A metal-organic framework based inner ear delivery system for the treatment of noise-induced hearing loss

Enhanced lysosomal escape of cell penetrating peptide-functionalized metal-organic frameworks for co-delivery of survivin siRNA and oridonin

In recent years, small interfering RNA (siRNA) has been widely used in the treatment of human diseases, especially tumors, and has shown great appeal. However, the clinical application of siRNA faces several challenges. Insufficient efficacy, poor bioavailability, poor stability, and lack of responsiveness to a single therapy are the main problems affecting tumor therapy. Here, we designed a cell-penetrating peptide (CPP)-modified metal organic framework nanoplatform (named PEG-CPP33@ORI@survivin siRNA@ZIF-90, PEG-CPP33@NPs) for targeted co-delivery of oridonin (ORI), a natural anti-tumor active ingredient) and survivin siRNA in vivo. This can improve the stability and bioavailability of siRNA and the efficacy of siRNA monotherapy. The high drug-loading capacity and pH-sensitive properties of zeolite imidazolides endowed the PEG-CPP33@NPs with lysosomal escape abilities. The Polyethylene glycol (PEG)-conjugated CPP (PEG-CPP33) coating significantly improved the uptake in the PEG-CPP33@NPs in vitro and in vivo. The results showed that the co-delivery of ORI and survivin siRNA greatly enhanced the anti-tumor effect of PEG-CPP33@NPs, demonstrating the synergistic effect between ORI and survivin siRNA. In summary, the novel targeted nanobiological platform loaded with ORI and survivin siRNA presented herein showed great advantages in cancer therapy, and provides an attractive strategy for the synergistic application of chemotherapy and gene therapy.

Preservation of Proteins in Human Plasma through Metal-Organic Framework Encapsulation

Traditional cold chain systems of collection, transportation, and storage of biofluid specimens for eventual analysis pose a huge financial and environmental burden. These systems are impractical in pre-hospital and resource-limited settings, where refrigeration and electricity are not reliable or even available. Here, we develop an innovative technology using metal-organic frameworks (MOFs), a novel class of organic-inorganic hybrids with high thermal stability, as encapsulates for preserving the integrity of protein biomarkers in biofluids under ambient or non-refrigerated storage conditions. We encapsulate prostate-specific antigen (PSA) in whole patient plasma using hydrophilic zeolitic imidazolate framework-90 (ZIF-90) for preservation at 40 °C for 4 weeks and eventual on-demand reconstitution for antibody-based assays with recovery above 95% compared to storage at -20 °C. Without ZIF-90 encapsulation, only 10-30% of the PSA immunoactivity remained. Furthermore, we demonstrate encapsulation of multiple cancer biomarker proteins in whole patient plasma using ZIF-8 or ZIF-90 encapsulants for eventual on-demand reconstitution and analysis after 1 week at 40 °C. Overall, MOF encapsulation of patient biofluids is important as climate change may be affecting the stability and increase costs of maintaining biospecimen cold chain custody for the collection, transportation, and storage of biospecimens prior to analysis or for biobanking regardless of any countries' affluence.

Potential nanotechnology-based diagnostic and therapeutic approaches for Meniere's disease

Meniere's disease (MD) is a progressive inner ear disorder involving recurrent and prolonged episodes or attacks of vertigo with associated symptoms, resulting in a significantly reduced quality of life for sufferers. In most cases, MD starts in one ear; however, in one-third of patients, the disorder progresses to the other ear. Unfortunately, the etiology of the disease is unknown, making the development of effective treatments difficult. Nanomaterials, including nanoparticles (NPs) and nanocarriers, offer an array of novel diagnostic and therapeutic applications related to MD. NPs have specific features such as biocompatibility, biochemical stability, targetability, and enhanced visualization using imaging tools. This paper provides a comprehensive and critical review of recent advancements in nanotechnology-based diagnostic and therapeutic approaches for MD. Furthermore, the crucial challenges adversely affecting the use of nanoparticles to treat middle ear disorders are investigated. Finally, this paper provides recommendations and future directions for improving the performances of nanomaterials on theragnostic applications of MD.

