1) [50%] A protein-functionalized sensor for the capture and detection of a spec

Question

1)   [50%] A protein-functionalized sensor for the capture and detection of a specific protein, hapten, immunoglobulin, viral or bacterial analyte (e.g. an antibody-functionalized QCM sensor for the detection of prion proteins). [HINT: The sensor surface should be functionalized WITH a protein to detect another biomolecule. The target molecule you are detecting need not be a protein]

2) [50%]  A carbohydrate-functionalized sensor for the capture of a specific protein, bacterial or viral target (e.g. a human milk glycan functionalized SPR chip for the capture of norovirus capsids). [HINT: Your sensor should be functionalized WITH a carbohydrate. The target molecule does not need to be a carbohydrate]

3)  [50%]  A DNA-functionalized sensor for the capture of a nucleic acid or DNA-binding protein (e.g. a DNA-functionalized microelectrode array for DNA hybridization).

NOTE: For your two sensors, you must include a specific chemistry for surface modification, a specific surface capture molecule (protein, carbohydrate, and/or nucleic acid), and specific target molecule for detection.

Guidelines:

1)   Each biosensor must be based on a different detection/senor modality. So you will need to design a unique sensor for each of the aforementioned applications (Protein, Carbohydrate, DNA). Examples include, but are not limited to:
·      Surface Plasmon Resonance
·      Quartz Crystal Microbalance
·      Conventional Fluorescent Microarray
·      Whispering gallery mode resonator
·      Silicon microring resonator biosensor
·      Nano field effect transistor
·      Mach-Zehnder Interferometer
·      Young’s Interferometer

2)   Illustrate detailed chemical scheme for how you will functionalize your biomolecule to the surface of the sensor (e.g. if you wanted to functionalize a protein to a gold SPR chip, you should could show the assembly of an amine-terminated SAM, followed by carbodiimide coupling of. the protein). These schemes should be drawn using a chemical illustration software package (ChemDraw / ChemSketch).Your chemical schemes should be as detailed as necessary to accurately depict the chemical design of your system, however step-wise mechanism is not necessary. You should include at least one literature reference to support your conjugation strategy.

3)  Include a detailed illustration of the functional sensor, and describe whether the sensor is label-free or not, what signal is observed, and how you would detect the interaction (i.e. if a labeled antibody is required, you should describe what label would be needed). Don’t go overboard with detail, a single illustration would suffice (see attached illustration of the nano field effect transistor as an example).

4)   Include a VERY brief (~200-300 word) description of each platform, including what SPECIFIC interaction you would observe, and at least one reference of your choosing on the biosensor platform you are using. Details should include the SPECIFIC MEDICAL/RESEARCH NEED for the sensor, what it is detecting, and how that information can be used.

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Explanation / Answer

1) The most common bioelements used in the development of electrochemical immunosensors are Abs, followed by Apt, and in the last five years the miRNA. In order to perform an early diagnosis, a method that is able to measure peptides and proteins directly in a sample, without any sample pre-treatment or any separation, is preferred. This direct detection can be performed with methods making use of the specific interaction of proteins with Ab, Apt and miRNA. An impedimetric immunosensor was developed for the detection of Salmonella thyphurium in milk samples. Gold electrodes were functionalized with: single 11-amino-1-undecanethiol (MUAM); a mixture of MUAM and 6-mercapto-1-hexanol (MCH); and a mixture of MUAM, MCH in the presence of triethylamine (TEA) to prevent formation of interplane hydrogen bonds among amine-terminated thiols. Specific Abs were then immobilized via SAM that served to capture the Ag from samples, resulting in changes of the resistivity of the solution. Signal amplification was obtained by performing the measurements in the sample media, which offered several advantages such as: higher response in shorter time due to simultaneous proliferation of the viable bacteria cells in the tested samples, insensitivity to the presence of dead cells, and elimination of the centrifugation and washing steps that are normally used to isolate bacterial cells. The results showed the importance of MCH in SAMs while the addition of TEA had rather negative effects. For a detection time of 2 h, the MUAM-MCH-based sensor provided reliable analytical signals for a concentration of three orders of magnitude lower than the infectious dosage of S. typhimurium [138]. Listeria monocytogenes can be transmitted to humans through consumption of contaminated food, such as smoked fish, poultry, meat and dairy products, and ready-to-eat foods [139, 140]. An impedance immunosensor for the detection of Listeria monocytogenes using TiO2 nanowire bundle microelectrodes as the Ab immobilization platform was reported. The TiO2 nanowire bundle was prepared through a hydrothermal reaction of alkali with TiO2 powder and connected to the gold microelectrodes by mask welding. Impedance changes were investigated after the formation of nanowire-Ab-Ag complexes and correlated to bacterial number. The immunosensor was able to specifically detect 10 cfu/mL Listeria monocytogenes [141]. Ochratoxin A (OTA) is a thermostable mycotoxin produced by species of Aspergillus or Penicillium fungi, which contaminates a high variety of food stuffs, such as cereals, dried fruits, coffee, grapes, wine and beer, with nephrotoxic and carcinogenic effects on mammali

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