International Journal of Latest Research in Engineering and Technology (IJLRET) ISSN: 2454-5031 www.ijlret.com || Volume 03 - Issue 05 || May 2017 || PP. 48-59 www.ijlret.com 48 | Page Wound healing potential of collagen bilayer dressing on infected dermal wound- A study on rat animal model. Ramasamy Sripriya* 1 , Mohamed Rafiuddin Ahmed 2 and Muthusamy Senthil Kumar 3 1 Senior Research Associate, Central Leather Research Institute, Chennai-600020, India. 2 Research Scientist, BioADD Laboratories, Stanford University, Palo alto, Instructor, Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232 USA. 3 Senior Research Fellow, Central Leather Research Institute, Chennai-600020, India. Abstract: In the current study, a chemically modified collagen bilayer dressing with ciprofloxacin was prepared from type-I collagen. The modified collagen was reconstituted into a membrane and sponge and the drug Ciprofloxacin-HCl was incorporated and fabricated into a bilayer dressing. In vitro release pattern of the dressing was analysed in PBS which recorded release for 6 days. The efficacy of the dressing was checked on infected wound in rat model and compared with that of open infected wound and control group. The healing pattern was analyzed on days 3, 5, 7, 14 and 21 by wound healing rate, biochemical and histological examinations of granulation tissue samples. Integrin expression on the healing wound was analysed using immunohistochemistry and western blotting analysis. In vivo analysis showed significant wound closure, biochemical analysis such as protein, DNA, hydroxyproline, uronic acid, hexoseamine, SOD and catalase from the granulation tissue, showed enhanced healing in the group treated with collagen bilayer dressing with ciprofloxacin. Integrin expression was more in initial stages of healing than the other two groups confirming enhanced healing in treatment group. Histological analysis and wound closure further confirmed proper healing in this group. Our results suggest that sustained bilayer dressing with drug is efficient in controlling and eliminating the bacterial population at the wound site thereby enhancing the healing. Key words: Succinylation; collagen bilayer dressing; drug delivery; ciprofloxacin; wound infection, integrins. 1. Introduction Wound healing is a complex and dynamic cascade of events initiated by injury. The process involves coordinated cell activation, division, chemotaxis, migration and differentiation of many cell types. They are mediated by locally released growth factors and cytokines like interleukins and adhesion receptors like integrins, which may act in an autocrine or paracrine manner. All phases of wound healing are either directly or indirectly controlled by cytokines. It is the balance of these cytokines and other mediators, rather than the mere presence or absence of one or more cytokines, which plays a decisive role in regulating the initiation, progression and resolution of wounds [1-4]. Chemotactic signals attract neutrophils and monocytes to wound sites [5]. The recruitment of fibroblasts in the wound area attracts fibroblasts from surrounding tissues to move into the area of injury and proliferate. The net result is an increased production of very active collagen producing cells. As the new matrix begins to accumulate and fill the void created by the injury, the wound repair mechanism enters a period of transitional phase. The cells undergo marked phenotypic alteration and re-epithelialization of wound begins within hours after injury [6&7]. Fibroblasts deposit loose ECM initially composed of great quantities of fibronectin which activates integrin receptors. Integrins are heterodimers composed of non-covalently associated transmembrane  and  subunits. Most integrin receptors bind ligands that are components of the extracellular matrix including fibronectin, collagen and vitronectin. Certain integrins can also bind to soluble ligands such as fibrinogen, or to counter receptor on adjacent cells, such as Intracellular Adhesion Molecules (ICAMs) leading to aggregation of cells. Signals transduced by integrins play a role in many biological processes including cell growth, differentiation and migration. In the present work, the expression of protein and DNA during healing and the histological analysis of the healing along with the expression of integrin-V in the healing environment at various time intervals representing the granulation, inflammatory and tissue remodeling phase in the presence and absence of collagen and drug incorporated collagen matrix has been studied.