Biosensors for the Detection of Bacillus anthracis

Abstract

Conspectus Bacillus anthracis, present in two forms of vegetative cells and spores, is a pathogen that infects humans through contact with infected animals or contaminated animal products and is also maliciously used in terrorist acts. Therefore, a rapid and sensitive test for B. anthracis is necessary but challenging. The challenge comes from the following aspects: an accurate distinction of B. anthracis from other Bacillus species due to their high genomic similarity and the horizontal gene transfer between Bacillus members; direct detection of the B. anthracis spores without damaging them for component extraction to avoid the risk of spore atomization; and the rapid detections of B. anthracis in complex samples, such as soil and suspicious powders, without sample pretreatments and expensive large-scale equipment. Although culturing B. anthracis from samples is the conventional method for the detection of B. anthracis, it is time-consuming and the detection results would not be easy to interpret because many Bacillus species share similar phenotypic features such as a lack of motility and hemolysis, resistance to gamma phages, and so on. Intensive and extensive effort has been expended to develop reliable detection technologies, among which biosensors exhibit comprehensive advantages in terms of sensitivity, specificity, and portability. Here, we briefly review the research progress, providing highlights of the latest achievements and our own practice and experience. The contents can be summarized in three aspects: the discovery of detection targets, including genes, toxins, and other components; the creation of molecular recognition elements, such as monoclonal antibodies, single-chain antibody fragments, specific peptides, and aptamers; and the design and construction of biosensing systems by the integration of appropriate molecular recognition elements and transducer devices. These sensor devices have their own characteristics and different principles. For example, the surface plasmon resonance biosensor and quartz crystal microbalance biosensor are very sensitive, while the multiplex PCR-on-a-chip can detect multitargets. Biosensors for direct spore detection are highly recommended because they are not only fast but also avoid contamination from aerosol-containing spores. The introduction of nanotechnology has significantly improved the performance of biosensors. Superparamagnetic nanoparticles and phage-displayed gold nanoparticle ligand peptides have made the results of spore detection visible to the naked eye. Because of space constraints, many advanced biosensors for B. anthracis are not described in detail but are cited as references. Although biosensors provide a variety of options for various application scenarios, the challenges have not been fully addressed, which leaves room for the development of more advanced and practical B. anthracis detection means.

Anthrax revisited: how assessing the unpredictable can improve biosecurity

“…These methods require highly trained laboratory personnel, BSL-3 facilities, and practices. Novel detection methods are based on diverse targets, from detection based on DNA ( Pal and Alocilja, 2010 ; Hao et al, 2011 ; Kaittanis et al, 2011 ; Chen et al, 2020 ), chemical reactions ( Boyer et al, 2007 ; Duriez et al, 2009 ; Čapek et al, 2010 ; Kuklenyik et al, 2011 ), antibodies ( De et al, 2002 ; Biagini et al, 2006 ; Campbell and Mutharasan, 2006 ; McGovern et al, 2007 ; Hao et al, 2009 ; Mwilu et al, 2009 ; Tang et al, 2009 ; Zahavy et al, 2010 ; Wang, 2013 ; Atabakhshi-Kashi et al, 2020 ), phages ( Schuch et al, 2002 ; Fujinami et al, 2007 ), peptides ( Acharya et al, 2007 ; Park et al, 2009 ), aptamers ( Alibek and Handelman, 1999 ; Huan et al, 2009 ; Cella et al, 2010 ; Oh et al, 2011 ; Kim et al, 2013 ) or even DNA-peptide chimeras ( Zhang and Appella, 2007 ; Kim et al, 2015 ; Wang D-B. et al, 2021 ).…”

A luminescent terbium(iii) probe as an efficient ‘Turn-ON’ sensor for dipicolinic acid, a Bacillus Anthracis biomarker

“…The organic solvents used for synthesis and spectroscopic studies were either of HPLC grade or purified by some standard protocols. 1 H, 13 C, and 31 P NMR (chemical shifts in d ppm) spectral characterization and titration studies were performed on a JEOL FT-NMR (400 MHz) spectrometer in DMSO-d 6 at 298 K, where TMS has been used as an internal standard. ESI-MS measurements were carried out by using a Waters QTOF premier mass spectrometer in DMF solvent.…”

“…12 However, other detection methods involve GC-MS, HPLC, SPR, or the use of biosensors, nanosensors, electrochemical or optical sensors. [13][14][15][16][17][18][19] In the present study, we have explored the luminescence methods by utilizing lanthanidebased optical probes that could offer a rapid, highly selective, sensitive, and inexpensive detection platform for anthrax spores. The dipicolinic acid (DPA) as calcium dipicolinate (CaDPA) is a major component of these bacterial endospores and is not found in other bacterial spores in the environment.…”