The Photonic Side of Curcumin: Microsphere Resonators Self‐Assembled from Curcumin Derivatives Emitting Visible/Near‐Infrared Light

Abstract

1 of 6) 1600613 emitting particles with curved or reflecting surfaces can act as photonic resonators if the surface acts as mirror and allow multiple total internal reflections (TIR) of light. Further, during TIR, due to light waves interference, the particle might generate optical whispering-gallery-mode (WGM) resonances [13] and the resultant resonance modes can be seen as a series of intensity amplified sharp lines (modes) in the FL spectrum. Although, organic particles self-assembled from dye molecules are known to display WGM effect, [14][15][16][17][18][19][20][21] to our knowledge no attempts have been made to investigate the photonic properties of a wellknown naturally occurring medicinal dye namely, curcumin, which is known for its PDT applications. Therefore, this paper unravels the hidden "photonic" side of microparticles composed of CURM derivatives (Figure 1). We present here large area self-assembly of CURM into nearly perfect µ-spheres with a narrow size distribution, which display enhanced WGMs in the visible electromagnetic region down to single particle level. Further to shift the resonance lines toward NIR region, CURM-BF was self-assembled into photonic particles. The polarization resolved microscopy revealed the polarized nature of the vis-NIR emissions from these medicinal particles. Additionally for the first time, confocal FL lifetime imaging microscopy (FLIM) studies on the CURM and CURM-BF resonators using a time correlated single photon counting (TCSPC) technique revealed a remarkable resonator size dependent FL lifetime values.Earlier in 1982, Tonnesen et al. have reported the first crystal structure (P2/n) of CURM. [22] Latter, many groups have reinvestigated its crystal structure. Recently, Nangia and co-workers have added two new crystalline polymorphs and an amorphous phase of CURM. [23] It has been found that CURM exists in β-keto-enol tautomeric form in all crystal structures. X-ray structure analysis revealed that various phenol OH···O (≈2.2 Å) and CH···O (≈2.5 Å) intermolecular hydrogen bond interactions play a key role in the solid state molecular packing of CURM. [22] In our experiment, to prepare spherical amorphous phase CURM particles suitable for photonic applications, both CURM and CURM-BF [7] were used (for chemical structure, see Figure 1). For the self-assembly studies, a methanol solution of CURM dye (1 mg mL −1 ) was subjected to ultrasonication for 30 s for complete dissolution and kept for 15 min without any disturbance at room temperature. Latter, two to three drops of the CURM solution was drop casted on a glass cover slip under slow evaporation condition to generate nano-/microparticles. Similar procedure was followed for CURM-BF self-assembly. To investigate the formation mechanism of spherical microparticles, solvent evaporation from the solution (three drops) at different temperatures

Strong Coupling in a Photonic Molecule Formed by Trapping a Microsphere in a Microtube Cavity

“…The hollow core of microtube cavity naturally provides a microfluidic channel facilitating "labinatube"based optofluidic sensing appli cations. In particular, the observation of mode anticrossing together with the mode intensity variation indicates efficient sensing capability in response to molecule adsorption/desorp tion from the cavity surfaces (e.g., probing the selfassembly dynamics of curcumin [53] ). Besides, the flexibility of regu lating the mode coupling and hybridization properties using this photonic molecule may imply promising applications for developing novel photonic devices such as light sources and optical filters.…”

Protein-based microsphere biolasers fabricated by dehydration

“…[1][2][3][4] Various biological materials including poly lactic-co-glycolicacid, starch, protein, pectin, cellulose, curcumin have been explored for laser microcavities. [5][6][7][8][9] Among these, bovine serum albumin (BSA) is considered to be an excellent biomaterial because of its biocompatibility and the ability to be transported in the human body. 10,11 Along with developments on new materials, new lasing architectures, as for example random lasing, 12,13 Fabry-Perot, 14,15 distributed feedback, 16,17 and whispering gallery mode (WGM) cavities [18][19][20][21] have been developed for biolasers.…”

“…Particularly, microspheres biolasers are very interesting owing to their simple fabrication, high quality (Q) factor, low lasing threshold and promising for ultra-sensitive biosensors with dimension down to the intracellular level. 22,23 Microsphere biolasers can be fabricated using several techniques such as freeze-drying vacuum, 7 slow solvent evaporation, 9 formation oil droplets in cells, 19 emulsion and dehydration of droplets in polydimethylsiloxane (PDMS). 8 Even though the available methods are effective for making microsphere biolasers, there are still several limitations including complicated multiple fabrication processes, 7,19 environmental unfriendly (using solvent) 8 and time-consuming (up to more than 12 hours) 7 .…”

Modal Analysis of β−Ga2O3:Cr Widely Tunable Luminescent Optical Microcavities

“…They can be fabricated with photonic crystals, Fabry-Perot, or distributed-Bragg-reflector (DBR) cavities [1], whispering gallery modes [2,3], or wave-guided modes [4]. Some of their functionalities are biosensors [3,5], optical filters, lasers [1], quantum memory [6], or energy harvesting [7].…”

“…They can be fabricated with photonic crystals, Fabry-Perot, or distributed-Bragg-reflector (DBR) cavities [1], whispering gallery modes [2,3], or wave-guided modes [4]. Some of their functionalities are biosensors [3,5], optical filters, lasers [1], quantum memory [6], or energy harvesting [7]. Since the first fabrication of a photonicband-gap microcavity within a silicon waveguide by x-ray lithography [8], the idea is extended to micro-and nanowires, creating the periodic pattern by techniques such as electron-beam lithography [9][10][11] or focused-ion-beam (FIB) milling [6,12,13].…”