Multifunctional Theranostics for Dual-Modal Photodynamic Synergistic Therapy via Stepwise Water Splitting

Development of iron oxide based-upconversion nanocomposites for cancer therapeutics treatment

Administration of therapeutic strategies alongside magnetic multifunctional nanocomposites has displayed improved cancer prognosis. However, the clinical use of this combination is limited owing to poor bioimaging performance, low biocompatibility, restricted tissue penetration in ultraviolet/visible regions, and low therapeutic efficacy of nanocomposites. To overcome these existing challenges, we designed iron oxide (Fe3O4)-based upconversion nanoparticles (UCNPs). Fe3O4 nanoparticles were synthesized via facile solvothermal method and incorporated into mesoporous silica (mS) layer (Fe3O4@mS). Fe3O4@mS nanoparticles were further decorated onto the surface of the UCNPs as a core material (UCNP-Fe3O4@mS, FMUP). Methotrexate (MTX) an efficient anticancer drug was loaded onto the mesoporous silica to produce FMUP-MTX nanocomposite. The FMUP nanocomposite displayed excellent photothermal therapy and showed 43% photothermal conversion efficiency. The designed nanocomposite has ability to decompose H2O2 to generates hydroxyl radical that promote chemodynamic therapy effect due to attribution of Fenton reaction. FMUP-MTX nanocomposite possessed improved chemotherapeutic performance under NIR laser irradiation. Further, T2-weighted magnetic resonance imaging performance of nanocomposite was observed. In vitro studies shown that cell viability was decreased to 25% under laser irradiation due to the therapeutic effect. In vivo studies exhibited that the FMUP-MTX nanocomposite inhibited the tumor growth with the laser irradiation. Therefore, these nanocomposites can be considered as a promising candidate for cancer therapeutics treatment.

Enhancement of carbamazepine photodegradation using hybrid of phosphorescent carbon dots coupled with highly porous TiO2 photocatalyst

This study focuses on harnessing the synergistic effects between titanium oxide (TiO2) and carbon dots (CDs) to enhance the photocatalytic performance of TiO2. The work describes the synthesis of carbon dots exhibiting fluorescence (CDs) or phosphorescence (PhCDs), as well as the preparation of the TiO2 hybrid. Structural and textural measurements (X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 sorption isotherms) were conducted to elucidate the compositional and morphological changes induced by the incorporation of CDs into a matrix. Spectroscopic analyses revealed a shift of the absorption edge and range into the visible region of the CDs@TiO2 hybrid compared with pure TiO2. Infrared (IR) and Raman spectroscopy revealed the presence of diverse bonds associated with functional groups on the surface of the dots, enabling control over the spectroscopic properties of the resulting hybrids. Photocatalytic assessments demonstrated an enhancement in the PhCDs@TiO2 hybrid activity compared with pure TiO2. The proposed mechanism for the increase in photocatalytic activity in PhCDs@TiO2 is based on the slowdown of carrier recombination, which is linked to the confinement of electrons within traps located below the conduction band. The demonstrated enhancement in photocatalytic activity holds promise for the more effective decomposition of organic compounds in water, while the utilization of carbon dots unveils new avenues for modifying existing photocatalysts.

Progress on Carbon Dots with Intrinsic Bioactivities for Multimodal Theranostics

Carbon dots (CDs) with intrinsic bioactivities are candidates for bioimaging and disease therapy due to their diverse bioactivities, high biocompatibility, and multiple functionalities in multimodal theranostics. It is a multidisciplinary research hotspot that includes biology, physics, materials science, and chemistry. This progress report discusses the CDs with intrinsic bioactivities and their applications in multimodal theranostics. The relationship between the synthesis and structure of CDs is summarized and analyzed from a material and chemical perspective. The bioactivities of CDs including anti-tumor, antibacterial, anti-inflammatory etc. are discussed from biological points of view. Subsequently, the optical and electronic properties of CDs that can be applied in the biomedical field are summarized from a physical perspective. Based on the functional review of CDs, their applications in the biomedical field are reviewed, including optical diagnosis and treatment, biological activity, etc. Unlike previous reviews, this review combines multiple disciplines to gain a more comprehensive understanding of the mechanisms, functions, and applications of CDs with intrinsic bioactivities.

