exam 3- nanodermatology

Question 1

___ is a major storage protein from corn (what size?)

Answer 1

zein
19-22 kDa

Question 2

zein is a ___ and ___ protein; depending on conditions, it can form ___, ___, ___, or ___

Answer 2

versatile and biocompatible

nanofibers, films, stripes, or discs

Question 3

what are zein-based nanofibers used for?

Answer 3

to build tissue scaffolding (films) utilizing micropatterning techniques (applied in skin regeneration)

Question 4

proposed 3D structural models of zein

Answer 4

cylindrical model
ribbon-like model (22 kDa)
hairpin model (19 kDa)
super helical structural model

Question 5

zein based micro and nano particles, how the models build on each other

Answer 5

cylindrical model: alpha helices transform to beta sheets –> sheets form long ribbons –> curling –> collapse of toroid hole –> sphere growing

Question 6

oral administration of a drug: poor drug ___ or enzymatic ___ in the ___ or ___

what’s alternative?

Answer 6

absorption
degradation
GI tract or liver

hypodermic needle

Question 7

whats a more appealing option compared to oral administration?

Answer 7

using a skin patch
- however, transdermal delivery is severely limited by skins’ outer stratum corneum layer (~ 1000 nm)

Question 8

there has been a long-standing belief that stratum corneum consisted exclusively of ___, devoid of…

Answer 8

dead cells
biological activity and function

Question 9

the stratum corneum performs protective and adaptive physiological functions…

Answer 9

mechanical shear, impact resistance, water flux, and hydration regulation, microbial proliferation

Question 10

an alternative to patches and traditional needles is ___ …they permit transport of ___, as well as possibly ___ and ___

Answer 10

arrays of microscopic needles

macromolecules, supramolecular complexes, and microparticles

Question 11

despite micro-needles very large size relative to drug dimensions…

Answer 11

on a clinical length scale, they remain small

Question 12

3 transdermal drug deliveries using micro-needles

Answer 12

1- “poke with patch” - used for insulin delivery in diabetic hairless rats (a solution of insulin placed on top of microneedle array for 4 hr)

2- “coat and poke” - used for protein vaccine delivery (microneedles were prepared with a dry film coating of antigen and then inserted into the skin of hairless guinea) - future for allergy treatments?

3- “dip and scrape” - arrays were dipped into solution containing therapeutic drug and scraped multiple times across skin of mice to create microabrasions

Question 13

nano-needles may be too small to penetrate the ___ but can allow to perform ___ on ___ at ___

Answer 13

stratum corneum
surgical operations on living cells at nanoscale resolution

Question 14

the nanoneedle example: they have 4 modified ___ tips using a ion beam etching- the tips were sharpened to ultrathin needles of ____ nm in diameter

results indicated that the needles penetrated the cell membrane following indentation to a depth of __

Answer 14

AFM
200-300 nm

1-2 um

Question 15

potential applications of nanoneedles

Answer 15

• drug delivery without NPs
• manipulation of organelles