Select Page
  

please find attached the instructions + the article in PDF
screen_shot_2019_03_03_at_8.44.21_pm.png

hw_cell_based_biosensors.pdf

Don't use plagiarized sources. Get Your Custom Essay on
Cell Based Biosensors
Just from $10/Page
Order Essay

Unformatted Attachment Preview

Review
pubs.acs.org/CR
Cell-Based Biosensors and Their Application in Biomedicine
Qingjun Liu,†,‡ Chunsheng Wu,† Hua Cai,† Ning Hu,† Jun Zhou,† and Ping Wang*,†,‡

Biosensor National Special Laboratory, Key Laboratory of Biomedical Engineering of the Ministry of Education, Department of
Biomedical Engineering, Zhejiang University, Hangzhou 310027, China

State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050, China
9.4. Stem-Cell-Based Biosensors
9.5. Bioinspired Olfactory- and Taste-Cell-Based
Biosensors
9.6. Cell-Based Biosensors for Cellomics
Author Information
Corresponding Author
Notes
Biographies
Acknowledgments
References
6451
6452
6452
6453
6453
6453
6453
6454
6455
CONTENTS
1. Introduction
2. Hybridization of Cells to Chips
2.1. Cell Immobilization and Surface Modification
2.2. Microfabricated Cell Culture Chips
3. Microelectrode Array Sensors
3.1. Theories of MEAs
3.2. Design and Fabrication of MEAs
3.3. Pharmacological Applications
4. Electrical Cell−Substrate Impedance Sensors
4.1. Theories and Structure of ECIS
4.2. Monitoring of Cell Morphology and Migration
4.3. Barrier Function Assessment and Drug
Discovery
5. Field Effect Transistor Sensors
5.1. Principles of FETs
5.2. Cell Microenvironment Monitoring
5.3. Electrophysiological Detection
6. Light Addressable Potentiometric Sensors
6.1. Principles of the LAPS
6.2. Microphysiometers Based on the LAPS
6.3. Cell−Semiconductor Hybrid for Electrophysiological Detection
7. Patch Clamp Chips
7.1. Theories and Fabrication of Patch Clamp
Chips
7.2. Ion Channel Research
7.3. High-Throughput Drug Screening
8. Affinity Cell-Based Biosensors
8.1. Quartz Crystal Microbalance
8.2. Surface Plasmon Resonance
9. Future Trends of Cell-Based Biosensors
9.1. Cell-Based Biosensors Using Nanotechnology
9.2. Cell-Based Biosensors with Microfluidic
Technology
9.3. Immune-Cell-Based Biosensors
© 2014 American Chemical Society
6423
6424
6449
1. INTRODUCTION
A biosensor is an analytical device that can be used for
detecting analytes and combines a biological component with a
physicochemical detecting transducer. In recent years, biosensors have rapidly expanded and evolved in many new fields
such as molecularly sensitive receptors, biomimetic sensors, and
nanotechnologies.1−4 One of the most enduring biosensors is
the cell-based biosensor, which can detect biochemical effects
directly via living cells and convert these effects into digital
electrical signals by sensors or transducers.5−8 Hence, it serves
as the bridge between biology and electronics.
Cell-based biosensors combine living cells and sensors or
transducers for cellular physiological parameter detection,
pharmaceutical effect analysis, environmental toxicity test,
etc.9−11 In contrast to molecule-based approaches, cell-based
biosensors have a broad spectrum of detection capabilities.
Moreover, in addition to analyte sensing and detecting, cellbased biosensors can provide the advantages of rapid and
sensitive analysis for in situ monitoring with cells.12−14 Cells
naturally encapsulate molecular sensor arrays. Enzymes,
receptors, and ion channels, all with a stable status, could
respond to their corresponding analytes via a native cellular
mechanism. Compared with molecular biosensors, cell-based
biosensors are expected to respond optimally to bioactive
analytes. Therefore, cell-based biosensors provide a useful tool
to study the physiological effects of analytes. However, cellbased biosensors still suffer from some intrinsic shortcomings.
The common problems faced by the optimization of cell-based
biosensors include how to achieve satisfactory stability, how to
improve the selectivity of a special sensor design, and how to
prolong the cells’ lifetime. Fortunately, cellular mimicking and
sensing are expected to be exploited in the near future, with the
development of biotechniques such as nanotechnology, microfluidics, and high-content screening.
6450
6451
Received: August 9, 2011
Published: June 6, 2014
6424
6426
6427
6427
6429
6429
6431
6431
6433
6435
6436
6436
6437
6438
6440
6440
6442
6443
6444
6444
6446
6446
6447
6447
6448
6449
6423
dx.doi.org/10.1021/cr2003129 | Chem. Rev. 2014, 114, 6423−6461
Chemical Reviews
Review
patch clamp chips, the quartz crystal microbalance (QCM),
and surface plasmon resonance (SPR) will be introduced and
discussed in detail with conclusions and future prospects. Some
emerging technologies involving combining cell-based biosensors with up-to-date technologies in science and engineering
are discussed in detail, including the use of nanotechnology,
microelectronics, and molecular biology to fabricate the
integrated, intelligent, and bioinspired biosensors used for
cellomics studies.
Because of the obvious advantages of cell-based biosensors,
