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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5881_Библиотеки_им_академика_М_И_Перельмана.pdf
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NEMS and micro-electromechanical systems (MEMS), surface properties like friction, adhesion and cohesive forces, all vital tribological components of nanomaterials can be controlled in a very precise manner that enables designing the best
possible nanobiosensing technology by modelling the biochemical interactions.
Detailed experimentation and understanding of tribological aspects of biomolecular
interfaces empower developers to undertake proper modication of the biosensing
interfaces that ultimately result in better sensitivity and longevity of the biosensing
materials [40]. Nanotribology can be used to modify the surface roughness, hydrophobicity and triboelectric properties of nanomaterials according to the need to
enhance their interaction with biomolecules and improve the signal-to-noise ratio of
nanobiosensors. Reducing friction and hence wear of nanomaterials used can seriously improve the longevity, biocompatibility and sensitivity of nanobiosensors.
Several examples show that coating nanoparticles with different novel materials can
alter their surface properties that can ultimately be exploited to generate suitable
nanobiosensors [41–43].
In this context, biotribology of nanomaterial-biomolecule/enzyme interactions
could provide substantial knowledge in improving the efcacy of the developed
sensors. In fact, mechanical wear due to frictional energy dissipation can occur in a
wide variety of possible mechanisms. To summarize, such mechanisms are maximally linked to the intrinsic structural parameters of the elements used in preparing
the nanobiocomposites viz., bonding, surface chemistry, out-of-plane deformation
and adhesion. Relevance of tribological hitches in bioMEMS or bioNEMS needs to
be broken down, as once these are overcome, nanomaterials should give exceptional
performance with acquired longevity [44]. While focusing on the tribological
aspects of biosensing, crucial factors in the effectivity of biosensors like hydrophobicity and biocompatibility should simultaneously be kept in mind, regarding the
in-vivo environment these are prepared to set in. Both the constructing element and
the lubrication or surface treatment approach should be appropriately selected and
combined to develop high-performance nanobiosensors. For example, silicon is the
most common material of interest for fabricating nanobiosensor implants. Bare or
untreated silicon possesses unsatisfactory tribological properties and requires different solid/liquid coating, lubrication or surface treatment approaches to exhibit
good tribological attributes. Also, there are high chances of rejection by the body
due to undesirable interactions between the material and the human immune system. A surface coating of proteins with high wear resistance comes handy in this
case, which simulates a biological interacting environment to x such compatibility
issues, without washing itself off while in contact with blood-ow or tissue [45]. To
consider the instance of some nanosensors based on the “lab-on-a-chip” set-up,
their modus operandi involves the owing of nanoscale volumes of the target biouid onto the chip through microchannels, aided by external pumps or internally
adjusted diaphragm micropumps which are electrostatically actuated. Here, if the
microchannel-microuid interface experiences high adhesion, the uid ow would
be restricted while the biomolecules would be found to adhere to the interacting
surface of the microchannels. In eld-effect transistor-based microarray biosensors,
the binding of the analyte with the silica substrate negates the reliability on the
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efcacy of the biosensor. Implanted nanosensors are prone to tribological setbacks,
pertaining to the frequent contact with the exterior factors like biouids and tissues,
which could potentially damage the interactive surface of the nanosensors.
Additionally, adhesion of proteins and/or cells to implanted devices not only renders the device ineffective, but also creates inammation, excessive brosis and
similar other detrimental effects [45].
In order to minimize the friction and consequent wear in such bioMEMS or
bioNEMS, several lubrication techniques have been opted for, namely peruoropolyether (PFPE) lubricant lms, self-assembled monolayers (SAMs), and hard
diamond-like carbon (DLC) coatings, many of which are hydrophobic and exhibit
low shear strength, thus contributing in their longevity. Herein, a novel term introduced in the arena of tribology is superlubricity, which signies a state of near-zero
friction and zero wear, with a 0.001 threshold value of friction coefcient [46, 47].
This phenomenon allows the effortless sliding of interacting surfaces against each
other, thus decreasing the wearability of the interacting surfaces. Superlubricity
divides itself into two branches. The solid superlubricity is highly specic to the
material under focus and the requisite conditions, and entails the attainment of this
particular state under complete dry contact. Taking the unavoidable macro-scale
structural deformation into account, solid superlubricity would generally be reached
at the nanoscale. Nevertheless, liquid superlubricity is an easily achievable form in
different scales with optimum conditions, through the usage of appropriate liquid
lubricants at the contact interface of interest [48].
