Synthesis of Chiral Carbo-Nanotweezers for Enantiospecific Recognition and DNA Duplex Winding in Cancer Cells

In situ carbonization metamorphoses porous silica particles into biodegradable therapeutic carriers of lesser consequence on TGF-β1 mediated fibrosis

Extensive modifications have been made to the synthesis protocol for porous silica particles to improve the shape, size and yield percentage, but problems associated with improvement in biodegradability and decrease in chances to induce side effects still remain a concern. To circumvent these limitations, a facile modification strategy has been employed through in situ carbonization of porous silica particles. Herein, carbon particles were integrated within porous silica core-shell particles (Si-P-CNPs) during the synthesis process and found to preserve the ordered structural morphology. Curcumin was used as a model drug for loading in prepared Si-P-CNPs whereas lung cancer cells were used as a model system to study the in vitro fate. These Si-P-CNPs showed improved drug loading, drug effectivity, biodegradability and avoidance of interaction with transforming growth factor β1 (TGF-β1) indicating the possibility of reducing the chances of lung fibrosis and thereby enhancing the safety profile over conventional porous silica particles.

Advances in Enantiomer-Dependent Nanotherapeutics

The nanoscale properties of nanomaterials, especially nanoparticles, including size, shape, and surface charge, have been extensively studied for their impact on nanomedicine. Given the inherent chiral nature of biological systems and their high enantiomeric selectivity, there is rising interest to manipulate the chirality of nanomaterials to enhance their biomolecular interactions and improve nanotherapeutics. Chiral nanostructures are currently more prevalently used in biosensing and diagnostic applications owing to their distinctive physical and optical properties, but they hold great promise for use in nanomedicine. In this Review, we first discuss stereospecific interactions between chiral nanomaterials and biomolecules before comparing the synthesis and characterization methods of chiral nanoparticles and nanoassemblies. Finally, we examine the applications of chiral nanotherapeutics in cancer, immunomodulation, and neurodegenerative diseases and propose plausible mechanisms in which chiral nanomaterials interact with cells for biological manipulation. This Review on chirality is a timely reminder of the arsenal of nanoscale modifications to boost research in nanotherapeutics.

A narrative review on the role of carbon nanoparticles in oncology

The lymphatic system is the first site of metastasis for most tumors and is a common reason for the failure of cancer therapy. The lymphatic system's anatomical properties make it difficult to deliver chemotherapy agents at therapeutic concentrations while avoiding systemic toxicity. Carbon nanoparticles offer a promising alternative for identifying and transporting therapeutic molecules. The larger diameter of lymphatic vessels compared to the diameter of blood vessels, allows carbon nanoparticles to selectively enter the lymphatic system once administered subcutaneously. Carbon nanoparticles stain tumor-draining lymph nodes black following intratumoral injection, making them useful in sentinel lymph node mapping. Drug-loaded carbon nanoparticles allow higher concentrations of chemotherapeutics to accumulate in regional lymph nodes while decreasing plasma drug accumulation. The use of carbon nanoparticles for chemotherapy delivery has been associated with lower mortality, fewer histopathology changes in vital organs, and lower serum concentrations of hepatocellular enzymes. This review will focus on the ability of carbon nanoparticles to target the lymphatics as well as their current and potential applications in sentinel lymph node mapping and oncology treatment regimens. This article is categorized under: Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery.

Nanoparticles and Nanomaterials-Based Recent Approaches in Upgraded Targeting and Management of Cancer: A Review

Along with the extensive improvement in tumor biology research and different therapeutic developments, cancer remains a dominant and deadly disease. Tumor heterogeneity, systemic toxicities, and drug resistance are major hurdles in cancer therapy. Chemotherapy, radiotherapy, phototherapy, and surgical therapy are some prominent areas of cancer treatment. During chemotherapy for cancer, chemotherapeutic agents are distributed all over the body and also damage normal cells. With advancements in nanotechnology, nanoparticles utilized in all major areas of cancer therapy offer the probability to advance drug solubility, and stability, extend drug half-lives in plasma, reduce off-target effects, and quintessence drugs at a target site. The present review compiles the use of different types of nanoparticles in frequently and recently applied therapeutics of cancer therapy. A recent area of cancer treatment includes cancer stem cell therapy, DNA/RNA-based immunomodulation therapy, alteration of the microenvironment, and cell membrane-mediated biomimetic approach. Biocompatibility and bioaccumulation of nanoparticles is the major impediment in nano-based therapy. More research is required to develop the next generation of nanotherapeutics with the incorporation of new molecular entities, such as kinase inhibitors, siRNA, mRNA, and gene editing. We assume that nanotherapeutics will dramatically improve patient survival, move the model of cancer treatment, and develop certainty in the foreseeable future.

Tröger's Base Chemistry in Solution and in Zr(IV)-Based Metal-Organic Frameworks

Tröger's base (TB) and its derivatives have been studied extensively due to their unique concave shape stemming from the endomethylene strap. However, the strap-clipped TB chemistry has been largely overlooked in metal-organic framework (MOF) solids, leading to a gap in our knowledge within this field. In this work, we report the in situ strap elimination of a carboxylate-carrying TB in the presence of formic acid, both in solution and in Zr(IV)-based MOFs. In the solution system, the methanodiazocine nucleus can be exclusively transformed into an N,N'-diformyl-decorated phenhomazine derivative, regardless of the solvent used (DMF, DMA, or DEF), as unambiguously uncovered by single crystal X-ray crystallography. In contrast, while in the MOF synthetic system, the degree of derivatization reaction can be effectively controlled to give either the secondary diamine or formyl-decorated diamine, depending on the solvent used (DMF or DEF), resulting in the formation of two Zr-MOFs with 8-connected bcu (NU-1900) and 12-connected fcu (NU-407) topologies, respectively. The derivatization mechanism is proposed to be topology-guided and dependent on the local acid concentration during the MOF formation processes. Moreover, we discovered a novel post-synthetically water-induced in situ linker formylation process in NU-1900 through sequential formic acid elimination, migration, and condensation processes, affording an isostructural framework with the same linker as in NU-407, which further corroborates our proposed mechanism. Additionally, the highly defective NU-1900 with abundant accessible Zr sites was demonstrated to be an outstanding catalyst for the detoxification of a nerve agent simulant with a half-life of less than 1 min.

