Tuberculosis (TB) is an infectious and contagious disease caused by various strains of
Mycobacterium worldwide
viz. Mycobacterium bovis (bovine TB),
Mycobacterium avium (avian TB) and
Mycobacterium tuberculosis (human TB), and the foremost leading cause of death of animal and human population
(Bapat et al., 2017; Sidhu et al., 2020). At the very beginning in 1882, Robert Koch discovered
Mycobacterium as causative agent of TB. The contagious disease is mainly transmitted through minute droplets of aerosol containing mycobacteria. Tuberculous infected and carrier animals within the herd contribute to environmental contamination and spread of infection to animals and human
(Bharti et al., 2018).
The data gathered by World Organization of Animal Health stated that among 179 countries of world, more than half were reported with the presence of zoonotic TB in livestock and/or wildlife, demonstrating its wide geographical spread
(Dean et al., 2018). In 2012 the International Livestock Research Institute screened livestock globally for tuberculosis and they found that more than 7 per cent of tested livestock were positive. An overall prevalence of tuberculosis was found in bovine 8 per cent, camels 11 per cent, shoats 2 per cent, pigs 15 per cent and wildlife 5 per cent
(Grace et al., 2012). This has also been noted by scientists that the 40-60 per cent cattle of herds are found infected in developing countries (
Senthilingam 2015).
In April 1993 TB was declared a global emergency by the WHO. Although an estimate, 2 billion persons or approximately one third of the world’s population are infected with contagious tuberculus bacillus among which 95 per cent of cases occur in people of developing countries. The deadly disease is responsible for the death of 1.5 to 2 million people per year (
WHO 2011). According to the World Health Organisation (WHO), estimate 147,000 new cases and 12,500 deaths are because of zoonotic TB in human (
Olea-Popelka and Fujiwara 2018). However, the prevalence of mycobacterial infection causing TB is far higher; it is estimated that only 10-12 per cent of infections result in overt disease
(Doherty et al., 2009; Lu et al., 2016). Due to chronic persistence of
Mycobacterium infection farmers, dairy workers, zoo keepers and veterinarian are at greater risk.
Most recently in developing countries especially in India, rare and very dangerous forms of TB (XDR-TB) have emerged. To combat this situation, collaborative road map has been developed by the WHO, the Office International des Epizooties (OIE), the Food and Agricultural Organization (FAO) of the United Nations (UN) and International Union against Tuberculosis and Lung diseases addressing the major health and economic impact to eradicate tuberculosis by the year 2030 (
FAO 2017).
Researchers have proved that most of the active TB infections are curable with early diagnosis followed by appropriate treatment. Beside that in animals, immune-deficient and immune-compromised individual TB treatment is much difficult as most of the times it gets undiagnosed since conventional diagnostic tools are unable to diagnose. However, currently available modern diagnostic techniques are useful but they neither rapid nor cost effective for early accurate and affordable diagnosis, represents a cornerstone to eradicate TB worldwide by 2030.
To overcome this awful situation an innovative strategy
i.e. nanotechnology for TB diagnosis has been recently introduced. Current researches have proved that the unique properties of nanoparticles (NPs), allowed their utilization in TB detection via targeting disease biomarker
(El-Samadony et al., 2017). The present article discuss about recent advances using nanotechnology in TB diagnosis.
I. Status of tuberculosis in livestock
An overall prevalence of bovine tuberculosis in India was found to be 14.31 per cent to 34.42 per cent
(Saminathan et al., 2016). Srinivasan et al., (2018) reported 7.3 per cent prevalence of bovine tuberculosis in India after systematic review and meta-analysis of 44 publications from 1942 to 2016
(Srinivasan et al., 2018). It is estimated that the seroprevalence of tuberculosis infection among captive elephants in southern India is nearly 15 per cent
(Zachariah et al., 2017). In India over 70 per cent of the milk is sold unpasteurized, this raises concerns regarding the potential for zoonotic transmission of TB. India has the world’s largest burden of human TB
(Thoen et al., 2006).
