In vivo experiments were strictly performed accorded with the Guide of National Research Council for the care and use of laboratory animals. The final criteria for hemostasis were no obvious bleeding, no active bleeding and no exudate at the wound site. Prior to testing, all the samples were sterilized by cobalt-60 radiation (15 K) for 1 h.

Liver injury model: Sprague-Dawley (SD) rat (male, 250 g, 5–6 weeks old, n = 18) were provided by Chinese PLA General Hospital. The rats were restrained and anesthetized with 1.5% isoflurane. Eighteen rats were randomly grouped into control, Gauze, and CMC2 groups (n = 6 for each group). The middle lobe of the liver of SD rats was cut to expose. Incision (2 cm) on the liver was created using a scalpel to initiate bleeding [35]. Serous fluid around the liver was carefully removed to prevent inaccuracies in the estimation of the blood weight obtained by the filter papers. CMC sample (3 × 3 cm) was immediately put on the liver cut, and started to record the time. The spilled blood was sucked by a piece of pre-weighed filter paper every 10 s until the hemostasis process was complete. Then the weight of the sample as well as the filter paper with absorbed blood was measured to calculate the mass of total blood loss. In the other experimental group, the cut was treated standard medical gauze until the bleeding stopped. Group without any treatment was used as a blank control.

Femoral artery injury model: The femoral artery injury experiment was performed based on the method described in previous studies [36,37]. Bama miniature pigs (n = 12, female, weighing 24.5 ± 2.1 kg) were used in the experiment. Before operation, the pigs were restrained, pre-anesthetized by injecting 10 w% chloral hydrate (0.5 mL/100 g). The pigs were then fixed in the supine position on the 37 °C thermostatic operation table. One side of the carotid artery was separated, intubated, and connected to MP150 multi-channel physiological monitor to dynamically monitor the heart rate and base mean arterial pressure (MAP) of the pigs before surgery. The surgical procedures were performed by standard aseptic methods. The ear vein of each pig was cannulated, and Lactated Ringer's (LR) solution (5 mL/kg) was administered to compensate for fluid loss. The left femoral artery was cannulated for monitoring and recording of blood pressure, heart rate, electrocardiogram, and body temperature of the animals during the whole experiment. In order to obtain more accurate experimental data, the carotid artery was also monitored, and the recorded data were used as standby data. The pigs were randomly divided into control group (n = 4), Combat gauze group (n = 4) and CMCP group (n = 4). To create a severe hemorrhage in the groin area, approximately 4–5 cm of the right femoral artery was dissected and freed from the surrounding tissues, and then the overlying muscle was removed. The artery was then treated with 10 mL of 5% lidocaine to prevent vascular contraction and vascular spasm. A stabilization period (10 min) was allowed, and then baseline data, including the MAP and other vital signs, were recorded. A stable MAP of 60 mmHg or higher was required before the experiment. The artery was first clamped proximally and distally, and then severed using a surgical scissor. The clamps were immediately released, and free bleeding was allowed for 30 s. The flowing blood was collected with gauze, weighed and recorded as the pretreatment blood loss. While the femoral artery was bleeding, CMCP samples were immediately injected into the wound cavity using a self-made injector with diameter of about 3 cm, and manually compressed against the wound with slight pressure to keep the composites inside the wound. The compression was performed by the same operator in the same way for each animal. Combat Gauze was packed in the bleeding wound in the other group. The injury site was visually checked every 30 s, and the time was recorded when the hemostasis process was complete. The volume of postoperative blood loss was calculated from the change in the weight of gauze and the samples (Combat gauze or CMCPs). The total blood loss was expressed as the sum of the pretreatment blood loss and the posttreatment blood loss. If hemostasis was not achieved or if re-bleeding occurred within 3 min, the sample was removed and replaced with another one. If hemostasis was achieved and was stable for 10 min, the animal was resuscitated intravenously to its baseline MAP with LR solution. Animal survival was defined as the presence of heart beats at the end of 180 min.

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