Graphene-Based Photodynamic Therapy and Overcoming Cancer Resistance Mechanisms: A Comprehensive Review

Photodynamic therapy (PDT) is a non-invasive therapy that has made significant progress in treating different diseases, including cancer, by utilizing new nanotechnology products such as graphene and its derivatives. Graphene-based materials have large surface area and photothermal effects thereby making them suitable candidates for PDT or photo-active drug carriers. The remarkable photophysical properties of graphene derivates facilitate the efficient generation of reactive oxygen species (ROS) upon light irradiation, which destroys cancer cells. Surface functionalization of graphene and its materials can also enhance their biocompatibility and anticancer activity. The paper delves into the distinct roles played by graphene-based materials in PDT such as photosensitizers (PS) and drug carriers while at the same time considers how these materials could be used to circumvent cancer resistance. This will provide readers with an extensive discussion of various pathways contributing to PDT inefficiency. Consequently, this comprehensive review underscores the vital roles that graphene and its derivatives may play in emerging PDT strategies for cancer treatment and other medical purposes. With a better comprehension of the current state of research and the existing challenges, the integration of graphene-based materials in PDT holds great promise for developing targeted, effective, and personalized cancer treatments.

Macromolecular Nano-Assemblies for Enhancing the Effect of Oxygen-Dependent Photodynamic Therapy Against Hypoxic Tumors

In oxygen (O2)-dependent photodynamic therapy (PDT), photosensitizers absorb light energy, which is then transferred to ambient O2 and subsequently generates cytotoxic singlet oxygen (1O2). Therefore, the availability of O2 and the utilization efficiency of generated 1O2 are two significant factors that influence the effectiveness of PDT. However, tumor microenvironments (TMEs) characterized by hypoxia and limited utilization efficiency of 1O2 resulting from its short half-life and short diffusion distance significantly restrict the applicability of PDT for hypoxic tumors. To address these challenges, numerous macromolecular nano-assemblies (MNAs) have been designed to relieve hypoxia, utilize hypoxia or enhance the utilization efficiency of 1O2. Herein, we provide a comprehensive review on recent advancements achieved with MNAs in enhancing the effectiveness of O2-dependent PDT against hypoxic tumors.

Graphene Oxide Nanoparticles and Organoids: A Prospective Advanced Model for Pancreatic Cancer Research

Pancreatic cancer, notorious for its grim 10% five-year survival rate, poses significant clinical challenges, largely due to late-stage diagnosis and limited therapeutic options. This review delves into the generation of organoids, including those derived from resected tissues, biopsies, pluripotent stem cells, and adult stem cells, as well as the advancements in 3D printing. It explores the complexities of the tumor microenvironment, emphasizing culture media, the integration of non-neoplastic cells, and angiogenesis. Additionally, the review examines the multifaceted properties of graphene oxide (GO), such as its mechanical, thermal, electrical, chemical, and optical attributes, and their implications in cancer diagnostics and therapeutics. GO's unique properties facilitate its interaction with tumors, allowing targeted drug delivery and enhanced imaging for early detection and treatment. The integration of GO with 3D cultured organoid systems, particularly in pancreatic cancer research, is critically analyzed, highlighting current limitations and future potential. This innovative approach has the promise to transform personalized medicine, improve drug screening efficiency, and aid biomarker discovery in this aggressive disease. Through this review, we offer a balanced perspective on the advancements and future prospects in pancreatic cancer research, harnessing the potential of organoids and GO.

Graphene oxide nanoarchitectures in cancer therapy: Drug and gene delivery, phototherapy, immunotherapy, and vaccine development

The latest advancements in oncology involves the creation of multifunctional nanostructures. The integration of nanoparticles into the realm of cancer therapy has brought about a transformative shift, revolutionizing the approach to addressing existing challenges and limitations in tumor elimination. This is particularly crucial in combating the emergence of resistance, which has significantly undermined the effectiveness of treatments like chemotherapy and radiotherapy. GO stands as a carbon-derived nanoparticle that is increasingly finding utility across diverse domains, notably in the realm of biomedicine. The utilization of GO nanostructures holds promise in the arena of oncology, enabling precise transportation of drugs and genetic material to targeted sites. GO nanomaterials offer the opportunity to enhance the pharmacokinetic behavior and bioavailability of drugs, with documented instances of these nanocarriers elevating drug accumulation at the tumor location. The GO nanostructures encapsulate genes, shielding them from degradation and facilitating their uptake within cancer cells, thereby promoting efficient gene silencing. The capability of GO to facilitate phototherapy has led to notable advancements in reducing tumor progression. By PDT and PTT combination, GO nanomaterials hold the capacity to diminish tumorigenesis. GO nanomaterials have the potential to trigger both cellular and innate immunity, making them promising contenders for vaccine development. Additionally, types of GO nanoparticles that respond to specific stimuli have been applied in cancer eradication, as well as for the purpose of cancer detection and biomarker diagnosis. Endocytosis serves as the mechanism through which GO nanomaterials are internalized. Given these advantages, the utilization of GO nanomaterials for tumor elimination comes highly recommended.

