A phosphorylcholine-based zwitterionic copolymer coated ZIF-8 nanodrug with a long circulation time and charged conversion for enhanced chemotherapy

Drug delivery system based on metal-organic framework improved 5-Fluorouracil against spring viremia of carp virus

Spring viremia of carp virus (SVCV), as a high pathogenicity pathogen, has seriously restricts the healthy and sustainable development of cyprinid farming industry. In this study, we selected 5-Fluorouracil (5-Fu) as the drug model based on zeolitic imidazolate framework-8 (ZIF-8) to construct a drug delivery system (5-Fu@ZIF-8), and the anti-SVCV activity was detected in vitro and in vivo. The results showed 5-Fu@ZIF-8 was uniform cubic particle with truncated angle and smooth surface, and the particle size was 90 nm. The anti-SVCV activity in vitro results showed that the highest inhibition rate of 5-Fu was 77.93% at 40 mg/L and the inhibitory concentration at half-maximal activity (IC50) was 20.86 mg/L. For 5-Fu@ZIF-8, the highest inhibition rate was 91.36% at 16 mg/L, and the IC50 value was 5.85 mg/L. In addition, the cell viability was increased by 18.1% after 5-Fu treatment. Similarly, after 5-Fu@ZIF-8 treatment, the cell viability increased by 27.3%. Correspondingly, in vivo experimental results showed the viral loads reduced by 18.1% on the days 7 and the survival rate increased to 19.4% at 80 mg/L after 5-Fu treatment. For 5-Fu@ZIF-8, the viral loads reduced by 41.2% and the survival rate increased to 54.8%. Mechanistically, 5-Fu inhibits viral replication by regulating p53 expression and promoting early apoptosis in infected cells. All results indicated that 5-Fu@ZIF-8 improved the anti-SVCV activity; it may be a potential strategy to construct a drug-loaded system with ZIF-8 as a carrier for the prevention and treatment of aquatic diseases.

Recent advances of multifunctional zwitterionic polymers for biomedical application

Zwitterionic polymers possess equal total positive and negative charges in the repeating units, making them electrically neutral overall. This unique property results in superhydrophilicity, which makes the zwitterionic polymers highly effective in resisting protein adsorption, thus endowing the drug carriers with long blood circulation time, inhibiting thrombus formation on biomedical devices in contact with blood, and ensuring the good sensitivity of sensors in biomedical application. Moreover, zwitterionic polymers have tumor-targeting ability and pH-responsiveness, rendering them ideal candidates for antitumor drug delivery. Additionally, the high ionic conductivity of zwitterionic polymers makes them an important raw material for ionic skin. Zwitterionic polymers exhibit remarkable resistance to bacterial adsorption and growth, proving their suitability in a wide range of biomedical applications such as ophthalmic applications, and wound dressings. In this paper, we provide an in-depth analysis of the different structures and characteristics of zwitterionic polymers and highlight their unique qualities and suitability for biomedical applications. Furthermore, we discuss the limitations and challenges that must be overcome to realize the full potential of zwitterionic polymers and present an optimistic perspective for zwitterionic polymers in the biomedical fields. STATEMENT OF SIGNIFICANCE: Zwitterionic polymers have a series of excellent properties such as super hydrophilicity, anti-protein adsorption, antibacterial ability and good ionic conductivity. However, biomedical applications of multifunctional zwitterionic polymers are still a major field to be explored. This review focuses on the design and application of zwitterionic polymers-based nanosystems for targeted and responsive delivery of antitumor drugs and cancer diagnostic agents. Moreover, the use of zwitterionic polymers in various biomedical applications such as biomedical devices in contact with blood, biosensors, ionic skin, ophthalmic applications and wound dressings is comprehensively described. We discuss current results and future challenges for a better understanding of multifunctional zwitterionic polymers for biomedical applications.

Enhancing Osteogenic Potential: Controlled Release of Dopamine D1 Receptor Agonist SKF38393 Compared to Free Administration

Osteoporosis is the most common metabolic bone disorder and is characterized by decreased bone density, which has a relationship with the quality of life among the aging population. Previous research has found that activation of the dopamine D1 receptor can improve bone mass formation. SKF38393 is an agonist of dopamine D1 receptors. However, as a small-molecule drug, SKF38393 is unstable and releases quickly. The aim of this study was to prototype polylactic-co-glycolic acid (PLGA)/SKF38393 microspheres and assess their potential osteogenic effects compared to those under the free administration of SKF38393. The cytocompatibility of PLGA/SKF38393 was determined via CCK-8 and live/dead cell staining; the osteogenic effects in vitro were determined with ALP and alizarin red staining, qRT-PCR, and Western blotting; and the in vivo effects were assessed using 25 Balb/c mice. We also used a PCR array to explore the possible signaling pathway changes after employing PLGA/SKF38393. Our experiments demonstrated that the osteogenic effect of D1Rs activated by the PLGA/SKF38393 microsphere was better than that under free administration, both in vitro and in vivo. According to the PCR array, this result might be associated with six signaling pathways (graphical abstract). Ultimately, in this study, we prototyped PLGA/SKF38393, demonstrated its effectiveness, and preliminarily analyzed its mechanism of action.

Hypoxia-activated cascade nanovaccine for synergistic chemoembolization-immune therapy of hepatocellular carcinoma

In this work, a promising treatment strategy for triggering robust antitumor immune responses in transarterial chemoembolization of hepatocellular carcinoma (HCC) is presented. The zeolitic imidazolate framework nanoparticles loaded with hypoxia-activated prodrug tirapazamine and immune adjuvant resiquimod facilitated in situ generation of nanovaccine via a facile approach. The nanovaccine can strengthen the ability of killing the liver cancer cells under hypoxic environment, while was capable of improving immunogenic tumor microenvironment and triggering strong antitumor immune responses by increasing the primary and distant intratumoral infiltration of immune cells such as cytotoxic T cells. Moreover, a porous microcarrier, approved by FDA as pharmaceutical excipient, was designed to achieve safe and effective delivery of the nanovaccine via transarterial therapy in rabbit orthotopic VX2 liver cancer model. The microcarrier exhibited the characteristics of excellent drug loading and occlusion of peripheral artery. The collaborative delivery of the microcarrier and nanovaccine demonstrated an exciting inhibitory effect on solid tumors and tumor metastases, which provided a great potential as novel combination therapy for HCC interventional therapy.

