A light-sensitive hydrogel for ingestible medical devices has recently been developed by MIT researchers, Fig. 1. Integrated with medical devices, doctors can insert those tiny systems into the human body to treat, diagnose or monitor disorders. Once those devices are no longer needed, they can then be dissolved inside the body by exposing them to light from an ingestible light-emitting-diode or LED.
Earlier, another MIT research group developed “a rubbery material, mostly composed of water, and designed to bond strongly to surfaces such as gold titanium, aluminum, silicon, glass, and ceramic.” They also called this material hydrogel, but this research centered on external human body application.
It was described as a “water-based Band-Aid that senses temperature, lights up, and delivers medicine to the skin,” according to published reports. Researchers said that it can also be used externally because they claim it has certain characteristics that are similar to human skin.
They’re calling it a Band-Aid because this stretchable and flexible material can be applied to various parts of the body, like an elbow or a knee. A key advantage is the hydrogel keeps embedded electronics functional, robust, and intact. This is largely due to the fact it has good bonding strength like gold, titanium, aluminum, or silica gel, which are normally used in conventional PCB assembly.
These developments tell you that medical electronics products are taking a new direction and into completely new dimensions. Plus, it tells medical electronics OEMs to think about putting products like these on their drawing boards.
From a PCB assembly and manufacturing point of view, there are a number of factors medical OEMs should consider when engaging with their EMS provider partners. Check out our SMT007 column on soft electronics to get a good understanding. In the meantime, here are some tips and hints to get you started.
- Talk about how chemical compounds will interact with one another in a given application.
- Discuss types of microelectronics circuity that’ll be embedded in the hydrogel.
- Assure the hydrogel’s thickness is sufficient to implant such devices as flip chips, die attached or micro-electromechanical systems (MEMS) into the hydrogel.
- Mutually scrutinize and analyze the usual concepts of PCB conventional and microelectronics assembly and how they apply to these new medical devices.
- Discuss how to process different aspects of electronics into this new jelly-like material.
- Talk about the circuit board, itself, and whether or not it’ll have similarities to a conventional flex circuit or if a completely new circuit board is required.
This is a whole new ballgame where you have different chemical and mechanical properties associated with new “soft electronics materials.” Plus, there’s also the issue of device selection and associated questions pertaining to LED brightness, its heat, and thermal expansion. And perhaps there may be new types of electronics devices that are more conducive for interacting with hydrogel material.