PROSPECTIVES
Towards biomimetic electronics that emulate cells
Claudia Lubrano, Istituto Italiano di Tecnologia, and Università degli Studi di Napoli Federico II, Italy; Giovanni Maria Matrone, Istituto Italiano di Tecnologia, Italy; Csaba Forro, Istituto Italiano di Tecnologia, Italy, and Stanford University, USA; Zeinab Jahed, Stanford University, USA; Andreas Offenhaeusser, Forschungszentrum Jülich GmbH, Germany; Alberto Salleo, Bianxiao Cui, Stanford University, USA; Francesca Santoro, Istituto Italiano di Tecnologia, Italy
Bioelectronics aims to design electronic devices that can be fully integrated within tissues to monitor or stimulate specific cell functions. The main challenge is the engineering of the cell–chip interface and diverse materials, and devices have been developed to recapitulate biological architectures and functionalities. The authors give an overview on how the bioelectronics community has exploited biomimetic approaches to emulate cell morphologies, interactions, and functions to design optimal electrical platforms to be coupled to living cells. doi.org/10.1557/mrc.2020.56
Additive manufacturing for COVID-19: Devices, materials, prospects, and challenges
Rigoberto C. Advincula, The University of Tennessee, Knoxville, and Oak Ridge National Laboratory, USA; John Ryan C. Dizon, Bataan Peninsula State University, Philippines; Qiyi Chen, Oak Ridge National Laboratory, USA; Ivy Niu, Jason Chung, Lucas Kilpatrick, Reagan Newman, The University of Tennessee, Knoxville, USA
The current COVID-19 pandemic has caused the shortage of personal protective equipment (PPE) where improvised manufacturing, in particular three-dimensional (3D) printing has addressed many needs. The authors discuss the current global crisis, then follow the wide interest in addressing the shortage of medical devices and PPE used for treatment and protection against pathogens. An overview of the 3D printing process with polymer materials is given followed by the different 3D printing projects of PPE and medical devices that emerged for the pandemic (including validation/testing). The potential for rapid prototyping with different polymer materials and eventual high throughput production is emphasized. doi.org/10.1557/mrc.2020.57
Architected mechanical designs in tissue engineering
Zacharias Vangelatos, University of California, Berkeley, USA; Chenyan Wang, Zhen Ma, Syracuse University, USA; Costas P. Grigoropoulos, University of California, Berkeley, USA
The deeper comprehension of biological phenomena has led to the pursuit of designing and architecting complex biological systems. This has been incorporated through the advances in bioprinting of artificial organs and implants even at microscale. In addition, tissue modeling has been employed to understand and prevent malfunctional and detrimental mechanisms that lead to fatal diseases. Furthermore, the endeavor to convey the mechanical properties of both scaffolds and cells has enabled the unveiling of disease modeling and regenerative medicine. The authors aim to provide a brief review on the design, modeling, and characterization of conventional and architected structures employed in bioengineering. doi.org/10.1557/mrc.2020.60
Toward bioimplantable and biocompatible flexible energy harvesters using piezoelectric ceramic materials
Chang Kyu Jeong, Jeonbuk National University, Republic of Korea
The author presents a comprehensive overview of currently available research on bioimplantable energy harvesters, with a specific focus on their fabrication and issue of biocompatibility. Both the achievements and limitations of the field are pointed out from the standpoint of materials science and engineering as directions for future research. Particular attention is paid to the controversy over the use of lead-based or lead-free piezoelectric ceramics in biomedical applications, which is closely related to different temporalities of research on biological conditions. This report is intended to serve as a reference guide for developing the next generation of piezoelectric biomedical devices. doi.org/10.1557/mrc.2020.48
RESEARCH LETTERS
Water flow enhancement in amorphous silica nanochannels coated with monolayer graphene
