Smart Self-Assembled Nanosystem Based on Water-Soluble Pillararene and Rare-Earth-Doped Upconversion Nanoparticles for pH-Responsive Drug Delivery

Fabricating β-cyclodextrin based pH-responsive nanotheranostics as a programmable polymeric nanocapsule for simultaneous diagnosis and therapy

Background

Fabrication of a smart drug delivery system that could dramatically increase the efficiency of chemotherapeutic drugs and reduce the side effects is still a challenge for pharmaceutical researchers. By the emergence of nanotechnology, a huge window was opened towards this goal, and a wide type of nanocarriers were introduced for delivering the chemotherapeutic to the cancer cells, among them are cyclodextrins with the ability to host different types of hydrophobic bioactive molecules through inclusion complexation process.

Aim

The aim of this study is to design and fabricate a pH-responsive theranostic nanocapsule based on cyclodextrin supramolecular nano-structure.

Materials and methods

This nanostructure contains iron oxide nanoparticles in the core surrounded with three polymeric layers including polymeric β-cyclodextrin, polyacrylic acid conjugated to sulfadiazine, and polyethylenimine functionalized with β-cyclodextrin. Sulfadiazine is a pH-responsive hydrophobic component capable of making inclusion complex with β-cyclodextrin available in the first and third layers. Doxorubicin, as an anti-cancer drug model, was chosen and the drug loading and release pattern were determined at normal and acidic pH. Moreover, the biocompatibility of the nanocapsule (with/without drug component) was examined using different techniques such as MTT assay, complement activation, coagulation assay, and hemolysis.

Results

The results revealed the successful preparation of a spherical nanocapsule with mean size 43±1.5 nm and negatively charge of −43 mV that show 160% loading efficacy. Moreover, the nanocapsule has an on/off switching release pattern in response to pH that leads to drug released in low acidic pH. The results of the biocompatibility tests indicated that this nano drug delivery system had no effect on blood and immune components while it could affect cancer cells even at very low concentrations (0.3 μg mL⁻¹).

Conclusion

The obtained results suggest that this is a “switchable” theranostic nanocapsule with potential application as an ideal delivery system for simultaneous cancer diagnosis and therapy.

Doxorubicin/cisplatin co-loaded hyaluronic acid/chitosan-based nanoparticles for in vitro synergistic combination chemotherapy of breast cancer

Combination chemotherapy has attracted more and more attention in the field of anticancer treatment. Herein, a synergetic targeted combination chemotherapy of doxorubicin (DOX) and cisplatin in breast cancer was realized by HER2 antibody-decorated nanoparticles assembled from aldehyde hyaluronic acid (AHA) and hydroxyethyl chitosan (HECS). Cisplatin and DOX were successively conjugated onto AHA through chelation and Schiff's base reaction, respectively, forming DOX/cisplatin-loaded AHA inner core. The core was sequentially complexed with HECS and targeting HER2 antibody-conjugated AHA. The formed near-spherical nanoplatform had an average size of ∼160 nm and a zeta potential of -28 mV and displayed pH-responsive surface charge reversal and drug release behaviors. HER2 receptor-mediated active targeting significantly enhanced the cellular uptake of nanoplatform. Importantly, DOX and cisplatin exhibited a synergistic cell-killing effect in human breast cancer MCF-7 cells. These results clearly indicate that the novel nanoplatform is promising for synergistic combination chemotherapy of breast cancer.

Recognition Selectivities of Lasso-Type Pseudo[1]rotaxane Based on a Mono-Ester-Functionalized Pillar[5]arene

Two types of mono-ester-functionalized pillar[5]arenes, P1 and P2, bearing different side-chain groups, were synthesized. Their host–guest complexation and self-inclusion properties were studied by ¹H NMR and 2D nuclear overhauser effect spectroscopy (NOESY) NMR measurements. The results showed that the substituents on their phenolic units have a great influence on the self-assembly of both pillar[5]arenes, although they both could form stable pseudo[1]rotaxanes at room temperature. When eight bulky 4-brombutyloxy groups were capped on the cavity, instead of methoxy groups, pseudo[1]rotaxane P1 became less stable and its locked ester group in the inner space of cavity was not as deep as P2, leading to distinctly different host–guest properties between P1 and P2 with 1,6-dibromohexane. Moreover, pillar[5]arene P1 displayed effective molecular recognition toward 1,6-dichlorohexane and 1,2-bromoethane among the guest dihalides. In addition, the self-complex models and stabilities between P1 and P2 were also studied by computational modeling and experimental calculations.

