Simple and Multifunctional Natural Self-Assembled Sterols with Anticancer Activity-Mediated Supramolecular Photosensitizers for Enhanced Antitumor Photodynamic Therapy

Natural Products from Herbal Medicine Self-Assemble into Advanced Bioactive Materials

Novel biomaterials are becoming more crucial in treating human diseases. However, many materials require complex artificial modifications and synthesis, leading to potential difficulties in preparation, side effects, and clinical translation. Recently, significant progress has been achieved in terms of direct self-assembly of natural products from herbal medicine (NPHM), an important source for novel medications, resulting in a wide range of bioactive supramolecular materials including gels, and nanoparticles. The NPHM-based supramolecular bioactive materials are produced from renewable resources, are simple to prepare, and have demonstrated multi-functionality including slow-release, smart-responsive release, and especially possess powerful biological effects to treat various diseases. In this review, NPHM-based supramolecular bioactive materials have been revealed as an emerging, revolutionary, and promising strategy. The development, advantages, and limitations of NPHM, as well as the advantageous position of NPHM-based materials, are first reviewed. Subsequently, a systematic and comprehensive analysis of the self-assembly strategies specific to seven major classes of NPHM is highlighted. Insights into the influence of NPHM structural features on the formation of supramolecular materials are also provided. Finally, the drivers and preparations are summarized, emphasizing the biomedical applications, future scientific challenges, and opportunities, with the hope of igniting inspiration for future research and applications.

Self-assembled Abietic acid encapsulated nanoparticles to improve the stability of Proanthocyanin B2

Procyanidin B2 (Pac B2) has attracted much attention due to its strong antioxidant activity, but poor in vivo stability limits its wide application in food and medicine. In this paper, composite nanoparticles (NPs) were constructed using abietic acid (AA) as a carrier, which significantly enhanced Pac B2 stability. A spherical morphology and average diameter of 396.05 nm were observed in AA-Pac B2 NPs synthesized by solvent co-precipitation. Pac B2 encapsulation was 11.28 %, and thermal stability is improved. Infrared, Ultraviolet spectrum, and MD (molecular dynamics) spectroscopy revealed hydrogen bonding and hydrophobic interaction between AA and Pac B2. For up to 2 h at 37 °C, Pac B2 can be sustainably released in simulated gastric and intestinal fluids. In vitro, AA-Pac B2 NPs at the same concentration exhibited higher bioavailability and uptake efficiency than free Pac B2. The data demonstrate the potential of AA NPs for improving polyphenol thermal stability and bioavailability.

Natural gambogic acid-tuned self-assembly of nanodrugs towards synergistic chemophototherapy against breast cancer

Gambogic acid (GA) as a naturally derived chemotherapeutic agent is of increasing interest for antitumor therapy. However, current research mainly focuses on improving the pharmacological properties to overcome the shortcomings in clinical applications or as a synergistic anticancer agent in combination with chemotherapy and chemophototherapy. Yet, the material properties of GA (e.g., self-assembly) are often neglected. Herein, we validated the self-assembly function of GA and its huge potential as a single-component active carrier for synergistic delivery using pyropheophorbide-a (PPa) as a drug model. The results showed that self-assembled GA drives the formation of nano-GA/PPa mainly through noncovalent interactions such as π-π stacking, hydrophobic interactions, and hydrogen bonding. Additionally, although no significant differences in cytotoxicity were found between the individual in vitro chemotherapy and combined chemophototherapy, the as-prepared nano-GA/PPa exhibits remarkably improved water solubility and multiple favorable therapeutic features, leading to a prominent in vivo photochemotherapy efficiency of 89.3% inhibition rate with reduced hepatotoxicity of GA. This work highlights the potential of self-assembled GA as a drug delivery carrier for synergistic biomedical applications.

Morusin-Cu(II)-indocyanine green nanoassembly ignites mitochondrial dysfunction for chemo-photothermal tumor therapy

