Graphene-based nanomaterials and their potentials in advanced drug delivery and cancer therapy

Effects of the Surface Charge of Graphene Oxide Derivatives on Ocular Compatibility

The incorporation of functional groups endows graphene oxide (GO) with different surface charges, which plays important roles in biological interactions with cells. However, the effect of surface charge of GO derivatives on ocular biocompatibility has not been fully elucidated. Previously, we found that positively, negatively and neutrally charged PEGylated GO (PEG-GO) nanosheets exerted similar effect on the viability of ocular cells. In this work, we performed in vitro and in vivo studies to comprehensively study the effect of surface charge of PEG-GO on ocular compatibility. The in vitro results showed that the cellular uptake efficacy of negatively charged PEG-GO nanosheets was significantly decreased compared with positively charged and neutrally charged analogs. However, three kinds of PEG-GO nanosheets produced similar amounts of intracellular reactive oxygen species and showed similar influence on mitochondrial membrane potential. By analysis of global gene expression profiles, we found that the correlation coefficients between three kinds of PEG-GO-treated cells were more than 0.98. Furthermore, in vivo results showed that all these PEG-GO nanosheets had no significant toxicity to ocular structure and function. Taken together, our work suggested that surface charge of PEG-GO exerted negligible effect on its ocular compatibility, except for the cellular uptake. Our work is conducive to understanding the relationship between surface charge and biocompatibility of GO derivatives.

Biomedical applications of chitosan-graphene oxide nanocomposites

Chitosan (CS) and graphene oxide (GO) nanocomposites have received wide attention in biomedical fields due to the synergistic effect between CS which has excellent biological characteristics and GO which owns great physicochemical, mechanical, and optical properties. Nanocomposites based on CS and GO can be fabricated into a variety of forms, such as nanoparticles, hydrogels, scaffolds, films, and nanofibers. Thanks to the ease of functionalization, the performance of these nanocomposites in different forms can be further improved by introducing other functional polymers, nanoparticles, or growth factors. With this background, the current review summarizes the latest developments of CS-GO nanocomposites in different forms and compositions in biomedical applications including drug and biomacromolecules delivery, wound healing, bone tissue engineering, and biosensors. Future improving directions and challenges for clinical practice are proposed as well.

Spontaneous desorption of protein from self-assembled monolayer (SAM)-coated gold nanoparticles induced by high temperature

The nonspecific binding of proteins with nanomaterials (NMs) is a dynamic reversible process including both protein adsorption and desorption parts, which is crucial for controlled release of protein drug loaded by nanocarriers. The nonspecific binding of proteins is susceptible to high temperature, whereas its underlying mechanism still remains elusive. Here, the binding behavior of human serum albumin (HSA) with an amino-terminated self-assembled monolayer (SAM)-coated gold (111) surface was investigated by using molecular dynamics (MD) simulations. HSA binds to the SAM surface through salt bridges at 300 K. As the temperature increases to 350 K, HSA maintains its native structure, while the salt bridges largely diminish owing to the considerable lateral diffusion of HSA on the SAM. Moreover, the interfacial water located between HSA and the SAM gets increased and prevents the reformation of the salt bridges of HSA with the SAM, which reduces the binding affinity of HSA. And HSA eventually desorbs from the SAM. The depiction of thermally induced spontaneous protein desorption enriches our understanding of reversible binding behavior of protein with NMs, and may provide new insights into the controlled release of protein drugs delivered by using nanocarriers under the regulation of high temperature.

Electroconductive and photoactive poly(phenylenediamine)s with antioxidant and antimicrobial activities for potential photothermal therapy

In recent years, polyaniline derivatives such as poly(phenylenediamine)s have attracted the attention of researchers due to their better solubility, good optical and electrical properties. In the current work, poly(ortho- phenylenediamine)...

Synthesis, Applications, and Prospects of Graphene Quantum Dots: A Comprehensive Review

Graphene quantum dot (GQD) is one of the youngest superstars of the carbon family. Since its emergence in 2008, GQD has attracted a great deal of attention due to its unique optoelectrical properties. Non-zero bandgap, the ability to accommodate functional groups and dopants, excellent dispersibility, highly tunable properties, and biocompatibility are among the most important characteristics of GQDs. To date, GQDs have displayed significant momentum in numerous fields such as energy devices, catalysis, sensing, photodynamic and photothermal therapy, drug delivery, and bioimaging. As this field is rapidly evolving, there is a strong need to identify the emerging challenges of GQDs in recent advances, mainly because some novel applications and numerous innovations on the ease of synthesis of GQDs are not systematically reviewed in earlier studies. This feature article provides a comparative and balanced discussion of recent advances in synthesis, properties, and applications of GQDs. Besides, current challenges and future prospects of these emerging carbon-based nanomaterials are also highlighted. The outlook provided in this review points out that the future of GQD research is boundless, particularly if upcoming studies focus on the ease of purification and eco-friendly synthesis along with improving the photoluminescence quantum yield and production yield of GQDs.