Supramolecular nanotheranostics based on pillarenes

With the rapid development of supramolecular chemistry and nanomaterials, supramolecular nanotheranostics has attracted remarkable attention owing to the advantages compared with conventional medicine. Supramolecular architectures relying on non-covalent interactions possess reversible and stimuli-responsive features; endowing supramolecular nanotheranostics based on supramolecular assemblies great potentials for the fabrication of integrated novel nanomedicines and controlled drug delivery systems. In particular, pillarenes, as a relatively new class of synthetic macrocycles, are important candidates in the construction of supramolecular therapeutic systems due to their excellent features such as rigid and symmetric structures, facile substitution, and unique host-guest properties. This review summarizes the development of pillarene-based supramolecular nanotheranostics for applications in biological mimicking, virus inhibition, cancer therapy, and diagnosis, which contains the following two major parts: (a) pillarene-based hybrid supramolecular nanotheranostics upon hybridizing with porous materials such as mesoporous silica nanoparticles, metal-organic frameworks, metal nanoparticles, and other inorganic materials; (b) pillarene-based organic supramolecular therapeutic systems that include supramolecular amphiphilic systems, artificial channels, and prodrugs based on host-guest complexes. Finally, perspectives on how pillarene-based supramolecular nanotheranostics will advance the field of pharmaceuticals and therapeutics are given.

Precisely tailored shell thickness and Ln3+ content to produce multicolor emission from Nd3+-sensitized Gd3+-based core/shell/shell UCNPs through bi-directional energy transfer

Lanthanide (Ln³⁺)-doped upconversion nanoparticles (UCNPs) have been paid great attention as multiplexing agents due to their numerous uses in biological and clinical applications such as bioimaging and magnetic resonance imaging (MRI), to name a few. To achieve efficient multicolor emission from UCNPs under single 808 nm excitation and avoid detrimental cross-relaxations between the Ln³⁺ activator ions (positioned in either the core and/or shell in the core/shell), it is essential to design an adequate nanoparticle architecture. Herein, we demonstrate the tailoring of multicolor upconversion luminescence (UCL) from Nd³⁺-sensitized Gd³⁺-based core/shell/shell UCNPs with an architecture represented as NaGdF₄:Tm³⁺(0.75)/Yb³⁺(40)/Ca²⁺(7)/Nd³⁺(1)@NaGdF₄:Ca²⁺(7)/Nd³⁺(30)@NaGdF₄:Yb³⁺(40)/Ca²⁺(7)/Nd³⁺(1)/Er³⁺(X = 1, 2, 3, 5, 7) [hereafter named CSS (Er³⁺ = 1, 2, 3, 5 and 7 mol%)]. Such UCNPs can be excited at a single wavelength (∼808 nm) without generation of any local heat. Incorporation of substantial Nd³⁺-sensitizers with an appropriate concentration in the middle layer allows efficient harvesting of excitation light which migrates bi-directionally across the core/shell interfaces in sync to produce blue emission from Tm³⁺ (activator) ions in the core as well as green and red emission from Er³⁺ (activator) ions in the outermost shell. Introduction of Ca²⁺ lowers the local crystal field symmetry around Ln³⁺ ions and subsequently affects their intra 4f-4f transition probability, thus enhancing the upconversion efficiency of the UCNPs. By simple and precise control of the shell thickness along with tuning the content of Ln³⁺ ions in each domain, multicolor UCL can be produced, ranging from blue to white. We envision that our sub-20 nm sized Nd³⁺-sensitized Gd³⁺-based UCNPs are not only potential candidates for a variety of multiplexed biological applications (without impediment of any heating effect), but also can act as MRI contrast agents in clinical diagnosis.