Recent advances in zwitterionic nanoscale drug delivery systems to overcome biological barriers

Nanoscale drug delivery systems (nDDS) have been employed widely in enhancing the therapeutic efficacy of drugs against diseases with reduced side effects. Although several nDDS have been successfully approved for clinical use up to now, biological barriers between the administration site and the target site hinder the wider clinical adoption of nDDS in disease treatment. Polyethylene glycol (PEG)-modification (or PEGylation) has been regarded as the gold standard for stabilising nDDS in complex biological environment. However, the accelerated blood clearance (ABC) of PEGylated nDDS after repeated injections becomes great challenges for their clinical applications. Zwitterionic polymer, a novel family of anti-fouling materials, have evolved as an alternative to PEG due to their super-hydrophilicity and biocompatibility. Zwitterionic nDDS could avoid the generation of ABC phenomenon and exhibit longer blood circulation time than the PEGylated analogues. More impressively, zwitterionic nDDS have recently been shown to overcome multiple biological barriers such as nonspecific organ distribution, pressure gradients, impermeable cell membranes and lysosomal degradation without the need of any complex chemical modifications. The realization of overcoming multiple biological barriers by zwitterionic nDDS may simplify the current overly complex design of nDDS, which could facilitate their better clinical translation. Herein, we summarise the recent progress of zwitterionic nDDS at overcoming various biological barriers and analyse their underlying mechanisms. Finally, prospects and challenges are introduced to guide the rational design of zwitterionic nDDS for disease treatment.

Zeolitic Imidazolate Framework (ZIF-8) Decorated Iron Oxide Nanoparticles Loaded Doxorubicin Hydrochloride for Osteosarcoma Treatment - in vitro and in vivo Preclinical Studies

Background

As a broad-spectrum antitumorigenic agent, doxorubicin (DOX) is commonly used as a chemotherapeutic drug for treating osteosarcoma (OS). Still, it is associated with significant cell toxicity and ineffective drug delivery, whereas the zeolite imidazolate framework is extensively applied in the biomedical field as a carrier owing to its favorable biocompatibility, high porosity, and pH-responsiveness. Therefore, we need to develop a drug delivery platform that can effectively increase the antitumorigenic effect of the loaded drug and concurrently minimize drug toxicity.

Methods

In this study, a Fe3O4@ZIF-8 nanocomposite carrier was prepared with ZIF-8 as the shell and encapsulated with Fe3O4 by loading DOX to form DOX- Fe3O4@ZIF-8 (DFZ) drug-loaded magnetic nanoparticles. Then, we characterized and analyzed the morphology, particle size, and characteristics of Fe3O4@ZIF-8 and DFZ by TEM, SEM, and Malvern. Moreover, we examined the inhibitory effects of DFZ in vitro and in vivo. Meanwhile, we established a tumor-bearing mouse model, evaluating its tumor-targeting by external magnetic field guidance.

Results

DFZ nanoparticles possessed have a size of ~110 nm, with an encapsulation rate of 21% and pH responsiveness. DFZ exerted a superior cytostatic effect and apoptosis rate on K7M2 cells in vitro compared to DOX(p<0.01). In animal experiments, DFZ offers up to 67% tumor inhibition and has shown a superior ability to induce apoptosis than DOX alone in TUNEL results(p<0.01). Tumor-targeting experiments have validated that DFZ can be effectively accumulated in the tumor tissue and enhance anticancer performance.

Conclusion

In summary, the DFZ nano-delivery system exhibited a more substantial anti-tumorigenic effect as well as superior active tumor targeting of DOX- Fe3O4@ZIF-8 compared to that of DOX alone in terms of biocompatibility, drug loading capacity, pH-responsiveness, tumor-targeting, and anti-tumorigenic effect, indicating its chemotherapeutic application potential.

Ferroptosis-enhanced chemotherapy for triple-negative breast cancer with magnetic composite nanoparticles

Triple-negative breast cancer (TNBC) causes great suffering to patients because of its heterogeneity, poor prognosis, and chemotherapy resistance. Ferroptosis is characterized by iron-dependent oxidative damage by accumulating intracellular lipid peroxides to lethal levels, and plays a vital role in the treatment of TNBC based on its intrinsic characteristics. To identify the relationship between chemotherapy resistance and ferroptosis in TNBC, we analyzed the single cell RNA-sequencing public dataset of GSE205551. It was found that the expression of Gpx4 in DOX-resistant TNBC cells was significantly higher than that in DOX-sensitive TNBC cells. Based on this finding, we hypothesize that inducing ferroptosis by inhibiting the expression of Gpx4 can reduce the resistance of TNBC to DOX and enhance the therapeutic effect of chemotherapy on TNBC. Herein, dihydroartemisinin (DHA)-loaded polyglutamic acid-stabilized Fe3O4 magnetic nanoparticles (Fe3O4-PGA-DHA) was combined with DOX-loaded polyaspartic acid-stabilized Fe3O4 magnetic nanoparticles (Fe3O4-PASP-DOX) for ferroptosis-enhanced chemotherapy of TNBC. Compared with Fe3O4-PASP-DOX, Fe3O4-PGA-DHA + Fe3O4-PASP-DOX demonstrated significantly stronger cytotoxicity against different TNBC cell lines and achieved significantly more intracellular accumulation of reactive oxygen species and lipid peroxides. Furthermore, transcriptomic analyses demonstrated that Fe3O4-PASP-DOX-induced apoptosis could be enhanced by Fe3O4-PGA-DHA-induced ferroptosis and Fe3O4-PGA-DHA + Fe3O4-PASP-DOX might trigger ferroptosis in MDA-MB-231 cells by inhibiting the PI3K/AKT/mTOR/GPX4 pathway. Fe3O4-PGA-DHA + Fe3O4-PASP-DOX showed superior anti-tumor efficacy on MDA-MB-231 tumor-bearing mice, providing great potential for improving the therapeutic effect of TNBC.