Tuberculosis was found positive in 27.77 per cent cattle and 1.12 per cent goat of Madhya Pradesh
(Bassessar et al., 2014 and
Swamy et al., 2017). Srinivasan et al., (2018) reported 6.3 per cent prevalence of bovine tuberculosis in Madhya Pradesh.
ll. Use of nanotechnology in diagnosis of tuberculosis
With the critical review of researches, this section discusses how nanotechnology is helpful for early diagnosis of tuberculosis in short time with increased sensitivity and specificity through nano sized biomolecular interaction
viz. enhanced visualization of fluorescent signals, visual colorimetric signals of amplified DNA product, nanofluidic technology, nuclear magnetic resonance technology (NMR) and prototype miniaturized device
etc.
1. Fluorescent nanodiagnosis
A. Based on lateral flow immunochromatography assay
In a lateral flow immunochromatography based assay, MTB 38 kDa monoclonal antibody in blood is rapidly detect by gold nanodoped dual channel lateral flow immunochromato-graphy strips. In this nanodoped immunochromatography strips protein A labelled with 40 nm gold nanoparticles is used as the detection conjugate. This detection conjugate is further labeled by anti-protein A at control lines and fusion antigen MTB 6-14-38 kDa at test line as the capture proteins. In TB positive sample the fusion antigen labelled with 40 nm gold nanoparticles in strip rapidly capture monoclonal antibody and produce positive result
(Maduli et al., 2014). The effect of the analyte concentration on the MTB lateral flow assay is obtained from an ESE Quanti reader. This nano-doped lateral flow assay has detection limit of 5 ng/ml. The fluorescence intensity gets increased with an increase in the concentration of MTB 38 kDa monoclonal antibody (
Banrjee and Jaiswal 2018).
In a nanodiagnostic technique, lateral flow immunochromato-graphy device combined with quantum dots (QDs) technology is used to detect specific myco-bacterial flavoprotein reductase (
fprA)
(Cimaglia et al., 2012). In this lateral flow immunochromatographic assay, quantum dot labelled antibodies that act as fluorescent tracers, immobilize monoclonal antibody onto the detection zone of a porous nitrocellulose membrane. The improved lateral flow assay gives a good fluorescence signal, intensity which is directly proportional to the concentration of
fprA protein. Quantum dot doped lateral flow device has detection limit of
fprA protein at concentrations 12.5 pg/μL within 10 min, which is quite more sensitive than other platform tests
(Di-Nardo et al., 2016).
B. Based on indirect immunofluorescence microscopy
The Indirect immunoflurescence microscopy based fluorescent nanodiagnostic technique gives rapid diagnosis by using fluorescent silica nanoparticle. The technology can detect
Mycobacterium in bacterial mixture and clinical samples (
El-Samadony et al., 2017). In this technique an anti-
Mycobacterium antibody is used as primary antibody to recognize
Mycobacterium, by an antibody binding protein (Protein A) labelled with Tris (2,2- bipyridyl) dichlororuthenium (II) hexahydrate (RuBpy) doped silica nanoparticles is used to generate fluorescent signal on microscopic examination. These fluorescent silica nanoparticles amplify signal intensity and enhance photo stability. It has also been observed that the silica nanoparticles have extremely high sensitivity and low false positivity
(Ekrami et al., 2011 and
Sudha 2016).
C. Based on flow cytometric analysis
In a two-colour flow cytometric analysis technique, bioconjugate fluorescent silica nanoparticles and nucleic acid dye SYBR Green I (FSiNP@SG-FCM), use to detect
Mycobacterium in clinical samples as low as 3.5×10
3 to 3.0×10
4 cells ml
-1. The sensitivity of this technique is higher than the FITC-based conventional flow cytometry. In this method
Mycobacterium of clinical samples are get detected by antibody-conjugated RuBpy-doped fluorescent silica nanoparticles (FSiNPs), which is then it stained with a nucleic acid dye SYBR Green I, this nucleic acid dye exclude background detrital particles (
Veigas et al., 2015).