Renal Clearable Bi-Bi2S3 Heterostructure Nanoparticles for Targeting Cancer Theranostics

Recent development of precise nanomedicine has aroused an overwhelming interest in integration of diagnosis and treatment for cancers. Designing renal-clearable and targeting nanoparticles (NPs) has specific cancer theranostic implications and remains a challenging task. In this work, the ultrasmall folic acid (FA) and bovine serum albumin-modified Bi-Bi₂S₃ heterostructure nanoparticles NPs (Bi-Bi₂S₃/BSA&FA NPs) with excellent computed tomography (CT) and photoacoustic imaging abilities and outstanding photothermal performances were synthesized in an aqueous phase route via a simple method. Bi-Bi₂S₃/BSA&FA NPs have the following criteria: (i) Bi-Bi₂S₃/BSA&FA NPs with heterostructure possess better stability than Bi NPs and higher Bi content than Bi₂S₃ NPs, which are conducive to the enhancement of CT imaging effect; (ii) Bi-Bi₂S₃/BSA&FA NPs with FA molecules on the surface could target the tumor site effectively; (iii) Bi-Bi₂S₃/BSA&FA NPs could inhibit tumor growth effectively under 808 nm laser irradiation; (iv) ultrasmall Bi-Bi₂S₃/BSA&FA NPs could be cleared through kidney and liver within a reasonable time, avoiding a long-term retention/toxicity. Therefore, the renal clearable Bi-Bi₂S₃/BSA&FA NPs are a promising agent for targeting cancer theranostics.

FRET-Based Upconversion Nanoprobe Sensitized by Nd3+ for the Ratiometric Detection of Hydrogen Peroxide in Vivo

The exorbitant level of hydrogen peroxide is closely related to many human diseases. The development of novel probes for H₂O₂ detection will be beneficial to disease diagnosis. In this study, a novel Nd³⁺-sensitized upconversion nanoprobe based on Förster resonance energy transfer was first developed for sensing H₂O₂. This nanosystem was made of core-shell upconversion nanoparticles (emission at 540 and 660 nm), dicyanomethylene-4 H-pyran (DCM)-H₂O₂, and poly acrylic acid (PAA)-octylamine. Obviously, upconversion nanoparticles (UCNPs) doped with Nd³⁺ acted as an energy donor, and DCM-H₂O₂, transferring to DCM-OH with the reaction of H₂O₂, acted as an energy acceptor. The ratiometric upconversion luminescence (540 nm/660 nm) signal could be utilized to visualize the H₂O₂ level, and the LOD of the nanoprobe for H₂O₂ was quantified to be 0.168 μM. Meanwhile, owing to the dope of Nd³⁺, the nanoprobe would not induce the overheating effect in biological samples and could possess deeper tissue penetration depth, compared with the UCNPs excited by 980 nm light during bioimaging. The nanoprobe could also play an important role in detecting the exogenous and endogenous H₂O₂ in living cells with ratiometric UCL (upconversion luminescence) imaging. Furthermore, our nanoprobe could function in detecting the H₂O₂ in a tumor-bearing mouse model. Therefore, this novel nanoprobe along with the ratiometric method for responding and bioimaging H₂O₂ could serve as a new model that promotes the emergence of novel probes for H₂O₂ detection.

The chiral interfaces fabricated by d/l-alanine-pillar[5]arenes for selectively adsorbing ctDNA

In this paper, the d/l-AP5-interfaces are firstly fabricated by attaching d-alanine-pillar[5]arene and l-alanine-pillar[5]arene (d/l-AP5) onto the gold surface, and they exhibit a significantly different chiral influence on the morphology and the adsorption quantity of the adsorbed ctDNA molecules. The research provides an ideal chiral platform for investigating chiral phenomena in biological systems.

Redox and pH responsive polymeric vesicles constructed from a water-soluble pillar[5]arene and a paraquat-containing block copolymer for rate-tunable controlled release

Herein, for rate-tunable controlled release, pH and redox dual responsive polymeric vesicles were constructed based on host-guest interaction between a water soluble pillar[5]arene (WP5) and a paraquat-containing block copolymer (BCP) in water. The yielding polymeric vesicles can be further applied in the controlled release of a hydrophilic model drug, doxorubicin hydrochloride (DOX). The drug release rate is regulated depending on the type of single stimulus or the combination of two stimuli. Meanwhile, DOX-loaded polymeric vesicles present anticancer activity in vitro comparable to free DOX under the studied conditions, which may be important for applications in the therapy of cancers as a controlled-release drug carrier.

Stimuli-responsive supramolecular nano-systems based on pillar[n]arenes and their related applications

Stimuli-responsive supramolecular nano-systems (SRNS) have been a trending interdisciplinary research area due to the responsiveness upon appropriate stimuli, which makes SRNS very attractive in multiple fields where precise control is vital.

