The recipe
Three ingredients, in a specific ratio. DOPC, DOPG and cholesterol, combined at a 3:3:4 molar ratio, dissolved in a chloroform and ether mixture, spun down under reduced pressure until a thin lipid film forms on the container wall. Add a concentrated GHK-Cu solution, vortex until it suspends, then push the mixture through progressively finer mechanical steps: a tip-type ultrasonic homogeniser, then an extruder fitted with a polycarbonate membrane with pores only 100 nanometres wide.
That last step is not decorative. Forcing a lipid suspension through a membrane that fine is what turns a rough, uneven mixture of fat globules into a population of uniform, single-shelled spheres of a controlled size. It is the difference between a crude emulsion and an engineered particle.
Under a transmission electron microscope, that is exactly what shows up: spheres with a clear double membrane and a single internal vesicle, not a messy aggregate. The average diameter measured out to 117.2 nanometres, and the surface carried a zeta potential of -37.88 millivolts.
Why that second number matters more than it sounds like it should
Zeta potential measures the electrical charge sitting on a particle's surface, and it is the property that determines whether a suspension of particles stays evenly dispersed or clumps together and falls out of solution. A more negative or more positive value means the particles repel each other more strongly, which keeps them apart. Values close to zero mean particles have little to stop them from drifting together and aggregating.
At -37.88 millivolts, these liposomes sit solidly in the range considered stable for a colloidal suspension. That is a small, technical-sounding detail with a practical consequence: it tells you the batch of liposomes made for this experiment was not a one-off lucky preparation. It was a genuinely stable, reproducible particle, which is the baseline requirement before anything built from it can be taken seriously as a delivery platform rather than a lab curiosity.
The uptake experiment, and the wrinkle in it
Having built the shell, the obvious next question is whether it actually gets the cargo where it needs to go. The researchers measured copper content directly inside human umbilical vein endothelial cells, HUVECs, the standard laboratory stand-in for the cells that line blood vessels, using inductively coupled plasma spectrometry, a technique sensitive enough to quantify trace metal atoms inside a cell sample.
Copper uptake rose steadily across 3, 6, 12, 24 and 48 hours of exposure, and the liposomal form delivered more copper into the cells than free GHK-Cu did.
Here is the wrinkle, and it is worth sitting with rather than skipping past, because the paper is honest about it. By 24 hours, the total amount of copper that had made it inside the cell was not dramatically different between the liposomal and free forms. And yet, as later parts of this series cover, the liposomal form produced a clearly larger biological effect, more protein expression, more proliferation, than free GHK-Cu did at that same 24 hour mark.
That is a genuine, unresolved question sitting in the middle of this paper. If roughly similar amounts of copper are ending up inside the cell either way, then raw delivery volume is not the whole explanation for why the liposomal form performs better. The authors' own suggestion is that liposome-delivered cargo may end up in a different compartment inside the cell than cargo delivered freely, and that the lipid components of the shell itself might be doing some of the work, not merely acting as a passive courier.
That is a hypothesis, clearly labelled as one, not a settled finding. It is also the kind of loose thread that makes a preclinical paper worth reading in full rather than trusting the abstract alone. The headline claim, better performance, is real and measured. The explanation for why is still open.
What this sets up
A stable, well-characterised particle that delivers its cargo effectively, through a mechanism not yet fully pinned down, is the foundation everything else in this paper rests on. The real test is what that cargo does once it arrives, and specifically, whether it can do the one thing GHK-Cu has been credited with for fifty years: getting blood vessels to grow back into damaged tissue.
That is where the cell culture data gets genuinely interesting, and where the numbers start looking less like plumbing and more like biology.
This series covers a peer-reviewed preclinical study conducted in cell culture and in mice. It has not been tested in humans for wound healing, and nothing here is medical advice or a product claim.