The technique, gives decreased false positives aggregates of nanoparticle-bioconjugates and also decreased nonspecific binding of nanoparticle-bioconjugates to background debris. A total time of 2 h is required for the assay including sample pretreatment
(Qin et al., 2008).
2. Nucleic acid hybridization nanodiagnosis
A. Based on unmodified nanoprobes
Gold (Au) nanoparticle based nanoprobes are successfully used in specific identification of TB by various scientists all over the world. These nanoprobes (Au, Ag, Zr
etc.) have capability of differentiating members of the mycobacteria on the basis of gyrB locus.
In a nanodiagnostic technique unmodified spherical AuNPs can detect TB 16s rDNA specific oligo-targeters from clinical samples. This assay prototype can directly detect unamplified
Mycobacterium DNA using a single oligo-targeter (
Gazi et al., 2018). The prototype detection limit of this assay is 1 ng for PCR product and 40ng for genomic DNA. Scientists have proved that testing clinical specimens with the nano-gold assay prototype generated results are more sensitive to those obtained with using bacterial culture method and semi-nested PCR
(Hussain et al., 2013).
B. Based on modified nanoprobes
A cost-effective nanodiagnostic biosensor technique, that specific to TB diagnosis immobilize DNA probe and deposit it on nano-structured metal oxides Zirconia (ZrO2) film (crystallite size 35 nm). The nano-crystalline transparent ZrO2 is an attractive inorganic metal oxide with thermal stability, chemical inertness, non-toxicity and affinity for groups containing oxygen which facilitates covalent immobilization without using any cross-linker that may limit sensitivity of the fabricated sensor. The DNA-ZrO2 /Au is found to have stability as four months when stored at 4°C and detection limit of 0.065 ng/µl to target DNA concentration and 1 ng/µl of genomic DNA. This nanodianostic technique can be used for rapid and early detection of
M. tuberculosis (
Das et al., 2010).
In a novel nanodiagnostic strategy, the LAMP-AuNP probe method, showed no cross reaction with other mycobacteria and offered a short total assay time of <1 h. Scientists have proved that this assay is highly sensitivity, takes relatively shorter analysis time, cost effective and has lack of requirement for a thermocycler and separate detection reagents. Therefore, the LAMP-AuNP MTB probe assay constitutes a safe and simple alternative to traditional PCR for the rapid and sensitive detection of MTB DNA
(Kaewphinit et al., 2017).
3. Optical biosensor nanodiagnosis
A. Based on surface-enhanced raman scattering (SERS)
Scientists enable spectroscopic fingerprints of mycobacterial strains in few seconds using Raman spectroscopy. Recently more advanced surface-enhanced Raman scattering (SERS) technique that made of an array of silver nanoparticles imbedded in anodic aluminium oxide (AAO) in nanochannels
(Wang et al., 2006). The SERS-based diagnostic technique is applied to assess the fine structures of the bacterial cell wall and can detect single bacterium directly on clinical specimen instead of pure cultured bacteria
(Liu et al., 2009 and
Zhou et al., 2015).
B. Based on surface plasmon resonance (SPR)
In a surface plasmon resonance based nanodiagnostic technique
Mycobacterium specific antigens (
e.g., CFP-10 antigen) present in tissue fluid are visualized by binding to nanoparticles (
e.g. gold) on its optical sensor surface
(Bak et al., 2018). In this method, a monoclonal anti-CFP10 antibody is first immobilized on a commercially available immunosensor chip and then chip integrated with an SPR-based optical immunosensor system (BiaCore 3000, Sweden). This system utilizes the CFP10 antigen as a sensitive TB marker (
Hong et al., 2011). A linear relationship between SPR angle shift and values of CFP-10 concentrations are in the range from 0.1 to 1 µg/ml on SPR detection system. This newly developed and self-assembled SPR optical immunosensor system offers the advantages of simplicity of immobilization, low sample requirement, label-free, no pretreatment, high sensitivity, high specificity and high reusability. This is assumed that in future it will be used for home care and point-of-care in early diagnosis of TB.
