Lanthanide-doped mesoporous MCM-41 nanoparticles as a novel optical–magnetic multifunctional nanobioprobe

To research and develop potential multifunctional nanoprobes for biological application, lanthanide-doped MCM-41 (Ln-MCM-41, Ln = Gd/Eu) silica nanoparticles with excellent pore structure and optical–magnetic properties were synthesized via a facile and economical sol–gel method. The microstructure and pore distribution of Ln-MCM-41 nanoparticles were obviously affected by the Ln-doping. As the Ln/Si mole ratio increased, the specific surface area and total pore volume of Ln-MCM-41 nanoparticles rapidly decreased. However, the Ln-MCM-41 nanoparticles still retained the typical well-ordered mesoporous structure, and exhibited excellent drug release behavior. Moreover, the drug release rate of Ln-MCM-41 was remarkably pH-dependent and increased gradually upon decreasing pH. Additionally, these nanoparticles also exhibit considerable photoluminescence properties, living cells photoluminescence imaging in vitro, and paramagnetism behavior at room temperature due to the Ln³⁺-ions doping. Our research shows the possibility of our Ln-MCM-41 nanoparticles as multifunctional nanoprobes for application in bioseparation, bioimaging, and drug delivery.

Mesoporous Ln-MCM-41 nanoparticles with optical–magnetic dual-modal properties can be used as a multifunctional nanoprobe for application in bioseparation, optical–magnetic bioimaging, and drug delivery.     

Magnetoliposomes with size controllable insertion of magnetic nanoparticles for efficient targeting of cancer cells

Liposomes with embedded magnetic nanoparticles (magnetoliposomes; MLs) are promising nano-platforms for various biomedical applications. The magnetic behavior of MLs depends on the size of embedded magnetic nanoparticles (MNPs); in general, larger MNPs are more advantageous (e.g. increased magnetic signals). However, the insertion of large MNPs into liposome bilayers is constrained by the thickness of the membrane (∼3.4 nm); thus, the incorporation of larger magnetic nanoparticles (>3.4 nm) into liposomes is a major challenge. We developed a solvent-guided approach for the simple and efficient insertion of large MNPs (6 nm or 15 nm) into the liposomal bilayer. MLs with 6 nm MNPs were used for the magnetic field-guided separation of cancer cells by targeting to human epidermal receptor 2 and folate receptor. We also evaluated the nuclear delivery of oligonucleotides by MLs with a cationic lipid formula. The MLs are expected to be versatile nano-platforms for biomedical applications (e.g. disease diagnosis, therapeutics and cell tracking).

Cationic magnetoliposomes enable to achieve efficient capture of cells and intracellular delivery of oligonucleotides into nucleus through cancer cell-specific targeting.     

Highly stable mesoporous silica nanospheres embedded with FeCo/graphitic shell nanocrystals as magnetically recyclable multifunctional adsorbents for wastewater treatment

Highly stable and magnetically separable mesoporous silica nanospheres (MSNs) embedded with 4.6 ± 0.8 nm FeCo/graphitic carbon shell nanocrystals (FeCo/GC NCs@MSNs) were synthesized by thermal decomposition of metal precursors in MSNs and subsequent methane CVD. The FeCo/GC NCs@MSNs had a high specific surface area (442 m² g⁻¹), large pore volume (0.65 cm³ g⁻¹), and tunable size (65 nm, 130 nm, and 270 nm). Despite the low magnetic metal content (8.35 wt%), the FeCo/GC NCs@MSNs had a sufficiently high saturation magnetization (17.1 emu g⁻¹). This is due to the superior magnetic properties of the FeCo/GC NCs, which also enable fast magnetic separation of the nanospheres. The graphitic carbon shell on the FeCo NCs not only protects the alloy core against oxidation and acid etching in 35% HCl_(aq), but also facilitates non-covalent, hydrophobic interactions with the hydrocarbon chains of organic dyes such as methyl orange and methylene blue. Surface functionalization of the FeCo/GC NCs@MSNs with thiol groups provides efficient capacity for binding with Hg²⁺ ions. We have shown that the thiol-functionalized FeCo/GC NCs@MSNs (FeCo/GC NCs@MSNs-SH) work as multifunctional adsorbents for organic dyes (target organic pollutants) and Hg²⁺ ions (target inorganic pollutant). We also demonstrated that the FeCo/GC NCs@MSNs-SH are excellent recyclable adsorbents for methyl orange.

