Lecture 1

Question 1

Why Biosensors?

Answer 1

1. Advances in biosensing technologies have coincided with increased life expectancy and substantial improvements in the treatment and management of diseases, especially those associated with aging.
2. Using biosensors for early diagnosis of diseases, like cancer, leads to significantly better clinical outcomes for patients and lower economic burdens
3. Using biosensors for monitoring (as in the case of Type I diabetes), especially outside the clinic, leads to better quality of life, less demand on acute healthcare, and lower likelihood of complications.

Question 2

What challenges Biosensors face?

Answer 2

achieving greater analytical performance, simplicity, and cost-effectiveness of clinical biosensors with the ultimate aim of providing point-of-care testing.

Question 3

How many classes of material in biosensor are there? what are they?

Answer 3

5. Hydrogels, nano materials, stimuli-responsive materials, polymers, fibrous materials

Question 4

Explain two ways of creating hydrogel materials for biosensors?

Answer 4

Creating physical crosslinks between molecule by:
1) hydrogen bondings between O-H
2) adding calcium

Question 5

What are some examples of nano materials used in biosensors?

Answer 5

1. Carbon dots
2. Ultra small MXene
3. quantum dots
4. metal nanostructures
5. poulymers NPs

Question 6

What are some examples of triggers for stimule-responsive materials used in biosensors?

Answer 6

1. Heat
2. frequency?

Question 7

Explain two ways of creating polymeric materials for biosensors?

Answer 7

1. exposing hydrophilic polymers to irradiation
2. radical polymerization of hydrophilic monomers through multifunctional cross linkers.

Question 8

What are some examples of Fibrous materials used in biosensors?

Answer 8

1. Nitrocellulose
2. glass fiber
3. silk

Question 9

What are biosensors?

Answer 9

Biosensorsare (1) analytical tools or devices that (2) measure biological or chemical reactions and (3) generate signals proportional to the concentration of atarget analyteor biomarker in a sample.

Question 10

What are the types of biosensors?

Answer 10

(1) research-based biosensors
(2) point of care (POC)

Question 11

What is a biomarker?

Answer 11

(1) a biological characteristic that is (2) objectively measured and evaluated as (3) an indicator of normal biological processes, pathogenic processes, or pharmacological response to a therapeutic intervention.”

Question 12

What are the types of biomarkers?

Answer 12

(1) Nucleic acids: DNA (SNPs, mutations) & RNA (mRNA, uRNA, etc)
(2) proteins: prostate-specific antigen & enzymes
(3) others: exosomes, cells, hormones

Question 13

What are the 4 clinical classifications of biomarkers?

Answer 13

based on clinical role:
(1) diagnostic
(2) prognostic
(3) predictive
(4) monitoring

Question 14

What type of biomarkers answer the following: “ Who has the disease and what is its type or grade?”

Answer 14

Diagnostic biomarkers

Question 15

Explain diagnostic biomarkers (uses and specificity)

Answer 15

(1) used to detect the presence of disease or to identify disease subtypes.
(2) can be present at any stage during disease development
(3) may be specific to various factors such as disease stage, tissue type, and patient age
(4) Diagnostic tests may also be based on a set of biomarkers

Question 16

a 20-gene assay is used to classify patients with diffuse large B-cell lymphoma into subgroups of different tumor cell-of-origin signatures. What type of biomarker is this?

Answer 16

Diagnostic biomarker

Question 17

Human Papillomavirus (HPV) is used to detect uterine and cervical cancers, as it is found in over 90% of cancer lesions. What type of biomarker is this?

Answer 17

Diagnostic biomarker

Question 18

What type of biomarkers answer the following: “ What is the most likely clinical outcome without therapy”

Answer 18

Prognostic biomarkers

Question 19

Explain Prognostic biomarkers (uses)

Answer 19

(1) can predict the probable course of disease including the likelihood of a clinical event like death, disease progression, or reoccurrence
(2) influence the aggressiveness and type of therapy administered

Question 20

Give examples on prognostic biomarkers.

Answer 20

(1) traditional: assessment of clfinicopathologic characteristics like tumor size, number of positive lymph nodes (with tumor cells), and evidence of metastasis.

(2) molecular indicators: BRCA 1 and BRCA2 for breast cancer, TP53 gene for leukemia

Question 21

BRCA1 and BRCA2 gene mutations are used to assess the likelihood of developing a contralateral breast cancer after diagnosis with a primary breast cancer. What type of biomarker is this?

