Substrate Report for: Myristoylcholine

Enzyme-responsive, amphiphilic self-assembly represents one of the increasingly significant topics in biomaterials research and finds feasible applications to the controlled release of therapeutic agents at specific sites where the target enzyme is located. The supramolecular approach, using "superamphiphiles", provides a smart way to fabricate drug delivery systems responsive to enzymatic catalysis. In this work based on the concept of supramolecular chemistry, we report an enzyme-responsive vesicle using p-sulfonatocalix[4]arene as the macrocyclic host and natural enzyme-cleavable myristoylcholine as the guest molecule. The complexation of p-sulfonatocalix[4]arene with myristoylcholine directs the formation of a supramolecular binary vesicle, which is dissipated by cholinesterase with high specificity and efficiency. Cholinesterase is a key protein overexpressed in Alzheimer's disease, and therefore, the present system may have potential for the delivery of Alzheimer's disease drugs.

We have fabricated enzyme responsive polymeric supra-amphiphiles by mixing a block copolymer of poly(ethylene glycol)-block-poly(acrylic acid) with myristoylcholine chloride in water. The polymeric supra-amphiphiles self-assemble into spherical aggregates with sizes varying from about 40 to 150 nm. Moreover, the spherical aggregates can be disassembled triggered by acetylcholinesterase, an enzyme which can cut off the ester linkage of myristoylcholine chloride. Nile red can be loaded into the spherical aggregates and released in several hours upon the treatment of acetylcholinesterase. The releasing rate is rather fast considering that it takes more than 150 h for Nile red to diffuse out of the spherical aggregates without addition of acetylcholinesterase. It is anticipated that the new enzyme responsive polymeric supra-amphiphile may be explored as a carrier for drug delivery.

A complex between an anionic polythiophene derivative (PT-COO(-)) and a cationic surfactant, myristoylcholine, has been prepared and applied to be colorimetric probe for acetylcholinesterase (AChE) assays. The complex formation process, AChE activity assay and inhibitor screening has been studied by absorption spectroscopy. It was confirmed that the introduction of myristoylcholine into PT-COO(-) phosphate buffer solution resulted in the disassembly of PT-COO(-) aggregates, and further addition of AChE into the above solution led to the reassembly of PT-COO(-) due to the catalyzed hydrolysis of myristoylcholine and the collapse of the complex. The colorimetric assay for AChE can be readily realized with the concentration of AChE as low as 0.2 U/mL. The results also demonstrate that the colorimetric approach can be applied for screening inhibitors of AChE.

Enzyme-responsive, amphiphilic self-assembly represents one of the increasingly significant topics in biomaterials research and finds feasible applications to the controlled release of therapeutic agents at specific sites where the target enzyme is located. The supramolecular approach, using "superamphiphiles", provides a smart way to fabricate drug delivery systems responsive to enzymatic catalysis. In this work based on the concept of supramolecular chemistry, we report an enzyme-responsive vesicle using p-sulfonatocalix[4]arene as the macrocyclic host and natural enzyme-cleavable myristoylcholine as the guest molecule. The complexation of p-sulfonatocalix[4]arene with myristoylcholine directs the formation of a supramolecular binary vesicle, which is dissipated by cholinesterase with high specificity and efficiency. Cholinesterase is a key protein overexpressed in Alzheimer's disease, and therefore, the present system may have potential for the delivery of Alzheimer's disease drugs.

We have fabricated enzyme responsive polymeric supra-amphiphiles by mixing a block copolymer of poly(ethylene glycol)-block-poly(acrylic acid) with myristoylcholine chloride in water. The polymeric supra-amphiphiles self-assemble into spherical aggregates with sizes varying from about 40 to 150 nm. Moreover, the spherical aggregates can be disassembled triggered by acetylcholinesterase, an enzyme which can cut off the ester linkage of myristoylcholine chloride. Nile red can be loaded into the spherical aggregates and released in several hours upon the treatment of acetylcholinesterase. The releasing rate is rather fast considering that it takes more than 150 h for Nile red to diffuse out of the spherical aggregates without addition of acetylcholinesterase. It is anticipated that the new enzyme responsive polymeric supra-amphiphile may be explored as a carrier for drug delivery.

A complex between an anionic polythiophene derivative (PT-COO(-)) and a cationic surfactant, myristoylcholine, has been prepared and applied to be colorimetric probe for acetylcholinesterase (AChE) assays. The complex formation process, AChE activity assay and inhibitor screening has been studied by absorption spectroscopy. It was confirmed that the introduction of myristoylcholine into PT-COO(-) phosphate buffer solution resulted in the disassembly of PT-COO(-) aggregates, and further addition of AChE into the above solution led to the reassembly of PT-COO(-) due to the catalyzed hydrolysis of myristoylcholine and the collapse of the complex. The colorimetric assay for AChE can be readily realized with the concentration of AChE as low as 0.2 U/mL. The results also demonstrate that the colorimetric approach can be applied for screening inhibitors of AChE.

A new convenient and continuous fluorometric assay method for acetylcholinesterase (AChE) and its inhibitor screening is successfully established with the ensemble of 1 [a TPE (tetraphenylethylene) compound with two sulfonate (-SO(3)(-)) units] and myristoylcholine (an amphiphilic compound as a good substrate of AChE). This new assay method is designed by making use of the aggregation-induced emission (AIE) feature of TPE compounds. Both dynamic light scattering (DLS) and fluorescence confocal microscopic measurements indicated the formation of aggregation complex for the ensemble of 1 and myristoylcholine and further disassembly of the aggregation complex after introducing AChE. The analysis for AChE can be carried out continuously, and AChE with concentration as low as 0.5 U/mL can be assayed. The results also clearly demonstrate the usefulness of this convenient assay method for kinetic study of AChE-catalyzed myristoylcholine hydrolysis and screening inhibitors of AChE. Given its simplicity and easy operation, this method may extend to high-throughput screening of AChE inhibitors and relevant Alzheimer's disease (AD) drug discovery.