Multifunctional Nanosystems with Enhanced Cellular Uptake for Tumor Therapy

Rapid development of nanotechnology provides promising strategies in biomedicine, especially in tumor therapy. In particular, the cellular uptake of nanosystems is not only a basic premise to realize various biomedical applications, but also a fatal factor for determining the final therapeutic effect. Thus, a systematic and comprehensive summary is necessary to overview the recent research progress on the improvement of nanosystem cellular uptake for cancer treatment. According to the process of nanosystems entering the body, they can be classified into three categories. The first segment is to enhance the accumulation and permeation of nanosystems to tumor cells through extracellular microenvironment stimulation. The second segment is to improve cellular internalization from extracellular to intracellular via active targeting. The third segment is to enhance the intracellular retention of therapeutics by subcellular localization. The major factors in the delivery can be utilized to develop multifunctional nanosystems for strengthening the tumor therapy. Ultimately, the key challenges and prospective in the emerging research frontier are thoroughly outlined. This review is expected to provide inspiring ideas, promising strategies and potential pathways for developing advanced anticancer nanosystems in clinical practice.

DNA aptamer-based dual-responsive nanoplatform for targeted MRI and combination therapy for cancer

Accurate drug delivery is a common topic, and it has always been an aim that scientists strive to achieve. To address this need, multifunctional and stimulus-sensitive nanoplatforms have attracted significant attention. Here we fabricated a glutathione (GSH) and adenosine-5′-triphosphate (ATP) dual-sensitive nanoplatform for controlled drug release and activatable MRI of tumors based on DNA aptamer and manganese dioxide (MnO₂) nanosheets. Cleverly utilizing the DNA tunability, AS1411 aptamer which binds nucleolin, a protein specifically expressed on tumor-associated endothelial cells, was designed with ATP aptamer and its cDNA to load the anticancer drug, doxorubicin (Dox). The formed DNA-Dox complex was delivered to the tumor region with the help of MnO₂ nanosheets and AS1411 aptamer. Then, the on-demand drug release in tumor cells was realized with the co-effect of the ATP aptamer and GSH reduction. It was found that without the structure of the MnO₂ nanosheets being broken by GSH, Dox almost could not be released even in the presence of ATP. Similarly, without ATP, Dox was still maintained in the duplex even with GSH. Further combining the MRI ability and chemodynamic therapy of the produced Mn²⁺, an improved effect of the inhibition of tumor growth and imaging was achieved. Our designed DNA aptamer-based dual-responsive nanoplatform can realize the targeted drug delivery and MRI of breast tumor cells both in vitro and in vivo.

A glutathione (GSH) and adenosine-5′-triphosphate (ATP) dual-sensitive nanoplatform was designed for controlled drug release and activatable MRI of tumors based on DNA aptamer and manganese dioxide (MnO₂) nanosheets.

Synthesis of manganese-oxide and palladium nanoparticles co-decorated polypyrrole/graphene oxide (MnO2@Pd@PPy/GO) nanocomposites for anti-cancer treatment

Design and fabrication of novel multifunctional nanomaterials as novel “theranostic nanoagents”with high efficiency and low side effects is important for cancer treatment. Herein, we synthesized manganese-oxide and palladium nanoparticle-co-decorated polypyrrole/graphene oxide (MnO₂@Pd@PPy/GO) nanocomposites, which could be used as a novel “theranostic nanoagent” for cancer treatment. Various spectroscopic and microscopic characterizations of the synthesized MnO₂@Pd@PPy/GO nanocomposites suggest that the nanocomposites are assembled sequentially by graphene oxide, polypyrrole, palladium nanoparticles and manganese-oxide nanoplates. Further research revealed that the nanocomposites had excellent photothermal conversion performance (reached near 50 °C after 10 min of irradiation), pH responsive enzymatic-like catalytic activity and enhanced magnetic resonance imaging (MRI) performance (r₁ = 7.74 mM⁻¹ s⁻¹ at pH 5.0 and glutathione (GSH)). Cell experiments also testified that combined cancer treatment (the viability of cancer cells is 30%) with photothermal therapy (PTT, the viability of cancer cells is 91% only with irradiation) and chemodynamic therapy (CDT, the viability of cancer cells is 74.7% only with nanocomposites) guided by MRI was achieved when the as-prepared nanocomposites were employed as theranostic nanoagents. This work could provide some new ideas for the controllable synthesis and application of multicomponent nanomaterials.

Manganese-oxide and palladium nanoparticle-co-decorated polypyrrole/graphene oxide (MnO₂@Pd@PPy/GO) nanoenzyme composites were synthesized, and could be as a novel “theranostic nanoagent” for cancer treatment due to excellent performance.

Structural analysis of an iron-assisted carbon monolayer for delivery of 2-thiouracil

An idea of employing an iron-assisted carbon (FeC) monolayer for delivery of 2-thiouracil (2TU) was examined in this work by analyzing structural features for singular and bimolecular models. Density functional theory (DFT) calculations were performed for optimizing the structures and evaluating molecular and atomic descriptors for analyzing the models systems. Two bimolecular models were obtained assigning by S-FeC and O-FeC models, in which each of S and O atom of 2TU was relaxed towards the Fe region of FeC surface in the mentioned models, respectively. The results indicated that both models were achievable with slightly more favorability for formation of S-FeC model. The obtained molecular orbital properties revealed the dominant role of FeC monolayer for managing future interactions of attached 2TU, which is indeed a major role for employing nanomaterials for targeted drug delivery purposes. In addition to energies and molecular orbital features, atomic quadrupole coupling constants indicated the benefit of employing FeC monolayer for drug delivery of 2TU.

