PolyBall: A new adsorbent for the efficient removal of endotoxin from biopharmaceuticals

Abstract

The presence of endotoxin, also known as lipopolysaccharides (LPS), as a side product appears to be a major drawback for the production of certain biomolecules that are essential for research, pharmaceutical, and industrial applications. In the biotechnology industry, gram-negative bacteria ( e . g ., Escherichia coli ) are widely used to produce recombinant products such as proteins, plasmid DNAs and vaccines. These products are contaminated with LPS, which may cause side effects when administered to animals or humans. Purification of LPS often suffers from product loss. For this reason, special attention must be paid when purifying proteins aiming a product as free as possible of LPS with high product recovery. Although there are a number of methods for removing LPS, the question about how LPS removal can be carried out in an efficient and economical way is still one of the most intriguing issues and has no satisfactory solution yet. In this work, polymeric poly-ε-caprolactone (PCL) nanoparticles (NPs) ( d P = 780 ± 285 nm ) were synthesized at a relatively low cost and demonstrated to possess sufficient binding sites for LPS adsorption and removal with ~100% protein recovery. The PCL NPs removed greater than 90% LPS from protein solutions suspended in water using only one milligram (mg) of NPs, which was equivalent to ~1.5 × 10 6 endotoxin units (EU) per mg of particle. The LPS removal efficacy increased to a higher level (~100%) when phosphate buffered saline (PBS containing 137 mM NaCl) was used as a protein suspending medium in place of water, reflecting positive effects of increasing ionic strength on LPS binding interactions and adsorption. The results further showed that the PCL NPs not only achieved 100% LPS removal but also ~100% protein recovery for a wide concentration range from 20–1000 μg/ml of protein solutions. The NPs were highly effective in different buffers and pHs. To scale up the process further, PCL NPs were incorporated into a supporting cellulose membrane which promoted LPS adsorption further up to ~100% just by running the LPS-containing water through the membrane under gravity. Its adsorption capacity was 2.8 × 10 6 mg of PCL NPs, approximately 2 -fold higher than that of NPs alone. This is the first demonstration of endotoxin separation with high protein recovery using polymer NPs and the NP-based portable filters, which provide strong adsorptive interactions for LPS removal from protein solutions. Additional features of these NPs and membranes are biocompatible (environment friendly) recyclable after repeated elution and adsorption with no significant changes in LPS removal efficiencies. The results indicate that PCL NPs are an effective LPS adsorbent in powder and membrane forms, which have great potential to be employed in large-scale applications.

Multifunctional Biofilter to Effectively Remove Toxins

“…PolyBalls were prepared using the emulsion/solvent evaporation technique. − Briefly, 10 mg/mL of PCL solution in 10 mL of ethyl acetate was injected into 50 mL of 1% poly­(vinyl alcohol) (PVA) solution using a syringe pump ( K d Scientific) at a flow rate of 40 mL/h. The emulsions were homogenized.…”

“…An opportunity to overcome the toxin contamination issue emerged from our recent findings of effective endotoxin removal through its interaction with and adsorption onto nanometer-sized poly-ε-caprolactone (PCL) nanoparticles (NPs) or PolyBalls. − More specifically, when PolyBalls in powder form are mixed with an endotoxin aqueous solution, they were found to remove >99% of endotoxins from solutions. We hypothesize that PolyBalls have the potential to adsorb and remove both endotoxins and cyanotoxins from solutions.…”

Cellulose Regeneration and Chemical Recycling: Closing the “Cellulose Gap” Using Environmentally Benign Solvents

“…The coagulation conditions, cellulose type, and concentration control the film properties. [64] Additives, for example, metal and metal oxides, [65][66][67][68][69][70] activated carbon, [71] dyes, [72] or polymeric nanoparticles, [73] were employed to tailor, modify, or enhance film properties. Blending with additives is not always necessary to achieve better mechanical properties.…”

Development and Characterization of Silver-Doped Multi-Walled Carbon Nanotube Membranes for Water Purification Applications

“…Studies have reported that silver nanoscale particles also act as a binder to bond the carbon nanotubes together [74]. Silver nanoparticles (AgNPs) have been utilized to extract lipopolysaccharides (LPS) from a water mixture, which cause inflammatory reactions, resulting in tissue injury, with up to 97 percent effectiveness [75]. AgNPs can also diminish the regrowth of microorganisms by damaging their cell membranes during the water purification process [76,77].…”