Ultrasound-Enhanced Delivery of Doxorubicin-Loaded Nanodiamonds from Pullulan-all-trans-Retinal Nanoparticles for Effective Cancer Therapy

Recent breakthroughs in graphene quantum dot-enhanced sonodynamic and photodynamic therapy

Water-soluble graphene quantum dots (GQDs) have recently exhibited considerable potential for diverse biomedical applications owing to their exceptional optical and chemical properties. However, the pronounced heterogeneity in the composition, size, and morphology of GQDs poses challenges for a comprehensive understanding of the intricate correlation between their structural attributes and functional properties. This variability also introduces complexities in scaling the production processes and addressing safety considerations. Light and sound have firmly established their role in clinical applications as pivotal energy sources for minimally invasive therapeutic interventions. Given the limited penetration depth of light, photodynamic therapy (PDT) predominantly targets superficial conditions such as dermatological disorders, head and neck malignancies, ocular ailments, and early-stage esophageal cancer. Conversely, ultrasound-based sonodynamic therapy (SDT) capitalizes on its superior ability to propagate and focus ultrasound within biological tissues, enabling a diverse range of therapeutic applications, including the management of gliomas, breast cancer, hematological tumors, and modulation of the blood-brain barrier (BBB). Considering the advancements in theranostic and precision therapies, reevaluating these conventional energy sources and their associated sensitizers is imperative. This review introduces three prevalent treatment modalities that harness light and sound stimuli: PDT, SDT, and a synergistic approach that integrates PDT and SDT. This study delineated the therapeutic dynamics and contemporary designs of sensitizers tailored to these modalities. By exploring the historical context of the field and elucidating the latest design strategies, this review underscores the pivotal role of GQDs in propelling the evolution of PDT and SDT. This aspires to stimulate researchers to develop "multimodal" therapies integrating both light and sound stimuli.

Fluorescent Nanocarbons: From Synthesis and Structure to Cancer Imaging and Therapy

Nanocarbons are emerging at the forefront of nanoscience, with diverse carbon nanoforms emerging over the past two decades. Early cancer diagnosis and therapy, driven by advanced chemistry techniques, play a pivotal role in mitigating mortality rates associated with cancer. Nanocarbons, with an attractive combination of well-defined architectures, biocompatibility, and nanoscale dimension, offer an incredibly versatile platform for cancer imaging and therapy. This paper aims to review the underlying principles regarding the controllable synthesis, fluorescence origins, cellular toxicity, and surface functionalization routes of several classes of nanocarbons: carbon nanodots, nanodiamonds, carbon nanoonions, and carbon nanohorns. This review also highlights recent breakthroughs regarding the green synthesis of different nanocarbons from renewable sources. It also presents a comprehensive and unified overview of the latest cancer-related applications of nanocarbons and how they can be designed to interface with biological systems and work as cancer diagnostics and therapeutic tools. The commercial status for large-scale manufacturing of nanocarbons is also presented. Finally, it proposes future research opportunities aimed at engendering modifiable and high-performance nanocarbons for emerging applications across medical industries. This work is envisioned as a cornerstone to guide interdisciplinary teams in crafting fluorescent nanocarbons with tailored attributes that can revolutionize cancer diagnostics and therapy.

LIFU/MMP-2 dual-responsive release of repurposed drug disulfiram from nanodroplets for inhibiting vasculogenic mimicry and lung metastasis in triple-negative breast cancer

BACKGROUND

Vasculogenic mimicry (VM), when microvascular channels are formed by cancer cells independent of endothelial cells, often occurs in deep hypoxic areas of tumors and contributes to the aggressiveness and metastasis of triple-negative breast cancer (TNBC) cells. However, well-developed VM inhibitors exhibit inadequate efficacy due to their low drug utilization rate and limited deep penetration. Thus, a cost-effective VM inhibition strategy needs to be designed for TNBC treatment.

