Unleashing the Potential of Camptothecin: Exploring Innovative Strategies for Structural Modification and Therapeutic Advancements

Camptothecin (CPT) is a potent anti-cancer agent targeting topoisomerase I (TOP1). However, CPT has poor pharmacokinetic properties, causes toxicities, and leads to drug resistance, which limit its clinical use. In this paper, to review the current state of CPT research. We first briefly explain CPT's TOP1 inhibition mechanism and the key hurdles in CPT drug development. Then we examine strategies to overcome CPT's limitations through structural modifications and advanced delivery systems. Though modifications alone seem insufficient to fully enhance CPT's therapeutic potential, structure-activity relationship analysis provides insights to guide optimization of CPT analogs. In comparison, advanced delivery systems integrating controlled release, imaging capabilities, and combination therapies via stimulus-responsive linkers and targeting moieties show great promise for improving CPT's pharmacological profile. Looking forward, multifaceted approaches combining selective CPT derivatives with advanced delivery systems, informed by emerging biological insights, hold promise for fully unleashing CPT's anti-cancer potential.

Smart Targeted Delivery Systems for Enhancing Antitumor Therapy of Active Ingredients in Traditional Chinese Medicine

As a therapeutic tool inherited for thousands of years, traditional Chinese medicine (TCM) exhibits superiority in tumor therapy. The antitumor active components of TCM not only have multi-target treatment modes but can also synergistically interfere with tumor growth compared to traditional chemotherapeutics. However, most antitumor active components of TCM have the characteristics of poor solubility, high toxicity, and side effects, which are often limited in clinical application. In recent years, delivering the antitumor active components of TCM by nanosystems has been a promising field. The advantages of nano-delivery systems include improved water solubility, targeting efficiency, enhanced stability in vivo, and controlled release drugs, which can achieve higher drug-delivery efficiency and bioavailability. According to the method of drug loading on nanocarriers, nano-delivery systems can be categorized into two types, including physically encapsulated nanoplatforms and chemically coupled drug-delivery platforms. In this review, two nano-delivery approaches are considered, namely physical encapsulation and chemical coupling, both commonly used to deliver antitumor active components of TCM, and we summarized the advantages and limitations of different types of nano-delivery systems. Meanwhile, the clinical applications and potential toxicity of nano-delivery systems and the future development and challenges of these nano-delivery systems are also discussed, aiming to lay the foundation for the development and practical application of nano-delivery systems of TCM in clinical settings.

Sonodynamic Therapy Using Dacarbazine-Loaded AuSiO2 Nanoparticles for Melanoma Treatment: An In-Vitro Study on the B16F10 Murine Melanoma Cell Line

The use of nanoparticles as a sonosensitizer in cancer sonodynamic therapy has been gaining attention because of their great advantages in drug delivery applications. By conjugating chemotherapy agents with nanoparticles, we can develop a drug delivery platform, control drug release and improve the outcome of treatments. The in-vitro study described here evaluates the combination of AuSiO₂ nanoparticles and dacarbazine (DTIC@AuSiO₂) as a sonosensitizer for sonodynamic therapy of melanoma. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays revealed that the viability of B16F10 melanoma cells was significantly inhibited by the increase in apoptosis induction in treatment with DTIC@AuSiO₂ nanoparticles under ultrasound exposure compared with treatment with the free DTIC or AuSiO₂ nanoparticles. The sonosensitization activity of AuSiO₂ nanoparticles and greater uptake of DTIC by tumor cells after loading in DTIC@AuSiO₂ nanoparticles inhibited the proliferation of melanoma tumor cells effectively. In conclusion, the DTIC@AuSiO₂ nanoparticles established in this study could represent a good drug delivery and sonosensitizer platform for use in melanoma sonodynamic therapy.

