Ch2 Flashcards
What is a biomarker
a biomolecule that has the ability to play a prime role in different biological and pathological processes or give a specific pharmacological response to a drug
it is a short-term biological marker that can be used as an indicator of a particular disease stage or some other physiological states of an organism.
What are the 3 types of biomarkers
predictive - help predict therapeutic response to a specific drug
prognostic - indicate the development of a disease
diagnostic - detects or confirms the presence of a disease or condition of interest, or identifies an individual with a subtype of the disease
Types of Molecular biomarkers?
- Macromolecules: DNA/RNA, proteins
- wide applications in cancer and viral diseases
- ex. receptor proteins on normal cells turn into cancer biomarkers - Small molecules: products in metabolic pathways which may regulate biological processes
- ex. cortisol used as stress biomarker
- continuous monitoring useful for early warning for patients with critical conditions such as kidney, liver or heart disease
What body fluids are used as a source for biomarkers?
blood (gold standard), urine, pleural effusion, sweat, cerebrospinal fluid, saliva
define transcellular and paracellular, and which fluids receive biomarkers through these methods?
transcellular: diffusion through the plasma membrane of capillary endothelial cells or vesicular transport through the cell (transcytosis)
paracellular: diffusion or advective transport through the space between cells
this is for interstitial fluid, swear and saliva
examples of using sweat for diagnostics
limited commercial application, for infant cystic fibrosis, detects chloride concentrations in the sweat
consists of water and electrolytes
Examples of saliva for diagnostics
detection of viral diseases, gastric ulcers and cancer, liver disease and tuberculosis
monitor levels of polypeptides, steroids, antibodies, alcohol, and various drugs
growth factors, plays an important role in wound healing and oral health
Examples of urine for diagnostics
monitor body homeostasis and some metabolic disease processes
citrate levels are related to several diseases, including kidney dysfunction and prostate cancer
examples of CSF
source of brain derived proteins -> neurodegenerative disorders such as alzheimers and parkinsons
- molecular abrations in AD brain are reflected in cerebrospinal fluid.
What is lysing
the release of biomarkers from the extracellular vesicles, through mechanical, thermal, or chemical disruption
What are some pretreatment procedures for analysis of molecular biomarkers
lysing
purification and target isolation
what are the three main groups of biomolecular detection assays
- biocatalytic assays
- affinity-based assays
- nucleic acid hybridization-based assays
biomolecular detection assays can be used to detect biomarkers indicative of what 3 conditions?
- infectious diseases
- chronic/organ-related diseases
- cancers
which assays are typically used for infectious disease detection?
affinity based and nucleic acid hybridization based
which assays are typically used for chronic diseases?
affinity based and biocatalytic
which assays are typically used for cancer?
affinity based and hybdridization
How do biocatalytic assays work?
reaction of target analyte with recognition element such as enzymes, whole cells, etc, resulting in detectable outcome
Explain how glucose detection via glucose oxidase works
oxidation of glucose (target analyte) in the presence of glucose oxidase
O2 and H20 form gluconic acid and hydrogen peroxide
the H2O2 is electrochemically oxidized at the anode of the EC probe, producing a current proportional to the concentration of glucose in the sample
explain how cholesterol detection via cholesterol oxidase works
paper based test
consists of cerium oxide NPs
cholesterol oxidase catalyzes oxidation of cholesterol, produces H2O2, forming peroxide complex on the nanoceria surface
induces colour change from white to yellow/orange, quantified by image J on smartphone
Explain how uric acid detection works
in the presence of O2, uricase enzyme catalyzes uric acid to produce H2O2.
molybdenum disulfide (MoS2) is also under catalysis, and
ok what on earth is this explanation ma’am (slide 22)
How do affinity based assays work?
employ non-reactive approach, in which specific binding interaction between analyte and BRE is converted to a measurable signal by a transducer
Why would affinity based assay be used over biocatalytic?
there is a lack of sufficiently selective enzymes for certain analytes. In this case, we would use affinity-based
Types of BREs for affinity based assays
antibody based
aptamber based
MIP (molecularly imprinted polymers)
what is an antibody :)
uniquely patterned amino acids that can only bind to target antigens with a specific molecular sequence that provides complementary charges and noncovalent bonds
monoclonal and polyclonal, created by lymphocytes
how are antibodies created
- inject animal with specific antigen
- animals immune system will produce specific antibodies
- harvested as whole serum
- typically polyclonal, most antigens are complex structures with multiple epitopes, they result in the production of multiple anitboies
why are mABs used over pABs?
mABs are produced in vitro using tissue culture techniques, and are used in cases where all of the antibodies must bind with high affinity to a single epitope