Answer 21

Prognostic biomarkers for breast cancer,P

Question 22

TP53 gene mutation, used to assess likelihood of death in patients with chronic lymphocytic leukemia. What type of biomarker is this?

Answer 22

Prognostic biomarker.

Question 23

What type of biomarkers answer the following: “What is the most effective therapy?”

Answer 23

Predictive (response) biomarker

Question 24

Explain predictive (response) biomarker

Answer 24

used to predict the effect of administering a therapy, aiding clinicians in selecting the most effective treatment for a patient

Question 25

Her2/Neu (HER2) protein is guides clinicians to administer hercaptin for patients with over-expression of this gene and tamoxifen for other patients. What type of biomarker is HER2?

Answer 25

Predictive (Response) Biomarkers

Question 26

The presence of specific mutations in the epidermal growth factor receptor (EGFR) gene is used to predict whether to administrate erlotinib or gefitinib for lung cancer therapy. What type of biomarker is EGFR.

Answer 26

Predictive (Response) Biomarkers

Question 27

What type of biomarkers answer the following: "Is the therapy effective and will the disease reoccur?"

Answer 27

Monitoring Biomarkers

Question 28

Explain Monitoring Biomarkers

Answer 28

(1) used to evaluated serially over time to investigate the state or extent of a disease, or the effect of a therapeutic drug or treatment. (2) The time-dependent nature of this measurement focuses on change in a biomarker’s levels as a sign of a patient’s current or future medical condition; (2) thus, the measurement must be interpreted as relative to normal changes in the biomarker values due to physiological and temporal fluctuations

Question 29

cancer antigen 125 (CA-125) is used to assess the status of ovarian cancer or the response to treatment. What type of biomarkers is CA-125?

Answer 29

Monitoring Biomarkers

Question 30

Can one biomarker fall into more than one category?

Answer 30

Yes. For example Prostate specific antigen (PSA) is used to screen for prostate cancer (PC) (diagnostic), assessment of PC status and/or burden (monitoring), and the likelihood of progression (prognostic)

Question 31

How does biosensing happen?

Answer 31

(1) A sample is collected, (2) the analyte is extracted containing the target biomarker and potentially impurities. (3) The target will interact with the bioreceptor immobilized on a substrate. (4) the affinity interaction is transduced into a measurable signal, which can be optical, mass based, or electrochemical.

Question 32

What are the main components of biosensors?

Answer 32

(1) sensning/recognition element (bioreceptor) (2) transducing element (3) signal processor (reader)

Question 33

What is the role of bioreceptors in biosensing?

Answer 33

Capturing or binding to targets (biomarkers)

Question 34

What is the role of the transducing elemnet in biosensing?

Answer 34

converts analyte-receptor recognition event into measurable signal

Question 35

What is the role of the signal processor or reader in biosensing?

Answer 35

interprets the emitted signal and outputs a quantifiable result. 

Question 36

What are the criteria for Bioreceptors?

Answer 36

Depending on target biomarker. Ideally, this element should bind the target biomarker with both high affinity and high specificity.

Question 37

Give an example for bioreceptors.

Answer 37

(1) Antibodies are most commonly used for sensing biomarkers belonging to the families of proteins, viruses, or cells. (2) Oligonucleotides such as DNA or RNA strands or oligonucleotide analogs such as peptide nucleic acids (PNA) are typically used for sensing of nucleic acid biomarkers.

Question 38

What is a transducer?

Answer 38

key element that helps convert the measured signal and dictates the type of detector that will be required based on the nature of the output signal generated. For each type of output signal, various detection platforms can be selected depending on the sensor’s intended use and purpose.

Question 39

What are the different modes of detection (readouts)

Answer 39

(1) piezoelectric -> changes in mas (2) electro-mechanical -> change in electric distribution. (3) optical -> change in light intensity (4) calorimetric -> change in heat

Question 40

What is the most common type of optical readout?

Answer 40

fluorescent sensors (using small molecules and nanoparticles)  

Question 41

Why Optical Readouts for Biosensing?

Answer 41

(1) In fluorescent biosensors, changes in intensity or wavelength of light emitted after excitation can be linked quantitatively to the presence or absence of a target analyte. These characteristic responses can be affected in an often predictable and quantitative manner upon binding to specific target analytes. (2) For colorimetric biosensors, the readouts can be interpreted visually without the need for expensive instrumentation – making them amenable for POC devices