The usage method of the hand pushed liposome extruder can be divided into the following steps, summarized as follows based on the operating points and precautions:
1、 Preparation before operation
1. Component inspection and pre-processing
Check whether the O-ring is worn, and replace the original parts if necessary to avoid pressure relief risks.
Thoroughly clean the extruder components (such as membranes and micro orifice plates), it is recommended to use ultrasonic cleaning and pre squeeze with pure water multiple times to ensure smooth channels.
The polycarbonate film needs to remove the blue protective film and only retain the white film. During installation, soak the sample to avoid bubbles affecting extrusion efficiency.
2. Sample pretreatment
If the liposome suspension contains large particles or aggregates, it is recommended to first reduce the particle size through homogenization treatment to avoid clogging the filter membrane.
Ensure that the sample is evenly dispersed to reduce the risk of precipitation.
2、 Operation steps
1. Assembly and Sampling
Install the filter membrane combination according to the "sandwich structure" (such as polycarbonate membrane+auxiliary filter membrane).
Load the preprocessed sample into an airtight glass syringe, connect the extruder chamber, and ensure that it is inserted all the way through the needle opening before gently tightening and fixing it.
2. Extrusion operation
First extrusion: Slowly and evenly push the plunger of the syringe, keeping the direction of force consistent with the axis of the syringe, so that the sample flows through the filter membrane to the empty syringe on the other side.
Multiple squeezes: After completion, switch the positions of the syringes on both sides and repeatedly push to achieve multiple squeezes (usually 3-10 times) until the requirement of uniform particle size is reached.
Temperature control requirement: If constant temperature operation is required, the entire equipment can be placed in a hot water bath.
3、 Precautions
1. Operating standards
Maintain even force throughout the entire process to avoid directional deviation that may cause the syringe to break or leak.
When tightening the syringe, only light tightening is needed to secure it, excessive force may damage the threaded structure.
2. Fault handling
Leakage issue: prioritize checking if the nut is tightened; If there is still leakage, the filter membrane needs to be reassembled or the seal needs to be replaced.
Squeezing difficulty: Check if the filter membrane is clogged or confirm that the blue protective membrane has not been mistakenly installed.
4、 Optimization suggestions
1. Sample size selection: The manual extruder is suitable for trace samples (0-1 mL), and it is recommended to test process parameters in small batches during the initial stage of the experiment.
2. Membrane pore size selection: Select a track etched membrane with an appropriate pore size based on the target particle size (e.g. a 100 nm membrane can obtain liposomes with a particle size of approximately 100 nm).
3. Record parameters: Record the number of extrusions, pressure changes, and final particle size distribution for process optimization.
Through the above steps, the preparation of liposomes with uniform particle size can be efficiently completed, while reducing operational risks.