Single-step sound printing of bioadhesive in deep tissue

Bioadhesives and bioadhesion techniques are broadly utilized in clinics and engineering. However, existing bioadhesives, taking the form of liquid, solid, or patches, either require invasive surgical procedure or lack controllability in their delivery process inside the body. Here, we report single-step sound printing (S3P) of bioadhesive, enabling minimally invasive, on-demand, and controllable volumetric printing of biodegradable bioadhesive on deep tissue surfaces in vivo and in situ. Instead of stepwise printing, S3P leverages ultrasound beamforming technique to selectively deposit patterned sound onto tissue surfaces, irreversibly curing the thermosensitive bioadhesive on target position through sonothermal effect by one single step. In contrast to existing ultrasound-based printing techniques relying on super-high sound pressure (35-55 MPa) and/or local temperature (> 70 ℃), S3P prints bioadhesive at the temperature close to that of the body, achieving biosafe and biocompatible sound printing. Moreover, enhanced by sound-induced fluidic streaming, S3P rapidly forms more robust bioadhesion compared with direct thermal curing. We demonstrated the therapeutic efficacy of S3P in minimally invasive gastric perforation repair and locally delivering drugs to tumors. This work explores a new method for delivering bioadhesives inside the body, opening up new chances toward minimally invasive medicine.