Oriented ascorbic acid onto zeolitic metal-organic framework-8 membrane via microfluidic spinning for biomedical care

Nowadays, the hydrogen dressing and electrostatic spun films widely used on wounds do not facilitate the permeability of the wound area and fail to achieve controlled drug delivery. Therefore, finding a wound dressing with both breathability and targeted drug delivery has remained an unmet challenge. Here, an oriented microstructure membrane with sustained drug release and robust antibacterial performance was constructed through the microfluidic spinning method. The multifunctional oriented membrane was prepared by loading ascorbic acid onto the zeolitic metal-organic framework-8 to develop drug delivery nanomaterial zeolitic metal-organic framework-8 @ascorbic acid (ZIF-8 @AA) and then mixing ZIF-8 @AA with polyvinyl pyrrolidone (PVP) solution via microfluidic technology, which produced an oriented microfiber member. In addition, the spinning parameters, including the fluid content, rotation speed, and flow rate, on microfiber diameter were evaluated. The constructed oriented membrane had bactericidal efficiencies of 82.94% ± 2.79% and 95.96% ± 1.54% against E. coli and S. aureus, respectively. After five days, the membrane still has a sustained release. Moreover, the fabricated membrane also has good biocompatibility and hemocompatibility in vitro. The oriented arrangement strategy provides a promising approach for wound healing materials in targeted drug delivery. Furthermore, this strategy offers a feasible idea for loading active materials into substrates for disease treatment in the biomedical field.

Vitamin A-modified ZIF-8 lipid nanoparticles for the therapy of liver fibrosis

Liver fibrosis (LF) is one of the major diseases that threaten human health. Until now, no effective drugs have been approved for clinical anti-liver fibrosis treatment. In this study, zeolitic imidazolate framework-8 (ZIF-8) lipid nanoparticles loaded with pirfenidone (PFD) and modified with vitamin A (VA) were constructed (VA-PFD@ZIF-8@DMPC NPs). PFD was embedded in ZIF-8 by the "one-pot" method, and the prepared ZIF-8 had a small particle size (84.3 nm) and high drug loading (54.46%). Moreover, the inherent pH sensitivity of ZIF-8 makes it stable in a normal physiological environment and collapsed in an acidic environment, thus controlling drug release and preventing drug leakage. Besides, the phospholipid layer makes the nano-drug delivery system dispersible and improves its biocompatibility. More importantly, VA is modified on the surface of nanoparticles (NPs), which can target the highly expressed retinol-binding protein receptor (RBPR) on the surface of hepatic stellate cells (HSCs), thereby accurately increasing the local drug concentration at the site of LF. In vivo experiments showed that VA-PFD@ZIF-8@DMPC NPs can reduce liver injury, improve the degree of LF, and exert specific therapeutic effects on LF. In conclusion, this nano-delivery system may become a novel and effective anti-liver fibrosis treatment.

Multifunctional nanostructures: Intelligent design to overcome biological barriers

Over the past three decades, nanoscience has offered a unique solution for reducing the systemic toxicity of chemotherapy drugs and for increasing drug therapeutic efficiency. However, the poor accumulation and pharmacokinetics of nanoparticles are some of the key reasons for their slow translation into the clinic. The is intimately linked to the non-biological nature of nanoparticles and the aberrant features of solid cancer, which together significantly compromise nanoparticle delivery. New findings on the unique properties of tumors and their interactions with nanoparticles and the human body suggest that, contrary to what was long-believed, tumor features may be more mirage than miracle, as the enhanced permeability and retention based efficacy is estimated to be as low as 1%. In this review, we highlight the current barriers and available solutions to pave the way for approved nanoformulations. Furthermore, we aim to discuss the main solutions to solve inefficient drug delivery with the use of nanobioengineering of nanocarriers and the tumor environment. Finally, we will discuss the suggested strategies to overcome two or more biological barriers with one nanocarrier. The variety of design formats, applications and implications of each of these methods will also be evaluated.

Tumor microenvironment responsive T1-T2 dual-mode contrast agent Fe3O4@ZIF-8-Zn-Mn NPs for in vivo magnetic resonance imaging

Activated T₁-T₂ contrast agents can effectively improve the sensitivity and diagnosis accuracy of magnetic resonance imaging (MRI), but the construction of such contrast agents still remains a great challenge. In this work, a pH- and glutathione (GSH)-responsive T₁-T₂ dual-mode contrast agent, Fe₃O₄@ZIF-8-Zn-Mn nanoparticles (NPs), with simple components was constructed via simply assembly of paramagnetic Mn²⁺ ions (as T₁ contrast agent) and Fe₃O₄ NPs (as T₂ contrast agent) into a pH- and GSH-sensitive Zn-zeolitic imidazole framework (ZIF-8) matrix. Under neutral conditions, Fe₃O₄@ZIF-8-Zn-Mn NPs show good stability and weak T₁-T₂ dual-mode MRI contrast effect (r₁ = 0.82 mM^-1 s^-1, r₂ = 21.28 mM^-1 s^-1) due to the magnetic interference between Fe₃O₄ NPs and paramagnetic Mn²⁺ ions. In contrast, under acidic environment (pH = 6.5-5.5) and in the present GSH (0-4 mM), Fe₃O₄@ZIF-8-Zn-Mn NPs can be disassembled and release Fe₃O₄ NPs and paramagnetic Mn²⁺ ions, which causes simultaneous recovery of T₁ and T₂ imaging performances with enhanced r₁ and r₂ relaxation values up to 6.9 and 9.9 times, respectively. Moreover, in vivo MRI experiments showed that after the intravenous injection of Fe₃O₄@ZIF-8-Zn-Mn NPs for about one hour, the T₁-weighted imaging of the tumor site becomes brighter with T₁ signal enhanced by about 31%, while the T₂-weighted imaging of the tumor site becomes darker with T₂ signal enhanced by nearly 30%, suggesting the great potential of Fe₃O₄@ZIF-8-Zn-Mn NPs to be used as a tumor microenvironment-responsive T₁-T₂ dual-mode contrast agent for sensitive tumor imaging.