We report the first synthesis of highly stable and efficiently recyclable multifunctional adsorbents containing FeCo/GC nanoparticles with the strongest magnetic properties.     

Magnetically targeted nanoparticles for imaging-guided photothermal therapy of cancer

Over the past several decades, nanocarriers have constituted a vital research area for accurate tumor therapy. Herein, magnetically targeted nanoparticles (IRFes) for photothermal therapy were generated by integrating IR780, a molecule with strong emission and absorption in the NIR spectrum and the ability to produce heat after laser irradiation, with Fe₃O₄ nanoparticles (NPs). These IRFes were guided to the tumor site by the application of an external magnetic field. In particular, the strong NIR absorption of IR780 was used for NIRF imaging, and we also demonstrated effective magnetic targeting for the photothermal ablation of tumors. In vitro cell viability and in vivo antitumor experiments showed that these IRFes can ablate 4T1 cells or transplanted 4T1 cell tumors when exposed to 808 nm laser irradiation and a magnetic field. In vivo experiments showed that IRFes only act on tumors, do not damage other organs and can be used to image tumors. These results demonstrate the enormous potential of local photothermal therapy for cancer under the guidance of external magnetic fields and reveal the prospect for the use of multifunctional nanoparticles in tumor therapy.

Magnetically targeted nanoparticles (IRFes) for photothermal therapy were generated by integrating IR780, a molecule with strong emission and absorption in the NIR spectrum and the ability to produce heat after laser irradiation, with Fe₃O₄ nanoparticles.     

Effective in vitro delivery of paclitaxel by nanocargo of mesoporous polycaprolactone against triple negative breast cancer cells by minimalizing drug dose

Among the breast cancers, triple negative breast cancer (TNBC) has relatively poor outcomes with a lower survival rate and personalised chemotherapy is the only option available for treatment. Currently in the biomedical domain, nanomaterials with porous morphology have revealed their tremendous possibilities to be used as a nanocarrier in treating cancer by offering void space to encapsulate/entrap biological agents. However, the development of nanocarrier-based targeted therapy with high therapeutic efficacy and fewer side effects to normal cells is always a challenge. Here, we have developed nanocargos based on biodegradable mesoporous PCL (polycaprolactone) of approx. diameter of 75 nm by template removal synthesis techniques. Succeeding the comparative analysis of the nanocarriers, the efficiencies of core shell PCL-mZnO (PZ) and mesoporous PCL (HPZ) to deliver paclitaxel (Taxol/T) into breast cancer cells, is investigated. We found that HPZ nanocapsules have less cytotoxicity and drug loading efficiency of about 600 μg mg⁻¹. The Taxol-loaded nanoparticles (T-HPZ) have exhibited more cytotoxicity than Taxol alone treated cancer cells. Furthermore, T-HPZ treated MDA-MB231 cells are accumulated at G2/M phase of the cell cycle and eventually undergo apoptosis. In support of this, anchorage independent growth of MDA-MB231 cells are significantly inhibited by T-HPZ treatment. Together, our findings suggest that T-HPZ-based paclitaxel (Taxol/T) loaded nanoparticles provide a novel therapeutic option in the treatment of TNBC.

Porous-PCL-nanocapsules-Taxol is an effective nanomedicine for the treatment of triple negative breast cancer which can reduce the extent of side effects also.     

Amphiphilic copolymer self-assembly of magnetic nanoparticles for construction of magnetically responsive photonic crystals based on steric hindrance