Nanozymes: a promising solution for dental antibacterial applications

Dental diseases pose significant public health challenges globally, affecting millions with conditions exacerbated by microbial-induced inflammation. Traditional natural enzymes, despite their antibacterial and anti-inflammatory capabilities, are limited by operational stability and environmental sensitivity. This review explores the revolutionary realm of nanozyme-artificial enzymes made from nanomaterials-which offer enhanced stability, cost-effectiveness, and ease of modification. We discuss the advent of nanozymes since their first recognition in 2007, emphasizing their enzyme-mimicking capabilities and applications in dental medicine, particularly for dental caries, pulpitis, periodontitis and peri-implantitis. This paper presents a comprehensive analysis of nanozymes' classification, mechanisms, and emerging applications, shedding light on their potential to revolutionize dental antibacterial treatments and addressing current challenges and future perspectives in their development.

Near-Infrared Driven Gold Nanoparticles-Decorated g-C3N4/SnS2 Heterostructure through Photodynamic and Photothermal Therapy for Cancer Treatment

Background

Phototherapy based on photocatalytic semiconductor nanomaterials has received considerable attention for the cancer treatment. Nonetheless, intense efficacy for in vivo treatment is restricted by inadequate photocatalytic activity and visible light response.

Methods

In this study, we designed a photocatalytic heterostructure using graphitic carbon nitride (g-C3N4) and tin disulfide (SnS2) to synthesize g-C3N4/SnS2 heterostructure through hydrothermal process. Furthermore, Au nanoparticles were decorated in situ deposition on the surface of the g-C3N4/SnS2 heterostructure to form g-C3N4/SnS2@Au nanoparticles.

Results

The g-C3N4/SnS2@Au nanoparticles generated intense reactive oxygen species radicals under near-infrared (NIR) laser irradiation through photodynamic therapy (PDT) pathways (Type-I and Type-II). These nanoparticles exhibited enhanced photothermal therapy (PTT) efficacy with high photothermal conversion efficiency (41%) when subjected to 808 nm laser light, owing to the presence of Au nanoparticles. The in vitro studies have indicated that these nanoparticles can induce human liver carcinoma cancer cell (HepG2) apoptosis (approximately 80% cell death) through the synergistic therapeutic effects of PDT and PTT. The in vivo results demonstrated that these nanoparticles exhibited enhanced efficient antitumor effects based on the combined effects of PDT and PTT.

Conclusion

The g-C3N4/SnS2@Au nanoparticles possessed enhanced photothermal properties and PDT effect, good biocompatibility and intense antitumor efficacy. Therefore, these nanoparticles could be considered promising candidates through synergistic PDT/PTT effects upon irradiation with NIR laser for cancer treatment.

Near-infrared-driven upconversion nanoparticles with photocatalysts through water-splitting towards cancer treatment

Water splitting is promising, especially for energy and environmental applications; however, there are limited studies on the link between water splitting and cancer treatment. Upconversion nanoparticles (UCNPs) can be used to convert near-infrared (NIR) light to ultraviolet (UV) or visible (Vis) light and have great potential for biomedical applications because of their profound penetration ability, theranostic approaches, low self-fluorescence background, reduced damage to biological tissue, and low toxicity. UCNPs with photocatalytic materials can enhance the photocatalytic activities that generate a shorter wavelength to increase the tissue penetration depth in the biological microenvironment under NIR light irradiation. Moreover, UCNPs with a photosensitizer can absorb NIR light and convert it into UV/vis light and emit upconverted photons, which excite the photoinitiator to create H2, O2, and/or OH˙ via water splitting processes when exposed to NIR irradiation. Therefore, combining UCNPs with intensified photocatalytic and photoinitiator materials may be a promising therapeutic approach for cancer treatment. This review provides a novel strategy for explaining the principles and mechanisms of UCNPs and NIR-driven UCNPs with photocatalytic materials through water splitting to achieve therapeutic outcomes for clinical applications. Moreover, the challenges and future perspectives of UCNP-based photocatalytic materials for water splitting for cancer treatment are discussed in this review.

