{
  "id": 8169767,
  "title": "Modular PEGylation Confers Reduced Immune-Cell Uptake and Enhanced Pharmacokinetic Performance to Encapsulin Protein Nanocages",
  "url": "https://urgent.news/2026/09/17/modular-pegylation-confers-reduced-immune-cell-uptake-and-enhanced",
  "topic": "health",
  "section": "Health & Medicine",
  "published": "2026-09-17T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.12.751196v1?rss=1"
  },
  "original_language": "en",
  "account": "Encapsulins are self-assembling protein nanocages that show promise as systemic drug delivery systems, though their pharmacokinetics are not well understood. This study demonstrates that modular PEGylation of encapsulin nanocages, decorated with SpyCatcher, can significantly decrease macrophage uptake and enhance systemic circulation. PEGylation achieved 82% efficiency, with an estimated 49 PEG chains per Am-S nanocage, without affecting the structure or stability of the nanocages. The PEGylated Am-S retained its solubility and protein integrity through multiple freeze-thaw cycles and six months of storage. In vitro experiments showed that PEGylation reduced nanocage association and internalization by RAW 264.7 macrophages compared to non-PEGylated nanocages. Following intravenous administration in BALB/c mice, the PEGylated nanocages exhibited significantly prolonged circulation, with 50% of the injected dose remaining after one hour, compared to just 2.6% for the non-PEGylated Am-S. With a circulatory half-life of 1 hour and 43 minutes, this represents the first pharmacokinetic analysis of an encapsulin nanocage. The findings highlight the potential of controlled PEGylation to reduce macrophage interactions and extend the circulation time of encapsulin nanocages in vivo, improving their therapeutic potential.",
  "summary": "Encapsulins are self-assembling prokaryotic protein nanocages with growing potential as systemic drug delivery systems, but their pharmacokinetic behaviour remains poorly characterised, and rapid immune recognition and clearance may limit delivery to target tissues. Here, we show that modular PEGylation of a SpyCatcher-decorated encapsulin Alkaliphilus metalliredigens (Am-S) markedly reduces…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}