Novel Polymeric Bio-materials

In present era, polymers are leading materials in every aspect from commodity to aerospace. In medical devices polymers are gaining importance day by day. With the advent of new materials such as 2D polymers[1] (Graphene, MoS2, Borophene) the scope is more widened and open. Due to exceptional chemical resistance, good biocompatibility, lightweight and tunable mechanical properties bio-polymers are observing their continuous growth in the field of medical devices. With the addition of smart properties such as temperature responsiveness, pressure responsiveness the application and end-use of bio-polymers can be analysed more accurately and precisely.

Polymeric materials are used due to relatively easy processing and biocompatible nature as well as their vast range of mechanical, physical, electrical, chemical, and thermal behaviours when combined with different materials as nanocomposites. Different synthetic polymeric materials such as polyvinylidene fluoride (PVDF), Polyethylene (PE), Polypropylene (PP), Polydimethylsiloxane (Silicones), Polyethylene Terephthalate (PET), Polyamide, Polytetrafluoroethylene (PTFE), Polyimide, Polyurethane, liquid crystalline polymers and polymer nanocomposites are used as biomaterials in medical device field.

Table1- Polymer materials used in balloon catheters and their properties[2]

Medical Device performance

The performance of medical device is complicated as there are various contributing and related factors, including device design, material selection, structural properties, manufacturing conditions of device and clinical issues[3]. These factors contribute to a multidimensional problem that often requires several iterations in device design with a proper feedback that relies on evaluation of device. 

Fig 1- Parameters affecting medical devices performance

Electronic conductive polymer (ECP)[4]

Conducting polymers are organic polymers that conducts electricity. They can provide high electrical conductivity but do not show similar mechanical properties to other commercially available polymers. Conducting properties can be fine-tuned using the methods of synthesis and by facilitating dispersion techniques. These polymers combine the two most important properties; electrical properties of metals with advantages properties of polymers such as lightweight, chemical resistance and lower cost. With the application of these polymers ranging from space, aeronautics, medical to electricals; these materials are considered as the wonder material for 21st century. Common electronically conductive polymers are Polyaniline, Poly (p-phenylene vinylene), Polypyrrole, Polyacetylene, Polyfulvenes, Polythiophene.

Fig 2- Conducting Polymers[5]

 Smart Catheters- Various research methodologies have been proposed on the development of controllable and smart catheters in the biomedical field. Electronic conductive polymers (ECP) actuators are one of the most suitable systems due to their biocompatibility, low operating potential (± 2V) with minimal deformation (2%). Smart catheters should have two properties: strong deformations tip in order to reach and enough rigid middle part for getting forward in the curvy and twisty vessels network.

Electromechanical Actuators- Polymer based actuators are novel and advanced technology. Functioning of actuators is done by using changes in dimension of conductive polymer, changing in total volume of conducting polymer electrode, electrolyte and counter electrode. Method of doping (deposition)and de-doping(removal) is same as re-chargeable batteries. 

Polymer Nanocomposites[6] – Polymer nanocomposites are defined as a mixture of two or more phase separated materials, where dispersed phase is in nanoscale and polymeric material will be in major phase. Nanoscale materials are those materials which have least one relevant length scale within the range of nanometres. Polymer nanocomposites which are most widely used in catheters developments are consist of polymers with nanomaterials such as Montmorillonite, graphene, clay etc.

Fig 3- Graphene polymer nanocomposites[7]

 Polymer Nanocomposites angioplasty balloon- The inflatable medical balloons include balloon walls that are reinforced with graphene. The balloon walls can include any number of layers and one or more of the layers may include graphene. By incorporating nanomaterial, the mechanical properties of angioplasty balloon will be increased by great extent for example burst pressure can increase by 2 or more folds, wall strength and rupture strength are also increased[8]. With addition of nanocomposites higher mechanical properties can be achieved lower wall thickness. We can also tune the properties of angioplasty balloon with the loading amount.

Conclusion- Polymer biomaterials are leading the medical industry from front. Due to their excellent chemical resistant and with the arise of smart polymers the impact of polymer biomaterials in medical device industry is significant. ECP are attracting the limelight due to their controlled and smart behaviour, shape memory polymers are gaining importance due to their ability to regain shape and in last polymer nanocomposites providing great mechanical strength. With the application of advanced technology, we can achieve new heights in medical device such as controllable devices based of temperature, atmosphere, pressure and several other conditions. Sky is the limit for polymers in medical field.

 References-

[1]     C. G. Navarro and F. Zamora, “Nanoscale,” no. July 2015, 2011.

[2]     “Polymeric Biomaterials for Medical Implants & Devices,” 2016.

[3]     L. Pruitt and J. Furmanski, “Polymeric Biomaterials for Load - bearing Medical Devices,” no. September, 2009.

[4]     S. Sewa, K. Onishi, K. Oguro, K. Asaka, W. Taki, and N. Toma, “The Development for Polymer Actuator Active Catheter System,” vol. 7, pp. 115–123, 2001.

[5]     H. Types et al., “Conductive polymer,” 1980.

[6]     K. Müller et al., “Review on the Processing and Properties of Polymer Nanocomposites and Nanocoatings and Their Applications in the Packaging , Automotive and Solar Energy Fields,” 2017.

[7]     C. Mechanisms, “Thermal Conductivity of Graphene-Polymer,” pp. 1–17, 2017.

[8]     P. Classification, “( 12 ) Patent Application Publication ( 10 ) Pub . No .: US 2015 / 0352335 A1,” vol. 1, no. 19, 2015.

“Any sufficiently advanced technology is indistinguishable from magic.” Sir Arthur Charles Clarke