Carrier-free nanodrugs with efficient drug delivery and release for cancer therapy: From intrinsic physicochemical properties to external modification

Magnetic graphene oxide nanosheets with amidoamine dendronized crosslinks for dual pH and redox-sensitive doxorubicin delivery

Delivering anticancer drugs to the appropriate site within the body poses a critical challenge in cancer treatment with chemotherapeutic agents like doxorubicin (DOX). Magnetic graphene oxide (GO) nanosheets with generation 1 (G1) amidoamine-dendronized crosslinks were developed by coupling cystamine-functionalized GO nanosheets with Fe3O4 nanoparticles modified with primary amine and methyl acrylate. These magnetic GO nanosheets were loaded with DOX to create a dual pH- and redox-responsive delivery system for cancer chemotherapy. The prepared magnetic nanosheets underwent characterization using FTIR, XRD, DLS, VSM, FE-SEM, and TEM. Physical DOX adsorption was evaluated using various isotherms, including Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. The in-vitro release profiles of DOX from the magnetic nanosheets were studied under different pH conditions, with and without glutathione (GSH), and the drug release data were fitted with various kinetic models. Additionally, an MTT assay was employed to assess the compatibility and antitumor activity of DOX-loaded magnetic nanosheets in the HepG2 cell line. The results showed that the maximum drug loading was 13.1% (w/w) at a drug/carrier ratio of 1. Without GSH addition, the maximum drug release after 10 days was only 17.9% and 24.1% at pH 7.4 and 5.3, respectively. However, in the presence of GSH, the maximum drug release reached 51.7% and 64.8% at pH 7.4 and 5.3, respectively. Finally, the research findings suggest that the magnetic nanosheets exhibited pH- and redox-stimuli drug release, high biocompatibility, and superior antitumor activity compared to free DOX.

Synthesis, characterization and anticancer effect of doxorubicin-loaded dual stimuli-responsive smart nanopolymers

Nanopolymers represent a significant group of delivery vehicles for hydrophobic drugs. In particular, dual stimuli-responsive smart polymer nanomaterials might be extremely useful for drug delivery and release. We analyzed the possibility to include the known antitumor drug doxorubicin (DOX), which has antimitotic and antiproliferative effects, in a nanopolymer complex. Thus, doxorubicin-loaded temperature- and pH-sensitive smart nanopolymers (DOX-SNPs) were produced. Characterizations of the synthesized nanostructures were carried out including zeta potential measurements, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The loading capacity of the nanopolymers for DOX was investigated, and encapsulation and release studies were carried out. In a final step, the cytotoxicity of the DOX-nanopolymer complexes against the HeLa cancer cell line at different concentrations and incubation times was studied. The DOX release depended on temperature and pH value of the release medium, with the highest release at pH 6.0 and 41 °C. This effect was similar to that observed for the commercial liposomal formulation of doxorubicin Doxil. The obtained results demonstrated that smart nanopolymers can be efficiently used to create new types of doxorubicin-based drugs.

Dual-Prodrug-Based Hyaluronic Acid Nanoplatform Provides Cascade-Boosted Drug Delivery for Oxidative Stress-Enhanced Chemotherapy

Insufficient drug accumulation in tumors severely limits the antitumor efficiency of hyaluronic acid (HA) nanomedicine in solid tumors due to superficial penetration depth, low cell uptake, and nonspecific drug release. Hence, we constructed a dual NO prodrug (alkynyl-JSK) and doxorubicin prodrug (cis-DOX)-conjugated HA nanoparticle (HA-DOX-JSK NPs), which achieved cascade-boosted drug delivery efficiency based on a relay strategy of NO-mediated deep tumor penetration─HA target CD44 tumor cell uptake─tumor microenvironment (TME)-responsive drug release. The nanoparticle demonstrated sustained and locoregionally GSH/GST-triggered NO release and GSH/pH-responsive DOX release in the tumor. The released NO first mediated collagen degradation, causing deep tumor penetration of nanoparticles in the dense extracellular matrix. Immediately, HA was relayed to enhance CD44-targeted tumor cell uptake, and then, the nanoparticles were finally triggered by specific TME to release DOX and NO in the deep tumor. Relying on the relayed delivery strategy, a significant improvement of DOX accumulation in tumors was realized. Moreover, NO depleted GSH-induced intracellular reactive oxygen species, enhancing DOX chemotherapy. Based on this strategy, the tumor inhibition rate in breast cancer was up to 87.8% in vivo. The relay drug-delivery HA system would greatly cascade-boost drug accumulation in deep tumors for efficient solid tumor therapy.

Fluorescent Self-Assembled Complexes Based on Glyco-Functionalized G-Quadruplexes as a Targeted Delivery Platform

Targeted delivery systems combined with the stimuli-responsive release of drug molecules hold noteworthy promise for precision medicine, enabling treatments with enhanced effectiveness and reduced adverse effects. An ideal drug delivery platform with versatile targeting moieties, the capability of combinational payloads, and simple preparation is highly desirable. Herein, we developed pH-sensitive fluorescent self-assembled complexes (SACs) of a galactose-functionalized G-quadruplex (G4) and a coumarin carboxamidine derivative as a targeted delivery platform through the nanoprecipitation method. These SACs selectively targeted hepatocellular carcinoma (HepG2) cells in fluorescence imaging after a short incubation and exerted specific anticancer effects in an appropriate dose range. Co-delivery of 1 μM prodrug floxuridine oligomers and 16 μg/mL SACs (minimal hemolytic effect) significantly reduced the cytotoxicity of the nucleoside anticancer drug on normal cells (NIH/3T3), kept up to 70% alive after 72-h incubation, and improved anticancer efficacy compared to SACs alone. This strategy can be extended to ratiometric multidrug delivery through self-assembly for targeted combinational therapy.

Engineered Carrier-Free Nanosystem-Induced In Situ Therapeutic Vaccines for Potent Cancer Immunotherapy

In situ vaccines that can stimulate tumor immune response have emerged as a breakthrough in antitumor therapy. However, the immunosuppressed tumor microenvironment and insufficient infiltration of immune cells lead to ineffective antitumor immunity. Hence, a biomimetic carrier-free nanosystem (BCC) to induce synergistic phototherapy/chemotherapy-driven in situ vaccines was designed. A carrier-free nanosystem was developed using phototherapeutic reagents CyI and celastrol as raw materials. In vitro and in vivo studies have shown that under NIR light irradiation, BCC-mediated photo/chemotherapy not only accelerates the release of drugs to deeper parts of tumors, achieving timing and light-controlled drug delivery to result in cell apoptosis, but also effectively stimulates the antitumor response to induce in situ vaccine, which could invoke long-lasting antitumor immunity to inhibit tumor metastasis and eliminate distant tumor. This therapeutic strategy holds promise for priming robust innate and adaptive immune responses, arresting cancer progression, and inducing tumor dormancy.

Carrier-Free Nanodrugs: From Bench to Bedside

Carrier-free nanodrugs with extraordinary active pharmaceutical ingredient (API) loading (even 100%), avoidable carrier-induced toxicity, and simple synthetic procedures are considered as one of the most promising candidates for disease theranostics. Substantial studies and the commercial success of "carrier-free" nanocrystals have demonstrated their strong clinical potential. However, their practical translations remain challenging and are impeded by unpredictable assembly processes, insufficient delivery efficiency, and an unclear in vivo fate. In this Perspective, we systematically outline the contemporary and emerging carrier-free nanodrugs based on diverse APIs, as well as highlight their opportunities and challenges in clinical translation. Looking ahead, further improvements in design and preparation, drug delivery, in vivo efficacy, and safety of carrier-free nanomedicines are essential to facilitate their translation from the bench to bedside.

