Biomedical Engineering Reference
In-Depth Information
engineering materials. Importantly, these efforts have highlighted that nanobiomaterials exhibit super-
ior cytocompatible, mechanical, electrical, optical, catalytic, and magnetic properties compared to
conventional (or micron structured) materials. These unique properties of nanobiomaterials have helped
to improve various tissue growths over what is achievable today
[28]
. Recently, nanobiomaterials,
which are materials with basic structural units, grains, particles, fibers, or other constituent components
smaller than 100 nm in at least one dimension, have evoked a great amount of attention for improving
disease prevention, diagnosis, and treatment. The intrigue in nanomaterial research for regenerative
medicine is easy to see and is widespread. For example, from a material property point of view, nano-
biomaterials can be made of metals, ceramics, polymers, organic materials, and composites thereof,
just like conventional or micron structured materials. Nanobiomaterials include nanoparticles,
nanoclusters, nanocrystals, nanofibers, nanowires, and nanofilms
[29]
.
Two types of methods exist for working with nanotechnology, each approaching the problem from
a different direction. Bottom-up methods use various processes to induce structures to self-assemble at
the scale desired. Top-down methods build a structure at a scale easily worked at to, in turn build
another structure at a smaller, unreachable scale. To date, numerous top-down and bottom-up nanofab-
rication technologies (such as electrospinning, phase separation, self-assembly processes, thin film
deposition, chemical vapor deposition, chemical etching, nanoimprinting, photolithography, and
electron beam or nanosphere lithography) are available to synthesize nanobiomaterials with ordered or
random nanotopographies. After decreasing material size into the nanoscale, dramatically increased
surface area, surface roughness, and surface-area-to-volume ratios can be created to lead to superior
physiochemical properties (i.e., mechanical, electrical, optical, catalytic, and magnetic properties).
Therefore, nanobiomaterials with such excellent properties have been extensively investigated
in a wide range of biomedical applications, in particular prosthodontics
[30]
.
2.5
Nanobiomaterials in preventive dentistry
The purpose of modern dentistry is the early prevention of tooth decay rather than invasive restor-
ative therapy. However, despite tremendous efforts in promoting oral hygiene and fluoridation, the
prevention and biomimetic treatment of early caries lesions are still challenges for dental research
and public health, particularly for individuals with a high risk for developing caries, which is the
most widespread oral disease. Recent studies indicate that nanotechnology might provide novel
strategies in preventive dentistry, specifically in the control and management of bacterial biofilms
or remineralization of submicrometer-sized tooth decay
[31
33]
. Dental caries is caused by bacte-
rial biofilms on the tooth surface, and the process of caries formation is modulated by complex
interactions between acid-producing bacteria and host factors including teeth and saliva
(
Figures 2.1A and B, and 2.2
). On exposure to oral fluids, a proteinaceous surface coating—termed
pellicle—is formed immediately on all solid substrates
[4]
. This conditioning layer, which defines
the surface charge and the nature of chemical groups exposed at the surface, changes the properties
of the substrate
[34]
. Bacteria colonize the surface by adhering to the pellicle through
adhesion
receptor interactions and form a biofilm, known as dental plaque. Maturation of the pla-
que is characterized by bacterial interactions (such as coaggregation and quorum sensing) and
increasingly diverse bacterial populations. Each human host harbors different bacterial populations,
