## 2 Applications of Biosensors in Bacteria Detection
### Recognition of Bacteria Using Biosensors
#### 2.1.3 Electrochemical Biosensors
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Biosensor Type** & **Detected Bacteria** & **Limit of Detection** & **Assay Time** & **Ref.** \\ \hline Electrochemical & _E. coli_ & \(10^{3}\) CFU/mL & 30 min & [PERSON] et al. [127] \\ \hline Sandwich-type electrochemical biosensor * & _E. coli O157:H7_ & 32 CFU/mL & 120 min & [PERSON] et al. [159] \\ \hline All-electronic complementary & _Gram-positive_ and & & & \\ metal oxide semiconductor (CMOS) biosensor & _Gram-negative bacteria_ & \(10^{7}\) CFU/mL & 25 min & [PERSON] et al. [160] \\ \hline Ultrasensitive nanophotonic & & & & \\ bimodal waveguide & _Gram-negative bacteria_ & (28 aM) & 30 min & [PERSON] et al. [161] \\ \hline Lectin-conjugated porous & _E. coli_ and _S. aureus_ & \(10^{3}\) cells/ mL & No data & [PERSON] et al. [100] \\ \hline Bimodal waveguide & _P. aeruginosa_ and _methhicillin-resistant_ & 49 and 29 CFU/mL (theoretical LOD) & 12 min & [PERSON] et al. [101] \\ \hline High-throughput aptamer based & & & & \\ photo-irradiation colorimetric biosensor * & _S. aureus_ & 81 CFU/mL & 5.5 h & [PERSON] et al. [51] \\ \hline Fluorescent supramolecular & _E. coli_ & \(10^{5}\) CFU/mL & No data & [PERSON] et al. [56] \\ \hline Portable fluorescent biosensing * & _E. coli O157:H7_, _L. monocytogenes_, _S. typhimurium_ & \(10^{2}\), \(10^{3}\), and \(10^{3}\) CFU/mL & 60 min & [PERSON] et al. [53] \\ \hline Fluorescent magnetic biosensor & _E. coli O157:H7_ & 1.57 CFU/ mL & 1.5 h & [PERSON] et al. [50] \\ \hline Graphene-DNAzyme-based fluorescent biosensor * & _E. coli_ & \(10^{5}\) CFU/mL & 4 h & [PERSON] et al. [55] \\ \hline Aptamer-based fluorescent biosensor * & _S. somei_ & \(10^{3}\) CFU/ mL & No data & [PERSON] et al. [54] \\ \hline Optical biosensor with & _L. monocytogenes_ & \(10^{2}\) CFU/mL & No data & [PERSON] et al. [162] \\ \hline Fluorescent biosensor * & _E. coli O157:H7_ & 14 CFU/mL & 2 h & [PERSON] et al. [52] \\ \hline Quantum dot nanobead-based biosensor * & _S. typhimurium_ & \(5\times 10^{3}\) CFU/mL & 10 min & [PERSON] et al. [163] \\ \hline Nanobisensor (AuNRS based sensor) * & _E. coli_, _P. aeruginosa_ & \(10^{9}\) to \(10^{6}\) CFU/mL (measured concentrations) & No data & [PERSON] et al. [82] \\ \hline Graphene field effect transistors & _S. aureus_, colististin resistant_ & \(10^{4}\) CFU/mL (_S. aureus_), (_S. aureus_), & 5 min & [PERSON] et al. [164] \\ (G-FET) & _A. humammili_ & \(10^{5}\) CFU/mL (_A. humammili_) & & \\ \hline Colorimetric biosensor & & 12 CFU/mL (both samples), & & \\ (paper-based magnetic nanoparticle-peptide probe) * & & 30-300 CFU/mL (spiked complex food matrices) & 30 s & [PERSON] et al. [60] \\ \hline Colorimetric paper-based biosensor * & _S. aureus_ (_L. monocytogenes19115_, _E. coli O157:H7, MRSA, C. A. albicans_ & 7 CFU/mL (inoculated in food produces) 100 CFU/mL (environmental samples) & \\ _P. aeruginosa_ 15692) & & \(10^{3}\) CFU/mL (visual observation) & & \\ Optical immunoassay sensor * & bacteria (_E. coli_, _S. aureus_ and _S. epidermidis_) & 29 CFU/mL (linear regression equation) & 5 min & [PERSON] et al. [58] \\ \hline Colorimetric biosensor (using & _P. aeruginosa_ & \(10^{2}\) CFU/mL & \(<\)1 min & [PERSON] et al. [59] \\ magnetic nanoparticles) * & _L. monocytogenes_ & \(2.17\times 10^{2}\) CFU/mL & \(<\)1 min & [PERSON] et al. [61] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._sor units, and thus high-throughput monitoring capabilities [165; 166; 167; 168; 169]. Usually, optical biosensors are less sensitive to vibration and electrical noise. The disadvantage of the evanescent field-based methods is that if the sample does not reach the evanescent field (approximately a 100-150 nm thick layer above the sensing surface), there is no biosensor signal at all [165; 166; 170], therefore, sample concentration is sometimes critical.