Biomolecules of the Horseshoe Crab’s Hemolymph: Components of an Ancient Defensive Mechanism and Its Impact on the Pharmaceutical and Biomedical Industry

Table 6

Endotoxin detection biosensor and their features.

Endotoxin detection biosensor	Features of the biosensor
(1) Endotoxin-induced Limulus amebocyte lysate gel-clot process	(1) Electrochemical behavior of the sensor has already been studied. For the electrochemical examination, screen-printed electrodes with excellent stability, easy operation, and low cost are developed [100].; (2) The electrochemical signals of the gel-clot process are then applied to the endotoxin assay [101].; (3) The LAL contained zymogens that were activated by an endotoxin to produce p-nitroaniline (pNA), which was then electrochemically measured by differential pulse voltammetry (DPV). Within an hour, this chip device could detect endotoxins with as few as 10 units/l at ambient temperature. This method has been shown to improve the LAL assay sensitivity by 200 times compared to the commercial standard methods, reduce the assay time by more than half, and eliminate the need to incubate the test samples [102].
(2) A unique open-microcavity photonic-crystal biosensor	(1) To monitor the change in the refractive index due to the reaction between LAL regents and endotoxins.
(3) A nanoplasmonic biosensing method	(1) In the pharmaceutical industry, a nanoplasmonic biosensing method for endotoxin detection has previously been developed [103].
(4) Highly sensitive endotoxin assays using DNA-modified gold nanoparticles and peptide/graphene oxide	(1) This sensor can detect as little as 0.001 EU ml^-1. Additionally, this technique has been effectively used to assess endotoxins in complicated biological samples, which may have a lot of potential applications [104].