Polymerase chain reaction (PCR) droplet machine

Background – Purpose of the Project

Eccel’s customer is a leading provider of droplet digital polymerase chain reaction (PCR) machines, commonly used for determination of the abundance of DNA alleles within a DNA sample.

Our customer’s precision digital PCR droplet machine integrates droplet generation, thermal cycling and droplet reading into a single machine that is a fully automated and digitally integrated PCR system.

Once plates and bottles are loaded, the consumption needs to be monitored by the machine and levels of each reagent needs to be monitored automatically. The user needs to be automatically alerted ahead of time when reagent levels are low and require changing which helps to reduce machine down-time by enabling the end user to proactively stock reagents required for the digital polymerase chain reaction process.

It is also important that only legitimate consumables are loaded into the machine, so it was necessary to implement a solution which removed any risk of counterfeit products being used.

 

Challenges to address

The first challenge to address was to develop a novel human error free way of selecting a unique address for each RFID reader/writer module on the internal RS485 bus, and secondly port the functionality of our Pepper C1 range over to a different MCU based platform (STM32 MCU from STMicroelectronics) that did not contain a Wi-Fi capability.

The latter requirement meant that Eccel had to replace many of the features available via the Web Interface on standard Pepper C1 devices with commands sent via the RS485 interface.

Plus we also needed to obtain regulatory approvals for RF emissions and susceptibility in multiple countries including USA, Canada, Europe, UK, Japan, South Korea.

 

Technology Developed

Eccel developed custom RFID modules to communicate to the machine host system via addressable RS485. There are 8 Eccel modules in each machine.

Eccel also provide high security custom tags with custom printing and additional space for our partner customer to print batch specific information on the label, as well as encrypt it during the process of applying it to the consumables. These tags are specially tuned to work with our readers which provides maximum read range and reliability for the customer.

Once these RFID labels are on the loaded consumables, they can be read from and written to by Eccel’s embedded readers in the PCR machines.

These enable users to monitor levels of reagents automatically using the on-board touch screen which displays data provided from the integrated RFID reader and tags.

This integrated RFID facilitates process automation and ease of data analysis for the end operator. Our customer can then use this RFID capability to sell consumables pre-labelled with our RFID tags to ensure their end customers must purchase their consumables for use within the PCR machine.

This model ensures repeat business and allows our customer to provide low up-front cost machines to their customers and associated consumables that are ready to use, therefore minimising the time required for system set-up and calibration when changing consumables.

The Eccel product developed for this application is available to buy and view in detail here:  https://eccel.co.uk/product/rs485-fcc-ised-red-rfid-reader/

These cartridges, gaskets, and consumables are required for experiments with Droplet Digital (ddPCR) PCR Systems.