Biomedicine - Blog Posts

ELISA

Enzyme-linked immunosorbent assay is a plate-based assay technique used to detect substances such as proteins, peptides and hormones. 

An antigen is immobilized on a solid surface 

It is complexed with an antibody that is linked to an enzyme.

The conjugated enzyme activity is assessed via incubation with a substrate.

Which produces a product that can be measured. 

Direct ELISA

Antigen is coated directly to wells of microtitre plate 

an enzyme-labelled primary antibody that detects the antigen is added.

Advantages  

Fast and minimal steps needed.

Minimum precursor requirement makes it less error prone.

Disadvantages

The immobilization of the antigen is not specific - background interference.

Less flexibility of primary antibody.

No signal amplification –> less sensitivity.

Indirect ELISA

An enzyme labelled secondary antibody interacts with a primary antibody to increase sensitivity. 

Advantages

Offers high sensitivity and flexibility as a secondary antibody can label different primary antibodies

It is cheap (fewer labelled antibodies needed)

Disadvantages

Increased background noise from the secondary antibody.

Extra labour.

Sandwich ELISA

Capture antibody bound to surface.

Antigen-containing sample is applied and captured.

A specific antibody is added, and binds to antigen (sandwiching the antigen between 2 antibodies). 

Enzyme-linked secondary antibodies are used as detection antibodies.

Advantages  

Offers high sensitivity and a highly specific reaction due to 2 antibodies (both have to bind to the antigen).

Disadvantages

For recognition of a specific epitope, only monoclonal antibodies can be applied as matched pairs.

Procuring monoclonal antibodies is difficult and expensive.

look at these gorgeous bronchial cartilage cells!

look at that inflammatory process!!

this is a intestinal polyp slide. also check out that hemossiderosis in the hemorraged vessel to right!

Metastatic embolus from breast adenocarcinoma in the lungs

cancer cells are usually very metamorphic, which you can tell by the different shapes of the nuclei in this embolus. i love how you can see the metastasis inside a vessel perfectly in this picture!

Rebloging again cause it's insane how much my life has changed these past few months. I moved to another city, another state, I made a lot of new friends, I'm in college and loving every bit of it. For real, my past self wouldn't believe that we made it and we're so damn happy!!

I'm so happy those past few days, because everything has been working my way. And yesterday I just received the results from a college entrance exam and I placed so well among all the people. I'm pretty sure I'll be receiving my entrance confirmation soon.

And it's all because I have been believing myself like I have never done before, and it's so freeing and exhilarating to know that I can have absolutely anything I want from now on.

So do a favor to yourself and believe! I know I'm doing it and it's working!

Almost two months later, but I got my entrance confirmation!!!

Starting August, I'll be an official college student💫📚

I'm so happy those past few days, because everything has been working my way. And yesterday I just received the results from a college entrance exam and I placed so well among all the people. I'm pretty sure I'll be receiving my entrance confirmation soon.

And it's all because I have been believing myself like I have never done before, and it's so freeing and exhilarating to know that I can have absolutely anything I want from now on.

So do a favor to yourself and believe! I know I'm doing it and it's working!