Nanoparticles for Cancer Therapy: Current Progress and Challenges

Cancer is one of the leading causes of death and morbidity with a complex pathophysiology. Traditional cancer therapies include chemotherapy, radiation therapy, targeted therapy, and immunotherapy. However, limitations such as lack of specificity, cytotoxicity, and multi-drug resistance pose a substantial challenge for favorable cancer treatment. The advent of nanotechnology has revolutionized the arena of cancer diagnosis and treatment. Nanoparticles (1-100 nm) can be used to treat cancer due to their specific advantages such as biocompatibility, reduced toxicity, more excellent stability, enhanced permeability and retention effect, and precise targeting. Nanoparticles are classified into several main categories. The nanoparticle drug delivery system is particular and utilizes tumor and tumor environment characteristics. Nanoparticles not only solve the limitations of conventional cancer treatment but also overcome multidrug resistance. Additionally, as new multidrug resistance mechanisms are unraveled and studied, nanoparticles are being investigated more vigorously. Various therapeutic implications of nanoformulations have created brand new perspectives for cancer treatment. However, most of the research is limited to in vivo and in vitro studies, and the number of approved nanodrugs has not much amplified over the years. This review discusses numerous types of nanoparticles, targeting mechanisms, and approved nanotherapeutics for oncological implications in cancer treatment. Further, we also summarize the current perspective, advantages, and challenges in clinical translation.

Current Trends and Challenges in Pharmacoeconomic Aspects of Nanocarriers as Drug Delivery Systems for Cancer Treatment

Nanotherapy is a part of nanomedicine that involves nanoparticles as carriers to deliver drugs to target locations. This novel targeting approach has been found to resolve various problems, especially those associated with cancer treatment. In nanotherapy, the carrier plays a crucial role in handling many of the existing challenges, including drug protection before early-stage degradations of active substances, allowing them to reach targeted cells and overcome cell resistance mechanisms. The present review comprises the following sections: the first part presents the introduction of pharmacoeconomics as a branch of healthcare economics, the second part covers various beneficial aspects of the use of nanocarriers for in vitro, in vivo, and pre- and clinical studies, as well as discussion on drug resistance problem and present solutions to overcome it. In the third part, progress in drug manufacturing and optimization of the process of nanoparticle synthesis were discussed. Finally, pharmacokinetic and toxicological properties of nanoformulations due to up-to-date studies were summarized. In this review, the most recent developments in the field of nanotechnology's economic impact, particularly beneficial applications in medicine were presented. Primarily focus on cancer treatment, but also discussion on other fields of application, which are strongly associated with cancer epidemiology and treatment, was made. In addition, the current limitations of nanomedicine and its huge potential to improve and develop the health care system were presented.

Nanomaterials Application in Endodontics

In recent years, nanomaterials have become increasingly present in medicine, especially in dentistry. Their characteristics are proving to be very useful in clinical cases. Due to the intense research in the field of biomaterials and nanotechnology, the efficacy and possibilities of dental procedures have immensely expanded over the years. The nano size of materials allows them to exhibit properties not present in their larger-in-scale counterparts. The medical procedures in endodontics are time-consuming and mostly require several visits to be able to achieve the proper result. In this field of dentistry, there are still major issues about the removal of the mostly bacterial infection from the dental root canals. It has been confirmed that nanoparticles are much more efficient than traditional materials and appear to have superior properties when it comes to surface chemistry and bonding. Their unique antibacterial properties are also promising features in every medical procedure, especially in endodontics. High versatility of use of nanomaterials makes them a powerful tool in dental clinics, in a plethora of endodontic procedures, including pulp regeneration, drug delivery, root repair, disinfection, obturation and canal filling. This study focuses on summing up the current knowledge about the utility of nanomaterials in endodontics, their characteristics, advantages, disadvantages, and provides a number of reasons why research in this field should be continued.

Combating liver cancer through GO-targeted biomaterials

Hydroxycamptothecin (HCPT) is a topoisomerase I inhibitor, and it has been widely used clinically in the treatment of primary liver cancer, gastric cancer, and other tumors. The clinical application of HCPT is limited by its water solubility, and it has certain toxicity to patients with tumor. Therefore, the effective tumor site accumulation of HCPT is necessary. This work studied the inhibitory effect of HCPT on the proliferation and migration of human liver cancer cells (HepG-2) and used carboxymethyl chitosan (CMC) and hyaluronic acid (HA) to modify graphene oxide (GO) as nano-carrier materials, which load HCPT to achieve a drug delivery system for liver tumors with good biocompatibility and high drug loading. HCPT can significantly inhibit proliferation and migration of HepG-2, enhance the release of reactive oxygen species, reduce mitochondrial membrane potential, and induce apoptosis. The GO-CMC-HA/HCPT drug delivery system enabled HepG-2 to uptake more HCPT, thereby inhibiting its proliferation and improving the efficacy of HCPTin vivoandin vitro. This study explored a potential therapy strategy by preparing a GO-based tumor-targeted drug delivery system.