Tribologists have conrmed the exponential advancement in nanoscience in
terms of achievement of superlubricity and come up with a number of nanobiomaterials which possess optimum tribological properties to achieve superlubric levels
of friction, from all the four different classes of nanomaterials. Exemplary
0- dimension nanomaterials like C60, carbon quantum dots, nanodiamonds, nanoscrolls, antimony nanoparticles and onion-like carbon can be upgraded into the
superlubric state, pertaining to their size effects. Berman etal. (2015) have exhibited the realization of superlubricity by combining graphene with nanodiamond particles or diamond-like carbons (DLCs) [49]. Then again, examples of introducing
stable liquid superlubricity with different lubricant additives like nanodiamond
glycerol colloidal solution or glycerol solutions have been found in previous literature [50]. CNTs, categorized under 1D nanomaterials, have intrinsic structural properties which willingly allow relative motion between concentric nanotubes. But
minor glitches within an incommensurate arrangement of layers might result in the
signicant increase in their shear strength. However, macroscale superlubricity in
1D nanomaterials has been accomplished by developing perfect centimetres-long
triple-walled CNTs, which provide persistent and stable superlubric character under
optimum conditions [47]. Moreover, hydrodynamic slippage at the carbon-water
interface occurring with the use of hydration lubrication has been connected to
superlubricity in CNTs in order to provide liquid alternatives of superlubricitives.
Similarly, 2D crystalline coordination polymers with square-grid structures, comprising an association of inorganic metal ions/clusters with multipoint organic
bridging linkers commonly termed as nanoscale metal-organic frameworks
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(NMOF), have exhibited prospects of achieving high solid superlubricity, due to
advantageous elimination of puckering in the inorganic-organic interface, which
concludes into lower energy dissipation, as well as the anchoring effect within the
NMOF to turn as weak as physical adsorption [44]. Other 2D nanomaterials like
phosphorenes, graphene nanoakes, graphene-based heterostructures or molybdenum disulphide, and 3D nanostructures like C60-modied graphene-oxide lms or
graphitic-like amorphous carbon/MoS2 composite coatings have also gained attention regarding implementation of superlubric applications in reality [47, 51].
A. Chakraborty et al.
3.6 Therapeutic Applications ofNanobiosensors
The use of nanotechnology in therapeutics has raised new hopes in the world of
therapeutics, as these new age or modern biosensors seem promising enough in
empowering mankind to combat diseases which are difcult to deal with or even
apparently incurable. The prime key to the improvement in the therapeutic
approaches towards any and every disease is early and efcient diagnosis [8]. For
instance, detection of tumour before the onset of metastasis enhances the probabilities of survival and returning to health. Identication of susceptible vulnerable
plaques would bring down the risks of cardiac ailments. Various microscopic,
immunosorbent or uorescent procedures have shown themselves as clinically critical, but an array of limitations also observed in them renders them less dependable
howsoever. Nanoscale sensors come with several special advantages, as particles in
this particular range of size show exceptional physical and chemical advantages.
There are a huge variety of nanomaterials that can be used in biosensor immobilization like gold, silver, and copper nanoparticles, and different carbon-based materials like graphite, graphene, and carbon nanotubes [52]. Gold nanoparticles because
of their zero toxicity and good resistance to oxidation exert potential use in nanobiosensor [53]. The upliftment of the performance of nanobiosensor is owing to
enhanced sensitivity and lower detection limit, as evidenced by the use of platinumbased nanoparticles for electrochemical amplication for the detection of low concentration of DNA [54].
3.6.1 Therapeutic Application inCancer
High mortality in cancer actually results from late detection, as treatment in
advanced stages is greatly associated with less effectiveness and treatment failure.
Besides this, nearly 60% of cancers are diagnosed after the patient’s initial tumour
has metastasized. There is a need for the use of nanobiosensors with the potential of
early non-invasive diagnostics, enhanced imaging, and advanced monitoring of
treatment progress [55]. Angiogenesis, i.e. growth of new blood vessel, that allow
easy spread of cancerous cells within body, is the most signicant aspect in cancer
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proliferation. Angiogenesis is associated with the release of angiogenic factors, like
VEGF165, which is one of the most promising biomarkers in cancer progression
diagnosis. A signal-on nanobiosensor based on bivalent aptamer-Cu nanocluster for
the detection of VEGF165 can be very much helpful for the early detection of cancer [56]. Nanoparticles deliver clinical utility both in terms of diagnostic and therapeutic use, therefore also referred to as theranostics [57]. Quantum dots have been
used for both in vitro and in vivo cancer detection. Varying wavelengths enable
recognition and tracking of differently labelled biomarkers using only a single light
source [58]. Carbon nanotubes show up to 15-fold increased detection sensitivity of
cancer antigens based on their ability to densely pack and immobilize more surface
antibodies [59].
