Current
Chemical Biology
ISSN: 1872-3136
OPEN ACCESS PLUS
Contents
Functional Characterization of Chitin and Chitosan,
2009, 3, 203-230
Inmaculada Aranaz, Marian Mengíbar,
Ruth Harris, Inés Paños, Beatriz Miralles, Niuris
Acosta, Gemma Galed and Ángeles Heras
[Abstract] [Full
Text Article]
Cause of Chirality Consensus, 2008, 2, 153-158
Salla Jaakkola, Vivek Sharma and Arto Annila
[Abstract] [Full
Text Article]
Quantum Dot Nanocrystals and Supramolecular Lanthanide
Complexes – Energy Transfer Systems for Sensitive In
Vitro Diagnostics and High Throughput Screening in Chemical
Biolog, 2007, 1, 167-186
Niko Hildebrandt and Hans-Gerd Löhmannsröben
[Abstract] [Full
Text Article]
Abstracts
[Back to top]
Functional Characterization of Chitin and Chitosan
Inmaculada Aranaz, Marian Mengíbar,
Ruth Harris, Inés Paños, Beatriz Miralles, Niuris
Acosta, Gemma Galed and Ángeles Heras
[Full
Text Article]
Chitin and its deacetylated derivative chitosan are natural
polymers composed of randomly distributed β-(1-4)-linked
D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine
(acetylated unit). Chitin is insoluble in aqueous media while
chitosan is soluble in acidic conditions due to the free protonable
amino groups present in the D-glucosamine units. Due to their
natural origin, both chitin and chitosan can not be defined
as a unique chemical structure but as a family of polymers
which present a high variability in their chemical and physical
properties. This variability is related not only to the origin
of the samples but also to their method of preparation. Chitin
and chitosan are used in fields as different as food, biomedicine
and agriculture, among others. The success of chitin and chitosan
in each of these specific applications is directly related
to deep research into their physicochemical properties. In
recent years, several reviews covering different aspects of
the applications of chitin and chitosan have been published.
However, these reviews have not taken into account the key
role of the physicochemical properties of chitin and chitosan
in their possible applications. The aim of this review is
to highlight the relationship between the physicochemical
properties of the polymers and their behaviour. A functional
characterization of chitin and chitosan regarding some biological
properties and some specific applications (drug delivery,
tissue engineering, functional food, food preservative, biocatalyst
immobilization, wastewater treatment, molecular imprinting
and metal nanocomposites) is presented. The molecular mechanism
of the biological properties such as biocompatibility, mucoadhesion,
permeation enhancing effect, anticholesterolemic, and antimicrobial
has been updated.
[Back to top]
Cause of Chirality Consensus
Salla Jaakkola, Vivek Sharma and Arto Annila
[Full
Text Article]
Biological macromolecules, proteins and nucleic acids
are composed exclusively of chirally pure monomers. The chirality
consensus appears vital for life and it has even been considered
as a prerequisite of life. However the primary cause for the
ubiquitous handedness has remained obscure. We propose that
the chirality consensus is a kinetic consequence that follows
from the principle of increasing entropy, i.e. the 2nd
law of thermodynamics. Entropy increases when an open system
evolves by decreasing gradients in free energy with more and
more efficient mechanisms of energy transduction. The rate
of entropy increase is the universal fitness criterion of
natural selection that favors diverse functional molecules
and drives the system to the chirality consensus to attain
and maintain high-entropy non-equilibrium states.
[Back to top]
Quantum Dot Nanocrystals and Supramolecular Lanthanide
Complexes – Energy Transfer Systems for Sensitive In
Vitro Diagnostics and High Throughput Screening in Chemical
Biolog
Niko Hildebrandt and Hans-Gerd Löhmannsröben
[Full
Text Article]
Resonance Energy Transfer (RET) plays an important
role, both scientifically and commercially, in diagnostics
and high throughput screening. For qualitative and quantitative
analysis, RET systems are usually assembled through molecular
recognition of biomolecules labeled with donor and acceptor
luminophores. Lanthanide complexes, as well as quantum dot
nanocrystals (QD), possess unique photophysical properties
that make them especially suitable for applied RET systems
in chemical biology.
This review deals with the RET theory, and advantages are
compared to conventional systems (using optical and other
detection techniques). Different molecular recognition processes,
as well as labeling techniques yielding biocompatibility are
described. The photophysics of Ln complexes (e.g. millisecond
luminescence decay times, line-shaped emission spectra, antenna
effect of the ligand) and of QD (e.g. high extinction coefficients,
size-tunable emission spectra, chemical stability) as well
as their RET properties are described in detail.
We give an overview of biochemical applications using lanthanide
complexes and QD, e.g. immunoassays, DNA analysis and nanometer
distance measurements (spectroscopic ruler) and some selected
results are outlined. In particular, the recent scientific
progress in biocompatible QD RET systems with the use of QD
as energy donors as well as acceptors together with Ln complexes
as donors is highlighted. The worldwide economic and scientific
interests, as well as potentials for in vitro diagnostics
(IVD) are addressed and the benefits regarding high throughput
techniques, ultrahigh sensitivity, multiplexing measurements
and miniaturization are discussed.
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