NI-BODIPY-GO Nanocomposites for Targeted PDT

Three multifunctional targeted NI-BODIPYs (10-12) and GO-(10-12) nanocarriers were fabricated. NI-BODIPYs are designed to facilitate non-covalent interaction with graphene oxide (GO) and target toward cancer cells for specific recognition with glucose moieties while efficiently producing singlet oxygen. We probed detailed characterization, fundamental photophysical/photochemical properties, and interactions with GO of such triplet photosensitizers and nanocarriers. The effect of the formation of nanohybrids with GO on singlet oxygen formation as well as on the efficacies of the molecules in terms of in vitro killing of cancer cells was evaluated with K562 human chronic myelogenous leukemia cells. Amazingly, it was observed that GO exhibited favorable interactions with the NI-BODIPY dyads and promoted the formation of singlet oxygen, while not showing any dark toxicity.

BODIPY-GO nanocomposites decorated with a biocompatible branched ethylene glycol moiety for targeted PDT

The properties of graphene oxide (GO) have received much attention and been applied to the exploration of potential applications in disease-related diagnostics and non-invasive therapy. One application, photodynamic therapy (PDT), involves the killing of cancer cells where singlet oxygen is generated with light irradiation of the appropriate wavelength. In this work, three new BODIPY derivatives (13-15), decorated with carbohydrate moieties for active targeting and branched ethylene glycol for biocompatibility, and their GO based nanocarriers were designed to study the singlet oxygen production and PDT efficiency. First, BODIPYs were prepared, followed by the fabrication of GO layers with BODIPY dyes via a non-covalent method. Detailed characterizations of the materials were carried out with mass spectrometry, FT-IR spectroscopy, ¹H NMR, ¹³C NMR, elemental analysis, Raman spectroscopies, EDX analysis and TEM and AFM microscopies. The efficiency of singlet oxygen generation in organic and water-based solutions was determined by photobleaching with 1,3-diphenylisobenzofuran (DPBF) and 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA), respectively. The results in in vitro PDT analysis against K562 human cancer cells indicate the prepared materials are highly promising in PDT anticancer therapy and the IC₅₀ values of GO loaded BODIPY derivatives bearing heavy atoms, GO-14 and GO-15, were calculated as 40.59 nM and 39.21 nM, respectively.

pH-Responsive Selenium Nanoplatform for Highly Efficient Cancer Starvation Therapy by Atorvastatin Delivery

Recently, starvation-inducing nutrient deprivation has been regarded as a promising strategy for tumor suppression. As a first-line lipid-lowering drug, atorvastatin (ATV) significantly reduces caloric intake, suggesting its potential in starvation therapy for suppressing tumors. Accordingly, we developed a novel starvation therapy agent (HA-Se-ATV) in this study to suppress tumor growth by using hyaluronic acid (HA)-conjugated chitosan polymer-coated nano-selenium (Se) for loading ATV. HA-Se-ATV targets cancer cells, following which it effectively accumulates in the tumor tissue. The HA-Se-ATV nanoplatform was then activated by inducing a weakly acidic tumor microenvironment and subsequently releasing ATV. ATV and Se synergistically downregulate the levels of cellular adenosine triphosphate while inhibiting the expression of thioredoxin reductase 1. Consequently, the starvation-stress reaction of cancer cells is significantly elevated, leading to cancer cell death. Furthermore, the in vivo results indicate that HA-Se-ATV effectively suppresses tumor growth with a low level of toxicity, demonstrating its great potential for clinical translation.

Multifunctional graphene oxide nanoparticles for drug delivery in cancer

Recent advancements in nanotechnology have enabled us to develop sophisticated multifunctional nanoparticles or nanosystems for targeted diagnosis and treatment of several illnesses, including cancers. To effectively treat any solid tumor, the therapy should preferably target just the malignant cells/tissue with minor damage to normal cells/tissues. Graphene oxide (GO) nanoparticles have gained considerable interest owing to their two-dimensional planar structure, chemical/mechanical stability, excellent photosensitivity, superb conductivity, high surface area, and good biocompatibility in cancer therapy. Many compounds have been functionalized on the surface of GO to increase their biological applications and minimize cytotoxicity. The review presents an overview of the physicochemical characteristics, strategies for various modifications, toxicity and biocompatibility of graphene and graphene oxide, current trends in developing GO-based nano constructs as a drug delivery cargo and other biological applications, including chemo-photothermal therapy, chemo-photodynamic therapy, bioimaging, and theragnosis in cancer. Further, the review discusses the challenges and opportunities of GO, GO-based nanomaterials for the said applications. Overall, the review focuses on the therapeutic potential of strategically developed GO nanomedicines and comprehensively discusses their opportunities and challenges in cancer therapy.

