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World Congress on Biosensors 2014
Biosensors 2014
Monday, 19 November 2012
Just Published: Biosensors & Bioelectronics
A new issue of this journal has just
been published. To see abstracts of the papers it contains (with links through
to the full papers) click here:
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue 1 Yaron
R. Silberberg, Shingo Mieda, Yosuke Amemiya, Toshiya Sato, Takanori Kihara,
Noriyuki Nakamura, Kyoko Fukazawa, Kazuhiko Ishihara, Jun Miyake, Chikashi
Nakamura A cell diagnosis technique was developed, which uses an Atomic Force
Microscope (AFM) and an ultra-thin AFM probe sharpened to a diameter of 200nm
(nanoneedle). Due to the high aspect ratio of the nanoneedle, it was
successfully inserted into a living cell without affecting its viability.
Furthermore, by functionalizing the nanoneedle with specific antibodies and
measuring the unbinding forces (‘fishing forces’) during evacuation of the
nanoneedle from the cell, it was possible to measure specific mechanical
interactions between the antibody-functionalized nanoneedle and the
intracellular contents of the cell. In this study, an
anti-actin-antibody-functionalized nanoneedle was used to evaluate the actin
cytoskeleton state in living cells. To examine the effect of cytoskeleton
condition on the measured fishing forces, the cytoskeleton-disrupting drugs
cytochalasin D (cytD) and Y-27632 were used, showing a marked decrease in the
measured fishing forces following incubation with either of the drugs.
Furthermore, the technique was used to measure the time course changes in a
single cell during incubation with cytD, showing a gradual time-dependent
decrease in fishing forces. Even minute doses of the drugs, the effects of which
were hardly evident by optical and fluorescence methods, could be clearly
detected by the measurement of nanoneedle–protein fishing forces, pointing to
the high sensitivity of this detection method. This technique may prove
beneficial for the evaluation of cytoskeleton conditions in health and disease,
and for the selection of specific cells according to their intracellular protein
contents, without the need for introduction of marker proteins into the cell.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue 1 J.P.
Golden, J. Verbarg, P.B. Howell, L.C. Shriver-Lake, F.S. Ligler A spinning
magnetic trap (MagTrap) for automated sample processing was integrated with a
microflow cytometer capable of simultaneously detecting multiple targets to
provide an automated sample-to-answer diagnosis in 40min. After target capture
on fluorescently coded magnetic microspheres, the magnetic trap automatically
concentrated the fluorescently coded microspheres, separated the captured target
from the sample matrix, and exposed the bound target sequentially to
biotinylated tracer molecules and streptavidin-labeled phycoerythrin. The
concentrated microspheres were then hydrodynamically focused in a microflow
cytometer capable of 4-color analysis (two wavelengths for microsphere
identification, one for light scatter to discriminate single microspheres and
one for phycoerythrin bound to the target). A three-fold decrease in sample
preparation time and an improved detection limit, independent of target
preconcentration, was demonstrated for detection of Escherichia coli 0157:H7
using the MagTrap as compared to manual processing. Simultaneous analysis of
positive and negative controls, along with the assay reagents specific for the
target, was used to obtain dose–response curves, demonstrating the potential for
quantification of pathogen load in buffer and serum.