Herein, a facile, simple and rapid self-assembly of magnetic colloidal nanoparticles (MCNPs) to build magnetically responsive photonic crystals (MRPCs) was devolved. A nonionic amphiphilic random copolymer poly(styrene-co-vinylpyrrolidone) P(St-co-VP) with the monomer molar ratio of 1 : 9 was used not only as an emulsifier for miniemulsion self-assembly of Fe₃O₄ magnetic nanoclusters, but also as the coating material on the magnetic nanoclusters through itself assembly. The self-assembly of the magnetic nanocluster and the polymer coating were completed simultaneously without another polymerization process. The characterization of the MCNPs and the optical properties of the MRPCs were investigated in details. TEM showed that the MCNPs had regular spherical structures with an average diameter of 104.6 nm (RSD = 13.9%, n = 100). P(St-co-VP) self-assembly coating was confirmed by IR and XPS, and thermogravimetric analysis showed that the magnetite content was 76.15%. The large content of magnetite and the thin coating of the copolymer gave MCNPs the high saturated magnetization (M_s) of 52.60 emu g⁻¹. Under an external magnetic field, the MCNPs could assemble MRPCs instantaneously and reversibly. The structural color covered entire visible spectrum by tuning the strength of the external magnetic field. On basis of the steric hindrance from neighboring PVP stretching chains, rather than electrostatic repulsion or solvation layer to counterbalance magnetic attraction, the MRPCs could tolerate the electrolyte as high as 0.10 mol L⁻¹ and the variance of pH from 2.0–12.0. The stability of P(St-co-VP) self-assembly coating was testified through the invariability of the structural color of MRPCs after repeated washing, as well as the recovery of structural color after removing the electrolytes.

One-step self-assembly of magnetic nanoparticles with amphiphilic copolymer for construction of magnetically responsive photonic crystals based on steric hindrance.     

Modified core–shell magnetic mesoporous zirconia nanoparticles formed through a facile “outside-to-inside” way for CT/MRI dual-modal imaging and magnetic targeting cancer chemotherapy

Iron oxide based magnetic nanoparticles (MNPs) as typical theranostic nanoagents have been popularly used in various biomedical applications. Conventional core–shell MNPs are usually synthesized from inside to outside. This method has strict requirements on the interface properties of magnetic cores and the precursors of the coating shell. The shape and size of MNPs are significantly influenced by that of the pre-synthesized magnetic cores. Most core–shell MNPs have only single T2W MRI imaging ability. Herein, we propose a new synthetic strategy for core-mesoporous shell structural MNPs, where hollow mesoporous nanospheres which exhibit an intrinsic property for both CT imaging and drug loading were used as the shell and the magnetic cores were produced in the cavity of the shell. A new type of MNPs, Fe₃O₄@ZrO₂ nanoparticles (M-MZNs), were developed using this facile outside-to-inside way, where multiple Fe₃O₄ nanoparticles grew inside the cavity of the mesoporous hollow ZrO₂ nanospheres through chemical coprecipitation. The obtained MNPs not only exhibited superior magnetic properties and CT/MR imaging ability but also high drug loading capacity. In vitro experiment results revealed that M-MZNs-PEG loaded with doxorubicin (DOX) presented selective growth inhibition against cancer cells due to pH-sensitive DOX release and enhanced endocytosis by cancer cells under a magnetic field. Furthermore, the proposed MNPs exhibited CT/MRI dual modal imaging ability and effective physical targeting to tumor sites in vivo. More importantly, experiments of magnetic targeting chemotherapy on tumor bearing mice demonstrated that the nanocomposites significantly suppressed tumor growth without obvious pathological damage to major organs. Henceforth, this study provides a new strategy for CT/MRI dual-modal imaging guided and magnetic targeting cancer therapy.

Magnetic mesoporous zirconia nanoparticle was synthesized by producing multiple iron oxide cores inside the cavity of mesoporous ZrO₂ hollow nanospheres and was used for CT/MRI dual-modal imaging and magnetic targeting chemotherapy.     

Magnetically targeted co-delivery of hydrophilic and hydrophobic drugs with hollow mesoporous ferrite nanoparticles

A magnetically targeted drug delivery system (DDS) is developed to solve the delivery problem of hydrophobic drugs by using hollow mesoporous ferrite nanoparticles (HMFNs). The HMFNs are synthesized by a one-pot hydrothermal method based on the Ostwald ripening process. The biocompatibility of the synthesized HMFNs was determined by MTT assay, lactate dehydrogenase (LDH) leakage assay and hemolyticity against rabbit red blood cells. Moreover, Prussian blue staining and bio-TEM observations showed that the cell uptake of nanocarriers was in a dose and time-dependent manner, and the nanoparticles accumulate mostly in the cytoplasm. A typical highly hydrophobic anti-tuberculosis drug, rifampin (RFP) was loaded into HMFNs using supercritical carbon dioxide (SC-CO₂) impregnation, and the drug loading amount reached as high as 18.25 wt%. In addition, HMFNs could co-encapsulate and co-deliver hydrophobic (RFP) and hydrophilic (isoniazide, INH) drugs simultaneously. The in vitro release tests demonstrated extra sustained co-release profiles of rifampicin and isoniazide from HMFNs. Based on this novel design strategy, the co-delivery of drugs in the same carrier enables a drug delivery system with efficient enhanced chemotherapeutic effect.

