Rongalite, dopamine hydrochloride and resorcinol were purchased from Macklin Company (Shanghai, China). Formaldehyde solution (37–40%) was obtained from J &K Scientific (Beijing, China). Glucose, sucrose, glutamate, prolamin and Ca2+ were supplied by Aladdin Industrial Corporation (Shanghai, China). Sodium carbonate, sodium hydroxide and hydrochloric acid were purchased from Sinopharm Chemical Reagent Co., Ltd. (Beijing, China). All the reagents were analytical grade.
Sterile syringe filters (0.45 μm) were obtained from Merck (Merck Millipore, Burlington, MA, USA). White opaque microplates were supplied by Corning Ltd. (Corning Life Science, Hartford, NY, USA). Ultra-pure water was used in all aqueous solution and was produced by Millipore purification system (MilliQ gradient A10, Millipore, Bedford, MA, USA). Fluorescence excitation and emission spectra, absorption spectra, optical density, and fluorescence intensity were measured using a microplate reader (SpectraMax M2e, Molecular Devices, San Jose, CA, USA). The pH values were measured by a pH meter supplied by Thermo Fisher Scientific Inc. (Orion 4 Star, Beverly, MA, USA). The mass spectrum analysis was performed on the electrospray ionization (ESI)-TRIPLE QUAD 5500 (AB SCIEX, Framingham, MA, USA.) in the negative ion mode.
Sterile syringe filters (0.45 μm) were obtained from Merck (Merck Millipore, Burlington, MA, USA). White opaque microplates were supplied by Corning Ltd. (Corning Life Science, Hartford, NY, USA). Ultra-pure water was used in all aqueous solution and was produced by Millipore purification system (MilliQ gradient A10, Millipore, Bedford, MA, USA). Fluorescence excitation and emission spectra, absorption spectra, optical density, and fluorescence intensity were measured using a microplate reader (SpectraMax M2e, Molecular Devices, San Jose, CA, USA). The pH values were measured by a pH meter supplied by Thermo Fisher Scientific Inc. (Orion 4 Star, Beverly, MA, USA). The mass spectrum analysis was performed on the electrospray ionization (ESI)-TRIPLE QUAD 5500 (AB SCIEX, Framingham, MA, USA.) in the negative ion mode.