Multifunctional mesoporous silica-coated graphene nanosheet used for chemo-photothermal synergistic targeted therapy of glioma

Targeting integrins for cancer management using nanotherapeutic approaches: Recent advances and challenges

Integrins are the main cell surface receptors and execute multifaceted functions such as the bidirectional transmission of signals (i.e., inside-out and outside-in) and provide communication between cells and their microenvironments. Integrins are the key regulators of critical biological functions and contribute significantly to the promotion of cancer at almost every stage of disease progression from initial tumor formation to metastasis. Integrin expressions are frequently altered in different cancers, and consequently, several therapeutic strategies targeting integrins have been developed. Furthermore, nanotechnology-based approaches have been devised to overcome the intrinsic limitations of conventional therapies for cancer management, and have been shown to more precise, safer, and highly effective therapeutic tools. Although nanotechnology-based approaches have achieved substantial success for the management of cancer, certain obstacles remain such as inadequate knowledge of nano-bio interactions and the challenges associated with the three stages of clinical trials. This review highlights the different roles of integrins and of integrin-dependent signaling in various cancers and describes the applications of nanotherapeutics targeting integrins. In addition, we discuss RGD-based approaches and challenges posed to cancer management.

InSe Nanosheets for Efficient NIR-II-Responsive Drug Release

Near-infrared-II (NIR-II) biowindow is appealing from the perspectives of larger maximum permissible exposure in comparison with the near-infrared-I biowindow, so the NIR-II-responsive drug-delivery nanoplatform is highly desirable. In this work, two-dimensional InSe nanosheets (InSe NSs) are modified with poly(ethylene glycol) and evaluated as an effective NIR-II-responsive cancer treatment nanoplatform. The InSe NSs synthesized by liquid exfoliation exhibit prominent NIR-II-responsive photothermal conversion efficiency (39.5%) and photothermal stability. Moreover, the InSe NSs have a doxorubicin (DOX) loading capacity as high as 93.6%, along with excellent NIR-II-responsive DOX release characteristic. The superior synergistic chemo/photothermal effects have also been demonstrated by the in vitro experiments in killing cancer cells. In combination with good biocompatibility, the InSe NSs have great potential in therapeutic applications.

Selective photothermal killing of cancer cells using LED-activated nucleus targeting fluorescent carbon dots

The development of effective theranostic probes in cancer therapy is hampered due to issues with selectivity and off-target toxicity. We report the selective LED-photothermal ablation of cervical (HeLa) cancer cells over human dermal fibroblasts (HDF) using a new class of green-emissive fluorescent carbon dots (FCDs). The FCDs can be easily prepared in one pot using cheap and commercial starting materials. Physico-chemical characterization revealed that a surface coating of 2,5-deoxyfructosazine on a robust amorphous core gives rise to the nanomaterial's unique properties. We show that intracellular uptake mostly involves passive mechanisms in combination with intracellular DNA interactions to target the nucleus and that cancer cell selective killing is likely due to an increase in intracellular temperature in combination with ATP depletion, which is not observed upon exposure to either the "naked" core FCDs or the surface components individually. The selectivity of these nanoprobes and the lack of apparent production of toxic metabolic byproducts make these new nanomaterials promising agents in cancer therapy.

Tumor Microenvironment-Activated and Viral-Mimicking Nanodrugs Driven by Molecular Precise Recognition for dNTP Inhibition-Induced Synergistic Cancer Therapy

The medical application of nanotechnology is promising for cancer chemotherapy. However, most of the small-molecule drug assemblies still have such disadvantages as serious drug leakage and nonideal synergistic mechanisms, resulting in undesired therapeutic effect. Both nucleoside analogue-based clofarabine (CA) and methotrexate (MTX) were used as the first-line anticancer medication. However, a single-agent chemotherapy still faced many challenges including low bioavailability and toxic side effects to normal tissues due to nonspecific biodistribution of drugs. Herein, we designed and fabricated novel viral-mimicking and carry-free nanodrugs (CA-MTX NPs) via molecular recognition-driven precise self-assembly between CA and MTX. After introduction of mild acid-responsive PEG-lipid on the surface of CA-MTX NPs, the synthetic nanodrugs with a diameter of ∼150 nm exhibited tumor microenvironment-activated characteristics and self-targeting property. The results suggested that our nanodrugs could achieve superior tumor accumulation and synergistically promote the tumor suppression by collaboratively inhibiting dNTP pools. We foresaw that the well-designed smart nanodrugs delivery system would open a new avenue in synergistic cancer therapeutics.

Graphene-Based Nanomaterials: From Production to Integration With Modern Tools in Neuroscience

Graphene, a two-dimensional carbon crystal, has emerged as a promising material for sensing and modulating neuronal activity in vitro and in vivo. In this review, we provide a primer for how manufacturing processes to produce graphene and graphene oxide result in materials properties that may be tailored for a variety of applications. We further discuss how graphene may be composited with other bio-compatible materials of interest to make novel hybrid complexes with desired characteristics for bio-interfacing. We then highlight graphene's ever-widen utility and unique properties that may in the future be multiplexed for cross-modal modulation or interrogation of neuronal network. As the biological effects of graphene are still an area of active investigation, we discuss recent development, with special focus on how surface coatings and surface properties of graphene are relevant to its biological effects. We discuss studies conducted in both non-murine and murine systems, and emphasize the preclinical aspect of graphene's potential without undermining its tangible clinical implementation.