RESULTS

Herein, we designed a low-intensity focused ultrasound (LIFU) and matrix metalloproteinase-2 (MMP-2) dual-responsive nanoplatform termed PFP@PDM-PEG for the cost-effective and efficient utilization of the drug disulfiram (DSF) as a VM inhibitor. The PFP@PDM-PEG nanodroplets effectively penetrated tumors and exhibited substantial accumulation facilitated by PEG deshielding in a LIFU-mediated and MMP-2-sensitive manner. Furthermore, upon exposure to LIFU irradiation, DSF was released controllably under ultrasound imaging guidance. This secure and controllable dual-response DSF delivery platform reduced VM formation by inhibiting COL1/pro-MMP-2 activity, thereby significantly inhibiting tumor progression and metastasis.

CONCLUSIONS

Considering the safety of the raw materials, controlled treatment process, and reliable repurposing of DSF, this dual-responsive nanoplatform represents a novel and effective VM-based therapeutic strategy for TNBC in clinical settings.

Unlocking the power of sugar: carbohydrate ligands as key players in nanotherapeutic-assisted targeted cancer therapy

Cancer cells need as much as 40-times more sugar than their normal cell counterparts. This sugar demand is attained by the excessive expression of inimitable transporters on the surface of cancer cells, driven by their voracious appetite for carbohydrates. Nanotechnological advances drive research utilizing ligand-directed therapeutics and diverse carbohydrate analogs. The precise delivery of these therapeutic cargos not only mitigates toxicity associated with chemotherapy but also reduces the grim toll of mortality and morbidity among patients. This in-depth review explores the potential of these ligands in advanced cancer treatment using nanoparticles. It offers a broader perspective beyond the usual ways we deliver drugs, potentially changing the way we fight cancer.

Enhancing drug penetration in solid tumors via nanomedicine: Evaluation models, strategies and perspectives

Effective tumor treatment depends on optimizing drug penetration and accumulation in tumor tissue while minimizing systemic toxicity. Nanomedicine has emerged as a key solution that addresses the rapid clearance of free drugs, but achieving deep drug penetration into solid tumors remains elusive. This review discusses various strategies to enhance drug penetration, including manipulation of the tumor microenvironment, exploitation of both external and internal stimuli, pioneering nanocarrier surface engineering, and development of innovative tactics for active tumor penetration. One outstanding strategy is organelle-affinitive transfer, which exploits the unique properties of specific tumor cell organelles and heralds a potentially transformative approach to active transcellular transfer for deep tumor penetration. Rigorous models are essential to evaluate the efficacy of these strategies. The patient-derived xenograft (PDX) model is gaining traction as a bridge between laboratory discovery and clinical application. However, the journey from bench to bedside for nanomedicines is fraught with challenges. Future efforts should prioritize deepening our understanding of nanoparticle-tumor interactions, re-evaluating the EPR effect, and exploring novel nanoparticle transport mechanisms.

pH-Sensitive nanodiamond co-delivery of retinal and doxorubicin boosts breast cancer chemotherapy

Herein for the first time we take the advantage of nanodiamonds (NDs) to covalently immobilize all-trans retinal (NPA) by an imine bond, allowing pH-mediated drug release. DOX is then physically adsorbed onto NPA to form an NPA@D co-loaded double drug in the sodium citrate medium, which is also susceptible to pH-triggered DOX dissociation. The cytotoxicity results showed that NPA@D could markedly inhibit the growth of DOX-sensitive MCF-7 cells in a synergetic way compared to the NP@D system of single-loaded DOX, while NPA basically showed no cytotoxicity and weak inhibition of migration. In addition, NPA@D can overcome the drug resistance of MCF-7/ADR cells, indicating that this nanodrug could evade the pumping of DOX by drug-resistant cells, but free DOX is nearly ineffective against these cells. More importantly, the fluorescence imaging of tumor-bearing mice in vivo and ex vivo demonstrated that the NPA@D was mainly accumulated in the tumor site rather than any other organ by intraperitoneal injection after 24 h, in which the fluorescence intensity of NPA@D was 19 times that of the free DOX, suggesting that a far reduced off-target effect and side effects would be expected. Therefore, this work presents a new paradigm for improving chemotherapy and reversing drug resistance using the ND platform for co-delivery of DOX and ATR.