AIE-based gold nanostar-berberine dimer nanocomposites for PDT and PTT combination therapy toward breast cancer

We designed and synthesized three new berberine-based compounds, namely, pyridine-2,6-dimethyl-/2,2'-bipyridine-3,3'-dimethyl-tethered berberine dimers BD1 and BD2, and a tetrakis(4-benzyl)ethylene linked berberine tetramer BD4. We identified that the dimer BD2 and tetramer BD4, as well as 1,10-phenanthroline-2,9-dimethyl-linked berberine dimer BD3 previously reported by us, showed remarkable aggregation-induced emission (AIE) properties which endowed them with higher singlet oxygen (¹O₂) production ability than berberine. Of the four compounds, BD3 exhibits the lowest ΔE_ST energy with the highest ¹O₂ generation ability and thus was selected for further construction of AuNSs-BD3@HA (denoted as ABH, AuNSs = gold nanostars; HA = hyaluronic acid). The nanosystem of ABH shows a remarkable therapeutic effect toward breast cancer by combining photodynamic therapy (PDT) from BD3, photothermal therapy (PTT) from AuNSs, and the CD44-targeting capability of HA. The synergistically enhanced PDT and PTT induce superior cancer cell apoptosis/necrosis in vitro and anti-breast cancer activity in vivo. This study provides a new concept for PDT using natural product derivatives and their combination with PTT for efficient treatment of tumors.

Combined Photothermal and Photodynamic Therapy for Cancer Treatment Using a Multifunctional Graphene Oxide

Graphene oxide (GO) is one of the most studied nanomaterials in many fields, including the biomedical field. Most of the nanomaterials developed for drug delivery and phototherapies are based on noncovalent approaches that lead to an unspecific release of physisorbed molecules in complex biological environments. Therefore, preparing covalently functionalized GO using straightforward and versatile methods is highly valuable. Phototherapies, including photothermal therapy (PTT) and photodynamic therapy (PDT), have shown great potential as effective therapeutic approaches against cancer. To overcome the limits of a single method, the combination of PTT and PDT can lead to a combined effect with a higher therapeutic efficiency. In this work, we prepare a folic acid (FA) and chlorin e6 (Ce6) double-functionalized GO for combined targeted PTT/PDT. This conjugate can penetrate rapidly into cancer cells and macrophages. A combined effect of PTT and PDT is observed, leading to a higher killing efficiency toward different types of cells involved in cancer and other diseases. Our work provides a simple protocol to prepare multifunctional platforms for the treatment of various diseases.

Construction of pH-sensitive targeted micelle system co-delivery with curcumin and dasatinib and evaluation of anti-liver cancer

Nanomedicine delivery systems can achieve precise drug delivery and reduce toxic side effects compared with traditional drug delivery methods, but further development is still needed to eliminate obstacles such as multiple drug co-delivery, uncontrolled drug-release, and drug-resistance. Herein, we designed a dual drug-loaded nanosystem (THCD-NPs) that selectively transports and targets tumor cells for the treatment of liver cancer. In this drug delivery system, hyaluronic acid (HA)-conjugated curcumin (Cur) and d-α-tocopherol acid polyethylene glycolsuccinate (TPGS) were used as selective drug-carrying vehicles to deliver dasatinib (DAS) to cancer cells for combined administration. The mean size of the nanoparticles was approximately 66.14 ± 4.02 nm with good in vitro stability. The nanoparticles were pH sensitive and could accelerate drug release at low pH conditions. In vitro experiments showed that THCD-NPs were significantly cytotoxic to HepG2 cells and could be effectively taken up by these cells. Detailed investigations also demonstrated its pro-apoptotic activity. In vivo NIR fluorescence imaging showed that the nanoparticles could accumulate efficiently at the tumor site. Meanwhile, in vivo experiments showed that THCD-NPs significantly inhibited tumor growth and reduced the toxic side effects of free drugs in a mouse solid tumor model. In short, the nanoparticles we prepared provide a new idea for the treatment of liver cancer.

The improvement of biocompatibility by incorporating porphyrins into carbon dots with photodynamic effects and pH sensitivities

Photodynamic therapy (PDT) is a promising new treatment for cancer; however, the hydrophobic interactions and poor solubility in water of photosensitizers limit the use in clinic. Nanoparticles especially carbon dots have attracted the attention of the world^'s scientists because of their unique properties such as good solubility and biocompatibility. In this paper, we integrated carbon dots with different porphyrins to improve the properties of porphyrins and evaluated their efficacy as PDT drugs. The spectroscopic characteristics of porphyrins nano-conjugates were studied. Singlet oxygen generation rate and the light- and dark-induced toxicity of the conjugates were studied. Our results showed that the covalent interaction between CDs and porphyrins has improved the biocompatibility. The synthesized conjugates also inherit the pH sensitivity of the carbon dots, while the conjugation also decreases the hemolysis ratio making them a promising candidate for PDT. The incorporation of carbon dots into porphyrins improved their biocompatibility by reducing toxicity.

Hyaluronic Acid-Conjugated Carbon Nanomaterials for Enhanced Tumour Targeting Ability

Hyaluronic acid (HA) has been implemented for chemo and photothermal therapy to target tumour cells overexpressing the CD44+ receptor. HA-targeting hybrid systems allows carbon nanomaterial (CNM) carriers to efficiently deliver anticancer drugs, such as doxorubicin and gemcitabine, to the tumour sites. Carbon nanotubes (CNTs), graphene, graphene oxide (GO), and graphene quantum dots (GQDs) are grouped for a detailed review of the novel nanocomposites for cancer therapy. Some CNMs proved to be more successful than others in terms of stability and effectiveness at removing relative tumour volume. While the literature has been focused primarily on the CNTs and GO, other CNMs such as carbon nano-onions (CNOs) proved quite promising for targeted drug delivery using HA. Near-infrared laser photoablation is also reviewed as a primary method of cancer therapy-it can be used alone or in conjunction with chemotherapy to achieve promising chemo-photothermal therapy protocols. This review aims to give a background into HA and why it is a successful cancer-targeting component of current CNM-based drug delivery systems.