4. Electrical conductive nanodiagnosis
In recent years tuberculosis furthermore get detected by electrical conductivity based different readout signals such as piezoresistive response, conductance change and voltammetry.
A. Piezoresistive based nanodiagnosis
The piezoresistive effect is a change in the electrical resistivity of semiconductor or metal when mechanical strain is applied. In Piezoresistive based nanodiagnosis a nanocantilever device is used to detect
Mycobacterium. The specific TB antibodies against antigen 85 complex are immobilized on upper surface of cantilever. A cantilever device is a spring board where after antigen capture spring board bend and facilitate presence of TB by measuring the capacitance and resonant frequency in attached micromechanical biosensors. The micromechanical biosensors work as standard silicon technology in these nanocantilevers. The electrostatically actuated and intrinsic flexibility allow nanocantilever for biomolecular recognition in low cost (
Sangeetha and Juliet 2013).
In a piezoresistive based nanodiagnostic technique Quartz crystal microbalance (QCM) biosensor combined with gold nanoparticle is used to detect
Mycobacterium. In this diagnostic technique QCM sensing surface is immobilized with anti-MTB antibodies. This sensing surface capture MTB from clinical sample, after capturing mycobacteria the frequency shift made due to change in mass loading on sensor is monitored in real time with detection limit of 10
5 CFU/ml (
He and Zhang 2002). Although this diagnostic technology is rapid, simple and label-free, its accuracy is affected by a number of factors such as density, viscosity, dielectric constant and electrical conductivity of the sample
(Ren et al., 2008).
2. Nucleic acid hybridization nanodiagnosis
A. Based on unmodified nanoprobes
Gold (Au) nanoparticle based nanoprobes are successfully used in specific identification of TB by various scientists all over the world. These nanoprobes (Au, Ag, Zr
etc.) have capability of differentiating members of the mycobacteria on the basis of gyrB locus.
In a nanodiagnostic technique unmodified spherical AuNPs can detect TB 16s rDNA specific oligo-targeters from clinical samples. This assay prototype can directly detect unamplified
Mycobacterium DNA using a single oligo-targeter (
Gazi et al., 2018). The prototype detection limit of this assay is 1 ng for PCR product and 40ng for genomic DNA. Scientists have proved that testing clinical specimens with the nano-gold assay prototype generated results are more sensitive to those obtained with using bacterial culture method and semi-nested PCR
(Hussain et al., 2013).
B. Based on modified nanoprobes
A cost-effective nanodiagnostic biosensor technique, that specific to TB diagnosis immobilize DNA probe and deposit it on nano-structured metal oxides Zirconia (ZrO2) film (crystallite size 35 nm). The nano-crystalline transparent ZrO2 is an attractive inorganic metal oxide with thermal stability, chemical inertness, non-toxicity and affinity for groups containing oxygen which facilitates covalent immobilization without using any cross-linker that may limit sensitivity of the fabricated sensor. The DNA-ZrO2 /Au is found to have stability as four months when stored at 4°C and detection limit of 0.065 ng/µl to target DNA concentration and 1 ng/µl of genomic DNA. This nanodianostic technique can be used for rapid and early detection of
M. tuberculosis (
Das et al., 2010).
In a novel nanodiagnostic strategy, the LAMP-AuNP probe method, showed no cross reaction with other mycobacteria and offered a short total assay time of <1 h. Scientists have proved that this assay is highly sensitivity, takes relatively shorter analysis time, cost effective and has lack of requirement for a thermocycler and separate detection reagents. Therefore, the LAMP-AuNP MTB probe assay constitutes a safe and simple alternative to traditional PCR for the rapid and sensitive detection of MTB DNA
(Kaewphinit et al., 2017).
