Nanotoxicology Flashcards
why is nanoparticle size important for nanotoxicology?
diameter dependent excretion
e.g. zwitterionic cysteine coated quantum dots
e.g. PMAM-gold NPs accumulate in the blood = increase size
- larger size found in liver and spleen/ smaller size excreted in the urine
why is nanoparticle surface charge important for nanotoxicology?
increase conc of [DOPC:DOTAP:CHOL] in DOPC:DOTAP:CHOL:PEG liposomes
DOPC:DOTAP:CHOL = positive charge
charged liposomes = cleared quickly
what does DOPC:DOTAP:CHOL do to liposomes?
give it a/increase positive charge = aggregate with proteins in the blood = lung accumulation
where do DOPC:DOTAP:CHOL liposomes deliver drugs? why?
lung
due to protein aggregation due to their positive charge
how does PEG improve nanotoxicology?
mask surface charge = stop lung accumulation and fast excretion
= increasing the liposomes half life
why is nanoparticle shape important for nanotoxicology?
important for phagocytosis
pointed end of elliptical disc = fast phagocytosis (few minutes)
contact with flat region = slow phagocytosis (over 12hours)
why is it hard to use traditional toxicology assays for NPs?
e.g. CNTs - π–π stacking between CNT and reagents in the toxicology assays like MTT and LDH assay
π–π stacking with polycyclic nature/rings = blocks absorbance and fluorescent readings
what are traditional toxicology assays?
MTT - mitochondrial succinate dehydrogenase
LDH- lactate dehydrogenase
what reagents are used in traditional toxicology assays?
polycyclic nature/rings
how does LDH- lactate dehydrogenase work?
LDH releases when cells have defects in the membrane
= LDH detection
= toxicology reported
what is the toxic effect of NPs we are worried about?
biological side effects
environmental/workplace exposure of CNTs - lung and skin exposure
name NP affects
- NP inhalation
- brain - parkinson’s/alzheimer’s
- lung - asthma/bronchitis/emphysema/cancer
- circulatory - artherosclerosis/ vasoconstriction/ thrombus/ high bP
- heart - arrhythmia/ heart disease/ death
- lymphatic system - kaposi’s sarcoma
- skin - auto-immune diseases - NP ingestion
- GI - crohn’s disease/colon cancer
- orthopedic implants wear debris - auto-immune diseases/dermatitis/ urticaria/vasculitis
what type of NPs are less toxic?
chemically functionalised CNTs
what type of chemical functionalisations can you make to MWNTs?
- addition of alkyl chain - hydrophobic
- addition of ammonium chain - hydrophobic, increase dispersibility
how are inflammatory reactions notices with CNTs?
granuloma formation
- mass of immune cells that forms when the immune system attempts to eliminate substances
whats the difference between NT2 pristine and NT2 alykl/TEG?
NT2 alkyl and NT2 TEG had lower amounts of granulation than NT2 pristine
why does NT2 alkyl and NT2 TEG have lower amounts of granulation than NT2 pristine?
NT2 pristine- after sonication still forms long and hydrophobic needles
NT2 alkyl and NT2 TEG- after sonication forms smaller CNTs easier to be phagocytosed by the cell
how are CNTs degraded?
horseradish peroxidase (HRP) enzyme with low conc. hydrogen peroxide
myeloperoxidases (MPO)
what is horseradish peroxidase (HRP) enzyme with low conc. hydrogen peroxide be used for?
degrading CNTs - SWCNT and MWCNTs
what is myeloperoxidases (MPO) used for ?
CNT degradation
what is hMPO used for ?
implantable polymer degradation