Magnetic and GRPR-targeted reduced graphene oxide/doxorubicin nanocomposite for dual-targeted chemo-photothermal cancer therapy

Herein, we design a rGO-based magnetic nanocomposite by decorating rGO with citrate-coated magnetic nanoparticles (CMNP). The magnetic rGO (mrGO) was modified by phospholipid-polyethylene glycol to prepare PEGylated mrGO, for conjugating with gastrin-releasing peptide receptor (GRPR)-binding peptide (mrGOG). The anticancer drug doxorubicin (DOX) was bound to mrGO (mrGOG) by π-π stacking for drug delivery triggered by the low pH value in the endosome. The mrGOG showed enhanced photothermal effect under NIR irradiation, endorsing its role for dual targeted DOX delivery. With efficient DOX release in the endosomal environment and heat generation from light absorption in the NIR range, mrGOG/DOX could be used for combination chemo-photothermal therapy after intracellular uptake by cancer cells. We characterized the physico-chemical as well as biological properties of the synthesized nanocomposites. The mrGOG is stable in biological buffer solution, showing high biocompatibility and minimum hemolytic properties. Using U87 glioblastoma cells, we confirmed the magnetic drug targeting effect in vitro for selective cancer cell killing. The peptide ligand-mediated targeted delivery increases the efficiency of intracellular uptake of both nanocomposite and DOX up to ~3 times due to the over-expressed GRPR on U87 surface, leading to higher cytotoxicity. The increased cytotoxicity using mrGOG over mrGO was shown from a decreased IC₅₀ value (0.70 to 0.48 μg/mL) and an increased cell apoptosis rate (19.8% to 47.1%). The IC₅₀ and apoptosis rate changed further to 0.19 μg/mL and 76.8% in combination with NIR laser irradiation, with the photothermal effect supported from upregulation of heat shock protein HSP70 expression. Using U87 tumor xenograft model created in nude mice, we demonstrated that magnetic guidance after intravenous delivery of mrGOG/DOX could significantly reduce tumor size and prolong animal survival over free DOX and non-magnetic guided groups. Augmented with NIR laser treatment for 5 min, the anti-cancer efficacy significantly improves with elevated cell apoptosis and reduced cell proliferation. Together with safety profiles from hematological as well as major organ histological analysis of treated animals, the mrGOG nanocomposite is an effective nanomaterial for combination chemo-photothermal cancer therapy.

Functionalized Graphene Platforms for Anticancer Drug Delivery

Two-dimensional nanomaterials are emerging as promising candidates for a wide range of biomedical applications including tissue engineering, biosensing, pathogen incapacitation, wound healing, and gene and drug delivery. Graphene, due to its high surface area, photothermal property, high loading capacity, and efficient cellular uptake, is at the forefront of these materials and plays a key role in this multidisciplinary research field. Poor water dispersibility and low functionality of graphene, however, hamper its hybridization into new nanostructures for future nanomedicine. Functionalization of graphene, either by covalent or non-covalent methods, is the most useful strategy to improve its dispersion in water and functionality as well as processability into new materials and devices. In this review, recent advances in functionalization of graphene derivatives by different (macro)molecules for future biomedical applications are reported and explained. In particular, hydrophilic functionalization of graphene and graphene oxide (GO) to improve their water dispersibility and physicochemical properties is discussed. We have focused on the anticancer drug delivery of polyfunctional graphene sheets.

Extended Release of Metronidazole Drug Using Chitosan/Graphene Oxide Bionanocomposite Beads as the Drug Carrier

This study depicts the facile approach for the synthesis of chitosan/graphene oxide bionanocomposite (Chi/GO) beads via the gelation process. This is the first-ever study in which these Chi/GO beads have been utilized as a drug carrier for the oral drug delivery of metronidazole (MTD) drug, and investigations were made regarding the release pattern of the MTD drug using these Chi/GO beads as a drug carrier for a prolonged period of 84 h. The MTD is loaded on the surface as well as the cavity of the Chi/GO beads to result in MTD-Chi/GO bionanocomposite beads. The MTD drug loading was found to be 683 mg/g. Furthermore, the in vitro release patterns of pure drug and the drug encapsulated with Chi/GO beads are explored in simulated gastric as well as simulated intestinal fluids with phosphate-buffered saline (PBS) of pH 1.2 and 7.4, respectively. As-synthesized bionanocomposite beads have shown excellent stability and capacity for extended release of the MTD drug as compared to the pure drug in terms of bioavailability in both media. The cumulative release data are fitted with the Korsmeyer-Peppas kinetics and first-order reaction kinetics at pH 1.2 and 7.4. The synthesized bionanocomposite beads have good potential to minimize the multiple-dose frequency with the sustained drug release property and can reduce the side effects due to the drug.

Less is more: biological effects of NiSe2/rGO nanocomposites with low dose provide new insight for risk assessment

Nickel selenide nanomaterials (NiSe₂ NMs) with different vacancies demonstrated high catalytic activity as electrocatalyst in oxygen evolution reaction. As the growing needs of the industrial applications in electrocatalyst, the increased occupational exposure and environmental releasing of NMs would be unavoidable. While, much efforts have been made to evaluate the ecological safety of such engineered NMs at unrealistically high concentrations, failed to provide the comprehensively guideline for exposure thresholds. To supplement the current knowledge gap, we testified the cytotoxicity of NiSe₂/rGO nanocomposites with different surface defects under more realistic exposure mode. Compared with the short-term exposure and repetitive exposure, rat lung macrophages exhibited the augmented oxidative stress, dysfunction of mitochondria, damage of DNA and disorder of calcium homeostasis under the long-term NiSe₂/rGO exposure. Noteworthily, no significant differences could be found between the NiSe₂/rGO with different surface defects, indicated that the defect type of NMs were not the accurate predictor for real risk assessment. Collectively, the study provided the real potential toxic effects and exposure thresholds of NMs that might be highly possible industrial produced, and appealed the new insight for risk assessments of engineered NMs under the long-term exposure, which exhibited difference from the traditional evaluation of short-term and repetitive exposure.