Development and Evaluation of Reconstructed Nanovesicles from Turmeric for Multifaceted Obesity Intervention

The escalating prevalence of obesity poses significant health challenges due to its direct association with various diseases. Most existing medications, such as appetite suppressants and fat absorption inhibitors, suffer from limited effectiveness and undesirable side effects. Here, inspired by the versatile metabolic effects of turmeric, we developed a naturally derived nanoformulation of "Reconstructed Turmeric-derived Nanovesicles (Rec-tNVs)" for obesity treatment. Employing quantitative nanoflow cytometry, a four-orders-of-magnitude increase in curcumin content (∼108 molecules per particle) was identified in individual Rec-tNVs compared to their ultracentrifugation-isolated counterparts. Rec-tNVs, featuring highly aggregated curcumin arrangements and other coencapsulated bioactive compounds, demonstrated a dose-dependent lipid-lowering effect in mature 3T3-L1 cells by promoting lipolysis, suppressing lipogenesis, inducing adipocyte browning, and triggering apoptosis after internalization via multiple pathways. In vivo experiments revealed that Rec-tNVs alleviated obesity more effectively than free curcumin and achieved weight reductions of 18.68 and 14.56% through intragastric and subcutaneous delivery, respectively, in high-fat-diet mouse models over a four-week treatment period. These effects were attributed to targeted actions on adipose tissues and systemic impacts on metabolism and gut microbiota composition. Overall, this study underscores the multifaceted antiobesity efficacy of Rec-tNVs, and offers a promising paradigm for developing plant-derived nanovesicle-based therapeutics.

Tailoring biomaterials for vaccine delivery

Biomaterials are substances that can be injected, implanted, or applied to the surface of tissues in biomedical applications and have the ability to interact with biological systems to initiate therapeutic responses. Biomaterial-based vaccine delivery systems possess robust packaging capabilities, enabling sustained and localized drug release at the target site. Throughout the vaccine delivery process, they can contribute to protecting, stabilizing, and guiding the immunogen while also serving as adjuvants to enhance vaccine efficacy. In this article, we provide a comprehensive review of the contributions of biomaterials to the advancement of vaccine development. We begin by categorizing biomaterial types and properties, detailing their reprocessing strategies, and exploring several common delivery systems, such as polymeric nanoparticles, lipid nanoparticles, hydrogels, and microneedles. Additionally, we investigated how the physicochemical properties and delivery routes of biomaterials influence immune responses. Notably, we delve into the design considerations of biomaterials as vaccine adjuvants, showcasing their application in vaccine development for cancer, acquired immunodeficiency syndrome, influenza, corona virus disease 2019 (COVID-19), tuberculosis, malaria, and hepatitis B. Throughout this review, we highlight successful instances where biomaterials have enhanced vaccine efficacy and discuss the limitations and future directions of biomaterials in vaccine delivery and immunotherapy. This review aims to offer researchers a comprehensive understanding of the application of biomaterials in vaccine development and stimulate further progress in related fields.

Carrier-Free Photodynamic Bioregulators Inhibiting Lactic Acid Efflux Combined with Immune Checkpoint Blockade for Triple-Negative Breast Cancer Immunotherapy

Abnormal tumor metabolism creates a complex tumor immune microenvironment that plays a dominant role in the metastasis of triple-negative breast cancer (TNBC). TNBC is insensitive to immune checkpoint blockade (ICB) therapy because of insufficient cytotoxic T lymphocyte (CTL) infiltration and a hyper-lactic acid-suppressive immune microenvironment caused by abnormal glycolysis. Herein, we propose an amplified strategy based on lactic acid regulation to reprogram the immunosuppressive tumor microenvironment (ITM) and combine it with ICB therapy to achieve enhanced antitumor immunotherapy effects. Specifically, we constructed CASN, a carrier-free photodynamic bioregulator, through the self-assembly of the photosensitizer Chlorin e6 and monocarboxylate transporter 1 (MCT1) inhibitor AZD3965. CASN exhibited a uniform structure, good stability, and drug accumulation at the tumor site. CASN-mediated photodynamic therapy following laser irradiation inhibited primary tumor growth and induced immunogenic cell death. Furthermore, CASN reduced lactic acid-mediated regulatory T cell generation and M2 tumor-associated macrophage polarization by blocking MCT1-mediated lactic acid efflux to attenuate immune suppression, inducing the recruitment and activation of CTLs. Ultimately, CASN-mediated immunopotentiation combined with ICB therapy considerably strengthened tumor immunotherapy and effectively inhibited tumor growth and metastasis of TNBC. This synergistic amplification strategy overcomes the limitations of an acidic ITM and presents a potential clinical treatment option for metastatic tumors.

Boron Dipyrromethene-Based Nanotheranostic System for Sonophotoassisted Therapy and Simultaneous Monitoring of Tumor Immune Microenvironment Reprogramming

Therapy-induced modulation of the tumor microenvironment (TME) to overcome the immunosuppressive TME is considered to be an opportunity for cancer treatment. However, monitoring of TME modulation during the therapeutic process to accurately determine immune responses and adjust treatment plans in a timely manner remains to be challenging. Herein, we report a carrier-free nanotheranostic system (CANPs) assembled by two boron dipyrromethene (BODIPY) dyes, a sonophotosensitizer C-BDP, and a nitric oxide (NO) probe amino-BODIPY (A-BDP). CANPs can exert combined sonophototherapeutic effects of C-BDP under ultrasound and light irradiation and simultaneously induce inflammatory TME, as well as emit bright fluorescence via A-BDP by monitoring tumor-associated macrophages (TAMs) repolarization through the released NO in vitro and in vivo. Of note, transforming growth factor-β (TGF-β) could be the key cytokine involved in the sonophototherapy-induced TME reprogramming. By virtue of high physiological stability, good biocompatibility, and effective tumor targetability, CANPs could be a potential nanotheranostic system for the simultaneous induction and detection of TME reprogramming triggered by sonophototherapy.

Supramolecular artificial Nano-AUTACs enable tumor-specific metabolism protein degradation for synergistic immunotherapy

Autophagy-targeting chimera (AUTAC) has emerged as a powerful modality that can selectively degrade tumor-related pathogenic proteins, but its low bioavailability and nonspecific distribution significantly restrict their therapeutic efficacy. Inspired by the guanine structure of AUTAC molecules, we here report supramolecular artificial Nano-AUTACs (GM NPs) engineered by AUTAC molecule GN [an indoleamine 2,3-dioxygenase (IDO) degrader] and nucleoside analog methotrexate (MTX) through supramolecular interactions for tumor-specific protein degradation. Their nanostructures allow for precise localization and delivery into cancer cells, where the intracellular acidic environment can disrupt the supramolecular interactions to release MTX for eradicating tumor cells, modulating tumor-associated macrophages, activating dendritic cells, and inducing autophagy. Specifically, the induced autophagy facilitates the released GN for degrading immunosuppressive IDO to further enhance effector T cell activity and inhibit tumor growth and metastasis. This study offers a unique strategy for building a nanoplatform to advance the field of AUTAC in tumor immunotherapy.

Making the Complicated Simple: A Minimizing Carrier Strategy on Innovative Nanopesticides

The flourishing progress in nanotechnology offers boundless opportunities for agriculture, particularly in the realm of nanopesticides research and development. However, concerns have been raised regarding the human and environmental safety issues stemming from the unrestrained use of non-therapeutic nanomaterials in nanopesticides. It is also important to consider whether the current development strategy of nanopesticides based on nanocarriers can strike a balance between investment and return, and if the complex material composition genuinely improves the efficiency, safety, and circularity of nanopesticides. Herein, we introduced the concept of nanopesticides with minimizing carriers (NMC) prepared through prodrug design and molecular self-assembly emerging as practical tools to address the current limitations, and compared it with nanopesticides employing non-therapeutic nanomaterials as carriers (NNC). We further summarized the current development strategy of NMC and examined potential challenges in its preparation, performance, and production. Overall, we asserted that the development of NMC systems can serve as the innovative driving force catalyzing a green and efficient revolution in nanopesticides, offering a way out of the current predicament.