Nanoscale drug delivery systems derived from natural bioactive materials accelerate the innovation and evolution of cancer treatment modalities. Morusin (Mor) is a prenylated flavonoid compound with high cancer chemoprevention activity, however, the poor water solubility, low active pharmaceutical ingredient (API) loading content, and instability compromise its bioavailability and therapeutic effectiveness. Herein, a full-API carrier-free nanoparticle is developed based on the self-assembly of indocyanine green (ICG), copper ions (Cu2+) and Mor, termed as IMCNs, via coordination-driven and π-π stacking for synergistic tumor therapy. The IMCNs exhibits a desirable loading content of Mor (58.7 %) and pH/glutathione (GSH)-responsive motif. Moreover, the photothermal stability and photo-heat conversion efficiency (42.8 %) of IMCNs are improved after coordination with Cu2+ and help to achieve photothermal therapy. Afterward, the released Cu2+ depletes intracellular overexpressed GSH and mediates Fenton-like reactions, and further synergizes with ICG at high temperatures to expand oxidative damage. Furthermore, the released Mor elicits cytoplasmic vacuolation, expedites mitochondrial dysfunction, and exerts chemo-photothermal therapy after being combined with ICG to suppress the migration of residual live tumor cells. In vivo experiments demonstrate that IMCNs under laser irradiation could excellently inhibit tumor growth (89.6 %) through the multi-modal therapeutic performance of self-enhanced chemotherapy/coordinated-drugs/ photothermal therapy (PTT), presenting a great potential for cancer therapy.

Nanoparticle encapsulation using self-assembly abietic acid to improve oral bioavailability of curcumin

This research constructed composite nanoparticles (NPs) using abietic acid (AA) as a carrier for significantly enhancing the bioavailability of curcumin (CCM). CCM-loaded AA NPs were synthesized using a low-energy microemulsification method, and the obtained nanoparticles had a spherical morphology with an average diameter of 458.66 nm, a narrow size distribution and a negative surface charge of -19.13 mV. The encapsulation efficiency of CCM was 17.98 %, while its solubility was 20-fold that of free curcumin. FITR, UV, and MD revealed hydrogen bonds and hydrophobic forces between AA and CCM. Thein-vitrorelease profile showed sustainable release of CCM in simulated gastric and intestinal fluids up to 2 h at 37 °C. In cellular studies, CCM-loaded AA NPs with the same CCM concentration exhibited greater bioaccessibility and bioavailability than free CCM. These data suggested a possible utilization of AA NPs in improving water solubility, bioavailability and activity of lipophilic bioactive food factors.

Aptamer-based self-assembled nanomicelle enables efficient and targeted drug delivery

Nucleic acid aptamer-based nanomicelles have great potential for nanomedicine and nanotechnology applications. However, amphiphilic aptamer micelles are known to be inherently unstable upon interaction with cell membranes in the physiological environment, thus potentially compromising their specific targeting against cancer cells. This flaw is addressed in the present work which reports a superstable micellar nanodelivery system as an amphiphilic copolymer self-assembled micelle composed of nucleic acid aptamer and polyvalent hydrophobic poly(maleic anhydride-alt-1-octadecene) (C18PMH). Using Ce6 as a drug model, these C18-aptamer micelles exhibit efficient tumor-targeting and -binding ability, facilitating the entry of Ce6 into targeted cells for photodynamic therapy. In addition, they can be loaded with other hydrophobic drugs and still demonstrate favorable therapeutic effects. As such, these C18-aptamer micelles can serve as a universal platform for loading multiple drugs, providing a safer and more effective solution for treating cancer.

β-Sitosterol as a Promising Anticancer Agent for Chemoprevention and Chemotherapy: Mechanisms of Action and Future Prospects

Cancer is one of the primary causes of death worldwide, and its incidence continues to increase yearly. Despite significant advances in research, the search for effective and nontoxic preventive and therapeutic agents remains greatly important. Cancer is a multimodal disease, where various mechanisms play significant roles in its occurrence and progression. This highlights the need for multitargeted approaches that are not only safe and inexpensive but also provide effective alternatives for current therapeutic regimens. β-Sitosterol (SIT), the most abundant phytosterol found in various plant foods, represents such an option. Preclinical evidence over the past few decades has overwhelmingly shown that SIT exhibits multiple anticancer activities against varied cancers, such as liver, cervical, colon, stomach, breast, lung, pancreatic, and prostate cancers, in addition to leukemia, multiple myeloma, melanoma, and fibrosarcoma. In this article, we present the latest advances and perspectives on SIT-systematically summarizing its antitumor mechanisms of action into 7 main sections and combining current challenges and prospects-for its use as a promising agent for cancer prevention and treatment. In particular, SIT plays a role in cancer prevention and treatment mainly by enhancing apoptosis, inducing cell cycle arrest, bidirectionally regulating oxidative stress, improving metabolic reprogramming, inhibiting invasion and metastasis, modulating immunity and inflammation, and combating drug resistance. Although SIT holds such great promise, the poor aqueous solubility and bioavailability coupled with low targeting efficacy limit its therapeutic efficacy and clinical application. Further research on novel drug delivery systems may improve these deficiencies. Overall, through complex and pleiotropic mechanisms, SIT has good potential for tumor chemoprevention and chemotherapy. However, no clinical trials have yet proven this potential. This review provides theoretical basis and rationality for the further design and conduct of clinical trials to confirm the anticancer activity of SIT.