Polynorepinephrine Nanoparticles: A Novel Photothermal Nanoagent for Chemo-Photothermal Cancer Therapy

Novel photothermal nanoagents (PTNAs) with excellent photothermal performance, smart-responsive property, and biocompatibility are in urgent need for precise chemo-photothermal cancer therapy. Herein, polynorepinephrine nanoparticles (PNE NPs) with a high photothermal conversion efficiency (η) of 808 nm laser (67%), pH/thermal responsibility, and little to no long-term toxicity were synthesized from an endogenic neurotransmitter norepinephrine. Compared to their analogues, polydopamine NPs, a widely used PTNA, PNE NPs exhibited a higher η value (enhanced 1.63-fold) and better cellular uptake efficiency (enhanced 2.57-fold). After modifying with polyethylene glycol (PEG) and loading with doxorubicin (DOX), PNE-PEG@DOX could realize responsive release of DOX under either a cytolysosome pH microenvironment (pH 5.0) or an 808 nm laser irradiation, resulting in an enhanced chemotherapeutic efficacy of DOX. Besides, in vivo combination therapy leads to nearly complete ablation of tumor tissues, while no significant side effects were found in normal tissues. Hence, this intelligent and biocompatible nanoplatform based on PNE NPs holds great potential in promoting the clinic transformation of precise chemo-photothermal cancer therapy.

NIR-II light-modulated thermosensitive hydrogel for light-triggered cisplatin release and repeatable chemo-photothermal therapy

Cisplatin is one of the most effective chemotherapeutic agents, although its clinical use is limited by severe nephrotoxicity. Multifunctional platform for spatiotemporally controlled delivery of cisplatin and multimodal synergistic therapy is highly desirable in antitumor research. Herein, for the first time, an injectable, NIR-II light-modulated and thermosensitive hydrogel is synthesized through supramolecular self-assembly of a conjugated polymer and α-cyclodextrin. This hydrogel intrinsically features NIR responsive characteristics and thermo-responsive properties. The conjugated polymer (poly(N-phenylglycine)) not only tethers the poly(ethylene glycol) chains to enable the hydrogel formation, but also serves as the NIR-absorbing mediators. Accordingly, one particular benefit of this hydrogel is that its building blocks absorb NIR-II light and mediate the photothermal conversion itself, offering the important advantage of a prolonged retention time and thus permitting repeatable treatment upon a single-injection of this hydrogel. Under NIR-II laser irradiation, the localized photothermal effect not only ablates the highly metastatic triple-negative breast cancer (TNBC), but also triggers the on-demand cisplatin release through the thermo-responsive gel-sol transition, thus resulting in enhanced antitumor activity and reduced off-target toxicity. This work not only provides a novel multifunctional platform for NIR-triggered cisplatin release and chemo-photothermal combination therapy, but also presents a promising strategy for the rational design of NIR light-responsive hydrogels for the intervention of highly aggressive cancers.

Stimuli-Responsive Graphene Nanohybrids for Biomedical Applications

Stimuli-responsive materials, also known as smart materials, can change their structure and, consequently, original behavior in response to external or internal stimuli. This is due to the change in the interactions between the various functional groups. Graphene, which is a single layer of carbon atoms with a hexagonal morphology and has excellent physiochemical properties with a high surface area, is frequently used in materials science for various applications. Numerous surface functionalizations are possible for the graphene structure with different functional groups, which can be used to alter the properties of native materials. Graphene-based hybrids exhibit significant improvements in their native properties. Since functionalized graphene contains several reactive groups, the behavior of such hybrid materials can be easily tuned by changing the external conditions, which is very useful in biomedical applications. Enhanced cell proliferation and differentiation of stem cells was reported on the surfaces of graphene-based hybrids with negligible cytotoxicity. In addition, pH or light-induced drug delivery with a controlled release rate was observed for such nanohybrids. Besides, notable improvements in antimicrobial activity were observed for nanohybrids, which demonstrated their potential for biomedical applications. This review describes the physiochemical properties of graphene and graphene-based hybrid materials for stimuli-responsive drug delivery, tissue engineering, and antimicrobial applications.

Aerosol technique-based carbon-encapsulated hollow mesoporous silica nanoparticles for synergistic chemo-photothermal therapy

Near-infrared (NIR)-responsive drug delivery systems have enhanced tumor ablative efficiency through permeation and retention effects. Graphene oxide (GO) has shown great potential both in photothermal therapy and in drug delivery. Thus, in this study, we designed an ambient spark-generated GO, wrapped on topotecan (TPT)-loaded hollow mesoporous silica nanoparticles (HMSN-NH2-TPT-CGO), to function as an efficient platform for pH-dependent sustained release of TPT. HMSN-NH2-TPT-CGO also exhibited a combined chemo-photothermal effect within a single carrier system. This developed system was stable with a uniform particle size (∼190 nm) and was demonstrated to possess a sufficient heat-absorbing capacity to induce tumor cell ablation. We performed the ablation of tumor cells both in vitro and in vivo in combination with photothermal therapy and chemotherapy using the spark-generated functional GO and HMSN. The prepared nanocarriers demonstrated high cellular uptake, apoptosis, and G0/G1 cell cycle arrest. In vivo study using the MDA-MB-231 xenograft model revealed the ultraefficient tumor ablative performance of HMSN-NH2-TPT-CGO compared with that of free TPT, with no toxic effect on vital organs. Altogether, the optimized nanocarriers presented a significant potential to act as a vehicle for cancer treatment. STATEMENT OF SIGNIFICANCE: This is the first study that uses spark-generated graphene oxide nanoflakes to cover the topotecan (TPT)-loaded hollow mesoporous silica nanoparticles (HMSNs) to treat breast cancer. Dense silica was used as a hard template to prepare the HMSNs attributing to a high drug payload. The concentration of Na₂CO₃ was precisely controlled to minimize the silica etching time within 70 min. The use of the nanographene flakes served a dual purpose, first, by acting as a capping agent to prevent the premature release of drug and, second, by serving as a nano heater that significantly ablates the tumor cells. The prepared nanocarriers (NCs) exhibited effective and enhanced in vitro and in vivo apoptosis, as well as significant tumor growth inhibition even after 15 days of treatment time, with no toxic effect to the vital organs. The NCs enhanced in vitro tumor cell killing effects and served as an effective carrier for in vivo tumor regression, thereby highlighting the enormous potential of this system for breast cancer therapy.

