Low-intensity, kilohertz frequency spinal cord stimulation differently affects excitatory and inhibitory neurons in the rodent superficial dorsal horn

In a typical competitive lateral flow immunoassay (LFI), the signal intensity decreases as the concentration of target increases, affecting sensitive and quantitative detection of target molecules.To overcome this limitation, a trapLFI was previously developed by us; it can detect small molecules, such as cortisol, with high sensitivity quantitative analysis by lowering the amount of gold nanoparticle -antibody conjugate and carrying out additional enzyme catalytic signal enhancement steps compared with those of the LFI.However, a limitation with this method is that the additional signal enhancement steps should be carried out manually 10 min after sample solution injection to the sensor.An advanced trapLFI (␣-trapLFI) developed in this study allows an additional step for signal enhancement consecutively performed with sample solution injection, making it more user-friendly than previous methods.For signal enhancement, a polyvinyl alcohol (PVA) tape was used, which has the delayed release property of solutions.The PVA tape, located between conjugate pad and immune reaction part, releases gold ions from the signal enhancement pad for signal enhancement after a certain time of immune reaction.Because of the delayed release effect of PVA tape, the signal enhancement step was successfully accomplished with consecutive loading of sample and enhancement solutions.So, the end-user does not have to perform additional steps.Furthermore, by employing cortisol as a model we successfully demonstrated that the advanced trap lateral flow immunoassay sensor can be utilized to detect cortisol in saliva with high sensitivity (9.1 pg mL -1 ) and a broad detection range (0.01-1000 ng mL -1 ).The serum and urine samples showed results similar to those of saliva samples.Furthermore, analysis of 20 human saliva samples showed a good correlation with conventional ELISA results (R 2 = 0.90).The developed sensor can be applied to detect all kinds of small molecules without any difficulty, owing to its simplicity and high sensitivity.