Recent advances in type I organic photosensitizers for efficient photodynamic therapy for overcoming tumor hypoxia

Photodynamic therapy (PDT) with an oxygen-dependent character is a noninvasive therapeutic method for cancer treatment. However, its clinical therapeutic effect is greatly restricted by tumor hypoxia. What's more, both PDT-mediated oxygen consumption and microvascular damage aggravate tumor hypoxia, thus, further impeding therapeutic outcomes. Compared to type II PDT with high oxygen dependence and high oxygen consumption, type I PDT with less oxygen consumption exhibits great potential to overcome the vicious hypoxic plight in solid tumors. Type I photosensitizers (PSs) are significantly important for determining the therapeutic efficacy of PDT, which performs an electron transfer photochemical reaction with the surrounding oxygen/substrates to generate highly cytotoxic free radicals such as superoxide radicals (˙O₂^-) as type I ROS. In particular, the primary precursor (˙O₂^-) would progressively undergo a superoxide dismutase (SOD)-mediated disproportionation reaction and a Haber-Weiss/Fenton reaction, yielding higher cytotoxic species (˙OH) with better anticancer effects. As a result, developing high-performance type I PSs to treat hypoxic tumors has become more and more important and urgent. Herein, the latest progress of organic type I PSs (such as AIE-active cationic/neutral PSs, cationic/neutral PSs, polymer-based PSs and supramolecular self-assembled PSs) for monotherapy or synergistic therapeutic modalities is summarized. The molecular design principles and strategies (donor-acceptor system, anion-π⁺ incorporation, polymerization and cationization) are highlighted. Furthermore, the future challenges and prospects of type I PSs in hypoxia-overcoming PDT are proposed.

Bionic natural small molecule co-assemblies towards targeted and synergistic Chemo/PDT/CDT

BACKGROUND

Multi-component nano-delivery systems based on chemotherapy (chemo)- photodynamic therapy (PDT)- chemodynamic therapy (CDT) have gained increased attention as a promising strategy to improve clinical outcomes in cancer treatment. However, there remains a challenge in developing biodegradable, biocompatible, less toxic, yet highly efficient multicomponent nanobased drug delivery systems (DDS). Here, our study presents the screening and development of a novel DDS based on co-assemblies natural small molecule (NSMs). These molecules (oleanolic acid, and betulinic acid) are combined with photosensitizers Chlorine6 (Ce6) and Cu²⁺ that are encapsulated by tumor cell membranes. This nanocarrier encapsulated in tumor cell membranes achieved good tumor targeting and a significant improvement in tumor accumulation.

METHODS

A reprecipitation method was used to prepare the co-assembled nanocarrier, followed by the introduction of Cu^2 + into the DDS (OABACe6 NPs). Then, by wrapping the surface of NPs with the cell membranes of 4T1 which is a kind of mouse breast cancer cells (CM@OABACe6/Cu NPs). and analysis of its structure and size distribution with UV-Vis, XPS, FT-IR, SEM, TEM, and DLS. The synergistic effects of in vitro chemotherapy, CDT and PDT and targeting were also validated by cellular and animal studies.

RESULTS

It was shown that CM@OABACe6/Cu NPs achieved good tumor targeting and a significant improvement in tumor accumulation. In the composite nano-assembly, the NSMs work together with the Ce6 to provide effective and safe chemo and PDT. Moreover, the effect of reduced PDT due to the depletion of reactive oxygen species (ROS) by excess glutathione (GSH) in the tumor can be counteracted when Cu^2 + is introduced. More importantly, it also confers CDT through a Fenton-like catalytic reaction with H₂O overexpressed at the tumor site.

CONCLUSIONS

By constructing CM@OABACe6/Cu NPs with homologous targeting, we create a triple synergistic platform for cancer therapy using PDT, chemo, and CDT. We propose here a novel combinatorial strategy for designing more naturally co-assembled small molecules, especially for the development of multifunctional synergistic therapies that utilize NSMs.

