Does laser marking affect the biocompatibility of the screws?

Laser marking technology is widely used in the medical field for marking bone screws, but users are concerned about possible adverse effects on the material.By comparing data on the strength, corrosion resistance, and biocompatibility of the screws before and after laser marking, the team was able to answer questions about the safety of the technology, providing scientific guidance to medical professionals and patients alike.

Why are people so concerned about the effect of laser marking on the bone screws?

The safety of the materials is a top concern for medical screws, which are implanted into the human body.Although laser marking can accurately print marks, many people wonder whether the high temperatures involved in the process might change the structure of the metal. Could the marked area be more prone to rust? Could the laser marking process even affect the healing of the bone?

Key indicators before and after the labeling.

We selected two types of commonly used bone screws made of titanium alloy and stainless steel, and performed laser marking on them, then tested them in the lab to verify three core performance characteristics.

The tensile strength has changed.

Compared with samples that had not been marked, the tensile strength of the laser-processed pins dropped by only 0.3-1.2 %.This figure is within the range of error for medical materials, which shows that, if the laser energy is controlled properly, there will be no significant weakening of the nail's "compression strength.

Corrosion resistance testing.

After soaking the bone nails in simulated body fluid for 30 days, it was observed under a microscope that the corrosion rate of the marked areas was less than 5 % different from that of the unmarked areas.In other words, as long as the post-processing passivation treatment is done properly, laser marking does not make the pins "more prone to rust.

Biocompatibility test.

Cell-culture experiments show that the rate of cell attachment in the laser-etched area is basically the same as that in the nonetched area.There are even data to show that a certain degree of roughness can stimulate the growth of osteoblasts. Of course, this discovery still needs more clinical support.

What do you need to be aware of in practical applications?

Although the data show that laser marking meets safety standards, there are still several details to be aware of when using the technique.

Choose a femtosecond laser with a shorter pulse width to reduce the heat-affected zone.

After laser marking, the metal must be polished with electrolysis or chemically treated.

Avoid marking the critical load-bearing areas of the screw thread or implant.

Doctors and manufacturers.

We interviewed Dr. Wang, chief of the orthopedic department at a top-level hospital in Taiwan. "From clinical feedback, there have been no cases of abnormal rejection of laser-marked screws in the last five years.A technical director at a medical device manufacturer also says: "Nowadays, the industry generally uses low-power multiple-scan technology, which is like carving with a needle instead of a hammer.The only thing they can do is to make a lot of money.

(Chang Ch'ao-t'ang / photos by Arthur Cheng / tr. by Christopher Hughes)

In summary, the laser marking of orthopedic implants does not affect their biocompatibility.But selecting reliable suppliers and ensuring that the processing process is in compliance with regulations remains the key to ensuring safety.The next time you see a small inscription on a bone pin, you can feel a little more reassured.