Question 6

How are mag nans used to deliver drugs/genes?

Answer 6

It is for localisation of nans/drug at target site, prolonged drug release and targeting to specific cell receptors. Also magnetofection which is when magnetic particles associated w/vector DNA are transfected into cells by the influence of an external mag field

Question 7

What is magnetofection?

Answer 7

When mag particles associated w/vector DNA are transfected into cells by the influence of an external mag field

Question 8

Why do we need nanoscale superparamagnetic particles?

Answer 8

Because they need to be small enough for administration, must reside in vivo long enough to reach the target/avoid immunological reactions/toxicity/rapid excretion and capture by undesired tissues. The smaller/more neutral/more hydrophillic the particle surface, the longer its plasma 1/2 life - the particles are attracted to a a magnetic field but no remanence, and do not agglomerate after the removal of the field.

Question 9

What increases a particles plasma 1/2 life?

Answer 9

Being smaller, neutral and hydrophillic

Question 10

What 2 points must we consider when making/using mag nans?

Answer 10

Transport across physiological barriers (bbb, vascular capilliary endo, cell membranes) and they must be uniform in size/small enough/large magnetic susc/high colloidal stability/low toxicity and high biocompatibility

Question 11

What is colloidal?

Answer 11

dispersed within a continuous medium in a manner that prevents them from being filtered easily or settled rapidly.

Question 12

What 2 common stages do synthesis protocols have in common?

Answer 12

1) a short nucleation step 2) slower growth processes on the existing nuclei

Question 13

Why do we use iron oxides?

Answer 13

They have useful magnetic properties and are potentially less toxic than metallic and they are easy to functionalise particle surfaces

Question 14

What is SPIONS?

Answer 14

Superparamagnetic iron oxide nanoparticles

Question 15

What are superparamagnetic iron oxide nans?

Answer 15

SPIONS

Question 16

What is the main purpose of surface treatment of nans?

Answer 16

To prevent agglomeration and to generate multifunction

Question 17

What are first gen nanoparticles?

Answer 17

Pure nanoparticles, Fe2O3 Fe304

Question 18

What are 2nd gen nans?

Answer 18

Chem mod eg SiO2 coated Fe3O4

Question 19

What are advanced gen nans?

Answer 19

further mods to functionalise eg ligand coated SiO2-Fe3O4 particles

Question 20

How do we prevent nan agglomeration?

Answer 20

Environmental conditions affecting the stability of nan suspensions

Question 21

How do we functionalise the particles?

Answer 21

1)chemically active nans can b coated w/bioactive components such as ligands and abs using knowledge of surface chem of the particle 2) these partcles can b trapped in nanobeads such as liposomes or biodegradable polymers which already have active components