3. Optical biosensor nanodiagnosis
A. Based on surface-enhanced raman scattering (SERS)
Scientists enable spectroscopic fingerprints of mycobacterial strains in few seconds using Raman spectroscopy. Recently more advanced surface-enhanced Raman scattering (SERS) technique that made of an array of silver nanoparticles imbedded in anodic aluminium oxide (AAO) in nanochannels
(Wang et al., 2006). The SERS-based diagnostic technique is applied to assess the fine structures of the bacterial cell wall and can detect single bacterium directly on clinical specimen instead of pure cultured bacteria
(Liu et al., 2009 and
Zhou et al., 2015).
B. Based on surface plasmon resonance (SPR)
In a surface plasmon resonance based nanodiagnostic technique
Mycobacterium specific antigens (
e.g., CFP-10 antigen) present in tissue fluid are visualized by binding to nanoparticles (
e.g. gold) on its optical sensor surface
(Bak et al., 2018). In this method, a monoclonal anti-CFP10 antibody is first immobilized on a commercially available immunosensor chip and then chip integrated with an SPR-based optical immunosensor system (BiaCore 3000, Sweden). This system utilizes the CFP10 antigen as a sensitive TB marker (
Hong et al., 2011). A linear relationship between SPR angle shift and values of CFP-10 concentrations are in the range from 0.1 to 1 µg/ml on SPR detection system. This newly developed and self-assembled SPR optical immunosensor system offers the advantages of simplicity of immobilization, low sample requirement, label-free, no pretreatment, high sensitivity, high specificity and high reusability. This is assumed that in future it will be used for home care and point-of-care in early diagnosis of TB.
4. Electrical conductive nanodiagnosis
In recent years tuberculosis furthermore get detected by electrical conductivity based different readout signals such as piezoresistive response, conductance change and voltammetry.
A. Piezoresistive based nanodiagnosis
The piezoresistive effect is a change in the electrical resistivity of semiconductor or metal when mechanical strain is applied. In Piezoresistive based nanodiagnosis a nanocantilever device is used to detect
Mycobacterium. The specific TB antibodies against antigen 85 complex are immobilized on upper surface of cantilever. A cantilever device is a spring board where after antigen capture spring board bend and facilitate presence of TB by measuring the capacitance and resonant frequency in attached micromechanical biosensors. The micromechanical biosensors work as standard silicon technology in these nanocantilevers. The electrostatically actuated and intrinsic flexibility allow nanocantilever for biomolecular recognition in low cost (
Sangeetha and Juliet 2013).
In a piezoresistive based nanodiagnostic technique Quartz crystal microbalance (QCM) biosensor combined with gold nanoparticle is used to detect
Mycobacterium. In this diagnostic technique QCM sensing surface is immobilized with anti-MTB antibodies. This sensing surface capture MTB from clinical sample, after capturing mycobacteria the frequency shift made due to change in mass loading on sensor is monitored in real time with detection limit of 105 CFU/ml (
He and Zhang 2002). Although this diagnostic technology is rapid, simple and label-free, its accuracy is affected by a number of factors such as density, viscosity, dielectric constant and electrical conductivity of the sample
(Ren et al., 2008).
B. Based on conductance change
In a conductance change based nanodiagnostic technique, scientists developed to detect different protein biomarkers of
Mycobacterium antigens and ssDNA that specific for tuberculosis forming
Mycobacterium. The nanodiagnostic tool is made on a microchip-like set up where the nanowire/nanotubes (both single and multi-walled) are fixed along with surface functionalization
i.e. antibodies or antigens, depending on the samples to be used. The cost effective nano-sized built biosensors operate as field effect transistors (FETs) with very low detection limit such as for IFN-γ it is found to be 83 pg /ml
(Farid et al., 2015 and
Carolina et al., 2016).
C. Based on different pulse voltammetry
In a nanodiagnostic technique based on different pulse voltammetry tuberculosis can diagnose in milk sample. In this method antigen specific of monoclonal antibodies are immobilize on alkaline phosphatise labelled goat antimouse chitosan glassy carbon electrode layered with nano-modified gold film. The change in incubation, before and after reaction on electrode due to capture of bacterial antigen by monoclonal antibody are quantitatively analyze and measure by mechanized system. The detection method is simple with high sensitivity, short detection time, simple operation and rapid detection of mycobacteria
(Wei et al., 2013).