Aggregation-enhanced photothermal therapy of organic dyes

Photothermal therapy (PTT) represents a groundbreaking approach to targeted disease treatment by harnessing the conversion of light into heat. The efficacy of PTT heavily relies on the capabilities of photothermal agents (PTAs). Among PTAs, those based on organic dyes exhibit notable characteristics such as adjustable light absorption wavelengths, high extinction coefficients, and high compatibility in biological systems. However, a challenge associated with organic dye-based PTAs lies in their efficiency in converting light into heat while maintaining stability. Manipulating dye aggregation is a key aspect in modulating non-radiative decay pathways, aiming to augment heat generation. This review delves into various strategies aimed at improving photothermal performance through constructing aggregation. These strategies including protecting dyes from photodegradation, inhibiting non-photothermal pathways, maintaining space within molecular aggregates, and introducing intermolecular photophysical processes. Overall, this review highlights the precision-driven assembly of organic dyes as a promising frontier in enhancing PTT-related applications. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

Metal-Organic Framework-Based Nanomedicines for Ferroptotic Cancer Therapy

As an iron-dependent, non-apoptosis, regulated cell death (RCD) modality, ferroptosis has gained growing attention for cancer therapy. With the development of nanomaterials in the biomedical field, ferroptotic cancer nanomedicine is extensively investigated. Amongst various nanomaterials, metal-organic frameworks (MOFs) are hybridized porous materials consisting of metal ions or clusters bridged by organic linkers. The superior properties of MOFs, such as high porosity and cargo loading, ease of surface modification, and good biocompatibility, make them appealing in inducing or sensitizing ferroptotic cell death. There are remarkable achievements in the field of MOF-based ferroptosis cancer therapy. However, this topic is not reviewed. This review will introduce the fundamentals of MOF and ferroptosis machinery, summarize the recent progress of MOF-based ferroptotic anticancer drug delivery, discuss the benefits and problems of MOFs as vehicles and sensitizers for cancer ferroptosis, and provide the perspective on future research direction on this promising field.

Long-Acting Ocular Injectables: Are We Looking In The Right Direction?

The complex anatomy and physiological barriers of the eye make delivering ocular therapeutics challenging. Generally, effective drug delivery to the eye is hindered by rapid clearance and limited drug bioavailability. Biomaterial-based approaches have emerged to enhance drug delivery to ocular tissues and overcome existing limitations. In this review, some of the most promising long-acting injectables (LAIs) in ocular drug delivery are explored, focusing on novel design strategies to improve therapeutic outcomes. LAIs are designed to enable sustained therapeutic effects, thereby extending local drug residence time and facilitating controlled and targeted drug delivery. Moreover, LAIs can be engineered to enhance drug targeting and penetration across ocular physiological barriers.

Hypoxia-Responsive Golgi-Targeted Prodrug Assembled with Anthracycline for Improved Antitumor and Antimetastasis Efficacy

Tumor metastasis is an intricate multistep process regulated via various proteins and enzymes modified and secreted by swollen Golgi apparatus in tumor cells. Thus, Golgi complex is considered as an important target for the remedy of metastasis. Currently, Golgi targeting technologies are mostly employed in Golgi-specific fluorescent probes for diagnosis, but their applications in therapy are rarely reported. Herein, we proposed a prodrug (INR) that can target and destroy the Golgi apparatus, which consisted of indomethacin (IMC) as the Golgi targeting moiety and retinoic acid (RA), a Golgi disrupting agent. The linker between IMC and RA was designed as a hypoxia-responsive nitroaromatic structure, which ensured the release of the prototype drugs in the hypoxic tumor microenvironment. Furthermore, INR could be assembled with pirarubicin (THP), an anthracycline, to form a carrier-free nanoparticle (NP) by emulsion-solvent evaporation method. A small amount of mPEG2000-DSPE was added to shield the positive charges and improve the stability of the nanoparticle to obtain PEG-modified nanoparticle (PNP). It was proved that INR released the prototype drugs in tumor cells and hypoxia promoted the release. The Golgi destructive effect of RA in INR was amplified owing to the Golgi targeting ability of IMC, and IMC also inhibited the protumor COX-2/PGE2 signaling. Finally, PNP exhibited excellent curative efficacy on 4T1 primary tumor and its pulmonary and hepatic metastasis. The small molecular therapeutic prodrug targeting Golgi apparatus could be adapted to multifarious drug delivery systems and disease models, which expanded the application of Golgi targeting tactics in disease treatment.

Temperature-mediated diffusion of nanoparticles in semidilute polymer solutions

The temperature is often a critical factor affecting the diffusion of nanoparticles in complex physiological media, but its specific effects are still to be fully understood. Here, we constructed a temperature-regulated model of semidilute polymer solution and experimentally investigated the temperature-mediated diffusion of nanoparticles using the particle tracking method. By examining the ensemble-averaged mean square displacements (MSDs), we found that the MSD grows gradually as the temperature increases while the transition time from sublinear to linear stage in MSD decreases. Meanwhile, the temperature-dependent measured diffusivity of the nanoparticles shows an exponential growth. We revealed that these temperature-mediated changes are determined by the composite effect of the macroscale property of polymer solution and the microscale dynamics of polymer chain as well as nanoparticles. Furthermore, the measured non-Gaussian displacement probability distributions were found to exhibit non-Gaussian fat tails, and the tailed distribution is enhanced as the temperature increases. The non-Gaussianity was calculated and found to vary in the same trend with the tailed distribution, suggesting the occurrence of hopping events. This temperature-mediated non-Gaussian feature validates the recent theory of thermally induced activated hopping. Our results highlight the temperature-mediated changes in diffusive transport of nanoparticles in polymer solutions and may provide the possible strategy to improve drug delivery in physiological media.

Self-engineered binary nanoassembly enabling closed-loop glutathione depletion-amplified tumor ferroptosis

Ferroptosis has emerged as a promising target for anticancer treatment, comprising iron-dependent lipid peroxidation and excessive accumulation of reactive oxygen species. Given that glutathione (GSH) overproduced in tumor cells antagonizes the cellular oxidation system, the reduction of GSH production has been extensively explored to induce ferroptosis. However, reducing GSH production alone is insufficient to trigger an intense lipid peroxidation storm. It is highly desirable to achieve systemic GSH depletion through simultaneous production and consumption intervention. Herein, we propose a bidirectional blockage strategy for closed-loop GSH depletion-amplified tumor ferroptosis. Sorafenib (Sor) and gambogic acid (GA) were elaborately fabricated as a self-engineered carrier-free nanoassembly without any nanocarrier materials. The PEGylated dual-drug nanoassembly enables favorable co-delivery and tumor-specific release of Sor and GA. Notably, a closed-loop GSH depletion is observed as a result of a Sor-induced decrease in GSH production and GA-accelerated GSH consumption in vitro and in vivo. As expected, this uniquely engineered dual-drug nanoassembly demonstrates vigorous antitumor activity in 4T1 breast tumor-bearing mice. This study presents a novel nanotherapeutic modality for ferroptosis-driven cancer treatment.

Zwitterionic dendrimer self-assembled nanodrugs with high drug loading for enhanced anti-tumor ability

Zwitterionic dendrimers have been used to construct many nanomedicines due to their ability to achieve controlled drug release, but their low drug loading content limits their application in nanodrug delivery. To solve this problem, the surface of second generation polypropylimine (G2 PPI) was modified with mercapturized paclitaxel (PTX-SH) and zwitterionic groups to prepare zwitterionic prodrug molecule (PPIMPC), and then zwitterionic dendrimer self-assembled nanodrugs (PPIMPC-DOX micelles) were prepared by incorporating doxorubicin (DOX) into the micelles. The DOX loading and paclitaxel (PTX) loading in PPIMPC-DOX micelles was 6.7% and 26.2%, respectively, and the total drug loading of PPIMPC-DOX was high to 32.9%. In addition, PPIMPC-DOX micelles showed enhanced cytotoxicity due to improved cell uptake of DOX. More importantly, the inhibition rate of tumor was much higher than free DOX. The zwitterionic property and high drug loading of PPIMPC-DOX micelles enhanced anti-tumor ability of chemotherapeutic drugs. The method of preparation of zwitterionic and high drug loading of nanodrugs shows good application prospects in the future.