Next-Generation Nanomedicine Approaches for the Management of Retinal Diseases

Retinal diseases are one of the leading causes of blindness globally. The mainstay treatments for these blinding diseases are laser photocoagulation, vitrectomy, and repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF) or steroids. Unfortunately, these therapies are associated with ocular complications like inflammation, elevated intraocular pressure, retinal detachment, endophthalmitis, and vitreous hemorrhage. Recent advances in nanomedicine seek to curtail these limitations, overcoming ocular barriers by developing non-invasive or minimally invasive delivery modalities. These modalities include delivering therapeutics to specific cellular targets in the retina, providing sustained delivery of drugs to avoid repeated intravitreal injections, and acting as a scaffold for neural tissue regeneration. These next-generation nanomedicine approaches could potentially revolutionize the treatment landscape of retinal diseases. This review describes the availability and limitations of current treatment strategies and highlights insights into the advancement of future approaches using next-generation nanomedicines to manage retinal diseases.

Pullulan in pharmaceutical and cosmeceutical formulations: A review

Pullulan, an α-glucan polysaccharide, is colorless, odorless, non-toxic, non-carcinogenic, highly biocompatible, edible and biodegradable in nature. The long chains of glucopyranose rings in pullulan structure are linked together by α-(1 → 4) and α-(1 → 6) glycosidic linkages. The occurrence of both glycosidic linkages in the pullulan structure contributes to its distinctive properties. The unique structure of pullulan makes it a potent candidate for both pharmaceutical and cosmeceutical applications. In pharmaceuticals, it can be used as a drug carrier and in various dosage formulations. It has been widely used in drug targeting, implants, ocular dosage forms, topical formulations, oral dosage forms, and oral liquid formulations, etc. Pullulan can be used as a potential carrier of active ingredients and their site-specific delivery to skin layers for cosmeceutical applications. It has been extensively used in cosmeceutical formulations like creams, shampoo, lotions, sunscreen, facial packs, etc. The current review highlights applications of pullulan in pharmaceutical and cosmeceutical applications.

Synthesis of Multi-Stimuli Responsive Fe3O4 Coated with Diamonds Nanocomposite for Magnetic Assisted Chemo-Photothermal Therapy

Nanodiamonds with magnetic resonance imaging (MRI) and targeted drug delivery to exert combined effects for biomedical applications have been considered to be an urgent challenge. Herein, a novel bio-nanoarchitectonics (Fe₃O₄@NDs) with simultaneous imaging and therapeutic capacities was fabricated by covalently conjugating nanodiamonds (NDs) with Fe₃O₄. Fe₃O₄@NDs exhibited better biocompatibility and excellent photothermal stability with superb photothermal conversion performance (37.2%). Fe₃O₄@NDs has high doxorubicin (DOX) loading capacity (193 mg/g) with pH and NIR-responsive release characteristics. Fe₃O₄@NDs loading DOX showed a combined chemo-photothermal inhibitory effect on the tumor cells. Enhanced T₂-weighted MRI contrast toward the tumor, with the assistance of a magnetic field, convinced the Fe₃O₄@NDs gathered in the tumor more efficiently and could be used for MRI-based cancer diagnosis. Our results revealed an effective strategy to achieve a stimuli-sensitive nanoplatform for multifunctional theranostics by the combined action.

Dendrimer-Functionalized Nanodiamonds as Safe and Efficient Drug Carriers for Cancer Therapy: Nucleus Penetrating Nanoparticles