Recent advances in natural small molecules as drug delivery systems

Drug delivery systems (DDSs) are a multidisciplinary approach toward the effective delivery of drugs to their target sites. Natural small molecule (NSM) compounds with anticancer activity, self-assembly and co-assembly functions show great potential for application as novel DDSs in the biomedical field. NSMs are widely sourced, have many modification sites, and readily form hydrogen bonds, π-π interactions, van der Waals interactions, and other non-covalent bonds in solvents, resulting in ordered structures. Moreover, their good biocompatibility and bioactivity allow compositions based on these compounds to be used in life science applications such as tissue engineering, drug delivery and cell imaging, showing the potential medical value of NSMs as DDSs. In this review, we summarise the role, assembly principles and applications of natural products such as triterpenoids, diterpenoids, sterols, alkaloids and polysaccharides in the construction of small molecule systems, which are expected to provide an important reference for the development of more active natural nanomaterials and the study of single or multi-component interactions.

Photosensitive pro-drug nanoassemblies harboring a chemotherapeutic dormancy function potentiates cancer immunotherapy

Immunotherapy combined with effective therapeutics such as chemotherapy and photodynamic therapy have been shown to be a successful strategy to activate anti-tumor immune responses for improved anticancer treatment. However, developing multifunctional biodegradable, biocompatible, low-toxic but highly efficient, and clinically available transformed nano-immunostimulants remains a challenge and is in great demand. Herein, we report and design of a novel carrier-free photo-chemotherapeutic nano-prodrug COS-BA/Ce6 NPs by combining three multifunctional components-a self-assembled natural small molecule betulinic acid (BA), a water-soluble chitosan oligosaccharide (COS), and a low toxic photosensitizer chlorin e6 (Ce6)-to augment the antitumor efficacy of the immune adjuvant anti-PD-L1-mediated cancer immunotherapy. We show that the designed nanodrugs harbored a smart and distinctive "dormancy" characteristic in chemotherapeutic effect with desired lower cytotoxicity, and multiple favorable therapeutic features including improved ¹O₂ generation induced by the reduced energy gap of Ce6, pH-responsiveness, good biodegradability, and biocompatibility, ensuring a highly efficient, synergistic photochemotherapy. Moreover, when combined with anti-PD-L1 therapy, both nano-coassembly based chemotherapy and chemotherapy/photodynamic therapy (PDT) could effectively activate antitumor immunity when treating primary or distant tumors, opening up potentially attractive possibilities for clinical immunotherapy.

Carrier-free nanoplatforms from natural plants for enhanced bioactivity

BACKGROUND

Natural plants as well as traditional Chinese medicine have made outstanding contributions to the health and reproduction of human beings and remain the basis and major resource for drug innovation. Carrier-free nanoplatforms completely self-assembled by pure molecules or therapeutic components have attracted increasing attention due to their advantages of improved pharmacodynamics/pharmacokinetics, reduced toxicity, and high drug loading. In recent years, carrier-free nanoplatforms produced by self-assembly from natural plants have contributed to progress in a variety of therapeutic modalities. Notably, these nanoplatforms based on the interactions of components from different natural plants improve efficiency and depress toxicity.

AIM OF REVIEW

In this review, different types of self-assembled nanoplatforms are first summarized, mainly including nanoassemblies of pure small molecules isolated from different plants, extracellular vesicles separated from fresh plants, charcoal nanocomponents obtained from charred plants, and nanoaggregates from plants formulae decoctions. Key Scientific Concepts of Review: We mainly focus on composition, self-assembly mechanisms, biological activity and modes of action. Finally, a future perspective of existing challenges with respect to the clinical application of plant-based carrier-free nanoplatforms is discussed, which may be instructive to further develop effective carrier-free nanoplatforms from natural plants in the future.

Nanomaterials in Animal Husbandry: Research and Prospects

Anti-inflammatory, antiviral, and anti-cancer treatments are potential applications of nanomaterials in biology. To explore the latest discoveries in nanotechnology, we reviewed the published literature, focusing on co-assembled nanoparticles for anti-inflammatory and anti-tumor properties, and their applications in animal husbandry. The results show that nanoparticles have significant anti-inflammation and anti-tumor effects, demonstrating broad application prospects in animal breeding. Furthermore, pooled evidence suggests that the mechanism is to have a positive impact on inflammation and tumors through the specific drug loading by indirectly or directly targeting the disease sites. Because the precise regulatory mechanism remains unclear, most studies have focused on regulating particular sites or even specific genes in the nucleus by targeting functional co-assembled nanoparticles. Hence, despite the intriguing scenarios for nanotechnology in farmed animals, most results cannot yet be translated into field applications. Overall, nanomaterials outperformed similar materials in terms of anti-inflammatory and anti-tumor. Nanotechnology also has promising applications in animal husbandry and veterinary care, and its application and development in animal husbandry remain an exciting area of research.

