Joseph D. Lichtenhan

Background/Objectives: No effective intervention currently exists for non-compressible pulmonary injury, especially in a prehospital setting. Visco-liquids like trisilanol i-octyl POSS could remedy this. POSS resists hemorrhage and activates clotting; this can be augmented with kaolin (22.5%; PK) or chitin (10%; PC). Methods: We tested the efficacy of POSS, PK, and PC in treating incisional lung wounds in swine (39 ± 1 kg; n = 10). An incisional wound was made in the lung via a left thoracotomy, allowed to bleed freely for 30 s, and then no treatment (UNT), gauze with compression (GC), or POSS, PK, or PC was applied (1.5 mL). Each treatment was applied once per animal for a total of 5 wounds. Wounds were observed for 10 min for hemostasis and pneumostasis; GC treatments were assessed at 3 min intervals. Results: POSS and PC produced hemostasis in 8 of 10 wounds; GC: 7 (all significant from UNT); PK: 5 and UNT: 1. PK was not different from any group. POSS (2 ± 0.3 min) and PC (1.4 ± 0.4 min) clotted more quickly than GC (8 ± 3 min); PK was intermediate (3.8 ± 2 min) and not different from any other group. Pneumostasis was achieved in all POSS, PC, and PK, and only after hemostasis in the GC group. Conclusions: Because both POSS and PC provided quick and lasting hemorrhage and pneumatic control in this model, without need for compression, these results support the concept that these types of liquid POSS compounds could prove to be efficacious in prehospital treatment of non-compressible trauma wounds.

Wound healing is a complex dynamic biomechanical process as the body attempts to restore the integrity of traumatized or devitalized tissues. There are four stages of wound of healing that begins with hemostasis followed by inflammation, proliferation and finally weeks later wound remodeling. Full thickness wounds usually are covered with a dressing material after hemostasis, which allows for controlled hydration. We investigated the potential of a visco-liquid hemostat, polyhedral oligomeric silsesquioxane (POSS), for providing hemostasis and to maintain a microenvironment in the wound bed that would maintain moisture content and promote early re-epithelialization. We hypothesized that the hemostatic agent POSS if left in the wound bed would maintain a protective barrier and accelerate wound healing similar to using saline to irrigate the wound to keep the wound moist. We compared the early phase of wound repair (3–7 days) in a porcine full thickness wound model to evaluate the efficacy of the material. Biopsies were taken after 3 and 7 days to determine the acute response of the POSS hemostat or saline on inflammation, cell migration, concentrations of metalloproteinase (MMPs), and tissue inhibitors of metalloproteinase (TIMPs). Accelerated healing was observed in POSS treated wounds by changes in wound contraction, keratinocyte migration, and development of granulation tissue in comparison to saline treated wounds. Increased concentrations at day 3 of MMP-2, MMP-3, and in MMP-1 at day 7 in POSS treated wounds compared to saline coincide with keratinocyte migration observed in the tissue histology and changes in wound contraction. Tissue concentrations of TIMP-1 and TIMP-2 in POSS treated wounds appear to coordinate the sequence of MMP events in the healing tissue. Matrix metalloproteinase-13, a marker for tissue remodeling, was not upregulated in the early wound healing cascade in either POSS or saline treated wounds at 3 or 7 days. Overall, the data suggests POSS treatment contributed to enhanced early cell migration and wound closure compared to saline treatment.

The combination of functional polymers with inorganic nanostructured compounds has become a major area of research and technological development owing to the remarkable properties and multifunctionalities deriving from their nano and hybrid structures

In vitro studies into the interaction of polyhedral oligomeric silsesquioxane (POSS) trisilanols with porcine and human red blood cells (erythrocytes), and mouse fibroblasts is reported. The observations are in agreement with previously reported erythrocyte activity of silanol containing minerals. However the multifunctionality imparted by the POSS silanols provides for their expansion of utility in traumatic hemorrhage and wound care. Further, in vitro tissue studies of i-octyltrisilanol POSS cages are in agreement with reported findings of related POSS serving as tissue scaffolds by providing cellular binding sites and porosity for cellular taxis. The resulting effect is increased rates of tissue healing.