Bioceramics: from bone substitutes to nanoparticles for drug delivery

Since the second half of the 20th century, bioceramics are used for bone repair and regeneration. Inspired by bones and teeth, and aimed at mimicking their structure and composition, several artificial bioceramics were developed for biomedical applications. And nowadays, in the 21st century, with the increasing prominence of nanoscience and nanotechnology, certain bioceramics are being used to build smart drug delivery systems, among other applications. This minireview will mainly describe both tendencies through the research work carried out by the research team of María Vallet-Regí.

Interface Engineering of Graphene-Supported Cu Nanoparticles Encapsulated by Mesoporous Silica for Size-Dependent Catalytic Oxidative Coupling of Aromatic Amines

In this study, graphene nanosheet-supported ultrafine Cu nanoparticles (NPs) encapsulated with thin mesoporous silica (Cu-GO@m-SiO₂) materials are fabricated with particle sizes ranging from 60 to 7.8 nm and are systematically investigated for the oxidative coupling of amines to produce biologically and pharmaceutically important imine derivatives. Catalytic activity remarkably increased from 76.5% conversion of benzyl amine for 60 nm NPs to 99.3% conversion and exclusive selectivity of N-benzylidene-1-phenylmethanamine for 7.8 nm NPs. The superior catalytic performance along with the outstanding catalyst stability of newly designed catalysts are attributed to the easy diffusion of organic molecules through the porous channel of mesoporous SiO₂ layers, which not only restricts the restacking of the graphene nanosheets but also prevents the sintering and leaching of metal NPs to an extreme extent through the nanoconfinement effect. Density functional theory calculations were performed to shed light on the reaction mechanism and to give insight into the trend of catalytic activity observed. The computed activation barriers of all elementary steps are very high on terrace Cu(111) sites, which dominate the large-sized Cu NPs, but are significantly lower on step sites, which are presented in higher density on smaller-sized Cu NPs and could explain the higher activity of smaller Cu-GO@m-SiO₂ samples. In particular, the activation barrier for the elementary coupling reaction is reduced from 139 kJ/mol on flat terrace Cu(111) sites to the feasible value of 94 kJ/mol at step sites, demonstrating the crucial role of the step site in facilitating the formation of secondary imine products.

ROS generation and autophagosome accumulation contribute to the DMAMCL-induced inhibition of glioma cell proliferation by regulating the ROS/MAPK signaling pathway and suppressing the Akt/mTOR signaling pathway

Purpose

Chemotherapy after surgery can prolong the survival of patients with gliomas. Dimethylaminomicheliolide (DMAMCL), a novel chemotherapeutic agent, exhibited antitumor properties in acute myeloid leukemia stem cells and showed an increased drug concentration in the brain. This study aims to investigate the specific anticancer activities and mechanisms of DMAMCL in glioma cells.

Materials and methods

In this study, the effects of DMAMCL were evaluated and characterized in U87-MG and U251 glioma cells. Cell viability was assessed by Cell Counting Kit-8. Apoptosis, mitochondrial membrane potential, and intracellular reactive oxygen species (ROS) generation were assessed by fluorescence microscopy. Autophagosome formation was observed with transmission electron microscopy, and the autophagy flux was measured by transfecting cells with mRFP-GFP-LC3 adenoviral vectors. Immunofluorescence and Western blot analyses were used to determine the expression of proteins.

Results

In the present study, treatment with DMAMCL decreased cell viability and induced apoptosis in U87-MG and U251 glioma cells. Additionally, DMAMCL activated autophagy-mediated cell death as evidenced by the formation of autophagosomes, accumulation of LC3B-II, inhibition of autophagy flux, and increase in cell viability after cotreatment with an autophagy inhibitor. Subsequent experiments showed that the DMAMCL-induced apoptosis and autophagy were possibly mediated by ROS generation and Akt/mTOR signaling pathway inhibition. On the other hand, the ROS scavenger N-acetyl-L-cysteine and the Akt activator insulin-like growth factor-1 attenuated the DMAMCL-induced autophagy and cell death.

Conclusion

Our findings revealed that DMAMCL induced apoptosis and autophagic cell death by regulating the ROS/mitogen-activated protein kinase signaling pathway and suppressing the Akt/mTOR signaling pathway in human glioma cells. DMAMCL may be a novel effective anticancer agent, which can target gliomas.

Graphene-Based Smart Platforms for Combined Cancer Therapy

The extensive research of graphene and its derivatives in biomedical applications during the past few years has witnessed its significance in the field of nanomedicine. Starting from simple drug delivery systems, the application of graphene and its derivatives has been extended to a versatile platform of multiple therapeutic modalities, including photothermal therapy, photodynamic therapy, magnetic hyperthermia therapy, and sonodynamic therapy. In addition to monotherapy, graphene-based materials are widely applied in combined therapies for enhanced anticancer activity and reduced side effects. In particular, graphene-based materials are often designed and fabricated as "smart" platforms for stimuli-responsive nanocarriers, whose therapeutic effects can be activated by the tumor microenvironment, such as acidic pH and elevated glutathione (termed as "endogenous stimuli"), or light, magnetic, or ultrasonic stimuli (termed as "exogenous stimuli"). Herein, the recent advances of smart graphene platforms for combined therapy applications are presented, starting with the principle for the design of graphene-based smart platforms in combined therapy applications. Next, recent advances of combined therapies contributed by graphene-based materials, including chemotherapy-based, photothermal-therapy-based, and ultrasound-therapy-based synergistic therapy, are outlined. In addition, current challenges and future prospects regarding this promising field are discussed.