Aptamer modified Zr-based porphyrinic nanoscale metal-organic frameworks for active-targeted chemo-photodynamic therapy of tumors

Active-targeted nanoplatforms could specifically target tumors compared to normal cells, making them a promising therapeutic agent. The aptamer is a kind of short DNA or RNA sequence that can specifically bind to target molecules, and could be widely used as the active targeting agents of nanoplatforms to achieve active-targeted therapy of tumors. Herein, an aptamer modified nanoplatform DOX@PCN@Apt-M was designed for active-targeted chemo-photodynamic therapy of tumors. Zr-based porphyrinic nanoscale metal organic framework PCN-224 was synthesized through a one-pot reaction, which could produce cytotoxic ¹O₂ for efficient treatment of tumor cells. To improve the therapeutic effect of the tumor, the anticancer drug doxorubicin (DOX) was loaded into PCN-224 to form DOX@PCN-224 for tumor combination therapy. Active-targeted combination therapy achieved by modifying the MUC1 aptamer (Apt-M) onto DOX@PCN-224 surface can not only further reduce the dosage of therapeutic agents, but also reduce their toxic and side effects on normal tissues. In vitro, experimental results indicated that DOX@PCN@Apt-M exhibited enhanced combined therapeutic effect and active targeting efficiency under 808 nm laser irradiation for MCF-7 tumor cells. Based on PCN-224 nanocarriers and aptamer MUC1, this work provides a novel strategy for precisely targeting MCF-7 tumor cells.

Cell-Derived Vesicles for Nanoparticles' Coating: Biomimetic Approaches for Enhanced Blood Circulation and Cancer Therapy

Cancer nanomedicines are designed to encapsulate different therapeutic agents, prevent their premature release, and deliver them specifically to cancer cells, due to their ability to preferentially accumulate in tumor tissue. However, after intravenous administration, nanoparticles immediately interact with biological components that facilitate their recognition by the immune system, being rapidly removed from circulation. Reports show that less than 1% of the administered nanoparticles effectively reach the tumor site. This suboptimal pharmacokinetic profile is pointed out as one of the main factors for the nanoparticles' suboptimal therapeutic effectiveness and poor translation to the clinic. Therefore, an extended blood circulation time may be crucial to increase the nanoparticles' chances of being accumulated in the tumor and promote a site-specific delivery of therapeutic agents. For that purpose, the understanding of the forces that govern the nanoparticles' interaction with biological components and the impact of the physicochemical properties on the in vivo fate will allow the development of novel and more effective nanomedicines. Therefore, in this review, the nano-bio interactions are summarized. Moreover, the application of cell-derived vesicles for extending the blood circulation time and tumor accumulation is reviewed, focusing on the advantages and shortcomings of each cell source.

Nanoscale Zeolitic Imidazolate Framework (ZIF)–8 in Cancer Theranostics: Current Challenges and Prospects

Simple Summary

The biomedical application of metal–organic frameworks in cancer theranostics has become a research hotspot with rapid progress. As a typical representative, ZIF–8 attracts increasing interest from researchers due to its good performance and potential. In this review, we updated recent discoveries on the ZIF–8–based nanoplatforms for cancer, discussed the problems in current research and the obstacles for clinical translation of ZIF–8, and also proposed an outlook on its future development.

Abstract

Cancer severely threatens human health and has remained the leading cause of disease–related death for decades. With the rapid advancement of nanomedicine, nanoscale metal–organic frameworks are believed to be potentially applied in the treatment and biomedical imaging for various tumors. Zeolite imidazole framework (ZIF)–8 attracts increasing attention due to its high porosity, large specific surface area, and pH–responsiveness. The designs and modifications of ZIF–8 nanoparticles, as well as the strategy of drug loading, demand a multifaceted and comprehensive understanding of nanomaterial features and tumor characteristics. We searched for studies on ZIF–8–based nanoplatforms in tumor theranostics on Web of Science from 2015 to 2022, mainly focused on the research published in the past 3 years, summarized the progress of their applications in tumor imaging and treatment, and discussed the favorable aspects of ZIF–8 nanoparticles for tumor theranostics as well as the future opportunities and potential challenges. As a kind of metal–organic framework material full of potential, ZIF–8 can be expected to be combined with more therapeutic systems in the future and continue to contribute to all aspects of tumor therapy and diagnosis.

Zwitterionic polymer coated sorafenib-loaded Fe3O4 composite nanoparticles induced ferroptosis for cancer therapy

Ferroptosis, as a form of cell death different from apoptosis, is very promising for the treatment of cancer in nonapoptotic systems. Since iron is a key component in the induction of ferroptosis in cells, the use of iron-based nanomaterials in treating cancer through ferroptosis is of great significance. Therefore, in this study, magnetic nanoparticles (MNP) were coated with the zwitterionic polymer poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), and then loaded with sorafenib (SRF) to obtain drug-loaded composite nanoparticles MNP@PMPC-SRF. Fe₃O₄ provided a large number of ferric/ferrous ions as an iron source, releasing Fe²⁺ for the regulation of the ferroptosis process and enhancing the effect of the induced cellular ferroptosis on the treatment of colon cancer with SRF. The zwitterionic polymer PMPC effectively extended the blood circulation time, resulting in an enhanced tumor accumulation of the nanodrug. MNP@PMPC-SRF exhibited good biocompatibility for in vivo application and showed an excellent tumor inhibitory effect on HCT116 tumor-bearing nude mice.

