Chirality-driven strong thioredoxin reductase inhibition

Overexpression of thioredoxin reductase (TXNRD) plays crucial role in tumorigenesis. Therefore, designing TXNRD inhibitors is a promising strategy for targeted anticancer drug development. However, poor selectivity has always been a challenge, resulting in unavoidable toxicity in clinic. Herein we demonstrate a strategy to develop highly selective chiral metal complexes-based TXNRD inhibitors. By manipulating the conformation of two distinct weakly interacting groups, we optimize the compatibility between the drug and the electrophilic group within the active site of TXNRD to enhance their non-covalent interaction, thus effectively avoids the poor selectivity deriving from covalent drug interaction, on the basis of ensuring the strong inhibition. Detailed experimental and computational results demonstrate that the chiral isomeric drugs bind to the active site of TXNRD, and the interaction strength is well modulated by chirality. Especially, the meso-configuration, in which the two large sterically hindered active groups are positioned on opposite sides of the drug, exhibits the highest number of non-covalent interactions and most effective inhibition on TXNRD. Taken together, this work not only provides a novel approach for developing highly selective proteinase inhibitors, but also sheds light on possible underlying mechanisms for future application.

Biosynthesis of fungus-based oral selenium microcarriers for radioprotection and immuno-homeostasis shaping against radiation-induced heart disease

Radiation-induced heart disease (RIHD), characterized by severe oxidative stress and immune dysregulation, is a serious condition affecting cancer patients undergoing thoracic radiation. Unfortunately, clinical interventions for RIHD are lacking. Selenium (Se) is a trace element with excellent antioxidant and immune-modulatory properties. However, its application in heart radioprotection remains challenging. Herein, we developed a novel bioactive Cordyceps militaris-based Se oral delivery system (Se@CM), which demonstrated superior radioprotection effects in vitro against X-ray-induced damage in H9C2 cells through suppressing excessive ROS generation, compared to the radioprotectant Amifostine. Moreover, Se@CM exhibited exceptional cardioprotective effects in vivo against X-ray irradiation, reducing cardiac dysfunction and myocardial fibrosis by balancing the redox equilibrium and modulating the expression of Mn-SOD and MDA. Additionally, Se@CM maintained immuno-homeostasis, as evidenced by the upregulated population of T cells and M2 macrophages through modulation of selenoprotein expression after irradiation. Together, these results highlight the remarkable antioxidant and immunity modulation properties of Se@CM and shed light on its promising application for cardiac protection against IR-induced disease. This research provides valuable insights into developing effective strategies for preventing and managing RIHD.

Recent Advances of Seed-Mediated Growth of Metal Nanoparticles: from Growth to Applications

Unprecedented advances in metal nanoparticle synthesis have paved the way for broad applications in sensing, imaging, catalysis, diagnosis, and therapy by tuning the optical properties, enhancing catalytic performance, and improving chemical and biological properties of metal nanoparticles. The central guiding concept for regulating the size and morphology of metal nanoparticles is identified as the precise manipulation of nucleation and subsequent growth, often known as seed-mediated growth methods. However, since the growth process is sensitive not only to the metal seeds but also to capping agents, metal precursors, growth solution, growth/incubation time, reductants, and other influencing factors, the precise control of metal nanoparticle morphology is multifactorial. Further, multiple reaction parameters are entangled with each other, so it is necessary to clarify the mechanism by which each factor precisely regulates the morphology of metal nanoparticles. In this review, to exploit the generality and extendibility of metal nanoparticle synthesis, the mechanisms of growth influencing factors in seed-mediated growth methods are systematically summarized. Second, a variety of critical properties and applications enabled by grown metal nanoparticles are focused upon. Finally, the current progress and offer insights on the challenges, opportunities, and future directions for the growth and applications of grown metal nanoparticles are reviewed.