Local Delivery of Therapeutics to the Cochlea Using Nanoparticles and Other Biomaterials

Hearing loss negatively impacts the well-being of millions of people worldwide. Systemic delivery of ototherapeutics has limited efficacy due to severe systemic side effects and the presence of the blood-labyrinth barrier that selectively limits or enables transfer of molecules between plasma and inner ear tissues and fluids. Local drug delivery into the middle and inner ear would be preferable for many newly emerging classes of drugs. Although the cochlea is a challenging target for drug delivery, recent technologies could provide a safe and efficacious delivery of ototherapeutics. Local drug delivery routes include topical delivery via the external auditory meatus, retroauricular, transtympanic, and intracochlear delivery. Many new drug delivery systems specifically for the inner ear are under development or undergoing clinical studies. Future studies into these systems may provide a means for extended delivery of drugs to preserve or restore hearing in patients with hearing disorders. This review outlines the anatomy of the (inner) ear, describes the various local delivery systems and routes, and various quantification methodologies to determine the pharmacokinetics of the drugs in the inner ear.

Nanomaterials for Inner Ear Diseases: Challenges, Limitations and Opportunities

The inner ear is located deep in the temporal bone and has a complex anatomy. It is difficult to observe and obtain pathological tissues directly. Therefore, the diagnosis and treatment of inner ear diseases have always been a major clinical problem. The onset of inner ear disease can be accompanied by symptoms such as hearing loss, dizziness and tinnitus, which seriously affect people's lives. Nanoparticles have the characteristics of small size, high bioavailability and strong plasticity. With the development of related research on nanoparticles in inner ear diseases, nanoparticles have gradually become a research hotspot in inner ear diseases. This review briefly summarizes the research progress, opportunities and challenges of the application of nanoparticles in inner ear diseases.

Nanocarriers for Inner Ear Disease Therapy

Hearing loss is a common disease due to sensory loss caused by the diseases in the inner ear. The development of delivery systems for inner ear disease therapy is important to achieve high efficiency and reduce side effects. Currently, traditional drug delivery systems exhibit the potential to be used for inner ear disease therapy, but there are still some drawbacks. As nanotechnology is developing these years, one of the solutions is to develop nanoparticle-based delivery systems for inner ear disease therapy. Various nanoparticles, such as soft material and inorganic-based nanoparticles, have been designed, tested, and showed controlled delivery of drugs, improved targeting property to specific cells, and reduced systemic side effects. In this review, we summarized recent progress in nanocarriers for inner ear disease therapy. This review provides useful information on developing promising nanocarriers for the efficient treatment of inner ear diseases and for further clinical applications for inner ear disease therapy.

Mitochondrial Metabolism Targeted Nanoplatform for Efficient Triple-Negative Breast Cancer Combination Therapy

Tumor reprogram pathway of mitochondrial metabolism is an emerging approach for malignant tumor treatment, such as triple-negative breast cancer. In this study, a tumor/mitochondria cascaded targeting, adenosine-triphosphate (ATP) responsive nanocarrier of zeolitic imidazolate framework-90 (ZIF-90) for breast cancer combination therapy is reported. Atovaquone (AVO) and hemin are loaded into ZIF-90, then a peptide iRGD with tumor-targeting ability is modified on the ZIF-90 nanoplatform. Hemin can specifically degrade BTB and CNC homology1 (BACH1), resulting in the changes of mitochondrial metabolism, and AVO acts as the inhibitor of the electron transport chain (ETC). The degradation of BACH1 using hemin can effectively improve the anti-tumor efficiency of mitochondrial metabolism inhibitor AVO, by increasing dependency on mitochondrial respiration. This nanoplatform displays both tumor-targeting and mitochondria-targeting capacity with high level of ATP responsive drug release behavior. The specific characteristic of mitochondria-targeting ability of this nanoplatform can increase the accumulation of AVO in the mitochondria, and in turn, can effectively improve the inhibition of the ETC. Both in vitro and in vivo results reveal that this composite nanocarrier has excellent tumor inhibition ability with limited side effects. Accordingly, this study provides an attractive strategy in the mitochondrial metabolism for cancer targeted therapy.

