| Summary: |
Prosthetic devices are used to replace part of the limb, after amputation, because of trauma or disease. Prosthesis are custom made medical devices, according to the EU Directive (42/93/EC), and its intended use is to compensate for impairments and mobility limitation, allowing a similar to counter lateral, comfortable and safe gait to the amputee. The results of the non-adequate fit of the prosthesis are poor static and dynamic weight support, gait deviations and non efficient gait. As a consequence, in most cases, there is overload of the non amputated side and high energy consumption. In extreme situations the amputee stops using the device. The production of the prosthesis, and its fit to the amputee, implies alignment of the socket and structure, referring to defined parameters. These assessments are done using qualitative methods, which are not reliable and are based on the experience of the practitioner.
Taking this as a start point, the present project relates to the development of a sensors network device for mapping the pressure fields at the prosthesis/limb interface, especially artificial lower limbs. In basic terms, the present project consists on the design and implementation of a sensor array, developed from piezoelectric (sensitive to dynamic pressure fields) and piezoresistive (measure static and dynamic deformations) smart polymeric materials, such as (poly(vinylidene fluoride) - PVDF and its co-polymers and elastomers or thermoplastics nanocomposites from carbon nanotubes or nanofibres, respectively. These polymeric sensing materials will be spottily functionalized with a PVD conductive thin layer, TiN, in an array-type design, Fig. 1. The all set will have a protective top insulating coating (TiO2), avoiding also electrical short-circuiting between close sensors. The choice of TiN-based compounds is related with their high corrosion, impact and wear resistances, together with good chemical, thermal and mechanical stability. Silver will  |
Summary
Prosthetic devices are used to replace part of the limb, after amputation, because of trauma or disease. Prosthesis are custom made medical devices, according to the EU Directive (42/93/EC), and its intended use is to compensate for impairments and mobility limitation, allowing a similar to counter lateral, comfortable and safe gait to the amputee. The results of the non-adequate fit of the prosthesis are poor static and dynamic weight support, gait deviations and non efficient gait. As a consequence, in most cases, there is overload of the non amputated side and high energy consumption. In extreme situations the amputee stops using the device. The production of the prosthesis, and its fit to the amputee, implies alignment of the socket and structure, referring to defined parameters. These assessments are done using qualitative methods, which are not reliable and are based on the experience of the practitioner.
Taking this as a start point, the present project relates to the development of a sensors network device for mapping the pressure fields at the prosthesis/limb interface, especially artificial lower limbs. In basic terms, the present project consists on the design and implementation of a sensor array, developed from piezoelectric (sensitive to dynamic pressure fields) and piezoresistive (measure static and dynamic deformations) smart polymeric materials, such as (poly(vinylidene fluoride) - PVDF and its co-polymers and elastomers or thermoplastics nanocomposites from carbon nanotubes or nanofibres, respectively. These polymeric sensing materials will be spottily functionalized with a PVD conductive thin layer, TiN, in an array-type design, Fig. 1. The all set will have a protective top insulating coating (TiO2), avoiding also electrical short-circuiting between close sensors. The choice of TiN-based compounds is related with their high corrosion, impact and wear resistances, together with good chemical, thermal and mechanical stability. Silver will be added as nanoclusters dispersed in the TiN-base matrix or in a multilayer-like approach (TiN/Ag). The addition of silver will be carried out to reduce the brittle-like character of TiN (reduction of Young's modulus) and thus avoiding problems of film detachment and conduction failures when the sensors bend of wrinkle (one of the major problems in the available sensor systems). Moreover, the anti-bactericide activity of silver will be also used to avoid the problems of fungus and bacterial activity that might develop due to normal patients' activity (sweating, etc.). The anti- bactericide character of silver will be also used in the insulating protective top layer, TiO2. The all set will insure a multifunctional character to the sensors, providing at the same time the signals reading, and both mechanical and biological protection. The paper-thin spottily coated piezoelectric/piezoresistive sensor device, will provide highresolution, and will be optimized with sets of stripe-type bands or squared/rectangular bands placed in the socket surface that is in contact with the stump. |