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In this work, we utilize a recently developed microbubbling process to generate controlled protein (bovine serum albumin, BSA) coated bubbles and then manipulate these to fabricate a variety of structures suitable for several generic biomedical applications, tissue engineering, and biosensor coatings. Using BSA solutions with varying concentrations (20, 25, and 30 wt %) and cross-linking (terephthaloyl chloride) mechanisms, structures were fabricated including porous thin films with variable pore sizes and thickness (partially cross-linked coupled to bubble breakdown), scaffolds with variable pore morphologies (fully cross-linked), and coated bubbles (no cross-linking), which can be used as stand-alone delivery devices and contrast agents. The movement of typical biosensor chemicals (catechol and hydrogen peroxide) across appropriate film structures was studied. The potential of formed scaffold structures for tissue engineering applications was demonstrated using mouse cell lines (L929). In addition to low cost, providing uniform structure generation and high output, the size of the bubbles can easily be controlled by adjusting simplistic processing parameters. The combination of robust processing and chemical modification to uniform macromolecule bubbles can be utilized as a competing, yet novel, tool with current technologies and processes in advancing the biomaterials and biomedical engineering remits.

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Amphiphilic block copolymers are widely used in science owing to their versatile properties. In this study, amphiphilic block copolymer poly(lactic- co-glycolic acid)- block-poly(ethylene glycol) (PLGA- b-PEG) was used to create microdroplets in a T-junction microfluidic device with a well-defined geometry. To compare interfacial characteristics of microdroplets, dichloromethane (DCM) and chloroform were used to prepare PLGA- b-PEG solution as an oil phase. In the T-junction device, water and oil phases were manipulated at variable flow rates from 50 to 300 μL/min by increments of 50 μL/min. Fabricated microdroplets were directly collected on a glass slide. After a drying period, porous two-dimensional and three-dimensional structures were obtained as honeycomb-like structure. Pore sizes were increased according to increased water/oil flow rate for both DCM and chloroform solutions. Also, it was shown that increasing polymer concentration decreased the pore size of honeycomb-like structures at a constant water/oil flow rate (50:50 μL/min). Additionally, PLGA- b-PEG nanoparticles were also obtained on the struts of honeycomb-like structures according to the water solubility, volatility, and viscosity properties of oil phases, by the aid of Marangoni flow. The resulting structures have a great potential to be used in biomedical applications, especially in drug delivery-related studies, with nanoparticle forming ability and cellular responses in different surface morphologies.

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