Biosensors Without Frontiers: Using Biotechnology to create a Regenerable Supply Chain For PCR In Low Resource Countries

The dynamics of infectious disease (ID) outbreaks requires fast accurate diagnosis for effective management. In low and middle income countries (LMICs), where the disease burden is highest and the cost barrier is limiting, IVD biosensors are often not accessible, so syndromic or presumptive actions are followed. The result is positive cases may go undetected in the community, or mistreated due to wrong diagnosis. This undermines effective clinical decision-making and infectious disease containment.
A significant limitation for the gold standard PCR test also comes from the dependence on global supply chains, highlighted during the Covid-19 pandemic, when countries normally supplying LMICs imposed restrictions on supplies, compromising testing. Furthermore, the routine implementation of PCRs in LMICs remains prohibited by cold chain storage requirements and the high cost of biorecognition and biocatalytic materials required.
Opening the door for lower cost regenerable biorecognition systems and integration in a gold standard PCR platform, this study expands on our previous work, to produce a nucleic acid amplification test (NAAT) for low resource settings. The design focus is on local production and regeneration. Like our earlier LAMP-BST polymerase, an innovative TGP-labelled fused Taq polymerase, incorporating a silaffin peptide is reported. However, unlike LAMP-BST, exceptionally, TGP-Tag is able to sustain heating to 90oC without loss of fluorescence intensity of the TGP,
This has been demonstrated in a nucleic acid diagnostic for malaria and for dengue. The impact of primer dimers is discussed and primer design optimization. Additionally, the use of synthetic biology and design engineering to create a self-packing silica fusion enzymes bioreactor-cartridge is presented to provide dNTPs for PCR. A fully integrated local production and regeneration demonstrator for cholera testing and containment triaging is presented.