Highly Efficient Vacancy-Driven Photothermal Therapy Mediated by Ultrathin MnO2 Nanosheets

In medical applications, two-dimensional nanomaterials have been widely studied on account of their intriguing properties such as good biocompatibility, stability, and multifunctionality. Herein, an ultrathin MnO₂ nanosheet has been fabricated by a simplistic hydrothermal process. The high photothermal conversion performance (62.4%) can be attributed to the vacancy in the ultrathin MnO₂ nanosheet, as confirmed by the extended X-ray absorption fine structure results and the density functional theory calculation, benefiting photoacoustic imaging-guided cancer therapy. This highly efficient vacancy-induced photothermal therapy has been reported for the first time. As a result, this work demonstrates that this ultrathin MnO₂ nanosheet has a potential to construct a nanosystem for imaging-guided cancer therapy.

Mesoporous Silica Nanomaterials: Versatile Nanocarriers for Cancer Theranostics and Drug and Gene Delivery

Mesoporous silica nanomaterials (MSNs) have made remarkable achievements and are being thought of by researchers as materials that can be used to effect great change in cancer therapies, gene delivery, and drug delivery because of their optically transparent properties, flexible size, functional surface, low toxicity profile, and very good drug loading competence. Mesoporous silica nanoparticles (MSNPs) show a very high loading capacity for therapeutic agents. It is well known that cancer is one of the most severe known medical conditions, characterized by cells that grow and spread rapidly. Thus, curtailing cancer is one of the greatest current challenges for scientists. Nanotechnology is an evolving field of study, encompassing medicine, engineering, and science, and it has evolved over the years with respect to cancer therapy. This review outlines the applications of mesoporous nanomaterials in the field of cancer theranostics, as well as drug and gene delivery. MSNs employed as therapeutic agents, as well as their importance and future prospects in the ensuing generation of cancer theranostics and drug and therapeutic gene delivery, are discussed herein. Thus, the use of mesoporous silica nanomaterials can be seen as using one stone to kill three birds.

NIR-Light- and pH-Responsive Graphene Oxide Hybrid Cyclodextrin-Based Supramolecular Hydrogels

Here, a novel triple-responsive graphene oxide hybrid supramolecular hydrogel based on the electrostatic self-assembly between graphene oxide and a quaternized polymer and the host-guest inclusion between α-cyclodextrins and poly(ethylene glycol) monomethyl ether (mPEG) was constructed. The quaternized polymer was synthesized by quaternization between pH-sensitive poly( N, N-dimethylaminoethyl methacrylate) and bromine end-capped poly(ethylene glycol) monomethyl ether. The supramolecular hydrogels prepared from the host-guest inclusion of poly(ethylene glycol) monomethyl ether and α-cyclodextrins would turn into a mobile sol phase when the temperature was increased above a certain temperature (Tgel-sol). Graphene oxide sheets not only acted as a core material to provide additional cross-linking but also absorbed NIR light and converted NIR light into heat to trigger the gel-sol transition. The constructed graphene oxide hybrid cyclodextrin-based supramolecular hydrogels could respond to NIR light, temperature, and pH, which could be beneficial for controlled release of cargoes and would hold great promise in the field of delivery systems.

β-Cyclodextrin⁻Hyaluronic Acid Polymer Functionalized Magnetic Graphene Oxide Nanocomposites for Targeted Photo-Chemotherapy of Tumor Cells

A multifunctional targeted drug delivery platform (CDHA⁻MGO) has been successfully constructed by grafting β-cyclodextrin⁻hyaluronic acid polymers (CDHA) to Fe₃O₄⁻graphene oxide (MGO). The obtained CDHA⁻MGO nanocomposite has good water-dispersibility, easy magnetic separation, high near-infrared (NIR) photothermal heating, and excellent biocompatibility. The β-cyclodextrin-hyaluronic acid polymers efficaciously enhance the doxorubicin (DOX) loading amount up to 485.43 mg·g-1. Meanwhile, the Fe₃O₄⁻graphene oxide provides a facile photothermal response mechanism to handle the NIR-triggered release of DOX in weak acidic solvent environments. Significantly, the DOX-loaded nanocomposite (DOX@CDHA⁻MGO) has displayed CD44 receptor-mediated active targeting recognition and chemo-photothermal synergistic therapy of hepatoma cells. These findings suggest that the as-prepared drug delivery platform would be of valuable potential for cancer-targeted photo-chemotherapy.

Development of Photo-Activated ROS-Responsive Nanoplatform as a Dual-Functional Drug Carrier in Combinational Chemo-Photodynamic Therapy

Dual functional drug carrier has been a modern strategy in cancer therapy because it is a platform to elicit additive and synergistic effects through combination therapy. Photo-activated external stimuli such as reactive oxygen species (ROS) also ensure adequate drug delivery in a precise temporal and spatial manner. However, current ROS-responsive drug delivery systems usually require tedious synthetic procedures. A facile one-pot approach has been reported herein, to obtain self-assembled polymeric nanocarriers (NCs) for simultaneous paclitaxel (PTX)- and Rose Bengal (RB)-loading to achieve combined chemo-photodynamic therapy and controlled drug release in responsive to a light-induced ROS stimulus. To encapsulate these hydrophobic and hydrophilic drugs, chitosan (CTS), branched polyethylenimine (bPEI) and polyvinyl alcohol (PVA) were selected and fabricated into nanoblended matrices through an oil-in-water emulsion method. The amphiphilic properties of CTS permit simultaneous entrapment of PTX and RB, while the encapsulation efficiency of RB was further improved by increasing the amount of short-chain bPEI. During the one-step assembly process, bovine serum albumin (BSA) was also added to condense the cationic tripolymer mixtures into more stable nanocarriers (BNCs). Hyaluronic acid (HA) was subsequently grafted onto the surface of BNCs through electrostatic interaction, leading to the formation of HA-BSA/CTS/PVA/bPEI-blended nanocarriers (HBNCs) to achieve an efficient prostate-cancer-cell uptake. Importantly, in response to external light irradiation, HBNCs become destabilized owing to the RB-mediated photodynamic action. It allows an on-demand dual-payload release to evoke a simultaneous photodynamic and chemo treatment for cancer cell eradication. Thus, HBNCs present a new promising approach that exhibits a specific vulnerability to RB-induced photosensitization. The consequent dual-cargo release is also expected to successfully combat cancer through a synergistic anti-tumor effect.

