Bulk and Surface Electronic Properties of Inorganic Materials: Tools to Guide Cellular Behavior

Abstract

Classical concepts associated with the electronic properties of inorganic materials in the context of conditions used in biointerface studies are summarized. Electronic properties provide unique ways for stimulating a variety of biological systems; however, here the major focus is on mammallian cells. An additional focus is placed on bulk and electronic properties prior to chemical functionalization of inorganic materials. Representative studies, challenges, and opportunities toward utilization of charge, conductivity, photoconductivity, polarity, and piezoelectricity‐dependent mamallian cell interfaces are highlighted.

Behavior of E. coli with Variable Surface Morphology Changes on Charged Semiconductor Interfaces

“…We have reported on a number of detailed GaN characterization studies . In particular, we have examined changes in the surface chemistry and roughness via spectroscopy and microscopy analysis .…”

“…We have reported on a number of detailed GaN characterization studies. 17 In particular, we have examined changes in the surface chemistry and roughness via spectroscopy and microscopy analysis. 37 In this study, we quantified the surface potential changes of the batch of Ga-polar GaN utilized for the biofilm behavior studies.…”

“…Understanding the interactions of microorganisms with semiconductors will lead to new paradigms in the field of bioelectronics. , In particular, there are a number of unique semiconductor properties that can be utilized to influence the behavior of cells on these interfaces . We have recently reported on the favorable biocompatibility properties of III-nitrides and the ability to tune adhesion via topography and surface chemistry .…”

“…15,16 In particular, there are a number of unique semiconductor properties that can be utilized to influence the behavior of cells on these interfaces. 17 We have recently reported on the favorable biocompatibility properties of IIInitrides and the ability to tune adhesion via topography and surface chemistry. 18 However, these semiconductors also have persistent photoconductivity associated with the accumulation of surface charge and a change in surface potential that persist with long lifetime even after the source used for photoactivation, such as UV light, is removed.…”

Oxidative Stress Transcriptional Responses of Escherichia coli at GaN Interfaces

“…The surface properties of semiconductors can be modified using approaches such as surface chemistry and light stimuli to engineer surfaces that modulate microbial interactions. The role of surface properties for biointerface applications has been widely studied for biomedical applications such as cell-instructive surfaces, neural interfaces, and in vitro sensing applications. − Although relatively less explored, understanding the interactions of microbes at semiconductor surfaces is important for bioelectronics applications. TiO 2 and ZnO have been studied with a particular focus on the influence of nanostructures and photocatalytic properties on modulating microbial interactions for antimicrobial and biosensor applications. , Although Si is common for bioelectronics applications, the biocompatibility and wide band gap properties of III-nitride materials are advantageous in comparison for applications including sensing and communication devices. ,− Additionally, the treatment of GaN with chemicals such as H 2 SO 4 , H 3 PO 4 , and KOH and functionalization with organic adsorbates can modify the surface properties of the substrates. − We have reported on the topography and surface chemistry modifications of GaN and Al x Ga 1– x N using wet chemical etching and functionalization with organic adsorbates. ,,− Additionally, GaN exhibits persistent photoconductivity (PPC) which is the slow decay of surface charge that accumulated under UV light exposure after the light stimulus is removed.…”