e.g., long-term recording in a noninvasive way, fast response
time, and label-free experimentation, they have been widely
utilized in many fields such as cellular physiological analysis,
pharmaceutical evaluation, environmental monitoring, and
medical diagnosis.12,15−17 In these applications, cell lines and
primary cultured cells are mainly selected as the cell sources.
Cell lines divide actively in vitro, which offers the convenience
of preparation and culture, if the desired cell type is available.
Primary cultured cells are often extracted from animals directly,
with the advantages of having numerous available cell types and
the similarity function of in vivo cells. Cell lines can serve as
renewable biosensor elements in biomedical assays, such as
toxin detection and drug screening.12 Primary cultured cells
with different cell types are usually used in bionic research,
mimicking the sensing processes of organisms, such as artificial
olfaction and gustation.18−21 To be specific, with the crucial
advantages of in situ physiological monitoring, the biosensors
can be successfully used in different biological applications
along with the special characteristics of the cells.22,23 Electric
excitability plays a significant physiological role in neurons and
cardiomyocytes, so the characteristics of excitable cells have
been commonly studied in cell-based biosensors and are used
to acquire functional information on the direct effects of
moduators/blockers to ion channels, agonists/antagonists to
ligands and receptors, and the release of neurotransmitters.10,13,24−26 On the other hand, microphysiometers are
employed to monitor the acidic metabolites of cell populations
(both adherent and nonadherent), which have good performance in receptor analysis and drug analysis.27 Besides, electrical
cell−substrate impedance sensing provides a useful method to
study adhesion, proliferation, morphology, and motility of
adherent cells with modeling of the cell as a resistor and a
capacitor.28,29 Basically, the cell type used in each sensing case
is determined by the different purposes in the biomedical
applications.
The conventional cell-based biosensors usually use cell
population recording to study the behavior of cell populations
on the basis of sensor platforms. The recorded data are often
the collective responses of many cells detected by the sensor
electrodes, which can be applied for cell−cell interaction study,
such as cell invasion and barrier function assessment.9,22,23
However, these cell population recordings cannot realize the
study of single cells and tiny bioactive units (e.g., special ion
channels or receptors). On the contrary, single-cell sensing
systems can record the cellular responses to stimuli, without
mixing information about cell−cell interaction.30 Therefore, the
single-cell sensing of cell populations is just a kind of in situ
physiological monitoring of individual cells to reflect the
behaviors of integrated cellular systems.
In this review we will systematically discuss cell-based
biosensor theories, technologies, and developments. We will
combine the descriptions of microelectronics and information
technology with those of chemical and biological fundamentals
to introduce the principles and novel applications of cell-based
biosensors. We will also provide a topical description of the
research progress of cell-based biosensors over the past two
decades. In addition, many innovative applications of cell-based
biosensors, in areas such as biomedicine, will be detailed. The
principles, developments, and typical applications of microelectrode array sensors (MEAs), electrical cell−substrate
impedance sensors (ECIS), field effect transistor sensors
(FETs), light-addressable potentiometric sensors (LAPS),
2. HYBRIDIZATION OF CELLS TO CHIPS
Intermolecular interactions between biomolecules are highly
specific. To enhance the performance of biosensor devices for
the research of biological molecular interactions, it is crucial to
achieve highly efficient coupling between the biological
molecules and transducers. In these systems, living tissues or
cells are directly immobilized onto the sensors or transducers,
which can specifically respond to chemical substances and
potentially changes in or interactions with the intra- or
extracellular microenvironment.9,31−33 Living cells or tissue is
one of the most significant components of biosensors to
produce biological signals, such as changes in ion concentration, electrical current, or voltage fluctuation. The other
components of the biosensor are mainly physical or chemical
transducers, including sensing devices and their peripheral
equipment.
Fast advancements of silicon- and glass-based microfabrication technologies have made silicon- and glass-based
sensors/devices the most common materials for the fabrication
of biosensors, such as MEA, FET, LAPS, and patch clamp
chips. In this section we will focus on the surface modification
of silicon and glass for improving biocompatibility to facilitate