Supramolecular assemblies based on natural small molecules: Union would be effective

Natural products have been used to prevent and treat human diseases for thousands of years, especially the extensive natural small molecules (NSMs) such as terpenoids, steroids and glycosides. A quantity of studies are confined to concern about their chemical structures and pharmacological activities at the monomolecular level, whereas the spontaneous assemblies of them in liquids yielding supramolecular structures have not been clearly understood deeply. Compared to the macromolecules or synthetic small molecular compounds, NSMs have the inherent advantages of lower toxicity, better biocompatibility, biodegradability and biological activity. Self-assembly of single component and multicomponent co-assembly are unique techniques for designing supramolecular entities. Assemblies are of special significance due to their range of applications in the areas of drug delivery systems, pollutants capture, materials synthesis, etc. The assembled mechanism of supramolecular NSMs which are mainly driven by multiple non-covalent interactions are summarized. Furthermore, a new hypothesis aimed to interpret the integration effects of multi-components of traditional Chinese medicines (TCMs) inspired on the theory of supramolecular assembly is proposed. Generally, this review can enlighten us to achieve the qualitative leap for understanding natural products from monomolecule to supramolecular structures and multi-component interactions, which is valuable for the intensive research and application.

Photodynamic Anti-Bacteria by Carbon Dots and Their Nano-Composites

The misuse of many types of broad-spectrum antibiotics leads to increased antimicrobial resistance. As a result, the development of a novel antibacterial agent is essential. Photodynamic antimicrobial chemotherapy (PACT) is becoming more popular due to its advantages in eliminating drug-resistant strains and providing broad-spectrum antibacterial resistance. Carbon dots (CDs), zero-dimensional nanomaterials with diameters smaller than 10 nm, offer a green and cost-effective alternative to PACT photosensitizers. This article reviewed the synthesis methods of antibacterial CDs as well as the recent progress of CDs and their nanocomposites in photodynamic sterilization, focusing on maximizing the bactericidal impact of CDs photosensitizers. This review establishes the base for future CDs development in the PACT field.

Structure and Biological Activity of Ergostane-Type Steroids from Fungi

Mushrooms are known not only for their taste but also for beneficial effects on health attributed to plethora of constituents. All mushrooms belong to the kingdom of fungi, which also includes yeasts and molds. Each year, hundreds of new metabolites of the main fungal sterol, ergosterol, are isolated from fungal sources. As a rule, further testing is carried out for their biological effects, and many of the isolated compounds exhibit one or another activity. This study aims to review recent literature (mainly over the past 10 years, selected older works are discussed for consistency purposes) on the structures and bioactivities of fungal metabolites of ergosterol. The review is not exhaustive in its coverage of structures found in fungi. Rather, it focuses solely on discussing compounds that have shown some biological activity with potential pharmacological utility.

Phytonanomaterials as therapeutic agents and drug delivery carriers

Medicinal plants have been a major resource for drug discovery. Emerging evidence shows that in addition to pharmacologically active components, medicinal plants also contain phytochemical nanomaterials, or phytonanomaterials, which form nanoparticles for drug delivery. In this review, we examine the evidence supporting the existence of phytonanomaterials. Next, we review identification, isolation, and classification of phytonanomaterials, characteristics of phytonanomaterial-derived nanoparticles, and molecular mechanisms of phytonanomaterial assembly. We will then summarize the current progress in exploring phytonanomaterial-derived NPs as therapeutic agents and drug delivery carriers for disease treatment. Last, we will provide perspectives on future discovery and applications of phytonanomaterials.

Effective tumor vessel barrier disruption mediated by perfluoro-N-(4-methylcyclohexyl) piperidine nanoparticles to enhance the efficacy of photodynamic therapy

BACKGROUND

Currently, limited tumor drug permeation, poor oxygen perfusion and immunosuppressive microenvironments are the most important bottlenecks that significantly reduce the efficacy of photodynamic therapy (PDT). The main cause of these major bottlenecks is the platelet activation maintained abnormal tumor vessel barriers. Thus, platelet inhibition may present a new way to most effectively enhance the efficacy of PDT. However, to the best of our knowledge, few studies have validated the effectiveness of such a way in enhancing the efficacy of PDT both in vivo and in vitro. In this study, perfluoro-N-(4-methylcyclohexyl) piperidine-loaded albumin (PMP@Alb) nanoparticles were discovered, which possess excellent platelet inhibition ability. After PMP@Alb treatment, remarkably enhanced intra-tumoral drug accumulation, oxygen perfusion and T cell infiltration could be observed owing to the disrupted tumor vessel barriers. Besides, the effect of ICG@Lip mediated PDT was significantly amplified by PMP@Alb nanoparticles. It was demonstrated that PMP@Alb could be used as a useful tool to improve the efficacy of existing PDT by disrupting tumor vessel barriers through effective platelet inhibition.