Enrique Wagemann, Diego Becerra, Universidad de Concepción, Chile; Jens H. Walther, Technical University of Denmark, Denmark, and ETH Zürich, Switzerland; Harvey A. Zambrano, Universidad Técnica Federico Santa María, Chile
Inspired by the recently reported translucency of monolayer graphene (GE) to wetting, atomistic simulations are employed to evaluate water flow enhancement induced by GE deposited on the inner surfaces of hydrophilic nanochannels. The flow in the coated channels exhibits a slip length of approximately 3.0 nm. Moreover, by contrasting the flow rates in channels with coated walls against flow rates in the corresponding uncoated channels, an “effective” flow enhancement from 3.2 to 3.7 is computed. The probability-density function of the water dipole orientation indicates that the flow enhancement is related to a thinner structured water layer at the solid–liquid interface. The authors provide quantitative evidence that GE employed as a coating reduces substantially hydraulic losses in hydrophilic nanoconfinement. doi.org/10.1557/mrc.2020.53
Investigation of thermal transport properties in pillared-graphene structure using nonequilibrium molecular dynamics simulations
Khaled Almahmoud, Thiruvillamalai Mahadevan, Nastaran Barhemmati-Rajab, Jincheng Du, Huseyin Bostanci, Weihuan Zhao, University of North Texas, USA
The authors focus on calculating the thermal conductivity of pillared-graphene structures (PGS). PGS consists of graphene and carbon nanotubes (CNTs). These two materials have great potential to manage heat generated by nano- and microelectronic devices because of their superior thermal conductivities. However, the high anisotropy limits their performance when it comes to three-dimensional heat transfer. Nonequilibrium molecular dynamics simulations were conducted to study thermal transport of PGS. The simulation results suggest that the thermal conductivity along the graphene plane can reach up to 284 W/m K depending on PGS parameters, while along the CNT direction, the thermal conductivity can reach 20 W/m K. doi.org/10.1557/mrc.2020.58
Nature-inspired spherical silicon solar cell for three-dimensional light harvesting, improved dust, and thermal management
Nazek El-Atab, Nadeem Qaiser, Wedyan Babatain, King Abdullah University of Science and Technology, Saudia Arabia; Rabab Bahabry, University of Jeddah, Saudi Arabia; Rana Shamsuddin, King Abdulaziz University, Saudi Arabia; Muhammad Mustafa Hussain, University of California, Berkeley, USA
Unconventional techniques to benefit from the low-cost and high-efficiency monocrystalline silicon solar cells can lead to new device capabilities and engineering prospects. Here, a nature-inspired spherical solar cell is demonstrated, which is capable of capturing light three-dimensionally. The proposed cell architecture is based on monocrystalline silicon and is fabricated using a corrugation technique. The spherical cell shows an increase in power output by up to 101% with respect to a traditional flat cell with the same projection area using different reflective materials. Finally, the spherical cell shows advantages in terms of enhanced heat dissipation and reduced dust accumulation over conventional cells. doi.org/10.1557/mrc.2020.44
Synthesis of self-assembled siloxane–polyindole–gold nanoparticle polymeric nanofluid for biomedical membranes
Prem C. Pandey, Naman Katyal, Indian Institute of Technology, India; Govind Pandey, King George's Medical University, India; Roger J. Narayan, University of North Carolina, and North Carolina State University, USA
The Lewis base character of 3-aminopropyltrimethoxysilane (3-APTMS), an imine derivative of siloxane and an indole monomer, were shown to enable the reduction of gold cations in acetone. The Lewis acid–base adduct of indole monomers and gold formed a polyindole–gold nanoparticle sol. Similarly, the Lewis acid–base adduct of 3-APTMS and gold enabled the formation of gold nanoparticles in the presence of acetone. The polyindole–gold nanoparticle sol and siloxane–gold nanoparticles underwent self-assembly into a polymeric nanofluid that was suitable for casting membranes. The use of these membranes as a potentiometric ion sensor for both cations and anions was considered; a common nonspecific ion exchange molecule, sodium tetraphenylborate, and the polymeric nanofluid were used to prepare an anion sensor and a cation sensor. doi.org/10.1557/mrc.2020.50
