Immunosensors make use of antigen-antibody interactions [1, 2] to detect a wide range of analytes which are of great interest in medical diagnostics, environmental analysis, and forensic medicine [3, 4], including pathogens [5], drugs [6], bacteria [7], toxins [8], and biomarkers [9]. Overall, immunosensors employ the same chemical approach of earliest immunoassays, but offer quicker and simpler analytical procedures that may be conducted at the point-of-care [10]. Immunosensors use an antibody immobilized as a transducer. Antigen-antibody binding event result in electrical or optical changes.
The interaction of the antigen with the immobilized antibody may be monitored using several different detection methods. In this context, electrochemical immunosensors are increasingly being used for biosensing applications [11]. Electrochemical impedance spectroscopy (EIS) is a electrochemical technique, facilitating label-free detection [12, 13], thereby yielding significant advantages in terms of simplicity and rapidity compared to conventional immunosensing processes. The immobilization of an antibody on the transducer element is a crucial step in the preparation of immunosensors [14] [15]. Physical adsorption is the easiest immobilization method, but it suffers from random antibody orientation and poor reproducibility [16-18]. Approximately of 90% antibodies are in an inactive orientation, due to steric blocking of antigen binding sites on these antibodies [12, 19]. More-stable and reproducible antibody binding is achieved by covalent attachment, but this attachment must ensure that antigen binding sites are kept free [20]. For this purpose, antibody coupling to protein G/A has been used [21]. A more simple and effective method for Ab ...
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... urine of a pregnant woman, with a pregnancy of 3 to 5 weeks. The concentration of hCG obtained was 3.5ng/mL (17.4mIU/mL), which was in agreement with the pregnancy status.
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4. Conclusions
In summary, a new impedimetric biosensor for hCG determination in urine has been developed. A simple approach for generating a graphene-aminated surface to which an antibody binding with a suitable orientation for antigen binding is presented. The observed resistance to electron transfer increased linearly with increasing of log(hCG) concentration. The sensor response was not affected by chemical components present in synthetic urine indicating non-specific binding.
The sensor has been applied successfully to quantitatively detect hCG in the urine of pregnant women, suggesting a successful application in point-of-care diagnostics in the near future.
What is the transducer in our sensor scheme (in the assay you used)? What is the most common transducer for commercial glucometers (such as what you would buy at a drug store)? May have to research this. (5 points)
4. A delivery tube with a bung was then placed into the test tube of
electrophoresis. The way the PCR method works is by first mixing a solution containing the
Bioaffinity chromatography is a type of affinity chromatography in which biological compounds such as immunoglobulin-binding proteins, enzymes, lectins, carbohydrates, avidin/biotin system and antibodies are used as ligands (Hage, 2006). Immunoglobulin-binding proteins, namely protein A which is produced by Staphylococcus aureus and protein G which is produced by streptococci, are the ligands that are used in the vast majority of bioaffinity chromatographic applications (Tetala and van Beek, 2010). However, enzymes and enzyme inhibitors can also be used as affinity ligands (Hage, 2006). Immobilized enzymes are widely utilized in many applications, concerning pharmaceutical and food industries. Furthermore, they are used in order to purify enzyme inhibitors, as well as for the removal of impurities from unprocessed extracts. In a similar way, enzyme inhibitors can be utilized for the purification of enzymes from crude extracts (Tetala and van Beek, 2010). The immobilization of enzymes on monolithic stationary phases enables them to be used in a wide range of applications concerning bioaffinity chromatography (Petro, Svec and Fréchet, 1996).
Fischbach, Frances, A Manual of Laboratory & Diagnostic Tests, 4th ed., J. B. Lippincott Company, Philadelphia
With advanced technologies such as this the acidity of the infant’s blood as well as the heart rate can be measured. New
Handbook of Laboratory and Diagnostic Tests with Nursing Implications (3rd edition). Philadelphia: F.A. Davis Company.
...For pregnancy detection, companies producing at home detection tests may want to incorporate detection of hCG-H for greater accuracy in their results. This would allow for optimal detection of pregnancy even before the time of missed menses. For hCG-H testing to be used to clinically determine pregnancy outcome, other laboratories would need to evaluate their own set of data to be able to properly determine if the 13ug/L cut off point found by Sutton-Riley et al. (2006) is viable. Studies would have to take many factors into account including age, race, overall health, and so on, to properly determine what normal values are. Detecting hyperglycosylated human chorionic gonadotropin is changing the way we now look at pregnancies and pregnancy loss. With further research, its full applications in pregnancy outcome and detection are becoming closer to being realized.
The urine you used was diluted by a large amount of water you drank before taking the test. If you did not use the first urine in the morning, which is concent...
During my OSCE, I was able to investigate from the patient that her negative pregnancy test was taken from an “OTC home pregnancy test”. A home pregnancy test made me very suspicious that it was not 100% accurate when comparing it to a HCG serum test. I truly believe that I was able to have an excellent experience because I was so focused on taking a good history.
Biological monitoring is basically evaluating a sterilization process by rendering highly resistant bacterial spores biologically inert. The highly resistant bacterial spores used varies depending on what kind of sterilizer was used. For example Bacillus stearothermophilus spores for steam and chemical vapor sterilizers, Bacillus subtilis spores for dry heat and ethylene oxide sterilizers. These specific Bacillus spores are used because they are more resistant, and present in greater numbers than are the common microbial contaminants found on patient care equipment. If it is proven that these spores have been killed, it is strongly implied that other potential pathogens in the load have also been killed.
The issue is that humoral response will not be effective unless the Fc regions of Ig’s are bound to another molecule. The idea was to develop Ig’s (such as dimeric IgA and pentameric IgM) against zombie virus and the receptor that will recognize some parts of Ig’s attached to antigen and J chain which will undergo conformation change upon binding to antigen. pIg (dimeric IgA and pentameric IgM) bound to Z1H1 will undergo conformational change in its geometry. It is expected that as pIg will bend and cause changes in the conformation. As a result change in J chain is expected which can serve as a receptor for another Ig and used for marking to eliminate zomb...
Biosensor has intensive specificity. Biomaterial only senses definitive ingredient and it is not affected by colour and concentration of measured material.
An alternative approach of affinity chromatography with extremely significant results is dye-ligand affinity chromatography. In this type of affinity chromatography, dyes compose the group of ligands than are employed in the technique (Hage et al., 2012).
Langmuir adsorption model assumesthat adsorption occurs at specific homogeneous adsorption sites onthe adsorbent surface and intermolecular forces decrease rapidlywith the distance from the adsorption surface. The model further basedon the assumption that all the adsorption sites are energeticallyidentical and adsorption occurs on a structurally homogeneousadsorbent. The Langmuir (Hadi et al., 2010) non-linear form is pre-sented in Eq. (6).which may be unfavourable (RL > 1), linear (RL = 1), favorable (0 < RL< 1) or irreversible (RL = 0) [31,32]. It has been found from Fig. 8 that the values of RL for TG range from 0.0068 to 0.039 and for ATG was 0.02 to 0.13. The lower RL values at higher BG concentration indicate that adsorption is more favourable at higher concentrations. The degree of favourability tended toward zero (the completely ideal irreversible case) rather than unity (which represent a completely reversible case). Thus the adsorp-tion of BG on to both gels is confirmed to be a favourable process.