ZnO nanostructured materials and their potential applications: progress, challenges and perspectives

Extensive research in nanotechnology has been conducted to investigate new behaviours and properties of materials with nanoscale dimensions. ZnO NPs owing to their distinct physical and chemical properties have gained considerable importance and are hence investigated to a detailed degree for exploitation of these properties. This communication, at the outset, elaborates the various chemical methods of preparation of ZnO NPs, viz., the mechanochemical process, controlled precipitation, sol-gel method, vapour transport method, solvothermal and hydrothermal methods, and methods using emulsion and micro-emulsion environments. The paper further describes the green methods employing the use of plant extracts, in particular, for the synthesis of ZnO NPs. The modifications of ZnO with organic (carboxylic acid, silanes) and inorganic (metal oxides) compounds and polymer matrices have then been described. The multitudinous applications of ZnO NPs across a variety of fields such as the rubber industry, pharmaceutical industry, cosmetics, textile industry, opto-electronics and agriculture have been presented. Elaborative narratives on the photocatalytic and a variety of biomedical applications of ZnO have also been included. The ecotoxic impacts of ZnO NPs have additionally been briefly highlighted. Finally, efforts have been made to examine the current challenges and future scope of the synthetic modes and applications of ZnO NPs.

Pharmaceutical Applications of Quantum Dots

Nanotechnology has been utilized in developing novel drug formulations with minimal adverse effects. Nanoparticles in a lower size range with great surface area, increased potency, and easy permeability could be an approach for the treatment of cancer and other diseases. Unlike other nanoparticles, quantum dots have specific functional groups, have charges over their surface, and are extremely small in size (2-10nm), which makes them more permeable through tight junctions. Quantum dots are interesting materials that offer diagnosis and treatment concurrently. Quantum dots are reported to have several applications in pharmaceuticals as well as drug delivery, diagnosis, immunolabeling, and cell labeling tools. However, the existence of heavy metals in quantum dots such as cadmium poses a potential challenge for future medical applications, where quantum dots may be deliberately injected into the body. In this review, we are focusing on various pharmaceutical applications of quantum dots. Graphical Abstract.

Preparation and Applications of Organo-Silica Hybrid Mesoporous Silica Nanoparticles for the Co-Delivery of Drugs and Nucleic Acids

Combination therapies rely on the administration of more than one drug, with independent mechanisms of action, aiming to enhance the efficiency of the treatment. For an optimal performance, the implementation of such therapies requires the delivery of the correct combination of drugs to a specific cellular target. In this context, the use of nanoparticles (NP) as platforms for the co-delivery of multiple drugs is considered a highly promising strategy. In particular, mesoporous silica nanoparticles (MSN) have emerged as versatile building blocks to devise complex drug delivery systems (DDS). This review describes the design, synthesis, and application of MSNs to the delivery of multiple drugs including nucleic acids for combination therapies.

Zinc oxide nanoparticles: A comprehensive review on its synthesis, anticancer and drug delivery applications as well as health risks

In recent years, zinc oxide nanoparticles (ZnONPs) emerged as an excellent candidate in the field of optical, electrical, food packaging and particularly in biomedical research. ZnONPs show cancer cell specific toxicity via the pH-dependent (low pH) dissolution into Zn²⁺ ions, which generate reactive oxygen species and induce cytotoxicity in cancer cells. Further, ZnONPs have also been used as an effective carrier for the targeted delivery of several anticancer drugs into tumor cells. The increasing focus on ZnONPs resulted in the development of various synthesis approaches including chemical, pHysical, and green or biological for the manufacturing of ZnONPs. In this article, at first we have discussed the various synthesis methods of ZnONPs and secondly its biomedical applications. We have extensively reviewed the anticancer mechanism of ZnONPs on different types of cancers considering its size, shape and surface charge dependent cytotoxicity. Photoirradiation with UV light or NIR laser further increase its anticancer activity via synergistic chemo-photodynamic effect. The drug delivery applications of ZnONPs with special emphasis on drug loading mechanism, stimuli-responsive controlled release and therapeutic effects have also been discussed in this review. Finally, its side effects to vital body organs with mechanism via different exposure routes, the future direction of the ZnONPs research and application are also discussed.

Mesoporous silica nanoparticles: synthesis methods and their therapeutic use-recent advances

Mesoporous silica nanoparticles (MSNPs) are a particular example of innovative nanomaterials for the development of drug delivery systems. MSNPs have recently received more attention for biological and pharmaceutical applications due to their capability to deliver therapeutic agents. Due to their unique structure, they can function as an effective carrier for the delivery of therapeutic agents to mitigate diseases progress, reduce inflammatory responses and consequently improve cancer treatment. The potency of MSNPs for the diagnosis and management of various diseases has been studied. This literature review will take an in-depth look into the properties of various types of MSNPs (e.g. shape, particle and pore size, surface area, pore volume and surface functionalisation), and discuss their characteristics, in terms of cellular uptake, drug delivery and release. MSNPs will then be discussed in terms of their therapeutic applications (passive and active tumour targeting, theranostics, biosensing and immunostimulative), biocompatibility and safety issues. Also, emerging trends and expected future advancements of this carrier will be provided.

