Self-Driven “Microfiltration” Enabled by Porous Superabsorbent Polymer (PSAP) Beads for Biofluid Specimen Processing and Storage

Abstract

A remote collection of biofluid specimens such as blood and urine remains a great challenge due to the requirement of continuous refrigeration. Without proper temperature regulation, the rapid degradation of analytical targets in the specimen may compromise the accuracy and reliability of the testing results. In this study, we develop porous superabsorbent polymer (PSAP) beads for fast and self-driven “microfiltration” of biofluid samples. This treatment effectively separates small analytical targets ( e.g. , glucose, catalase, and bacteriophage) and large undesired components ( e.g. , bacteria and blood cells) in the biofluids by capturing the former inside and excluding the latter outside the PSAP beads. We have successfully demonstrated that this treatment can reduce sample volume, self-aliquot the liquid sample, avoid microbial contamination, separate plasma from blood cells, stabilize target species inside the beads, and enable long-term storage at room temperature. Potential practical applications of this technology can provide an alternative sample collection and storage approach for medically underserved areas.

Self-Driven Pretreatment and Room-Temperature Storage of Water Samples for Virus Detection Using Enhanced Porous Superabsorbent Polymer (PSAP) Beads

“…Our previous study has con rmed that PSAP treatment could effectively avoid the impact of bacteria together with their released protease on the protein target encapsulated inside the beads. 45 It can be deduced that similar effects should apply to virus preservation. The pH inside the beads was pre-set to a designed value slightly higher than 7, providing an intrinsic buffer system.…”

“…The design principle and synthesis of the pristine PSAP beads were previously described. 45 In brief, the reaction mixture containing 6 wt% sodium acrylate, 4 wt% acrylamide, 10 wt% poly(ethylene glycol) (PEG, average M n =6000 g mol −1 ) and 0.2 wt% N,N'-methylenebisacrylamide in DI water was prepared. The liquid mixture was fully dispersed and degassed by nitrogen bubbling for 5 min.…”

“…The concentration of MS2 was quanti ed by the double agar layer method with three replicates for each sample. 45 The recovery e ciency of the viruses was determined by comparing the concentration of the viruses released from the PSAP beads (c t ) and in the original liquid sample (c 0 ). In brief, 5 PSAP beads were applied to treat 2 mL of the virus sample.…”

“…By adjusting the porogen amount in the precursor, this critical parameter can be tuned to control the threshold diameter of absorbable species. 45 Following the design principles, the PSAP beads have been optimized to enable an effective separation of viruses (<0.5 μm) and undesired large components (>1 μm) in water samples by absorbing the former inside and excluding latter outside the beads (optimization process not shown in this study). Thus, the viruses stored inside the beads will not be affected by those undesired components.…”

“…43,44 In our previous study, we have successfully developed and demonstrated porous superabsorbent polymer (PSAP) beads for fast, effective, and self-driven "micro ltration" treatment of bio uid samples. 45 The PSAP beads allowed the sorption of analytical targets that are typically small molecules or macromolecules (e.g., ions, sugars, proteins, and nucleic acids) while rejecting large undesired components (e.g., bacteria and blood cells).…”