TY - JOUR

T1 - Impedance Characteristics of Monolayer and Bilayer Graphene Films with Biofilm Formation and Growth

AU - Nakagawa, Ryoichi

AU - Saito, Kai

AU - Kanematsu, Hideyuki

AU - Miura, Hidekazu

AU - Ishihara, Masatou

AU - Barry, Dana M.

AU - Kogo, Takeshi

AU - Ogawa, Akiko

AU - Hirai, Nobumitsu

AU - Hagio, Takeshi

AU - Ichino, Ryoichi

AU - Ban, Masahito

AU - Yoshitake, Michiko

AU - Zimmermann, Stefan

N1 - Funding Information: Funding: This work was supported by JSPS KAKENHI (Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science, Grant Number 20K05185 and 21K12739). A part of this work was supported by the GEAR 5.0 Project of the National Institute of Technology (KOSEN) in Japan. Acknowledgments: The authors appreciate the Advanced Technology R&D Center of Mitsubishi Electric Co., Japan Food Research Laboratories (JFRL), and The Society of International Sustaining Growth for Antimicrobial Articles (SIAA) for their very useful advice and information about biofilms.

PY - 2022/5/6

Y1 - 2022/5/6

N2 - Biofilms are the result of bacterial activity. When the number of bacteria (attached to materials’ surfaces) reaches a certain threshold value, then the bacteria simultaneously excrete organic polymers (EPS: extracellular polymeric substances). These sticky polymers encase and protect the bacteria. They are called biofilms and contain about 80% water. Other components of biofilm include polymeric carbon compounds such as polysaccharides and bacteria. It is well-known that biofilms cause various medical and hygiene problems. Therefore, it is important to have a sensor that can detect biofilms to solve such problems. Graphene is a single-atom-thick sheet in which carbon atoms are connected in a hexagonal shape like a honeycomb. Carbon compounds generally bond easily to graphene. Therefore, it is highly possible that graphene could serve as a sensor to monitor biofilm formation and growth. In our previous study, monolayer graphene was prepared on a glass substrate by the chemical vapor deposition (CVD) method. Its biofilm forming ability was compared with that of graphite. As a result, the CVD graphene film had the higher sensitivity for biofilm formation. However, the monolayer graphene has a mechanical disadvantage when used as a biofilm sensor. Therefore, for this new research project, we prepared bilayer graphene with high mechanical strength by using the CVD process on copper substrates. For these specimens, we measured the capacitance component of the specimens’ impedance. In addition, we have included a discussion about the possibility of applying them as future sensors for monitoring biofilm formation and growth.

AB - Biofilms are the result of bacterial activity. When the number of bacteria (attached to materials’ surfaces) reaches a certain threshold value, then the bacteria simultaneously excrete organic polymers (EPS: extracellular polymeric substances). These sticky polymers encase and protect the bacteria. They are called biofilms and contain about 80% water. Other components of biofilm include polymeric carbon compounds such as polysaccharides and bacteria. It is well-known that biofilms cause various medical and hygiene problems. Therefore, it is important to have a sensor that can detect biofilms to solve such problems. Graphene is a single-atom-thick sheet in which carbon atoms are connected in a hexagonal shape like a honeycomb. Carbon compounds generally bond easily to graphene. Therefore, it is highly possible that graphene could serve as a sensor to monitor biofilm formation and growth. In our previous study, monolayer graphene was prepared on a glass substrate by the chemical vapor deposition (CVD) method. Its biofilm forming ability was compared with that of graphite. As a result, the CVD graphene film had the higher sensitivity for biofilm formation. However, the monolayer graphene has a mechanical disadvantage when used as a biofilm sensor. Therefore, for this new research project, we prepared bilayer graphene with high mechanical strength by using the CVD process on copper substrates. For these specimens, we measured the capacitance component of the specimens’ impedance. In addition, we have included a discussion about the possibility of applying them as future sensors for monitoring biofilm formation and growth.

KW - biofilm

KW - EPS

KW - impedance

KW - Raman spectroscopy

KW - sensors

UR - http://www.scopus.com/inward/record.url?scp=85129432732&partnerID=8YFLogxK

U2 - 10.3390/s22093548

DO - 10.3390/s22093548

M3 - Article

C2 - 35591238

AN - SCOPUS:85129432732

VL - 22

JO - Sensors

JF - Sensors

SN - 1424-8220

IS - 9

M1 - 3548

ER -