Three-in-One Self-Assembled Nanocarrier for Dual-Drug Delivery, Two-Photon Imaging, and Chemo-Photodynamic Synergistic Therapy

Are smart delivery systems the solution to overcome the lack of selectivity of current metallodrugs in cancer therapy?

Chemotherapeutic metallodrugs such as cisplatin and its derivatives are among the most widely applied anticancer treatments worldwide. Despite their clinical success, patients suffer from severe adverse effects while subjected to treatment due to platinum's low selectivity for tumour over healthy tissues. Additionally, intrinsic or acquired resistance to metallodrugs, as well as their inability to reach cancer metastases, often results in therapeutic failure. The evident need for highly efficient and specific treatments has driven the scientific community to research novel ways to surpass the stated limitations. Within this scenario, a rising number of smart drug delivery systems have been lately reported to target primary cancers or metastases, where the metallodrugs are released in a controlled and selective way triggered by specific tumour-related stimuli, thus suggesting a viable and attractive therapeutic approach. Herein, we discuss the main efforts undertaken in the past few years towards the smart delivery of metal-based drugs and drug candidates to tumour sites, particularly focusing on the pH- and/or redox-responsive targeted delivery of platinum and ruthenium anticancer complexes.

Photo-Driven Delivery of 125I-Labeled Nanomicelles for Nucleus-Targeted Internal Conversion Electron-Based Cancer Therapy

As a kind of high linear energy transfer (LET) radiation, internal conversion electrons are emitted from some radionuclides, such as ¹²⁵I, triggering severe DNA damage to tumor cells when transported into the nucleus. Herein, we develop a curcumin-loaded nanomicelle composed of a photosensitizer chlorin e6 (Ce6) and amphiphilic poly(ethylene glycol) (poly(maleic anhydride-alt-1-octadecene)-poly(ethylene glycol) (C₁₈-PMH-PEG)) to deliver ¹²⁵I into the nucleus under 660 nm laser irradiation, leading to the optimized imaging-guided internal conversion electron therapy of cancer. Ce6-containing nanomicelles (Ce6-C₁₈-PEG) self-assemble with nucleus-targeted curcumin (Cur), obtaining Ce6-C₁₈-PEG/Cur nanoparticles. After labeling Cur with ¹²⁵I, Ce6-C₁₈-PEG/Cur enables single-photon emission computed tomography and fluorescence imaging of the tumor, serving as a guide for follow-up laser irradiation. Notably, the 660 nm laser-triggered photodynamic reaction of Ce6 optimizes the delivery of Ce6-C₁₈-PEG/¹²⁵I-Cur at various stages, including tumor accumulation, cellular uptake, and lysosome escape, causing plenty of ¹²⁵I-Cur to enter the nucleus. By this strategy, Ce6-C₁₈-PEG/¹²⁵I-Cur showed optimal antitumor efficacy and high biosafety in mice treated with local 660 nm laser irradiation using efficient energy deposition of internally converted electrons over short distances. Therefore, our work provides a novel strategy to optimize ¹²⁵I delivery for tumor treatment.

Overcoming barriers in photodynamic therapy harnessing nano-formulation strategies

Photodynamic therapy (PDT) has been extensively investigated for decades for tumor treatment because of its non-invasiveness, spatiotemporal selectivity, lower side-effects, and immune activation ability. It can be a promising treatment modality in several medical fields, including oncology, immunology, urology, dermatology, ophthalmology, cardiology, pneumology, and dentistry. Nevertheless, the clinical application of PDT is largely restricted by the drawbacks of traditional photosensitizers, limited tissue penetrability of light, inefficient induction of tumor cell death, tumor resistance to the therapy, and the severe pain induced by the therapy. Recently, various photosensitizer formulations and therapy strategies have been developed to overcome these barriers. Significantly, the introduction of nanomaterials in PDT, as carriers or photosensitizers, may overcome the drawbacks of traditional photosensitizers. Based on this, nanocomposites excited by various light sources are applied in the PDT of deep-seated tumors. Modulation of cell death pathways with co-delivered reagents promotes PDT induced tumor cell death. Relief of tumor resistance to PDT with combined therapy strategies further promotes tumor inhibition. Also, the optimization of photosensitizer formulations and therapy procedures reduces pain in PDT. Here, a systematic summary of recent advances in the fabrication of photosensitizers and the design of therapy strategies to overcome barriers in PDT is presented. Several aspects important for the clinical application of PDT in cancer treatment are also discussed.

