How to determine cutoff for an IVD assay?

How to determine LoD, LoQ, Linearilty, Cutoff, Expected values for an IVD assay (infectious disease or physiological state monitoring eg. hormones). Has anyone preformed these, can you explain...

01 February 2020 2,896 3 View

Monoclonal antibodies both capture and detection raised in murine?

Hi, I have come across an IVD quantitative assay for C-peptide where both anti analyte biotin-conjugated antibody which binds to Strep coated wells and HRP conjugated anti-analyte antibody was...

31 December 2019 3,639 3 View

Test for pre-existing antibodies against AAV?

02 March 2019 5,080 7 View

How is enzyme unit defined with respective to substrate concentration?

01 February 2019 358 5 View

CTG assay (CellTiter-Glo) ATP generated?

"The homogeneous "add-mix-measure" format results in cell lysis and generation of a luminescent signal proportional to the amount of ATP present. The amount of ATP is directly proportional to...

10 November 2018 3,993 2 View

After passaging the cells for 24 times, what will be the generation number?

After reviving the cells from -80C and seeding the cells ~1 million in T25 flask when the cells reach 80% confluency then if I passage/subculture the cells for eg. spleen (finite) or CHO or...

06 July 2018 486 7 View

Blue White Screening?

31 December 2017 3,468 7 View

Surfactant vs Defoamer?

Can surfactant and defoamer be used at the same time?. Surfactant (an amphiphilic) works based on reducing the surface tension of water binding thru hydrophobic interaction and hydrophilic...

31 December 2017 3,884 5 View

Final concetration 10% DMSO?

If I had 28million cells/ml (A) and require 11million cells/ml. I add 392.85 ul from (A) + 607.15 ul of 19.4% (since it is 0.6 times more) DMSO. Now final Conc. of DMSO is 10%? Explain with...

11 December 2017 2,952 1 View

Competetive ELISA result interpretation?

Coated antigen conc. used 50ng/100ul antigen1 (is an antibody) conc. 100ng/100ul + purified Mab conc. 1000ng/100ul antigen1 is an recombinant Mab with human Fc region against peptide conjugated...

10 November 2017 4,603 7 View

Buffer to disrupt platelet alpha granules for PF4 quantification?

Hello! I want to quantify by ELISA the secreted (from platelets poor plasma) and the non-secreted (from platelet lysate) PF4 before and after TRAP stimulation. I will use the ELISA from R&D...

03 March 2021 1,499 2 View

Buffer Exchange using column packed with sephadex G-25 effect on protein concentration?

Hello, If i am doing a buffer exchange for an antibody of 1mg/mL, does the elution lose protein in the process of buffer exchange? For example, if i flow through 500 uL of 1mg/mL sample, and...

03 March 2021 6,299 3 View

How optimize the Size Exclusion Chromatography?

Hello! I'll do a size exclusion chromatography, but I only have an open column, and I'll perform the peptide extraction from yeast, using buffer lysis (sodium phosphate 50 mM/NaCl 30 mM/DNAse and...

01 March 2021 2,215 2 View

Why are my bands weird in this Agarose gel?

Can someone please give me some possible things that could go wrong? Here is my recipe: 0.5g Agarose 50 mL of TAE 1x 1 uL ethyl bromide. Gel was run at 100V for 1 hour. The buffer used is also TAE.

01 March 2021 9,952 3 View

What do I do with DLS peaks that are from the buffer?

I'm looking at the aggregation of my protein sample using DLS. Unfortunately, my buffer (20mM HEPES) also results in a set of peaks. These are at approximately 1 and 1000 d.nm. The lowest peak...

01 March 2021 9,015 2 View

What is the most suitable resuspension buffer for TCA/acetone precipitated protein?

I need to extract protein from fermented carbon sources for Bradford assay. Most researchers experiencing insolubility of pellet in resuspension buffer. Please assist me to select most suitable...

26 February 2021 7,129 3 View

What urea buffer can i use for biotagged protein extraction from streptavidin beads?

Hi all, I have been doing research on biotagged LDB1 proteins in Mel cells. I purify the proteins using M280 streptavidin beads. The yield is very low so I've been trying to optimize it by...

24 February 2021 5,749 3 View

Cloudy/high background western blot - can anyone help me?

Hi everyone! I try to detect VDR protein (~48 kDa) using Western Blot. After SDS-PAGE using 10% MP TGX Stain-Free Gel from BioRad I transferred the protein onto an metOH activated PVDF membrane...

23 February 2021 6,266 3 View

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22 February 2021 9,932 11 View

How to get/count refractive index in gasses?

20 February 2021 8,202 6 View