Exploring the self-assembly mechanism and effective synergistic antitumor chemophototherapy of a biodegradable and glutathione responsive ursolic acid prodrug mediated photosensitive nanodrug

Supermolecularly assembled photochemotherapeutic nanocomposites composed of pure drug small molecules are promising for synergistically improved tumor therapy, yet potential multiple challenges remain to be addressed. Herein, we rationally designed a novel multifunctional small molecule disulfide modified natural pentacyclic triterpene of ursolic acid (UASS) that simultaneously possesses self-assembly ability, glutathione (GSH) responsivity, anticancer activity, biocompatibility and biodegradability and further constructed carrier-free GSH-sensitive photosensitive nanocomposite UASS-Ce6 NPs for safe and synergistically improved chemophototherapy. Specifically, UASS-Ce6 NPs exhibit improved 1O2 generation by reducing the energy gap (ΔEST) of Ce6 as determined by density functional theory. Meanwhile, molecular dynamics simulation revealed the possible reasons why free UASS self-assembles and UASS-Ce6 NPs with different assembled morphologies may be primarily attributed to the coplanar arrangement of UASS dimer units. Importantly, via noncovalent π-stacking and hydrophobic interactions, the resulting co-assemblies showed improved water solubility, increased intercellular ROS generation, desirable GSH sensibility, excellent biocompatibility, and enhanced tumor accumulation accompanied by rapid biodegradation, thus leading to significant in vitro and in vivo synergistic antitumor efficacy with favorable biosafety. This study provides a promising insight into the development of a self-assembled active single component platform with desirable stimuli responsiveness and biosafety toward synergistic antitumor therapy based on terpenoid natural small molecules.

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.

Assembled small organic molecules for photodynamic therapy and photothermal therapy

As a worldwide major public health problem, cancer is one of the leading causes of death. Effective treatment of cancer is an important challenge. Therefore, photodynamic therapy (PDT) and photothermal therapy (PTT) have been widely applied as anti-tumour strategies due to their high-performance and limited side effects. Inspired by natural supramolecular architectures, such as cytochromes and photosystems, the hierarchical supramolecular assembly of small organic molecules has been developed for their use as photosensitizers or photothermal agents for PDT and PTT, respectively. In this manuscript, we will summarize the recent progress of PDT and PTT based on the assembly of small organic molecules.

Self-assembled natural small molecule diterpene acids with favorable anticancer activity and biosafety for synergistically enhanced antitumor chemotherapy

Natural biocompatible materials such as self-assembled natural small molecule products (NSMP) with anticancer activity are of increasing interest for synergistic biomedical applications. Herein, we discovered and developed four new self-assembled tricyclic diterpene acids NSMP with favorable anticancer activity for synergistic and safe antitumor chemotherapy, including dehydroabietic acid, 15-hydroxy-dehydroabietic acid, abietic acid, and 12-hydroxyabietic acid. The self-assembled performance and mechanism of these four compounds with different morphologies were explored in detail by molecular dynamics simulation, and revealed the coplanarity and orderliness of molecular arrangements which are speculated to be responsible for the self-assembly into spheres or rods. The screened and optimized abietic acid (AA) was chosen to prepare the synergistic antitumor drug AA-PTX NPs by co-administration with paclitaxel through multiple hydrogen bonds. The resulting nanodrugs were internalized into cells through a lysosome acidification uptake pathway. The improved water-solubility, significantly enhanced in vitro cytotoxicity, and excellent biosafety, lead to a highly efficient and safe in vivo anticancer efficacy of 81.2% inhibition rate with only three doses. This work provides new insights to explore the self-assembly behavior of small molecules and broadens the types of self-assembled active NSMP, providing a promising perspective for the fabrication of active NSMP mediated medical agents for multiple synergistic therapies.

