Multifunctional Biofilter to Effectively Remove Toxins

The goal of this work is to synthesize a multifunctional biofilter and assess its efficiency to remove endotoxins, freshwater harmful algal bloom (FHAB)-derived cyanotoxins, and toxic heavy metal ions from water using polymeric nanoparticle (PolyBall) embedded in a soy protein isolate (SPI)-derived cellulose acetate (CA) biofilter. The presence of even a trace number of endotoxins in biopharmaceutical solutions can create a pyrogenic response in the human body by triggering the immune system’s signaling cascade. The purification of products usually involves sequential ion-exchange chromatography, gel filtration, and/or ultrafiltration that are complex and expensive and are associated with high (>40%) product loss. The water treatment plants use a series of standard cleansing procedures to diminish cyanotoxins; however, finding an effective and affordable technique remains a challenge. We have developed a PolyBall scavenger of endotoxins, based on nonporous poly-ε-caprolactone (PCL) polymer nanoparticles (PCL NPs) that are capable of removing endotoxins from protein solutions at high efficiency (>99%) while maintaining >99% protein recovery. In this work, we put our efforts incorporating PCL NPs (PolyBalls) in SPI and CA biofilters to achieve improved efficiency in removing endotoxins, cyanotoxins, and toxic heavy metal ions such as lead ions from contaminated solutions. Six different recombinant protein solutions of molecular weights varying from 14 to 341 kDa and with isoelectric points (pI) varying from 4.5 to 10.7 were spiked with 5.74 × 105 EU/mL of endotoxins. The contaminated protein solutions were passed through biofilters that showed >99% of endotoxin removal from the solutions while maintaining >99% protein recovery. The biofilter exhibited excellent capability in cyanotoxin separation from surface water collected from three different lake water. This is the first demonstration of soy protein plant-based portable filters with embedded biocompatible polymeric NPs, which provide strong adsorptive interactions for toxin removal from protein solutions and surface water.