the incorporation and delivery of cells and biomolecules. The
modification of other types of sensors with different kinds of
surfaces, such as metal surfaces, with poly(dimethylsiloxane)
(PDMS) and nanomaterials will be introduced in the
corresponding related sections.
Typical biosensor substrate materials are glass and silicon.
Silicon dioxide is a stable, nontoxic, and inert biomaterial. In
modern biosensors, many types of substrates, such as silicon
nitride,34,35 silicon carbide,36 photoresist SU-8,37,38 polyimide,39,40 and other organic materials, are used. Metals and
metal oxides are also widely used.41−43 Cell immobilization on
biosensor chips is one of the most important protocols and
impacts the performance of the entire cell-based biosensor
system. At present, a major research focus of surface chemistry
has been concentrated on the control of chemical properties on
the surface of sensors to satisfy the need for effective cell
immobilization. For example, many efforts have been
concentrated on the surface preparation to satisfy specific
requirements in well-defined cell−sensor interfaces, which
provide many opportunities for future development to obtain a
good interface for precise cell localization, cell network
construction, and even cell micromanipulation on biosensor
chips.
2.1. Cell Immobilization and Surface Modification
Immobilization of cells on microchips is essential for biosensor
design and downstream applications. Cells immobilized on
biosensors are quite different from common cell culture. For
biosensors, fine coupling with a silicon electric bilayer, metal
surface, PDMS surface, or nanomaterial surface is desired.
Several chemical procedures have been employed to modify the
6424
dx.doi.org/10.1021/cr2003129 | Chem. Rev. 2014, 114, 6423−6461
Chemical Reviews
Review
Figure 1. Different chemical modifications of a sensor surface for improving the cell immobilization efficiency. (a) Schematic diagram of a cell
coupled with a sensor surface by different surface modifications, including peptide, ECM, and SAM. (b) Schematic of the chemical process of cells
immobilized on a gold surface via SAM.
surface of sensors for high-efficiency cell immobilization
(Figure 1). The commonly applied methods are extracellular
immobilization methods, which mainly include two categories:
uniform chemical coating and integrated chemical coating with
surface topology. Uniform chemical coating usually uses
peptides or other extracellular matrix (ECM) components as
summarized in Table 1. Surface modification by uniform
chemical coating can greatly improve the biocompatibility of
the sensor surface, which makes cells grow and couple well
onto the sensors. However, uniform chemical coating could
also reduce the surface stability of environmental factors such as
temperature, mechanical shear, and solutions. In addition, the
uniform coating could also lead to current leakage to the
culture medium or other cells, resulting in a reduction of the
signal-to-noise ratio. To achieve cell-based biosensors with
higher performance, it is crucial to control the chemical and
physical properties of the coating materials, including the
thickness, distribution, and stability of the coating layer. On the
other hand, integrated chemical coating usually forms micropatterns on the sensor surface by microcontact printing, inkjet
printing, or a self-assembled monolayer (SAM), which could
often provide covalent linkages between cells and the sensor
surface. The micropatterns could also create precise cell
immobilization on the sensor surface, which can greatly
facilitate the measurement of cellular responses. Moreover,
covalent modifications with SAMs are experimentally simple
and quick, which improve the surface robustness to thermal,
mechanical, and solvolytic instabilities. However, not all kinds
of cells or sensors are suitable for integrated chemical coating.
For cell-based biosensors, it is important to choose the
appropriate method for cell immobilization by considering
the cellular processes and surface properties of the sensors.
Cellular processes such as adhesion, growth, migration,
secretion, and gene expression are related to the dissolved
molecules in the ECM and/or the adjacent cells. These cellular
processes can be triggered, influenced, or controlled by the
specific biomolecules distributed throughout the neighboring
surfaces in three dimensions. In vitro, cell-membrane-bound
molecules mediate the cell adhesion. ECM complex molecules
play a similar role when cells adhere onto a biosensor substrate.
One common method for facilitating the cellular immobilization onto a biosensor surface is to create a uniform adherent
layer. To accommodate different factors such as cell type,
substrate geometry, and chemical characteristics, different ECM
components and effective functional groups are immobilized.
Furthermore, ECM immobilization is combined with micropattern geometry. The target region for cell sensing is modified
with an attractive ECM, whereas other background regions are