Doxorubicin-Loaded Core–Shell UiO-66@SiO2 Metal–Organic Frameworks for Targeted Cellular Uptake and Cancer Treatment

Beneficial features of biocompatible high-capacity UiO-66 nanoparticles, mesoporous SiO₂, and folate-conjugated pluronic F127 were combined to prepare the core–shell UiO-66@SiO₂/F127-FA drug delivery carrier for targeted cellular uptake in cancer treatment. UiO-66 and UiO-66-NH₂ nanoparticles with a narrow size and shape distribution were used to form a series of core–shell MOF@SiO₂ structures. The duration of silanization was varied to change the thickness of the SiO₂ shell, revealing a nonlinear dependence that was attributed to silicon penetration into the porous MOF structure. Doxorubicin encapsulation showed a similar final loading of 5.6 wt % for both uncoated and silica-coated particles, demonstrating the potential of the nanocomposite’s application in small molecule delivery. Silica coating improved the colloidal stability of the composites in a number of model physiological media, enabled grafting of target molecules to the surface, and prevented an uncontrolled release of their cargo, with the drawback of decreased overall porosity. Further modification of the particles with the conjugate of pluronic and folic acid was performed to improve the biocompatibility, prolong the blood circulation time, and target the encapsulated drug to the folate-expressing cancer cells. The final DOX-loaded UiO-66@SiO₂/F127-FA nanoparticles were subjected to properties characterization and in vitro evaluation, including studies of internalization into cells and antitumor activity. Two cell lines were used: MCF-7 breast cancer cells, which have overexpressed folate receptors on the cell membranes, and RAW 264.7 macrophages without folate overexpression. These findings will provide a potential delivery system for DOX and increase the practical value of MOFs.

Functional cRGD-Conjugated Polymer Prodrug for Targeted Drug Delivery to Liver Cancer Cells

To overcome the limitation of conventional nanodrugs in tumor targeting efficiency, coupling targeting ligands to polymeric nanoparticles can enhance the specific binding of nanodrugs to tumors. Cyclo(Arg-Gly-Asp-d-Phe-Lys) (abbreviated as c(RGDfK)) peptide has been widely adopted due to its high affinity to the tumor marker α_vβ₃ integrin receptor. In this study, we develop a cRGD peptide-conjugated camptothecin (CPT) prodrug, which enables self-assembly of nanoparticles for precise targeting and enrichment in tumor tissue. We first synthesized a camptothecin derivative (CPT-ss-N₃) with a reduction-sensitive bond and simultaneously modified PEG to obtain cRGD-PEG-N₃. After ring-opening polymerization of the 2-(but-3-yn-1-yolxy)-2-oxo-1,3,2-dioxaphospholane (BYP), an amphiphilic polymeric prodrug, referred to as cRGD-PEG-g-(PBYP-ss-CPT), was obtained via copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The self-assembly in buffer solution of the cRGD-functional prodrug was studied through DLS and TEM. The in vitro drug release behavior of cRGD-PEG-g-(PBYP-ss-CPT) nanoparticles was investigated. The results show that the nanoparticles are reduction-responsive and the bonded CPT can be released. Endocytosis and MTT assays demonstrate that the cRGD-conjugated prodrug has better affinity for tumor cells, accumulates more intracellularly, and is therefore, more effective. The in vivo drug metabolism studies show that nanoparticles greatly prolong the retention time in circulation. By monitoring drug distribution in tumor and in various tissues, we find that free CPT can be rapidly metabolized, resulting in low accumulation in all tissues. However, cRGD-PEG-g-(PBYP-ss-CPT) nanoparticles accumulate in tumor tissues in higher amounts than PEG-g-(PBYP-ss-CPT) nanoparticles, except for the inevitable capture by the liver. This indicates that the nanomedicine with cRGD has a certain targeting property, which can improve drug delivery efficiency.

Long circulation and tumor-targeting biomimetic nanoparticles for efficient chemo/photothermal synergistic therapy

Photothermal therapy combined with chemotherapy based on nanomedicine has been considered a promising strategy for improving therapeutic efficacy in a tumor. However, nanomedicine can be easily cleared by the immune system without specific surface engineering modifications, thus affecting the ultimate efficacy. Herein, multifunctional biomimetic nanoparticles (Bio-RBCm@PDA@MSN-DOX) with enhanced long circulation and targeting ability are constructed by coating large pore-sized mesoporous silica (MSN) with polydopamine (PDA) layers in a biotin modified red blood cell membrane (Bio-RBCm) for efficient chemo/photothermal synergistic therapy. It is demonstrated that Bio-RBCm@PDA@MSN-DOX presents high photothermal conversion efficiency (40.17%) and enhanced capability to accelerate the release of the anticancer drug (doxorubicin, DOX), thus showing a good synergistic therapeutic effect in cell experiments. More importantly, with the assistance of the biotin and RBC membrane, Bio-RBCm@PDA@MSN-DOX can successfully evade immune clearance and effectively target transport to HeLa tumor sites, finally accomplishing up to 98.95% tumor inhibition with negligible side effects to normal tissues. This multilayer structure presents a valuable model for future therapeutic applications with safe and effective tumor chemotherapy and photothermal therapy.

