One‐Pot Template‐Free Synthesis of NaYF₄ Upconversion Hollow Nanospheres for Bioimaging and Drug Delivery

Abstract

Hollow-structured nanomaterials with fluorescent properties are extremely attractive for image-guided cancer therapy. In this paper, sub-100 nm and hydrophilic NaYF4 upconversion (UC) hollow nanospheres (HNSs) with multicolor UC luminescence and drug-delivery properties were successfully prepared by a facile one-pot template-free hydrothermal route using polyetherimide (PEI) polymer as the stabilizing agent. XRD, SEM, TEM, and N2-adsorption/desorption were used to characterize the as-obtained products. The growth mechanism of the HNSs has been systematically investigated on the basis of the Ostwald ripening. Under 980 nm excitation, UC emissions of HNSs can be tuned by a simple change of the concentration or combination of various upconverters. As a result, the PEI-coated HNSs could be used as efficient probes for in vitro upconversion luminescence (UCL) cell imaging. Furthermore, a doxorubicin storage/release behavior and cancer-cell-killing ability investigation reveal that the product has the potential to be a drug carrier for cancer therapy.

Phytotoxicity, Translocation, and Biotransformation of NaYF4Upconversion Nanoparticles in a Soybean Plant

“…PEI, a commonly used surface modification agent, was chosen to modify the surface of UCNPs. Hence, the PEI‐modified NaYF 4 :Yb,Er UCNPs (PEI‐UCNPs) were synthesized by a modified one‐step solvothermal method . The SEM ( Figure a) and transmission electron microscopes (TEM) images (inset in Figure a) clearly reveal that the UCNPs are spherical.…”

“…Additionally, NPs may undergo transformations in a plant system, which will modify their ultimate toxicity and behavior in plants. For example, Zhang et al reported that RE oxide NPs (La 2 O 3 , Yb 2 O 3 , and CeO 2 ) were transformed into RE phosphates with the assistance of root‐exuded organic acids and reducing substances, which affected the phytotoxicity and behavior of NPs . NaYF 4 , as one of the most effective upconversion luminescent nanomaterials, there are few reports about the toxicity effect of NaYF 4 UCNPs on plants .…”

Upconversion nanoparticle as a theranostic agent for tumor imaging and therapy

“…50 As an example, Li reported an e±cient, one-pot route for synthesizing sub-100 nm hydrophilic NaYF 4 -based upconversion hollow nanospheres in hydrothermal condition. 51 …”

A facile strategy for the synthesis of a NaREF4-gold nanocomposite as a dual-modal bioimaging agent

“…Non-invasive imaging has become a useful tool for bioimaging, detection and medical diagnosis. [1][2][3][4][5][6][7][8] To date, lots of non-invasive imaging techniques, including uorescence imaging, 9 magnetic resonance imaging (MRI), 10 X-ray computed tomography (CT), 11 positron emission tomography (PET), 4,11,12 single-photon emission computed tomography (SPECT) 12 and photoacoustic tomography (PAT), 13,14 have been developed. As every single technique has its own limits (e.g., spatial resolution, imaging depth and scanning speed), developing multimodal noninvasive imaging is of great importance to combine the merits of individual imaging techniques.…”