Influence of the Surface Functionalization on the Fate and Performance of Mesoporous Silica Nanoparticles

Mesoporous silica nanoparticles have been broadly applied as drug delivery systems owing to their exquisite features, such as excellent textural properties or biocompatibility. However, there are various biological barriers that prevent their proper translation into the clinic, including: (1) lack of selectivity toward tumor tissues, (2) lack of selectivity for tumoral cells and (3) endosomal sequestration of the particles upon internalization. In addition, their open porous structure may lead to premature drug release, consequently affecting healthy tissues and decreasing the efficacy of the treatment. First, this review will provide a comprehensive and systematic overview of the different approximations that have been implemented into mesoporous silica nanoparticles to overcome each of such biological barriers. Afterward, the potential premature and non-specific drug release from these mesoporous nanocarriers will be addressed by introducing the concept of stimuli-responsive gatekeepers, which endow the particles with on-demand and localized drug delivery.

Therapeutic Effect of Doxorubicin-Chlorin E6-Loaded Mesoporous Silica Nanoparticles Combined with Ultrasound on Triple-Negative Breast Cancer

Introduction

Sonodynamic Therapy (SDT) has good targeting and non-invasive advantages in solid cancers, but its antitumor effect is not sufficient to replace traditional treatments. Some studies that combined SDT with chemotherapy or nanoparticles have managed to enhance its efficiency and overcome the side effects of chemotherapy.

Materials and Methods

In this study, we synthesized and characterized mesoporous silica nanoparticles (MSN-DOX-Ce6) loaded with doxorubicin (DOX) and sonosensitizer, chlorin e6 (Ce6). Then, we conducted in vitro and in vivo experiments to explore the antitumor effect of MSN-DOX-Ce6 under ultrasound (US) treatment.

Results

The characterization tests showed that the nanoparticles are uniformly sized spheres with mesoporous structure, resulting in a high drug-loading efficiency. In the in vitro experiments, MSN-DOX-Ce6 could effectively inhibit cell proliferation under US but not more than other treatment groups. However, the in vivo studies showed that MSN-DOX-Ce6+US has better antitumor effect than DOX+Ce6+US or DOX alone on xenograft tumor-bearing mice.

Conclusion

In summary, MSNs showed a great potential for DOX and Ce6 delivery. We concluded that under US, MSN-DOX-Ce6 nanocomposites increase the antitumor effect of DOX and SDT and thereby are a potential treatment for solid tumors.

Succinylated casein-coated peptide-mesoporous silica nanoparticles as an antibiotic against intestinal bacterial infection

Increasing drug resistance necessitates the discovery of novel bactericides. Human defensin (HD) peptides can eliminate resistant bacteria and are promising candidates for next-generation antibiotics. T7E21R-HD5 is a potent bactericide designed by site mutations at enteric HD5. To facilitate the development of T7E21R-HD5 into an intestinal antibiotic, we employed a mesoporous silica nanoparticle (MSN) as the peptide carrier. Despite its ineffectiveness at killing bacteria, the MSN intensified the outer membrane penetration and inner membrane permeabilization abilities of T7E21R-HD5 and thus enhanced its antibacterial action against multidrug resistant (MDR) E. coli, which broadened the role of MSNs in drug delivery. For the reduction in T7E21R-HD5 losses in the stomach, we further modified MSN@T7E21R-HD5 with succinylated casein (SCN), a milk protein that can be specifically degraded by intestinal protease. SCN coating decreased T7E21R-HD5 release from the MSNs, especially in a highly acidic environment. The controlled release of MSN@T7E21R-HD5 from SCN encapsulation was confirmed in the presence of trypsin. MSN@T7E21R-HD5@SCN was nontoxic to host cells, and it was capable of inactivating MDR E. coli in vivo and alleviating intestinal inflammation by suppressing the production of inflammatory factors TNF-α, IL-1β, and MMP-9. This study provides a peptide-based nanobiotic with efficacy to combat intestinal infection, especially against drug-resistant bacteria. The biocompatible and readily prepared MSN/SCN delivery system may benefit further intestinal antibiotic design and promote the drug transformation of additional enterogenic functional molecules.

