Design, 3D-printing, and characterisation of a low-cost, open-source centrifuge adaptor for separating large volume clinical blood samples

Blood plasma separation is a prerequisite in numerous biomedical assays involving low abundance plasma-borne biomarkers and thus is the fundamental step before many bioanalytical steps. Conventionally, plasma separation is performed using high-capacity refrigerated centrifuges which have the advantage of handling large volume blood samples. These centrifuges are bulky, and prohibitively expensive for low-resource settings, with prices starting from $1,500. Although commercial and existing open-source micro-centrifuges are relatively low-cost, they cannot handle large volume blood samples. Microfluidic blood plasma separation also has been adopted by many researchers to enable low-cost plasma separation, however, these systems still present yield and purity issues for extremely low abundance biomarker detection such as the detection of various fractions of circulating cell-free DNA. To overcome this, we customised the rotor of a commercially available micro-centrifuge [~]$125) using fused filament fabrication to enable centrifugation of large clinical blood samples in resource poor-settings. Our designed adaptor ($15) can hold two 9 mL S-Monovette tubes and maintain the same separation performance (yield, cell count, hemolysis, albumin levels) as the control benchtop refrigerated centrifuge. This low-cost open-source centrifugation system capable of processing clinical blood tubes could be valuable to low-funded laboratories or low-resource settings where centrifugation is required immediately after blood withdrawal for further testing.