Researchers in the US have fabricated a flexible and wearable wound dressing that can help control the temporal and spatial release of different drugs. This could help fight the infection of damaged tissues and stimulate the healing process (Adv. Funct. Mater. doi: 10.1002/adfm.201702399).
The patch consists of a microcontroller and multiple fibres coated in a gel containing a drug agent. By sending a small electrical voltage, the microcontroller causes the fibres to heat up and release the agents. Each fibre can support a different cargo, which enables the delivery of multiple antibacterial drugs at the same time, while the microcontroller determines the dose and rate of distribution.
The study focusses on the engineering of the bandage and highlights the different steps undertaken in its manufacturing. Ali Tamayol and his colleagues at Brigham and Women’s Hospitalfirst ensured that the drug release rate and its temporal profile could be regulated via the microcontroller.
They realised that the more fibres were activated, the larger the administered dose. Higher temperatures, up to 45°C, caused a faster drug release and did not hinder the healing process.
Fighting infection and stimulating recovery
The researchers subsequently tested the patch in vitro by inserting the fibres into cell cultures containing bacteria. To showcase the patch’s potential to both fight infection and stimulate healing, they considered three settings: a control group where the fibres didn’t contain any drug; one where the patch contained an antibiotic; and a group with a patch that featured both the antibiotic and a vascular endothelial growth factor (VEGF).
The antibiotic eradicated the bacteria in the latter two cultures, while the VEGF helped capillaries to form. Conversely, the majority of the cells in the control culture were dead.
Three wounded mice where then given a patch loaded with VEGF while three others were administered dry patches. The results revealed that the animals treated with the manufactured bandage regrew three times as many blood-rich cells as the control ones.
An economic need for such bandages
Building from the group’s previous work, which showed that engineered textiles could monitor physiological informationsuch as glucose level and pH, this new platform has demonstrated the ability to release multiple drugs in a customized fashion. The new patch also has braiding and weaving that can be modified to fit different circumstances. It offers a personalized and multi-purpose alternative to a standard bandage.
This approach could be particularly useful to treat chronic wounds in which the healing process is impaired. For example, diabetic foot ulcers, a condition that can lead to amputation is a prime candidate. Foot ulcers represent an estimated expenditure of approximately $116 billion in direct medical costs and currently affect 25 million Americans – with the figure expected to double by 2050. This all-encompassing patch would hence help alleviate an economic burden. The bandage could be used to prevent infection of battlefield injuries and help trigger tissue recovery.