Chirality-enhanced transport and drug delivery of graphene nanocarriers to tumor-like cellular spheroid

Chirality, defined as "a mirror image," is a universal geometry of biological and nonbiological forms of matter. This geometry of molecules determines how they interact during their assembly and transport. With the development of nanotechnology, many nanoparticles with chiral geometry or chiroptical activity have emerged for biomedical research. The mechanisms by which chirality originates and the corresponding synthesis methods have been discussed and developed in the past decade. Inspired by the chiral selectivity in life, a comprehensive and in-depth study of interactions between chiral nanomaterials and biological systems has far-reaching significance in biomedicine. Here, we investigated the effect of the chirality of nanoscale drug carriers, graphene quantum dots (GQDs), on their transport in tumor-like cellular spheroids. Chirality of GQDs (L/D-GQDs) was achieved by the surface modification of GQDs with L/D-cysteines. As an in-vitro tissue model for drug testing, cellular spheroids were derived from a human hepatoma cell line (i.e., HepG2 cells) using the Hanging-drop method. Our results reveal that the L-GQDs had a 1.7-fold higher apparent diffusion coefficient than the D-GQDs, indicating that the L-GQDs can enhance their transport into tumor-like cellular spheroids. Moreover, when loaded with a common chemotherapy drug, Doxorubicin (DOX), via π-π stacking, L-GQDs are more effective as nanocarriers for drug delivery into solid tumor-like tissue, resulting in 25% higher efficacy for cancerous cellular spheroids than free DOX. Overall, our studies indicated that the chirality of nanocarriers is essential for the design of drug delivery vehicles to enhance the transport of drugs in a cancerous tumor.

Amelioration Strategies for Silver Diamine Fluoride: Moving from Black to White

Topical cariostatic agents have become a reasonable alternative for managing dental caries in young children. Silver diamine fluoride (SDF) is a practical topical approach to arrest caries and avoid extensive and risky dental treatment. However, the literature demonstrates a parental hesitation towards accepting SDF because of black unaesthetic tooth discolouration following application. The rapid oxidation of ionic silver darkens demineralised tooth structure permanently. In this regard, nano-metallic antimicrobials could augment or substitute for silver, and thereby enhance SDF aesthetic performance. Recently, biomedical research has drawn attention to selenium nanoparticles (SeNPs) due to their antimicrobial, antioxidant, and antiviral potencies. Various in vitro studies have examined the effect of SeNPs on the virulence of bacteria. This narrative review explores practical issues when using SDF and suggests future directions to develop it, focusing on antimicrobial metals. Several methods are described that could be followed to reduce the discolouration concern, including the use of nanoparticles of silver, of silver fluoride, or of selenium or other metals with antimicrobial actions. There could also be value in using remineralising agents other than fluoride, such as NPs of hydroxyapatite. There could be variations made to formulations in order to lower the levels of silver and fluoride in the SDF or even to replace one or both of the silver and fluoride components completely. Moreover, since oxidation processes appear central to the chemistry of the staining, adding SeNPs which have antioxidant actions could have an anti-staining benefit; SeNPs could be used for their antimicrobial actions as well. Future research should address the topic of selenium chemistry to optimise how SeNPs would be used with or in place of ionic silver. Incorporating other antimicrobial metals as nanoparticles should also be explored, taking into account the optimal physicochemical parameters for each of these.

Mycosynthesis of highly fluorescent selenium nanoparticles from Fusarium oxysporum, their antifungal activity against black fungus Aspergillus niger, and in-vivo biodistribution studies

In the past few years, photo-luminescent inorganic materials have been studied extensively as fluorescent sensors, and diagnostic and bioimaging tools. The assessment of photoluminescence (PL) properties of selenium nanoparticles (Se NPs), especially mycosynthesized Se NPs, is still in its infancy. Herein, we have biosynthesized highly dispersed fluorescent Se NPs (42 nm) using endophytic fungus Fusarium oxysporum, and fully characterized them using sophisticated instruments like TEM, XRD, UV–Vis spectrophotometer, FTIR, and PL spectrometer. To determine the therapeutic efficacy and side effect profiles, these crystalline Se NPs were radiolabeled with technetium-99m (^99mTc) and their biodistribution and renal clearance times were investigated in the normal Wister rat. The results showed that these Se NPs may be useful for targeting the lungs and liver dysfunction as significant accumulation of these NPs was observed in the liver (approx. 19.47 ± 4%) and lungs (at 6 ± 1%) after 10 min of post-injection. Quick circulation and the presence of Se NPs in kidney (3.8 ± 2%) also suggested the easy excretion of these NPs from the body through urinary tract. Furthermore, the antioxidant activity of Se NPs (IC₅₀, 159.5 μg/mL) has been investigated using DPPH free radical scavenging assay with scavenging efficacy of 80.4% where ascorbic acid (IC₅₀, 5.6 μg/mL) was used as a positive control. Additionally, the microscopic study of the inhibition zone encircled around Se NPs confirmed their strong antifungal and antisporulant activity against the black fungus Aspergillus niger.

