Integrated GelMA and interleukin 8-loaded liposome composite scaffold for endogenous BMSCs recruitment in bone repair

Bone repair strategies, based on endogenous stem cell recruitment, can effectively avoid immune rejection and the low utilization of exogenous stem cells. Endogenous stem cells can be recruited to the implantation site by loading chemokines onto bone tissue-engineered scaffolds. However, challenges such as unstable chemokine activity and easy inactivation after implantation remain significant. In the present study, composite fiber scaffolds ((IL8@LIP)-GelMA) consisting of Interleukin 8 (IL8) -loaded liposomes and GelMA were constructed by electrospinning and photocrosslinking, and its ability to recruit bone marrow-derived mesenchymal stem cells (BMSCs) and immunomodulatory effect was investigated. Compared to GelMA loaded directly with IL8, scaffolds of (IL8@LIP)-GelMA demonstrated superior protection of IL8 activity, ensuring a slow and continuous release. Both in vivo and in vitro experiments demonstrated that the (IL8@LIP)-GelMA scaffolds effectively recruited BMSCs to the desired sites. Additionally, the (IL8@LIP)-GelMA scaffolds exhibited the capacity to recruit more macrophages to the implantation site. Importantly, they promoted the polarization of macrophages toward the M2 anti-inflammatory phenotype, facilitating the transition from the inflammatory stage to the tissue repair stage. Therefore, (IL8@LIP)-GelMA scaffolds show great potential for cell-free tissue engineering applications and provide insights into the loading mode of growth factors in scaffolds.