Abstract
Core-shell (C/S) structured upconversion coated Fe3O4 nanoparticles (NPs) are of great interest due to their potential as magnetic resonance imaging (MRI) and upconversion luminescent (UCL) imaging agents, as well as near-infrared activated photodynamic therapy (PDT) platforms. When C/S structured Fe3O4@Mn2+-doped NaYF4:Yb/Er NPs were prepared previously, well-defined C/S-NPs could not be formed without the doping of Mn2+ during synthesis. Here, the role of Mn2+ doping on the synthesis of core-shell structured magnetic-upconversion nanoparticles (MUCNPs) is investigated in detail. Core-shell-shell nanoparticles (C/S/S-MUCNPs) with Fe3O4 as the core, an inert layer of Mn2+-doped NaYF4 and an outer shell consisting of Mn2+-doped NaYF4:Yb/Er were prepared. To further develop C/S/S-MUCNPs applications in the biological field, amphiphilic poly(maleic anhydride-alt-1-octadecene) (C18PMH) modified with amine functionalized methoxy poly(ethylene glycol) (C18PMH-mPEG) was used as a capping ligand to modify the surface of C/S/S-MUCNPs to improve biocompatibility. UCL imaging, T1-weighted MRI ascribed to the Mn2+ ions and T2-weighted MRI ascribed to the Fe3O4 core of C/S/S-MUCNPs were then evaluated. Finally, chlorine e6 (Ce6) was loaded on the C/S/S-MUCNPs and the PDT performance of these NPs was explored. Mn2+ doping is an effective method to control the formation of core-shell structured MUCNPs, which would be potential candidate as multifunctional nanoprobes for future T1/T2-weighted MR/UCL imaging and PDT platforms.
Highlights
In recent years, a combination of magnetic iron oxides with upconversion to obtain magnetic-upconversion nanoparticles (MUCNPs) has received intensive attention in various biomedical fields
MUCNPs possess both useful magnetic properties and upconversion luminescent (UCL) properties. This allows them to be applied as nanoprobes for in vitro and in vivo dual-modal magnetic resonance imaging (MRI)/UCL imaging, providing high sensitivity/resolution fluorescence imaging and non-invasive and high spatial resolution MRI for real-time monitoring [1]
After 24 h of incubation at a concentration of 500 μg·mL−1, the cells viability was approximately 81%. These results indicate that the prepared mPEG-C/S/S-MUCNPs exhibit low toxicity
Summary
A combination of magnetic iron oxides with upconversion to obtain magnetic-upconversion nanoparticles (MUCNPs) has received intensive attention in various biomedical fields. MUCNPs possess both useful magnetic properties and upconversion luminescent (UCL) properties. This allows them to be applied as nanoprobes for in vitro and in vivo dual-modal magnetic resonance imaging (MRI)/UCL imaging, providing high sensitivity/resolution fluorescence imaging and non-invasive and high spatial resolution MRI for real-time monitoring [1]. In addition to bioimNaangoimnagte,riMalsU20C18N, 8,PxsFhOaRvPeEEaRlsRoEVbIEeWen used for drug delivery and therapy in living cells and oaf n15imals. Therapy in living cells and Sanoimfaarl,s.sDevueeratol tdhiefifrerdeenept mpeentehtoradtisonh,aUvCe Lbeneanodpearvteiclloeps ecdontjuogpatreedpawriethMphUoCtoNsePnss,itiszuecrshhaasveusing mesobpeocoromuesimsipliocratanatsnaanionctaerrimeresdfoiartpeholatoydeyrntaomcicotmhebrianpey (UPCDTN)Pasgewntisth[2,3F]e.3O4 NPs [4,5,6], polymer encapsulaStoiofnar[,7s,e8v],erliagl adnifdfecrreonst smlinetkhiondgs [h9a,1v0e] baenedn ddierveecltopseeeddt-onupcrelepaatrieonM[U1C1–N1P3s],. Tuhcitss sweeitdh-gsrmowaltlhsizes, hstorumcotmchuogoermemetnhpsooe.ogdoOneunencnseatotnhsucteabrsnueosctntahrtupuuecpcrrlteelhuiaseartdeeansnadtonad,ndtcrtdoguanrntnoussatwnirbtuai[lboc1etln4es,M1mtso5tUeo]i.ctiCTcahNhlhiioiePoommssnesbeee,tytdrrs-yyuugcrsaaoihnnnwdgadtshcocManmanenney2tpyhi+aeoi,lreddatlrdaoMesfMfoUeafrCtUsseNenpCerPdNuoSsdPoewunSdcitttoawshswwicdtoihhtorhipecc-shoasmnrhaeates-llssllethso(ciCeozrln/eelSsdg),(uCl/atSe) the mstorrupcthuorelos.gOy nanthde flouthoerreshcaenndc,etrianntseintisointymoeftaUl CioNnsP, ss,uwchhaicshManls2+o, aprleayoftaenrouleseidn aTs1d-wopeaingthsetdo MRI contrraesgtualagteentthse. morphology and fluorescence intensity of UCNPs, which play a role in T1-weighed
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