Computational study of therapeutic potential of phosphorene as a nano-carrier for drug delivery of nebivolol for the prohibition of cardiovascular diseases: a DFT study

Density functional theory (DFT) calculations were utilized to assess the drug delivery efficiency of phosphorene carrier for nebivolol drug to treat cardiovascular diseases. The optimized structures, excited state, and electronic properties of nebivolol, phosphorene, and nebivolol-phosphorene (nebivolol-PH) complex were considered to determine the drug delivery ability of phosphorene at the target site. The increased dipole moment (6.08 D) results in the higher solubility of the complex in polar solvents (water). Weak interactive forces between nebivolol and phosphorene were demonstrated by the non-covalent interaction (NCI) plot that facilitated the offloading of nebivolol at the targeted area. The analysis of frontier molecular orbitals (FMOs) revealed that during excitation, the charge was transferred from nebivolol as a higher occupied molecular orbital (HOMO) to phosphorene as a lower unoccupied molecular orbital (LUMO). Thus, the charge-transfer process was further studied by charge decomposition analysis (CDA). The calculated results at the excited state for the nebivolol-PH complex exhibited that the maximum wavelength (λmax) was red-shifted by 6 nm in the gas phase. The electron-hole theory and photoinduced electron transfer (PET) processes were carried out for the exploration of different excited states of the complex. Additionally, phosphorene with + 1 and - 1 charge states indicated the minor structural changes and provide the stable nebivolol-PH complex. This theoretical study also investigated that phosphorene can be exploited as an effective carrier for the delivery of a therapeutic agent as nebivolol to treat cardiovascular diseases. This work will also encourage the researchers to investigate the other 2D nanoparticles as a nano-drug delivery system (NDDS).

Hyaluronic acid-based nanogels derived from multicomponent self-assembly for imaging-guided chemo-photodynamic cancer therapy

Multifunctional theranostic nanoplatforms integrated of imaging function, multi-modality therapy, stimuli-responsiveness, and targeted delivery are of highly desirable attributes in achieving precise medicine. However, preparation of multifunctional nanoplatforms often involves laborious, multiple steps and inevitably utilizes low-biocompatible or non-functional components. Herein we report a facile, one-step self-assembly strategy to fabricate hyaluronic acid (HA)-based multifunctional tumor theranostic nanoplatform by employing magnetic resonance imaging (MRI) agent Mn2+ as a reversible crosslink agent for histidine-grafted HA, along with simultaneously loading chemotherapeutic agent doxorubicin hydrochloride (DOX) and photodynamic therapy agent chlorin e6, to realize MRI-guided targeted chemo-photodynamic cancer therapy. The targeted delivery and stimuli-responsive payload release were demonstrated in vitro and in vivo. Furthermore, the combined chemo-photodynamic therapy of the nanoassembly dramatically improved the cancer therapeutic outcome, in comparison with that of free DOX and nanoplatform solely loaded DOX in a melanoma bearing mice. Our one step assemble strategy is of great potential in clinic transformation.

Hyaluronic acid-modified manganese dioxide-enveloped hollow copper sulfide nanoparticles as a multifunctional system for the co-delivery of chemotherapeutic drugs and photosensitizers for efficient synergistic antitumor treatments

This paper presents the design of a new type of intelligent and versatile all-in-one therapeutic nanoplatform for the co-delivery of chemotherapeutic drugs and photosensitizers to facilitate multimodal antitumor treatment; the system is based on hyaluronic acid (HA)-modified manganese dioxide (MnO₂)-enveloped hollow porous copper sulfide (CuS) nanoparticles (CuS@MnO₂/HA NPs). In this system, a CuS inner shell allows for the co-loading of doxorubicin (DOX) and indocyanine green (ICG) and induces photothermal effects, and a biodegradable MnO₂ external shell affords on-demand tumor microenvironment (TME)-triggered release and catalase- andFenton-like activities. Moreover, the HA modification endows the system with a CD44 receptor-mediated tumor-targeting property. The formulated DOX and ICG co-loaded CuS@MnO₂/HA (DOX/ICG-CuS@MnO₂/HA) NPs were found to exhibit excellent photothermal performance both in vitro and in vivo. In addition, DOX/ICG-CuS@MnO₂/HA NPs were found to display both TME and near-infrared (NIR)-responsive controlled release properties. The NPs also have a superior reactive oxygen species (ROS) generation capacity due to the combination of enhanced ICG-induced singlet oxygen and CuS@MnO₂-mediated hydroxyl radicals. The cellular uptake, fluorescence imaging property, cytotoxicity, and thermal imaging of these NPs were also evaluated. In tumor-bearing mice, the DOX/ICG-CuS@MnO₂/HA NPs displayeda superior antitumor efficacy (2.57-fold) as compared with free DOX. Therefore, the developed DOX/ICG-CuS@MnO₂/HA NPs have a great potential for use as an all-in-one nanotherapeutic agent for the efficient and precise induction of chemo/photothermal/photodynamic/chemodynamic therapy with superior antitumor efficacy and fewer side effects.