Nanodiamonds (NDs) are increasingly being assessed as potential candidates for drug delivery in cancer cells and they hold great promise in overcoming the side effects of traditional chemotherapeutics. In the current work, carboxylic acid functionalized nanodiamonds (ND-COOH) were covalently modified with poly(amidoamine) dendrimer (PAMAM) to form amine-terminated nanodiamonds (NP). Unlike ND-COOH, the chemically modified nanodiamond platform NP revealed a pH-independent aqueous dispersion stability, enhancing its potential as an effective carrier. Physical encapsulation of poorly water soluble cabazitaxel (CTX) drug on NP formed ND-PAMAM-CTX (NPC) nanoconjugates and substantially reduced the size of CTX from micrometer to nanometer. CTX was localized within the pores of nanoparticle aggregates and the cavities of the PAMAM dendrimer, thus facilitating the loaded drug's controlled and sustained release. NPC's cumulative CTX release efficiency was determined to be ∼95% at pH 4 after 96 h. A high cellular uptake of NPC both within the cytoplasm and nucleus of U87 cells is confirmed, accounting for a reduced IC₅₀ value (1 nM). Both the cell cycle and Western blot analyses confirmed enhanced cell death and suppressed tubulin protein expression in NPC-treated cells. A significantly high inhibition to cell division with early apoptosis and reduced metastasis demonstrates the effective loading of CTX dosages on the nanocarrier. The present work highlights the potential of a newly designed nanocarrier NP as an efficient nanocargo for cellular delivery applications and may provide future insights to treat one of the most aggressive tumors in neuro-oncological research, glioblastoma multiforme (GBM).

Recent Progress in Nanostructured Smart Drug Delivery Systems for Cancer Therapy: A Review

Traditional treatment approaches for cancer involve intravenous chemotherapy or other forms of drug delivery. These therapeutic measures suffer from several limitations such as nonspecific targeting, poor biodistribution, and buildup of drug resistances. However, significant technological advancements have been made in terms of superior modes of drug delivery over the last few decades. Technical capability in analyzing the molecular mechanisms of tumor biology, nanotechnology─particularly the development of biocompatible nanoparticles, surface modification techniques, microelectronics, and material sciences─has increased. As a result, a significant number of nanostructured carriers that can deliver drugs to specific cancerous sites with high efficiency have been developed. This particular maneuver that enables the introduction of a therapeutic nanostructured substance in the body by controlling the rate, time, and place is defined as the nanostructured drug delivery system (NDDS). Because of their versatility and ability to incorporate features such as specific targeting, water solubility, stability, biocompatibility, degradability, and ability to reverse drug resistance, they have attracted the interest of the scientific community, in general, and nanotechnologists as well as biomedical scientists. To keep pace with the rapid advancement of nanotechnology, specific technical aspects of the recent NDDSs and their prospects need to be reported coherently. To address these ongoing issues, this review article provides an overview of different NDDSs such as lipids, polymers, and inorganic nanoparticles. In addition, this review also reports the challenges of current NDDSs and points out the prospective research directions of these nanocarriers. From our focused review, we conclude that still now the most advanced and potent field of application for NDDSs is lipid-based, while other significantly potential fields include polymer-based and inorganic NDDSs. However, despite the promises, challenges remain in practical implementations of such NDDSs in terms of dosage and stability, and caution should be exercised regarding biocompatibility of materials. Considering these aspects objectively, this review on NDDSs will be particularly of interest for small-to-large scale industrial researchers and academicians with expertise in drug delivery, cancer research, and nanotechnology.

Toward Quantitative Bio-sensing with Nitrogen-Vacancy Center in Diamond

The long-dreamed-of capability of monitoring the molecular machinery in living systems has not been realized yet, mainly due to the technical limitations of current sensing technologies. However, recently emerging quantum sensors are showing great promise for molecular detection and imaging. One of such sensing qubits is the nitrogen-vacancy (NV) center, a photoluminescent impurity in a diamond lattice with unique room-temperature optical and spin properties. This atomic-sized quantum emitter has the ability to quantitatively measure nanoscale electromagnetic fields via optical means at ambient conditions. Moreover, the unlimited photostability of NV centers, combined with the excellent diamond biocompatibility and the possibility of diamond nanoparticles internalization into the living cells, makes NV-based sensors one of the most promising and versatile platforms for various life-science applications. In this review, we will summarize the latest developments of NV-based quantum sensing with a focus on biomedical applications, including measurements of magnetic biomaterials, intracellular temperature, localized physiological species, action potentials, and electronic and nuclear spins. We will also outline the main unresolved challenges and provide future perspectives of many promising aspects of NV-based bio-sensing.