Enhancing the Stability of COVID-19 Serological Assay through Metal-Organic Framework Encapsulation

Enzyme-linked immunosorbent assay is widely utilized in serologic assays, including COVID-19, for the detection and quantification of antibodies against SARS-CoV-2. However, due to the limited stability of the diagnostic reagents (e.g., antigens serving as biorecognition elements) and biospecimens, temperature-controlled storage and handling conditions are critical. This limitation among others makes biodiagnostics in resource-limited settings, where refrigeration and electricity are inaccessible or unreliable, particularly challenging. In this work, metal-organic framework encapsulation is demonstrated as a simple and effective method to preserve the conformational epitopes of antigens immobilized on microtiter plate under non-refrigerated storage conditions. It is demonstrated that in situ growth of zeolitic imidazolate framework-90 (ZIF-90) renders excellent stability to surface-bound SARS-CoV-2 antigens, thereby maintaining the assay performance under elevated temperature (40 °C) for up to 4 weeks. As a complementary method, the preservation of plasma samples from COVID-19 patients using ZIF-90 encapsulation is also demonstrated. The energy-efficient approach demonstrated here will not only alleviate the financial burden associated with cold-chain transportation, but also improve the disease surveillance in resource-limited settings with more reliable clinical data.

Noise-Induced Hearing Loss: Updates on Molecular Targets and Potential Interventions

Noise overexposure leads to hair cell loss, synaptic ribbon reduction, and auditory nerve deterioration, resulting in transient or permanent hearing loss depending on the exposure severity. Oxidative stress, inflammation, calcium overload, glutamate excitotoxicity, and energy metabolism disturbance are the main contributors to noise-induced hearing loss (NIHL) up to now. Gene variations are also identified as NIHL related. Glucocorticoid is the only approved medication for NIHL treatment. New pharmaceuticals targeting oxidative stress, inflammation, or noise-induced neuropathy are emerging, highlighted by the nanoparticle-based drug delivery system. Given the complexity of the pathogenesis behind NIHL, deeper and more comprehensive studies still need to be fulfilled.

Rapid modification of antibodies on the surface of liposomes composed of high-affinity protein A-conjugated phospholipid for selective drug delivery

Antibody-modified liposomes, immuno-liposomes, can selectively deliver encapsulated drug ‘cargos’ to cells via the interaction of cell surface proteins with antibodies. However, chemical modification of both the antibodies and phospholipids is required for the preparation of immuno-liposomes for each target protein using conventional methods, which is time-consuming. In the present study, we demonstrated that high-affinity protein A- (Protein A-R28: PAR28) displaying liposomes prepared by the post-insertion of PAR28-conjugated phospholipid through polyethylene glycol (PEG)-linkers (PAR28-PEG-lipo) can undergo rapid modification of antibodies on their surface, and the liposomes can be delivered to cells based on their modified antibodies. Anti-CD147 and anti-CD31 antibodies could be modified with PAR28-PEG-lipo within 1 h, and each liposome was specifically taken up by CD147- and CD31-positive cells, respectively. The cellular amounts of doxorubicin delivered by anti-CD147 antibody-modified PAR28-PEG-lipo were significantly higher than those of isotype control antibody-modified liposomes. PAR28-PEG-lipo can easily and rapidly undergo modification of various antibodies on their surface, which then makes them capable of selective drug delivery dependent on the antibodies.

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PAR28-PEG-lipo underwent rapid modification of antibodies on their surface.

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PAR28-PEG-lipo were modified with various antibodies with Fc regions.

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Antibody-modified PAR28-PEG-lipo were taken up by the targeting cells.

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Antibody-modified PAR28-PEG-lipo delivered DXR into the targeting cells.

Oridonin ameliorates noise-induced hearing loss by blocking NLRP3 - NEK7 mediated inflammasome activation

Inflammation is involved in noise-induced hearing loss (NIHL), but the mechanism is still unknown. The NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome, which triggers the inflammatory cascade, has been implicated in several inflammatory diseases in response to oxidative stress. However, whether the NLRP3 inflammasome is a key factor for permanent NIHL is still unknown. In this study, quantitative real-time polymerase chain reaction (qPCR), western blot, and enzyme-linked immunosorbent assays (ELISAs) demonstrated that the expression levels of activated caspase-1, interleukin (IL)-1β, IL-18, and NLRP3 were significantly increased in the cochleae of mice exposed to broadband noise (120 dB) for 4 h, compared with the control group. These results indicate that the activation of inflammasomes in the cochleae of mice during the pathological process of NIHL as well as NLRP3, a sensor protein of reactive oxygen species (ROS), may be key factors for inflammasome assembly and subsequent inflammation in cochleae. Moreover, many recent studies have revealed that NEK7 is an important component and regulator of NLRP3 inflammasomes by interacting with NLRP3 directly and that these interactions can be interrupted by oridonin. Here, we further determined that treatment with oridonin could indeed interrupt the interaction between NLRP3 and NEK7 as well as inhibit the downstream inflammasome activation in mouse cochleae after noise exposure. Furthermore, we tested anakinra, another inflammatory inhibitor, and it was shown to partially alleviate the degree of hearing impairment in some frequencies in an NIHL mouse model. These discoveries suggest that inhibiting NLRP3 inflammasomes and the downstream signaling pathway may provide a new strategy for the clinical treatment of NIHL.