Tunable Zeolitic Imidazolate Framework-8 Nanoparticles for Biomedical Applications

Zeolite imidazole framework-8 (ZIF-8) is the most prestigious one among zeolitic imidazolate framework (ZIF) with tunable dimensions and unique morphological features. Utilizing its synthetic adjustability and structural regularity, ZIF-8 exhibits enhanced flexibility, allowing for a wide range of functionalities, such as loading of nanoparticle components while preserving biomolecules activity. Extensive efforts are made from investigating synthesis techniques to develop novel applications over decades. In this review, the development and recent progress of various synthesis approaches are briefly summarized. In addition, its interesting properties such as adjustable porosity, excellent thermal, and chemical stabilities are introduced. Further, five representative biomedical applications are highlighted based on above physicochemical properties. Finally, the remaining challenges and offered insights into the future outlook are also discussed. This review aims to understand the co-relationships between structures and biomedical functionalities, offering the opportunity to construct attractive materials with promising characteristics.

Carbon dots and composite materials with excellent performances in cancer-targeted bioimaging and killing: a review

Carbon dots (CDs) are nanomaterials with excellent properties, including good biocompatibility, small size, ideal photoluminescence and surface modification, and are becoming one of the most attractive nanomaterials for the imaging, detection and treatment of tumors. Based on these advantages, CDs can be combined other materials to obtain composite particles with improved, even new, performance, mainly in photothermal and photodynamic therapies. This paper reviews the research progress of CDs and their composites in targeted tumor imaging, detection, diagnosis, drug delivery and tumor killing. It also discusses and proposes the challenges and perspectives of their future applications in these fields. This review provides ideas for future applications of novel CD-based materials in the diagnosis and treatment of cancer.

Smart nanostructures for targeted oxygen-producing photodynamic therapy of skin photoaging and potential mechanism

Background: Photodynamic therapy increases collagen and decreases solar fibrosis in photoaged skin; however, the efficacy of photodynamic therapy is limited in tissues with a hypoxic microenvironment. Methods: A novel autogenous oxygen-targeted nanoparticle, named MCZT, was synthesized based on the zeolitic imidazole framework material ZIF-8, methyl aminolevulinate, catalase and an anti-TRPV1 monoclonal antibody, and its effects on skin photoaging were investigated. Results: MCZT was successfully synthesized and showed uniform particle size, good dispersion, and excellent biocompatibility and safety. Moreover, MCZT effectively alleviated UV-induced inflammation, cellular senescence and apoptosis in HFF-1 cells. In in vivo models, MCZT ameliorated UV-evoked erythema and wrinkling, inflammation and oxidative stress, as well as the loss of collagen fibers and water, in the skin of mice. Conclusion: These findings suggest that MCZT holds promising potential for the treatment of skin photoaging.

Calcium-peroxide-mediated cascades of oxygen production and glutathione consumption induced efficient photodynamic and photothermal synergistic therapy

Photodynamic therapy (PDT) and photothermal therapy (PTT) are potent approaches to cancer treatment. However, the tumor microenvironment (TME) characterized by severe hypoxia and abundant glutathione (GSH) significantly reduces the effectiveness of PDT. In this study, we developed an oxidative stress amplifier CaO₂/ICG@ZIF-8, which was capable of self-sufficient O₂ delivery and GSH depletion to enhance PDT and PTT synergistic therapy. We utilized ZIF-8 as nanocarriers that when loaded with CaO₂ and indocyanine green (ICG) form CaO₂/ICG@ZIF-8 nanoparticles, which exhibit a uniform particle size distribution and a hydrated particle size of about 215 nm. CaO₂ reacts with water under acidic conditions to produce O₂ so CaO₂/ICG@ZIF-8 has an excellent O₂ supply capacity, which is essential for PDT. Moreover, CaO₂/ICG@ZIF-8 also reacts with GSH to form glutathione disulfides (GSSH), enhancing the therapeutic outcome of PDT by preventing the consumption of local ractive oxygen species. Beyond that, CaO₂/ICG@ZIF-8 can produce strong hyperthermia with a photothermal conversion efficiency of about 44%, which is exceedingly appropriate for PTT. Owing to its augmentation, PTT/PDT mediated by CaO₂/ICG@ZIF-8 demonstrates intense tumor inhibitory effects in both in vitro and in vivo studies. Notably, the Zn and Ca generated by CaO₂/ICG@ZIF-8 degradation are essential elements for the body, so CaO₂/ICG@ZIF-8 shows favorable safety. Altogether, the research provides a promising PDT/PTT synergistic therapeutic strategy for cancer and may show more medical applications in the future.