Chiral FA Conjugated CdTe/CdS Quantum Dots for Selective Cancer Ablation

Inducing apoptosis in cancer cells is considered a potential therapeutic mechanism underlying cancers. Here, chiral folic acid (FA) conjugated Cys-CdTe/CdS quantum dots (QDs) conjugated with a cancer-targeting ligand were fabricated to induce apoptosis in vivo. Ligand-induced chirality mechanism for FA-Cys-CdTe/CdS QDs was discussed, which is verified by density functional theory (DFT) simulation. Interestingly, we found that the circular dichroism (CD) signals of chiral QDs can effectively distinguish breast cancer cells from normal cells, where a sharp decrease in CD signal and absorption intensity can be seen. Notably, chiral FA-Cys-CdTe/CdS QDs showed significant apoptosis-inducing ability after the release of mitochondrial apoptotic factors. Furthermore, in vivo experiments showed that chiral FA-Cys-CdTe/CdS QDs provide an efficient cancer ablation through the apoptosis process with negligible toxicity, demonstrating their great potential utility in targeted anticancer agent for future clinic application.

Chiral nanomaterials for tumor therapy: autophagy, apoptosis, and photothermal ablation

Chirality is a fundamental characteristic of natural molecules and a crucial factor in the biochemical reactions of living cells and organisms. Recently, researchers have successfully introduced chiral molecules to the surfaces of nanomaterials, creating chiral nanomaterials that exhibit an upscaling of chiral behavior from the molecular scale to the nanoscale. These chiral nanomaterials can selectively induce autophagy, apoptosis, and photothermal ablation in tumor cells based on their chirality, making them promising for application in anti-tumor therapy. However, these interesting and important phenomena have hitherto received little attention. Accordingly, we herein present a review of recent research progress in the field of chiral nanomaterials for tumor therapy along with brief looks at the mechanistic details of their actions. Finally, the current challenges and future perspectives of chiral nanomaterials in terms of maximizing their potential in tumor therapy are discussed. Thus, this review provides a helpful introduction to the design of chiral nanomaterials and will hopefully highlight the importance of chirality in tumor therapy.

DNA-cleavage activity of the iron(II) complex with optically active ligands, meta- and para-xylyl-linked N',N'-dipyridylmethyl-cyclohexane-1,2-diamine

DNA-cleavage agents such as bleomycin have potential anticancer applications. The development of a DNA-cleavage reagent that recognizes specific sequences allows the development of cancer therapy with reduced side effects. In this study, to develop novel compounds with specific DNA-cleavage activities, we synthesized optically active binuclear ligands, (1R,1'R,2R,2'R)-N¹,N^1'-(meta/para-phenylenebis(methylene))bis(N²,N²-bis(pyridin-2-ylmethyl)cyclohexane-1,2-diamine) and their enantiomers. The DNA-cleavage activities of these compounds were investigated in the presence of Fe(II)SO₄ and sodium ascorbate. The obtained results indicated that the Fe(II) complexes of those compounds efficiently cleave DNA and that their cleavage was subtle sequence-selective. Therefore, we succeeded in developing compounds that can be used as small-molecule drugs for cancer chemotherapy.

Design and synthesis of an anthranyl bridged optically active dinuclear iron(II)-ligand and evaluation of DNA-cleaving activity

It is necessary to design a ligand that is compatible with the target molecule to optimally use the DNA-cleaving ability of metal complexes. In this study, we synthesized an optically active dinuclear ligand, (1R,1'R,2R,2'R)-N¹,N^1'-(anthracene-1,8-diylbis(methylene))bis(N²,N²-bis(pyridin-2-ylmethyl)cyclohexane-1,2-diamine) (R-ABDC, 4a) and its enantiomer (S-ABDC, 4b). We then prepared their Fe(II) complexes by mixing the ligand with FeSO₄·7H₂O in situ and investigated DNA-cleaving activities using plasmid DNA in the presence of excess sodium ascorbate at atmospheric conditions. The Fe(II) complexes efficiently cleaved DNA and selectively recognized two consecutive A and/or T sequences.

Enzyme-catalysed biodegradation of carbon dots follows sequential oxidation in a time dependent manner

Carbon dots (CDs) have recently garnered significant attention owing to their excellent luminescence properties, thereby demonstrating a variety of applications in in vitro and in vivo imaging. Understanding the long-term metabolic fate of these agents in a biological environment is the focus of this work. Here we show that the CDs undergo peroxide catalysed degradation in the presence of lipase. Our results indicate that differently charged CD species exhibit unique degradation kinetics upon being subjected to enzyme oxidation. Furthermore, this decomposition correlates with the relative accessibility of the enzymatic molecule. Using multiple physico-chemical characterization studies and molecular modelling, we confirmed the interaction of passivating surface abundant molecules with the enzyme. Finally, we have identified hydroxymethyl furfural as a metabolic by-product of the CDs used here. Our results indicate the possibility and a likely mechanism for complete CD degradation in living systems that can pave the way for a variety of biomedical applications.