Using ‘labs’ on optical fiber probes to improve surface-enhanced Raman spectroscopy

Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for understanding the molecular composition of biological and chemical compounds. Since SERS is typically used in combination with a microscope, detection in situ is not possible.

But what if scientists could bring the experiment to the spectrometer rather than the other way around? Pisco et al. reviewed the most recent advances in lab-on-fiber technology and how it is changing the way scientists use SERS.

Fiber optic SERS probes, called “optrodes,” combine spectroscopy with the flexibility and versatility of fiber optic cables. These optrodes both serve as the light carrier (the fiber) and contain the molecules being analyzed (the lab).

“This allows the fiber not only to guide light but also to interact with the surrounding environment,” said author Marco Pisco. “SERS is widely used in lab research, and several fiber-based SERS probes have already been demonstrated.”

To create an optrode, researchers integrate nanostructures or nanomaterials into or around an optical fiber — or on the optical fiber tip — allowing minimally invasive in situ measurements via SERS. The researchers found a clear trend: Low-cost fabrication methods of SERS optrodes are becoming more popular, especially for biomedical applications, where disposable devices are needed. The authors’ case studies reveal that most of these optrodes, which are used for things like biomarker sensing, are disposable.

These optrodes have also been shown to be successful in detecting pathogens and DNA, sensing chemicals, and performing short-term and long-term diagnostics.

“What is still missing is the full integration of these platforms into real biomedical devices — such as needles or catheters for minimally invasive diagnostics — or into microfluidic systems for point-of-care applications,” Pisco said.

Source: “Lab-on-fiber technology: Towards engineered SERS optrodes,” by M. Pisco, G. Quero, M. A. Cutolo, M. Janneh, S. Spaziani, and A. Cusano, APL Photonics (2026). The article can be accessed at https://doi.org/10.1063/5.0307589 .