A redox-responsive nanosystem to suppress chemoresistant lung cancer through targeting STAT3

Cancer stem cells (CSCs) have been demonstrated to be involved in tumor initiation and relapse, and the presence of CSCs in the tumor tissue often leads to therapeutic failure. BBI608 has been identified to eliminate CSCs by inhibiting signal transducer and activator of transcription 3 (STAT3). In this study, we confirm that BBI608 can efficiently suppress the proliferation and migration of non-small cell lung cancer (NSCLC) cells, and specifically kill the stemness-high population in chemoresistant NSCLC cells. To improve its bioavailability and tumor accumulation, BBI608 is successfully encapsulated into redox-responsive PEGylated branched N-(2-hydroxypropyl) methacrylamide (HPMA)-deoxy cholic acid (DA) polymeric nanoparticles (BBI608-SS-NPs). The BBI608-SS-NPs can release the drug in response to high concentrations of intracellular glutathione, and exhibit cytotoxicity against lung cancer cells and CSCs comparable to the free drug BBI608. Furthermore, the BBI608-SS-NPs preferentially accumulate in tumor sites, resulting in a superior anti-tumor efficacy in both cisplatin-resistant cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models of NSCLC. Mechanistic studies demonstrate that BBI608-SS-NPs not only directly inhibit the downstream genes of the STAT3 pathway, but also indirectly inhibit the Wnt pathway. Overall, this stimuli-responsive polymeric nanoformulation of BBI608 shows great potential in the treatment of chemoresistant NSCLC by targeting CSCs.

Micro-syringe chip-guided intratumoral administration of lipid nanoparticles for targeted anticancer therapy

BACKGROUND

Nano-sized drug delivery system has been widely studied as a potential technique to promote tumor-specific delivery of anticancer drugs due to its passive targeting property, but resulting in very restricted improvements in its systemic administration so far. There is a requirement for a different approach that dramatically increases the targeting efficiency of therapeutic agents at targeted tumor tissues.

METHODS

To improve the tumor-specific accumulation of anticancer drugs and minimize their undesirable toxicity to normal tissues, a tumor-implantable micro-syringe chip (MSC) with a drug reservoir is fabricated. As a clinically established delivery system, six liposome nanoparticles (LNPs) with different compositions and surface chemistry are prepared and their physicochemical properties and cellular uptake are examined in vitro. Subsequently, MSC-guided intratumoral administration is studied to identify the most appropriate for the higher tumor targeting efficacy with a uniform intratumoral distribution. For efficient cancer treatment, pro-apoptotic anticancer prodrugs (SMAC-P-FRRG-DOX) are encapsulated to the optimal LNPs (SMAC-P-FRRG-DOX encapsulating LNPs; ApoLNPs), then the ApoLNPs are loaded into the 1 μL-volume drug reservoir of MSC to be delivered intratumorally for 9 h. The tumor accumulation and therapeutic effect of ApoLNPs administered via MSC guidance are evaluated and compared to those of intravenous and intratumoral administration of ApoLNP in 4T1 tumor-bearing mice.

RESULTS

MSC is precisely fabricated to have a 0.5 × 4.5 mm needle and 1 μL-volume drug reservoir to achieve the uniform intratumoral distribution of LNPs in targeted tumor tissues. Six liposome nanoparticles with different compositions of 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (PC), 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (PS), 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)2000] (PEG2000-DSPE) are prepared with average sizes of 100-120 nm and loaded into the 1 μL-volume drug reservoir in MSC. Importantly negatively charged 10 mol% of PS-containing LNPs are very slowly infused into the tumor tissue through the micro-syringe of the MSC over 6 h. The intratumoral targeting efficiency of MSC guidance is 93.5%, effectively assisting the homogeneous diffusion of LNPs throughout the tumor tissue at 3.8- and 2.7-fold higher concentrations compared to the intravenous and intratumoral administrations of LNPs, respectively. Among the six LNP candidates 10 mol% of PS-containing LNPs are finally selected for preparing pro-apoptotic SMAC-P-FRRG-DOX anticancer prodrug-encapsulated LNPs (ApoLNPs) due to their moderate endocytosis rate high tumor accumulation and homogenous intratumoral distribution. The ApoLNPs show a high therapeutic effect specifically to cathepsin B-overexpressing cancer cells with 6.6 μM of IC50 value while its IC50 against normal cells is 230.7 μM. The MSC-guided administration of ApoLNPs efficiently inhibits tumor growth wherein the size of the tumor is 4.7- and 2.2-fold smaller than those treated with saline and intratumoral ApoLNP without MSC, respectively. Moreover, the ApoLNPs remarkably reduce the inhibitor of apoptosis proteins (IAPs) level in tumor tissues confirming their efficacy even in cancers with high drug resistance.

CONCLUSION

The MSC-guided administration of LNPs greatly enhances the therapeutic efficiency of anticancer drugs via the slow diffusion mechanism through micro-syringe to tumor tissues for 6 h, whereas they bypass most hurdles of systemic delivery including hepatic metabolism, rapid renal clearance, and interaction with blood components or other normal tissues, resulting in the minimum toxicity to normal tissues. The negatively charged ApoLNPs with cancer cell-specific pro-apoptotic prodrug (SMAC-P-FRRG-DOX) show the highest tumor-targeting efficacy when they are treated with the MSC guidance, compared to their intravenous or intratumoral administration in 4T1 tumor-bearing mice. The MSC-guided administration of anticancer drug-encapsulated LNPs is expected to be a potent platform system that facilitates overcoming the limitations of systemic drug administration with low delivery efficiency and serious side effects.

Advance Progress in Assembly Mechanisms of Carrier-Free Nanodrugs for Cancer Treatment

Nanocarriers have been widely studied and applied in the field of cancer treatment. However, conventional nanocarriers still suffer from complicated preparation processes, low drug loading, and potential toxicity of carriers themselves. To tackle the hindrance, carrier-free nanodrugs with biological activity have received increasing attention in cancer therapy. Extensive efforts have been made to exploit new self-assembly methods and mechanisms to expand the scope of carrier-free nanodrugs with enhanced therapeutic performance. In this review, we summarize the advanced progress and applications of carrier-free nanodrugs based on different types of assembly mechanisms and strategies, which involved noncovalent interactions, a combination of covalent bonds and noncovalent interactions, and metal ions-coordinated self-assembly. These carrier-free nanodrugs are introduced in detail according to their assembly and antitumor applications. Finally, the prospects and existing challenges of carrier-free nanodrugs in future development and clinical application are discussed. We hope that this comprehensive review will provide new insights into the rational design of more effective carrier-free nanodrug systems and advancing clinical cancer and other diseases (e.g., bacterial infections) infection treatment.

Glycol chitosan stabilized nanomedicine of lapatinib and doxorubicin for the management of metastatic breast tumor

Advanced breast cancer is known to be highly evasive to conventional therapeutic regimes with a 5-year survival rate of less than 30% compared to over 90% for early stages. Although several new approaches are being explored to improve the survival outcome, there is still some room for equipping existing drugs such as lapatinib (LAPA) and doxorubicin (DOX) to fight the systemic disease. LAPA is associated with poorer clinical outcomes in HER2-negative patients. However its ability to also target EGFR has warranted its use in recent clinical trials. Nevertheless, the drug is poorly absorbed post oral administration and possess low aqueous solubility. DOX on the other hand is avoided in vulnerable patients in advanced stages due to its pronounced off-target toxicity. To overcome the pitfalls of the drugs, we have fabricated a nanomedicine co-loaded with LAPA & DOX and stabilized with glycol chitosan, a biocompatible polyelectrolyte. With a loading content of ~ 11.5% and ~ 15% respectively, LAPA and DOX in a single nanomedicine showed synergistic action against triple-negative breast cancer cells in comparison to physically mixed free drugs. The nanomedicine showed a time-dependent association with cancer cells thereon inducing apoptosis leading to ~ 80% cell death. The nanomedicine was found to be acutely safe in healthy Balb/c mice and could negate DOX-induced cardio toxicity. The combination nanomedicine significantly inhibited both the primary 4T1 breast tumor and its spread to the lung, liver, heart, and kidney compared to pristine drug controls. These preliminary data indicate bright prospects for the nanomedicine to be effective against metastatic breast cancer.