A dual-targeted hyaluronic acid-gold nanorod platform with triple-stimuli responsiveness for photodynamic/photothermal therapy of breast cancer

Multi-stimuli-responsive theranostic nanoplatform integrating functions of both imaging and multimodal therapeutics holds great promise for improving diagnosis and therapeutic efficacy. In this study, we reported a pH, glutathione (GSH) and hyaluronidase (HAase) triple-responsive nanoplatform for HER2 and CD44 dual-targeted and fluorescence imaging-guided PDT/PTT dual-therapy against HER2-overexpressed breast cancer. The nanoplatform was fabricated by functionalizing gold nanorods (GNRs) with hyaluronic acid (HA) bearing pendant hydrazide and thiol groups via Au-S bonds, and subsequently chemically conjugating 5-aminolevulinic acid (ALA), Cy7.5 and anti-HER2 antibody onto HA moiety for PDT, fluorescence imaging and active targeting, respectively. The resulting versatile nanoplatform GNR-HA^-ALA/Cy7.5-HER2 had uniform sizes, favorable dispersibility, as well as pH, GSH and HAase triple-responsive drug release manner. In vitro studies demonstrated that HER2 and CD44 receptor-mediated dual-targeting strategy could significantly enhance the cellular uptake of GNR-HA^-ALA/Cy7.5-HER2. Under near-infrared (NIR) irradiation, MCF-7 cells could efficiently generate reactive oxygen species (ROS) and heat, and be more efficiently killed by a combination of PDT and PTT as compared with individual therapy. Pharmacokinetic and biodistribution studies showed that the nanoplatform possessed a circulation half-life of 1.9 h and could be specifically delivered to tumor tissues with an accumulation ratio of 12.8%. Upon the fluorescence imaging-guided PDT/PTT treatments, the tumors were completely eliminated without obvious side effects. The results suggest that the GNR-HA^-ALA/Cy7.5-HER2 holds great potential for breast cancer therapy. STATEMENT OF SIGNIFICANCE: A combination of photodynamic therapy (PDT) and photothermal therapy (PTT) is emerging as a promising cancer treatment strategy. However, its therapeutic efficacy is compromised by the nonspecific delivery and unintended release of photo-responsive agents. Herein, we developed a multifunctional theranostic nanoplatform GNR-HA^-ALA/Cy7.5-HER2 with pH, glutathione and hyaluronidase triple-responsive drug release for HER2 and CD44 dual-targeted and fluorescence imaging-guided PDT/PTT therapy against breast cancer. We demonstrated that HER2 and CD44 receptors-mediated dual-targeting strategy significantly enhanced the cellular uptake of GNR-HA^-ALA/Cy7.5-HER2. We also demonstrated that the combined PDT/PTT treatment had significantly superior antitumor effect than PDT or PTT alone both in vitro and in vivo. Therefore, GNR-HA^-ALA/Cy7.5-HER2 could serve as a promising nanoplatform for HER2-positive breast cancer therapy.

Supramolecular delivery systems based on pillararenes

Supramolecular delivery systems (SDSs) fabricated via molecular assembly, which conveniently allow integration of multiple functions in a single system and structural diversity of systems, are a very active research area due to their enormous potential in biomedical applications, including drug delivery, cell imaging, diagnosis, and release monitoring. Pillararenes, a novel type of macrocyclic molecule, are gaining increasing interest as an important component in the construction of SDSs due to their unique structural and chemical properties. This feature article summarizes pillararene-based SDSs constructed via host-guest interactions via four strategies: (1) supramolecular host-guest complexation; (2) self-assembly of supramolecular amphiphiles; (3) self-assembly of amphiphilic supramolecular polymer conjugates; (4) hybridization with other porous materials, such as inorganic materials and metal-organic frameworks (MOFs). The various SDSs based on pillararenes for the delivery of different cargoes from anti-cancer drugs, fluorescent molecules, siRNAs, and insulin to antibiotics are reviewed. Furthermore, future challenges for advanced SDSs based on pillararenes and their broader applications are outlined.