Carrier-Free Triterpene Prodrugs with Glutathione Response and Biosafety for Synergistically Enhanced Photochemotherapy

Carrier-free pure drug self-assembled nanosystems have been proposed as a promising strategy for synergetic anticancer therapy. Herein, we purposefully designed and synthesized disulfide-modified glutathione (GSH)-responsive natural pentacyclic triterpene betulinic acid (BA) with better biodegradability and biocompatibility to construct carrier-free photosensitive prodrugs BA-S-S/Ce6 NPs for synergistically enhanced and biosafe photochemotherapy. The molecular dynamics simulation elucidates the possible coassembly mechanism that the coplanar arrangement of BA-S-S dimeric may be primarily responsible for the formation of a long lamella-like or spherical morphology. The density functional theory calculations demonstrate that the reduced energy gap (ΔEST) of Ce6 facilitates the improved singlet oxygen generation of BA-S-S/Ce6 nanoparticles (NPs). The assembled prodrugs exhibited remarkable GSH-responsive property and multiple favorable therapeutic features, leading to enhanced synergistic antitumor efficacy without noticeable toxicity. Additionally, evaluation of the antitumor efficacy of another tetracyclic triterpene stigmasterol (ST)-mediated ST-S-S/Ce6 NPs further confirmed the effectiveness of this rational design. This work provides a promising insight for exploring the pure drug self-assembly behavior and construction of GSH-responsive carrier-free triterpenoid prodrugs toward improved multiple combination antitumor therapies.

A directed co-assembly of herbal small molecules into carrier-free nanodrugs for enhanced synergistic antitumor efficacy

Carrier-free nanomedicines without structural modification are attractive for the development of natural small molecules (NSMs) and biomedical applications. Moreover, the combination of NSMs is expected to obtain nanomedicines with high efficacy and low side effects due to their inherent pharmacological activities and health benefits. However, poor water solubility and low bioavailability of NSMs limit their wider biomedical and clinical applications. In this study, we revealed the co-assembly properties of pentacyclic triterpenoids and constructed a series of carrier-free nanodrugs, which are co-assembled nanoparticles (NPs) formed by the combination of two NSMs via a supramolecular assembly strategy. Experimental work and simulation studies were combined to reveal the co-assembly mechanism of non-covalent interactions between NSMs. Not only do co-assembled NPs have rapid cellular uptake ability and passive targeting tumor ability based on the EPR effect, but also their constituent units could arrest the cell cycle at different stages of tumor cells and induce apoptosis, showing synergistic anti-tumor effects (CI < 0.7). Compared with self-assembled NPs and positive control, co-assembled NPs show the strongest therapeutic effect in vivo. Importantly, the co-assembled NPs highlight the unique advantages of NSMs in terms of biosafety and health benefits, and systemic toxicity and histological examination confirm that co-assembled NPs have reliable biosafety, and no side effects and nano toxicity risks were observed.

Bioactive Natural Small Molecule-Tuned Coassembly of Photosensitive Drugs for Highly Efficient Synergistic and Enhanced Type I Photochemotherapy

Self-assembling natural small molecules (NSMs) with favorable anticancer activity are of increasing interest as novel drug delivery platforms without structural modification for biomedical applications. However, a lack of knowledge and practicability of NSMs as drug carriers limited their current biomedical application. Here, via a green and facile supramolecular coassembly strategy, we report and develop a series of carrier-free terpenoid natural small molecule-mediated coassembled photosensitive drugs for enhanced and synergistic chemo/photodynamic therapy. After screening 17 terpenoid NSMs, we identified 11 compounds that could form coassembled NSMs-Ce6 NPs with regulatable drug sizes. Analysis of the representative betulonic acid (BC)-mediated nano-coassemblies (BC-Ce6 NPs) reveals the high efficiency of the coassembly strategy and highlights the tremendous potential of NSMs as novel drug delivery platforms. Through molecular dynamics simulation and theoretical calculations, we elucidate the mystery of the coassembly process, indicating that the linear coplanar arrangement of BC dimeric units is primarily responsible for the formation of rod-like or spherical morphology. Meanwhile, we demonstrated that the reduced energy gap between the singlet and triplet excited states (ΔE_ST) facilitates efficient reactive oxygen species generation by promoting ·OH generation via a type I photoreaction mechanism. The assembled nanodrugs exhibit multiple favorable therapeutic features, ensuring a remarkably enhanced, synergistic, and secure combinatorial anticancer efficacy of 93.6% with highly efficient tumor ablation. This work not only expands the possibility of natural biodegradable materials for wide biological applications but also provides a new perspective for the construction of NSM-mediated nano-coassemblies for precision therapy.

Paclitaxel and betulonic acid synergistically enhance antitumor efficacy by forming co-assembled nanoparticles

The side effects and low bioavailability of paclitaxel (PTX) limit its clinical application. The formation of self-assembled nanomedicines without structural modification is attractive for biomedical applications. Here, we constructed a supramolecular co-assembled nanoparticles (NPs), which is formed by betulonic acid (BTA) and PTX mainly through hydrogen bond interaction and hydrophobic interaction. It not only has the characteristics of NPs but also the activity of natural small molecules (NSMs). The results of in vitro and in vivo experiments showed that BTA-PTX NPs showed excellent synergistic enhancement of anti-tumor efficacy, because BTA and PTX have different anti-tumor mechanisms. What's more, BTA-PTX NPs showed excellent biosafety and low toxicity, because BTA has impressive biological activity and biosafety. This work provides an effective and simple method to construct high efficiency and minimize side effects of NPs, which provides more possibilities for the application of NSMs in drug delivery.