Tumor permeable self-delivery nanodrug targeting mitochondria for enhanced chemotherapy

Drug self-delivery systems (DSDSs) have been extensively exploited to enhance drug loading capacity and avoid excipient-related toxicity issues. However, deficient tumor targeting, inferior tumor permeability, prominent burst release, and nonspecific subcellular distribution remain major obstacles. Herein, we reported a ROS-responsive amphiphilic prodrug (CPT-S-NO) synthesized by the conjugation of zwitterionic tertiary amine-oxide (TAO) moiety and hydrophobic camptothecin (CPT) through a thioether linkage, which formed a nanoparticulate DSDS in an aqueous solution. CPT-S-NO, compared with CPT-11 and the water-soluble TAO-modified CPT prodrug (CPT-NO), exhibited prolonged blood circulation, enhanced tumor accumulation, deep tumor penetration, efficient mitochondrial targeting, and ROS-activated drug release to induce mitochondrial dysfunction, corporately conducing to the superior antitumor efficacy in vivo. This TAO decoration strategy promises potential applications in designing multipotent DSDSs for various drugs.

Coordination-Driven Self-Assembly of Biomedicine to Enhance Photodynamic Therapy by Inhibiting Proteasome and Bcl-2

Tumor cells resist oxidative damage and apoptosis by activating defense mechanisms. Herein, a self-delivery biomedicine (designated as BSC) is developed by the self-assembly of Bortezomib (BTZ), Sabutoclax (Sab) and Chlorin e6 (Ce6). Interestingly, BTZ can be coordinated with Sab to promote the assembly of uniform ternary biomedicine through non-covalent intermolecular interactions. Moreover, BTZ as a proteasome inhibitor can prevent tumor cells from scavenging damaged proteins to reduce their oxidative resistance. Sab can downregulate B-cell lymphoma 2 (Bcl-2) to decrease the antiapoptotic protein. Both the proteasome and Bcl-2 inhibitions contribute to increasing cell apoptosis and amplifying photodynamic therapy (PDT) efficacy of Ce6. Encouragingly, carrier-free BSC receives all biological activities of these assembly elements, including photodynamic performance as well as inhibitory capabilities of proteasome and Bcl-2. Besides, BSC has a preferable cellular uptake ability and tumor retention property, which increase the drug delivery efficiency and bioavailability. In vitro and in vivo research demonstrate the superior PDT efficiency of BSC by proteasome and Bcl-2 inhibitions. Of special note, the coordination-driven self-assembly of BSC is pH-responsive, which can be disassembled for controlled drug release upon tumor acidic microenvironment. This study will expand the applicability of self-delivery nanomedicine with sophisticated mechanisms for tumor treatment.

Neutrophil-Mediated Delivery of Nanocrystal Drugs via Photoinduced Inflammation Enhances Cancer Therapy

The efficient delivery of anticancer agents into tumor microenvironments is critical for the success of cancer therapies, but it is a prerequisite that drug carriers should overcome tumor vasculature and possess high drug contents. Here, we found that photoinduced inflammation response caused the migration of neutrophils into tumor microenvironments and neutrophils transported neutrophil-targeted nanoparticles (NPs) across the tumor blood barrier. The results showed that tumor delivery efficiencies of NPs were 5% ID/g, and they were independent of particle sizes (30-200 nm) and their doses (108-1011 NPs). To efficiently deliver anticancer agents into tumors via neutrophils, we fabricated carrier-free paclitaxel nanocrystals (PTX NC). The results showed that neutrophil uptake of PTX NC did not impair neutrophil tumor infiltration, and the sustainable release of PTX from PTX NC in tumors was regulated by paclitaxel protein complexes, thus improving the mouse survival in two preclinical models. Our studies demonstrate that delivery of nanocrystal drugs via neutrophils is a promising method to effectively treat a wide range of cancers, and we have also identified a mechanism of drug release from neutrophils in tumors.

Self-Assembled Carrier-Free Nanodrugs for Starvation Therapy-Amplified Photodynamic Therapy of Cancer

Traditional starvation treatment strategies, which involve glucose oxidase and drug-induced thrombi, often suffer from aggravated tumor hypoxia and have failed to improve antitumor efficacy in combination with oxygen-dependent photodynamic therapy (PDT). Herein, glucose transporter 1 inhibitor genistein (Gen) and photosensitizer chlorin e6 (Ce6) are integrated to construct carrier-free self-assembled nanoparticles defined as GC NPs, for starvation therapy-amplified PDT of tumor. GC NPs with regular morphology and stability are screened out by component adjustment, while the function of each component is preserved. On the one hand, Gen released from GC NPs can cut off tumor glucose uptake by inhibiting the glucose transporter 1 to restrict tumor growth, achieving starvation therapy. On the other hand, they are able to decrease the amount of oxygen consumed by tumor respiration and amplify the therapeutic effect of PDT. In vitro and in vivo experiments verify the excellent synergistic antitumor therapeutic efficacy of GC NPs without any apparent toxicity. Moreover, fluorescence and photoacoustic imaging provide guidance for in vivo PDT, demonstrating the excellent tumor enrichment efficiency of GC NPs. It is believed that this starvation therapy-amplified PDT strategy by carrier-free self-assembled GC NPs holds promising clinical prospects.

pH-triggered dynamic erosive small molecule chlorambucil nano-prodrugs mediate robust oral chemotherapy

Currently, the dynamic erosive small molecule nano-prodrug is of great demand for oral chemotherapy, owing to its precise structure, high drug loading and improved oral bioavailability via overcoming various physiologic barriers in gastrointestinal tract, blood circulation and tumor tissues compared to other oral nanomedicines. Herein, this work highlights the successful development of pH-triggered dynamic erosive small molecule nano-prodrugs based on in vivo significant pH changes, which are synthesized via amide reaction between chlorambucil and star-shaped ortho esters. The precise nano-prodrugs exhibit extraordinarily high drug loading (68.16%), electric neutrality, strong hydrophobicity, and dynamic large-to-small size transition from gastrointestinal pH to tumoral pH. These favorable physicochemical properties can effectively facilitate gastrointestinal absorption, blood circulation stability, tumor accumulation, cellular uptake, and cytotoxicity, therefore achieving high oral relative bioavailability (358.72%) and significant tumor growth inhibition while decreasing side effects. Thus, this work may open a new avenue for robust oral chemotherapy attractive for clinical translation.

Tailor-Made Autophagy Cascade Amplification Polymeric Nanoparticles for Enhanced Tumor Immunotherapy

Chemotherapeutics can induce immunogenic cell death (ICD) by triggering autophagy and mediate antitumor immunotherapy. However, using chemotherapeutics alone can only cause mild cell-protective autophagy and be incapable of inducing sufficient ICD efficacy. The participation of autophagy inducer is competent to enhance autophagy, so the level of ICD is promoted and the effect of antitumor immunotherapy is highly increased. Herein, tailor-made autophagy cascade amplification polymeric nanoparticles STF@AHPPE are constructed to enhance tumor immunotherapy. Arginine (Arg), polyethyleneglycol-polycaprolactone, and epirubicin (EPI) are grafted onto hyaluronic acid (HA) via disulfide bond to form the AHPPE nanoparticles and autophagy inducer STF-62247 (STF) is loaded. When STF@AHPPE nanoparticles target to tumor tissues and efficiently enter into tumor cells with the help of HA and Arg, the high glutathione concentration leads to the cleavage of disulfide bond and the release of EPI and STF. Finally, STF@AHPPE induces violent cytotoxic autophagy and strong ICD efficacy. As compared to AHPPE nanoparticles, STF@AHPPE nanoparticles kill the most tumor cells and show the more obvious ICD efficacy and immune activation ability. This work provides a novel strategy for combining tumor chemo-immunotherapy with autophagy induction.

