Nanoparticles Flashcards
name methods of nanoparticles in imaging
2-deoxy-2-(18F)fluoro-D-glucose [FDG] for positron emission tomography [PET]
Iodinated small molecules for Computer Tomography (CT)
Chelated gadolinium for Magnetic Resonance Imaging (MRI)
what are nanoparticles disadvantages in imaging?
low signal intensity
poor stability
nonspecific interactions
rapid clearance
= fewer cells imaged at a time
how do PET scans work?
Detects pairs of gamma rays emitted indirectly by
a positron- emitting radionuclide
when are PET scans used?
detecting cancer metastasis
how do CT scans work?
computer generation of multiple X-RAY images from multiple angles to produce cross-sectional (tomographic) images
when are CT scans used?
CT colonoscopy = high risk of colon cancer
full-motion heart scans = risk of heart disease
how do MRI scans work?
strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body
when are MRI scans used?
staging rectal/prostate cancer
why do we use nanoparticles in imaging?
- high avidity as they can be coated with multiple ligands
- allow multiple bond interactions
- = nanoparticle accumulation at tumour site
- = increase signal-to-noise ratio
- longer circluation
- repeated imaging
why do we use nanoparticles in diagnostics?
- Nanoparticles can lead to improved solubility of cargo, especially of large molecules (such as mRNA, siRNA, antibodies or other protein drugs) which may be hydrophobic.
- Nanoparticles provide an outer layer of functionalization, which helps improve the stability and protects these molecules from enzymatic, pH or other environmental factors which may cause premature degradation prior to them reaching the target disease site in the body.
how do pregnancy test work?
test detects human chorionic gonadotropin (hCG)
hormone excreted in urine
when are gold NP’s used?
diagnostic
testing for pregnancy
attached with monoclonal antibody for hCG
once attach n travelled = strip activated
what are SPIONS
Small nanomaterials consisting of iron oxide core crystals surrounded by a stabilising polymer or polysaccharide shell
2 most commonly studied iron oxides have been
magnetite (Fe2O4) and maghemite (g-Fe2O3)
MRI contrast agents used in the clinic
what are MRI contrast agents?
contrast media used to improve the visibility of internal body structure in magnetic resonance imaging (MRI)
what is the most common MRI contrast agents?
gadolinium-based OMNISCAN
what drug classification are MRI contrast agents known as?
T1 or T2 agents
what is a disadvantage of SPIONs?
phagocytosis by macrophages = detection of macrophage infiltration
how can detection of macrophage infiltration be useful?
SPIONs used as MRI contrast agents can be used to detect inflammation and infection therefore help used to detect severe arthritis and osteomyelitis
- inflammation of bone/bone marrow
what is SPECT/CT?
single photon emission computed tomography
non invasive nuclear imaging test
fused scan can provide more precise information about how different parts of the body function and more clearly identify problems such as tumours (lumps) or Alzheimer’s disease.
what can SPECT/CT be used for?
identifying tumours (lumps) and alzheimer’s disease
what is administered in SPECT/CT?
MWNT-DPTA[111In]
IV
what are quantum dots?
Tiny particles or nanocrystals of a semiconducting material with diameters in the range of 2-10 nanometers
name examples of quantum dots?
cadmium selenide
fluorescent NPs
cadmium selenide PK effects
toxic
how does size effect fluorescent quantum dots?
smaller dots = blue
larger dots = red
what are quantum dots used for?
cancer diagnosis
sentinel lymph nodes (SLN) mapping
what are sentinel lymph nodes (SLN)?
first lymph node to which cancer cells are most likely to spread from a primary tumour
- there can be more than one
how are sentinel lymph nodes (SLN) detected?
using near-infrared (NIR) fluorescent quantum dots
what do near-infrared (NIR) fluorescent quantum dots do?
near-infrared (NIR) fluorescent imaging = fine details of lymphatic flow from the injection site to the SLN
what is multispectral optoacoustic tomography (MSOT)?
whole body imagine of biochemical markers in small animals
how does multispectral optoacoustic tomography (MSOT) work?
Detects the acoustic waves generated by the thermoelastic expansion of the absorbing molecules of the surrounding environment.
what are acoustic waves ? and when are they used?
longitudinal waves
for MSOT
what are properties of gold NPs?
Due to plasmon resonance, gold nanoparticles
exhibit strong optoacoustic responses
long retention times in tissues
current standard for signal generation in optoacoustic imaging
Excellent signal strength and photo-stability
what is indocyanine green (ICG)?
used in medical diagnostics
determining cardiac output, hepatic function and liver blood flow and for ophthalmic angiography
how does indocyanine green (ICG) work?
infrared frequencies penetrate retinal layers, allowing ICG angiography to image deeper patterns of circulation
ICG binds tightly to plasma proteins and becomes confined to the vascular system
short half life
how are ICG administered?
encapsulated in a liposome
what is the advantage of encapsulating ICG? and what in?
- Enhances the stability of ICG, addressing its limitations in terms of rapid elimination and poor stability in aqueous media
- Demonstrates improved physicochemical attributes, bioavailability, and pharmacokinetic characteristics, reducing degradation risks .
what is indocyanine green (ICG)?
optoacoustic agents
what are theranostic applications?
therapeutic agent + diagnosing
name a theranostic agent
Arginylglycylaspartic acid (RGD)
what is Arginylglycylaspartic acid (RGD)?
a theranostic agent
tripeptide composed of L- arginine, glycine and L-aspartic acid