A magnetically targeted drug delivery system (DDS) is developed to solve the delivery problem of hydrophobic drugs by using hollow mesoporous ferrite nanoparticles (HMFNs).     

Porous MnFe2O4-decorated PB nanocomposites: a new theranostic agent for boosted T1/T2 MRI-guided synergistic photothermal/magnetic hyperthermia

This study reports a multifunctional core/shell nanoparticle (NP) that can be used for amplified magnetic resonance image (MRI), enhanced photothermal therapy (PTT) and magnetic hyperthermia therapy (MHT) due to its surface coating with a porous shell. Importantly, by means of introducing the surface coating of a porous shell, it helps entrap large quantities of water around NPs and allow more efficient water exchange, leading to greatly improved MR contrast signals. Besides, the porous shell helps the near-infrared (NIR) absorbance of the core, and then the extremely enhanced thermal effect can be obtained under synergistic combination of PTT and MHT. By synthesizing multifunctional porous MnFe₂O₄/PB as an example, we found that the transversal relaxivity (r₂) of MnFe₂O₄ NPs might improve from 112.11 to 123.46 mM⁻¹ s⁻¹, and the specific absorption rate (SAR) of MnFe₂O₄/PB nanoparticles reached unprecedented levels of up to 4800 W g⁻¹ compared with the SAR 1182 W g⁻¹ of PTT under an 808 nm laser and 180 W g⁻¹ of MHT under an external AC magnetic field. Meanwhile, when MnFe₂O₄ was decorated on PB nanoparticles, the magnetic properties became lower slightly, but the synergistic photothermal/magnetic hyperthermia conversion was enhanced greatly. Subsequently, in vitro T₁–T₂ dual-modal MRI, PTT and MHT results verified that MnFe₂O₄/PB could serve as an excellent MRI/PTT/MHT theranostic agent. Furthermore, the MnFe₂O₄/PB NPs were applied as a T₁–T₂ dual-modal MRI, PTT and MHT theranostic agent for in vivo MRI-guided photothermal and magnetic hyperthermia ablation of tumors by intratumoral injection in 4T1 tumor-bearing mice. The T₁–T₂ dual-modal MR imaging result shows a significantly contrast in the tumor site. The MPB-mediated PTT and MHT result shows high therapeutic efficiency as a result of high photothermal and magnetic hyperthermia conversion efficiency. The multifunctional NPs have a great potential application for future clinical tumorous diagnosis and treatment.

We synthesized a new theranostic agent of porous MnFe₂O₄-decorated PB nanocomposites for boosted T₁/T₂ MRI-guided synergistic photothermal/magnetic hyperthermia.     

Synthesis and characterization of magnetic chitosan microspheres for drug delivery

A novel magnetic microsphere was prepared by simple microemulsion polymerization for protein drug delivery systems. The Fe₃O₄ magnetic nanoparticles were successfully encapsulated in chitosan microspheres, which endowed the chitosan microspheres with good magnetism. The drug loading performance results indicated that the prepared magnetic chitosan microspheres exhibited a superior drug loading capacity, and the drug loading amount reached 947.01 mg g⁻¹. Furthermore, the magnetic chitosan microspheres also showed a higher drug release rate (87.8%) and evident sustained-release performance in vitro. The magnetic microsphere carrier will be widely used in the biomedical field as a promising drug carrier.

A novel magnetic microsphere was prepared by the simple microemulsion polymerization for protein drug delivery systems. This magnetic microsphere exhibited good magnetism and superior drug loading capacity and evident sustained-release performance.     