A Red-Light-Responsive DASA-Polymer with High Water Stability for Controlled Release

Photoresponsive polymers hold vast potential in the realm of drug delivery. Currently, most photoresponsive polymers use ultraviolet (UV) light as the excitation source. However, the limited penetration ability of UV light within biological tissues serves as a significant hindrance to their practical applications. Given the strong penetration ability of red light in biological tissues, the design and preparation of a novel red-light-responsive polymer with high water stability, incorporating the reversible photoswitching compound and donor-acceptor Stenhouse adducts (DASA) for controlled drug release is demonstrated. In aqueous solutions, this polymer exhibits self-assembly into micellar nanovectors (~33 nm hydrodynamic diameter), facilitating the encapsulation of the hydrophobic model drug Nile red (NR) within the micellar core. Upon irradiation by a 660 nm LED light source, photons are absorbed by DASA, leading to the disruption of the hydrophilic-hydrophobic balance of the nanovector and thereby resulting in the release of NR. This newly designed nanovector incorporates red light as a responsive switch, successfully avoiding the problems of photodamage and limited penetration of UV light within biological tissues, thereby further promoting the practical applications of photoresponsive polymer nanomedicines.

Localized chemotherapy approaches and advanced drug delivery strategies: a step forward in the treatment of peritoneal carcinomatosis from ovarian cancer

Peritoneal carcinomatosis (PC) is a common outcome of epithelial ovarian carcinoma and is the leading cause of death for these patients. Tumor location, extent, peculiarities of the microenvironment, and the development of drug resistance are the main challenges that need to be addressed to improve therapeutic outcome. The development of new procedures such as HIPEC (Hyperthermic Intraperitoneal Chemotherapy) and PIPAC (Pressurized Intraperitoneal Aerosol Chemotherapy) have enabled locoregional delivery of chemotherapeutics, while the increasingly efficient design and development of advanced drug delivery micro and nanosystems are helping to promote tumor targeting and penetration and to reduce the side effects associated with systemic chemotherapy administration. The possibility of combining drug-loaded carriers with delivery via HIPEC and PIPAC represents a powerful tool to improve treatment efficacy, and this possibility has recently begun to be explored. This review will discuss the latest advances in the treatment of PC derived from ovarian cancer, with a focus on the potential of PIPAC and nanoparticles in terms of their application to develop new therapeutic strategies and future prospects.

Using chitosan-stabilized, hyaluronic acid-modified selenium nanoparticles to deliver CD44-targeted PLK1 siRNAs for treating bladder cancer

Aims: Achieving an effective biocompatible system for siRNAs delivery to the tumor site remains a significant challenge. Materials & methods: Selenium nanoparticles (SeNPs) modified by chitosan (CS) and hyaluronic acid (HA) were fabricated for PLK1 siRNAs (siPLK1) delivery to the bladder cancer cells. The HA-CS-SeNP@siPLK1 efficacy was evaluated using in vitro and in vivo models. Results: HA-CS-SeNP@siPLK1 was selectively internalized into T24 cells through clathrin-mediated endocytosis. Treatment with HA-CS-SeNP@siPLK1 successfully silenced the PLK1 gene, inhibited cell proliferation and induced cell cycle arrest in vitro. HA-CS-SeNP@siPLK1 could also inhibit tumor growth in vivo without causing systemic toxicity. Conclusion: Our results suggest that HA-CS-SeNPs may provide a good vehicle for delivering siPLK1 to the bladder tumor site.

Platinum-Coordinated Engineered Nanoreactors with O2 Self-Amplificationand On-Demand Cascade Chemo-Drug Synthesis for Self-Reinforcing Hypoxic Oncotherapy

How to efficiently synthesize toxic chemo-drugs in the hypoxia tumor microenvironment still faces a huge challenge. Herein, we have tailored engineered vehicle-free nanoreactors by coordination-driven co-assembly of photosensitizer indocyanine green (ICG), transition metal platinum (Pt), and nontoxic 1,5-dihydroxynaphthalene (DHN) to self-amplify O₂ and cascade chemo-drug synthesis in tumor cells for self-reinforcing hypoxic oncotherapy. Once vehicle-free nanoreactors are internalized into tumor cells, they show a serious instability that results in rapid disassembly and on-demand drug release under the stimuli of acidic lysosome and laser radiation. Notably, the released Pt can efficiently decompose the endogenous hydrogen peroxide (H₂O₂) into O₂ to alleviate tumor hypoxia, which is conducive to enhancing the photodynamic therapy (PDT) efficiency of the released ICG. Complementarily, a large amount of the ¹O₂ generated by PDT can efficiently oxidize the released nontoxic DHN into the highly toxic chemo-drug juglone. Therefore, such vehicle-free nanoreactors can achieve intracellular on-demand cascade chemo-drug synthesis and self-reinforce photo-chemotherapeutic efficacy on the hypoxic tumor. On the whole, such a simple, flexible, efficient, and nontoxic therapeutic strategy will broaden the study of on-demand chemo-drug synthesis and hypoxic oncotherapy.

Nano-biotechnology in tumour and cancerous disease: A perspective review

In recent years, drug manufacturers and researchers have begun to consider the nanobiotechnology approach to improve the drug delivery system for tumour and cancer diseases. In this article, we review current strategies to improve tumour and cancer drug delivery, which mainly focuses on sustaining biocompatibility, biodistribution, and active targeting. The conventional therapy using cornerstone drugs such as fludarabine, cisplatin etoposide, and paclitaxel has its own challenges especially not being able to discriminate between tumour versus normal cells which eventually led to toxicity and side effects in the patients. In contrast to the conventional approach, nanoparticle-based drug delivery provides target-specific delivery and controlled release of the drug, which provides a better therapeutic window for treatment options by focusing on the eradication of diseased cells via active targeting and sparing normal cells via passive targeting. Additionally, treatment of tumours associated with the brain is hampered by the impermeability of the blood-brain barriers to the drugs, which eventually led to poor survival in the patients. Nanoparticle-based therapy offers superior delivery of drugs to the target by breaching the blood-brain barriers. Herein, we provide an overview of the properties of nanoparticles that are crucial for nanotechnology applications. We address the potential future applications of nanobiotechnology targeting specific or desired areas. In particular, the use of nanomaterials, biostructures, and drug delivery methods for the targeted treatment of tumours and cancer are explored.

Self-assembly and self-delivery of the pure nanodrug dihydroartemisinin for tumor therapy and mechanism analysis

Dihydroartemisinin (DHA), a plant-derived natural product, has recently been proven to be an effective therapeutic agent for cancer treatment. Nevertheless, the poor water solubility and low bioavailability of DHA seriously impede its clinical applications. Herein, a simple and green strategy based on the self-assembly of DHA was developed to synthesize carrier-free nanoparticles (NPs). The resulting nanodrug (DHA NPs) was formed by the self-assembly of DHA molecules via hydrogen bonding and hydrophobic interactions. The DHA NPs exhibited a near-spherical morphology with narrow size distribution, favorable drug encapsulation efficiency (>92%), excellent stability, and on-demand drug release behavior. Furthermore, the in vitro and in vivo experiments revealed that the DHA NPs exhibited significantly higher therapeutic efficacy than the DHA equivalent. In addition, we further explored the potential molecular mechanism of the DHA NPs by utilizing RNA-seq technology and western blotting analysis, which demonstrated that the p53 signaling pathway plays a crucial part in the process of inhibiting tumor cell growth and inducing apoptosis. This work not only reveals the rationale for developing pure nanodrugs via the self-assembly of natural small molecules for oncotherapy but also the investigation of the antitumor mechanism and provides novel theoretical support for the clinical usage of DHA.