Graphene Oxide Nanosheets with Efficient Antibacterial Activity Against Methicillin-Resistant Staphylococcus aureus (MRSA)

The development of drug-resistant bacteria has become a public health problem, among which methicillin-resistant Staphylococcus aureus (MRSA) leads to various life-threatening diseases. Graphene oxide (GO) is a two-dimensional nanomaterial with potential in the anti-MRSA treatment. This study prepared GO nanosheets with fixed lamellar size, investigated its antibacterial activity against MRSA, and analyzed the related antibacterial mechanisms. We found that the fabrication of GO with stable dispersion was workable. Furthermore, such GO had superior antibacterial performance against MRSA at low concentrations with the dose-dependent anti-MRSA effect. The GO-MRSA interaction also provided fundamental support for the antibacterial mechanisms with cleavage and encapsulation effects. In conclusion, GO nanosheets may be a promising antimicrobial agent against MRSA.

Advanced mesoporous silica nanocarriers in cancer theranostics and gene editing applications

Targeted nanomaterials for cancer theranostics have been the subject of an expanding volume of research studies in recent years. Mesoporous silica nanoparticles (MSNs) are particularly attractive for such applications due to possibilities to synthesize nanoparticles (NPs) of different morphologies, pore diameters and pore arrangements, large surface areas and various options for surface functionalization. Functionalization of MSNs with different organic and inorganic molecules, polymers, surface-attachment of other NPs, loading and entrapping cargo molecules with on-desire release capabilities, lead to seemingly endless prospects for designing advanced nanoconstructs exerting multiple functions, such as simultaneous cancer-targeting, imaging and therapy. Describing composition and multifunctional capabilities of these advanced nanoassemblies for targeted therapy (passive, ligand-functionalized MSNs, stimuli-responsive therapy), including one or more modalities for imaging of tumors, is the subject of this review article, along with an overview of developments within a novel and attractive research trend, comprising the use of MSNs for CRISPR/Cas9 systems delivery and gene editing in cancer. Such advanced nanconstructs exhibit high potential for applications in image-guided therapies and the development of personalized cancer treatment.

The protein corona and its effects on nanoparticle-based drug delivery systems

In most cases, once nanoparticles (NPs) enter the blood, their surface is covered by biological molecules, especially proteins, forming a so-called protein corona (PC). As a result, what the cells of the body "see" is not the NPs as formulated by the chemists, but the PC. In this way, the PC can influence the effects of the NPs and even mask the desired effects of the NP components. While this can argue for trying to inhibit protein-nanomaterial interactions, encapsulating NPs in an endogenous PC may increase their clinical usefulness. In this review, we briefly introduce the concept of the PC, its formation and its effects on the behavior of NPs. We also discuss how to reduce the formation of PCs or exploit them to enhance NP functions. Studying the interactions between proteins and NPs will provide insights into their clinical activity in health and disease. STATEMENT OF SIGNIFICANCE: The formation of protein corona (PC) will affect the operation of nanoparticles (NPs) in vivo. Since there are many proteins in the blood, it is impossible to completely overcome the formation of PC. Therefore, the use of PCs to deliver drug is the best choice. De-opsonins adsorbed on NPs can reduce macrophage phagocytosis and cytotoxicity of NPs, and prolong their circulation in blood. Albumin, apolipoprotein and transferrin are typical de-opsonins. In present review, we mainly discuss how to optimize the delivery of nanoparticles through the formation of albumin corona, transferrin corona and apolipoprotein corona in vivo or in vitro.

Nanomaterials for cancer therapy: current progress and perspectives

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

Graphene Family Nanomaterials in Ocular Applications: Physicochemical Properties and Toxicity

Graphene family nanomaterials (GFNs) are rapidly emerging for ocular applications due to their outstanding physicochemical properties. Since the eyes are very sensitive organs and the contact between the eyes and GFNs in eye drops, contact lenses, intraocular drug delivery systems and biosensors and even the workers handling these nanomaterials is inevitable, it is necessary to investigate their ocular toxicities and physiological interactions with cells as well as their toxicity mechanisms. The toxicity of GFNs can be extremely affected by their physicochemical properties, including composition, size, surface chemistry, and oxidation level as well as dose and the time of exposure. Up to now, there are several studies on the in vitro and in vivo toxicity of GFNs; however, a comprehensive review on ocular toxicity and applications of GFNs is missing, and a knowledge about the health risks of eye exposure to the GFNs is predominantly unspecified. This review highlights the ocular applications of GFNs and systematically covers the most recent advances of GFNs' physicochemical properties, in vitro and in vivo ocular toxicity, and the possible toxicity mechanisms as well as provides some perspectives on the potential risks of GFNs in material development and biomedical applications.