Colorectal Cancer
A tumour suppressor gene named APC (adenomatous polyposis coli) is signicantly associated with colorectal cancer. Mutation in this gene is strongly associated
with manifestation of colorectal cancer due to formation of non-functional gene
product and inducing Wnt-signalling pathway [60]. Use of AuNP (gold nanoparticle) conjugated uorophore can increase the sensitivity of nanobiosensor where
CpG islands of APC gene are used as biomarker for detection of colorectal cancer
[61]. Chung etal., 2018 designed the sensor probe using AuNP on 2,2′:5′,2″-terthio-
phene- 3′ (p-benzoic acid) (TBA) nanocomposite lm, where the detection was done
by spectroscopy (EIS) and voltammetry [62].
Breast Cancer
Chen etal., 2009 showed that quantum dots-based uorescently labelled probe are
more sensitive than conventional immunohistochemical techniques in detecting
HER2in clinical breast cancer samples [63]. Herceptin, the antibody that targets
HER2, was attached to gold nanoparticles to allow them to use as a targeted contrast
agent while using optoacoustic tomography [64]. Shahbazi et al., 2022 use the
localized surface plasmon resonance property of gold nanoparticles to determine
HER in human serum. Here, the surface interaction was levelled up using negatively
charged citrate ions followed by its mixing with silver nanoparticles (AgNPs) to
increase sensitivity [65]. Detection of BRCA1 mutations can be an important tool in
determining risk for development of breast cancer, ovarian cancer, and prostate cancer. Salahandish etal., 2018 generate a method for label-free detection of cancer
cells with very high sensitivity. They develop gold nanoparticle-seeded functionalized graphene and nanostructured polyaniline (PANI) for high-efcacy biosensing [66].
Pancreatic Cancer
Iron oxide nanoparticles have been used with ligands like urokinase plasminogen
activator receptor (uPAR) which is a surface receptor on pancreatic tumour cells and
surrounding stromal cells [67]. Besides these, gold and silver nanoparticles have
been successfully employed for detection and diagnosis of pancreatic cancer. When
F19 human monoclonal antibodies were coupled with gold nanoparticles, it leads to
effective labelling of pancreatic carcinoma tissue, which can be visualized by
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darkeld microscopy [68]. Nedelcu et al., 2018 use dendrimer-entrapped gold
nanoparticles (Au DENPs) for the co-delivery of gemcitabine (Gem) and miR-21
inhibitor (miR-21i) in cancerous pancreatic cell [69]. Not only from diagnostic
approach was it equally helpful from therapeutic approach, but also it was found
that there was a signicant decrease in tumour volume in pancreatic tumours [70].
Lung Cancer
Lung cancer is the second among new cancer diagnosed in men and women every
year behind prostate and breast cancer. Early detection is therefore the most important and crucial for effective treatment in lung cancer as there is formation of different subtypes as the diseases progress. Carbon nanotubes, graphene oxide can be
used to design simple, label-free and cost-effective electrochemical immunosensors
for detection of lung cancer biomarkers like melanoma-associated antigens (MAGE
A2, MAGE A11) and human telomerase reverse transcriptase (hTERT) [71]. Very
recently, long non-coding RNAs (lncRNAs) have been wished-for diagnostic biomarkers and ultrasensitive electrochemical biosensor was developed using gold
nanocage coupled with multi-walled carbon nanotube (Au NCs/MWCNT-NH2)decorated screen-printed carbon electrode (SPCE). It exhibits high compatibility
along with superb conductivity and low detection limit [70].
