Agar/gelatin bilayer gel matrix fabricated by simple thermo-responsive sol-gel transition method

•A novel and simple method is developed to produce an agar/gelatin bilayer gel matrix.•The method is based on thermo-responsive sol-gel transitions of agar and gelatin.•The bilayer gel matrix can be employed to separately load various materials.•The bilayer gel matrix enables stepwise release under the control of thermal stimuli.•This bilayer gel matrix is a promising candidate for various biomedical applications.

We present a simple and environmentally-friendly method to generate an agar/gelatin bilayer gel matrix for further biomedical applications. In this method, the thermally responsive sol-gel transitions of agar and gelatin combined with the different transition temperatures are exquisitely employed to fabricate the agar/gelatin bilayer gel matrix and achieve separate loading for various materials (e.g., drugs, fluorescent materials, and nanoparticles). Importantly, the resulting bilayer gel matrix provides two different biopolymer environments (a polysaccharide environment vs a protein environment) with a well-defined border, which allows the loaded materials in different layers to retain their original properties (e.g., magnetism and fluorescence) and reduce mutual interference. In addition, the loaded materials in the bilayer gel matrix exhibit an interesting release behavior under the control of thermal stimuli. Consequently, the resulting agar/gelatin bilayer gel matrix is a promising candidate for biomedical applications in drug delivery, controlled release, fluorescence labeling, and bio-imaging.

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