Lateral size of graphene oxide determines differential cellular uptake and cell death pathways in Kupffer cells, LSECs, and hepatocytes

As a representative two-dimensional (2D) nanomaterial, graphene oxide (GO) has shown high potential in many applications due to its large surface area, high flexibility, and excellent dispersibility in aqueous solutions. These properties make GO an ideal candidate for bio-imaging, drug delivery, and cancer therapy. When delivered to the body, GO has been shown to accumulate in the liver, the primary accumulation site of systemic delivery or secondary spread from other uptake sites, and induce liver toxicity. However, the contribution of the GO physicochemical properties and individual liver cell types to this toxicity is unclear due to property variations and diverse cell types in the liver. Herein, we compare the effects of GOs with small (GO-S) and large (GO-L) lateral sizes in three major cell types in liver, Kupffer cells (KCs), liver sinusoidal endothelial cells (LSECs), and hepatocytes. While GOs induced cytotoxicity in KCs, they induced significantly less toxicity in LSECs and hepatocytes. For KCs, we found that GOs were phagocytosed that triggered NADPH oxidase mediated plasma membrane lipid peroxidation, which leads to PLC activation, calcium flux, mitochondrial ROS generation, and NLRP3 inflammasome activation. The subsequent caspase-1 activation induced IL-1β production and GSDMD-mediated pyroptosis. These effects were lateral size-dependent with GO-L showing stronger effects than GO-S. Amongst the liver cell types, decreased cell association and the absence of lipid peroxidation resulted in low cytotoxicity in LSECs and hepatocytes. Using additional GO samples with different lateral sizes, surface functionalities, or thickness, we further confirmed the differential cytotoxic effects in liver cells and the major role of GO lateral size in KUP5 pyroptosis by correlation studies. These findings delineated the GO effects on cellular uptake and cell death pathways in liver cells, and provide valuable information to further evaluate GO effects on the liver for biomedical applications.

Co-Sn-Cu oxides/graphene nanocomposites as green catalysts for preparing 1,8-dioxo-octahydroxanthenes and apoptosis-inducing agents in MCF-7 human breast cancer cells

In this work, Co-Sn-Cu oxides/graphene nanocomposite, 30-40 ± 0.5 nm in size, was synthesized by solid-state microwave irradiation. This method presents several advantages such as operational simplicity, fast, low cost, safe and energy efficient, and suitability for production of high purity of nanoparticles. Other advantages of this method are there is no need for the use of solvent, fuel, and surfactant. Co-Sn-Cu oxides/graphene nanocomposites have been characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, energy-dispersive X-ray spectroscopy, and UV-Vis spectroscopy. The synthesized nanocomposites were used as novel highly efficient catalysts for the synthesis of 1,8-dioxo-octahydroxanthenes at room temperature. The catalysts are recoverable and can be reused for six runs without loss of their activity. Also, the obtained nanocomposites exhibited significant anticancer activity against breast cancer cells and they could induce apoptosis in cancer cells.

CD47-mediated DTIC-loaded chitosan oligosaccharide-grafted nGO for synergistic chemo-photothermal therapy against malignant melanoma

Nano-graphene oxide (nGO), an effective drug nanocarrier, is used for simultaneous photothermal therapy (PTT) and near-infrared fluorescence imaging. Dacarbazine (DTIC) is used in the treatment of melanoma with limited clinical efficacy. PTT shows promise in the treatment of skin cancer. Herein, chitosan oligosaccharide (COS)-grafted nGO was further modified with CD47 antibody, and loaded DTIC was prepared using a versatile nanoplatform (nGO-COS-CD47/DTIC) for the treatment of melanoma as a synergistic targeted chemo-photothermal therapy. The in vitro results demonstrated that nGO-COS-CD47/DTIC nanocarriers have excellent biocompatibility, photothermal conversion efficiency, high targeting efficiency, fast drug release under NIR irradiation, and tumor cell killing efficiency. Notably, nGO-COS-CD47/DTIC plus NIR irradiation significantly promoted early cell apoptosis through the mitochondrial apoptosis pathway and exhibited a significant joint function of antitumor efficacy. The demonstrated nGO-COS-CD47/DTIC can provide a highly efficient malignant melanoma therapy using this multifunctional intelligent nanoplatform.

Raman and Fluorescence Enhancement Approaches in Graphene-Based Platforms for Optical Sensing and Imaging

The search for novel platforms and metamaterials for the enhancement of optical and particularly Raman signals is still an objective since optical techniques offer affordable, noninvasive methods with high spatial resolution and penetration depth adequate to detect and image a large variety of systems, from 2D materials to molecules in complex media and tissues. Definitely, plasmonic materials produce the most efficient enhancement through the surface-enhanced Raman scattering (SERS) process, allowing single-molecule detection, and are the most studied ones. Here we focus on less explored aspects of SERS such as the role of the inter-nanoparticle (NP) distance and the ultra-small NP size limit (down to a few nm) and on novel approaches involving graphene and graphene-related materials. The issues on reproducibility and homogeneity for the quantification of the probe molecules will also be discussed. Other light enhancement mechanisms, in particular resonant and interference Raman scatterings, as well as the platforms that allow combining several of them, are presented in this review with a special focus on the possibilities that graphene offers for the design and fabrication of novel architectures. Recent fluorescence enhancement platforms and strategies, so important for bio-detection and imaging, are reviewed as well as the relevance of graphene oxide and graphene/carbon nanodots in the field.

Can nanoparticles and nano‒protein interactions bring a bright future for insulin delivery?

Insulin therapy plays an essential role in the treatment of diabetes mellitus. However, frequent injections required to effectively control the glycemic levels lead to substantial inconvenience and low patient compliance. In order to improve insulin delivery, many efforts have been made, such as developing the nanoparticles (NPs)-based release systems and oral insulin. Although some improvements have been achieved, the ultimate results are still unsatisfying and none of insulin-loaded NPs systems have been approved for clinical use so far. Recently, nano‒protein interactions and protein corona formation have drawn much attention due to their negative influence on the in vivo fate of NPs systems. As the other side of a coin, such interactions can also be used for constructing advanced drug delivery systems. Herein, we aim to provide an insight into the advance and flaws of various NPs-based insulin delivery systems. Particularly, an interesting discussion on nano‒protein interactions and its potentials for developing novel insulin delivery systems is initiated.

