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Food Analysis > Lecture 17 - Nanomaterials > Flashcards

Lecture 17 - Nanomaterials Flashcards

1
Q

what is nanotechnology?

A

manipulation of matter at the nanoscale to generate size dependent functionalities different from atom/molecules/bulk materials

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2
Q

what is a nanomaterial?

A

material with at least one of its dimensions is between 1-100nm

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3
Q

what makes nanomaterials unique?

A
  • more molecules/atoms on surface
  • increased surface area
  • dominance of quantum effects
  • different crack propagation
  • higher elastic modulus
  • altered electrical, optical and magnetic properties
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4
Q

what is the size of bulk materials?

A

> 1000nm

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5
Q

compare the hardness, strength and wear resistance of nano materials to bulk materials

A

hardness: 5 times higher
strength: 3-10 times increased
wear resistance: 170 times increased

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6
Q

compare wear resistance of nano to bulk materials

A

bulk is reduced half of nano

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7
Q

what is QD?

A

quantum dots

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8
Q

what are the food applications of QD?

A
  • rapid detection of food borne pathogens

- imaging of gluten networks

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9
Q

what determines the vascular movement of nanoparticles

A

hydrodynamics of particles are determined by their size and shape

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10
Q

describe the protein binding of nanoparticles

A

nanoparticles interact with proteins to form bio-corona

determined by availability and affinity of the protein and the material chemistry

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11
Q

how do nanoparticles circulate through the body?

A

through the lymphatic system

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12
Q

how are nutrients and compounds absorbed in the intestine

A
  1. active transport through specific channels on the surface of epithelial cells
  2. passive transport via diffusion
  3. paracellular transport
  4. transport via M cells
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13
Q

how is bioavailability and absorption of nutrients enhanced by nanotechnology?

A
  1. paracellular transport
  2. endocytosis of nanoparticles
  3. better delivery of nutrient and drug encapsulated in nanoparticle
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14
Q

iron from nanocompounds containing iron and zinc is highly bioavailabile in ____ without tissue accumulation

A

rats

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15
Q

what is the use of zein nanoparticles coated with carboxymethyl chitosan?

A

encapsulation and controlled release of vit D3

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16
Q

what are applications of nanotechnology throughout the food chain?

A
  1. fertilizer, pesticide, drug delivery, infection control
  2. intelligent packing (antimicrobial, gas permeability)
  3. tracking RFID with sensor
  4. food contact materials
  5. flavour enhancement (fortification)
17
Q

how many nanomaterial particles are ingested in humans?

A

10^12-14 inorganic particles

18
Q

what happens do nanomaterials in foods in post ingestion?

A
  1. digestion through mucus layer
  2. contact with enterocytes and/or M cells
  3. uptake via cellular entry or paracellular transport
19
Q

what is the most common mechanism for uptake of NP into intestinal epithelial cells

A

endocytosis

20
Q

size influences____?

what is this shown by?

A

absorption

shown by greater absorption of smaller polystrene particles compared to larger particles

21
Q

as the size of nanoparticle increases, what changes?

A

properties (eg. color)

22
Q

nanomaterials behave differently in….

A

biological systems

23
Q

what are potential implications of nanotechnology to human and environmental health?

A
  1. redox activity and ROS
  2. dissolution, shedding toxic ions
  3. cationic toxicity
  4. lung fibrosis
  5. inflammasome actiation
  6. photoactivation
  7. embryo hatching interference
  8. membrane lysis
24
Q

describe the protocol for detection and quantification of NMs in food

A
  1. hazard indentification
  2. exposure assessment and dose response assessment
  3. risk characterization
  4. risk management
25
Q

what are challenges for the detection and quantification of engineered nanomaterials (ENMs) in food?

A
  1. identification of the physical or ionic form
  2. quantification of the NM
  3. interference from matrix and naturally occurring nanomaterials
  4. possible transformations of ENMs in food matrix and during sample prep
  5. potential variations originating from different surfaces
26
Q

describe the challenge of the identification of NMs

A

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

27
Q

why is it challenging to quantify NMs?

A

because extremely low concentrations of NMs needs instruments with high sensitivity

28
Q

what is the protocol for detection and quantification of NMs in food?

A
  1. sampling
  2. sample prep: matrix degradation or NMs extraction
  3. purification and concentration
  4. detection, quantification and characterization
29
Q

What is the protocol for quantification of silica particles in food?

A
  1. weight sample
  2. add concentrated nitric acid
  3. microwave digestion
  4. cool down to room temp
  5. dilute further with water
  6. quantify amount of SiO2 using ICP-MS or ICP-OES

Food Analysis (17 decks)

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