3.6.2 Neurodegenerative Diseases
Neurodegeneration is the basis of all neurodegenerative disorders like Parkinson’s
disease (PD), Huntington’s disease, and Alzheimer’s disease (AD) and is primarily
used to describe any condition which tends to affect the normal functioning of neurons in the brain [72]. Alzheimer’s disease (AD) is characterized as a progressive
neurodegenerative disorder leading to memory decits and cognitive impairment
and is associated with the formation of plaques made up of aggregated amyloid-(A)
and Tau proteins, the central hallmarks in AD [53]. Nanotechnology utilizes engineered materials and devices which function with biological systems at the molecular level and may assist in management of neurodegenerative diseases. MRI, EMG
(electromyography), and EEG (electroencephalography) are carried out in conjugation with medical history and multiple neurological exams along with conventional
biochemical studies like immunosorbent assays (e.g. ELISA, for Alzheimer’s
amyloid-β peptides) and enzymatic assays (e.g. hexosaminidase A Tay–Sachs
assay) for treatment of NDs. Due to multifaced application of nanoparticles, they
can be utilized for brain drug delivery following proper modications to make them
biocompatible, reduced toxicity, and being able to bind and transport drugs or therapeutics. All these modications allow nanoparticles to penetrate the BBB with high
efcacy [73].
Apart from the conventional Aβ-Tau biomarker, other non-Aβ biomarkers are
available, that can be used effectively as novel biomarker for Alzheimer’s, because
of their implication in multifaced nature of neurodegenerative diseases. The levels
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of these proteins get altered as diseases progress, therefore can be used as CSF biomarker for Alzheimer. Visinin-like protein 1 (VLP-1) is the vital calcium sensor
protein, and its level is raised in Alzheimer, suggesting it as a useful biomarker that
correlates with the degree of dementia [74].
Lipid metabolites like ApoE act as promising biomarker in Alzheimer’s disease,
as the level increase with disease progress. ApoE is involved in the normal catabolism of triglyceride-rich lipoproteins and exhibits immunoreactivity in Aβ deposits
[75]. ApoE is associated with proteolytic degradation of Aβ and facilitates microglial activation via TREM2-dependent way [76].
Alzheimer’s Diseases
Treatment of Alzheimer’s is mainly targeted on Aβ-Tau. Negahdary and Heli have
designed an electrochemical peptide-based nanobiosensor using specic peptide
sequence on the surface of a microporous Au nanostructure that exhibits higher
afnity towards Aβ(1–42) [77]. Use of nanocomposite for treatment of neurodegenerative diseases is well documented. Methylene blue loaded multifunctional nanocomposite (CeNC/IONC/MSNT807) showed high binding afnity to
hyperphosphorylated tau, where CeNC alleviated mitochondrial oxidative stress
and suppressed tau hyper phosphorylation [78].
Nerve growth factor (NGF) is important for neuronal growth, but use of uncoated
magnetic nanoparticle as carrier of NGF came with problems due to their instability
in neuronal environment. This can be solved by preparing NGF functionalized
Au-coated SPIO core NPs where gold not only protects the iron oxide but also
allows controlled release of ligands [79]. DA-DNA aptamer (DAAPT)–AuNP conjugate is used to enhance the surface plasmon resonance (SPR) signal that allows
quantication of DA in the femtomolar to picomolar range [80].
Parkinson’s Disease
Loss of dopaminergic neurons in the substantia nigra (SN) pars compacta (SNpc)
with the deposition of misfolded α-synuclein protein that is found to be aggregated
into Lewy bodies in the initial stages of pathogenesis in Parkinson’s diseases [81].
A large proportion of the dopaminergic neurons get lost in the SNpc when patients
are in initially diagnosed and later neurodegeneration extends to other regions of the
central nervous system [82]. Kim etal. (2018) showed that graphene quantum dots
interact with a-synuclein and can effectively inhibit the brillization of a-synuclein.
Quantum dots can be used as effective anti-aggregation agent to prevent neuron-toneuron transmission of a-synuclein pathology induced by a-synuclein preformed
brils (PFFs) in neurons [83].
3.6.3 Infectious Diseases
Lack of effective point-of-care detection poses serious threat to global public health
from different infectious diseases, which include both viral, bacterial and parasitic
diseases. There are several conventional methods for diagnosis of infectious
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diseases like culture, RT-PCR and ELISA. But there are some operational drawbacks of these conventional methods, PCR requires well-trained personnel, operational standardization difculties, expensive while viral/bacterial culture is a very
tedious method, time-consuming. Though ELISA is rapid, it comes with low specicity and sensitivity. Therefore, the search for alternative non-invasive, rapid, highly
sensitive diagnostic method ends up in molecular diagnostic for direct, accurate
identication of specic pathogen. Apart from these, nanostructure-based biosensors are also well suited for this purpose for being highly rapid, specic and robust
method that use very low volume of sample. Optical nanobiosensor is the most
promising one due to its non-invasive nature, very low limit of detection, portability,
high sensitivity, direct naked eye detection, and easy coupling with other technology [20]. Side by side, a combination of optical biosensor with localized surface
plasmon resonance and plasmonic photothermal effect has been accepted in pathogen diagnosis along with PCR and lateral ow assay (LFA) technology, graphenebased eld-effect transistors (FET) [84].