Functionalization of Graphene Oxide with Porphyrins: Synthetic Routes and Biological Applications

Among the available carbon nanomaterials, graphene oxide (GO) has been widely studied because of the possibility of anchoring different chemical species for a large number of applications, including those requiring water-compatible systems. This Review summarizes the state-of-the-art of synthetic routes used to functionalize GO, such as those involving multiple covalent and non-covalent bonds to organic molecules, functionalization with nanoparticles and doping. As a recent development in this field, special focus is given to the formation of nanocomposites comprising GO and porphyrins, and their characterization through spectroscopic techniques (such as UV-Vis, fluorescence, Raman spectroscopy), among others. The potential of such hybrid systems in targeted biological applications is also discussed, namely for cancer therapies relying on photodynamic and photothermal therapies and for the inhibition of telomerase enzyme. Lastly, some promising alternative materials to GO are presented to overcome current challenges of GO-based research and to inspire future research directions in this field.

Organic/inorganic nanohybrids rejuvenate photodynamic cancer therapy

The development of nanotechnology has changed the 100-year-old paradigm of photodynamic therapy (PDT), in which organic/inorganic hybrid nanomaterials have made great contributions. In this review, we first describe the mechanisms of PDT and discuss the limitations of conventional PDT. On this basis, we summarize recent progress in organic/inorganic nanohybrids-based photodynamic agents, highlighting how these nanohybrids can be programmed to overcome challenges in photodynamic cancer therapy.

2D LDH-MoS2 clay nanosheets: synthesis, catalase-mimic capacity, and imaging-guided tumor photo-therapy

Owing to the hypoxia status of the tumor, the reactive oxygen species (ROS) production during photodynamic therapy (PDT) of the tumor is less efficient. Herein, a facile method which involves the synthesis of Mg-Mn-Al layered double hydroxides (LDH) clay with MoS2 doping in the surface and anionic layer space of LDH was presented, to integrate the photo-thermal effect of MoS2 and imaging and catalytic functions of Mg-Mn-Al LDH. The designed LDH-MoS2 (LMM) clay composite was further surface-coated with bovine serum albumin (BSA) to maintain the colloidal stability of LMM in physiological environment. A photosensitizer, chlorin e6 (Ce6), was absorbed at the surface and anionic layer space of LMM@BSA. In the LMM formulation, the magnetic resonance imaging of Mg-Mn-Al LDH was enhanced thanks to the reduced and acid microenvironment of the tumor. Notably, the ROS production and PDT efficiency of Ce6 were significantly improved, because LMM@BSA could catalyze the decomposing of the overexpressed H2O2 in tumors to produce oxygen. The biocompatible LMM@BSA that played the synergism with tumor microenvironment is a promising candidate for the effective treatment of cancer.

Construction of a Mesoporous Polydopamine@GO/Cellulose Nanofibril Composite Hydrogel with an Encapsulation Structure for Controllable Drug Release and Toxicity Shielding

The development of intelligent and multifunctional hydrogels having photothermal properties, good mechanical properties, sustained drug release abilities with low burst release, antibacterial properties, and biocompatibility is highly desirable in the biomaterial field. Herein, mesoporous polydopamine (MPDA) nanoparticles wrapped with graphene oxide (GO) were physically cross-linked in cellulose nanofibril (CNF) hydrogel to obtain a novel MPDA@GO/CNF composite hydrogel for controllable drug release. MPDA nanoparticles exhibited a high drug loading ratio (up to 35 wt %) for tetracycline hydrochloride (TH). GO was used to encapsulate MPDA nanoparticles for extending the drug release time and reinforcing the physical strength of the obtained hydrogel. The mechanical strength of the as-fabricated MPDA@GO/CNF composite hydrogel was five times greater compared to that of the pure CNF hydrogel. Drug release experiments demonstrated that burst release behavior was significantly reduced by adding MPDA@GO. The drug release time of the MPDA@GO/CNF composite hydrogel was 3 times and 7.2 times longer than that of the polydopamine/CNF hydrogel and pure CNF hydrogel, respectively. The sustained and controlled drug release behaviors of the composite hydrogel were highly dependent on the proportion of MPDA and GO. Moreover, the rate of drug release could be accelerated by near-infrared (NIR) light irradiation and pH value change. The drug release kinetics of the as-prepared composite hydrogel was well described by the Korsmeyer-Peppas model, and the drug release mechanism of TH from the composite hydrogel was anomalous transport. Importantly, this carefully designed MPDA@GO/CNF composite hydrogel showed good biocompatibility through an in vitro cytotoxicity test. In particular, the toxicity of GO was well shielded by the CNF hydrogel. Therefore, this novel MPDA@GO/CNF composite hydrogel with an encapsulation structure for controllable drug release and toxicity shielding of GO could be used as a very promising controlled drug delivery carrier, which may have potential applications for chemical and physical therapies.