Folic acid-conjugated magnetic mesoporous silica nanoparticles loaded with quercetin: a theranostic approach for cancer management

The development of drug carriers based on nanomaterials that can selectively carry chemotherapeutic agents to cancer cells has become a major focus in biomedical research. A novel pH-sensitive multifunctional envelope-type mesoporous silica nanoparticle (SBA-15) was fabricated for targeted drug delivery to human colorectal carcinoma cells (HCT-116). SBA-15 was functionalized with folic acid (FA), and the material was loaded with the water-insoluble flavonoid, quercetin (QN). Additionally, acid-labile magnetite Fe₃O₄ nanoparticles were embedded over the FA-functionalized QN-loaded monodisperse SBA-15 to prepare the highly orchestrated material FA-FE-SBA15QN. The in vitro and in vivo anti-carcinogenic efficacy of FA-FE-SBA15QN was carried out to explore the pH-sensitive QN release with putative mechanistic aspects. FA-FE-SBA15QN caused a marked tumor suppression, and triggered mitochondrial-dependent apoptosis through a redox-regulated cellular signaling system. Furthermore, FA-IO-SBA-15-QN initiated the c-Jun N-terminal Kinase (JNK)-guided H2AX phosphorylation, which relayed the downstream apoptotic signal to the phosphorylate tumor suppressor protein, p53. On the other hand, the selective inhibition of heat shock protein-27 (HSP-27) by FA-FE-SBA15QN augmented the apoptotic fate through JNK/H2AX/p53 axis. The in vitro and in vivo magnetic resonance imaging (MRI) studies have indicated the theranostic perspective of the composite. Thus, the result suggested that the newly synthesized FA-FE-SBA15QN could be used as a promising chemo theranostic material for the management of carcinoma.

pH-Sensitive quercetin/Fe₃O₄ NPs loaded functionalized mesoporous SBA-15 fabricated for targeted drug delivery to colorectal carcinoma cells with high anti-carcinogenic efficacy.     

Chitosan magnetic nanoparticles for pH responsive Bortezomib release in cancer therapy

The use of nanotechnology in cancer treatment offers exciting opportunities, including the possibility of destroying tumors with minimal damage to healthy tissue by novel targeted drug delivery systems. pH differences between healthy and tumor microenvironment provide pH responsive release of drugs at tumor site via smart nanoparticles. In this study, chitosan coated superparamagnetic iron oxide nanoparticles (CS MNPs) were in situ synthesized by ionic crosslinking method as nanocarrier systems and loaded with the drug Bortezomib (Velcade^®). The drug loading capacity, drug release and stability of CS MNPs were analyzed. CS MNPs were visualized inside the cells by fluorescence microscopy. The cytotoxicity of Bortezomib, CS MNPs and Bortezomib loaded CS MNPs were tested by XTT analyses in vitro. Gene expression analyses revealed that pro-apoptotic PUMA and NOXA genes were upregulated while anti-apoptotic BCL-2, SURVIVIN and cIAP-2 genes were downregulated at Bortezomib loaded CS MNP treated cells. Immunocytochemical analyses demonstrated an increase in p53 tumor suppressor protein levels at treated cells, which supports the upregulation of PUMA and NOXA genes, while Survivin protein level did not significantly change. This study points out that the pH responsive magnetic targeting of Bortezomib is more efficacious than free drug treatment. Moreover, targeted delivery of Bortezomib would reduce the frequency of drug administration by lowering the required amount of drug dose.     

Synthesis of crosslinkable diblock terpolymers PDPA-b-P(NMS-co-OEG) and preparation of shell-crosslinked pH/redox-dual responsive micelles as smart nanomaterials

Crosslinked polymer nanomaterials have attracted great attention due to their stability and highly controllable drug delivery; herein, a series of well-defined amphiphilic PDPA-b-P(NMS-co-OEG) diblock terpolymers (P1–P3) were designed and prepared via RAFT polymerization and were self-assembled into non-cross-linked (NCL) nanomicelles, which were further prepared into shell-cross-linked (SCL) micelles via cystamine-based in situ shell cross-linking. Using P3 as an optimized polymer, SCL-P3 micelles were prepared, which demonstrated remarkable pH/redox-dual responsive behaviour. For drug delivery, camptothecin (CPT)-loaded SCL-P3 micelles were prepared and showed much higher CPT-loading capability than their NCL-P3 counterparts. Notably, the SCL-P3 micelles showed good synergistic pH/redox-dual responsive CPT release properties, making them potential “smart” nanocarriers for drug delivery.

