SBIR-STTR Award

The objective of this Phase I study is to develop novel hydrogel-based tissue expanders that have delayed expansion with the capacity to be reshaped by the surgeon. Currently, plastic surgery routinely uses silicone balloon-type tissue expanders or self-inflating expanders. Balloon-type tissue expanders require multiple visits and exterior equipment to generate expansion. Current self-inflating expanders expand immediately which may damage sutures related to the implantation wound. Neither of these technologies has the capability to be easily reshaped at the time of surgery. Given the wide range of tissue shapes and sizes encountered in the human body, the ability to reshape the expander by the surgeon with scissors and scalpels is desirable. This study will initially focus on expanders for use in dental surgery; however the same principles can be utilized for other tissues. The proposed hydrogel- based tissue expander will utilize biodegradable cross-linkers to delay swelling for 2-3 weeks so that surrounding tissues may heal from implantation prior to expansion. For shaping the proposed expander should also be elastic and flexible. The properties to be optimized in this study will be delayed swelling and flexibility Specific Aim 1 is the synthesis and characterization of biodegradable cross-linkers. These cross-linkers will utilize a biodegradable spacer. The materials used for this spacer chemically react in the presence of water generating non-toxic degradents which are either metabolized or excreted from the human body by a variety of mechanisms. These spacer units will be end-capped with non-degradable cross-linker units which hold the polymer chains of the hydrogel together until degradation occurs, thus slowing the rate of swelling. Specific Aim 2 is the characterization of delayed swelling hydrogels generated using these biodegradable cross-linkers. These cross-linkers will be incorporated into existing hydrogel technology to generate delayed swelling hydrogels. These hydrogels will be tested to determine their swelling pressure, degradability, elastic properties and mechanical properties. Successful completion of this Phase I study will generate novel, delayed-swelling, hydrogel based, tissue expanders which do not suffer the drawbacks of current tissue expansion technologies. These tissue expanders will not swell until sufficient healing has occurred for tissue expansion. These tissue expanders will not require multiple visits utilizing exterior equipment such as pumps and valves. These tissue expanders will also be easily re-shapable by the surgeon to custom fit certain tissues using tools readily available such as scissors. Phase II development will focus on creating a marketable prototype and animal studies. The objective of this research is to generate re-shapable, delayed-expansion, hydrogel-based tissue expanders for use in dental and reconstructive surgery. These tissue expanders will overcome problems associated with current technology such as eliminating exterior equipment and allowing custom fitting of the expander to the tissue by the surgeon. This technology will reduce the incidence of morbidity associated with this surgery thus promoting general public health

The objective of this Phase II study is to develop novel hydrogel-based tissue expanders that have delayed expansion with the property to be reshaped by the surgeon. Current tissue expanders either require external inflation or are immediately swelling potentially re-opening the surgical implant site. Also, no current tissue expander is re-shapable, reducing their usefulness. Phase I research showed that hydrogels could be generated which had the desirable properties of reshapability, 2-3 weeks of the lag time prior to expansion, and post-degradation high mechanical strength. These properties could also be controlled by changing chemical composition of the hydrogels. Phase II research will focus on combining these desired properties into a few optimized prototypes and subsequently testing of these prototypes for safety and efficacy in animal models to generate tissue expanders ready for clinical trials. Specific Aim 1 is to synthesize more delayed swelling hydrogels each possessing three requirements ideal for tissue expanders. Akina has already identified one hydrogel prototype with desired properties. Six optimized prototypes will be selected to carry forward to the next stages. Specific Aim 2 is to examine the efficacy of selected tissue expanders in the rat model. This will screen the six prototypes down to the one which is most effective as a tissue expander. Specific Aim 3 is to examine the toxicity of the tissue expander identified in Aim 2 and test its efficacy in the dog model. Safety of this prototype will be determined using ISO 10993 testing to ensure the hydrogels are non-toxic and biocompatible. An intra-oral dog model will be utilized to determine the efficacy of the hydrogel prototype in a setting representative of dental use. Specific Aim 4 is to produce a delayed swelling tissue expander ready for clinical studies. The hydrogel prototype that has been shown to be safe and effective in the animal studies will be used to prepare application to the Food and Drug Administration (FDA) for approval of clinical studies. Successful completion of this Phase II study will generate novel, delayed-swelling, hydrogel based, tissue expanders which do not suffer the drawbacks of current tissue expansion technologies. These tissue expanders will be easily re-shapable, have delayed expansion, have good post-degradation strength, and be shown to be safe and effective in animal models. Akina's delayed swelling tissue expander will provide substantial advantages over the current tissue expander on the market, and thus immediate impact to the field is expected.

Public Health Relevance:
This Phase II SBIR project will generate re-shapable, delayed-expansion, hydrogel-based tissue expanders for use in dental and other reconstructive surgeries. These tissue expanders will overcome problems associated with current technology, such as eliminating exterior equipment and allowing custom fitting of the expander to the tissue by the surgeon. This technology will reduce the incidence of morbidity associated with this surgery, thus promoting general public health.

Public Health Relevance:
This Public Health Relevance is not available.

Thesaurus Terms:
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