Self powering implanted devices have been the main goal for most miniature devices. Harvesting bioenergy is a remarkable method that can utilize a natural energy such as heart beat by convert ing the mechanical energy into electric power that can charge or even power implanted devices such as pacemaker. This project is demonstrated the novel idea of using dual layers Nano-scale film of polyvinyildin defloride (PVDF) and Graphene composite laying on each others that are e m b e d d e d i n t o s e l f c u r l i n g biocompatible silicone cuff. Each PVDF\ Graphene layer which has dimension Wp=8mm,Lp=28mm,and Hp=17µm. Additionally, the Nano fibers film can be attached to vibrating transmitting plate for harvesting heart beat energy and encapsulating the whole device with a biocompatible material as PDMS.

   

   

   

Nazar Fadhil1, Dleer Saber1, Paris Cox3, Kripa Vanashi3 and Prabir Patra1,2

1Departmentof Biomedical Engineering 2 Department of Mechanical Engineering

1,2University of Bridgeport, Bridgeport, CT 06604 3Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139

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Far field electrospinning (FFES) experiments were conducted to obtain PVDF Nano fibers with Graphene composites . The fibers were collected randomly with controlled parameters.

The PVDF\Graphene Nano fibers composite exhibited less non polar of α-phase and enhancing formation of β-crystalline for the PVDF compared to the absolute PVDF Nano fibers as shown by the X-ray diffraction in Fig.3 Multilayer of PVDF/ Graphene film can be used and the total harvested power is calculated with the equation as shown below The average power is inversely proportional to the PVDF thickness with assuming resistance of mock artery is constant at 125MΩ. At PVDF thickness of 17µm, the corresponding average power of 30nwatt is calculated as in Fig.4 Table below shows an obvious difference of harnessed power when the PVDF\ Graphene film thickness enhanced to 17µm. Power is calculated theoretically and approximately is twice order than achieved in vitro. The produced Nano fibers film is embedded into silicon 0.30 cm3 cuff .The device is calculated to get average peak voltage of 3.8 v

    The cuff was placed around the mock artery connected to a high input impedance voltmeter. The tube was compressed and relaxed to generate time

varying wave form correspond to blood pressure.                .  

   

 

 

 

 

 

 

 

 

 

Ø  Implanted devices such as internal defibrillator therapy (IDT) and pacemaker are battery powered, PVDF/ Graphene Nano fibers could be utilized to generate an energy by transforming heartbeat to an electric signal as depicted in figure (1).

 

The investigation and analysis are undergoing to estimate the best parameters that can be selected through the experiment in order to enhance the β - crystals formation. PVDF/ Graphene Nano fibers with size of 170nm or less can be grouped together to boot the power output up to three order than conventional one. Furthermore, several experiments must be conducted in vitro to enhance the device affectivity ad reduce external artifacts to assess the validation of assembly. Supper capacitor is another key element would be used in future to enhance electrical storage output .  

 

Battery limitations have been a barrier for long-term device operation due to their limited lifespan and therefor necessitating for periodic replacement. Energy harvesting has the potential to provide self-generating power for implanted medical devises and that would eliminating the need for battery recharging and replacement. This work initiates an evidence of utilizing PVDF Nano scale which can yield significant electric power from internal organs such an artery energy for self depended implanted devices. Nano PVDF / Graphene has tremendous applications due to their capabilities of power harvesting. Nano fibers film used to harnesses mechanical blood pressure from an artery/ harvesting energy or from heart beat by using vibration transmitting plate. Shielding the assembly with PDMS makes a brilliant biocompatible, sustainable device. With the Nano-scale fiber we expect least two orders of magnitude higher power harvesting that result in producing peak voltage of 3.8 and 60nw for double layers enough to charge or power a pacemaker..

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1. J. A. Potkay,K. Brooks, The 2nd International Conference on Bioinformatics and Biomedical Engineering, 2008, ICBBE 2008, 2008, p. 1580. 2. Chengliang Sun, Jian Shi, Dylan J, Bayerl and Xudong Wang, PVDF microbelts for harvesting energy from respiration, Energy Environ. Sci., 2011, 4, 4508 3. Shinichi sato, Akita-shi, Detectection device for detectig heartbeat, respiration and behavior level of small animal, US Patent, 2008 4. Xudong Wang , Piezoelectricnanogenerators—Harvesting ambient mechanical energyatthenanometerscale,Scince Direct, Nano Energy(2012) 1, 13–24.

             

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Ø  Silicon cuff enclosed with dual layer PVDF\ Graphene Nano fiber can convert hemodynamic movement (expansion and contraction) of the aorta artery to corresponding voltage. and deliver to a pacemaker.as shown in Fig (2).

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Design V peak (v) Thickness Power (w) R load (Ω)

Current 2.8 28µm 16nw 125M

Proposed 3.8 17µm 30nw 125M

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Silastic cuff

Artery

Embedded PVDF\ Graphene thin film

Electronic circuit storage

Figure 2: PVDF\Graphene Nano fibers embedded within silastic cuff

Biocompatible electrode PANI

Figure1: PVDF\Graphene Nano fibers attached to a Pacemaker

Figure 4: Relationship between average power with PVDF thickness

Electrospinning machine PVDF Nano fibers film

Figure 3: XRD analysis for PVDF and PVDF\ Graphene composite

Figure 5: PVDF response with applied pulsatile pressure input1