A series of well-defined amphiphilic PDPA-b-P(NMS-co-OEG) diblock terpolymers were prepared via RAFT polymerization and self-assembled into non-cross-linked nanomicelles, and then shell-cross-linked micelles via cystamine-based in situ shell cross-linking.     

Fabrication of biocompatible magneto-fluorescence nanoparticles as a platform for fluorescent sensor and magnetic hyperthermia applications

Multifunctional nanoparticles with special magnetic and optical properties have been attracting a great deal of attention due to their important applications in the bioanalytical and biomedical fields. In this study, we report the fabrication of biocompatible magneto-fluorescence nanoparticles consisting of carbon dots (CDots) and silica-coated cobalt–manganese nanoferrites (Co_0.5Mn_0.5Fe₂O₄) (CoMnF@Si@CDots) (MagSiCDots) by a facile hydrothermal method. The as-prepared MagSiCDots have a particle size of 100–120 nm and show a negative zeta potential of −35.50 mV at a neutral pH. The fluorescence spectrum of the MagSiCDots nanoparticles consists of sharp excitation at 365 nm and broad blue light emission with a maximum wavelength of 442.5 nm and the MagSiCDots exhibit superparamagnetic behaviour with a saturation magnetization of 11.6 emu g⁻¹. The potential of MagSiCDots as a fluorescent sensor and be used for magnetic hyperthermia applications. It is seen that the fluorescent intensity of a colloidal solution (a hydrogen sulfide (H₂S) solution containing MagSiCDots nanoparticles) has a linear relationship with the H₂S concentration range of 0.2–2 μM. The limit of detection (LOD) of H₂S by our MagSiCDots particles is 0.26 μM and they remain stable for at least 90 min. To test the suitability of the MagSiCDots nanoparticles for use in hyperthermia application, induction heating using an AMF was done. It was observed that these nanoparticles had a specific absorption rate (SAR) of 28.25 W g⁻¹. The in vitro and in vivo cytotoxicity of MagSiCDots were tested on HeLa cells lines. The results show a cell viability of about 85% when exposed to 100 μg mL⁻¹ concentration of the particles. The in vivo cytotoxicity using zebrafish assay also confirmed the non-toxicity and biocompatibility of the nanoparticles to living cells. The reported data demonstrate that by combining CoMnF@Si and fluorescent CDots into a single system, not only nontoxic multifunctional nanomaterials but also multimodal nanoparticles for several applications, such as hazard gas detection and acting as a biocompatible heat source for therapeutic treatment of cancer, are provided.

Multifunctional nanoparticles with special magnetic and optical properties have been attracting a great deal of attention due to their important applications in the bioanalytical and biomedical fields.     

Surface design and preparation of multi-functional magnetic nanoparticles for cancer cell targeting,therapy, and imaging

Recently, theranostic candidates based on superparamagnetic iron oxide nanoparticles (SPIONs) providing the combination of therapy and diagnosis have become one of the most promising system in cancer research. However, poor stability, premature drug release, lack of specific tumor cell targeting, and complicated multi-step synthesis processes still hinder them for potential clinical applications. In this research, the multi-functional magnetic nanoparticles (MNPs-DOX) were prepared via a simple assembly process for targeted delivery of doxorubicin (DOX) and enhanced magnetic resonance (MR) imaging detection. Firstly, the multi-functional copolymer coating, polyamidoamine (PAMAM), was designed and synthesized by Michael addition reaction, where N,N-bis(acryloyl)cystamine served as backbone linker, and DOX, dopamine (DA), and polyethylene glycol (PEG) acted as comonomers. The PAMAM was then directly assembled to the surface of SPIONs by the ligand exchange reaction with SPIONs forming the MNPs-DOX. The hydrophilic PEG moieties provide the nanoparticles with colloidal stability and good-dispersity in aqueous solution. Comparing with the quick release of free DOX, the drug release behavior of MNPs-DOX exhibited a sustained drug release. Because the chemical cleavage of disulfide in the polymer backbone, a high cumulative drug release up to 60% in GSH within 48 h was observed, rather than only 26% in PBS (pH 7.4) without GSH. The MR imaging detection experiment showed that the MNPs-DOX had an enhanced T₂ relaxivity of 126 mM⁻¹ S⁻¹ for MR imaging. The results of the cytotoxicity assays showed a remarkable killing effect of cancer cells by MNPs-DOX due to the FA tumor-targeting ligand, comparing with non-targeted drug molecules. All the results showed that the as prepared multi-functional magnetic nanoparticles may serve as a promising theranostic candidate for targeted anticancer drug delivery and efficient detection through MR imaging in medical application.

