Nanotechnology and the Diagnosis of Dermatological Infectious Disease
July 2012 | Volume 11 | Issue 7 | Original Article | 846 | Copyright © July 2012
Karin Blecher Paz MDa and Adam Friedman MD FAADa,b
aDivision of Dermatology and bDepartment of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY
Abstract
Despite advances in diagnostics and therapeutics, infectious diseases continue to be a major cause of morbidity and mortality, surpassing
cardiovascular diseases and cancer. Accurate identification of causative pathogens is critical to prevent the spread of infectious diseases
and to deliver appropriate and timely therapy. Various limitations ranging from cost to lengthy yield times of current diagnostic modalities
highlight the need for new approaches. Nanotechnology represents an innovative direction offering many advantages for pathogen
detection and identification. Through surface modifications, nanoparticles can be tailored to bind microbial surface markers, nucleic acids,
and toxins. Combining these nanoparticles with both standard and developing detection technologies has led to the development of
faster, more sensitive, and more economical diagnostic assays. This review will focus on the diagnostic advances that utilize fluorescent,
metallic, and magnetic nanomaterials, highlighting their potential applications in the diagnosis of infectious dermatological conditions.
J Drugs Dermatol. 2012;11(7):846-851.
INTRODUCTION
Despite advances in diagnostics and therapeutics, infectious
diseases continue to be a major cause of
morbidity and mortality, surpassing cardiovascular
diseases and cancer.1 Accurate identification of causative pathogens
is critical to prevent the spread of infectious diseases and
to deliver appropriate and timely therapy. However, conventional
diagnostic techniques such as microscopy, immunoassays
(including fluorescent immunoassays, agglutination tests,
and enzyme-linked immunosorbent assays [ELISA]), and polymerase
chain reaction (PCR) have limitations.2-4 For example,
microscopy-based methods require samples with high pathogen
concentrations as well as long incubation periods to yield
results. Moreover, some microorganisms, especially viruses,
are not easily grown in culture, making their identification even
more challenging. Immunoassays and PCR are highly sensitive,
however they require extensive sample preparation, utilize expensive
reagents, and have long readout times.3,4 These limitations
also restrict the use of these conventional techniques to
clinical laboratories, and render them impractical for use in the
field or in developing countries where resources are scarce and
infectious diseases are a major source of morbidity.4
Nanotechnology offers many advantages for pathogen detection
and identification. Through surface modifications, nanoparticles
can be tailored to bind microbial surface markers, nucleic acids,
and toxins. Combining these nanoparticles with novel detection
technologies has led to the development of faster, more sensitive,
and more economical diagnostic assays.3,4 This review will
focus on the diagnostic advances that utilize fluorescent, metallic,
and magnetic nanomaterials (Table 1), highlighting their
potential applications in the diagnosis of infectious diseases,
specifically infectious dermatological conditions.
Fluorescent Nanomaterials
Fluorescent labeling can be used to identify and track specific
molecules of interest,5 however, conventional techniques that
utilize organic dyes and fluorescent proteins are limited by broad
emission spectra, fast photobleaching, and low signal-to-noise
ratios. In contrast, fluorescent nanoparticles (NPs) are filled with
thousands of organic fluorophores and thus overcome the inadequacies
of conventional fluorescent markers.6 Thus, fluorescent
NPs represent a new class of photostable, highly-sensitive tags for
labeling of biological samples.4
Quantum Dots
Quantum dots (QDs) are colloidal semiconductor nanocrystals
composed of materials in the periodic groups II-VI (eg, CdSe) or
III-V (eg, InP).4,5,7 Less than 10 nm in diameter, QDs offer significant
advantages over conventional markers including narrow emission
spectra, high resistance to degradation, and broad excitation
spectra that can be adjusted based on size and composition to
wavelengths from the ultraviolet to near infrared regions.3,8
Many studies have investigated the potential of QDs for imaging
and detection of infectious pathogens including viruses, bacteria,
and fungi. The identification of Respiratory Syncytial Virus (RSV)
both in vitro and in vivo was accomplished through the coupling