Multi-stimuli-responsive supramolecular gel constructed by pillar[5]arene-based pseudorotaxanes for efficient detection and separation of multi-analytes in aqueous solution

Here, a novel pseudorotaxanes-type crosslinker of a supramolecular polymer network (WP5-PN) has been constructed from a host water-soluble pillar[5]arene (WP5) and a guest naphthalene dimethylamine derivative (PN) via a stepwise process involving multiple non-covalent interactions. The obtained supramolecular polymers were able to transform into a supramolecular polymer gel (WP5-PN-G) and show AIE properties in DMSO-H2O binary solution. Interestingly, due to the dynamic and reversible nature of non-covalent interactions, the resultant supramolecular polymer gels exhibited external stimuli-responsiveness to different parameters, such as temperature, acid-base, competitive guest and mechanical stress. Moreover, WP5-PN-G showed fluorescent response for Fe3+ and Cu2+, while its xerogel showed excellent recyclable separation properties for these metal ions with adsorption rates up to 98.07% and 95.38%, respectively. Moreover, by rational introduction of these metal ions into the WP5-PN-G, corresponding metal ion coordinated metallogels, such as WP5-PN-FeG and WP5-PN-CuG were obtained. These metallogels could selectively and sensitively sense F- and CN-, respectively. The detection limits of these metallogels for F- and CN- were about 1 × 10-8 M. The WP5-PN-G has potential applications in multi-analytes detection and separation as well as fluorescent display materials.

Honeycomb-Satellite Structured pH/H2O2-Responsive Degradable Nanoplatform for Efficient Photodynamic Therapy and Multimodal Imaging

The oxygen-deprived environment of a solid tumor is still great restriction in achieving an efficient photodynamic therapy (PDT). In this work, we developed a smart pH-controllable and H₂O₂-responsive nanoplatform with degradable property, which was based on honeycomb manganese oxide (hMnO₂) nanospheres loaded with Ce6-sensitized core-shell-shell structured up-conversion nanoparticles (NaGdF₄:Yb/Er,Tm@NaGdF₄:Yb@NaNdF₄:Yb) (abbreviated as hMUC). In the system, the speedy breakup of the as-prepared hMnO₂ nanostructures results in release of loaded Ce6-sensitized UCNPs under the condition of H₂O₂ in acid solution. When exposed to tissue-penetrable 808 nm laser, up-conversion nanoparticles (UCNPs) emit higher-energy visible photons which would be absorbed by Ce6 to yield cytotoxic reactive oxygen species (ROS), thus triggering PDT treatment naturally. Moreover, the in vitro and in vivo experiments demonstrate that hMUC sample with the honeycomb-satellite structure can serve as multimodal bioimaging contrast agent for self-enhanced upconversion luminescence (UCL), magnetic resonance imaging (MRI) and computed tomography (CT) imaging, indicating that the as-prepared hMUC could be used in imaging-guided diagnosis and treatment, which has a potential application in the PDT treatment of tumor.

Recent Advances in Functional-Polymer-Decorated Transition-Metal Nanomaterials for Bioimaging and Cancer Therapy

In this review, we focus on recent advances in the synthesis of polymer-functionalized transition-metal-based nanomaterials and follow this up by discussing their applications in bioimaging diagnosis and cancer therapy. Transition-metal-based nanomaterials show great potential in cancer therapy owing to their intensive near-IR absorption, excellent photothermal conversion efficiency, strong X-ray attenuation, and magnetic properties. Functional polymers are usually introduced by a one-step or multistep method to further endow these nanomaterials with great biocompatibility and physiological stability. Polymer-decorated transition-metal nanomaterials show great potential in multimodal imaging diagnosis (photoacoustic imaging, computed tomography, photoluminescence imaging, positron emission tomography, etc.) and cancer therapy (chemotherapy, photothermal therapy, microwave therapy, radiotherapy, photodynamic therapy). At the end of this review, the prospects of these polymer-decorated transition-metal-based nanomaterials are also discussed.

Supramolecular Nanosystem Based on Pillararene-Capped CuS Nanoparticles for Targeted Chemo-Photothermal Therapy

A smart supramolecular nanosystem integrating targeting, chemotherapy, and photothermal therapy was constructed based on carboxylatopillar[5]arene (CP[5]A)-functionalized CuS nanoparticles (CuS@CP NPs). CuS@CP NPs with good monodispersibility and strong near-infrared absorption were synthesized in aqueous solution through a facile one-pot supramolecular capping method, followed by surface installation of a liver cancer-targeted galactose derivative through host-guest binding interaction. The resulting smart supramolecular nanosystem, namely, CuS@CPG, exhibited excellent photothermal ablation capability to HepG2 cells upon irradiation with laser at 808 nm. Chemotherapeutic drug, doxorubicin hydrochloride (DOX), was further loaded on CuS@CPG via electrostatic interactions between positively charged DOX and negatively charged CP[5]A to give CuS@CPG-DOX with a high drug-loading capacity up to 48.4%. The weakening of DOX-CP[5]A interactions in an acidic environment promoted the pH-responsive drug release from CuS@CPG-DOX. Significantly, this multifunctional supramolecular nanosystem showed a remarkably enhanced therapeutic effect through the combination of targeted chemotherapy and photothermal therapy upon in vitro cell study. Moreover, preliminary in vivo study demonstrated that CuS@CPG and CuS@CPG-DOX had good biocompatibility and excellent tumor inhibition effects upon near-infrared laser irradiation.