Improved Photodynamic Activity of Phthalocyanine by Adjusting the Chirality of Modified Amino Acids

Herein, four zinc phthalocyanines (ZnPcs) with chiral lysine modification were synthesized. We found that the chirality of lysine and the chiral structure position strongly influence the properties of ZnPcs. Among the four ZnPcs, d-lysine-modified ZnPc through -NH₂ on C_ε [denoted N(ε)-d-lys-ZnPc] showed superior properties, including tumor enrichment, cancer cell uptake, and tumor retention capability, compared to the other three ZnPcs. Thus, chiral molecule modification is a simple and effective strategy to regulate the abovementioned properties to achieve a satisfactory antitumor outcome of drugs.

Reversing the Chirality of Surface Ligands Can Improve the Biosafety and Pharmacokinetics of Cationic Gold Nanoclusters

Severe toxicity and rapid in vivo clearance of cationic nanomaterials seriously hinder their clinical translation. Present strategies to improve the biosafety and in vivo performance of cationic nanomaterials require neutralization of positive charge, which often compromises their efficacy. Herein, we report that substituting L-glutathione (L-GSH) on cationic gold nanoclusters (GNCs) with its D-counterpart can effectively improve the biosafety and pharmacokinetics. Compared with L-GNCs, D-GNCs do not exhibit cellular cytotoxicity, hemolysis, or acute damage to organs. Cationic D-GNCs show less cell internalization than L-GNCs, and do not induce cellular apoptosis. In vivo, the chirality of surface ligands distinctly affects the pharmacokinetics and tumor targeting abilities of D-/L-GNCs. D-GNCs show higher extended circulation time in blood plasma compared to similarly-sized and poly (ethylene glycol)-modified gold nanoparticles. This work demonstrates that the choice of chirality of surface ligands can determine toxicities and pharmacokinetics of cationic nanomaterials.

Near-infrared laser-triggered drug release in a tellurium nanosystem for simultaneous chemo-photothermal cancer therapy

Tumor cells can be selectively killed by heat application based on the different tolerances of normal cells and tumor cells to temperature. However, the limited clinical application of photothermal therapy (PTT) is mainly due to various practical implementation difficulties, of which the most important is how to fully heat the tumor. The combination of PTT and chemotherapy can synergistically enhance cell membrane permeability and reduce the dose of chemotherapy drugs to not only effectively kill the tumor but also reduce the damage to normal tissues. It is of great significance to develop materials that can be simultaneously used for tumor PTT and chemotherapy. Therefore, in this study, a functionalized tellurium (Te) nanosystem (DOX/PEI@TeNPs) was prepared to achieve chemo-photothermal cancer combination therapy. Our research showed that the DOX/PEI@TeNP morphology was controllable, and it had good photothermal conversion efficiency and light stability. Moreover, DOX/PEI@TeNPs containing doxorubicin (DOX) showed almost no drug release in normal tissues and neutral-pH environments, while in tumor cells and tissues, it massively released DOX to kill cancer cells. The as-synthesized DOX/PEI@TeNP system can produce reactive oxygen species (ROS) under near-infrared (NIR) light irradiation and features a high photothermal conversion efficiency due to its strong NIR absorbance. Therefore, this study provides an effective strategy for the effective design of nano-drugs, which can be used for the accurate chemical-photothermal synergistic therapy of tumors.

Synthesis of Double Interfering Biodegradable Nano-MgO Micelle Composites and Their Effect on Parkinson's Disease

Although gene therapy targeting the α-synuclein gene (SNCA) has achieved outstanding results in the treatment of Parkinson's disease (PD), the lack of a suitable gene delivery system and inadequate therapeutic effects remains a tremendous obstacle for RNAi therapy. Here, a degradable nano-MgO micelle composite (MgO(pDNA)-INS-Plu-mRNA-NGF) with double interference (mediated by RNAi and α-synuclein (α-syn)-targeted mRNA) was constructed. Binding mRNA treatment significantly increased the inhibitory effect compared to the reduction of α-syn expression by RNAi alone. Moreover, the cell experiments demonstrated that the viability of the PD cell model can be significantly improved by nano-MgO micelle composite treatment. More importantly, the composite has the ability to penetrate the blood brain barrier and deliver genes and mRNA to neurons through endocytosis mediated by the nerve growth factor and its receptors, thus significantly downregulating the expression of α-syn in the PD mice model without causing damage to other major organs. Overall, this work provides a novel insight into the design of biomaterials for gene therapy for PD.