Viral Diseases
HIV
Though PCR and ELISA are the rapid diagnostic methods already being used for
HIV detection, they have some demerits such as failure to produce precise results as
they involve quantication of RNA from the HIV [85]. Surface plasmon resonance
(SPR) is able to detect the presence of HIV viruses and different viral particles,
RNA.Improved piezoelectric biosensors with 100% specicity are more effective
HIV diagnostic methods. Photonic crystal (PC) nanostructured optical biosensors
are also used to detect HIV.Sensitive impedimetric biosensors using polyethyleneimine magnetic beads are promising in HIV diagnosis where the magnetic beads act
as label [86].
Inuenza Virus
Apart from the conventional methods, antibody-modied electrode biosensor
using sialic acid mimic pentapeptide can be used for detection of inuenza virus.
This is a form of surface biosensor using gold nanoparticle that detect anti-M antibodies. Being less expensive than ELISA, PCR may serve as a future promising
tool. Single-walled carbon nanotubes (SWCNTs) applying the CNT electric immunoassay can also be used [87].
Dengue Virus
Surface plasmon resonance (SPR)-based biosensor is the most widely used
label-free biosensors for detecting the Dengue virus. In rapid immunoglobulin M
(IgM)-based dengue diagnostic test, the anti-dengue antibody can be quickly
detected on gold biosensor chip [88]. The SERS (surface-enhanced Raman scattering) biosensor is primarily based on sensitive optical detection on the surface of
Ag-Au bimetallic device with DNA probes [89].
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Hepatitis B Infection
Hepatitis B virus (HBV) infection is the most common yet most destructive viral
infection where serological testing is the most effective way of screening to diminish transfusion-related HBV contamination. Safe immunizations and viable antiviral medications are effective to treat HBV disease. FET with CNT biosensor and
SiO2 in metal electrode was developed by Oh et al., 2009 for the detection of
Hepatitis B [90].
SARS-CoV-2 Infection
Seo etal., 2020 developed a FET-based biosensing device for the detection of
COVID-19in clinical samples without any labelling of pre-treatment [84]. Another
dual-functional plasmonic biosensor, using localized surface plasmon resonance
(LSPR) sensing transduction and the plasmonic photothermal (PPT) effect provides
an alternative method for the clinical diagnosis of COVID-19. Two-dimensional
gold nanoislands (AuNIs) are used with complementary DNA receptors for accurate detection of specic SARS-Co V2 sequence [91].
Bacterial Infection
Salmonella species, E. coli are the common bacterial pathogens responsible for
food-borne bacterial diseases in humans. Helicobacter pylori poses serious threat
due to its association with pancreatic cancer, gastric carcinoma and often shows
resistance of antibacterial substances [92]. Staphylococcus sp. is responsible for the
most common upper respiratory tract infection. Therefore rapid, easy detection of
bacterial infection is necessary for the control of these diseases, as conventional
methods require more time and skilled professionals.
E. coli Infection
Evidences of designing benign supramolecular scaffolds by associating reduced
graphene-oxide and chitosan have been found, with fruitful inferences of their antibacterial activities against E. coli and no signicant cytotoxicity towards the experimental animals used. Incorporating AuNPs further enhanced the microbial resistance
properties of the scaffold, according to Mondal etal. [93].
Staphylococcus sp. Infection
Aptamer and antibiotic-based dual recognition units with magnetic bead modied aptamer (Apt-MB) can be used for sensitive detection of Staphylococcus aureus
in the presence of other bacteria. Apt-MB and vancomycin-stabilized uorescent
gold nanocluster (AuNCs@Van) is useful in quantication of S. aureus in milk and
human serum [94]. S. typhimurium and S. aureus are mainly involved in food-borne
diseases.
Salmonella typhi
High morbidity associated with typhoid fever has increased the need for development of accurate, highly sensitive and rapid diagnostic method other than ELISA
and Widal test procedures. Singh et al., 2013 have developed biosensor with
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nanocomposites of grapheme oxide–chitosan for recognition of non-complement
sequence, one base ill-matched sequence, and complementary sequence of S. typhi
by using differential pulse voltammetry (DPV). This sensor is able to differentiate
complementary and one unmatched base sequence [95]. Rehman etal., 2015 have
analysed the impact of various nanoparticles on multiplex polymerase chain reaction (PCR) method for recognition and strain typing of Salmonella enterica serotype typhi (S. typhi) following variable number of tandem repeats (VNTR) by
employing citrate capped gold nanoparticles, rhamnolipid protected gold and silver
and magnetic iron oxide nanoparticles. The result demonstrates signicant reduction of non-specicity in PCR [96].