Afterglow Electrochemiluminescence from Nitrogen-Deficient Graphitic Carbon Nitride

Almost all current electrochemiluminescent reagents require real-time electrochemical stimulation to emit light. Here, we report a novel electrochemiluminescent reagent, nitrogen-deficient graphitic carbon nitride (CNx), that can emit afterglow electrochemiluminescence (ECL) after cessation of electric excitation. CNx obtained by post-thermal treatment of graphitic carbon nitride (CN) with KSCN has a cyanamide group and a nitrogen vacancy, which created defects to trap electrically injected electrons. The trapped electrons can slowly release and react with coreactants to emit light with longevity. The cathodic afterglow ECL lasts for 70 s after pulsing the CNx nanosheet (CNxNS-1.6)-modified glassy carbon electrode at -1.0 V for 20 s in 2.0 M PBS containing 1 mM K2S2O8. The afterglow ECL mechanism is revealed by investigation of its influencing factors and ECL wavelength. The discovery of afterglow ECL may open a new doorway for new significant applications of the ECL technique and provide a deeper understanding of the structure-property relationships of CN.

Effective modification of photocatalytic and piezocatalytic performances for poly(heptazine imide) by carbon dots decoration

As the high-crystalline phase of carbon nitride, poly(heptazine imide) (PHI) has attracted much attention in recent years, considering the more effective light absorption, better charge carrier behavior, and higher surface area of PHI compared with its counterpart with a melon structure that is commonly synthesized through thermal polymerization. Nevertheless, exploring effective strategies to further improve the performance of PHI is still highly desirable. In this work, it is revealed that the photocatalytic as well as piezocatalytic performances of PHI are greatly promoted by coupling with carbon dots (CDots) through a facile ultrasonication process. Detailed structure characterizations indicate that a very low content of CDots (0.05%) decoration can double the light absorbance and achieve the efficient separation and transfer of photogenerated charge carriers. The optimal photocatalytic hydrogen evolution rate of PHI/CDots is about 2.49 and 2.81 times that of PHI, under UV-Visible and visible light irradiation, respectively. Moreover, the piezocatalytic H₂O₂ generation and KMnO₄ degradation activities of PHI/CDots are around 2 times that of PHI. The results obtained in this work provide references for the modification of PHI and may inspire new strategies for the design of highly efficient carbonaceous photocatalysts.

Oxygen-Generating Hydrogels Overcome Tumor Hypoxia to Enhance Photodynamic/Gas Synergistic Therapy

Hypoxic environment is a bottleneck of photodynamic therapy (PDT) in tumor treatment, as oxygen is the critical substrate for photosensitivity reaction. Herein, a sustained oxygen supply system based on cerium nanoparticles and hydrogel (GHCAC) was explored for enhanced synergistic PDT and gas therapy. Ceria nanoparticles were prepared as a drug carrier by self-assembly mediated by hyaluronic acid (HA), a targeting for CD44 on cervical cancer cells, followed by photosensitizer and l-arginine (l-Arg) loading. Then, the GHCAC system was developed by incorporating a prepared nanocarrier (HCePA) and O₂-evolving agent calcium peroxide (CaO₂) into the hydrogel (Gel) developed by a poloxamer. Gel in the system could moderately infiltrate H₂O to react with CaO₂ and generate sustained oxygen using the catalase-like activity of HCePA. The system could efficiently alleviate hypoxia in tumor environments for up to 7 days, meeting the "once injection, repeat irradiation" strategy and enhanced PDT efficacy. Besides, the generated singlet oxygen (¹O₂) in the PDT process could also oxidize l-Arg into high concentrations of nitric oxide for synergistic gas therapy. The developed oxygen supplied and drug delivery Gel system is a new strategy for synergistic PDT/gas therapy to overcome cervical cancer.

