Unveiling NIR Aza‐Boron‐Dipyrromethene (BODIPY) Dyes as Raman Probes: Surface‐Enhanced Raman Scattering (SERS)‐Guided Selective Detection and Imaging of Human Cancer Cells

Abstract

The development of new Raman reporters has attracted immense attention in diagnostic research based on surface enhanced Raman scattering (SERS) techniques, which is a well established method for ultrasensitive detection through molecular fingerprinting and imaging. Herein, for the first time, we report the unique and efficient Raman active features of the selected aza-BODIPY dyes 1-6. These distinctive attributes could be extended at the molecular level to allow detection through SERS upon adsorption onto nano-roughened gold surface. Among the newly revealed Raman reporters, the amino substituted derivative 4 showed high signal intensity at very low concentrations (ca. 0.4 μm for 4-Au). Interestingly, an efficient nanoprobe has been constructed by using gold nanoparticles as SERS substrate, and 4 as the Raman reporter (4-Au@PEG), which unexpectedly showed efficient recognition of three human cancer cells (lung: A549, cervical: HeLa, Fibrosarcoma: HT-1080) without any specific surface marker. We observed well reflected and resolved Raman mapping and characteristic signature peaks whereas, such recognition was not observed in normal fibroblast (3T3L1) cells. To confirm these findings, a SERS nanoprobe was conjugated with a specific tumour targeting marker, EGFR (Epidermal Growth Factor Receptor), a well known targeted agent for Human Fibrosarcoma (HT1080). This nanoprobe efficiently targeted the surface marker of HT1080 cells, threreby demonstrating its use as an ultrasensitive Raman probe for detection and targeted imaging, leaving normal cells unaffected.

Two-Dimensional Electronic Spectroscopy Reveals Dynamics and Mechanisms of Solvent-Driven Inertial Relaxation in Polar BODIPY Dyes

“…Spectra have been normalized on the 1606 cm –1 band assigned to the C=C–N stretching. 18 Computed stick Raman spectra computed at the harmonic level are also reported for comparison. The frequencies are scaled by a factor of 0.98 to account empirically for anharmonic effects.…”

Advances in surface‐enhanced Raman spectroscopy for cancer diagnosis and staging

“…Phenotypical discrimination among normal and cancer breast cells was demonstrated through labelled SERS mapping using hollow Au sphere core @ Raman reporter @ silica shell nanoparticles conjugated with EGFR, ErbB2, and IGF‐1R antibodies, wherein the Raman reporter molecules were malachite green isothiocyanate and Rhodamine B isothiocyanate (RBITC), respectively. Recent studies have focused on Raman reporters, such as tetraphenylethylene (TPE), cyanine derivatives, and azo‐BODIPY, for achieving efficient Raman enhancement. (E)‐2‐((4‐(phenylethynyl)benzylidene)amino)ethanethiol PBAT is tested as a Raman reporter molecule, which shows Raman peak at cellular silent region (18,00–2,800 cm −1 ) .…”

Ultrasonic‐Assisted Synthesis of Highly Defined Silver Nanodimers by Self‐Assembly for Improved Surface‐Enhanced Raman Spectroscopy

“…Surface-enhancedR amans pectroscopy (SERS)h as received considerable attention as ap owerful toolf or bioanalysis. [1] This technique enhancesRamansignals from 4to1 1orders of magnitude by electromagnetic and chemical enhancementb y using metal nanostructures. [2] In comparison to organic fluorophores,w hicha re standardi ns ensing and microscope imaging, [3] SERS shows several advantages:1 )ultrahigh sensitivity, even for single-molecules, [4] 2) 10-100 times narrower bandwidth of peaks, [5] 3) resistance to photobleaching, saturation, and degradation,4 )capability to be driven by near-infrared light.…”