Sandwich DNA Hybridization Fluorescence Resonance Energy-Transfer Strategy for miR-122 Detection by Core-Shell Upconversion Nanoparticles

An upconversion nanoparticle (UCNP)-based fluorescence resonance energy-transfer (FRET) strategy is normally restricted by the complicated preparations, low energy-transfer efficiency, and the challenge on improving specificity. Herein, simple DNA-functionalized UCNPs were designed as energy donors for constructing a FRET-based probe to detect the liver-specific microRNA 122 (miR-122). To improve FRET efficiency, UCNPs were constructed with confined core-shell structures, in which emitting ions were precisely located in the thin shell to make them close enough to external energy acceptors. Subsequently, capture DNA was simply functionalized on the outer surface of UCNPs based on ligand exchange that contributed to shortening the energy-transfer distance without extra modification. To gain high specificity, the donor-to-acceptor distance of FRET was controlled by a sandwich DNA hybridization structure using two shorter DNAs with designed complementary sequences (capture DNA and dye-labeled report DNA) to capture the longer target of miR-122. Therefore, the sensitive detection of miR-122 was achieved based on the decreased signals of UCNPs and the increased signals of the dye labeled on reported DNA. With good biocompatibility, this method has been further applied to cancer cell imaging and in vivo imaging, which opened up a new avenue to the sensitive detection and imaging of microRNA in biological systems.

Renal-Clearable Peptide-Functionalized Ba2GdF7 Nanoparticles for Positive Tumor-Targeting Dual-Mode Bioimaging

Considering the dilemma between the effective tumor targeting and the avoidance of potential toxicity, it is desired to design nanoprobes with positive tumor-targeting and good renal clearance ability. In the present work, we developed epidermal growth factor receptor (EGFR)-targeted peptide-functionalized Ba₂GdF₇ nanoparticles (termed as pEGFR-targeted Ba₂GdF₇ NPs) for positive tumor-targeting magnetic resonance imaging and X-ray computed tomography (MRI/CT) dual-mode bioimaging. The positive tumor-targeting ability of pEGFR-targeted Ba₂GdF₇ NPs is achieved by conjugation of EGFR-targeted peptides on the 6.5 nm Ba₂GdF₇ NP surface through the formation of Gd-phosphonate coordinate bonds. The pEGFR-targeted Ba₂GdF₇ NPs display desirable cytocompatibility in the test concentration range and high binding affinity with lung cancer cells. In vivo MR and CT imaging results demonstrate that the pEGFR-targeted Ba₂GdF₇ NPs are able to be accumulated and detained within an engrafted A549 lung carcinoma, which enhances both MR and CT contrast in the tumor tissue. Systematic in vivo experimental results further demonstrate that the pEGFR-targeted Ba₂GdF₇ NPs have favorable in vivo renal clearance kinetics as well as reasonable in vivo biocompatibility.

Surfactant-free aqueous synthesis of novel Ba3Gd2F12:Ln3+ nanocrystals with luminescence properties

Novel Ba₃Gd₂F₁₂:Ln³⁺ (Ln = Eu, Dy, Tb, Ce, Er, Tm, and Yb) nanocrystals with multicolor emissions have been prepared via a surfactant-free aqueous hydrothermal route for the first time.

Facile surface functionalization of upconversion nanoparticles with phosphoryl pillar[5]arenes for controlled cargo release and cell imaging

A new organic–inorganic hybrid material based on upconversion nanoparticles and pillarenes is constructed for cargo controlled delivery and cell imaging.

A bis-naphthalimide functionalized pillar[5]arene-based supramolecular π-gel acts as a multi-stimuli-responsive material

A novel approach for the design of multi-stimuli-responsive supramolecular functional materials was successfully developed by introducing the competition of π–π stacking and cation–π interactions into a pillar[5]arene-based supramolecular π-gel (MP5-G).