Nanomedicine-Cum-Carrier by Co-Assembly of Natural Small Products for Synergistic Enhanced Antitumor with Tissues Protective Actions

The application of natural small products with self-assembly characteristics in a drug-delivery system is attractive for biomedical applications because of its inherent biological safety and pharmacological activity, and there is no complex structural modification process. However, drug carriers with pharmacological effects have not been developed enough. Here, we report a pure natural nanomedicine-cum-carrier (NMC) drug delivery system. The NMC is formed by the direct co-assembly of two small molecular natural compounds through noncovalent interaction, and a molecular dynamics model for predicting the co-assembly of two small molecular compounds was established. The representative co-assembled NMC (oleanolic acid and glycyrrhetinic acid) not only shows excellent stability, high drug loading, and sustained release characteristics but also the co-assembled NMC formed by two small molecular compounds has a synergistic antitumor effect (CI < 0.7). After drug loading, the antitumor effect is further improved. In addition, this NMC highlights the unique advantages of active natural products in biosafety and health benefits. Compared with free drugs, it can reduce the liver damage caused by chemotherapy drugs through upregulating key antioxidant pathways. Compared to nonpharmacologically active drug delivery systems, it can reduce the risk of nanotoxicity. Taken together, this co-assembly drug-carrier system overcomes the shortcomings that pharmacologically active compounds cannot be directly applied, enhances the pharmacological activity of bioactive drug carriers, improves the antitumor efficacy, and slows down the side effects induced by chemotherapy drugs and the additional toxicity caused by long-term use of non-bioactive nanocarriers.

Strategy of Fusion Covalent Organic Frameworks and Molecularly Imprinted Polymers: A Surprising Effect in Recognition and Loading of Cyanidin-3-O-glucoside

Seven magnetic covalent organic framework molecularly imprinted polymers with magnetic responsiveness, large specific surface area, and molecular recognition ability were successfully synthesized, suitable for the separation of cyanidin-3-O-glucoside from complex samples. Using a room-temperature synthesis strategy, covalent organic frameworks accompanied by imprinted sites were formed in one step on the functionalized magnetic nanoparticles with 1,6-hexanediamine. The composite materials were easy to prepare and showed high adsorption capacity (127 mg g^-1) together with favorable adsorption selectivity for cyanidin-3-O-glucoside over other flavonoids and phenolic acids. Magnetic covalent organic framework molecularly imprinted polymers exhibited good stability in 10 adsorption-desorption cycles. This work established a new method of extracting and separating high-purity anthocyanins and even unstable natural compounds.

Green Layer-by-Layer Assembly of Porphyrin/G-Quadruplex-Based Near-Infrared Nanocomposite Photosensitizer with High Biocompatibility and Bioavailability

A simple and green layer-by-layer assembly strategy is developed for the preparation of a highly bioavailable nanocomposite photosensitizer by assembling near-infrared (NIR) light-sensitive porphyrin/G-quadruplex complexes on the surface of a highly biocompatible nanoparticle that is prepared via Zn²⁺-assisted coordination self-assembly of an amphiphilic amino acid. After being efficiently delivered to the target site and internalized into tumor cells via enhanced permeability and retention effect and interactions between aptamers and tumor markers, the as-prepared nanoassembly can be directly used as an NIR light-responsive photosensitizer for tumor photodynamic therapy (PDT) since the porphyrin/G-quadruplex complexes are exposed on the nanoassembly surface and kept in an active state. It can also disassemble under the synergistic stimuli of an acidic pH environment and overexpressed glutathione, leasing more efficient porphyrin/G-quadruplex composite photosensitizers while reducing the interference caused by glutathione-dependent ¹O₂ consumption. Since the nanoassembly can work no matter if it is disassembled or not, the compulsory requirement for in vivo photosensitizer release is eliminated, thus resulting in the great improvement of the bioavailability of the photosensitizer. The PDT applications of the nanoassembly were well demonstrated in both in vitro cell and in vivo animal experiments.

A highly atom-economical bioactive nanocarrier for synergistically enhanced antitumor with reduced liver injury

The drug-cum-carrier-type delivery system makes up for conventional nanocarriers that have no therapeutic efficacy and health benefits.