Highlights
► This paper describes the first integration of the
spinning magnetic trap for automated sample preparation with an analytical
device, the NRL microflow cytometer. ► We have also included improvements in the
microflow cytometer not described elsewhere. ► The data indicate that the
combined components increase the sensitivity and reproducibility of the assays,
simultaneously reducing the assay time significantly.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue
1 Hee-Jin Jeong, Yuki Ohmuro-Matsuyama, Hiroyuki Ohashi, Fuyuki Ohsawa,
Yoshiro Tatsu, Masaki Inagaki, Hiroshi Ueda Protein phosphorylation is a key
event in intracellular signal transduction, and fluorescent biosensor for the
specific phosphorylation event in a target protein is considered highly useful
as a tool of cellular biology and drug screening. Vimentin, the most abundant
intermediate filament protein, is phosphorylated at its specific serine (Ser)
residues in a cell cycle dependent manner. Its structural and functional
characteristics are modified by the phosphorylation, which affects biological
properties of the cell. Here we present the detection of the vimentin Ser71
phosphorylation (PS71) and the vimentin Ser82 phosphorylation (PS82) using a
novel fluorescent biosensor Quenchbody, which works on the principle of
antigen-dependent removal of a quenching effect by intrinsic tryptophan residues
on a carboxytetramethylrhodamine (TAMRA) dye incorporated at the N-terminal
region of single chain antibody variable region. First, we found that rhodamine
6G (R6G)-labeled Quenchbody shows superior response than TAMRA-labeled one.
Next, we made several Quenchbodies to detect PS71 and PS82. After optimization
of reaction conditions, the fluorescence intensity of VH-VL type PS71 Quenchbody
labeled with R6G at two positions was increased to 4.0-fold in an antigen
dependent manner. Furthermore, the fluorescence intensity of doubly R6G-labeled
VL-VH type PS82 Quenchbody was increased to 6.7-fold immediately after adding
antigen peptide, also suggesting deeper quenching due to H-dimer formation
between the dyes. Due to its simplicity, the Quenchbody-based phosphorylation
biosensors will be widely applicable to in vitro diagnostics, drug screening and
imaging in a rapid, simple and high-sensitive manner.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue
1 Alfredo de la Escosura-Muñiz, Wilanee Chunglok, Werasak Surareungchai,
Arben Merkoçi A high sensitive voltammetric method for rapid determination of
thrombin spiked in whole blood by taking advantage of both aptamer-based
recognition and the use of a nanoporous membrane has been developed. The
nanoporous membrane not only acts as platform for the thrombin recognition but
also as filter of the micrometric components such as white and red blood cells,
consequently minimizing matrix effects. The protocol involves a sandwich format
in the inner walls (200nm diameter) of an anodized alumina oxide filter membrane
(AAO). The analytical signal, by DPV oxidation of [Fe(CN)6]4−, is
based on the blockage in the pores which affects the diffusion of
[Fe(CN)6]4− to the screen-printed carbon electrotransducer (SPCEs)
modified with the membrane. By labeling the anti-thrombin IgG with AuNPs
followed by silver enhancement a greater passive signal enhancement in
comparison to the membrane blockage has been observed. The contribution of both
electrostatic/steric effects in this blockage due to the subsequent formation of
the aptamer-thrombin complex and the final sandwich assay is investigated. The
efficiency of the system is also monitored by microscopic techniques. The
resulted biosensing system allows detecting thrombin spiked in whole blood at
very low levels (LOD 1.8ngmL−1) which are within the range of
clinical interest for the diagnostic of coagulation abnormalities as well as
pulmonary metastasis.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue
1 Sylvia R. Scheicher, Birgit Kainz, Stefan Köstler, Norbert Reitinger,
Nicole Steiner, Harald Ditlbacher, Alfred Leitner, Dietmar Pum, Uwe B. Sleytr,
Volker Ribitsch There is a growing demand for functional layers for the
immobilization of (bio)molecules on different kinds of substrates in the field
of biosensors, microarrays, and lab-on-a-chip development. These functional
coatings should have the ability to specifically bind (bio)molecules with a high
binding efficiency, while showing low unspecific binding during the following
assay. In this paper we present rSbpA surface layer proteins (S-layer proteins)
as a versatile immobilization layer for the development of DNA microarrays.
