Ultrasensitive Acetylcholinesterase detection based on a surface-enhanced Raman scattering lever strategy for identifying nerve fibers.

Accurate discriminating nerve fibers is a prerequisite for right suturing nerves in nerve transfer operation. Various methods have been developed for identification of motor and sensory fibers, but no simple method meets the requirements in clinic. In this study, a surface-enhanced Raman scattering (SERS) lever strategy is designed and developed to detect Acetylcholinesterase (AchE) ultrasensitively, in which using produced thiocholine with weak intrinsic Raman activity (four ounces) to adjust absorbance of Rhodamine B with strong intrinsic Raman activity (thousand catties) on SERS-active substrates is to increase the sensitivity. Employing a miniaturized SERS substrate, SERS-active microneedles, is to decrease the volume of enzymolysis systems. Adopting an internal reference is to increase the repeatability of collected signal. The ultrasensitive AchE detection method discriminate samples with four times of difference in enzyme activity between 1-1 × 10 U/mL in about 10 min of enzymolysis time. AchE amounts in 2-mm-long segments of ventral and dorsal roots were about 0.00025-0.001 U and 0.01-0.02 U, respectively. The developed method would be a reliable method met the requirements of identifying motor and sensory fibers in clinic.