Implantable, wireless, self-fixing thermal sensors for continuous measurements of microvascular blood flow in flaps and organ grafts

Di Lu, Shupeng Li, Quansan Yang, Hany M. Arafa, Yameng Xu, Ying Yan, Diana Ostojich, Wubin Bai, Hexia Guo, Changsheng Wu, Shuo Li, Lauren Jacobson, Amanda M. Westman, Matthew R. MacEwan, Yonggang Huang*, Mitchell Pet, John A. Rogers

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Vascular pedicle thrombosis after free flap transfer or solid organ transplantation surgeries can lead to flap necrosis, organ loss requiring re-transplantation, or even death. Although implantable flow sensors can provide early warning of malperfusion and facilitate operative salvage, measurements performed with existing technologies often depend on extrinsic conditions such as mounting methods and environmental fluctuations. Furthermore, the mechanisms for fixing such probes to vascular or skeletal structures may disrupt the normal blood flow or cause unnecessary tissue damage. Requirements for wired connections to benchtop readout systems also increase costs, complicate clinical care and constrain movements of the patient. Here, we report a wireless, miniaturized flow sensing system that exploits sub-millimeter scale, multi-nodal thermal probes, with biodegradable barbs that secure the probes to the surrounding tissues in a manner that facilitates removal after a period of use. These smartphone-readable devices, together with experimentally validated analytical models of the thermal transport physics, enable reliable, accurate flow sensing in ways that are largely immune to variations in temperature and mechanical perturbations. In vivo demonstrations of this technology in porcine myocutaneous flap and kidney malperfusion models highlight the essential capabilities in microsurgical and transplantation-related biomedical application scenarios.

Original languageEnglish (US)
Article number114145
JournalBiosensors and Bioelectronics
StatePublished - Jun 15 2022


  • Biodegradable materials
  • Flow sensing
  • Heat convection
  • Implantable wireless devices
  • Thrombosis diagnosis

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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