Bacteria Detection – 3D Printed Sensor On Fiber Optics

Raman spectroscopy is a powerful analytical technique that has been spotlighted for bacteria detection and diagnosis of diseases ranging from infection to cancer. However, as Raman signals are usually weak and can easily be swamped by interfering background signals, deploying Raman spectroscopy can be very challenging in the clinic.

One solution to enhance the signals generated from Raman spectroscopy is to metallize the surfaces with micro- and nanoscale structures. This significant signal enhancement effect is known as surface-enhanced Raman spectroscopy (SERS). Yet, developing miniature fiber-optic SERS probes can be problematic and requires advanced micro-fabrication technologies.

To tackle these issues, researchers developed a fiber optical sensor for label-free bacteria detection and characterization, along with a new protocol for simple, effective and reliable fabrication of miniature fiber-optic SERS probes. This novel miniaturized optical sensor can potentially be integrated into medical endoscopes for in-situ analysis of inflamed tissue.

The research team first 3D-printed polymer micro- and nano-structures on the tip of an optical fiber by using two-photon polymerization (2PP). This micro-scale 3D-printing technique is commercially available (Nanoscribe GmbH, Germany). These micro- and nano-structures are then coated with a thin layer of gold (50 nm) to produce the metal surfaces for Raman signal enhancement.

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