Mohammad Reza Abidian, Ph.D. - US grants

This award by the Biomaterials program in the Division of Materials Research to Materials Research Society (MRS) provides partial funding for the 2013 Fall MRS Meeting Symposium titled "Integration of Biomaterials with Organic Electronics." This Symposium will be an integrated forum for a discussion of the most recent advances in Biomaterials, Electronic Materials and their engineering applications, and aims to integrate all three areas through interactions. In addition, this symposium will consist of oral and poster presentations with a focus on synergistic integration of biomaterials and organic materials with neural engineering and cellular phenomena to address unmet needs. The invited speakers are widely recognized as leaders in their fields and will deliver focused lectures with broad scientific appeal. Special attention will be devoted to the development of a diverse program including the participation of under-represented groups, international participation, and broad interdisciplinarity. The partial funding of this Symposium by this award will support the participation of undergraduate and graduate students at this MRS meeting.

The scientific broader impact of this symposium will be to inform investigators at all levels about the unmet needs and emerging opportunities in the areas of research at the interface between non-conventional electronics and biomedical applications. The symposium provides a forum in which materials researchers including students working in the areas of biomaterials and organic electronic materials will report on recent advances in the field. The funds requested from NSF will support the attendance of both undergraduate and graduate students, who will make oral and poster presentations at the Symposium, and will be interacting with leaders in their fields during the meeting.

PI: Abidian, Mohammad Reza
Proposal Number: 1431799
Institution: Materials Research Society
Title: Advanced Multifunctional Biomaterials for Neuroprosthetic Interfaces (Revision) in San Francisco, CA, on April 21-25, 2014

This proposal seeks support primarily for students and young investigators from US institutions to attend the Advanced Multifunctional Biomaterials for Neuroprosthetic Interfaces Symposium that will be held at the 2014 Materials Research Society meeting, San Francisco, CA, April 21-25, 2014. The main theme of this interdisciplinary symposium is the study and application of biomaterials that interface with biological systems, especially neural cells and tissues. Session topics will highlight the latest efforts to achieve safe and effective strategies to communicate with neurons. As such, the scientific content and timing of the symposium are both appropriate. The list of confirmed invited speakers includes prominent investigators in their respective areas of research.

Neural prostheses are critical in treating or assisting people with disabilities of neural function. In spite of recent advances in neural interface technology, engineering stable and reliable electronic-neural tissue interfaces for long-term functionality remains a critical issue. The challenge for material science is to design and develop advanced multifunctional biomaterials to safely integrate with neural tissue with minimal biological response. Furthermore, the implant should match the mechanical properties of surrounding tissue to prevent injury due to micromotion and allow for adequate exchange of nutrients and waste so that the surrounding tissue remains healthy. This symposium will focus on the latest advances in biomaterials to control/engineer neuron-electronic interfaces to produce stable and functional implants with greater longevity than what is possible today.

DESCRIPTION: This application aims to provide a mechanistic understanding of the effect of gradients of physical and chemical guidance cues (GCs), individually and combinatory, on guidance and modulation of axonal growth. The proposed study will specifically answer to questions whether: (1) immediate turning of growth cone depends on the difference between the concentration gradients on the left- and right-hand sides of the growth cone; (2) immediate and biased turning and growth-rate modulation work together to guide axons towards their targets; (3) integration of gradients of multiple cues can provide a precise regulation mechanism for axonal guidance. Axons are guided along specific pathways by gradients of attractive and repulsive cues in their extracellular environment. To understand the effect of gradients of guidance cues individually or in combination on growth cone turning and growth rate modulation, the development of platforms that are capable of producing precisely controlled shape gradients of guidance cues is essential. I propose to develop an inexpensive and high- throughput technology that is capable of providing precise, reproducible, and arbitrarily shaped gradients of physical and biochemical cues to direct and modulate axonal growth. For these studies, we will first fabricate aligned nanotubes of conducting polymer loaded with nerve growth factor on micro-fabricated electrode arrays. To release the entrapped nerve growth factor, we will actuate these nanotubes by applying electrical voltages. By varying the actuating voltage across the electrode array, we will create precisely controlled gradients of released nerve growth factor on these microelectrodes. Next, we will generate gradients of substrate-bound molecules, in this case laminin, on conducting polymer nanotubes across the electrode array. Inclusion of laminin on the nanotubes will be achieved by using this protein as a dopant during electropolymerization of conducting polymer. We will employ different concentrations of laminin on individual electrode sites to achieve the desired gradient profile. To generate gradients of surface topography, we will create gradients in diameter and surface roughness of aligned conducting polymer nanotubes on the micro-fabricated electrode arrays. We will modulate (a) the diameter of conducting polymer nanotubes by varying the time of electrochemical polymerization of conducting polymer, and (b) the surface roughness of conducting polymer nanotubes by varying the current density applied during electrodeposition. Finally, we will develop a 3D conduit consisting of a PDMS guidance channel that contains nanostructured conducting polymers that provide (i) physical and biochemical growth cues, and (ii) low impedance electrodes to monitor axonal growth by electrophysiological recording along the regeneration pathway. This multifunctional conduit will be tested in vitro and vivo to determine the effect of gradient of multiple guidance cues on axonal growth direction and rate. The results of these studies may significantly impact society by paving the way for a solution to the major clinical problem of axon regeneration and guidance.