Real-time Measurement Technology for intracellular pH in culture

Request Number REQ1369748
Due Date April 3, 2018
Request for Proposal Details
RFP Title
Real-time Measurement Technology for intracellular pH in culture
RFP Description

NineSigma, representing a major food manufacturer, seeks a technology to visualize intracellular pH dynamics in bacterial culture and to conduct real-time pH measurement. Approaches anticipated in this request include pH-responsive fluorescent proteins. Additionally, technologies that are applicable to non-bacterial organisms at this present, such as mammalian cells and yeasts, are also welcomed as long as they are likely to be applicable to bacteria in the near future.




Production of useful substances, such as proteins for pharmaceutical and food applications using bacteria and other microorganisms, are widely conducted. As the production volume of these substances is affected by culture conditions, strict pH control is crucial for stable production.


While sensors and probes used to measure pH changes in entire batches of cultures are already commercially available, it is difficult to understand the state of individual bacterial cells accurately. In the meantime, R&D activities to develop a pH measurement technology for individual bacterial cells by using fluorescent protein as a reporter are widely conducted, and the target includes not only bacteria, but also mammalian cells and yeasts.


Therefore, the client has issued this open request to seek proposals from organizations around the world in order to accelerate the R&D of this technology.

Key Success Criteria


  • Target to be measured: Bacteria (especially, gram-negative bacteria)
  • Anticipated state of bacteria at the time of measurement: Bacteria should be in a subconfluent to confluent state, and the cell density (turbidity) in the culture should be high.
    • Other solid co-exists in the culture broth.
  • Culture volume: Approximately a few hundred mL to tens of L
    • It is anticipated that the culture will be used for lab-scale verification.


Requirements of the proposed technology

  • Should allow inline measurement and reflect the in vivo state


   In the case of an optical detection technology using fluorescent protein:

  • Should be able to detect the state of individual bacterial cells even when the turbidity is high
  • Should not require sampling from the culture
    • If the in vivo state can be maintained outside the culture through the immediate immobilization of bacterial cells, sampling can be acceptable.
  • To maintain inline measurement, the culture can be bypassed using a microflow path, etc.
  • The technology should be applicable to any size and shape of culture vessel.
  • Measurement accuracy: It is preferable that a change of ±0.1 can be detected.
  • It is preferable that the technology has been verified using a prototype (device, bacterial strain); however, a technology currently in under preparation for such is also acceptable.



Possible Approaches

Anticipated approaches for the visualization of pH changes include, but are not limited to, the following:

  • Imaging using ratiometric, pH-sensitive fluorescent proteins as a reporter
  • Ion image sensors
  • pH-responsive nanosensors
  • Other approaches using a substances highly correlated to pH as an indicator


Flow passages and devices used for the inline detection of bacterial cells that have been visualized using the above approaches can be commercially available ones.




Approaches not of interest

  • Technology that targets only the pH measurement of the culture media and that can’t detect the change of individual bacterial cells
  • Technology that is not applicable to bacteria



Preferred Collaboration types
  • Joint Development
  • Technology Licensing
Items to be submitted

Responses will use the Proposal Template which is linked to the “attachments” shown at the bottom of this page and include the following items:


  • Overview of the proposed technology (principle, characteristics)
  • Development stage
  • Current performance
    • Target bacteria/micro-organisms
    • Mechanism of the pH measurement of a single cell
    • Actual measurement data
    • Measurement method used when the above data was obtained (device, conditions, etc.)
    • Influence on culture efficiency (if applicable)
    • In the case of a technology for organisms other than bacteria: Rationale that the technology can be applicable to bacteria
  • R&D plan
  • Request regarding the condtion of collaboration
  • Current status of intellectual property related to the proposed technology
  • Research achievements


Anticipated Project Phases or Project Plan

Respondents should submit proposals using the attached Response Template.


The client will review submitted proposals and possibly ask clarifying questions before selecting the most suitable candidates for collaboration. The client will select the best candidate(s) through evaluations. During the selection process, the client may execute non-disclosure agreements (NDA) with selected respondent(s), seek further information disclosure, and discuss specific development targets or potential opportunities.

The client will execute necessary agreement(s) with the selected respondent(s) and move to the advanced development phase. Specifics of any collaboration will be determined through consultation with the concerned parties.




Area of Interest
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