Smart Polymer-based Microdevices for Biomedical Applications
Among the challenges listed to build autonomous micro robotic agents, the ability to interact with the environment represent a possible way to enlarge the potential and the use of the final devices. A possible way to approach the problem is to include into the fabrication methods materials that naturally possess this ability, or can be easily tailored in that sense.
Hydrogels, tri-dimensional polymeric networks have been shown to be useful for a big range of biomedical applications, including drug delivery, ophthalmology, tissue engineering, sensor design, and micro fluidics (Peppas et al. Adv. Drug. Del. Rev. 61, 1391-1401, 2009). Moreover some of them show a behavior dependent on the environmental conditions, like a change in temperature or pH, or can be easily modified in that sense.
Considering their potential, our goal is to build a hydrogel based fully autonomous untethered platform which possesses the following characteristics:
- It can be propelled by magnetic field gradients or oscillating magnetic fields.
- It responds to environmental conditions.
- It is able to perform complex tasks like cell manipulation or controlled drug delivery.
Fabrication of Smart Microrobots by Electrodeposition
It is well known that temperature and pH oscillations are related to local or global inflammations and diseases. These small changes in the environment can be exploited by microrobots to perform a simple action like drug delivery in a smart way. Stimuli responsive materials can be incorporated into microdevices by electrodeposition. This technique is based on the exploitation of an electric signal to assemble conductive molecules and particles of different nature on conductive substrates of every shape and dimension. The control of the deposition parameters and conditions allow the formation of layers with different characteristics, that can be used to incorporate and release drugs in a controlled and desired way.Our goal is to exploit this technique and provide complex platforms to magnetic micro robots for targeted actions, in zones of the body that are currently hard to be reached with conventional drugs or interventions.
Fabrication of Smart Microrobots by Standard Photolithography
Photolitography represents a flexible and powerful method to create 2D and 3D microstructures of different materials. 3D structures of hydrogels and hydrogel composites ( nanoparticles enriched networks) can be produced with this technique by mixing the polymer solutions with photoinitiators that respond to UV light. Complex 3D devices able to move and respond local stimuli or to be triggered by our control and manipulation systems can be created in a way similar to origami, by exploiting the induced bending on mechanically heterogeneous hydrogel layers.
Such platforms have a potential use in a variety of minimally invasive medical operations, such as drug and cell on demand delivery, hyperthermia, transport and peripheral angioplasty.