Nanohybrid for Photodynamic Therapy and Fluorescence Imaging Tracking without Therapy

Abstract

Theranostic upconversion nanoparticles (UCNPs) are ideal candidates for personalized medicine. We present a smart, easy-to-prepare nanohybrid (NH) suitable for NIR-theragnosis and imaging tracking without triggering therapy simultaneously. The photophysical features of each component have been carefully selected in order to maximize the capabilities for theragnosis, in particular, the upconversion emission and the photosensitizer absorption. In addition, NH presents a fluorescent marker with one-photon absorption in the green and two-photon absorption cross-section at NIR wavelengths where the UCNP does not absorb, thus enabling innocuous tracking. Thus, the NH consists of NaYF4:Yb, Er, Tm (UCYbErTm) emitting in the UV, vis, and NIR; a broadband-absorbing natural porphyrin (PP) in the UV-to-NIR range but from 580 to 675 nm; and a 1,8-naphthalimide (NI) with two absorption bands (UV, VIS), and dual emission. In vitro assays demonstrate that UCYbErTm@PP/NI NH is noncytotoxic and extremely effective for NIR-induced cancer cell death. Moreover, this NH offers fluorescence tracking features without therapy due to the specific excitation of NI in the NIR and emission in the orange. This strategy opens up new alternatives for successful and noninvasive antitumoral theragnosis.

Exploring BODIPY Derivatives as Singlet Oxygen Photosensitizers for PDT

“…This is an interesting issue since photoactivation by white light allows topic daylight treatments of different skin disorders (acne, keratosis, skin tumors, etc.) produced by fungi, bacteria, etc (115‐121).…”

Wavelength‐Dependent Singlet Oxygen Generation in Luminescent Lanthanide Complexes with a Pyridine‐Bis(Carboxamide)‐Terthiophene Sensitizer

“…Upconverted Ln III ‐doped NPs decorated with Rose Bengal also display 1 O 2 generation . A NP doped with Yb III , Er III , and Tm III was decorated with a 1 O 2 ‐generating bacteriochlorin derivative and an orange‐emitting 1,8‐naphthalimide derivative; it could be selectively excited in the NIR for safer tracking . In addition, a NP with an Yb III /Tm III ‐doped core and a Nd III ‐containing shell was explored for its functionality as a 1 O 2 generator, and as an optical contrast agent and nanothermometer, using NIR luminescence …”

Lengthening the Lifetime of Common Emissive Probes to Microseconds by a Jigsaw‐Like Construction of NIR‐Responsive Nanohybrids

“…The emission tail is consistent with the relatively short dwell time used to record the images as compared to their luminescence lifetime. [ 22,26 ] The kinetic profiles obtained from these emission tails afforded lifetimes of 295 µs and 238 µs for UC Tm @CB@Y and UC Tm @CB@Y@F, respectively (Figure S11 and Table S2, Supporting Information). The shorter lifetime of UC Tm @CB@Y@F compared to that of UC Tm @CB@Y clearly proved the resonant energy transfer (RET) from the UC Tm to the F present on the nanohybrid, i.e., F is an acceptor and not just an absorption filter.…”

“…The chemical strategies usually employed to load a high concentration of a desired molecule of interest (e.g., biomolecules, probes, chromophores, or drugs) on an UCNP surface or its periphery are interdigitation of amphiphilic molecules, covalent linkage, ligand exchange or oxidation, and electrostatic interactions. [ 13,18,19 ] In the last few years, we have used strategies that are now well known to design smart photoactive upconversion nanohybrids for different purposes (e.g., colocalization of different payloads, [ 20 ] photodynamic therapy, [ 21,22 ] pH‐triggered release of a photosensitizer loaded on polymer coated‐UCNPs that are very resistant to strong acidic pHs, [ 23,24 ] etc.). Among them, cucurbituril‐capped UCNPs (UC@CB), easily prepared by reaction of bare UCNPs with CB, proved to be useful as a scaffold for cationic dyes, such as methylene blue, [ 25 ] thanks to the high electron density at the free CB carbonyl portal.…”