Physically-triggered nanosystems based on two-dimensional materials for cancer theranostics

There is an increasing demand to develop effective methods for treating malignant diseases to improve healthcare in our society. Stimuli-responsive nanosystems, which can respond to internal or external stimuli are promising in cancer therapy and diagnosis due to their functionality and versatility. As a newly emerging class of nanomaterials, two-dimensional (2D) nanomaterials have attracted huge interest in many different fields including biomedicine due to their unique physical and chemical properties. In the past decade, stimuli-responsive nanosystems based on 2D nanomaterials have been widely studied, showing promising applications in cancer therapy and diagnosis, including phototherapies, magnetic therapy, drug and gene delivery, and non-invasive imaging. Here, we will focus our attention on the state-of-the-art of physically-triggered nanosystems based on graphene and two-dimensional nanomaterials for cancer therapy and diagnosis. The physical triggers include light, temperature, magnetic and electric fields.

Physicochemical exfoliation of graphene sheets using graphitic carbon nitride

The development of methods for the synthesis of graphene on a large scale at an affordable cost using less toxic materials has attracted significant interest in recent years.

Graphene coated gold nanoparticles: an emerging class of nanoagents for photothermal therapy applications

Optical and photothermal properties of graphene coated gold nanoparticles show that these nanoparticles are more suitable candidates for photothermal therapy applications.

A multifunctional biomimetic hybrid nanocarrier for the controlled delivery of chemotherapy drugs by near-infrared light

We have constructed a biocompatible magnetic nanoparticle-based nanocomposite material by integrating the features of Fe₃O₄ nanoparticles, mesoporous silica and lipid bilayer for the treatment of tumor.

Targeted delivery of reduced graphene oxide nanosheets using multifunctional ultrasound nanobubbles for visualization and enhanced photothermal therapy

Ultrasound molecular imaging as a promising strategy, which involved the use of molecularly targeted contrast agents, combined the advantages of contrast-enhanced ultrasound with the photothermal effect of reduced graphene oxide (rGO).

Methods and results

The heparin sulfate proteoglycan glypican-3 (GPC3) is a potential molecular target for hepatocellular carcinoma (HCC). In this study, we covalently linked biotinylated GPC3 antibody to PEGylated nano-rGO to obtain GPC3-modified rGO-PEG (rGO-GPC3), and then combined rGO-GPC3 with avidinylated nanobubbles (NBs) using biotin-avidin system to prepare NBs-GPC3-rGO with photothermal effect and dispersibility, solubility in physiological environment. The average size of NBs-GPC3-rGO complex was 700.4±52.9 nm due to the polymerization of biotin-avidin system. Scanning electron microscope (SEM) showed NBs-GPC3-rGO attached to human hepatocellular carcinoma HepG2 cell. The ultrasound-targeted nanobubble destruction (UTND) technology make use of the physical energy of ultrasound exposure for the improvement of rGO delivery. Compared with other control groups, the highest nanobubble destruction efficiency of NBs-GPC3-rGO was attributed to the dissection effect of rGO on UTND. This is a positive feedback effect that leads to an increase in the concentration of rGO around the HepG2 cell. So NBs-GPC3-rGO using UTND and near-infrared (NIR) irradiation resulted in cell viability within 24 h, 48 h, 72 h lower than other treatment groups.

Conclusion

This work established NBs-GPC3-rGO as an ultrasonic photothermal agent due to its suitable size, imaging capability, photothermal efficiency for visual photothermal therapy in vitro.

Fabricating polydopamine-coated MoSe2-wrapped hollow mesoporous silica nanoplatform for controlled drug release and chemo-photothermal therapy

BACKGROUND

Integration of several types of therapeutic agents into one nanoplatform to enhance treatment efficacy is being more widely used for cancer therapy.

METHODS

Herein, a biocompatible polydopamine (PDA)-coated MoSe2-wrapped doxorubicin (DOX)-loaded hollow mesoporous silica nanoparticles (HMSNs) nanoplatform (PM@HMSNs-DOX) was fabricated for dual-sensitive drug release and chemo-photothermal therapy for enhancing the therapeutic effects on breast cancer. The HMSNs were obtained by a "structural difference-based selective etching" strategy and served as the drug carrier, exhibiting a high DOX loading capacity of 427 mg/g HMSNs-NH2, and then wrapped with PDA-coated MoSe2 layer to form PM@HMSNs-DOX. Various techniques proved the successful fabrication of the nanocomposites.

RESULTS

The formed PM@HMSNs-DOX nanocomposites exhibited good biocompatibility, good stability, and super-additive photothermal conversion efficiency due to the cooperation of MoSe2 and PDA. Simultaneously, the pH/near-infrared-responsive drug release profile was observed, which could enhance the synergistic therapeutic anticancer effect. The antitumor effects of PM@HMSNs-DOX were evaluated both in vitro and in vivo, demonstrating that the synergistic therapeutic efficacy was significantly superior to any monotherapy. Also, in vivo pharmacokinetics studies showed that PM@HMSNs-DOX had a much longer circulation time than free DOX. In addition, in vitro and in vivo toxicity studies certified that PM@HMSNs are suitable as biocompatible agents.

