Development of Gallium Nitride Based Interfaces

Abstract

Major Goals: Previous work conducted by our lab, and others, showed that photoconductive materials such as GaN and porous Si can be used to stimulate biological cells.20-23 GaN, unlike Si, once exposed to UV light, shows a corresponding prolonged increase in conductivity lasting for many hours, or even days. This phenomenon is known as persistent photoconductivity (PPC). In a previous proof-of-concept work, we showed that this PPC along with chemistry and topography, can not only contribute to the localization of cell in a specific locations, but it can also provide a method for noninvasive in-vitro cellular stimulation. In the referenced work, the properties of persistent photoconductivity (PPC) were utilized to tune the conductivity of a material prior to cellular seeding. It was shown that by exposing GaN semiconductors, PPC materials, to UV-light, this changes not only the surface potential, but also leads to biological changes in intracellular [Ca2+], a key signaling molecule in cellular communication.26 In order to quantify this communication, Fluo-4, a commonly-used dye to quantify [Ca2+]i was used. Previous work only quantified the immediate non-invasive cell stimulation. Though the concept was proven, expanding the applicability of these PPC effects requires greater understanding of materials functionality. Varying the number of charge carriers (dopants) as well as looking at the effect of PPC on chemical functionalization, will provide control knobs for researchers looking to alter cell behavior non-invasively through PPC materials. We had the following major goals for the project associated with the following 4 questions : 1) How can PPC change the surface chemistry prior to chemical functionalization? 2) How does the concentration of dopants affect cellular behavior? 3) How does chemical functionalization affect PPC? and 4) What are the competing mechanisms of PPC-induced [Ca2+]i changes?

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Document Details

Document Type
Technical Report
Publication Date
Oct 22, 2018
Accession Number
AD1068250

Entities

People

  • Albena L. Ivanisevic
  • Ramón Collazo

Organizations

  • North Carolina State University

Tags

Communities of Interest

  • Sensors

DTIC Thesaurus Topics

  • Charge Carriers
  • Chemical Synthesis
  • Chemistry
  • Compound Semiconductors
  • Culture Techniques
  • Field Effect Transistors
  • High Electron Mobility Transistors
  • Materials
  • Materials Laboratories
  • Materials Processing
  • Materials Science
  • Measurement
  • Nanoparticles
  • Nanotechnology
  • Semiconductors
  • Surface Chemistry
  • Thin Films

Readers

  • Materials Science and Engineering.
  • Nanocomposite Materials Science
  • Nuclear and Radiation Engineering.

Technology Areas

  • Microelectronics