Ligand-Targeted Delivery of Photosensitizers for Cancer Treatment

Photodynamic therapy (PDT) is a promising cancer treatment which involves a photosensitizer (PS), light at a specific wavelength for PS activation and oxygen, which combine to elicit cell death. While the illumination required to activate a PS imparts a certain amount of selectivity to PDT treatments, poor tumor accumulation and cell internalization are still inherent properties of most intravenously administered PSs. As a result, common consequences of PDT include skin photosensitivity. To overcome the mentioned issues, PSs may be tailored to specifically target overexpressed biomarkers of tumors. This active targeting can be achieved by direct conjugation of the PS to a ligand with enhanced affinity for a target overexpressed on cancer cells and/or other cells of the tumor microenvironment. Alternatively, PSs may be incorporated into ligand-targeted nanocarriers, which may also encompass multi-functionalities, including diagnosis and therapy. In this review, we highlight the major advances in active targeting of PSs, either by means of ligand-derived bioconjugates or by exploiting ligand-targeting nanocarriers.

pH-responsive hyaluronic acid-based nanoparticles for targeted curcumin delivery and enhanced cancer therapy

Curcumin (CUR) display promising antitumor effects, however, the poor water solubility severely limited its clinical application. To overcome this problem, polymeric nanocarriers have been adopted for targeted CUR delivery and enhanced cancer therapy. In this paper, utilizing an acid-labile hydrazone linkage, hydrophobic CUR was conjugated with hydrophilic hyaluronic acid (HA) to form amphiphilic HA-ADH-CUR conjugates, which could subsequently self-assemble to form nanoparticles (HA@CUR NPs) in aqueous. The in vitro drug release experiments showed that HA@CUR NPs exhibited a pH-responsive CUR release behavior, and the release rate of CUR was 73.5 % in pH 5.0. Further, in vitro cell experiments showed HA@CUR NPs could be efficiently internalized by 4T1 and MCF-7 cancer cells through CD44 receptor mediated endocytosis and successfully release CUR in acidic lysosome environment for chemotherapy. In vivo antitumor experiments showed that, compared to free CUR, HA@CUR NPs could efficiently cumulate in tumor site via EPR effect and CD44 mediated endocytosis, achieve superior therapeutic effect for tumor growth suppression. Therefore, HA@CUR NPs were a highly promising nanocarrier for hydrophobic CUR to realize enhanced cancer therapy with good biosafety.

Disrupted intracellular redox balance with enhanced ROS generation and sensitive drug release for cancer therapy

In this paper, a nanocomposite was constructed to achieve improved photodynamic therapy (PDT) via disrupting the redox balance in cancer cells. Firstly, Sb₂Se₃ nanorods were synthesized as a new photosensitizer, displaying high photothermal conversion efficiency (45.2%) and reactive oxygen species (ROS) production due to the narrow band gap (1.1 eV) and a good NIR response. Moreover, the mechanism was investigated, demonstrating that dissolved O₂ and photoinduced electrons manipulated ROS generation. Then, mesoporous silica was coated outside to improve the biocompatibility and to supply abundant space for the anticancer drug (doxorubicin, DOX). The sensitive Se-Se linker was grafted outside via a silane coupling reaction to block DOX molecules in the mesopores. As we know, the Se-Se group is sensitive to GSH, which can induce Se-Se linker bond breakage and targeted drug release due to the high expression of GSH in tumor cells. What is more, the consumption of intracellular GSH can also disrupt the redox balance in cancer cells, which would promote the PDT efficiency. The high-Z element of Sb possesses a high X-ray attenuation coefficient, giving the composite high contrast in CT imaging. This is associated with thermal imaging and multi-therapy (PDT/PTT/chemotherapy) to reveal the potential application to cancer treatment.

Functionalized Graphene Oxide for Chemotherapeutic Drug Delivery and Cancer Treatment: A Promising Material in Nanomedicine

The usage of nanomaterials for cancer treatment has been a popular research focus over the past decade. Nanomaterials, including polymeric nanomaterials, metal nanoparticles, semiconductor quantum dots, and carbon-based nanomaterials such as graphene oxide (GO), have been used for cancer cell imaging, chemotherapeutic drug targeting, chemotherapy, photothermal therapy, and photodynamic therapy. In this review, we discuss the concept of targeted nanoparticles in cancer therapy and summarize the in vivo biocompatibility of graphene-based nanomaterials. Specifically, we discuss in detail the chemistry and properties of GO and provide a comprehensive review of functionalized GO and GO-metal nanoparticle composites in nanomedicine involving anticancer drug delivery and cancer treatment.

Effective Photodynamic Therapy for Colon Cancer Cells Using Chlorin e6 Coated Hyaluronic Acid-Based Carbon Nanotubes

Colon cancer is the third major cancer contributor to mortality worldwide. Nanosized particles have attracted attention due to their possible contribution towards cancer treatment and diagnosis. Photodynamic therapy (PDT) is a cancer therapeutic modality that involves a light source, a photosensitizer and reactive oxygen species. Carbon nanotubes are fascinating nanocarriers for drug delivery, cancer diagnosis and numerous potential applications due to their unique physicochemical properties. In this study, single walled carbon nanotubes (SWCNTs) were coupled with hyaluronic acid (HA) and chlorin e6 (Ce6) coated on the walls of SWCNTs. The newly synthesized nanobiocomposite was characterized using ultraviolet-visible spectroscopy, Fourier transform electron microscopy (FTIR), X-ray diffraction analysis (XRD), particle size analysis and zeta potential. The loading efficiency of the SWCNTs-HA for Ce6 was calculated. The toxicity of the nanobiocomposite was tested on colon cancer cells using PDT at a fluence of 5 J/cm² and 10 J/cm². After 24 h, cellular changes were observed via microscopy, LDH cytotoxicity assay and cell death induction using annexin propidium iodide. The results showed that the newly synthesized nanobiocomposite enhanced the ability of PDT to be a photosensitizer carrier and induced cell death in colon cancer cells.

