Construction of a Dual Drug Carrier on the Basis of Hollow Structured Upconversion Nanoparticles for pH‐Responsive Drug Delivery and UCL/MRI Dual Mode Imaging

Abstract

A series of Gd3+ doping hollow upconversion nanoparticles NaYF4:Yb,Gd,Tm (h‐UNCP) are prepared successfully. The hollow NaYF4:Yb,Gd,Tm possess excellent upconversion luminescence (UCL) and large longitudinal relativity (r1 = 128.3 mm−1 s−1), which can be potentially used for UCL/magnetic resonance imaging (MRI) dual mode imaging. On the basis of the optimal h‐UCNP, doxorubicin hydrochloride (DOX) and methotrexate (MTX) are used as drug models to prepare a dual drug carrier. After the encapsulation of DOX on the h‐UCNP, chitosan (CS) is further wrapped and then used to load MTX to obtain a dual drug carrier h‐UCNPs/DOX/CS/MTX. The pH responsive release of DOX and MTX is discussed. The MTX release climbs from 33% to 100% by regulating the pH from 5.8 to 7.4. The DOX release is different at different pH conditions. The synergistic effect of DOX and MTX on the cancer cells is confirmed by cell viability. The h‐UCNPs/DOX/CS/MTX are tracked by cells UCL imaging and vivo MRI imaging. The excellent performance of UCL imaging and positive MRI images demonstrates that h‐UCNPs/DOX/CS/MTX can be used for UCL/MRI dual mode imaging. All the results show the potential application of h‐UCNPs/DOX/CS/MTX in pH responsive release and UCL/MRI dual imaging.

Upconversion Nanoparticles for Cancer Therapy

“…As a result, doping representative Gd 3+ (single electrons at 4 f energy level, T1 relaxation) into the UCNP core and shell can allow them to be used as MRI contrast agents. NaYF 4 : Yb, Gd, Tm [ 92 ] and NaGdF 4 : Yb, Er, Tm@NaGdF 4 [ 93 ] UCNPs are such examples. Coating MnO 2 onto UCNPs also entails producing a bright MRI signal (T1), in which MnO 2 can be etched in a solution with a pH of 5.5–7.4, simulating the ones of the TME acid environment.…”

Quantification of the Activator and Sensitizer Ion Distributions in NaYF4:Yb3+, Er3+ Upconverting Nanoparticles Via Depth‐Profiling with Tender X‐Ray Photoemission

“…Spectrally shifting, upconverting nanoparticles (UCNPs), based on NaYF 4 that show photoluminescence (PL) in the ultraviolet (UV), visible, and near-infrared (NIR) regions, have drawn considerable attention due to their potential for applications in photocatalysis, [1] bioimaging and sensing, [2][3][4][5][6] non-invasive luminescence thermometry, [7,8] drug delivery, [9][10][11] extending the absorption range of solar energy devices, [12][13][14][15] and use in other optical devices. [16][17][18] During upconversion with Yb 3+ and Er 3+ doped NaYF 4 UCNPs, the sensitizer ions (Yb 3+ ) absorb NIR photons and transfer the energy of two or more photons to an activator ion (Er 3+ ).…”