Mycobacterium tuberculosis
Tuberculosis (TB) caused by Mycobacterium tuberculosis is one of the most
neglected tropical diseases. Recently modern DNA hybridization-based biosensor
has been generated for effective and early diagnosis of TB.Polycarbonate membranes gold nanoparticle array tubes, i.e. bare Au electrode, probed with DNA have
been in use for the detection of DNA of Mycobacterium tuberculosis [97].
Parasitic Diseases
Parasitic diseases contribute a major portion of the global mortality as well as morbidity. There are different types of fungal as well as protozoal diseases that come
into this category. Malaria, Leishmaniasis and Amebiasis are the most important
neglected tropical diseases. Likewise, Candida sp. infection is the most common
fungal infection in human that shows many adverse severe reactions. Though
culture- based diagnostics are the gold standard for fungal diseases, they are time
time-consuming and laborious.
Malaria
The impact of malaria on global health has continually prompted the need to
develop more effective diagnostic strategies that could overcome deciencies in
accurate and early detection. There are various rapid biosensor-based methods for
malaria diagnostic like Plasmodium falciparum histidine-rich protein-2 (PfHRP-2),
parasite lactate dehydrogenase (pLDH) and aldolase. Anti-HSP 70 monoclonal antibodies coupled with gold nanoparticles and polystyrene NPs coupled to polyclonal
anti-P. falciparum IgG antibodies are very much specic for malaria parasite detec-
tion [98]. Recently Varela-Aramburu et al., 2020 have developed glucose-based
ultra-small gold nanoparticles (Glc-NCs) attached to cysteine-rich domains of
Plasmodium falciparum surface proteins, that effectively bind to extracellular and
all intraerythrocytic stages of P. falciparum as evidenced by microscopy [99].
Filariasis
An attempt by Chowdhury etal. (2018) has demonstrated AuNPs functionalized
by punching the biopolymer chitosan to exhibit exceptional antilarial properties,
without incorporation of any hazardous reducing agent [100]. Bioactive properties
like induction of oxidative stress, DNA damage and undesirable expression of
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proteins were observed through cellular and molecular level studies, which supported the claim.
Leishmaniasis
Pedro etal., 2019 described the use of nanomaterials as nanoquenchers for uorescent DNA assays. The nanostructure developed interacted with the uorophore
of a labelled DNA probe (L. infantum specic) through electron transfer processes
which resulted in quenching of the uorescence emission. Restoration of the uorescence could only be achieved in the presence of complementary DNA to the
original DNA probe [101].
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3.6.4 Metabolic Diseases
In metabolic disorder like diabetes, monitoring of patients’ blood glucose levels is
fundamental for the critical management of the disease. The invasive electrochemical method for sensing glucose is generally used among diabetes patients. So, there
is increasing demand of non-invasive biosensor for diagnosis of blood hyperglycaemia, that involves different uorescent methods. Therefore, patient-friendly, minimally invasive or non-invasive uorescent detection methods have gained attention.
Diabetes
Conventional blood glucose monitors are based on glucose oxidase biosensors,
though there are many non-invasive and electrochemical approaches like optical
methods (near-infrared reector spectroscopy), Raman spectroscopy, uorescence,
optical coherence tomography, and electrochemical optical techniques, including
infrared reector spectroscopy [102]. New approaches like macrostructural electrodes, that is electrochemical-mediated modication of nanotubes, are extensively
used that provide improvements and surface enhancements.
Fluorescent silver nanocluster conjugates developed by Dong etal., 2016 were
shown to be highly effective nanobiosensors for glucose sensing, where pH sensitivity of silver nanoclusters was used for glucose sensing [103]. Baek etal., 2020
projected a new electrospinning approach where the AuNP was coated with graphene oxide nanober and integrated inside organic-inorganic hybrid copper (Cu)nanoower. This new technique showed excellent catalytic and electrochemical
nature [104] (Table3.1).
3.7 Advantages andLimitations ofNanobiosensors
The outstanding physicochemical characteristics of nanomaterials (NMs) make
them favourable candidates (signal transducers) in the fabrication of nanobiosensors. Due to the presence of NMs, the nanosensor surfaces have numerous types of