Supramolecular agents for combination of photodynamic therapy and other treatments

Photodynamic therapy (PDT) is a promising treatment for cancers such as superficial skin cancers, esophageal cancer, and cervical cancer. Unfortunately, PDT often does not have sufficient therapeutic benefits due to its intrinsic oxygen dependence and the limited permeability of irradiating light. Side effects from "always on" photosensitizers (PSs) can be problematic, and PDT cannot treat tumor metastases or recurrences. In recent years, supramolecular approaches using non-covalent interactions have attracted attention due to their potential in PS development. A supramolecular PS assembly could be built to maximize photodynamic effects and minimize side effects. A combination of two or more therapies can effectively address shortcomings while maximizing the benefits of each treatment regimen. Using the supramolecular assembly, it is possible to design a multifunctional supramolecular PS to exert synergistic effects by combining PDT with other treatment methods. This review provides a summary of important research progress on supramolecular systems that can be used to combine PDT with photothermal therapy, chemotherapy, and immunotherapy to compensate for the shortcomings of PDT, and it provides an overview of the prospects for future cancer treatment advances and clinical applications.

Dual-ligand supramolecular nanofibers inspired by the renin-angiotensin system for the targeting and synergistic therapy of myocardial infarction

Rationale: The compensatory activation of the renin-angiotensin system (RAS) after myocardial infarction (MI) plays a crucial role in the pathogenesis of heart failure. Most existing studies on this subject focus on mono- or dual-therapy of blocking the RAS, which exhibit limited efficacy and often causes serious adverse reactions. Few studies have been conducted on targeted therapy based on the activated RAS post-MI. Thus, the development of multiple-functional nanomedicine with concurrent targeting ability and synergistic therapeutic effect against RAS may show great promise in improving cardiac function post-MI.

Methods: We utilized a cooperative self-assembly strategy constructing supramolecular nanofibers— telmisartan-doped co-assembly nanofibers (TDCNfs) to counter-regulate RAS through targeted delivery and combined therapy. TDCNfs were prepared through serial steps of solvent exchange, heating incubation, gelation, centrifugation, and lyophilization, in which the telmisartan was doped in the self-assembly process of Ang1-7 to obtain the co-assembly nanofibers wherein they act as both therapeutic agents and target-guide agents.

Results: TDCNfs exhibited the desired binding affinity to the two different receptors, AT1R and MasR. Through the dual ligand-receptor interactions to mediate the coincident downstream pathways, TDCNfs not only displayed favorably targeted properties to hypoxic cardiomyocytes, but also exerted synergistic therapeutic effects in apoptosis reduction, inflammatory response alleviation, and fibrosis inhibition in vitro and in vivo, significantly protecting cardiac function and mitigating post-MI adverse outcomes.

Conclusion: A dual-ligand nanoplatform was successfully developed to achieve targeted and synergistic therapy against cardiac deterioration post-MI. We envision that the integration of multiple therapeutic agents through supramolecular self-assembly would offer new insight for the systematic and targeted treatment of cardiovascular diseases.

A lysosomal targeted NIR photosensitizer for photodynamic therapy and two-photon fluorescence imaging

A lysosome-targeting NIR photosensitizer has been developed for two-photon fluorescence imaging and imaging-guided photodynamic therapy via lysosomal-damage-mediated apoptosis.

Nanomaterials with Supramolecular Assembly Based on AIE Luminogens for Theranostic Applications

One of the major pursuits of biomedical science is to develop advanced strategies for theranostics, which is expected to be an effective approach for achieving the transition from conventional medicine to precision medicine. Supramolecular assembly can serve as a powerful tool in the development of nanotheranostics with accurate imaging of tumors and real-time monitoring of the therapeutic process upon the incorporation of aggregation-induced emission (AIE) ability. AIE luminogens (AIEgens) will not only enable fluorescence imaging but will also aid in improving the efficacy of therapies. Furthermore, the fluorescent signals and therapeutic performance of these nanomaterials can be manipulated precisely owing to the reversible and stimuli-responsive characteristics of the supramolecular systems. Inspired by rapid advances in this field, recent research conducted on nanotheranostics with the AIE effect based on supramolecular assembly is summarized. Here, three representative strategies for supramolecular nanomaterials are presented as follows: a) supramolecular self-assembly of AIEgens, b) the loading of AIEgens within nanocarriers with supramolecular assembly, and c) supramolecular macrocycle-guided assembly via host-guest interactions. Meanwhile, the diverse applications of such nanomaterials in diagnostics and therapeutics have also been discussed in detail. Finally, the challenges of this field are listed in this review.