When polymers meet carbon nanostructures: expanding horizons in cancer therapy

The development of hybrid materials, which combine inorganic with organic materials, is receiving increasing attention by researchers. As a consequence of carbon nanostructures high chemical versatility, they exhibit enormous potential for new highly engineered multifunctional nanotherapeutic agents for cancer therapy. Whereas many groups are working on drug delivery systems for chemotherapy, the use of carbon nanohybrids for radiotherapy is rarely applied. Thus, nanotechnology offers a wide range of solutions to overcome the current obstacles of conventional chemo- and/or radiotherapies. Within this review, the structure and properties of carbon nanostructures (carbon nanotubes, nanographene oxide) functionalized preferentially with different types of polymers (synthetic, natural) are discussed. In short, synthesis approaches, toxicity investigations and anticancer efficacy of different carbon nanohybrids are described.

Nanoconjugates of graphene oxide derivatives and meso-tetraphenylporphyrin: a new avenue for anticancer photodynamic therapies – Cell-on-a-Chip analysis

Cell-on-a-Chip analysis of nanoconjugates of graphene oxide derivatives and mesotetraphenylporphyrin as a new selective and effective avenue for anticancer photodynamic therapies.

Hyaluronic acid conjugated polydopamine functionalized mesoporous silica nanoparticles for synergistic targeted chemo-photothermal therapy

The integration of chemotherapy and photothermal therapy into one nanoplatform has attracted much attention for synergistic tumor treatment, but the practical clinical applications were usually limited by their synergistic effects and low selectivity for disease sites. To overcome these limitations, a tumor-specific and pH/NIR dual-responsive multifunctional nanocarrier coated with mussel inspired polydopamine and further conjugated with targeting molecular hyaluronic acid (HA) was designed and fabricated for synergistic targeted chemo-photothermal therapy. The synthesized versatile nanoplatform displayed strong near-infrared absorption because of the successful formation of polydopamine coating. Furthermore, the nanosystem revealed high storage capacity for drugs and pH/NIR dual-responsive release performance, which could effectively enhance the chemo-photothermal therapy effect. With this smart design, in vitro experimental results confirmed that the drug loaded multifunctional nanoparticles could be efficiently taken up by cancer cells, and exhibited remarkable tumor cell killing efficiency and excellent photothermal properties. Meanwhile, significant tumor regression in the tumor-bearing mice model was also observed due to the combination of chemotherapy and photothermal therapy. Thus, this work indicated that the simple multifunctional nanoplatform can be applied as an efficient therapeutic agent for site-specific synergistic chemo-photothermal therapy.

A Composite of Hyaluronic Acid-Modified Graphene Oxide and Iron Oxide Nanoparticles for Targeted Drug Delivery and Magnetothermal Therapy

Graphene oxide (GO) nanoparticles have been developed for a variety of biomedical applications as a number of different therapeutic modalities may be added onto them. Here, we report the development and testing of such a multifunctional GO nanoparticle platform that contains a grafted cell-targeting functionality, active pharmaceutical ingredients, and particulates that enable the use of magnetothermal therapy. Specifically, we demonstrate the ability to covalently attach hyaluronic acid (HA) onto GO, and the resultant nanoparticulates (GO-HA) exhibited low inherent toxicity toward two different breast cancer cell lines, BT-474 and MDA-MB-231. Doxorubicin (Dox) and paclitaxel (Ptx) were successfully loaded onto GO-HA with high and moderate efficiencies, respectively. A GO-HA-Dox/Ptx system was significantly better than the GO-Dox/Ptx system at specifically killing CD44-expressing MDA-MB-231 cells but not BT-474 cells that do not express CD44. Further, modified iron oxide nanoparticles were loaded onto the GO-HA-Dox system, enabling the use of magnetic hyperthermia. Hyperthermia in combination with Dox treatment through the GO-HA system showed significantly better performance in reducing viable tumor cell numbers when compared to the individual systems. In summary, we showcase a multifunctional GO nanoparticle system that demonstrates improved efficacy in killing tumor cells.

