Study of uricase-polynorbornene conjugates derived from grafting-from ring-opening metathesis polymerization.

PEGylation has been the 'gold standard' in bioconjugation due to its ability to improve the pharmacokinetics and pharmacodynamics of native proteins. However, growing clinical evidence of hypersensitivity reactions to PEG due to pre-existing anti-PEG antibodies in healthy humans have raised concerns. Advancements in controlled polymerization techniques and conjugation chemistries have paved the way for the development of protein-polymer conjugates that can circumvent these adverse reactions while retaining the benefits of such modifications. Herein, we show the development of polynorbornene based bioconjugates of therapeutically relevant urate oxidase (UO) enzymes used in the treatment of gout synthesized by grafting-from ring-opening metathesis polymerization (ROMP). Notably, these conjugates exhibit comparable levels of bioactivity to PEGylated UO and demonstrate increased stability across varying temperatures and pH conditions. Immune recognition of conjugates by anti-UO antibodies reveal low protein immunogenicity following the conjugation process. Additionally, UO conjugates employing zwitterionic polynorbornene successfully avoid recognition by anti-PEG antibodies, further highlighting a potential replacement for PEG.

Poly(Oxanorbornene)-Protein Conjugates Prepared by Grafting-to ROMP as Alternatives for PEG.

PEGylation is the gold standard in protein-polymer conjugation, improving circulation half-life of biologics while mitigating the immune response to a foreign substance. However, preexisting anti-PEG antibodies in healthy humans are becoming increasingly prevalent and elicitation of anti-PEG antibodies when patients are administered with PEGylated therapeutics challenges their safety profile. In the current study, two distinct amine-reactive poly(oxanorbornene) (PONB) imide-based water-soluble block co-polymers are synthesized using ring-opening metathesis polymerization (ROMP). The synthesized block-copolymers include PEG-based PONB-PEG and sulfobetaine-based PONB-Zwit. The polymers are then covalently conjugated to amine residues of lysozyme (Lyz) and urate oxidase (UO) using a grafting-to bioconjugation technique. Both Lyz-PONB and UO-PONB conjugates retained significant bioactivities after bioconjugation. Immune recognition studies of UO-PONB conjugates indicated a comparable lowering of protein immunogenicity when compared to PEGylated UO. PEG-specific immune recognition is negligible for UO-PONB-Zwit conjugates, as expected. These polymers provide a new alternative for PEG-based systems that retain high levels of activity for the biologic while showing improved immune recognition profiles.

Polynorbornene-based bioconjugates by aqueous grafting-from ring-opening metathesis polymerization reduce protein immunogenicity.

Protein-polymer conjugates (PPCs) improve therapeutic efficacy of proteins and have been widely used for the treatment of various diseases such as cancer, diabetes, and hepatitis. PEGylation is considered as the "gold standard" in bioconjugation, although in practice its clinical applications are becoming limited because of extensive evidence of immunogenicity induced by pre-existing anti-PEG antibodies in patients. Here, optimized reaction conditions for living aqueous grafting-from ring-opening metathesis polymerization (ROMP) are utilized to synthesize water-soluble polynorbornene (PNB)-based PPCs of lysozyme (Lyz-PPCs) and bacteriophage Qß (Qß-PPCs) as PEG alternatives. Lyz-PPCs retain nearly 100% bioactivity and Qß-PPCs exhibit up to 35% decrease in protein immunogenicity. Qß-PPCs derived from NB-PEG show no reduction in recognition by anti-PEG antibodies while Qß-PPCs derived from NB-Zwit show >95% reduction as compared with Qß-PEG. This work demonstrates a new method for PPC synthesis and the utility of grafting from PPCs to evade immune recognition.

Engineering Spherically Super-Structured Polyamides for the Sustainable Water Remediation.

Unlike metal-ornamented hybrid material and linear polymers, we invoked the growth of a biodegradable superstructured cross-linked polyamide-ester material. The material is thermally stable. The thiol-alkene photoclicked material acted as an efficient water remediator. The material efficiently monitored amphiphilic dyes like rhodamine B (RHB), methylene blue (MB), and chronic mercuric ions in water. The adsorption kinetics revealed the material could adsorb >95% dyes within 24 h. The RHB-functionalized polymer could sense mercuric ions too. The Density functional theory (DFT) calculation shows a chelated mercury complex with thioether in the polymer, Poly-Am-RhAll, to form a comparatively more stable complex.