Amino-Functionalized Mesoporous Silica Nanoparticle-Encapsulated Octahedral Organoruthenium Complex as an Efficient Platform for Combatting Cancer

In the process of synthesis of a new drug, as important as the drug itself is the formulation used, because the same compound can present a very different efficacy depending on how it is administered. In this work, we demonstrate how the antitumor capacity of a new octahedral organoruthenium complex, [Ru(ppy-CHO)(phen)₂][PF₆] is affected by its encapsulation in different types of mesoporous silica nanoparticles. The interactions between the Ru complex and the silica matrix and how these interactions are affected at two different pHs (7.4 and 5.4, mimicking physiological and endolysosomal acidic conditions, respectively) have been studied. The encapsulation has also been shown to affect the induction of apoptosis and necrosis and progression of the cell cycle compared to the free drug. The encapsulation of the Ru complex in nanoparticles functionalized with amino groups produced very high anticancer activity in cancer cells in vitro, especially against U87 glioblastoma cells, favoring cellular internalization and significantly increasing the anticancer capacity of the initial non-encapsulated Ru complex.

Host–guest interaction based supramolecular photodynamic therapy systems: a promising candidate in the battle against cancer

This article summarizes recent advances in the development of supramolecular photodynamic therapy based on host–guest interactions.

Facile construction of shape-regulated β-cyclodextrin-based supramolecular self-assemblies for drug delivery

Although supramolecular prodrug self-assemblies have been proven as efficient nanocarriers for cancer therapy, tedious synthesis procedures have made their practical applications more difficult. In this paper, β-cyclodextrin-based supramolecular self-assemblies (SSAs) were directly constructed by utilizing β-cyclodextrin trimer (β-CD₃) as the host unit and unmodified curcumin as the guest unit. Due to the adjustment of host-guest inclusion and hydrophilic-hydrophobic interactions occurring in the SSAs, their morphology could be readily tuned by changing the ratio of the two components. Different self-assembly morphologies, such as spherical complex micelles, spindle-like complex micelles and multi-compartment vesicles, were obtained. Furthermore, basic cell experiments were performed to study the corresponding effects of the SSA shape on their biological properties. Compared to the other micelles, the spindle-like complex micelles exhibited enhanced cellular toxicity, uptake behaviors and apoptosis rates, and the spherical complex micelles exhibited poor performance. The performance of the multi-compartment vesicles was similar to that of the spindle-like complex micelles. The facile construction of these shape-regulated SSAs and their different cellular biological properties might be valuable in the controlled drug release field.

Receptor-Mediated and Tumor-Microenvironment Combination-Responsive Ru Nanoaggregates for Enhanced Cancer Phototheranostics

Although phototherapy has been considered as an emerging and promising technology for cancer therapy, its therapeutic specificity and efficacy are severely limited by nonspecific uptake by normal tissues, tumor hypoxia, and so on. Herein, combination-responsive strategy (CRS) is applied to develop one kind of hyaluronic acid-hybridized Ru nanoaggregates (HA-Ru NAs) for enhanced cancer phototherapy via the reasonable integration of receptor-mediated targeting (RMT) and tumor-microenvironment responsiveness (TMR). In this nanosystem, the HA component endows HA-Ru NAs with RMT characteristic to selectively recognize CD44-overexpressing cancer cells, whereas the Ru nanocomponent makes HA-Ru NAs have TMR therapy activity. Specially, the Ru nanocomponent not only has near-infrared-mediated photothermal and photodynamic functions but also can catalyze H₂O₂ in tumor tissue to produce O₂ for the alleviation of tumor hypoxia and toxic •OH for chemodynamic therapy. Benefitting from these, HA-Ru NAs can be considered as a promising kind of CRS nanoplatforms for synergistic photothermal/photodynamic/chemodynamic therapies of cancer, which will not only effectively improve the phototherapeutic specificity and efficacy but also simplify the therapeutic nanosystems. Meanwhile, HA-Ru NAs can serve as a photoacoustic and computed tomography imaging contrast agent to monitor tumors. Such CRS nanoplatforms hold significant potential in improving therapeutic specificity and efficacy for enhanced cancer phototheranostics.