Multi-functional magnetic nanoparticles for targeted anticancer drug delivery and efficient MR imaging detection in theranostics.     

Revealing photoluminescence mechanisms of single CsPbBr3/Cs4PbBr6 core/shell perovskite nanocrystals

CsPbBr₃ nanocrystals (NCs) encapsulated by Cs₄PbBr₆ has attracted extensive attention due to good stability and high photoluminescence (PL) emission efficiency. However, the origin of photoluminescence (PL) emission from CsPbBr₃/Cs₄PbBr₆ composite materials has been controversial. In this work, we prepare CsPbBr₃/Cs₄PbBr₆ core/shell nanoparticles and firstly study the mechanism of its photoluminescence (PL) at the single-particle level. Based on photoluminescence (PL) intensity trajectories and photon antibunching measurements, we have found that photoluminescence (PL) intensity trajectories of individual CsPbBr₃/Cs₄PbBr₆ core/shell NCs vary from the uniform longer periods to multiple-step intensity behaviors with increasing excitation level. Meanwhile, second-order photon correlation functions exhibit single photon emission behaviors especially at lower excitation levels. However, the PL intensity trajectories of individual Cs₄PbBr₆ NCs demonstrate apparent “burst-like” behaviors with very high values of g²(0) at any excitation power. Therefore, the distinguishable emission statistics help us to elucidate whether the photoluminescence (PL) emission of CsPbBr₃/Cs₄PbBr₆ core/shell NCs stems from band-edge exciton recombination of CsPbBr₃ NCs or intrinsic Br vacancy states of Cs₄PbBr₆ NCs. These findings provide key information about the origin of emission in CsPbBr₃/Cs₄PbBr₆ core/shell nanoparticles, which improves their utilization in the further optoelectronic applications.

CsPbBr₃/Cs₄PbBr₆ core/shell perovskite NCs were prepared with a cubic shape. The core CsPbBr₃ are coated by a Cs₄PbBr₆ shell. The XRD, absorption spectra and PLE spectra were different from the simple mixtures of CsPbBr₃ and Cs₄PbBr₆ in bulk.     

Ionic magnetic core–shell nanoparticles for DNA extraction

Magnetic nanoparticles with specific surface features are interesting materials for biomedical applications. The combination of molecular interactions on small particles with macroscopic cohesion forces offers unique opportunities. This work reports the synthesis of magnetic core–shell nanoparticles with alkylimidazolium coated surface for effective DNA extraction. A magnetic Fe₂O₃ core was coated with a silica shell and functionalized with an organic halide. This enabled a surface coating with organic cations to mediate effective molecular interactions with polyanionic DNA. The large surface area of the ∼20 nm small particles with a magnetization of 25 emu g⁻¹ enabled high DNA particle loading of 1/30 m% with easy isolation based on an external magnetic field. Moreover, the coating of the particles stabilized DNA against ultrasound initiated fragmentation.

The fabrication ionic magnetic core-shell nanoparticles were simple synthesize with a super-ferromagnetic and small particle size properties, which enabled sufficient DNA particle loading with easy isolation based on an external magnetic field.     