CONCLUSION

Our nanoplatform loaded with DOX displays pH/near-infrared-induced chemotherapy and excellent photothermal therapy, which hold great potential for cancer treatment.

Metal-Organic Framework as a Microreactor for in Situ Fabrication of Multifunctional Nanocomposites for Photothermal-Chemotherapy of Tumors in Vivo

Metal-organic frameworks (MOFs) have been applied in chemotherapeutic drug loading for cancer treatment, but challenging for cases with large and malignant lesions. To overcome these difficulties, combinational therapies of chemotherapy and photothermal therapy (PTT) with potentially high selectivity and slight aggressiveness have drawn tremendous attention to treat various tumors. However, current MOF-based nanohybrids with photothermal agents involve tedious synthesis processes and heterogeneous structures. Herein, we employ MIL-53 as a microreactor to grow polypyrrole (PPy) nanoparticles in situ for the fabrication of PPy@MIL-53 nanocomposites. Fe³⁺ in MIL-53, as an intrinsic oxidizing agent, can oxidize the pyrrole monomer to generate PPy nanoparticles. The prepared PPy@MIL-53 nanocomposites integrate the intrinsic advantages of MOFs with high drug loading ability and magnetic resonance imaging (MRI) capacity, and PPy nanoparticles with outstanding PTT ability and excellent biocompatibility. The versatile PPy@MIL-53 nanocomposites with multiple functions displayed in vitro and in vivo synergism of photothermal-chemotherapy for cancer, potentially MRI-guided. The proposed MOF microreactor-based synthesis strategy shows a promising prospect in the fabrication of diverse multifunctional nanohybrids for tumor theranostics in vivo.

Mesoporous silica nanoparticles for therapeutic/diagnostic applications

Based on unique intrinsic properties of mesoporous silica nanoparticles (MSNs) such as high surface area, large pore size, good biocompatibility and biodegradability, stable aqueous dispersion, they have received much attention in the recent decades for their applications as a promising platform in the biomedicine field. These porous structures possess a pore size ranging from 2 to 50 nm which make them excellent candidates for various biomedical applications. Herein, at first we described the common approaches of cargo loading and release processes from MSNs. Then, the intracellular uptake, safety and cytotoxicity aspects of MSNs are discussed as well. This review also highlights the most recent advances in the biomedical applications of MSNs, including 1) MSNs-based carriers, 2) MSNs as bioimaging agents, 3) MSNs-based biosensors, 4) MSNs as therapeutic agents (photodynamic therapy), 5) MSN based quantum dots, 6) MSNs as platforms for upconverting nanoparticles, and 6) MSNs in tissue engineering.

Receptor-Targeted Glial Brain Tumor Therapies

Among primary brain tumors, malignant gliomas are notably difficult to manage. The higher-grade tumors represent an unmet need in medicine. There have been extensive efforts to implement receptor-targeted therapeutic approaches directed against gliomas. These approaches include immunotherapies, such as vaccines, adoptive immunotherapy, and passive immunotherapy. Targeted cytotoxic radio energy and pro-drug activation have been designed specifically for brain tumors. The field of targeting through receptors progressed significantly with the discovery of an interleukin 13 receptor alpha 2 (IL-13RA2) as a tumor-associated receptor over-expressed in most patients with glioblastoma (GBM) but not in normal brain. IL-13RA2 has been exploited in novel experimental therapies with very encouraging clinical responses. Other receptors are specifically over-expressed in many patients with GBM, such as EphA2 and EphA3 receptors, among others. These findings are important in view of the heterogeneity of GBM tumors and multiple tumor compartments responsible for tumor progression and resistance to therapies. The combined targeting of multiple receptors in different tumor compartments should be a preferred way to design novel receptor-targeted therapeutic approaches in gliomas.

Application of polydopamine in tumor targeted drug delivery system and its drug release behavior

Inspired by the bionics of marine mussels, polydopamine (PDA), a new polymer with unique physicochemical properties was discovered. Due to its simple preparation, good biocompatibility, unique drug-loading methods, PDA has attracted tremendous attentions in field of drug delivery and imaging, and the combination of chemotherapy and other therapies or diagnostic methods, such as photothermotherapy (PTT), photoacoustic imaging (PAI), magnetic resonance imaging (MRI), etc. As an excellent drug carrier in tumor targeted drug delivery system, the drug release behavior of drug-loaded PDA-based nanoparticles is also an important factor to be considered in the establishment of drug delivery systems. Therefore, the purpose of this review is to provide a comprehensive overview of the various applications of PDA in tumor targeted drug delivery systems and to gain insight into the release behavior of the drug-loaded PDA-based nanocarriers. A sufficient understanding and discussion of these aspects is expected to provide a better way to design more rational and effective PDA-based tumor nano-targeted delivery systems. Apart from this, the prospects for the future application of PDA in this field and some unique insights are listed at the end of the article.

Graphene quantum dots-gated hollow mesoporous carbon nanoplatform for targeting drug delivery and synergistic chemo-photothermal therapy

BACKGROUND

Carbon-based drug delivery systems have attracted great interest because of their excellent photothermal conversion capability and high specific surface area for drug loading. Herein, we report a multifunctional nanoplatform based on hyaluronic acid (HA)-modified and graphene quantum dot (GQD)-gated hollow mesoporous carbon nanoparticle (HMCN) for anticancer drug encapsulation and targeted chemo-photothermal therapy of CD44 receptor-overexpressed cancer cells.