Applications of nanocomposites based on zeolitic imidazolate framework-8 in photodynamic and synergistic anti-tumor therapy

Due to the limitations resulting from hypoxia and the self-aggregation of photosensitizers, photodynamic therapy (PDT) has not been applied clinically to treat most types of solid tumors. Zeolitic imidazolate framework-8 (ZIF-8) is a common metal-organic framework that has ultra-high porosity, an adjustable structure, good biocompatibility, and pH-induced biodegradability. In this review, we summarize the applications of ZIF-8 and its derivatives in PDT. This review is divided into two parts. In the first part, we summarize progress in the application of ZIF-8 to enhance PDT and realize theranostics. We discuss the use of ZIF-8 to avoid the self-aggregation of photosensitizers, alleviate hypoxia, increase the PDT penetration depth, and combine PDT with multi-modal imaging. In the second part, we summarize how ZIF-8 can achieve synergistic PDT with other anti-tumor therapies, including chemotherapy, photothermal therapy, chemodynamic therapy, starvation therapy, protein therapy, gene therapy, and immunotherapy. Finally, we highlight the challenges that must be overcome for ZIF-8 to be widely applied in PDT. To the best of our knowledge, this is the first review of ZIF-8-based nanoplatforms for PDT.

Recent Advances in the Application and Mechanism of Carbon Dots/Metal-Organic Frameworks Hybrids in Photocatalysis and the Detection of Environmental Pollutants

Metal-organic frameworks (MOFs) are a class of crystalline porous materials with simple synthesis conditions, large specific surface area, structural diversity, and a wide range of interesting properties. The integration of MOFs with other materials can provide new multifunctional composites that exhibit both component properties and new characteristics. In recent years, the integration of carbon dots (CDs) into MOFs to form composites has shown improved optical properties and fascinating new characteristics. This review focuses on the design and synthesis strategies of CDs@MOFs composites (including pore-confined synthesis, in situ encapsulation, post-synthesis modification and impregnation method) and their recent research progress in photocatalysis and detection of environmental pollutants. Both the achievements and problems are evaluated and proposed, and the opportunities and challenges of CDs@MOF composite are discussed.

Synthesis and Characterization of Zn-Organic Frameworks Containing Chitosan as a Low-Cost Inhibitor for Sulfuric-Acid-Induced Steel Corrosion: Practical and Computational Exploration

In this work, a Zn-benzenetricarboxylic acid (Zn@H3BTC) organic framework coated with a dispersed layer of chitosan (CH/Zn@H3BTC) was synthesized using a solvothermal approach. The synthesized CH/Zn@H3BTC was characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), thermal gravimetric analysis (TGA), and Brunauer, Emmett, and Teller (BET) surface area. The microscopic observation and the analysis of the BET surface area of CH/Zn@H3BTC nanocomposites indicated that chitosan plays an important role in controlling the surface morphology and surface properties of the Zn@H3BTC. The obtained findings showed that the surface area and particle size diameter were in the range of 80 m2 g-1 and 800 nm, respectively. The corrosion protection characteristics of the CH/Zn@H3BTC composite in comparison to pristine chitosan on duplex steel in 2.0 M H2SO4 medium determined by electrochemical (E vs. time, PDP, and EIS) approaches exhibited that the entire charge transfer resistance of the chitosan- and CH/Zn@H3BTC-composite-protected films on the duplex steel substrate was comparatively large, at 252.4 and 364.8 Ω cm2 with protection capacities of 94.1% and 97.8%, respectively, in comparison to the unprotected metal surface (Rp = 20.6 Ω cm2), indicating the films efficiently protected the metal from corrosion. After dipping the uninhabited and protected systems, the surface topographies of the duplex steel were inspected by FESEM. We found the adsorption of the CH/Zn@H3BTC composite on the metal interface obeys the model of the Langmuir isotherm. The CH/Zn@H3BTC composite revealed outstanding adsorption on the metal interface as established by MD simulations and DFT calculations. Consequently, we found that the designed CH/Zn@H3BTC composite shows potential as an applicant inhibitor for steel protection.