Glutathione-Activated NO-/ROS-Generation Nanoparticles to Modulate the Tumor Hypoxic Microenvironment for Enhancing the Effect of HIFU-Combined Chemotherapy

The combination of high-intensity focused ultrasound (HIFU) and chemotherapy has promising potential in the synergistic treatment of various types of solid tumors. However, the clinical efficacy of HIFU in combination chemotherapy is often impeded by the pre-existing hypoxia tumor microenvironment-induced multidrug resistance (MDR). Therefore, it is imperative for HIFU combined with chemotherapy to overcome MDR by improving the tumor hypoxic microenvironment. Hence, we developed highly stable nanoparticles (P@BDOX/β-lapachone-NO-NPs) with intracellular nitric oxide (NO)- and reactive oxygen species (ROS)-generating capabilities at the tumor site to relieve the hypoxic tumor microenvironment in solid tumors. Doxorubicin prodrug (boronate-DOX, BDOX) and β-lapachone were concurrently loaded onto actively targeted pH (low) insertion peptides (pHLIPs)-poly(ethylene glycol) and nitrated gluconic acid copolymers. Our results showed that the ability of P@BDOX/β-lapachone-NO-NPs to generate NO and ROS simultaneously is vital for the sensitization of hypoxic solid tumors for chemotherapy, as evidenced by the suppression of tumor cells and tissues (in vitro and in the nude mice model). Thus, this combined therapy holds considerable potential in the management of hypoxic solid tumors.

Nanomaterials for cancer therapy: current progress and perspectives

Cancer is a disease with complex pathological process. Current chemotherapy faces problems such as lack of specificity, cytotoxicity, induction of multi-drug resistance and stem-like cells growth. Nanomaterials are materials in the nanorange 1–100 nm which possess unique optical, magnetic, and electrical properties. Nanomaterials used in cancer therapy can be classified into several main categories. Targeting cancer cells, tumor microenvironment, and immune system, these nanomaterials have been modified for a wide range of cancer therapies to overcome toxicity and lack of specificity, enhance drug capacity as well as bioavailability. Although the number of studies has been increasing, the number of approved nano-drugs has not increased much over the years. To better improve clinical translation, further research is needed for targeted drug delivery by nano-carriers to reduce toxicity, enhance permeability and retention effects, and minimize the shielding effect of protein corona. This review summarizes novel nanomaterials fabricated in research and clinical use, discusses current limitations and obstacles that hinder the translation from research to clinical use, and provides suggestions for more efficient adoption of nanomaterials in cancer therapy.

Multicomponent-assembled nanodiamond hybrids for targeted and imaging guided triple-negative breast cancer therapy via a ternary collaborative strategy

Uniting combinational strategies has been confirmed to be a robust choice for high-performance cancer treatment due to their abilities to overcome tumor heterogeneity and complexity. However, the development of a simple, effective, and multifunctional theranostics nanoplatform still remains a challenge. In this study, we integrated multicomponent hyaluronic acid (HA), protamine (PS), nanodiamonds (NDs), curcumin (Cur), and IR780 into a single nanoplatform (denoted as HPNDIC) based on the combination of hydrophobic and electrostatic noncovalent interactions for dual-modal fluorescence/photoacoustic imaging guided ternary collaborative Cur/photothermal/photodynamic combination therapy of triple-negative breast cancer (TNBC). A two-step coordination assembly strategy was utilized to realize this purpose. In the first step, PS was utilized to modify the NDs clusters to form positively charged PS@NDs (PND) and the simultaneous encapsulation of the natural small-molecule drug Cur and the photosensitive small-molecule IR780 (PNDIC). Second, HA was adsorbed onto the outer surface of the PNDIC through charge complexation for endowing a tumor-targeting ability (HPNDIC). The resulting HPNDIC had a uniform size, high drug-loading ability, and excellent colloidal stability. It was found that under the near-infrared irradiation condition, IR780 could be triggered to exhibit both PTT/PDT dual-pattern therapy effects, leading to an enhanced therapy efficiency of Cur both in vitro and in vivo with good biocompatibility. Due to the intrinsic imaging property of IR780, the biodistribution and accumulation behavior of HPNDIC in vivo could be monitored by dual-modal fluorescence/photoacoustic imaging. Taken together, our current work demonstrated the assembly of a NDs-based multicomponent theranostic platform for dual-modal fluorescence/photoacoustic imaging guided triple-collaborative Cur/photothermal/photodynamic against TNBC.

