Discriminative spatial localisation in confocal reflectance and carbon dots-based fluorescence imaging using mixed-mode endoscopic scanner

• DOI: 10.1080/15599612.2024.2347292
• Publication Date: 2024-05-09T16:06:10Z
• Authors: Yang Sing Leong; Mohd Hadri Hafiz ...; Nur Afifah Ahmad ...; Mohd Hafiz Abu Bakar; Mohd Saiful Dzulk...; Norhana Arsad; Peer Mohamed Abdul; Ahmad Ashrif A. B...
• Keywords: confocal reflectance; fluorescence imaging; Lissajous scanning; carbon dots; TA401-492; Applied optics. Photonics; Materials of engineering and construction. Mechanics of materials; 01 natural sciences; endoscopic scanner; TA1501-1820; 0104 chemical sciences

Carbon dots (CDs)-based fluorescence imaging with confocal reflectance effectively localises labelled structures with clear sample visualization. Yet, integrating these modalities into single-fibre cantilever-based endoscopic scanners poses challenges. Thus, we present an endoscopic scanner with a mixed-mode fibre cantilever for dual modalities imaging. The cantilever features two-attached fibre construction for multiple illumination and detection channels without additional optical components. The measured lateral and axial resolutions are 5.81 and 6.52 µm, respectively with field-of-view of 408 × 488 µm. The fluorescence detection capability was first verified using fluorescent microspheres and CD-embedded polymer film, followed by confocal reflectance and CDs-based fluorescence imaging on labelled fibrous network and plant samples. The results demonstrate the complementary strengths of confocal reflectance, which extracts surface profiles, and CDs-based fluorescence, which captures fluorescence signals, leading to precise localization of fluorescence signals within the sample. Switching modality schemes at the scanner’s back-end enables implementation of different modalities.