Tool for developing sensitive multiplex assays via in-solution detection

Wordcloud Colplex

Aim/Technological Description

BIOASTER COLPLEX technology is based on Colicin antibacterial proteins, which are endotoxins released by bacteria during time of stress. This self- destructive bacterial behavior is reversed by their cognate Immunity proteins that bind specifically to the Colicin and inhibit its bactericidal activity.
BIOASTER has harnessed this high-affinity interaction (KD ~ 10-14/-15M) between Colicins and their cognate protective Immunity proteins as a Col-Im- based technology platform, offering a much-needed alternative (or addition) to the long-established avidin/biotin capture system. The new technology is perfectly adapted to point of care diagnosis.

COLPLEX enables the development of a more sensitive test, enhanced multiplexing capacity, and provide the opportunity to produce generic Immunochromatographic (Lateral Flow Assay) support (potential for COGS reduction).
Beyond the improvement of multiplexing capacity (9-plex or more), this emerging technology will make it possible to increase test sensitivity by recognizing the target analyte in solution.

Technology Colplex


The background technology was implemented at BIOASTER to achieve a proof-of-concept to illustrate that beyond the technology’s potential, there is a reality. The proof of principle was carried out on ELISA and then on a 3plex LFA. We have:

  • Redefined the conditions for implementing the Lateral Flow Assay (LFA) and optimized LFA test conditions for the use of recombinant VHH and mAbs.
  • Demonstrated that the technology works with 3 markers targeting two viruses : EBOLA (2 markers) and HIV (1 marker)

We have demonstrated that the sensitivity of the fusion protein-generated Col/Im system is identical to that of the poly- streptavidin reference system.

Evidence / Results

Based on the internal proof-of-concept, BIOASTER has investigated a more realistic application of its technology. through funding from the BMGF (Bill & Melinda Gates Fundation), BIOASTER is currently developing a first 3plex LFA immuno-assay and also demonstrate the feasibility of using the technology in a molecular LFA test.
At this stage and with regard to the objective a developing a field test the following outcomes have been obtained or are currently in progress

  • 3 best pairs selected for multiplexing
  • 3 bioconjugated Im-Ab and/or Im-Ab fusion proteins
  • Dry assay demonstrator with known sensitivity/specificity performances compared to reference assay
  • Protocol of Col/Im use in molecular detection


COLPLEX provides an additional tool for increasing the sensitivity of a simplex test (via detection in solution). Currently, only Streptavidin-Biotin offers the same specificity and affinity, but Streptavidin-Biotin method is susceptible to interference from high biotin concentrations in blood samples and several Streptavidin-Biotin like couples with similar high affinities are not available for multiplex applications.

COLPLEX is also a tool for developing sensitive multiplex assays via in-solution detection, instead of direct spraying which can limit capture probe efficiency. The use of COLPLEX also makes it possible to develop a generic LFA support, facilitating the development of new assays, and potentially reducing production costs (yet to be demonstrated).

Potential Applications

COLPLEX technology can be applied in many different technological contexts and business areas. However, the first area of application is LFA for diagnostics. In this field, there is a need for additional tools to increase the sensitivity of tests, especially multiplex tests.
All diagnostics players developing LFA are potentially interested in having an additional tool for developing higher-performance tests.
Players are particularly interested if they have performance concerns in a current test (simplex or multiplex sensitivity) or have a non-optimal test format to achieve the required performance (notably the use of several strips).


BIOASTER is constantly improving the technology and its robustness. Such improvements may be performed within the scope of a dedicated development targeting the needs of potential IVD company.
To fulfill partners requests, BIOASTER will soon be able to target sensitivity/ specificity performances compared to reference assay and Develop successful isothermal amplification reaction including the Col/Im detection reagents Beyond immunoassays tests, BIOASTER COLPLEX technology has the potential to be compatible with molecular multiplex detection in an LFA format.