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BME 353 > Quiz 2: Metals and Alloys & Ceramics and Glasses/ Drug delivery > Flashcards

Quiz 2: Metals and Alloys & Ceramics and Glasses/ Drug delivery Flashcards

1
Q

Alloy

A

comprised of two or more elements, at least one is metallic

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2
Q

Ways metals mix

A

substitutional
interstitial

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3
Q

Solvent and solute in alloys

A

The more abundant element is referred to as the solvent, and the less abundant element is the solute.

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4
Q

Substitutional Alloys

A

one element replaces another at the original location

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5
Q

Conditions for substitutional solid solutions (alloys)

A

The atomic radii of the two elements similar (<=15%)
Their lattice types must be the same
The lower valency metal becomes the solvent

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6
Q

Crystalline architecture

A

Body-centered cubic: ductile, plastic, more workable
Face-centered cubic: ductile, plastic, workable
Hexagonal-close packed: lack plasticity

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7
Q

Substitutional Alloys examples

A

Dental alloys: Gold silver (crowns & bridges), silver copper (admixed dental amalgam), silver tin (low copper dental amalgam)
nickel-titanium (superelastic wires)

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8
Q

Interstitial Alloys

A

one element dispersed between, elements located in spaces between atoms in the unit cell
The solubility depends on the size of these gaps and the crystal structure.
important interstitial solute atoms: C, H, B, N, O
radii has to be <=59%

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9
Q

Alloys in use

A

permanently implantable: intended for indefinite use within the body (ex. stainless steels, cobalt-chromium-molybdenum, titanium)

biodegradable alloys: designed to be temporary, degrading, or bio-corroding over time (Mg)

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10
Q

Glass

A

inorganic product of fusion cooled to a rigid condition without crystallization, amorphous solid

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11
Q

Types of bio-ceramics- tissue interactions

A

morphological fixation
biological fixation
bioactive fixation

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12
Q

morphological fixation

A

dense, inert, nonporous ceramics attach to bone or tissue growth into surface irregularities by press fitting into a defect as a type of adhesive bond

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13
Q

biological fixation

A

porous inert ceramics attach by bone resulting from ingrowth into pores resulting in mechanical attachment of bone to material

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14
Q

bioactive fixation

A

dense, nonporous surface-reactive ceramics attach directly by chemical bonding with bond

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15
Q

Alumina and zirconia applications

A

Modular heads on femoral stem hip components, wear less than metal components

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16
Q

Calcium phophates

A

direct bond with bone tissue, biological apatites which constitute the principal inorganic phase in moral calcified tissues are carbonate hydroxyapatite

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17
Q

Calcium hydroxyapatite

A

(Ca10(PO4)6(OH)2)
Ca2+ ions surrounded by PO43- and OH- ions

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18
Q

Motivation for drug delivery system

A

provide stability and localization of drugs
enhance or enable drug efficacy (small molecule drugs, nucleic acids and proteins)

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19
Q

Challenges in drug delivery route across biological barrier

A

stability and permeability (change in pH, passing through mucus layer)

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20
Q

Drug release profiles

A

immediate release systems
first-order release systems: little bit of control in modulating drug release
zero-order release systems

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21
Q

Mechanisms of drug release

A

Diffusion
Degradation
Prodrug cleavage
Affinity-based release
Reservoir-based prolonged release
Degradation & dissolution-mediated release

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22
Q

DDss for drug targeting

A

Passive targeting: relies on physicochemical properties of the carrier (size, charge, shape), surface modification with poly(ethylene glycol) has shown to enhance circulation time and improve targeting

Active targeting: achieved through specific interactions by ligands on DDs

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23
Q

Microparticles (MPs)

A

provide extended duration of action, reduced systemic toxicity, and improved patient compliance
can be fabricated from natural or synthetic polymers
used in drug delivery, molecular imaging, and immune adjuvants
1 - 1000 um

