We developed a miniaturized high-resolution low-cost reflectance-mode fiber microscope (RFM) aimed at optical tissue biopsy applications using a polarized imaging configuration to suppress background noise from specular reflectance. The RFM is equipped with an air-cooled light-emitting-diode illumination module and a single 450-µm outer-diameter fiber bundle image guide compatible with a 20-gauge needle. The dual illumination and image acquisition nature of the fiber bundle simplifies the system and reduces the total cost. Imaging tests with a United States Air Force resolution target demonstrate a lateral resolution of ~3.5 µm. The performance of the imaging system is evaluated by examining samples of cells and excised human tissue. Still and video rate images are obtainable in reflectance mode using intrinsic contrast.
We demonstrate a novel quantum dot based probe with inherent signal amplification upon interaction with a targeted proteolytic enzyme. This probe may be useful for imaging in cancer detection and diagnosis. In this system, quantum dots (QDs) are bound to gold nanoparticles (AuNPs) via a proteolytically-degradable peptide sequence to non-radiatively suppress luminescence. A 71% reduction in luminescence was achieved with conjugation of AuNPs to QDs. Peptide cleavage results in release of AuNPs and restores radiative QD photoluminescence. Initial studies observed a 52% rise in luminescence over 47 hours of exposure to 0.2 mg/mL collagenase. These probes can be customized for targeted degradation simply by changing the sequence of the peptide linker.