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Insulin therapy plays essential roles in treating diabetes.

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Optimizing insulin delivery enhances insulin therapy.

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Nanoparticles are promising systems for delivery of insulin.

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Nano-protein interactions influence the delivery of nanoparticles.

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Nano-protein interactions can be used for advanced delivery of insulin.

A smart MnO2-doped graphene oxide nanosheet for enhanced chemo-photodynamic combinatorial therapy via simultaneous oxygenation and glutathione depletion

The combination of chemotherapy and photodynamic therapy provides a promising approach for enhanced tumor eradication by overcoming the limitations of each individual therapeutic modality. However, tumor is pathologically featured with extreme hypoxia together with the adaptable overexpression of anti-oxidants, such as glutathione (GSH), which greatly restricts the therapeutic efficiency. Here, a combinatorial strategy was designed to simultaneously relieve tumor hypoxia by self-oxygenation and reduce intracellular GSH level to sensitize chemo-photodynamic therapy. In our system, a novel multi-functional nanosystem based on MnO₂-doped graphene oxide (GO) was developed to co-load cisplatin (CisPt) and a photosensitizer (Ce6). With MnO₂ doping, the nanosystem was equipped with intelligent functionalities: (1) catalyzes the decomposition of H₂O₂ into oxygen to relieve the tumor hypoxia; (2) depletes GSH level in tumor cells, and (3) concomitantly generates Mn²⁺ to proceed Fenton-like reaction, all of which contribute to the enhanced anti-tumor efficacy. Meanwhile, the surface hyaluronic acid (HA) modification could facilitate the targeted delivery of the nanosystem into tumor cells, thereby resulting in amplified cellular toxicity, as well as tumor growth inhibition in nude mice model. This work sheds a new light on the development of intelligent nanosystems for synergistic combination therapy via regulating tumor microenvironment.

Current Advances in Black Phosphorus-Based Drug Delivery Systems for Cancer Therapy

Cancer has been one of the major threats to the lives of human beings for centuries. Traditional therapy is more or less faced with certain defects, such as poor targeting, easy degradation, high side effects, etc. Therefore, in order to improve the treatment efficiency of drugs, an intelligent drug delivery system (DDS) is considered as a promising solution strategy. Due to their special structure and large specific surface area, 2D materials are considered to be a good platform for drug delivery. Black phosphorus (BP), as a new star of the 2D family, is recommended to have the potential to construct DDS by virtue of its outstanding photothermal therapy (PTT), photodynamic therapy (PDT), and biodegradable properties. This tutorial review is intended to provide an introduction of the current advances in BP-based DDSs for cancer therapy, which covers topics from its construction, classified by the types of platforms, to the stimuli-responsive controlled drug release. Moreover, their cancer therapy applications including mono-, bi-, and multi-modal synergistic cancer therapy as well as the research of biocompatibility are also discussed. Finally, the current status and future prospects of BP-based DDSs for cancer therapy are summarized.

Recent advances in graphene-family nanomaterials for effective drug delivery and phototherapy

INTRODUCTION

Owing to the unique properties of graphene, including large specific surface area, excellent thermal conductivity, and optical absorption, graphene-family nanomaterials (GFNs) have attracted extensive attention in biomedical applications, particularly in drug delivery and phototherapy.

AREAS COVERED

In this review, we point out several challenges involved in the clinical application of GFNs. Then, we provide an overview of the most recent publications about GFNs in biomedical applications, including diverse strategies for improving the biocompatibility, specific targeting and stimuli-responsiveness of GFNs for drug delivery, codelivery of drug and gene, photothermal therapy, photodynamic therapy, and multimodal combination therapy.

EXPERT OPINION

Although the application of GFNs is still in the preclinical stage, rational modification of GFNs with functional elements or making full use of GFNs-based multimodal combination therapy might show great potential in biomedicine for clinical application.

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.

Polydopamine-based nanomaterials and their potentials in advanced drug delivery and therapy

Polydopamine (PDA) has shown great potentials in biomedical fields due largely to its unique physicochemical properties, including high photothermal transfer efficiency, excellent drug binding capacity, versatile adhesion ability, sensitive pH responsibility and great biocompatibility and biodegradability. These properties confer PDA-based nanoparticles the potentials either as the drug carriers for advanced drug delivery or as the bioactive agents for photothermal therapy, imaging and biosensing. This review aims to provide a comprehensive understanding of PDA, its polymerization mechanisms and the potentials of PDA-based nano-systems in treating various diseases, including cancer, diabetes, inflammation, bacterial infection and Parkinson's disease. In addition, the concerns of PDA in biomedical use are also discussed.

