Pa Synthesis Lab Report

Materials & Methods Synthesis Procedure of PDA@MT Polydopamine is synthesized through covalent polymerization similar to melanin biosynthesis, with DA oxidized to dopamine quinone, then further oxidized to DHI, which undergoes deprotonation and cross-linking via Michael addition to form PDA. A solution was prepared to synthesize PDA by mixing 90 mL of water, 40 mL of ethanol, and 3 mL of ammonia solution in a 300 mL beaker. After stirring for 30 minutes at 37°C, a solution of 500 mg of DA dissolved in 10 mL of water was added dropwise using a pipette while stirring at 400 rpm. The reaction was continued for 24 hours at 300 rpm, and the particle size was monitored by taking a sample at 12-24 hours and diluting it with water. The reaction product
Particle size and UV quantification were measured by diluting the PDA water solution and measuring the UV absorbance. MT was loaded onto the surface of PDA through hydrophobic interactions, - conjugation, and electrostatic interactions. A 500 L, 1 mg/mL MT solution was added to a 1 mL, 1 mg/mL PDA solution. After stirring at 400 rpm for 12 hours, unbound MT was removed by centrifugation and washing, resulting in the formation of PDA@MT. Evaluation of encapsulation efficiency and loading capacity Encapsulation efficiency and loading capacity were determined using the differential method. 5 mg of MT standard substance was weighed and dissolved in ultra-pure water to prepare the standard curve. The resulting solution was transferred to a 5 mL volumetric flask to prepare a 1 mg/mL DEX solution, which was then further diluted to prepare standard solutions of 5, 6.25, 10, 12.5, and 20 g/mL. The absorbance at 242 nm was measured using a UV-2600i spectrophotometer, and a standard curve was plotted with the concentration as the abscissa and absorbance as the ordinate. Next, the solution below and above the ultrafiltration membrane was collected, and the volume was
They were then co-incubated with different nanoparticles for 4h. After removing the culture medium, the cells were incubated with a diluted DCFH-DA reactive oxygen species (ROS) probe for 20 minutes and observed under a microscope after washing away the staining solution. Evaluation of in vitro therapeutic effect of human tracheal epithelial cells, HTEpiC, were procured from the Cell Bank of the Chinese Academy of Sciences in Shanghai. These cells were grown in a specialized culture medium and exposed to an intermittent hypoxia (IH) model. In this model, the cells were placed in a hypoxia chamber at 37°C and 5% CO2, with oxygen levels alternating between 1% and 21% every 8 minutes and 4 minutes, respectively. The cells were subjected to IH for a total of 12 hours, consisting of 60 cycles. Following this, the model cells were co-incubated with various nanoparticles for 4 hours, and the CCK-8 assay was used to detect changes in cell viability. Subsequently, the cells were co-incubated with different concentrations of PDA@MT for 4 hours and then stained using a live/dead staining kit to assess the effect of varying nanoparticle concentrations on cell