Coordination-Driven Enhancement of Radiosensitization by Black Phosphorus via Regulating Tumor Metabolism

Coordination-driven surface modification is an effective strategy to achieve nanosystem functionalization and improved physicochemical performance. Black phosphorus (BP)-based nanomaterials demonstrate great potential in cancer therapy, but their poor stability, low X-ray mass attenuation coefficient, and nonselectivity limit the application in radiotherapy. Herein, we used unsaturated iridium complex to coordinate with BP nanosheets to synthesize a two-dimensional layered nanosystem (RGD-Ir@BP) with higher biostability. Ir complex improves the photoelectric properties and photoinduced charge carrier dynamics of BP, hence Ir@BP generated more singlet oxygen after X-ray irradiation. In in vivo experiments, with X-ray irradiation, RGD-Ir@BP effectively inhibited nasopharyngeal carcinoma tumor growth but with minor side effects. Additionally, based on untargeted metabolomics analysis, the combined treatment specifically down-regulated the tumor proliferative mark of prostaglandin E2 in cancer cells. In general, this study provides a design strategy of high-performance coordination-driven BP-based nanosensitizer in cancer radiotherapy.

Biomedical Application of Reactive Oxygen Species-Responsive Nanocarriers in Cancer, Inflammation, and Neurodegenerative Diseases

Numerous pathological conditions, including cancer, inflammatory diseases, and neurodegenerative diseases, are accompanied by overproduction of reactive oxygen species (ROS). This makes ROS vital flagging molecules in disease pathology. ROS-responsive drug delivery platforms have been developed. Nanotechnology has been broadly applied in the field of biomedicine leading to the progress of ROS-responsive nanoparticles. In this review, we focused on the production and physiological/pathophysiological impact of ROS. Particular emphasis is put on the mechanisms and effects of abnormal ROS levels on oxidative stress diseases, including cancer, inflammatory disease, and neurodegenerative diseases. Finally, we summarized the potential biomedical applications of ROS-responsive nanocarriers in these oxidative stress diseases. We provide insights that will help in the designing of new ROS-responsive nanocarriers for various applications.

Smart Microenvironment-Responsive Organocopper(II) Supramolecular Polymers to Regulate the Stability and Anticancer Efficacy by Different Substituents

The search for chemotherapeutic drugs with a high efficiency and low toxicity continues to be a challenge in tumor treatment for scientists. Organometallic supramolecular polymers are an attractive option to achieve this goal, not only due to the fact that they possess both advantages of metal complexes and nanostructures but also because they are usually sensitive to pH. Here, we report the design and synthesis of a series novel smart microenvironment-responsive organocopper(II) supramolecular polymers with various substituted ligands to regulate their stability and anticancer efficacy. The investigation of the possible mechanisms revealed that the organocopper(II) polymers enter cancer cells through endocytosis and then induce apoptosis of cancer cells. Furthermore, the in vivo anticancer efficacy study demonstrated that these organocopper(II) polymers inhibited the tumor growth effectively without damage to the major organs. Overall, the organocopper(II) supramolecular polymers present a promising pathway to achieve high-efficiency and low-toxicity chemotherapy.

Adjusting the lipid-water distribution coefficient of iridium(III) complexes to enhance the cellular penetration and treatment efficacy to antagonize cisplatin resistance in cervical cancer

The effective design of metal complexes to manipulate their lipid-water distribution coefficient is an appealing strategy for improving their cellular penetration and treatment efficacy. Here, we conveniently synthesized three iridium (Ir) complexes with red fluorescence via the simple non-conjugate modification of the side arm of the ligand. Bio-evaluation revealed that upon adding non-conjugate selenium (Se) arene derivatives, the lipid-water distribution coefficient of Ir-Se was found to be suitable, not only decreasing the toxic side effects of complexes to normal cells, but also effectively improving their anticancer activity via enhancing their penetration into tumor cells. Moreover, mechanistic investigations demonstrated that Ir-Se entered R-HeLa cells through endocytosis, and triggered apoptosis via the down-regulation of the mitochondrial membrane potential and excessive production of singlet oxygen, thereby possessing a highly effective cytotoxicity to antagonize cisplatin resistance. Therefore, we developed a convenient strategy to derive functional metal complexes and revealed that the introduction of Se on the side arm of the ligand provided the complexes with the capacity to reverse multidrug resistance.