Fabrication of a hyaluronic acid conjugated metal organic framework for targeted drug delivery and magnetic resonance imaging

Since metal organic frameworks (MOF) have exhibited fascinating potential in biomedical applications, it is worthwhile to construct a MOF-based multifunctional drug delivery system. In the present study, the anticancer drug doxorubicin (DOX) was loaded into zeolitic imidazolate framework-8 (ZIF-8) via a one-pot process. The formed DOX@ZIF-8 was then coated with polydopamine, successively chelated with Fe³⁺ and conjugated with hyaluronic acid (HA), finally resulting in a multifunctional ZIF-8 nanocarrier. The characterization results confirmed the successful formation of the hybrid nanocarrier. pH-responsive drug release of DOX was observed due to the innate pH-dependent stability of ZIF-8. Importantly, the flow cytometry and confocal laser scanning microscope results both verified the targeting ability of DOX@ZIF-HA toward prostate cancer PC-3 cells. The improved therapeutic efficacy of DOX@ZIF-HA when compared to the inhibited group was also demonstrated. Furthermore, the chelation of Fe³⁺ by PDA makes the prepared DOX@ZIF-HA a good contrast agent for magnetic resonance (MR) imaging. Hence, we hope the constructed ZIF-8 based multifunctional nanocarrier could be a candidate for cancer theranostics.

DOX-doped MOF nanoparticles were prepared via a one-pot reaction and successively anchored with Fe³⁺ and HA for simultaneous targeted drug delivery and MR imaging.     

A pH and magnetic dual-response hydrogel for synergistic chemo-magnetic hyperthermia tumor therapy

To overcome the toxicity of chemotherapy, increasing attention has been paid to local drug delivery systems (DDSs). pH-Sensitive hydrogels have emerged as promising DDS materials in the biomedical field due to their remarkable characteristics. However, the pH environment in tumor varies from person to person, which makes the applicability of systems based on pH challenging. In this study, we developed a contractible hydroxypropyl methyl cellulose (HPMC)/Fe₃O₄ hydrogel with dual-response pH and magnetic properties aiming to overcome the limitations of pH-sensitive hydrogel drug delivery systems and further increase their efficiency in tumor therapy. The HPMC/Fe₃O₄ hydrogel could act as a drug delivery system that combines pH-sensitive triggering and magnetic dual-response drug release for synergistic chemo-magnetic hyperthermia therapy. The drug delivery profile of the HPMC/Fe₃O₄/doxorubicin hydrochloride (DOX) hydrogel was determined in vitro and revealed a remarkable pH-sensitive performance. After synergistic chemo-magnetic hyperthermia treatment, mice with 4T1 breast cancer xenografts recovered without any recurrence or metastasis, demonstrating the synergistic effect of chemotherapy and magnetic hyperthermia therapy. Meanwhile, reduced toxicity and superior anticancer effects were achieved due to the combined effect of the pH and magnetic hyperthermia response properties. This study demonstrated the high efficacy and low toxicity of the improved design of HPMC/Fe₃O₄ for drug delivery, which may provide a promising approach for the application of chemo-magnetic hyperthermia cancer therapy.

A pH and magnetic dual-responsive hydrogel highly sensitive to tumor acid microenvironment and efficient responsive magnetic-hyperthermia cancer eradication.     

Size-dependent magnetic and magnetothermal properties of gadolinium silicide nanoparticles

Gadolinium silicide (Gd₅Si₄) nanoparticles are an interesting class of materials due to their high magnetization, low Curie temperature, low toxicity in biological environments and their multifunctional properties. We report the magnetic and magnetothermal properties of gadolinium silicide (Gd₅Si₄) nanoparticles prepared by surfactant-assisted ball milling of arc melted bulk ingots of the compound. Using different milling times and speeds, a wide range of crystallite sizes (13–43 nm) could be produced and a reduction in Curie temperature (T_C) from 340 K to 317 K was achieved, making these nanoparticles suitable for self-controlled magnetic hyperthermia applications. The magnetothermal effect was measured in applied AC magnetic fields of amplitude 164–239 Oe and frequencies 163–519 kHz. All particles showed magnetic heating with a strong dependence of the specific absorption rate (SAR) on the average crystallite size. The highest SAR of 3.7 W g⁻¹ was measured for 43 nm sized nanoparticles of Gd₅Si₄. The high SAR and low T_C, (within the therapeutic range for magnetothermal therapy) makes the Gd₅Si₄ behave like self-regulating heat switches that would be suitable for self-controlled magnetic hyperthermia applications after biocompatibility and cytotoxicity tests.

Gadolinium silicide (Gd₅Si₄) nanoparticles prepared by surfactant-assisted ball milling exhibit a size-dependent reduction in magnetic ordering temperature and a high magnetothermal effect making them suitable for magnetic hyperthermia applications.