S-layer proteins show the ability to reassemble into two-dimensional arrays on
solid surfaces and their functional groups, such as carboxylic groups, are
repeated with the periodicity of the lattice, allowing for immobilization of
other (bio)molecules. Different fluorescently labeled amino functionalized DNA
oligomers were covalently linked to the S-layer matrices to allow the
characterization of DNA binding on S-layers. Hybridization and dissociation of
DNA-oligomers were studied on S-layer coated slides, revealing low levels of
unspecific adsorption of DNA on S-layer based immobilization matrices. In the
following the principle was transferred to a DNA microarray design showing
successful spotting and hybridization on whole microarray slides. Besides common
laser scanning for fluorescence detection, S-layer based microarrays were
evaluated with a compact, low cost platform for direct fluorescence imaging
based on surface plasmon enhanced fluorescence excitation. It could be shown
that S-layer protein layers are promising as immobilization matrices for the
development of biosensors and microarrays.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue
1 Sung-Ho Paek, Il-Hoon Cho, Dong-Hyung Kim, Jin-Woo Jeon, Guei-Sam Lim,
Se-Hwan Paek With the goal of developing a method for the continuous
monitoring of blood glucose, an implantable sensor was developed by placing an
optical fiber probe within the internal hollow space of a syringe needle. A
glucose binder, concanavalin A (Con A), was immobilized on the probe tip and a
protein (e.g., bovine serum albumin) chemically coupled with a sugar ligand
(e.g., mannose) was loaded as a solution inside of the needle, which were then
closed using a semi-permeable membrane. Upon immersion in the glucose sample,
small molecules were able to freely pass through the membrane and compete with
the ligand conjugate for Con A binding. This changed the molecular layer
thickness on the probe surfaces depending on the glucose concentration, which
shifted the wavelength of the guided light along the fiber. Such interference in
the wavelength pattern was measured using a commercial sensor system, Octet,
without employing a label. Using this analytical approach, two major steps
controlling the performance of glucose detection were overcome: permeation of
glucose (optimum with 50nm-porous polycarbonate membrane under the experimental
conditioned used) and molecular diffusion of the ligand conjugate within the
sensor compartment (19 gauge-needle, offering minimal demensions for the probe).
Under optimal conditions, the sensor was able to monitor glucose fluctuations,
even in serum medium, with a response time of less than 15min in a range
10–500mg/dL. This, however, could be further shortened down to about 5min in
principle by miniaturizing the sensor dimensions.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue 1 Takeo
Miyake, Keigo Haneda, Syuhei Yoshino, Matsuhiko Nishizawa Similar to
conventional electrolyte batteries, biofuel cells often need to be stacked in
order to boost their single cell voltage (<1V) up to a practical level. Here,
we report a laminated stack of biofuel cells that is composed of bioanode
fabrics for fructose oxidation, hydrogel sheets containing electrolyte and fuel
(fructose), and O2-diffusion biocathode fabrics. The anode and cathode fabrics
were prepared by modifying fructose dehydrogenase and bilirubin oxidase,
respectively, on carbon nanotubes-decorated carbon fiber fabrics. The total
thickness of the single set of anode/gel/cathode sheets is just 1.1mm. The
laminated triple-layer stack produces an open-circuit voltage of 2.09V, which is
a 2.8-fold increase over that of a single set cell (0.74V). The present layered
cell (5mm×5mm) produces a maximum power of 0.64mW at 1.21V, a level that is
sufficient to drive light-emitting diodes.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue 1 A.
Susloparova, D. Koppenhöfer, X.T. Vu, M. Weil, S. Ingebrandt In this study,
impedance spectroscopy measurements of silicon-based open-gate field-effect
transistor (FET) devices were utilized to study the adhesion status of cancer
cells at a single cell level. We developed a trans-impedance amplifier circuit
for the FETs with a higher bandwidth compared to a previously described system.
The new system was characterized with a fast lock-in amplifier, which enabled
measuring of impedance spectra up to 50MHz. We studied cellular activities,
including cell adhesion and anti-cancer drug induced apoptosis of human
embryonic kidney (HEK293) and human lung adenocarcinoma epithelial (H441) cells.
