In-situ formation of dual-gradient hydrogels through microfluidic mixing and co-extrusion for constructing an engineered antibacterial platform

The explosive release of antibiotics caused by drug delivery hydrogels can potentially cause cell damage. To balance the antibacterial activity and cytotoxicity of drug-loaded hydrogels, we present a double gradient hydrogel (PCHH) using microfluidic mixing co-extrusion technology. The gradient structure of the hydrogel can be controlled by adjusting the distribution of sodium alginate and amikacin. This allows for different swelling and drug release behaviors which can maintain a wet environment and optimize drug release behaviors. Amikacin is released at a rate of 50 % within 24 h and achieves sustained and uniform drug release in the later stages. The antibacterial properties displays that the synergistic antibacterial activity between amikacin and carbon dots reduces the dosage of amikacin and decreases bacterial resistance. This design principle offers new opportunities for hydrogels engineered with microfluidic chemistry, which can be applied in tissue engineering, soft robotics, and active medical implants.