Nanodiamonds for bioapplications, recent developments

The world of biomedical research is in constant evolution, requiring more and more conditions and norms through pre-clinic and clinic studies. Nanodiamonds (NDs) with exceptional optical, thermal and mechanical properties emerged on the global scientific scene and recently gained more attention in biomedicine and bioanalysis fields. Many problematics have been deliberated to better understand their in vitro and in vivo efficiency and compatibility. Light was shed on their synthesis, modification and purification steps, as well as particle size and surface properties in order to find the most suitable operating conditions. In this review, we present the latest advances of NDs use in bioapplications. A large variety of subjects including anticancer and antimicrobial systems, wound healing and tissue engineering management tools, but also bioimaging and labeling probes are tackled. The key information resulting from these recent works were evidenced to make an overview of the potential features of NDs, with a special look on emerging therapeutic and diagnosis combinations.

Pullulan based stimuli responsive and sub cellular targeted nanoplatforms for biomedical application: Synthesis, nanoformulations and toxicological perspective

With growing interest in polymers of natural origin, innumerable polysaccharides have gained attention for their biomedical application. Pullulan, one of the FDA approved nutraceuticals, possesses multiple unique properties which make them highly advantageous for biomedical applications. This present review encompasses the sources, production, properties and applications of pullulan. It highlights various pullulan based stimuli-responsive systems (temperature, pH, ultrasound, magnetic), subcellular targeted systems (mitochondria, Golgi apparatus/endoplasmic reticulum, lysosome, endosome), lipid-vesicular systems (solid-lipid nanoparticles, liposomes), polymeric nanofibres, micelles, inorganic (SPIONs, gold and silver nanoparticles), carbon-based nanoplatforms (carbon nanotubes, fullerenes, nanodiamonds) and quantum dots. This article also gives insight into different biomedical, therapeutic and diagnostic applications of pullulan viz., imaging, tumor targeting, stem cell therapy, gene therapy, vaccine delivery, cosmetic applications, protein delivery, tissue engineering, photodynamic therapy and chaperone-like activities. The review also includes the toxicological profile of pullulan which is helpful for the development of suitable delivery systems for clinical applications.

Fluorescent nanoparticles with ultralow chromophore loading for long-term tumor-targeted imaging

Recently, organic dyes with aggregation-induced emission (AIE) have attracted much attention in bioimaging and diagnostics. Relatively, the application of traditional dyes has diminished because of aggregation-caused quenching (ACQ). In this work, we compare the imaging ability of nanoparticle formulations of these two kinds of dyes. Boron dipyrromethene (BODIPY) was chosen as a representative of the ACQ dyes, and an aggregation-induced emission (AIE) dye BPMT was used for comparison. BODIPY and BPMT were entrapped into PEG_5k-PLA_10k to form BODIPY-loaded NPs (BNPs) and BPMT-loaded NPs (ANPs), respectively. In vivo and ex vivo imaging demonstrated that BNP1 with ultralow BODIPY load (0.07%) can effectively accumulate in tumor tissues and enable long-term noninvasive imaging. In contrast, ANP4 with high BPMT load (1.6%) has poor bioimaging ability. In general, our work has certain reference significance for the application of ACQ dyes and AIEgens in bioimaging, diagnostics, and theranostics. STATEMENT OF SIGNIFICANCE: In this work, Boron dipyrromethene (BODIPY) was chosen as a representative of ACQ dyes. As a control, (Z)-2-(4'-(9H-carbazol-9-yl)-[1,1'-biphenyl]-4-yl)-3-(7-(4-(bis(4methoxyphenyl)amino) phenyl) benzo[c] [1,2,5] thiadiazol-4-yl) acrylonitrile (BPMT) was selected as an aggregation-induced emission (AIE) dye. BODIPY and BPMT was entrapped into PEG5k-PLA10k to form BODIPY-loaded NPs (BNPs) and BPMT-loaded NPs (ANPs), respectively. In vivo and ex vivo imaging demonstrated that BNP1 with ultralow BODIPY load (0.07%) can effectively accumulate in tumor tissues and realize long-term noninvasive imaging. The weaknesses of ACQ effect can be converted into advantages by skillful use of nanotechnology, which can not only save the cost but also realize high efficiency targeted cancer imaging.