A well-known chemotherapeutic drug, topotecan hydrochloride, was used to
investigate the effect of this drug to tumor cells cultured on the FET devices.
The presence of the drug resulted in a 20% change in the amplitude of the
impedance spectra at 200kHz as a result of the induced apoptosis process.
Real-time impedance measurements were performed inside an incubator at a
constant frequency. The experimental results can be interpreted with an
equivalent electronic circuit to resolve the influence of the system parameters.
The developed method could be applied for the analysis of the specificity and
efficacy of novel anti-cancer drugs in cancer therapy research on a single cell
level in parallelized measurements.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue
1 Carmen C. Mayorga-Martinez, Miquel Cadevall, Maria Guix, Josep Ros, Arben
Merkoçi The rapid determination of trace phenolic compounds is of great
importance for evaluating the total toxicity of contaminated water samples.
Nowadays, electrochemical tyrosinase (Tyr) based biosensors constitute a
promising technology for the in situ monitoring of phenolic compounds because of
their advantages such as high selectivity, low production cost, promising
response speed, potential for miniaturization, simple instrumentation and easy
automatization. A mediator-free amperometric biosensor for phenolic compounds
detection based on the combination of bismuth nanoparticles (BiNPs) and Tyr for
phenol detections will be hereby reported. This is achieved through the
integration of BiNPs/Tyr onto the working electrode of a screen printed
electrode (SPE) by using glutaraldehyde as a cross-linking agent. BiNPs/Tyr
biosensor is evaluated by amperometric measurements at –200mV DC and a linear
range of up to 71μM and 100μM and a correlation coefficient of 0.995 and 0.996
for phenol and catechol, respectively. The very low DC working potential ensures
the avoidance of interferences making this biosensor an advantageous device for
real sample applications. In addition, the response mechanism including the
effect of BiNPs based on electrochemical studies and optical characterizations
will be also discussed. The obtained results may open the way to many other
BiNPs applications in the biosensing field.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue 1 Ming
Xian Lin, Kyung-A Hyun, Hui-Sung Moon, Tae Seok Sim, Jeong-Gun Lee, Jae Chan
Park, Soo Suk Lee, Hyo-Il Jung Circulating tumor cells (CTCs) are identified
in transit within the blood stream of cancer patients and have been proven to be
a main cause of metastatic disease. Current approaches for the size-based
isolation of CTCs have encountered technical challenges as some of the CTCs have
a size similar to that of leukocytes and therefore CTCs are often lost in the
process. Here, we propose a novel strategy where most of the CTCs are coated by
a large number of microbeads to amplify their size to enable complete
discrimination from leukocytes. In addition, all of the microbead labeling
processes are carried out in a continuous manner to prevent any loss of CTCs
during the isolation process. Thus, a microfluidic mixer was employed to
facilitate the efficient and selective labeling of CTCs from peripheral blood
samples. By generating secondary vortex flows called Taylor–Gortler vortices
perpendicular to the main flow direction in our microfluidic device, CTCs were
continuously and successfully coated with anti-epithelial cell adhesion
molecule-conjugated beads. After the continuous labeling, the enlarged CTCs were
perfectly trapped in a micro-filter whereas all of the leukocytes escaped.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue
1 Karina Ziółkowska, Agnieszka Stelmachowska, Radosław Kwapiszewski, Michał
Chudy, Artur Dybko, Zbigniew Brzózka In this work, we present a microfluidic
array of microwells for long-term tumor spheroid cultivation and anticancer drug
activity evaluation. The three-dimensional microfluidic system was obtained by
double casting of poly(dimethylsiloxane). Spheroids of HT-29 human carcinoma
cells were cultured in the microsystem for four weeks. After two weeks of the
culture growth slowdown and stop were observed and high cell viability was
determined within next two weeks. The characteristics of a homeostasis-like
state were achieved. A cytostatic drug (5-fluorouracil) was introduced into the