Microvesicle-camouflaged biomimetic nanoparticles encapsulating a metal-organic framework for targeted rheumatoid arthritis therapy

Background

Methotrexate (MTX) has been highlighted for Rheumatoid arthritis (RA) treatment, however, MTX does not accumulate well at inflamed sites, and long-term administration in high doses leads to severe side effects. In this study, a novel anti-RA nanoparticle complex was designed and constructed, which could improve the targeted accumulation in inflamed joints and reduce side effects.

Results

Here, we prepared a pH-sensitive biomimetic drug delivery system based on macrophage-derived microvesicle (MV)-coated zeolitic imidazolate framework-8 nanoparticles that encapsulated the drug methotrexate (hereafter MV/MTX@ZIF-8). The MV/MTX@ZIF-8 nanoparticles were further modified with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[folate (polyethylene glycol)-2000] (hereafter FPD/MV/MTX@ZIF-8) to exploit the high affinity of folate receptor β for folic acid on the surface of activated macrophages in RA. MTX@ZIF-8 nanoparticles showed high DLE (~ 70%) and EE (~ 82%). In vitro study showed that effective drug release in an acidic environment could be achieved. Further, we confirmed the activated macrophage could uptake much more FPD/MV/MTX@ZIF-8 than inactivated cells. In vivo biodistribution experiment displayed FPD/MV/MTX@ZIF-8 nanoparticles showed the longest circulation time and best joint targeting. Furthermore, pharmacodynamic experiments confirmed that FPD/MV/MTX@ZIF-8 showed sufficient therapeutic efficacy and safety to explore clinical applications.

Conclusions

This study provides a novel approach for the development of biocompatible drug-encapsulating nanomaterials based on MV-coated metal-organic frameworks for effective RA treatment.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01447-0.

Applications of nanocomposites based on zeolitic imidazolate framework-8 in photodynamic and synergistic anti-tumor therapy

Due to the limitations resulting from hypoxia and the self-aggregation of photosensitizers, photodynamic therapy (PDT) has not been applied clinically to treat most types of solid tumors. Zeolitic imidazolate framework-8 (ZIF-8) is a common metal-organic framework that has ultra-high porosity, an adjustable structure, good biocompatibility, and pH-induced biodegradability. In this review, we summarize the applications of ZIF-8 and its derivatives in PDT. This review is divided into two parts. In the first part, we summarize progress in the application of ZIF-8 to enhance PDT and realize theranostics. We discuss the use of ZIF-8 to avoid the self-aggregation of photosensitizers, alleviate hypoxia, increase the PDT penetration depth, and combine PDT with multi-modal imaging. In the second part, we summarize how ZIF-8 can achieve synergistic PDT with other anti-tumor therapies, including chemotherapy, photothermal therapy, chemodynamic therapy, starvation therapy, protein therapy, gene therapy, and immunotherapy. Finally, we highlight the challenges that must be overcome for ZIF-8 to be widely applied in PDT. To the best of our knowledge, this is the first review of ZIF-8-based nanoplatforms for PDT.

Stability of ZIF-8 Nanoparticles in Most Common Cell Culture Media

Zeolite imidazolate framework-8 (ZIF-8) is a promising platform for drug delivery, and information regarding the stability of ZIF-8 nanoparticles in cell culture media is essential for proper interpretation of in vitro experimental results. In this work, we report a quantitative investigation of the ZIF-8 nanoparticle's stability in most common cell culture media. To this purpose, ZIF-8 nanoparticles containing sterically shielded nitroxide probes with high resistance to reduction were synthesized and studied using electron paramagnetic resonance (EPR). The degradation of ZIF-8 in cell media was monitored by tracking the cargo leakage. It was shown that nanoparticles degrade at least partially in all studied media, although the degree of cargo leakage varies widely. We found a strong correlation between the amount of escaped cargo and total concentration of amino acids in the environment. We also established the role of individual amino acids in ZIF-8 degradation. Finally, 2-methylimidazole preliminary dissolved in cell culture media partially inhibits the degradation of ZIF-8 nanoparticles. The guidelines for choosing the proper cell culture medium for the in vitro study of ZIF-8 nanoparticles have been formulated.

ZIF-8 nanoparticles coated with macrophage-derived microvesicles for sustained, targeted delivery of dexamethasone to arthritic joints

Dexamethasone sodium phosphate (Dex) is widely used in the clinic for the treatment of rheumatoid arthritis. However, it circulates in blood for a short time and it is linked to high risk of severe side effects caused by repeated dosing. Here, we encapsulated Dex onto zeolitic imidazolate framework-8 (ZIF-8) to prepare metal-organic framework nanoparticles with high drug loading efficiency. To prevent clearance by the mononuclear phagocyte system and extend time in circulation, the nanoparticles were also camouflaged with macrophage-derived microvesicles (MV) to obtain the biomimetic drug delivery system MV/Dex/ZIF-8. In vitro and in vivo experiments showed that the nanosystem had high drug loading and encapsulation efficiency, high stability, and long circulation time, and it permitted sustained drug release longer in inflamed joint tissues. Our study provides new insights into designing camouflaged drug carriers to prevent their phagocytosis and prolong their time in circulation.

Construction and evaluation of detachable bone-targeting MOF carriers for the delivery of proteasome inhibitors

Tumor bone metastasis is an important cause of tumor recurrence and death. Although bone-targeting nanoparticles decorated with targeting ligands have shown good affinity for bone tissues with the properties of adhesion to the bone matrix, it is not easy to detach from the surface of the bone matrix in the tumor-bone microenvironment, attributed to the robust coordination force between the targeting ligands, such as bisphosphates with bone-deposited calcium. This may hinder the transport of nanoparticles from bone tissue to bone metastatic tumors. In this research, we designed a bone-targeting nanocarrier with detachable bone-targeting character for the therapy of bone metastases. The nanoparticles were constructed by using ZIF-8 and bone-targeting and MMP enzyme sensitive polypeptide-modified hyaluronic acid as a carrier and proteasome inhibitor Bortezomib (BTZ) as cargo. The results show that the constructed D8-M3-HA-ZIF8@BTZ nanoparticles possessed several favorable properties such as good colloidal stability, acid-sensitive drug release, D8 peptide mediated bone targeting and MMP enzyme-responsive desorption. Besides, nanoparticle endocytosis and cytotoxicity were enhanced through HA-mediated targeting to CD44 over-expressing tumor cells. Altogether, this study provides a potential cascade targeting strategy for improving the delivery effects of bone targeted nanoparticles for the delivery of proteasome inhibitors.