METHODS

In this design, HMCN was not only used as a nanocarrier with high drug loading content to achieve chemotherapy, but also as a near-infrared absorbing agent to realize photothermal therapy. GQDs could not only prevent premature drug release during blood circulation, but also enhance the chemo-photothermal therapeutic efficacy for complete tumor growth suppression. After being modified with HA, the HA-HMCN(DOX)@GQDs could specifically target cancer cells.

RESULTS

As expected, the as-prepared HMCN exhibited high doxorubicin (DOX)-loading capacity of 410 mg/g and excellent light-to-heat conversion property. The DOX was released from HA-HMCN(DOX)@GQDs in a near-infrared laser and pH stimuli-responsive manner, which could enhance the therapeutic effect. In vitro cell biological experimental results confirmed that the nanoplatform possesses excellent biocompatibility, specifically target CD44 receptor-overexpressing human cervical carcinoma HeLa cells, and has remarkable synergistic chemo-photothermal killing capacity. The in vivo therapeutic studies in HeLa xenografts also showed negligible toxicity of HA-HMCN@GQDs and complete inhibition of tumor growth of HA-HMCN(DOX) @GQDs with near-infrared irradiation.

CONCLUSION

The excellent therapeutic effects demonstrated in vitro and in vivo suggested the HMCN-based nanoplatform holds potential for efficient dual-responsive targeting drug delivery and synergistic chemo-photothermal therapy.

Polydopamine-Modified Black Phosphorous Nanocapsule with Enhanced Stability and Photothermal Performance for Tumor Multimodal Treatments

As a novel 2D material, black phosphorus (BP) nanosheets are considered as a promising candidate for drug delivery platform for synergistic chemo/photothermal therapy. However, the intrinsic instability of bare BP poses a challenge in its biomedical applications. To date, some strategies have been employed to prevent BP from rapid ambient degradation. Unfortunately, most of these strategies are not suitable for the drug delivery systems. Here, a simple polydopamine modification method is developed to enhance the stability and photothermal performance of bare BP nanosheets. Then, this nanocapsule is used as a multifunctional codelivery system for the targeted chemo, gene, and photothermal therapy against multidrug-resistant cancer. The enhanced tumor therapy effect is demonstrated by both in vitro and in vivo studies.

Graphene Family Materials in Bone Tissue Regeneration: Perspectives and Challenges

We have witnessed abundant breakthroughs in research on the bio-applications of graphene family materials in current years. Owing to their nanoscale size, large specific surface area, photoluminescence properties, and antibacterial activity, graphene family materials possess huge potential for bone tissue engineering, drug/gene delivery, and biological sensing/imaging applications. In this review, we retrospect recent progress and achievements in graphene research, as well as critically analyze and discuss the bio-safety and feasibility of various biomedical applications of graphene family materials for bone tissue regeneration.

Enhanced Photodynamic Anticancer Activities of Multifunctional Magnetic Nanoparticles (Fe₃O₄) Conjugated with Chlorin e6 and Folic Acid in Prostate and Breast Cancer Cells

Photodynamic therapy (PDT) is a promising alternative to conventional cancer treatment methods. Nonetheless, improvement of in vivo light penetration and cancer cell-targeting efficiency remain major challenges in clinical photodynamic therapy. This study aimed to develop multifunctional magnetic nanoparticles conjugated with a photosensitizer (PS) and cancer-targeting molecules via a simple surface modification process for PDT. To selectively target cancer cells and PDT functionality, core magnetic (Fe₃O₄) nanoparticles were covalently bound with chlorin e6 (Ce6) as a PS and folic acid (FA). When irradiated with a 660-nm long-wavelength light source, the Fe₃O₄-Ce6-FA nanoparticles with good biocompatibility exerted marked anticancer effects via apoptosis, as confirmed by analyzing the translocation of the plasma membrane, nuclear fragmentation, activities of caspase-3/7 in prostate (PC-3) and breast (MCF-7) cancer cells. Ce6, used herein as a PS, is thus more useful for PDT because of its ability to produce a high singlet oxygen quantum yield, which is owed to deep penetration by virtue of its long-wavelength absorption band; however, further in vivo studies are required to verify its biological effects for clinical applications.

A redox-activated theranostic nanoagent: toward multi-mode imaging guided chemo-photothermal therapy

Development of tumor microenvironment responsive and modulating theranostic nano-systems is of great importance for specific and efficient cancer therapy. Herein, we report a redox-sensitive nanoagent combining manganese dioxide (MnO2) and gold nanoshell coated silicon nanoparticles for synergistic chemo-photothermal therapy of hypoxia solid tumors. In highly reducing tumor tissues, the outer MnO2 nanosheet with the loaded drug would be dissociated by intracellular glutathione (GSH), resulting in on-demand drug release, as well as generating Mn2+ ions which provided high contrast magnetic resonance imaging (MRI), and fluorescence imaging (FI) in vitro and in vivo. While upon near-infrared (NIR) light irradiation, the gold nanoshell modulated the hypoxic tumor microenvironment via increasing blood flow, achieving enhanced photothermal therapy (PTT) and chemotherapy. After tail vein injection into tumor-bearing mice and monitoring in real time, the intelligent redox-activated nanoagent exhibited high tumor accumulation and powerful synergistic chemo-photothermal therapy efficiency. The proposed work developed a noninvasive strategy to modulate the tumor microenvironment and enhance the anticancer therapeutic effect. We believe that this single nano-platform exhibits promising potential as a comprehensive theranostic agent to enhance the efficacies of synergistic cancer therapy.

Hyaluronic Acid Layer-By-Layer (LbL) Nanoparticles for Synergistic Chemo-Phototherapy

PURPOSE

The aim of this study was to design hyaluronic acid (HA) layer-by-layer (LbL) nanoparticles, which carried paclitaxel (PTX) and Indocyanine green (ICG) to both tumor cells and tumor associated cells to achieve synergistic chemo-photothermal therapeutic effect.