A redox-sensitive core-crosslinked nanosystem combined with ultrasound for enhanced deep penetration of nanodiamonds into tumors

Nanodiamonds (NDs) as drug delivery vehicles are of great significance in anticancer therapy through enhancing drug retention. However, the major barrier to clinical application of NDs is insufficient tumor penetration owing to their strong aggregation and low passive penetration efficiency. Herein, the core-crosslinked pullulan carrier, assembled using the visible light-induced diselenide (Se–Se) bond crosslinking method for encapsulating nanodiamonds-doxorubicin (NDX), is proposed to improve monodispersity. Furthermore, the core-crosslinked diselenide bond provides the nanosystem with redox-responsive capability and improved structural stability in a physiological environment, which prevents premature drug leakage and achieves tumor site-specific controlled release. What's more, ultrasound (US) is utilized to promote nanosystem intratumoral penetration via enlarged tumor vascular endothelium cell gaps. As expected, the nanosystem combined with ultrasound can enhance anti-tumor efficacy with deep penetration and excellent retention performance in a HepG2 xenograft mouse model. This study highlights the ability of the integrated therapeutic paradigm to overcome the limitation of nanodiamonds and the potential for further application in cancer therapy.

A redox-sensitive core-crosslinked nanosystem is developed as a drug vehicle combined with ultrasound for efficient enhanced deep penetration of nanodiamonds into tumors.

Enzyme-Catalytic Self-Triggered Release of Drugs from a Nanosystem for Efficient Delivery to Nuclei of Tumor Cells

Stimulus-responsive drug delivery nanosystems (DDSs) are of great significance in improving cancer therapy for intelligent control over drug release. However, among them, many DDSs are unable to realize rapid and sufficient drug release because most internal stimulants might be consumed during the release process. To address the plight, an abundant supply of stimulants is highly desirable. Herein, a core crosslinked pullulan-di-(4,1-hydroxybenzylene)diselenide nanosystem, which could generate abundant exogenous-stimulant reactive oxygen species (ROS) via tumor-specific NAD(P)H:quinone oxidoreductase-1 (NQO1) catalysis, was constructed by the encapsulation of β-lapachone. The enzyme-catalytic-generated ROS induced self-triggered cascade amplification release of loaded doxorubicin (DOX) in the tumor cells, thus achieving efficient delivery of DOX to the nuclei of tumor cells by breaking the diselenide bond of the nanosystem. As a result, the antitumor effect of this nanosystem was significantly improved in the HepG2 xenograft model. In general, this study offers a new paradigm for utilizing the interaction between the loaded agent and carrier in the tumor cells to obtain self-triggered drug release in the design of DDSs for enhanced cancer therapy.

Polymeric nanoparticles as carrier for targeted and controlled delivery of anticancer agents

In recent decades, many novel methods by using nanoparticles (NPs) have been investigated for diagnosis, drug delivery and treatment of cancer. Accordingly, the potential of NPs as carriers is very significant for the delivery of anticancer drugs, because cancer treatment with NPs has led to the improvement of some of the drug delivery limitations such as low blood circulation time and bioavailability, lack of water solubility, drug adverse effect. In addition, the NPs protect drugs against enzymatic degradation and can lead to the targeted and/or controlled release of the drug. The present review focuses on the potential of NPs that can help the targeted and/or controlled delivery of anticancer agents for cancer therapy.