Preparation of a mesoporous silica-based nano-vehicle for dual DOX/CPT pH-triggered delivery

A dual doxorubicin/camptothecin (DOX/CPT) pH-triggered drug delivery mesoporous silica nanoparticle (MSN)-based nano-vehicle has been prepared. In this drug-delivery system (DDS), CPT is loaded inside the pores of the MSNs, while DOX is covalently attached to the surface of an aldehyde-functionalized MSN through a dihydrazide-polyethylene glycol chain. Thus, DOX and the linker act as pH-sensitive gatekeeper. The system is versatile and easy to assemble, not requiring the chemical modification of the drugs. While at physiological conditions the release of the drugs is negligible, at acidic pH a burst release of DOX and a gradual release of CPT take place. In vitro cytotoxicity tests have demonstrated that this DDS can deliver efficiently DOX and CPT for combination therapy.

pH-Responsive Mesoporous Silica and Carbon Nanoparticles for Drug Delivery

The application of nanotechnology to medicine constitutes a major field of research nowadays. In particular, the use of mesoporous silica and carbon nanoparticles has attracted the attention of numerous researchers due to their unique properties, especially when applied to cancer treatment. Many strategies based on stimuli-responsive nanocarriers have been developed to control the drug release and avoid premature release. Here, we focus on the use of the subtle changes of pH between healthy and diseased areas along the body to trigger the release of the cargo. In this review, different approximations of pH-responsive systems are considered: those based on the use of the host-guest interactions between the nanocarriers and the drugs, those based on the hydrolysis of acid-labile bonds and those based on supramolecular structures acting as pore capping agents.

Lipid–polymer hybrid nanoparticles for synergistic drug delivery to overcome cancer drug resistance

Co-delivery of a chemotherapeutic drug and a drug resistance inhibitor by lipid–polymer hybrid nanoparticles can effectively overcome tumor drug resistance.

Self-immolative polymers as novel pH-responsive gate keepers for drug delivery

A novel pH-sensitive nanocarrier based on mesoporous silica nanoparticles with self-immolative polymers blocking the pore openings is presented.

Safe approaches for camptothecin delivery: Structural analogues and nanomedicines

Twenty-(S)-camptothecin is a strongly cytotoxic molecule with excellent antitumor activity over a wide spectrum of human cancers. However, the direct formulation is limited by its poor water solubility, low plasmatic stability and severe toxicity, which currently limits its clinical use. As a consequence, two strategies have been developed in order to achieve safe and efficient delivery of camptothecin to target cells: structural analogues and nanomedicines. In this review, we summarize recent advances in the design, synthesis and development of camptothecin molecular derivatives and supramolecular vehicles, following a systematic classification according to structure-activity relationships (structural analogues) or chemical nature (nanomedicines). A series of organic, inorganic and hybrid materials are presented as nanoplatforms to overcome camptothecin restrictions in administration, biodistribution, pharmacokinetics and toxicity. Nanocarriers which respond to a variety of stimuli endogenously (e.g., pH, redox potential, enzyme activity) or exogenously (e.g., magnetic field, light, temperature, ultrasound) seem the best positioned therapeutic materials for optimal spatial and temporal control over drug release. The main goal of this review is to be used as a source of relevant literature for others interested in the field of camptothecin-based therapeutics. To this end, final remarks on the most important formulations currently under clinical trial are provided.

AIE Luminogen-Functionalized Hollow Mesoporous Silica Nanospheres for Drug Delivery and Cell Imaging

Hollow mesoporous silica nanospheres functionalized with aggregation-induced emission (AIE) luminogen tetraphenylethene were prepared by postgrafting method. The as-prepared inorganic-organic hybrid nanospheres show bright blue emission and good biocompatibility as shown by MTT assays. The large cavities of the materials enable high loading of the anticancer drug doxorubicin hydrochloride (DOX), and the mesoporous silica shells allow pH-dependent drug release. The materials can be effectively taken up by cells and function as luminescent bioprobes, demonstrating their potential application in imaging-guided therapy.