Lecture 17 - Nanomaterials Flashcards
what is nanotechnology?
manipulation of matter at the nanoscale to generate size dependent functionalities different from atom/molecules/bulk materials
what is a nanomaterial?
material with at least one of its dimensions is between 1-100nm
what makes nanomaterials unique?
- more molecules/atoms on surface
- increased surface area
- dominance of quantum effects
- different crack propagation
- higher elastic modulus
- altered electrical, optical and magnetic properties
what is the size of bulk materials?
> 1000nm
compare the hardness, strength and wear resistance of nano materials to bulk materials
hardness: 5 times higher
strength: 3-10 times increased
wear resistance: 170 times increased
compare wear resistance of nano to bulk materials
bulk is reduced half of nano
what is QD?
quantum dots
what are the food applications of QD?
- rapid detection of food borne pathogens
- imaging of gluten networks
what determines the vascular movement of nanoparticles
hydrodynamics of particles are determined by their size and shape
describe the protein binding of nanoparticles
nanoparticles interact with proteins to form bio-corona
determined by availability and affinity of the protein and the material chemistry
how do nanoparticles circulate through the body?
through the lymphatic system
how are nutrients and compounds absorbed in the intestine
- active transport through specific channels on the surface of epithelial cells
- passive transport via diffusion
- paracellular transport
- transport via M cells
how is bioavailability and absorption of nutrients enhanced by nanotechnology?
- paracellular transport
- endocytosis of nanoparticles
- better delivery of nutrient and drug encapsulated in nanoparticle
iron from nanocompounds containing iron and zinc is highly bioavailabile in ____ without tissue accumulation
rats
what is the use of zein nanoparticles coated with carboxymethyl chitosan?
encapsulation and controlled release of vit D3
what are applications of nanotechnology throughout the food chain?
- fertilizer, pesticide, drug delivery, infection control
- intelligent packing (antimicrobial, gas permeability)
- tracking RFID with sensor
- food contact materials
- flavour enhancement (fortification)
how many nanomaterial particles are ingested in humans?
10^12-14 inorganic particles
what happens do nanomaterials in foods in post ingestion?
- digestion through mucus layer
- contact with enterocytes and/or M cells
- uptake via cellular entry or paracellular transport
what is the most common mechanism for uptake of NP into intestinal epithelial cells
endocytosis
size influences____?
what is this shown by?
absorption
shown by greater absorption of smaller polystrene particles compared to larger particles
as the size of nanoparticle increases, what changes?
properties (eg. color)
nanomaterials behave differently in….
biological systems
what are potential implications of nanotechnology to human and environmental health?
- redox activity and ROS
- dissolution, shedding toxic ions
- cationic toxicity
- lung fibrosis
- inflammasome actiation
- photoactivation
- embryo hatching interference
- membrane lysis
describe the protocol for detection and quantification of NMs in food
- hazard indentification
- exposure assessment and dose response assessment
- risk characterization
- risk management
what are challenges for the detection and quantification of engineered nanomaterials (ENMs) in food?
- identification of the physical or ionic form
- quantification of the NM
- interference from matrix and naturally occurring nanomaterials
- possible transformations of ENMs in food matrix and during sample prep
- potential variations originating from different surfaces
describe the challenge of the identification of NMs
unlike other consistuents of food (eg fiber or protein), the identity of NMs is defined by size and chemistry
thus, these two parameters need to be detected together
why is it challenging to quantify NMs?
because extremely low concentrations of NMs needs instruments with high sensitivity
what is the protocol for detection and quantification of NMs in food?
- sampling
- sample prep: matrix degradation or NMs extraction
- purification and concentration
- detection, quantification and characterization
What is the protocol for quantification of silica particles in food?
- weight sample
- add concentrated nitric acid
- microwave digestion
- cool down to room temp
- dilute further with water
- quantify amount of SiO2 using ICP-MS or ICP-OES
