Actively cross-linking hemostatic sealant enables rapid hemostasis and wound closure.

A rapid hemostatic sealant can save a patient's life from shock and death due to severe trauma or excessive bleeding from the wound site during surgery. However, an ideal hemostatic sealant needs to meet the standards of safety, efficacy, usability, cost, and approvability and overcome new challenges. Here, we devised a combinatorial hemostatic sealant of PEG succinimidyl glutarate-based cross-linking branched polymers (CBPs) and the active hemostatic peptide (AHP). After ex vivo optimization, the best hemostatic combination was called an active cross-linking hemostatic sealant (ACHS). Interestingly, ACHS formed cross-links with serum proteins, blood cells, and tissue and interconnected coating on blood cells, which might induce hemostasis and tissue adhesion based on SEM images. Moreover, ACHS showed the highest coagulation efficacy, formation, and agglomeration of thrombi within 12 s, and in vitro biocompatibility. Mouse model experiments represented rapid hemostasis within 1 min, wound closure of the liver incision, and less bleeding than the commercialized sealant with tissue biocompatibility. ACHS has the advantages of rapid hemostasis, mild sealant, and easy supply by chemical synthesis without inhibition by anticoagulants, which might minimize bacterial infection by immediate wound closure. Therefore, ACHS could become a new-type hemostatic sealant to match surgical needs for internal bleeding.

Efficient and safe small RNA delivery to macrophage using peptide-based nanocomplex.

As one of the gene therapies, RNA interference (RNAi) effectively suppresses only specific genes, targeting various diseases in which they are involved. For the successful process of RNAi, efficient and safe delivery of small RNAs, including small interfering RNA and short hairpin RNA, is essential. Herein, an S-R11 fusion peptide, SPACE peptide conjugated with poly-arginine, was introduced to deliver small RNAs into immune cells that are difficult to transfect. This S-R11 peptide stably formed a spontaneous self-assembling nanocomplex through electrostatic attraction and hydrogen bonding with small RNAs. The nanocomplex showed about 5.3-fold better permeation efficiency than the conventional Lipofectamine™ 2000 for RAW 264.7 macrophage cells. Moreover, it induced about 66.2% silencing effect of the target gene in the cells activated with polyinosinic:polycytidylic acid (poly (I:C)). In addition, the cell viability of fusion peptide was ensured even in a concentration range exceeding the concentration used in the nanocomplex. Based on these results, it is expected that the nanocomplex in this study can be used as a new gene delivery system that can overcome the challenge of gene therapies to immune cells.