Platelet impersonation

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Science Translational Medicine  30 Sep 2015:
Vol. 7, Issue 307, pp. 307ec169
DOI: 10.1126/scitranslmed.aad3627

Undercover operatives employ disguises to assume new identities and avoid detection. Similarly, artificial materials are often disguised with surface coatings to thwart recognition by the body. Often, however, the molecular signals presented by artificial surface coatings are overly simplistic and easily identified by immune surveillance. These surface coatings can also become fouled by proteins after exposure to blood, triggering a biological reaction. As a consequence, artificial materials in the body are rapidly cleared or encapsulated through a foreign body response.

Hu et al. prepared stealthy artificial polymeric nanoparticles by concealing them within intact platelet membranes. These platelet-mimetic nanoparticles presented 15 different biomolecules, including immunomodulatory proteins, which limited capture by immune cells, and integrin components, which promoted recruitment to injured vasculature. The authors capitalized on the natural adhesion capability of platelets to deliver antimitotic drugs via the membrane-cloaked nanoparticles to regions of coronary restenosis in rats. Opportunistic bacteria often hijack platelets for immune evasion and tissue homing, so Hu and colleagues loaded their nanoparticles with antibiotics, thereby tricking the pathogens and suppressing bacterial growth. This biomimetic, targeted approach could be used for vascular injury in heart disease and cancer, as well as infection in burns and trauma. Major challenges include the large-scale extraction of platelet membranes and reproducible manufacturing of these nanoparticles. Nevertheless, such sophisticated disguises will outfit the next generation of biomaterials for even deeper undercover operations.

C.-M. J. Hu et al., Nanoparticle biointerfacing by platelet membrane cloaking. Nature 10.1038/nature15373 (2015). [Full Text]

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