Zwitterionic hydrogels implanted in mice resist the foreign-body reaction

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Immunology

Background:

• Implantable biomedical devices face performance limitations due to the foreign-body reaction, characterized by collagenous capsule formation.
• This capsule obstructs essential mass transport and electric communication between the implant and host body.
• Current materials and coatings are insufficient to completely prevent this foreign-body response.

Purpose of the Study:

• To evaluate the efficacy of ultra-low-fouling zwitterionic hydrogels in preventing capsule formation around subcutaneous implants.
• To investigate the host tissue response, including angiogenesis and macrophage phenotype, to zwitterionic hydrogel implants.

Main Methods:

• Subcutaneous implantation of zwitterionic hydrogels in mice.
• Assessment of capsule formation at the implant-host interface over a 3-month period.
• Histological analysis to evaluate angiogenesis and macrophage phenotypes in surrounding tissues.

Main Results:

• Zwitterionic hydrogels significantly resisted capsule formation for at least 3 months post-implantation.
• The hydrogels promoted angiogenesis in the surrounding host tissue.
• Macrophages near the implants exhibited phenotypes associated with anti-inflammatory and pro-healing functions.

Conclusions:

• Ultra-low-fouling zwitterionic hydrogels demonstrate excellent biocompatibility by preventing foreign-body encapsulation.
• These hydrogels may enhance implant performance and promote tissue integration through angiogenesis and modulated immune responses.
• Zwitterionic hydrogels hold promise for developing advanced biocompatible implantable medical devices and tissue scaffolds.