A CD44-Targeting Programmable Drug Delivery System for Enhancing and Sensitizing Chemotherapy to Drug-Resistant Cancer

Programmable drug delivery systems hold great promise to enhance cancer treatment. Herein, a programmable drug delivery system using a chondroitin sulfate (CS)-based composite nanoparticle was developed for enhancing and sensitizing chemotherapy to drug-resistant cancer. The nanoparticle was composed of a cross-linked CS hydrogel shell and hydrophobic cores containing both free drugs and CS-linked prodrugs. Interestingly, the nanoparticle could mediate tumor-specific CD44 targeting. After specific cellular uptake, the payloads were suddenly released because of the decomposition of the CS shell, and the free drug molecules with synergistic effects induced tumor-specific cytotoxicity rapidly. Subsequently, the inner cores of the nanoparticles sustainedly release their cargos in drug-resistant tumor cells to keep the effective drug concentration against the drug efflux mediated by P-glycoprotein. CS dissociated from the outer shell and sensitized cancer cells to the antitumor drugs through downregulation of Bcl-XL, an antiapoptosis protein. Such a programmable drug delivery system with specific tumor-targeting and sensitized therapy is promising for rational drug delivery and provides more versatility for controlled release in biomedical applications.

Evolution of Nanoparticle-Mediated Photodynamic Therapy: From Superficial to Deep-Seated Cancers

Enthusiasm for photodynamic therapy (PDT) as a potential therapeutic intervention for cancer has increased exponentially in recent decades. Photodynamic therapy constitutes a clinically approved, minimally invasive treatment modality that uses a photosensitizer (light absorbing molecule) and light to kill cancer cells. The principle of PDT is, when irradiated with a light of a suitable wavelength, a photosensitizer absorbs the light energy and generates cytotoxic free radicals through various mechanisms. The overall efficiency of PDT depends on characteristics of activation light and in-situ dosimetry, including the choice of photosensitizer molecule, wavelength of the light, and tumor location and microenvironment, for instance, the use of two-photon laser or an X-ray irradiator as the light source increases tissue-penetration depth, enabling it to achieve deep PDT. In this mini-review, we discuss the various designs and strategies for single, two-photon, and X-ray-mediated PDT for improved clinical outcomes.

A tumor-targeting Ru/polysaccharide/protein supramolecular assembly with high photodynamic therapy ability

A supramolecular assembly was conveniently constructed and exhibited excellent photodynamic therapy selectivity towards tumor cells and negligible toxicity towards normal cells.

Development of self-assembled nanocarriers to enhance antitumor efficacy of docetaxel trihydrate in MDA-MB-231 cell line

Self-assembled nanocarriers (SANs) as a novel colloidal controlled delivery for docetaxel trihydrate (DTX) were engineered by high-pressure homogenization method to overcome the several clinical problems. Drug-excipient compatibility was studied using DSC and FTIR spectroscopy. The fabricated SANs was characterized by particle size, zeta potential, and SEM. QbD based central composite design of experiment was employed for formula optimization. The cell viability of DTX-hydroalcoholic solution (DTX-HA) and DTX-loaded SANs has been determined in MDA-MB-231 cell line by MTT assay. The stability study of selected SANs formulations were carried out at various storage conditions as per ICH guidelines. The summary of results obtained shows high drug content with higher entrapment efficiency (91.23 ± 3.41% w/w) of DTX-loaded SANs. It shows diffusion controlled release of DTX over the period of 12 h which is higher than DTX-HA solution, releases the DTX within 4 h. The MTT assay expressed lower cellular viability and improved cell inhibition leads to increase cytotoxicity of formulations towards cells. The stability study reveals stability of DTX-loaded SANs formulations at various storage conditions over a period of three months. The strong experimental evidence confirms the SANs as an effective approach to formulate the controlled delivery system of antineoplastics with improved stability.