A different pulse voltammetry based nanodiagnostic technique is used to detect
Mycobacterium DNA on colloidal gold nanoparticles that attached to disposable screen printed carbon electrode. This assay system is coupled to rapid isothermal amplification of target specific to mycobacterial DNA. The assay is capable of detecting positive different pulse voltammetry (DPV) response as low as 1 CFU of mycobacterial DNA input material which is exquisite sensitive over conventional gel based readout. This bioassay is simple, rapid and sensitive
(Ng et al., 2015).
5. Nuclear magnetic resonance (NMR) nano-diagnosis
A. Based on diagnostic magnetic resonance (DMR)
In the diagnostic magnetic resonance based nanodiagnostic technique
Mycobacterium organism can be detected in unprocessed clinical sample within 30 minutes (
Kaittanis et al., 2007 and
Lee et al., 2008). In this nanodiagnostic device targeted
Mycobacterium responsible for tuberculosis get hybridized with superparamagnetic iron oxide nanoprobes and then they concentrated into a microfluidic chamber, here hybridized magnetic nanoprobes detected by nuclear magnetic resonance
(Lee et al., 2009). These captured functionalized magnetic nanoparticles are used with highly sensitive (20 CFU /ml) magnetic measurements. This can specifically detect the
Mycobacterium in unprocessed samples without sample pre-treatment for early cost effective diagnosis
(Srivastava et al., 2016).
B. Based on magnetic barcode platform
The nanodevice magnetic barcode platform has been developed for the sensitive and robust diagnosis of TB. In this diagnostic technique PCR amplified mycobacterial genes sequence is specifically captured on microspheres, labelled by magnetic nanoprobes and then detected by nuclear magnetic resonance
(Srivastava et al., 2016). All components are integrated into a single, small fluidic cartridge for streamlined on-chip operation. This nanodiagnostic platform can detect TB and can also identify drug-resistant strains from mechanically processed clinical samples within 2.5 hours. Combined with portable systems, the magnetic barcode assay holds promise to become a sensitive, high-throughput and low-cost platform for point-of-care diagnostics
(Liong et al., 2013 and
Chen et al., 2018).
6. Nano-fabricated devices
Recently nano-fabricated devices show its diagnostic potential in relatively reduced costs. Moreover, these platforms demonstrate the most promising trends in bioanalytical and biochemical methods, the fusion of different approaches, methods and technologies into a single platform.
A. Based on electro-immunosensors
Most recently researchers have developed TB diagnosis based on Nanofabricated biomicrosystems. This development validates a non-invasive method to electrically monitor the assembly process of electro-immunosensors. The miniaturized biosensing platform can detect ESAT-6 antibody using Physical Vapour Deposition (PVD) of 80 nm Au nanolayers on 35 µm copper surfaces by impedance analysis in about 1 h of analysis time. The technology is used to optimize the time, cost and replicability of the fabrication in TB diagnosis
(Sepulveda et al., 2017).
B. Based on optical colorimetric detection method
This nanofabricated diagnostic platform is designed by replica moulding technology in a polydimethylsiloxane (PDMS) device patterned by high-aspect-ratio SU-8 moulds. The nanofabricated microfluidic platform can sense mycobacterial DNA by an optical colorimetric detection method using gold nanoparticles. The platform is disposable, low cost, bio-microfluidic chip with optical fibres. This non-disposable host device, integrates light sources, photo-detectors and electronic equipments. This biochip can detect
Mycobacterium DNA using only 3 µl DNA solution (
i.e. 90 ng of target DNA),
i.e. 20-fold reduction of reagents volume in compare to other diagnostic assay
(Wojcik et al., 2013).