One-Pot Preparation of Peptide-Doped Metal-Amino Acid Framework for General Encapsulation and Targeted Delivery

Metal-organic frameworks (MOFs), especially those made by biological molecules (bio-MOFs), have been proved to be prospective candidates for biomedical applications. However, a simple and universal bio-MOF to load different substances for precise targeting is still lacking. In this work, we propose a facile one-pot method to prepare a peptide-doped bio-MOF for general encapsulation and targeted delivery. This bio-MOF is constructed by 9-fluorenylmethyloxycarbonyl-modified histidine (Fmoc-His) as a bridging linker that coordinates with Zn2+ ions, denoted as ZFH. The Fmoc-His-Asp-Gly-Arg peptide (Fmoc-HDGR) can be easily doped into the ZFH structure with different ratios to modulate the targeting ability of ZFH-DGR. Containing both hydrophobic Fmoc and hydrophilic His moieties, this framework is compatible with encapsulating various types of payloads, including hydrophobic chemotherapeutic, hydrophilic protein, and positively/negatively charged inorganic nanoparticles. It has also been proved to be highly biocompatible and stable in circulation, exhibit the capabilities to target ανβ3 integrin overexpressed on tumor cells, and trigger drug release in a low pH microenvironment at the tumor site. As a proof of concept, Doxorubicin (Dox)-loaded ZFH-DGR (ZFH-DGR/Dox) demonstrated high cell selectivity between liver hepatocellular carcinoma (HepG2) cells and normal liver (L02) cells, which express high and low ανβ3 integrin, respectively. This selectivity endows ZFH-DGR/Dox precise treatment and low toxicity in Heps-bearing liver cancer mice. This work develops a de novo approach to construct a peptide-doped bio-MOF system for universal load, precise delivery, and peptide drug combination therapy in the future.

Yolk–shell magnetic composite Fe3O4@Co/Zn-ZIF for MR imaging-guided chemotherapy of tumors in vivo

The yolk–shell composites Fe₃O₄@Co/Zn-ZIF exhibited high doxorubicin loading capacity, pH-responsive release characteristics, and strong T₂-weighted MR imaging contrast enhancement, and were used for MR imaging-guided chemotherapy of tumors in vivo.

Microfluidics-Assisted Surface Trifunctionalization of a Zeolitic Imidazolate Framework Nanocarrier for Targeted and Controllable Multitherapies of Tumors

Metal-organic framework (MOF)-based drug delivery nanosystems with both precise drug release and multidrug codelivery capabilities have emerged as promising candidates for cancer treatment. However, challenges are posed by the limited number of suitable payload types, uncontrollable drug leakage, and lack of chemical groups for postmodification. To overcome those challenges, we developed a core-shell nanocomposite composed of zeolitic imidazolate framework-90 (ZIF-90) coated with spermine-modified acetalated dextran (SAD) by a facile microfluidics-based nanoprecipitation method. This nanocomposite could serve as a multidrug storage reservoir for the loading of two drugs with distinct properties, where the hydrophilic doxorubicin (DOX) was coordinately attached to the ZIF-90 framework, and hydrophobic photosensitizer IR780 was loaded into the SAD shell, enabling the combination therapy of photodynamic treatment with chemotherapy. Meanwhile, equipping ZIF-90 with a SAD shell not only substantially improved the pH-responsive drug release of ZIF-90 but also enabled the postformation conjugation of ZIF-90 with hyaluronic acid for specific CD44 recognition, thereby facilitating precise drug delivery to CD44-overexpressed tumor. Such a simple microfluidics-based strategy can efficiently overcome the limitations of solely MOF-based DDSs and greatly extend the flexibility of MOF biomedical applications.