microsystem with different frequency (every day or every second day) and
different concentrations. The geometry and construction of the microsystem
enables flushing away of unaggregated (including dead) cells while viable
spheroids remain inside microwells and decreasing spheroid diameter can be
observed and measured as an indicator of decreasing cell viability. The results
have shown differences in response of spheroids to different concentrations of
5-fluorouracil. It was also observed, that higher frequency of drug dosing
resulted in more rapid spheroid diameter decrease. The presented microfluidic
system is a solution for cell-based studies in an in vivo-like microfluidic
environment. Moreover, observation of decreasing spheroid dimensions is a
low-cost, label-free and easy-to-conduct mean of a quantitative determination of
a 3D cellular model response to a applied drug. It is suitable for long-term
observation of spheroid response, in a contrary to other viability assays
requiring termination of a culture.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue
1 Qiaoli Yue, Tongfei Shen, Changna Wang, Lei Wang, Haibo Li, Shuling Xu,
Huaisheng Wang, Jifeng Liu Conjugations of oligonucleotides, chromophores,
and gold nanoparticles (GNPs) can be used for energy transfer assays to detect
DNA. Herein, a homogenous Förster resonance energy transfer (FRET) system
employing two-step modification of oligonucleotide on GNPs was reported. The
distance between the donor (fluorescein attached onto DNA) and the acceptor
(GNPs) was controlled by using the G-rich DNA. In the presence of porphyrin or
berberine, which can act as ligands of G-quadruplexes, the G-rich DNA spacer can
result into G-quadruplex structure. Therefore, the intimate contact between the
fluorophore and the GNP results in efficient energy transfer and fluorescence
quenching. After hybridization with target DNA, the G-quadruplex stretched and
resulted in an enhancement of fluorescence. So the present FRET system can be
used for target DNA sensing with detection limit as low as 40pM (S/N=3). In this
study, a relation between the fluorescence quenching efficiency and GNP sizes
was found and bigger GNPs had higher fluorescence enhancement after
hybridization with target DNA.
Publication year:
2013 Source:Biosensors and Bioelectronics, Volume 40, Issue 1 A.
Shoshi, J. Schotter, P. Schroeder, M. Milnera, P. Ertl, R. Heer, G. Reiss, H.
Brueckl Adhesion and spreading of cells strongly depend on the properties of
the underlying surface, which has significant consequences in long-term cell
behavior adaption. This relationship is important for the understanding of both
biological functions and their bioactivity in disease-related applications.
Employing our magnetic lab-on-a-chip system, we present magnetoresistive-based
real-time and label-free detection of cellular phagocytosis behavior during
their spreading process on particle-immobilized sensor surfaces. Cell spreading
experiments carried out on particle-free and particle-modified surfaces reveal a
delay in spreading rate after an elapsed time of about 2.2h for
particle-modified surfaces due to contemporaneous cell membrane loss by particle
phagocytosis. Our associated magnetoresistive measurements show a high uptake
rate at early stages of cell spreading, which decreases steadily until it
reaches saturation after an average elapsed time of about 100min. The
corresponding cellular average uptake rate during the entire cell spreading
process accounts for three particles per minute. This result represents a four
times higher phagocytosis efficiency compared to uptake experiments carried out
for confluently grown cells, in which case cell spreading is already finished
and, thus, excluded. Furthermore, other dynamic cell-surface interactions at
nano-scale level such as cell migration or the dynamics of cell attachment and
detachment are also addressable by our magnetic lab-on-a-chip approach.
Highlights
► Magnetoresistive sensing of cell spreading and
particle phagocytosis demonstrated. ► Cells uptaking particles saturate at a
smaller spreading area than reference cells. ► Difference in spreading area
accounts for required membrane area for phagocytosis. ► Sensor signal leads to
average bead-to-surface distance of 120nm after uptake. ► Uptake efficiency of
spreading cells is 4 times higher compared to confluent cells.
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