C. Based on electrochemical biosensors
In a nanodiagnostic electrochemical biosensor, a sandwich detection strategy involves two kinds of DNA probes specific to tuberculous
Mycobacterium genomic DNA (probes of enzyme ALP and the detector probe). The sandwiched device involves both the probes conjugated on the AuNPs and subsequently hybridized with target DNA and is immobilized on a SAM/ITO electrode. The effect of enhanced sensitivity obtained due to the AuNPs carrying numerous ALPs per hybridization with a detection limit of 1.25 ng/ml genomic DNA under optimized conditions. The dual-labeled AuNP-facilitated electrochemical sensor using clinical samples shows high sensitivity and specificity. This diagnostic assay can be employed as a regular diagnostic tool for
Mycobacterium sp. monitoring in clinical samples
(Thiruppathiraja et al., 2011).
D. Lab on chip
Lab-on-Chip (LoC) devices integrates biochemical operations, chemical synthesis, DNA sequencing onto a single chip which otherwise would have been performed in laboratory taking sufficient amount of time. Due to the miniaturization of these biochemical operations, better diagnostic speed, cost efficiency, ergonomy, sensitivity and so on can be achieved. Cabibbe and coworker evaluated the performance of the molecular lab-on-chip-based VerePLEX Biosystem for detection of tuberculosis, obtaining a diagnostic accuracy of more than 97.8 per cent compared to sequencing and MTBDR
plus assay on clinical isolates and smear-positive specimens. The high speed, user-friendly interface, and versatility make it suitable for routine laboratory use
(Cabibbe et al., 2015).
E. Sparse cell detection nanodiagnosis
Sparse cells are both rare and physiologically distinct cells from their surrounding cells in normal physiological conditions. The technique takes advantages of the unique properties of sparse cells manifested in differences in deformation of intracellular TB bacilli
(Fakruddin et al., 2012). On inserting electrodes into microchannels, sparse cell accurately identify by their surface charge. These can also be sorted by using biocompatible surfaces with precise nanopores. The nano-biotechnology centre at Cornell University (NBTC) is currently using these technologies to develop powerful diagnostic tools for the isolation and diagnosis of tuberculosis (
Mithra and Emmanuel 2017).
lV. Advantages of nanodiagnosis for tuberculosis
Nanotechnology has introduced new paradigms for molecular diagnostics. It provides diagnosis within hours, with increased sensitivity, specificity and low cost when compared to conventional microbiological and other molecular biology methodologies
(Veigas et al., 2012).
A nanotechnology-based TB diagnostic kit, designed by the Central Scientific Instruments Organization Chandigarh, India is currently in clinical trials. This kit does not require skilled technicians for the use and offers efficiency, portability, user-friendliness and approximately only Rs.30 per test (Alharbi and Al-Sheikh 2014). Some other important advantages of nanaodiagnosis are as follow:
1. This provides new platforms for multiplexed immunoassays and high-throughput protein arrays in TB diagnosis.
2. DNA-labeled magnetic nanobeads have the potential to serve as a versatile foundation in TB diagnosis.
3. Rapid detection and accurate quantification of TB biomarkers, even they are present at very low concentrations and also in small sample volumes.
4. Helps in clinical decision-making, treatment cost and improves the chances of cure.
5. Nanotechnology will facilitate the development of personalized medicine,
i.e. prescription of specific therapeutics best suited for an individual.
6. The use of nanodianosis shows great promise to meet the rigorous demands of the clinical laboratory for sensitivity and cost-effectiveness.
V. Constraints of nanodiagnostic technology
Nanoparticles have potentially toxic effect when it is used in vivo but
in vitro diagnostic tool which forms the major portion of laboratory diagnostics are extempted from these toxic effect. However, some constraints of nanodiagnostic tool still there that make obstacle in its worldwide diagnostic use for TB. The major problems are as follow:
1. Environmental concerns about the release of nanoparticles during manufacturing of nanoparticles. The nanoparticle spreaded in environmental acquire serious hazard and are found an obvious concern for the use of these minaturised nanodiagnostic tools.
2. The cast off nanodevices or nanoparticles used in diagnosis exposure to stray animals and environment may create biohazardous waste.
3. The regulatory process involving approval of nanodiagnostic assays and tests is often slow with the complexity.
