Functional Nanostructured Interfaces for Environmental and Biomedical Applications

Valentina Dinca, Mirela Suchea

• Publisher: Elsevier
• Year: 2019
• ISBN:
  9780128144022
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Functional Nanostructured Interfaces for Environmental and Biomedical Applications provides an overview on the characteristics of nanostructured interfaces and their processing technologies for a wide range of applications in the sensing, photocatalytic and bioengineering areas. The book focuses on the fundamentals of multifunctional nanostructured interfaces and their associated technologies, including versatile technologies, such as colloidal lithography, scanning probe techniques and laser nanostructuring, which can be used to obtain multifunctional 2D and 3D nanotextured interfaces. The book provides multidisciplinary chapters, summarizes the current status of the field, and covers important scientific and technological developments made over past decades.

As such, it is an invaluable reference to those working in the design of novel nanostructured materials.

• Covers emerging applications of nanostructured interfaces, with a focus on sensing, bio-related and environmental applications
• Provides detailed and up-to-date overviews on the characteristics of nanostructured interfaces and their processing technologies, including materials from multifunctional graphene, to extremophile materials
• Includes information about versatile technologies, such as colloidal lithography, scanning probe techniques and laser nanostructuring, all of which can all be used to obtain multifunctional 2D and 3D nanotextured interfaces

Chapter 1

Multifunctional nanostructured interfaces: Origin and challenges for biomedical and environmental applications

Mirela Petruta Suchea⁎^,†; Ioan Valentin Tudose^†,‡; Stefan Bucur^†; Valentina Dinca^§; Laurentiu Rusen^{§ ⁎} National Institute for Research and Development in Microtechnologies (IMT-Bucharest), Voluntari, Romania
^† Center of Materials Technology and Photonics, School of Engineering, Technological Educational Institute of Crete, Heraklion, Greece
^‡ Chemistry Faculty, University of Crete, Heraklion, Greece
^§ National Institute for Lasers, Plasma and Radiation Physics, Magurele, Romania

Abstract

Nanostructuring surfaces to engineer multifunctional interfaces is already routine work. This chapter will review fundamental knowledge regarding the origin of interfaces, their importance in correlation with the targeted applications, surface characterization methods, and present challenges in engineering-specific interfaces relevant for biomedical and environmental applications.

Keywords

Surfaces; Interfaces; Nanostructuring; Interfacial phenomena; Specific interfaces

Chapter outline

• 1.1 Origin of interfaces
  • 1.1.1 Definitions and terminology: Why nanostructuring?
  • 1.1.2 Fundamentals of surface engineering and modification
  • 1.1.3 Surface characterization methods
• 1.2 Phenomena at interface
  • 1.2.1 Mechanical phenomena
  • 1.2.2 Electrical phenomena
  • 1.2.3 Optical phenomena
• 1.3 Biointerfaces, present status and challenges
  • 1.3.1 Biosensing interfaces
  • 1.3.2 Cell material biointerfaces
• 1.4 Environmental applications
• 1.5 Challenges and concluding remarks
• References
• Further reading

1.1 Origin of interfaces

1.1.1 Definitions and terminology: Why nanostructuring?

Since most things cannot extend to infinity, they necessarily have boundaries. These boundaries are generally called interfaces. Basically, an interface arises as soon as we have two phases in intimate contact.

A phase is a distinct portion of space occupied by matter with properties differing from its surroundings. We have to stress that homogeneity is a necessary characteristic of a phase only at equilibrium. Although the difference between phases can be the physical state, this is not a limitation nor is the chemical composition, the most striking example being one that is exploited in order to obtain ultralow temperatures, namely, the liquefied ₂He³

₂He⁴ system.

Nanostructuring is a term that should describe the sharp change in properties that occurs at the interface; undeniably, the interface thickness is in the nanoscale, and some interfaces are structured differently than the bulk, but this is not necessarily true in all cases.

To summarize, an interface can occur in between two phases (usually, the redundant word “different” is employed to reinforce the numeral) that can be in different physical states; thus, we can have liquid-gas, solid-gas, and liquid-solid interfaces. The phases can be in the same physical state but having different chemical composition or any other discontinuity (even as subtle as the crystalline orientation); in this case, we have liquid-liquid and solid-solid interfaces only, since gases are generally miscible. There is also the case of large 1D and 2D molecules (nanotubes, graphene, etc.), atomically thin macromolecular membranes that are themselves interfaces without being phase boundaries. The particular cases in which the properties of a system are dictated by the interfaces make the object of colloid science.