METHODS

The LbL-engineered nanoparticles (PDIH) were prepared by dopamine self-polymerization on PTX nanocrystal to form thin, surface-adherent polydopamine (PDA) films, which subsequently absorbed ICG and HA. The tumor cell and tumor associated cell targeting and antitumor efficacy of PDIH were investigated both in vitro an in vivo using 4 T1 murine mammary cancer cell lines and mice bearing orthotopic 4 T1 breast tumor.

RESULTS

PDIH presented a long-rod shape in TEM and showed enhanced photothermal effect and cytotoxicity upon NIR laser irradiation both in vitro and in vivo. PDIH also displayed high target ability to CD44 overexpressed tumor cells and tumor associated cells mediated by HA. In vivo antitumor study indicated that PDIH therapeutic strategy could achieve remarkable antitumor efficacy.

CONCLUSION

PDIH showed excellent tumor-targeting property and chemo-photothermal therapeutic efficacy.

Mesoporous silica-coated gold nanostars with drug payload for combined chemo-photothermal cancer therapy

Combined chemo-photothermal therapy is attracting increasing attention in the treatment of cancers. In this work, PEGylated mesoporous SiO₂-coated gold nanostars (GNS@mSiO₂-PEG) were synthesised without using the cytotoxic surfactant cetyltrimethylammonium bromide as the template. Mesoporous nanostructures were obtained by poly(vinylpyrrolidone) protection of the outer silica shell and NaOH etching of the inner shell. GNS@mSiO₂-PEG exhibited good dispersity in medium and excellent photothermal effects. Loading capacity for the anticancer drug doxorubicin (DOX) was ∼17.9%, and the drug release profile was pH- and light-responsive. In vitro studies revealed that the as-prepared nanocomposites featured good biocompatibility. Furthermore, the nanocomposites were readily internalised by cancer cells, and a combined chemo-photothermal therapy assay revealed that DOX-loaded GNS@mSiO₂-PEG have a higher therapeutic efficiency than individual therapies, demonstrating suitable synergistic effects.

Multifunctional melanin-like nanoparticles for bone-targeted chemo-photothermal therapy of malignant bone tumors and osteolysis

Malignant bone tumors associated with aggressive osteolysis are currently hard to be cured by the clinical strategies. Nevertheless, nanomedicine might provide a promising therapeutic opportunity. Here, we developed a multifunctional melanin-like nanoparticle for bone-targeted chemo-photothermal treatment of malignant bone tumors. The particle was originally fabricated from alendronate-conjugated polydopamine nanoparticle (PDA-ALN) that exhibited excellent photothermal effect and high affinity to hydroxyapatite. PDA/Fe-ALN significantly enhanced the magnetic resonance contrast of the bone tumors in vivo, suggesting that more PDA-ALN accumulated at the osteolytic bone lesions in the tumors compared with the non-targeting PDA. Chemodrug SN38 was efficiently loaded on PDA-ALN, and the drug release could be triggered by near-infrared irradiation and acidic stimulus. Finally, the combined chemo-photothermal therapy efficiently suppressed the growth of bone tumors and reduced the osteolytic damage of bones at a mild temperature around 43 °C. This study provides an efficient and robust nanotherapeutics for the treatment of malignant bone tumors.

Potential applications of engineered nanoparticles in medicine and biology: an update

Nanotechnology advancements have led to the development of its allied fields, such as nanoparticle synthesis and their applications in the field of biomedicine. Nanotechnology driven innovations have given a hope to the patients as well as physicians in solving the complex medical problems. Nanoparticles with a size ranging from 0.2 to 100 nm are associated with an increased surface to volume ratio. Moreover, the physico-chemical and biological properties of nanoparticles can be modified depending on the applications. Different nanoparticles have been documented with a wide range of applications in various fields of medicine and biology including cancer therapy, drug delivery, tissue engineering, regenerative medicine, biomolecules detection, and also as antimicrobial agents. However, the development of stable and effective nanoparticles requires a profound knowledge on both physico-chemical features of nanomaterials and their intended applications. Further, the health risks associated with the use of engineered nanoparticles needs a serious attention.

Therapeutic mesopore construction on 2D Nb2C MXenes for targeted and enhanced chemo-photothermal cancer therapy in NIR-II biowindow

Two-dimensional (2D) MXenes have emerged as a promising planar theranostic nanoplatform for versatile biomedical applications; but their in vivo behavior and performance has been severely influenced and hindered by a lack of necessary surface chemistry for adequate surface engineering. To solve this critical issue, this work employs versatile sol-gel chemistry for the construction of a unique "therapeutic mesopore" layer onto the surface of 2D niobium carbide (Nb2C) MXene. Methods: The in situ self-assembled mesopore-making agent (cetanecyltrimethylammonium chloride, in this case) was kept within the mesopores for efficient chemotherapy. The abundant surface saline chemistry of mesoporous silica-coated Nb2C MXene was further adopted for stepwise surface engineering including PEGylation and conjugation with cyclic arginine-glycine-aspartic pentapeptide c(RGDyC) for targeted tumor accumulation. Results: 2D Nb2C MXenes were chosen based on their photothermal conversion capability (28.6%) in the near infrared (NIR)-II biowindow (1064 nm) for enhanced photothermal hyperthermia. Systematic in vitro and in vivo assessments demonstrate targeted and enhanced chemotherapy and photothermal hyperthermia of cancer (U87 cancer cell line and corresponding tumor xenograft; inhibition efficiency: 92.37%) in the NIR-II biowindow by these mesopore-coated 2D Nb2C MXenes. Conclusion: This work not only significantly broadens the biomedical applications of 2D Nb2C MXene for enhanced cancer therapy, but also provides an efficient strategy for surface engineering of 2D MXenes to satisfy versatile application requirements.