Elucidating the origin of the surface functionalization - dependent bacterial toxicity of graphene nanomaterials: Oxidative damage, physical disruption, and cell autolysis

Previous studies have shown that the toxicity of graphene nanomaterials (GNMs) to bacteria are related to the surface functionalization, however, the involved mechanisms are not fully understood. The present study aims to explore the toxic mechanisms of differentially functionalized GNMs to bacteria from the aspects of physical interaction, oxidative damage and cell autolysis. Three basic functionalization of GNMs including carboxylation (G-COOH), hydroxylation (G-OH) and amination (G-NH₂) were studied. G-COOH (66% viability vs CT group) and G-OH (54%) graphene showed higher toxicity to E. coli than G-NH₂ (96%) within 3 h at a concentration of 50 mg/L. The three materials showed distinct physical interaction modes with bacterial cells. G-COOH and G-OH contact with cell membrane via their sharp edges thus causing more damage than G-NH₂ which covered the bacteria attaching along the basal plane. The three GNMs showed similar radical generation capacities, thus the direct generation of radicals is not the mechanism causing the toxicity. Instead, the GNMs can oxidize the cellular antioxidant glutathione (GSH) thereby causing oxidative damage. The oxidative capacity follows the order: G-COOH > G-OH > G-NH₂, which correlated with the antibacterial activity. Cell autolysis, the degradation of cell wall component peptidoglycan, was found to be a new mechanism inducing the death of bacteria. G-COOH and G-OH caused more cell autolysis than G-NH₂, which accounts partially for the different toxicity of the three GNMs. The findings provide significant insights into the mechanism of GNMs toxicity to bacteria for not only the risk assessment of GNMs but also the design of graphene based antibacterial materials.

Protein corona formed in the gastrointestinal tract and its impacts on oral delivery of nanoparticles

The interaction of nanoparticles (NPs) with proteins and the formation of protein corona in the biological fluids are of great interest and significance for drug delivery. In the past decade, the corona formation in the blood and its impacts on the in vitro and in vivo fate of NPs has been well investigated and reviewed. Recently, more and more attention is paid to the nano-protein interactions taking place in the gastrointestinal tract (GIT) between the orally administered NPs and the digestive enzymes. The enzyme corona formed in the GIT can significantly affect the properties, gastrointestinal transit, and oral absorption of NPs. Since oral delivery is the most preferred delivery route, comprehensively understanding the corona formation in the GIT and its impacts on oral delivery NPs are of great importance. Herein, we aim to summarize the recent updates on the nano-protein interactions between NPs and digestive enzymes, and launch an interesting discussion on the potentials of using the digestive enzyme corona for the colon targeted delivery.

Potentials of nanotechnology in treatment of methicillin-resistant Staphylococcus aureus

Abuse of antibiotics has led to the emergence of drug-resistant pathogens. Methicillin-resistant Staphylococcus aureus (MRSA) was reported just two years after the clinical use of methicillin, which can cause severe infections with high morbidity and mortality in both community and hospital. The treatment of MRSA infection is greatly challenging since it has developed the resistance to almost all types of antibiotics. As such, it is of great significance and importance to develop novel therapeutic approaches. The fast development of nanotechnology provides a promising solution to this dilemma. Functional nanomaterials and nanoparticles can act either as drug carriers or as antibacterial agents for antibacterial therapy. Herein, we aim to provide a comprehensive understanding of the drug resistance mechanisms of MRSA and discuss the potential applications of some functionalized nanomaterials in anti-MRSA therapy. Also, the concerns and possible solutions for the nanomaterials-based anti-MRSA therapy are discussed.

Comparison of the effect of argon, hydrogen, and nitrogen gases on the reduced graphene oxide-hydroxyapatite nanocomposites characteristics

In this study, the effect of the argon, nitrogen, and hydrogen gases on the final properties of the reduced graphene oxide- hydroxyapatite nanocomposites synthesized by gas injected hydrothermal method was investigated. Four samples were synthesized, which in the first sample the pressure was controlled by volume change at a constant concentration. In subsequent samples, the pressure inside the autoclave was adjusted by the injecting gases. The initial pressure of the injected gases was 10 bar and the final pressure considered was 25 bar. The synthesized powders were consolidated at 950 °C and 2 MPa by spark plasma sintering method. The final samples were subjected to Vickers indentation analysis. The findings of this study indicate that the injection of argon, hydrogen, and nitrogen gases improved the mechanical properties of the nanocomposites. Injection of gases increased the crystallinity and particle size of hydroxyapatite, and this increase was greater for nitrogen gas than for others. Injection of these gases increased the rate of graphene oxide reduction and in this case the effect of nitrogen gas was greater than the others.

Polyethylene Glycol-Coated Graphene Oxide Loaded with Erlotinib as an Effective Therapeutic Agent for Treating Nasopharyngeal Cancer Cells

Introduction

Nasopharyngeal carcinoma (NPC) is a common cancer in southern China and Taiwan, and radiation therapy combined with or without chemotherapy is its mainstay treatment. Although it is highly sensitive to radiotherapy, local recurrence and distant metastasis remain difficult unsolved problems. In recent years, graphene oxide (GO) has been found to be a promising novel anticancer drug carrier. Here, we present our designed functionalized GO, polyethylene glycol-coated GO (GO-PEG), as a drug carrier, which was loaded with erlotinib and showed promising anticancer effects on NPC cells.

Methods

The effects of GO-PEG-erlotinib on the proliferation, migration, and invasion of NPC cells were investigated by WST-8 assay, wound healing assay, and invasion assay, respectively. RNA sequencing was conducted and analyzed to determine the molecular mechanisms by which GO-PEG-erlotinib affects NPC cells.

Results

Our results showed that GO-PEG-erlotinib reduced NPC cell viability in a dose-dependent manner and also inhibited the migration and invasion of NPC cells. The RNA sequencing revealed several related molecular mechanisms.

Conclusion

GO-PEG-erlotinib effectively suppressed NPC cell proliferation, migration, and invasion, likely by several mechanisms. GO-PEG-erlotinib may be a potential therapeutic agent for treating NPC in the future.