ABSTRACT
Hydrogels are pivotal in tissue engineering, regenerative medicine, and drug delivery applications. Existing hydrogel platforms are not easily customizable and often lack precise programmability, making them less suited for 3D tissue culture and programming of cells. DNA molecules stand out among other promising biomaterials due to their unparalleled precision, programmability, and customization. In this study, we introduced a palette of novel cellular scaffolding platforms made of pure DNA-based hydrogel systems while improving the shortcomings of the existing platforms. We showed a quick and easy one step synthesis of DNA hydrogels using thermal annealing based on sequence specific hybridization strategy. We also demonstrated the formation of multi-armed branched supramolecular scaffolds with custom mechanical stiffness, porosity, and network density by increasing or decreasing the number of branching arms. These mechanically tuneable DNA hydrogels proved to be a suitable suitable platform for modulating the physiological processes of retinal pigment epithelial cells (RPE1). In-vitro studies showed dynamic changes at multiple levels, ranging from a change in morphology to protein expression patterns, enhanced membrane traffic, and proliferation. The soft DNA hydrogels explored here are mechanically compliant and pliable, thus excellently suited for applications in cellular programming and reprogramming. This research lays the groundwork for developing a DNA hydrogel system with a higher dynamic range of stiffness, which will open exciting avenues for tissue engineering and beyond.
ABSTRACT
In this work, κ-carrageenan and olive oil at different oil to κ-carrageenan ratios (OCR) are homogenized to create emulsion gels. Interestingly, confocal imaging shows that the oil droplets are stabilized in the κ-carrageenan-structured gel matrix without using any surfactants. Rheological studies show that the oil droplets enhanced the oscillatory yield stress and the maximum printable height of the emulsion gels. The creation of the emulsion gels with an OCR of 1:9-3:7 led to an improvement in the structural integrity of extrusion printed structures. The emulsion gel with an OCR of 3:7 efficiently encapsulates vitamin C in the aqueous phase and curcumin in the hydrophobic oil phase, enabling the extrusion 3D printing of tablets with varying surface area to volume (SA/V) ratios. The release of vitamin C and curcumin is influenced by the preparation method of printing versus casting and the SA/V ratio of the tablets. The hollow cylinder with the highest SA/V ratio was observed to have the highest vitamin C release, whereas for curcumin, the printed tablets had a higher release compared to the cast tablet. Additionally, through rheo-dissolution experiments, we observe a lower modulus and higher vitamin C release from the 3D-printed disc versus the higher modulus and lower vitamin C release from the cast disc tablet.