untreated. ECM modification methods are classified in Table 1.
Because different types of microchips are applied in
biosensors, the methods of cell immobilization also vary.
Coating a biocompatible material is a convenient way to form
the functional group on the biosensor surface.44,45 ECM
components, such as polylysine,46,47 laminin,48,49 fibronectin,50−52 and collagen,53−55 can provide better adherence and
spreading of cells and tissues on the biosensors. Generally, most
of these patterning techniques are focused on guiding cells onto
substrates including uniform materials. Nowadays, innovative
technologies, integrating both the topology and biochemical
coating, have developed to assist in precisely placing the cells.
Methods such as microcontact printing,56 inkjet printing,57 and
use of an SAM,58−61 can guide cells to effectively attach to the
target region. Recent studies on cell growth factors and an
ECM revealed that some segments of the peptides, such as
RGD, IKVAV, and YIGSR,48,61,62 could govern the properties
of the whole factors or matrix. These segments could bind with
the integrin on the cell membrane to promote a series of
biochemical reactions both on and inside the membrane. It may
help the cell adhere and spread onto the sensor surface.
However, additional coating might cause the current to leak
into the culture medium, other cells, or even other electrodes
6425
dx.doi.org/10.1021/cr2003129 | Chem. Rev. 2014, 114, 6423−6461
Review
via material on the plating layer. As a result, many extraneous
noises are transferred to the electrode.
The study has found that neurons can adhere and spread on
silicon surface with the appropriate roughness.63 For enhancement of surface roughness, silicon chips are dipped into
hydrofluoric acid, which efficiently enhances the surface
roughness from the original 3 to 25 nm.64 However, to
maintain efficient signal detection, either complicated 3D
structures or more complex structural changes are allowed.
Electric properties make it impossible to etch or implant ions
into the chip surface. Some other methods are also used for cell
immobilization, such as hydroxyl ion implantation,49 aminosilanization,65−67 amino acid immobilization,68 etc., which can
significantly affect the surface properties of the silicon chips.
However, the surface modifications should be limited to
maintain their electrical properties.
2.2. Microfabricated Cell Culture Chips
ECM micropattern
inkjet printing57
self-assembled
monolayer58−61
The fast development of microelectromechanical systems
(MEMSs) has noticeably transformed biological, chemical,
and medical research. Technologies such as DNA chips,69,70
lab-on-a-chip microfluidic devices,71 and micro total analysis
system (μTAS) chips,72 are all based on biological theories and
MEMS fabrication technologies.
Lithography is the basis of modern microfabrication
technology. In general, ultraviolet (UV) light is shone through
a mask with a desired pattern. The photoresist is spattered onto
a flat substrate to form a thin film and is dried before exposure.
Biosensor substrates are generally made of glass and silicon.
Microfabrication techniques make it possible for researchers to
design the biochemistry and topology of the substrate in the
vicinity of each cell with micrometer-level controls. With the
development of microfabrication technology, BioMEMSs have
been greatly encouraged to assist with cell immobilization on
biosensors.
Some BioMEMS strategies are applied in immobilizing cells
on sensors. First, biosensor design is combined with topology
methods, which guides cell orientation by artificial microstructures.38 The BioMEMS helps to record the distribution
and changes in the current of the neuronal networks, typically
via the FET array.73 This provides a practical method for longterm monitoring of cells via a microelectronic circuit. Various
microstructures are fabricated on silicon for trapping cells and
are tested separately.73−75 Some researchers used microholes
with a diameter of 150 μm to facilitate cell adherence.76 Figure
2 shows neurons that were immobilized in a microfence.77
Others managed to design micropyramids,34,78 microchannels,79,80 and microwells74,81 on the chips to guide cell
adhesion.74,81 Neuron was positioned that the network was
oriented as the ideal model and formed synapses artificially.
However, it is too difficult to control the processes precisely
enough to fabricate complicated microstructures on the chips.
Soft lithography is a modern and economic technology to
generate a transparent rubber pattern utilizing PDMS, due to
the reusability of the master mold. Soft lithography is a
promising and attractive technology for biologists for cell
immobilization.
For scaffolds made of PDMS, a stencil and agar could be
used to hold the cells and support them for more complex 3D
structures. PDMS is satisfactorily biocompatible, stable, nontoxic, and suitable for cells as a …
Purchase answer to see full
attachment

Order your essay today and save 10% with the discount code ESSAYHSELP