Tumor bone metastasis is an important cause of tumor recurrence and death.

Bacteria as Nanoparticle Carriers for Immunotherapy in Oncology

The use of nanocarriers to deliver antitumor agents to solid tumors must overcome biological barriers in order to provide effective clinical responses. Once within the tumor, a nanocarrier should navigate into a dense extracellular matrix, overcoming intratumoral pressure to push it out of the diseased tissue. In recent years, a paradigm change has been proposed, shifting the target of nanomedicine from the tumoral cells to the immune system, in order to exploit the natural ability of this system to capture and interact with nanometric moieties. Thus, nanocarriers have been engineered to interact with immune cells, with the aim of triggering specific antitumor responses. The use of bacteria as nanoparticle carriers has been proposed as a valuable strategy to improve both the accumulation of nanomedicines in solid tumors and their penetration into the malignancy. These microorganisms are capable of propelling themselves into biological environments and navigating through the tumor, guided by the presence of specific molecules secreted by the diseased tissue. These capacities, in addition to the natural immunogenic nature of bacteria, can be exploited to design more effective immunotherapies that yield potent synergistic effects to induce efficient and selective immune responses that lead to the complete eradication of the tumor.

Identification of Nanog as a novel inhibitor of Rad51

To develop inhibitors targeting DNA damage repair pathways is important to improve the effectiveness of chemo- and radiotherapy for cancer patients. Rad51 mediates homologous recombination (HR) repair of DNA damages. It is widely overexpressed in human cancers and overwhelms chemo- and radiotherapy-generated DNA damages through enhancing HR repair signaling, preventing damage-caused cancer cell death. Therefore, to identify inhibitors of Rad51 is important to achieve effective treatment of cancers. Transcription factor Nanog is a core regulator of embryonic stem (ES) cells for its indispensable role in stemness maintenance. In this study, we identified Nanog as a novel inhibitor of Rad51. It interacts with Rad51 and inhibits Rad51-mediated HR repair of DNA damage through its C/CD2 domain. Moreover, Rad51 inhibition can be achieved by nanoscale material- or cell-penetrating peptide (CPP)-mediated direct delivery of Nanog-C/CD2 peptides into somatic cancer cells. Furthermore, we revealed that Nanog suppresses the binding of Rad51 to single-stranded DNAs to stall the HR repair signaling. This study provides explanation for the high γH2AX level in unperturbed ES cells and early embryos, and suggests Nanog-C/CD2 as a promising drug candidate applied to Rad51-related basic research and therapeutic application studies.

Metal-Organic Frameworks and Their Composites Towards Biomedical Applications

Owing to their unique features, including high cargo loading, biodegradability, and tailorability, metal–organic frameworks (MOFs) and their composites have attracted increasing attention in various fields. In this review, application strategies of MOFs and their composites in nanomedicine with emphasis on their functions are presented, from drug delivery, therapeutic agents for different diseases, and imaging contrast agents to sensor nanoreactors. Applications of MOF derivatives in nanomedicine are also introduced. Besides, we summarize different functionalities related to MOFs, which include targeting strategy, biomimetic modification, responsive moieties, and other functional decorations. Finally, challenges and prospects are highlighted about MOFs in future applications.

Monodisperse ZIF-8@dextran nanoparticles co-loaded with hydrophilic and hydrophobic functional cargos for combined near-infrared fluorescence imaging and photothermal therapy

Impressive developments have been achieved with the use of zeolitic imidazolate framework-8 (ZIF-8) as nanocarriers for tumor theranostics in recent decades by incorporating imaging agents and therapeutic drugs within ZIF-8. However, the simultaneous immobilization of hydrophilic and hydrophobic functional molecules into ZIF-8 nanoparticles in water or organic solvents still presents a daunting challenge. Herein, we developed a new synthesis/encapsulation two-in-one (denoted as one-pot) approach to synthesize uniform dextran-modified Cy5.5&ICG@ZIF-8-Dex nanoparticles in DMSO/H₂O solvent mixtures, which enabled the simultaneous encapsulation of hydrophilic indocyanine green (ICG) and hydrophobic cyanine-5.5 (Cy5.5) during the same step. It was confirmed that the one-pot approach in this mixed solvents facilitated the loading of ICG and Cy5.5 molecules. Moreover, the encapsulation of Cy5.5 and ICG within ZIF-8 nanoparticles endowed them with fluorescence imaging capability and photothermal conversion capacity, respectively. The in vivo near-infrared (NIR) fluorescent images of A549-bearing mice injected with Cy5.5&ICG@ZIF-8-Dex demonstrated sufficient accumulations of Cy5.5 at tumor sites due to the enhanced permeability and retention effect. Most impressively, the fluorescent intensity of Cy5.5&ICG@ZIF-8-Dex at tumor site was approximately 40-fold higher than that of free Cy5.5. Additionally, the results of in vivo infrared imaging and photothermal therapy of Cy5.5&ICG@ZIF-8-Dex showed enhanced therapeutic efficiency in comparison with free ICG, further confirming its tumor-targeting capability and photothermal capacity. Therefore, this multifunctional system based on ZIF-8 nanocarriers offered a potential nanoplatform for tumor-targeting theranostics, thus broadening the synthesis and applications of ZIF-8 composite nanoparticles for NIR fluorescence imaging and photothermal therapy in the biomedical field. STATEMENT OF SIGNIFICANCE: Simultaneous immobilization of hydrophilic and hydrophobic molecules into ZIF-8 nanoparticles still remains a daunting challenge. Therefore, we have developed a new synthesis/encapsulation two-in-one approach to synthesize uniform Cy5.5&ICG@ZIF-8-Dex composite nanoparticles in DMSO/H₂O solvent mixtures, which enabled the simultaneous encapsulation of hydrophilic indocyanine green (ICG) and hydrophobic cyanine-5.5 (Cy5.5) functional molecules during a single step. The results showed that the co-loading of Cy5.5 and ICG within the ZIF-8 nanoparticles endowed them with a remarkable fluorescence imaging capability and photothermal conversion capacity. Based on their enhanced convenience and efficacy to simultaneously encapsulate hydrophilic and hydrophobic molecules, the multifunctional nanocarriers that were prepared in the DMSO/H₂O mixed solvents provide a potential nanoplatform toward fluorescence imaging and photothermal therapy for tumor theranostics.