Carrier-Free H2 O2 Self-Supplier for Amplified Synergistic Tumor Therapy

Chemodynamic therapy (CDT) utilizes Fenton or Fenton-like reactions to convert hydrogen peroxide (H₂ O₂ ) into cytotoxic hydroxyl radicals (•OH) and draws extensive interest in tumor therapy. Nevertheless, high concentrations of glutathione (GSH) and insufficient endogenous H₂ O₂ often cause unsatisfactory therapeutic efficacy. Herein, a GSH-depleting and H₂ O₂ self-providing carrier-free nanomedicine that can efficiently load indocyanine green (ICG), β-lapachone (LAP), and copper ion (Cu²⁺ ) (ICG-Cu²⁺ -LAP, LICN) to mediate synergetic photothermal and chemotherapy in enhanced chemodynamic therapy is designed. The results show that  LICNs successfully enter tumors owing to the enhanced permeability and retention effect. Through the reductive intracellular environment, Cu²⁺ in LICN can react with intracellular GSH, alleviate the antioxidant capacity of tumor tissues, and trigger the release of drugs. When LICN is subjected to near-infrared (NIR) irradiation, enhanced photothermal effect and upregulated expression of NAD(P)H quinone oxidoreductase-1 (NQO1) are observed. Meanwhile, the released LAP not only supports chemotherapy but also catalyzes NQO1 and produces sufficient endogenous H₂ O₂ , thereby increasing the efficiency of Cu⁺ -based Fenton-like reaction. Notably, GSH depletion and H₂ O₂ self-sufficiency generate sufficient •OH and kill tumor cells with high specificity. Overall, the study provides an innovative strategy to self-regulate GSH and H₂ O₂ levels for effective anticancer therapy.

Carrier-Free Immunotherapeutic Nano-Booster with Dual Synergistic Effects Based on Glutaminase Inhibition Combined with Photodynamic Therapy

The immunotherapeutic effect elicited by photodynamic therapy (PDT) is attenuated by tumor defense mechanisms associated with glutamine metabolism, including the metabolic regulation of redox homeostasis and the limitation of the immunosuppressive tumor microenvironment (ITM). Herein, a carrier-free immunotherapeutic nanobooster C9SN with dual synergistic effects was constructed by the self-assembly of glutaminase (GLS) inhibitor compound 968 (C968) and photosensitizer Chlorin e6. C968-mediated GSH deprivation through inhibiting glutamine metabolism prevented PDT-generated reactive oxygen species from being annihilated by GSH, amplifying intracellular oxidative stress, which caused severe cell death and also enhanced the immunogenic cell death (ICD) effect. In addition, genome-wide analysis was carried out using RNA-sequencing to evaluate the changes in cell transcriptome induced by amplifying oxidative stress. Thereafter, neoantigens generated by the enhanced ICD effect promoted the maturation of dendritic cells, thereby recruiting and activating cytotoxic T lymphocytes (CTLs). Meanwhile, C9SN remodeled the ITM by blocking glutamine metabolism to polarize M2-type tumor-associated macrophages (TAMs) into M1-type TAMs, which further recruited and activated the CTLs. Ultimately, this immunotherapeutic nanobooster suppressed primary and distant tumors. This "kill two birds with one stone" strategy would shed light on enhancing tumor immunogenicity and alleviating tumor immunosuppression to improve the immunotherapeutic effect of PDT.

Biomimetic dual-responsive bioengineered nanotheranostics for intracellular cascade-synthesizing chemo-drugs and efficient oncotherapy

Intracellular-synthesized chemo-drugs based on the inherent characteristics of the tumor microenvironment (TME) have been extensively applied in oncotherapy. However, combining other therapeutic strategies to convert nontoxic small molecules into toxic small-molecule chemo-drugs in the TME is still a huge challenge. To address this issue, herein we have developed a biomimetic dual-responsive bioengineered nanotheranostics system via the supramolecular co-assembly of the nontoxic small-molecule 1,5-dihydroxynaphthalene (DHN) and small-molecule photosensitizer indocyanine green (ICG) followed by surface cloaking through red blood cell membranes (RBCs) for intracellular cascade-synthesizing chemo-drugs and efficient oncotherapy. Such nanotheranostics with a suitable diameter, core-shell structure, ultrahigh dual-drug payload rate, and excellent stability can efficiently accumulate in tumor regions and then internalize into tumor cells. Under the dual stimulations of near-infrared laser irradiation and acidic lysosomes, the nanotheranostics system exhibited exceptional instability under heat-primed membrane rupture and pH decrease, thereby achieving rapid disassembly and on-demand drug release. Furthermore, the released ICG can efficiently convert ³O₂ into ¹O₂. After that, the generated ¹O₂ can efficiently oxidize the released nontoxic DHN into the highly toxic chemo-drug juglone, thereby realizing intracellular cascade-synthesizing chemo-drugs and synergistic photodynamic-chemotherapy while reducing detrimental side effects on normal cells or tissues. Overall, it is envisioned that RBC-cloaked nanotheranostics with intracellular cascade-synthesizing chemo-drugs can provide a promising strategy for intracellular chemo-drug synthesis-based oncotherapy.

Multicomponent carrier-free nanodrugs for cancer treatment

Nanocarriers can be used to deliver insoluble anticancer drugs to optimize therapeutic efficacy. However, the potential toxicity of nanocarriers cannot be ignored. Carrier-free nanodrugs are emerging safe drug delivery systems, which are composed of multiple components, such as drugs, bioactive molecules and functional ingredients, avoiding the usage of inert carrier materials and offering advantages that include high drug loading, low toxicity, synergistic therapy, versatile design, and easy surface functionalization. Therefore, how to design multicomponent carrier-free nanodrugs is becoming a priority. In this review, the common strategies for rapid construction of multicomponent carrier-free nanodrugs are briefly explored from the perspective of methodology. The properties of organic-organic, organic-inorganic and inorganic-inorganic multiple carrier-free nanosystems are analyzed according to wettability and in-depth understanding is provided. Further advances in the applications of multiple carrier-free nanodrugs are outlined in anticipation of grasping the intrinsic nature for the design and development of carrier-free nanodrugs.

Enzyme-triggered- and tumor-targeted delivery with tunable, methacrylated poly(ethylene glycols) and hyaluronic acid hybrid nanogels

Enzyme-responsive polymeric-based nanostructures are potential candidates for serving as key materials in targeted drug delivery carriers. However, the major risk in their prolonged application is fast disassembling of the short-lived polymeric-based structures. Another disadvantage is the limited accessibility of the enzyme to the moieties that are located inside the network. Here, we report on a modified environmentally responsive and enzymatically cleavable nanogel carrier that contains a hybrid network. A properly adjusted volume phase transition (VPT) temperature allowed independent shrinking of a) poly(ethylene glycol) methyl ether methacrylate (OEGMA) with di(ethylene glycol) and b) methyl ether methacrylate (MEO2MA) part of the network, and the exposition of hyaluronic acid methacrylate (MeHa) network based carboxylic groups for its targeted action with the cellular based receptors. This effect was substantial after raising temperature in typical hyperthermia-based treatment therapies. Additionally, novel tunable NGs gained an opportunity to store- and to efficient-enzyme-triggered release relatively low but highly therapeutic doses of doxorubicin (DOX) and mitoxantrone (MTX). The controlled enzymatic degradation of NGs could be enhanced by introducing more hyaluronidase enzyme (HAdase), that is usually overexpressed in cancer environments. MTT assay results revealed effective cytotoxic activity of the NGs against the human MCF-7 breast cancer cells, the A278 ovarian cancer cells and also cytocompatibility against the MCF-10A and HOF healthy cells. The obtained tunable, hybrid network NGs might be used as a useful platform for programmed delivery of other pharmaceuticals and diagnostics in therapeutic applications.

Hydrogel-guided strategies to stimulate an effective immune response for vaccine-based cancer immunotherapy

Cancer vaccines have attracted widespread interest in tumor therapy because of the potential to induce an effective antitumor immune response. However, many challenges including weak immunogenicity, off-target effects, and immunosuppressive microenvironments have prevented their broad clinical translation. To overcome these difficulties, effective delivery systems have been designed for cancer vaccines. As carriers in cancer vaccine delivery systems, hydrogels have gained substantial attention because they can encapsulate a variety of antigens/immunomodulators and protect them from degradation. This enables hydrogels to simultaneously reverse immunosuppression and stimulate the immune response. Meanwhile, the controlled release properties of hydrogels allow for precise temporal and spatial release of loads in situ to further enhance the immune response of cancer vaccines. Therefore, this review summarizes the classification of cancer vaccines, highlights the strategies of hydrogel-based cancer vaccines, and provides some insights into the future development of hydrogel-based cancer vaccines.

