Supported by the National Natural Science Foundation of China (Grant Nos. 52321006 and T2394484), the team led by Prof. Yanlin Song at the Institute of Chemistry, Chinese Academy of Sciences, with collaborators, has proposed a nondestructive transfer strategy for ultrathin films, termed “drop-printing”. This study, titled “Drop-printing with dynamic stress release for conformal wrap of bioelectronic interfaces,” was published in Science on September 12, 2025 (https://www.science.org/doi/10.1126/science.adw6854).

Technologies such as brain-computer interfaces, neural rehabilitation, and wearable electronics require precise, nondestructive transfer of ultrathin electronic devices onto complex biological surfaces. However, traditional methods easily cause stress concentrations, leading to damage to thin-film devices. Effectively regulating stress during the transfer of flexible electronic devices has become a key scientific challenge.

To address this issue, the research team developed a drop-printing method that used a liquid droplet to pick up and transfer ultrathin devices while forming a lubricating liquid interfacial layer between the device and the target surface. This interfacial layer not only assists conformal contact via capillarity action but also allows film sliding to dynamically release stress, preventing device damage. By adding trace amounts of polymer to the droplet, the team was able to control the behavior of the three-phase contact line, markedly improving transfer accuracy. The method enables nondestructive transfer of micro-/nanometer-thick metallic, silicon, and other ultrathin devices onto complex structures. In addition, tuning droplet composition can also achieve cell films transfer and bioadhesion. In animal experiments, the researchers successfully wrapped a 2-μm-thick silicon heterojunction device onto nerves and brains, achieving high-spatiotemporal-resolution, light-controlled neuromodulation.

This study introduces a nondestructive transfer approach for ultrathin films, broadening the application of flexible electronics and supporting advances in brain-computer interfaces, wearable devices, and biomanufacturing.

Figure. Drop-printing for stress-free, conformal wrapping of thin-film devices. (a) Schematic of the drop-printing process; (b) Dynamic stress release within the film; (c) Final stress distribution in the film; (d-e) Ultrathin Au film wrapped to Paramecium; (f) Graphene nanosheets wrapped to an optical fiber; (g) Silicon film wrapped to a glass tube.