Multifunctional Biomedical Materials Derived from Biological Membranes

The delicate structure and fantastic functions of biological membranes are the successful evolutionary results of a long-term natural selection process. Their excellent biocompatibility and biofunctionality are widely utilized to construct multifunctional biomedical materials mainly by directly camouflaging materials with single or mixed biological membranes, decorating or incorporating materials with membrane-derived vesicles (e.g., exosomes), and designing multifunctional materials with the structure/functions of biological membranes. Here, the structure-function relationship of some important biological membranes and biomimetic membranes are discussed, such as various cell membranes, extracellular vesicles, and membranes from bacteria and organelles. Selected literature examples of multifunctional biomaterials derived from biological membranes for biomedical applications, such as drug- and gene-delivery systems, tissue-repair scaffolds, bioimaging, biosensors, and biological detection, are also highlighted. These designed materials show excellent properties, such as long circulation time, disease-targeted therapy, excellent biocompatibility, and selective recognition. Finally, perspectives and challenges associated with the clinical applications of biological-membrane-derived materials are discussed.

Effects of Zeolite as a Drug Delivery System on Cancer Therapy: A Systematic Review

Zeolites and zeolitic imidazolate frameworks (ZIFs) are widely studied as drug carrying nanoplatforms to enhance the specificity and efficacy of traditional anticancer drugs. At present, there is no other systematic review that assesses the potency of zeolites/ZIFs as anticancer drug carriers. Due to the porous nature and inherent pH-sensitive properties of zeolites/ZIFs, the compounds can entrap and selectively release anticancer drugs into the acidic tumor microenvironment. Therefore, it is valuable to provide a comprehensive overview of available evidence on the topic to identify the benefits of the compound as well as potential gaps in knowledge. The purpose of this study was to evaluate the potential therapeutic applications of zeolites/ZIFs as drug delivery systems delivering doxorubicin (DOX), 5-fluorouracil (5-FU), curcumin, cisplatin, and miR-34a. Following PRISMA guidelines, an exhaustive search of PubMed, Scopus, Embase, and Web of Science was conducted. No language or time limitations were used up to 25th August 2021. Only full text articles were selected that pertained to the usage of zeolites/ZIFs in delivering anticancer drugs. Initially, 1279 studies were identified, of which 572 duplicate records were excluded. After screening for the title, abstract, and full texts, 53 articles remained and were included in the qualitative synthesis. An Inter-Rater Reliability (IRR) test, which included a percent user agreement and reliability percent, was conducted for the 53 articles. The included studies suggest that anticancer drug-incorporated zeolites/ZIFs can be used as alternative treatment options to enhance the efficacy of cancer treatment by mitigating the drawbacks of drugs under conventional treatment.

Zeolitic Imidazolate Framework Platform for Combinational Starvation Therapy and Oxygen Self-Sufficient Photodynamic Therapy against a Hypoxia Tumor

The antitumor efficacy of photodynamic therapy (PDT) is greatly impeded by the nonspecific targeting of photosensitizers and limited oxygen supply in hypoxic tumors. Aiming to overcome the problem, a dual-locked porphyrin/enzyme-loading zeolitic imidazolate framework (ZIF) nanoplatform was constructed for starvation therapy and O₂ self-sufficient PDT. The fluorescence recovery and PDT of photosensitizers could be cooperatively triggered by dual pathological parameters, the low pH and overexpressed GSH in tumor tissues, which makes the PDT process conduct precisely in a tumor microenvironment. The cascade catalysis of glucose oxidase and catalase promotes the nanoplatform dissociation, inhibits the energy supply of tumors (starvation therapy), and provides enough O₂ to ameliorate the hypoxia and enhance PDT efficacy. In vitro and in vivo studies were performed to confirm the high antitumor efficacy of the porphyrin/enzyme-loading ZIF nanoplatform. Thus, this work offers a path for precise and efficient PDT-based combination therapy against a hypoxia tumor.

Biocompatibility and biodegradability of metal organic frameworks for biomedical applications

Metal organic frameworks (MOFs) are a unique class of smart hybrid materials that have recently attracted significant interest for catalysis, separation and biomedical applications. Different strategies have been developed to overcome the limitations of MOFs for bio-applications in order to produce a system with high biocompatibility and biodegradability. In this review, we outline the chemical and physical factors that dictate the biocompatibility and biodegradability characteristics of MOFs including the nature of the metal ions and organic ligands, size, surface properties and colloidal stability. This review includes the in vitro biodegradation and in vivo biodistribution studies of MOFs to better understand their pharmacokinetics, organ toxicity and immune response. Such studies can guide the design of future bio-friendly systems that bring us closer to safely translating these platforms into the pharmaceutical consumer market.