Untargeted Metabolomic Approach of Curcuma longa to Neurodegenerative Phytocarrier System Based on Silver Nanoparticles

Curcuma is one of the most famous medicinal and tropical aromatic plants. Its health benefits have been appreciated and exploited in traditional Asian medicine since ancient times. Various studies have investigated its complex chemical composition and demonstrated the remarkable therapeutic properties of curcuma's phytoconstituents. Oxidative stress is a decisive driving factor triggering numerous pathologies (neurodegenerative, psychiatric and cardiovascular diseases; diabetes; tumors, etc.). Numerous recent studies have focused on the use of natural compounds and nanomaterials as innovative molecular targeting agents as effective therapeutic strategies. In this study, we report, for the first time, the development of a simple target phytocarrier system that capitalizes on the bioactive properties of curcuma and AgNPs. The complete metabolic profile of curcuma was determined based on gas chromatography-mass spectrometry (GC-MS) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF-MS). A total of 80 metabolites were identified under mass spectra (MS)-positive mode from 10 secondary metabolite categories: terpenoids, amino acids, diarylheptanoids, flavonoids, phenolic acids, steroids, fatty acids, coumarins, alkaloids and miscellaneous. In addition, the biological activity of each class of metabolites was discussed. A comprehensive characterization (FT-IR, UV-Vis, DLS, SEM, TEM, EDS, zeta potential and XRD) was performed to study the morphostructural properties of this new phytocarrier system. Antioxidant activity of the new phytocarrier system was evaluated using a combination of in vitro methods (total phenolic assay, 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and cyclic voltammetric method (Trolox equivalent antioxidant capacity (TEAC) electrochemical assay)). Antioxidants assays showed that the phytocarrier system exhibits superior antioxidant properties to those of its components, i.e., curcuma or citrate-coated-AgNPs. These data confirm the potential to enhance relevant theoretical knowledge in the area of innovative antioxidant agents, with potential application in neurodegenerative therapeutic strategies.

Dietary Antioxidant-Constructed Nanodrugs Can High-Efficiently Kill Cancer Cells while Protecting Noncancer Cells

Despite great advances, the development of cancer drugs that can efficiently kill cancer cells while protecting noncancer cells has not been achieved. By using only dietary antioxidants vitamin C (VC) and (R)-(+)-lipoic acid (LA), we herein develop a nanodrug VC@cLAV featuring the above function. After entering cells, cLAV dissociates into LA and DHLA (dihydrolipoic acid, reduced form of LA) and releases VC and DHA (dehydroascorbate, oxidized form of VC). In cancer cells, the two redox pairs recycle each other and dramatically promote the intracellular reactive oxygen species production to kill cancer cells at low doses comparable to cytotoxic drugs. Oppositely in noncancer cells, the LA/DHLA and VC/DHA pairs exert anti-oxidant action to actively protect the organism by preventing the normal cells from oxidative stress and repairing cells suffering from oxidative stress. When compared with the first-line cytotoxic drug, VC@cLAV displayed superior therapeutic outcomes yet without side effects in diverse tumor models including patient-derived xenograft (PDX). This drug with efficient cancer cell killing and noncancer cell protection represents a new cancer therapy.

Nano-Clays for Cancer Therapy: State-of-the Art and Future Perspectives

To date, cancer continues to be one of the deadliest diseases. Current therapies are often ineffective, leading to the urgency to develop new therapeutic strategies to improve treatments. Conventional chemotherapeutics are characterized by a reduced therapeutic efficacy, as well as them being responsible for important undesirable side effects linked to their non-specific toxicity. In this context, natural nanomaterials such as clayey mineral nanostructures of various shapes (flat, tubular, spherical and fibrous) with adjustable physico-chemical and morphological characteristics are emerging as systems with extraordinary potential for the delivery of different therapeutic agents to tumor sites. Thanks to their submicron size, high specific surface area, high adsorption capacity, chemical inertia and multilayer organization of 0.7 to 1 nm-thick sheets, they have aroused considerable interest among the scientific community as nano systems that are highly biocompatible in cancer therapy. In oncology, the nano-clays usually studied are halloysite, bentonite, laponite, kaolinite, montmorillonite and sepiolite. These are multilayered minerals that can act as nanocarriers (with a drug load generally between 1 and 10% by weight) for improved stabilization, efficient transport and the sustained and controlled release of a wide variety of anticancer agents. In particular, halloysite, montmorillonite and kaolinite are used to improve the dissolution of therapeutic agents and to delay and/or direct their release. In this review, we will examine and expose to the scientific community the extraordinary potential of nano-clays as unique crystalline systems in the treatment of cancer.

Well-Defined pH-Responsive Self-Assembled Block Copolymers for the Effective Codelivery of Doxorubicin and Antisense Oligonucleotide to Breast Cancer Cells

The worldwide steady increase in the number of cancer patients motivates the development of innovative drug delivery systems for combination therapy as an effective clinical modality for cancer treatment. Here, we explored a design concept based on poly(ethylene glycol)-b-poly(2-(dimethylamino)ethyl methacrylate)-b-poly(2-hydroxyethyl methacrylate-formylbenzoic acid) [PEG-b-PDMAEMA-b-P(HEMA-FBA)] for the dual delivery of doxorubicin (DOX) and GTI2040 (an antisense oligonucleotide for ribonucleotide reductase inhibition) to MCF-7 breast cancer cells. PEG-b-PDMAEMA-b-PHEMA, the precursor copolymer, was prepared through chain extensions from a PEG-based macroinitiator via two consecutive atom transfer radical polymerization (ATRP) steps. Then, it was modified at the PHEMA block with 4-formylbenzoic acid (FBA) to install reactive aldehyde moieties. A pH-responsive polymer-drug conjugate (PDC) was obtained by conjugating DOX to the polymer structure via acid-labile imine linkages, and subsequently self-assembled in an aqueous solution to form DOX-loaded self-assembled nanoparticles (DOX-SAN) with a positively charged shell. DOX-SAN condensed readily with negatively charged GTI2040 to form GTI2040/DOX-SAN nanocomplexes. Gel-retardation assay confirmed the affinity between GTI2040 and DOX-SAN. The GTI2040/DOX-SAN nanocomplex at N/P ratio of 30 exhibited a volume-average hydrodynamic size of 136.4 nm and a zeta potential of 21.0 mV. The pH-sensitivity of DOX-SAN was confirmed by the DOX release study based on the significant cumulative DOX release at pH 5.5 relative to pH 7.4. Cellular uptake study demonstrated favorable accumulation of GTI2040/DOX-SAN inside MCF-7 cells compared with free GTI2040/DOX. In vitro cytotoxicity study indicated higher therapeutic efficacy of GTI2040/DOX-SAN relative to DOX-SAN alone because of the downregulation of the R2 protein of ribonucleotide reductase. These outcomes suggest that the self-assembled pH-responsive triblock copolymer is a promising platform for combination therapy, which may be more effective in combating cancer than individual therapies.

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.

Supercritical Fluids and Nanoparticles in Cancer Therapy

Nanoparticles are widely used in the pharmaceutical industry due to their high surface-to-volume ratio. Among the many techniques used to obtain nanoparticles, those based on supercritical fluids ensure reduced dimensions, narrow particle size distributions, and a very low or zero solvent residue in the powders. This review focuses on using supercritical carbon dioxide-based processes to obtain the nanoparticles of compounds used for the treatment or prevention of cancer. The scientific literature papers have been classified into two groups: nanoparticles consisting of a single active principle ingredient (API) and carrier/API nanopowders. Various supercritical carbon dioxide (scCO2) based techniques for obtaining the nanoparticles were considered, along with the operating conditions and advantages and disadvantages of each process.