Titanium, in particular Ti6Al4V, is a common material used in orthopaedic implants; it is biocompatible upon formation of the oxide layer on its surface, and has reasonably good mechanical properties.

A key metric of how orthopaedic implants are successful is their ‘osseointegration’. This is when the bone directly fuses and anchors to the implant, which ultimately reduces the rate of rejection and / or / failure. Ultimately, the first point of contact between bones and implant is, unsurprisingly, the bone surface and implant surface. Most commonly, the surface of the implant is modified, via sand blasting or chemical etching to increase the surface roughness and implant area to increase the chances of successful implant osseointegration. While the ‘holy grail’ of surface design is a fully antibacterial implant surface the secondary ‘nearly-as-holy-grail’ is to define the most optimal surface for osseointegration. With current conventional etching methods, the control required to achieve this surface is not possible is not achievable.

The natural question is then ‘what can give the control to obtain this secondary grail of controlled osseointegrable surface?’ If you’ve read any of my other blogs, you may make an educated guess and say ‘lasers’. If you read the title, you’d make a more precise guess of ‘femtosecond lasers’

Traditionally, implant surfaces are roughened through sandblasting or chemical etching, creating a texture that encourages bone growth. These methods, however, are stochastic: they yield surfaces that vary from one batch to another and can introduce contamination that requires extra cleaning steps. The result is a lack of control over the very features that dictate biological performance.

A recent paper by Lackington et al. (2022) explored exactly this. The team used a femtosecond laser to texture Ti6Al4V (also referred to as TiAlV) surfaces and compared their mechanical and biological performance to conventionally treated (sandblasted and acid-etched) samples. The researchers produced two kinds of laser patterns—one “random” and one “organized”—to see whether topographical order mattered to cell response.

Their findings were both reassuring and revealing. Structurally, the femtosecond-lasered surfaces had microscale pits about 15 µm wide, similar in roughness to those from sandblasting, but the precision was dramatically improved. The laser-textured surfaces were also superhydrophobic (contact angles around 150–160°) and exhibited a thicker oxide layer—about five times thicker than the conventionally treated surface. This oxide layer contributes to corrosion resistance and plays a role in early bone attachment.

Importantly, the femtosecond process preserved the underlying grain structure of the titanium alloy. In contrast, sandblasting produced heavy grain refinement near the surface, a known factor in fatigue reduction. Indeed, the laser-treated samples showed only a modest 15% drop in fatigue life—considerably less than the 40% drop sometimes reported for roughened implants—demonstrating that the process can produce functional roughness without critically weakening the bulk material.

On the biological side, both surfaces supported blood coagulation and human bone progenitor cell (HBC) attachment. The laser-textured samples showed similar levels of mineralization after 28 days compared with the conventionally roughened controls—an encouraging outcome considering the femtosecond process is cleaner, more reproducible, and entirely digital.

In short, the study shows that femtosecond laser texturing can create designer implant surfaces—tunable in geometry, reproducible in fabrication, and competitive in biological performance. While this doesn’t yet replace sandblasting and etching at industrial scale, it marks a shift from empirically roughening metal to engineering it at micron and nanoscales.

In the broader landscape of orthopaedic and dental implants, such control could eventually mean implants optimized not just for osseointegration, but for specific anatomical or patient needs—designed in CAD, written in light.

Reference:
W. A. Lackington et al., “Femtosecond Laser‐Texturing the Surface of Ti‐Based Implants to Improve Their Osseointegration Capacity,” Adv. Mater. Interfaces, 9, 2201164 (2022). DOI: 10.1002/admi.202201164