MOF-Based Platform for Kidney Diseases: Advances, Challenges, and Prospects.

Kidney diseases are important diseases that affect human health worldwide. According to the 2020 World Health Organization (WHO) report, kidney diseases have become the top 10 causes of death. Strengthening the prevention, primary diagnosis, and action of kidney-related diseases is of great significance in maintaining human health and improving the quality of life. It is increasingly challenging to address clinical needs with the present technologies for diagnosing and treating renal illness. Fortunately, metal-organic frameworks (MOFs) have shown great promise in the diagnosis and treatment of kidney diseases. This review summarizes the research progress of MOFs in the diagnosis and treatment of renal disease in recent years. Firstly, we introduce the basic structure and properties of MOFs. Secondly, we focus on the utilization of MOFs in the diagnosis and treatment of kidney diseases. In the diagnosis of kidney disease, MOFs are usually designed as biosensors to detect biomarkers related to kidney disease. In the treatment of kidney disease, MOFs can not only be used as an effective adsorbent for uremic toxins during hemodialysis but also as a precise treatment of intelligent drug delivery carriers. They can also be combined with nano-chelation technology to solve the problem of the imbalance of trace elements in kidney disease. Finally, we describe the current challenges and prospects of MOFs in the diagnosis and treatment of kidney diseases.

Current and promising applications of MOF composites in the healing of diabetes wounds.

Diabetes mellitus is an exponentially growing chronic metabolic disease identified by prolonged hyperglycemia that leads to a plethora of health problems. It is well established that the skin of diabetic patients is more prone to injury, and hence, wound healing is an utmost critical restorative process for injured skin and other tissues. Diabetes patients have problems with wound healing at all stages, which ultimately results in delays in the healing process. Therefore, it is vital to find new medications or techniques to hasten the healing of wounds. Metal-organic frameworks (MOFs), an assorted class of porous hybrid materials comprising metal ions coordinated to organic ligands, can display great potential in accelerating diabetic wound healing due to their good physicochemical properties. The release of metal ions during the degradation of MOFs can promote the differentiation of fibroblasts into myofibroblasts and subsequently angiogenesis. Secondly, similar to enzyme-like active substances, they can eliminate reactive oxygen species (ROS) overproduction (secondary to the bio-load of wound bacteria), which is conducive to accelerating diabetic wound healing. Subsequently, MOFs can support the slow release of drugs (molecular or gas therapeutics) in diabetic wounds and promote wound healing by regulating pathological signaling pathways in the wound microenvironment or inhibiting the expression of inflammatory factors. In addition, the combination of photodynamic and photothermal therapies using photo-stimulated porphyrin-based MOF nanosystems has brought up a new idea for treating complicated diabetic wound microenvironments. In this review, recent advances affecting diabetic wound healing, current means of rapid diabetic wound healing, and the limitations of traditional approaches are discussed. Further, the diabetic wound healing applications of MOFs have been discussed followed by the future challenges and directions of MOF materials in diabetic wound healing.

Advances in drug delivery-based therapeutic strategies for renal fibrosis treatment.

Renal fibrosis is the result of all chronic kidney diseases and is becoming a major global health hazard. Currently, traditional treatments for renal fibrosis are difficult to meet clinical needs due to shortcomings such as poor efficacy or highly toxic side effects. Therefore, therapeutic strategies that target the kidneys are needed to overcome these shortcomings. Drug delivery can be attained by improving drug stability and addressing controlled release and targeted delivery of drugs in the delivery category. By combining drug delivery technology with nanosystems, controlled drug release and biodistribution can be achieved, enhancing therapeutic efficacy and reducing toxic cross-wise effects. This review discusses nanomaterial drug delivery strategies reported in recent years. Firstly, the present review describes the mechanisms of renal fibrosis and anti-renal fibrosis drug delivery. Secondly, different nanomaterial drug delivery strategies for the treatment of renal injury and fibrosis are highlighted. Finally, the limitations of these strategies are also discussed. Investigating various anti-renal fibrosis drug delivery strategies reveals the characteristics and therapeutic effects of various novel nanosystem-derived drug delivery approaches. This will serve as a reference for future research on drug delivery strategies for renal fibrosis treatment.

[The enhancement of electric field distribution in one-dimensional metallic-dielectric photonic crystals].

The authors theoretically study the transmission properties and electric filed distribution in one-dimensional metallic-dielectric photonic crystals with the transfer matrix method. The results show that the physical properties can be improved considerably after the introduction of antireflection layer and optimizing structural parameters, e. g., 77% electric file distribution in metal layers can be obtained under 19% transmittance, and 72% transmittance can be obtained with 28% electric field distribution in metal layers. These photonic crystal structures, whose transmission properties and electric field in metal layers are tunable, could be widely used in nonlinear photon device based on the enhancement of electric field in metal layers.

[Spectral properties of two-dimensional photonic crystal quantum well structures].

In the present paper, the spectral properties of two-dimensional (2D) photonic crystal quantum well structures were studied numerically. The structures consist of a 2D photonic crystal (PC) with square lattice of parallel dielectric circular columns in air and some middle layers of columns are removed. Similar to the electrons in semiconductor quantum wells, the photonic bandgap (PBG) in PC can act as a potential barrier to photons, which gives rise to quantized photonic states in the PBG region. Photonic band structures were calculated using plane wave expansion method and transmission spectra were obtained using transfer matrix method. The results show that discrete transmission peaks appear in PBG region. More transmission peaks arise with the increase of the well layer and the strength decreases with the increase in the potential layer width. The relationships between the frequency of transmission peaks and the width of well layer were also discussed.

[Optical properties of one-dimensional metallodielectric photonic crystals].

The optical characteristics of one-dimensional metallodielectric photonic crystals (MDPC), constructed by inserting metal aluminum layers of certain thickness into the Si/SiO2 system, were studied theoretically with the transfer matrix method. The results show that the reflection efficiency can be enhanced considerably after the introduction of metallic layers, e. g. the rejection level of each period increased from 7.2 dB([Si(46 nm)/SiO2 (120 nm)]5) to 20 dB ([Si(46 nm)/SiO2 (60 nm)/Al (10 nm)/SiO2 (60 nm)]5). In addition, high omnidirectional reflection band with broader width can be obtained, e. g. bandwidth of 550 nm can be offered with [Si(46 nm)/SiO2 (60 nm)/Al (30 nm)/SiO2 (60 nm)]5. Rules of how the absorption, thickness and position of the metal layers affect the optical characteristics of the MDPC are also discussed. These MDPC structures may be used as compact-size, low-loss and broad-band optical reflectors.