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24
Q

Particle size

A

MPs tend to be depot formulations, taken orally, inhaled, or injected in tissue to achieve effects locally

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25
Q

Larger particle limitation

A

larger vehicles cannot be delivered directly into the circulation (eg. intravenously) bc of concerns over obstruction of blood vessels
more likely to clog needles or settle in a solution intended for injection
less likely to penetrate into cells than nanoparticles

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26
Q

MP preparation

A

1) single and double emulsion
2) coacervation phase separation

27
Q

Single and double emulsion

A

emulsification followed by solvent evaporation
D-F: double emulsion system (hydrophillic, protein drug)
F1: solvent evaporation, F2: extraction
A-C: single emulsion system (use if not soluble in water)
F1: solvent evaporation, F2: extraction

28
Q

Coacervation phase separation

A

Relies on the changes in solubility of polymers, leading to phase separation and micro-particle formation
relatively high loading efficiency, can be operated at low temp, suitable for sensitive drugs like insulin

29
Q

Coacervation phase separation example

A

Encapsulation of proteins into PLGA MP
PLGA dissolved in methylene chloride. aq solution of albumin dispersed in PGLA solution leading to formation of albumin droplets
polymer (silicone oil) with PLGA solution added to dispersion, causing formation of PLGA droplets and absorption onto surface of albumin droplets

30
Q

Nanoparticles

A

1-1000 nm
hold promise to revolutionize medical treatment with more potent, less toxic, and smart therapeutics

31
Q

Surface-to-volume ratio (apply to MP and NP)

A

smaller particles release drugs quicker, water penetrates particles more rapidly which accelerates drug release and degradation

32
Q

Polymeric NPs

A

formed by self assembly driven by hydrophobic interaction, generating hydrophobic core surrounded by a hydrophilic shell (polyermic micelles (20-200nm) nanospheres (100-200nm)

33
Q

Lipid-based NPs: Liposome

A

class of nano or micrometer sized phospholipid vesicles composed of one or multiple lipid bilayers that envelope the inner aqueous cores (where the drug is), 25nm-2.5um

34
Q

Lipid-based NPs: Solid lipid NPs (lipospheres)

A

consists of lipid matrix that remain in the solid state coated with a monolayer of phospholipid, 50-1000nm

35
Q

Lipid-based NPs: lipoplexes

A

cationic lipids can condense negatively charged nucleic acids at particular weight ratios to form nano complexes,

36
Q

Inorganic NPs: gold

A

for diagnosis and drug delivery
gold core is inert with low toxicity, monodispersed GNPs are easy to synthesize
1-150nm

37
Q

Inorganic NPs: magnetic NPs

A

for MRI contrast agents and nanocarriers for targeted drug delivery
Ex.iron oxide (Fe3O4)

38
Q

Bio-inspired NPs

A

Exosomes are inherent carriers of genetic and proteomic information and are believed to be a central form of cell-cell communication

39
Q

Bio-inspired NPs: protein NPs

A

amenable to surface modification due to abundant functional groups (carboxylic and amino groups) on NP surface
ex. gelatin, collagen, albumin, elastin

40
Q

Bio-inspired NPs: DNA nanostructures

A

designed by precise self-recognization of A-T and C-G pairings, can be degraded by DNase in tissues

41
Q

Hybrid NPs: cell membrane-coated NPs

A

synthetic nanoparticulate core cloaked with a layer of natural cell membrane, purpose is to have long circulation and disease-specific targeting
ex. red blood cells membrane coating prolongs the blood circulation of NPs, white blood cells membrane coating enable site-specific targeting of the vasculature of tumors or inflammatory tissues

42
Q

Gene therapy

A

Biomaterial used needs to have a positive charge (nucleic acids are negative)

43
Q

Polycations for construction of gene delivery NPs

A

PLL, chitosan, PBAE, DMAEMA, Dendrimer (PAMAM), beta-cyclodextrin-containing polycation, PEI

