Tissue sealants of a liquid based formulation are widely studied in biomedical research with many starting to gain FDA approval. To date, little investigation has been put toward methods of application for tissue sealant materials, more specifically a powder based formulation. The focus of this research was to develop and prototype a powder spray device capable of administering powder based formulations with a long-term goal of integrating the device within the clinical setting. Powders can be administered in a variety of dry forms. These forms can range from non-homogenous nanoscale particles to homogeneous micro and nano-scale spheres. Incorporation of therapeutics within the powder makes this method of application favorable for the prevention or maintenance of disease. Pneumatic conveying is the transport of granulated solids using gas and is the principal basis from which the powder spray gun was designed. Fluidization aids were added to the device in order to increase powder flow properties. Analysis of spray field, spray rate, characterization of powder and ex-vivo testing was performed. All results suggest that the powder spray device is applicable for the deposition of powder based tissue sealants in a clinical setting.

Lung diseases, cancers, and trauma can result in injury to the connective tissue lining the lung, i.e., the pleura. Pleural injuries lead to pneumothoraxes or pleural effusions, i.e., air or fluid leaking out of the lung respectively, and potential lung collapse - an immediately life threatening condition. While several bioengineered soft tissue sealants exist on the market, there is only one sealant FDA-approved for use in pulmonary surgery. In addition, very limited techniques are presented in the literature for characterizing the burst properties of hydrogel tissue sealants. For my thesis, I proposed to develop a protocol for characterizing the burst properties of hydrogel sealants using a novel burst pressure test chamber. I further proposed a novel combination of oxidation and methacrylation reactions of alginate for tissue sealant applications, with a particular focus on developing a pulmonary sealant. The proposed research objectives are: 1) To develop protocol for testing hydrogel sealants for soft tissue applications; 2) To verify alginate as a potential for tissue sealant applications; and 3) To optimize an alginate hydrogel sealant and perform ex vivo analysis for a pleural sealant application. Alginate materials with varying degrees of oxidation and methacrylation were synthesized and characterized. Oscillatory rheometry was used to characterize material properties such as viscosity, hydrogel gelation kinetics, and complex moduli. Burst pressure measurements properties and failure mechanisms, i.e. delamination or material failure, were collected for a liquid and dry-state application. Preliminary ex vivo mouse lung model testing demonstrated that methacrylated alginate hydrogels are able to withstand physiological pressures associated with breathing, and failure occurs within the hydrogel for adhesive alginate-based tissue sealants.