Reactive oxygen species and near-infrared light dual-responsive indocyanine green-loaded nanohybrids for overcoming tumour multidrug resistance

The nucleus is in charge of the metabolism and heredity of the cell, and genetic mutations are closely related with tumour multidrug resistance (MDR). Indocyanine green (ICG), the FDA-approved photosensitizer, is widely used for tumour photodynamic therapy (PDT) and photothermal therapy (PTT). Few studies have clarified the cellular distribution of ICG in MDR tumour cells. In the study, ICG distribution was detected in the whole tumour cells of MCF-7 and MCF-7/ADR, especially in the nucleus, which led us to question whether increasing cellular accumulation and nuclear distribution of ICG could be a potential method to overcome MDR. Therefore, a reactive oxygen species (ROS) and near-infrared (NIR) light dual-responsive nanohybrid was constructed with diselenide cross-linked polyamidoamine-Poloxamer 188 and graphene oxide with ICG as payloads (ICG/GPP). The nanohybrid enhanced the stability of ICG and showed an ROS-sensitive release behaviour. More ICG was delivered by ICG/GPP to the MCF-7/ADR cells. After escaping from the lysosome, nuclear accumulation of ICG was increased. Under NIR laser irradiation, ICG/GPP showed increased cytotoxicity for the combined PTT and PDT in MCF-7/ADR cells. Moreover, the expression of P-glycoprotein (P-gp) was suppressed to overcome tumour MDR. The ROS- and NIR- responsive GPP shows potential for the nuclear delivery of drugs to combat tumour MDR.

Multifunctional Nanosystem Based on Graphene Oxide for Synergistic Multistage Tumor-Targeting and Combined Chemo-Photothermal Therapy

Locating nanomedicines at the active sites plays a pivotal role in the nanoparticle-based cancer therapy field. Herein, a multifunctional nanotherapeutic is designed by using graphene oxide (GO) nanosheets with rich carboxyl groups as the supporter for hyaluronic acid (HA)-methotrexate (MTX) prodrug modification via an adipicdihydrazide cross-linker, achieving synergistic multistage tumor-targeting and combined chemo-photothermal therapy. As a tumor-targeting biomaterial, HA can increase affinity of the nanocarrier toward CD44 receptor for enhanced cellular uptake. MTX, a chemotherapeutic agent, can also serve as a tumor-targeting enhancer toward folate receptor based on its similar structure with folic acid. The prepared nanosystems possess a sheet shape with a dynamic size of approximately 200 nm and pH-responsive drug release. Unexpectedly, the physiological stability of HA-MTX prodrug-decorated GO nanosystems in PBS, serum, and even plasma is more excellent than that of HA-decorated GO nanosystems, while both of them exhibit an enhanced photothermal effect than GO nanosheets. More importantly, because of good blood compatibility as well as reduced undesired interactions with blood components, HA-MTX prodrug-decorated GO nanosystems exhibited remarkably superior accumulation at the tumor sites by passive and active targeting mechanisms, achieving highly effective synergistic chemo-photothermal therapeutic effect upon near-infrared laser irradiation, efficient ablation of tumors, and negligible systemic toxicity. Hence, the HA-MTX prodrug-decorated hybrid nanosystems have a promising potential for synergistic multistage tumor-targeting therapy.

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.

Polymeric Engineering of Nanoparticles for Highly Efficient Multifunctional Drug Delivery Systems

Most targeting strategies of anticancer drug delivery systems (DDSs) rely on the surface functionalization of nanocarriers with specific ligands, which trigger the internalization in cancer cells via receptor-mediated endocytosis. The endocytosis implies the entrapment of DDSs in acidic vesicles (endosomes and lysosomes) and their eventual ejection by exocytosis. This process, intrinsic to eukaryotic cells, is one of the main drawbacks of DDSs because it reduces the drug bioavailability in the intracellular environment. The escape of DDSs from the acidic vesicles is, therefore, crucial to enhance the therapeutic performance at low drug dose. To this end, we developed a multifunctionalized DDS that combines high specificity towards cancer cells with endosomal escape capabilities. Doxorubicin-loaded mesoporous silica nanoparticles were functionalized with polyethylenimine, a polymer commonly used to induce endosomal rupture, and hyaluronic acid, which binds to CD44 receptors, overexpressed in cancer cells. We show irrefutable proof that the developed DDS can escape the endosomal pathway upon polymeric functionalization. Interestingly, the combination of the two polymers resulted in higher endosomal escape efficiency than the polyethylenimine coating alone. Hyaluronic acid additionally provides the system with cancer targeting capability and enzymatically controlled drug release. Thanks to this multifunctionality, the engineered DDS had cytotoxicity comparable to the pure drug whilst displaying high specificity towards cancer cells. The polymeric engineering here developed enhances the performance of DDS at low drug dose, holding great potential for anticancer therapeutic applications.

Recent Advances in Carbon Nanomaterials for Cancer Phototherapy

Carbon nanomaterials have received great attention from the scientific community over the past few decades because of their unique physical and chemical properties. In this minireview, we will summarize the recent progress of the use of various carbon nanomaterials in the field of cancer phototherapy. The structural characteristics of each category and the surface functionalization strategies of these nanomaterials will be briefly introduced before focusing on their therapeutic applications. Recent advances on their use in photothermal therapy, photodynamic therapy, and combined phototherapies are presented. Moreover, a few challenges and perspectives on the development of carbon nanomaterials for future theranostics are also discussed.

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.

Poly(glycidyl methacrylate)-coated magnetic graphene oxide as a highly efficient nanocarrier: preparation, characterization, and targeted DOX delivery

Herein, we report the preparation of novel magnetic graphene oxide grafted with brush polymer via SI-RAFT polymerization and its application as a nanocarrier for magnetic and pH-triggered delivery of DOX anticancer drug.