44
Q

Cell-penetrating peptides for gene delivery

A

Adopt an inherent helical structure or form a helix during membrane penetration which strengthens the interactions with cell membranes to facilitate cellular internalization

45
Q

Which of the following is an application for metal biomaterials?
Bone and joint replacement
Dental Implants
Intravascular stents
All of the above

A

All of the above

46
Q

True or false: Any combination of elements can form a substitutional alloy as long as one is a metal

A

False

47
Q

Which of the following is false regarding interstitial alloys?
The solute atoms should be <=59% of the solvent atoms’ atomic radius
Common interstitial solute atoms include gold, platinum and mercury
Solute atoms are located in spaces between atoms in the unit cell
Steel (iron and carbon) is an example of an interstitial alloy

A

Common interstitial solute atoms include gold, platinum and mercury

48
Q

Which of the following alloys would be most suitable for a biodegradable stent?
Stainless steel
Colbalt-Chromium-Molybdenum alloy
Magnesium alloys
Titanium alloys

A

Magnesium alloys

49
Q

What is not an advantage of ceramics?
High wear resistance
High modulus
Bioactive in the body
High fatigue resistance

A

High fatigue resistance

50
Q

True or false: alumina and zirconia are the two most commonly used structural bioceramics.

A

True

51
Q

What is the primary structural component of bones?
Hydroxyapatite
Tricalcium phosphate
Octacalcium phosphate
Zirconia

A

Hydroxyapatite

52
Q

True or false: Interatomic bonding in ceramics is either ionic or covalent

A

True

53
Q

What is not an application of ceramics?
Bone, plates, screws
Orthodontics
Dental restorations
None of the above

A

None of the above

54
Q

Which of the following is an advantage of using nanoparticles in drug delivery?
Increased drug stability
Reduced drug solubility
Increased clearance from immune system
Faster degradation in the body

A

Increased drug stability

55
Q

Which material is commonly used for constructing biodegradable microparticles for drug delivery?
Gold
Poly(lactic-co-glycolic acid) (PLGA)
Silver
Silicon dioxide

A

Poly(lactic-co-glycolic acid) (PLGA)

56
Q

What is the primary reason PEGylation (adding PEG) of nanoparticles?
To increase drug degradation
To reduce drug absorption
To increase circulation time by evading immune clearance
To improve the particle’s magnetic properties

A

To increase circulation time by evading immune clearance

57
Q

Which of the following best describes the term “targeted drug delivery”?
Delivering drugs at a constant rate throughout the body
Delivering drugs specifically to a disease tissue or organ
Delivering drugs uniformly across all tissues
Delivering drugs based on body temperature

A

Delivering drugs specifically to a disease tissue or organ

58
Q

In a swelling-controlled release system, what triggers the release of the drug?
Erosion of the outer layer
Absorption of water into the matrix causing it to expand
Diffusion through a membrane
Degradation of the drug molecules by enzymes

A

Absorption of water into the matrix causing it to expand

59
Q

Which of the following is a common route of administration for nanoparticle-based drug delivery systems?
Intravenous injection
Oral ingestion only
Inhalation only
Topical application only

A

Intravenous injection

60
Q

Microparticles are generally used in drug delivery systems for what purpose?
To provide immediate drug release
To enhance long-term, controlled release of the drug
To limit drug exposure to specific parts of the body
To increase the drug’s molecular weight

A

To enhance long-term, controlled release of the drug

61
Q

True or false: nanoparticles in drug delivery systems can improve the solubility of hydrophobic drugs.

A

True

62
Q

True or false: microparticles are preferred for drug delivery because their larger size helps them cross the blood-brain barrier

A

false

63
Q

True or false: nanoparticles’ higher surface area-to-volume ratio enables more efficient drug loading and release than microparticles

A

True

64
Q

add the quiz

A

BME 353 (12 decks)

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