1.1.2 Fundamentals of surface engineering and modification

Ideally, an interface is infinitely thin; for obvious reasons, this is not the case. The fact that real interfaces have a variable thickness (ranging from tenths to tens of nanometers) raises the problem of interface location. The thermodynamics of phase equilibrium provides with plenty models and just as many adsorption isotherms starting with the ideal Gibbs model and continuing with more refined versions. Enough to say that interfaces behave in a counterintuitive manner for instance, solid-solid interfaces behave in many aspects like liquids, while liquid-liquid interfaces behave like crystalline solids. Also, we need to mention that most phase impurities have the tendency to accumulate at the interface, fact that is beneficial for some processes, like zone melting, and a huge nuisance for others, for instance the case of doping. This fact can be attributed to adsorption equilibrium that should be seen not only as the capacity of a surface to accumulate species from the surroundings but also from its bulk.

Considering the above, we can conclude that surface engineering and surface modification should proceed smoothly being favored by adsorption processes; unfortunately, adsorption can also ruin a perfectly good surface. Up to now, we did not consider the physical interface modification that generally deals with solid-gas and solid-liquid interfaces, interfaces that we colloquially call surfaces since they tend to be the boundaries of solid objects. The physical modification usually targets a roughness-related aspect, either increasing or decreasing the surface size according to the desired applications. This physical modification can be done during the synthesis step or afterward. During the synthesis, the surface can be also functionalized; this is done, for instance, to prevent nanoparticle agglomerations or to favor growth on a specific crystallographic axis. The physical surface modification done on preexisting interfaces varies from most trivial macroscopic mechanical machining (like polishing for instance) to micro- or even nanopatterning done by lithography or laser ablation to mention a few.

1.1.3 Surface characterization methods

As applications are related to surface properties, the ability to engineer, control, and analyze surface characteristics opens up optimal opportunities for innovative and enhanced biological and environmental processes. Therefore, a critical assessment of the interfacial characteristics is necessary, various techniques related to surface composition, topography, vibration, thermodynamics, and electronic structure, being developed for this, from simple, like contact angle measurement and surface tension measurement, to highly advanced techniques XPS and SEXAFS.

As a general observation, each of the characterization technique has its limitations; therefore, understanding of the biointerface must be critically corroborated through the complementary use of analytic techniques and taking in consideration both the scale of modified surface (macro-, micro-, or nanometer) and the tissue, cell, or other biological compound of interest (North et al., 2010).

The surface tension measurement is used to estimate how strong the cohesion forces are in the interface involving a liquid phase. Most methods in this category measure directly or estimate the mass of a single drop of liquid and use that mass to calculate either directly the surface tension knowing the dimensions or indirectly repeating the experiment ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Chapter 1: Multifunctional nanostructured interfaces: Origin and challenges for biomedical and environmental applications
• Chapter 2: Chemical and physical methods for multifunctional nanostructured interface fabrication
• Chapter 3: Versatile micro- and nanotexturing techniques for antibacterial applications
• Chapter 4: Surface nanopatterning by colloidal lithography
• Chapter 5: Scanning probe techniques for nanoscale imaging and patterning
• Chapter 6: Laser processing of nanostructures: enhancing functional properties of lead-free perovskite nanostructures through chemical pressure and epitaxial strain
• Chapter 7: Extremophile-assisted nanomaterial production and nanomaterial-based biosensing
• Chapter 8: Biosensor technologies based on nanomaterials
• Chapter 9: Graphene-based materials and their biomedical and environmental applications: Recent advances
• Chapter 10: LDH-interlayered nanostructures for biomedical and environmental applications
• Chapter 11: Nanostructured ZnO-based materials for biomedical and environmental applications
• Chapter 12: Electrospun TiO2-based nanofiber composites and their bio-related and environmental applications
• Chapter 13: TiO2-based nanostructured materials with germicidal properties and other applications in biomedical fields
• Chapter 14: Applications of metallic nanostructures in biomedical field
• Chapter 15: Nanostructured tungsten oxide using pulsed laser deposition for biosensing and environmental sensing applications
• Index