This article describes the preparation of nerve growth factor (NGF) loaded HDL-mimicking nanoparticles using protamine as a carrier protein. The method involves the encapsulation of NGF in lipid-based nanoparticles to enhance its stability and bioactivity.
Take a microcentrifuge tube containing nerve growth factor or NGF, a neurotrophic protein, and protamine, a positively charged carrier protein.
Protamine complexes with NGF via electrostatic interactions that facilitate encapsulation and prevent degradation.
To a glass vial, add ethanol containing lipid excipients that mimic the lipid composition of high-density lipoproteins or HDL for nanoparticle formation.
Mix with additional ethanol for uniform dispersion. Evaporate ethanol under nitrogen to form a thin lipid film.
Add ultrapure water and homogenize at high speed to allow self-assembly into HDL-mimicking prototype nanoparticles.
Introduce the NGF-protamine complex into the nanoparticles and incubate while stirring to promote encapsulation of NGF-protamine while preserving their bioactivity.
Cool the suspension for nanoparticle stabilization, then add Apolipoprotein A-I, the primary structural protein of HDL, and continue stirring to integrate the protein into the nanoparticle structure.
These NGF-loaded HDL-mimicking nanoparticles are now ready for further studies.
To begin, mix 10 microliters of NGF with 10 microliters of protamine USP in a 1.5 milliliter microcentrifuge tube, and let it stand for 10 minutes at room temperature to form the complex. Next, add 59 microliters of phosphatidylcholine and 11 microliters of sphingomyelin to a glass vial.
Also add 4 microliters of phosphatidylserine, 15 microliters of cholesterol oleate, and 45 microliters of tocopheryl polyethylene glycol succinate. Mix and evaporate the ethanol under a gentle nitrogen stream for about five minutes. All excipients should form an oily, thin film at the bottom of the glass vial.
Add 1 milliliter of ultrapure water to the vial, and homogenize at 9,500 RPM for 5 minutes at room temperature to form the prototype nanoparticles or NPs. Then, add the prepared complex to the prototype NPs. Incubate the suspension at 37 degrees Celsius for 30 minutes, with stirring, by using a small stirring bar in the glass vial.
Cool the MPs down by stirring at room temperature for another 30 minutes. After cooling, add 106 microliters of apolipoprotein A-I and stir at room temperature overnight to form the final NGF HDL mimicking NPs.
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