Fabrication of tailored rod-shaped carbon nitride, g-C3N4, decorated with MoSe2 flowers for the catalytic reduction of nitrophenol, organic dye degradation and biocompatibility studies

A facile hydrothermal approach was used to synthesize a self-assembled tailored rod-shaped g-C3N4 anchored with molybdenum diselenide (MoSe2) flowers.

Heterostructures Made of Upconversion Nanoparticles and Metal-Organic Frameworks for Biomedical Applications

Heterostructure nanoparticles (NPs), constructed by two single-component NPs with distinct nature and multifunctional properties, have attracted intensive interest in the past few years. Among them, heterostructures made of upconversion NPs (UCNPs) and metal-organic frameworks (MOFs) can not only integrate the advantageous characteristics (e.g., porosity, structural regularity) of MOFs with unique upconverted optical features of UCNPs, but also induce cooperative properties not observed either for single component due to their special optical or electronic communications. Recently, diverse UCNP-MOF heterostructures are designed and synthesized via different strategies and have demonstrated appealing potential for applications in biosensing and imaging, drug delivery, and photodynamic therapy (PDT). In this review, the synthesis strategies of UCNP-MOF heterostructures are first summarized, then the authors focus mainly on discussion of their biomedical applications, particularly as PDT agents for cancer treatment. Finally, the authors briefly outlook the current challenges and future perspectives of UCNP-MOF hybrid nanocomposites. The authors believe that this review will provide comprehensive understanding and inspirations toward recent advances of UCNP-MOF heterostructures.

Recent advances in in situ oxygen-generating and oxygen-replenishing strategies for hypoxic-enhanced photodynamic therapy

Cancer is a leading cause of death worldwide, accounting for an estimated 10 million deaths by 2020. Over the decades, various strategies for tumor therapy have been developed and evaluated. Photodynamic therapy (PDT) has attracted increasing attention due to its unique characteristics, including low systemic toxicity and minimally invasive nature. Despite the excellent clinical promise of PDT, hypoxia is still the Achilles' heel associated with its oxygen-dependent nature related to increased tumor proliferation, angiogenesis, and distant metastases. Moreover, PDT-mediated oxygen consumption further exacerbates the hypoxia condition, which will eventually lead to the poor effect of drug treatment and resistance and irreversible tumor metastasis, even limiting its effective application in the treatment of hypoxic tumors. Hypoxia, with increased oxygen consumption, may occur in acute and chronic hypoxia conditions in developing tumors. Tumor cells farther away from the capillaries have much lower oxygen levels than cells in adjacent areas. However, it is difficult to change the tumor's deep hypoxia state through different ways to reduce the tumor tissue's oxygen consumption. Therefore, it will become more difficult to cure malignant tumors completely. In recent years, numerous investigations have focused on improving PDT therapy's efficacy by providing molecular oxygen directly or indirectly to tumor tissues. In this review, different molecular oxygen supplementation methods are summarized to alleviate tumor hypoxia from the innovative perspective of using supplemental oxygen. Besides, the existing problems, future prospects and potential challenges of this strategy are also discussed.

Carbon nitride nanomaterials with application in photothermal and photodynamic therapies

Phototherapies offer treatment of tumors with high spatial selectivity. Photodynamic therapy (PDT) consists in the administration of a photosensitizer (PS) followed by local photoirradiation with light of specific wavelength. The excited states of the PS interact with biomolecules and molecular oxygen producing reactive oxygen species (ROS), which initiate cell death. Photothermal therapy (PTT) employs photothermal agents to harvest the energy from light and convert it into heat to produce a temperature increase of the surrounding environment leading to cell death. Due to their good biocompatibility and unique photophysical properties, carbon-based materials are suitable for application in PDT and PTT. In particular, graphitic carbon nitride (g-C₃N₄), is a low-cost, non-toxic, and environment-friendly material, which is currently being used in the development of new nanomaterials with application in PDT and PTT. This brief review includes recent advances in the development of g-C₃N₄-based nanomaterials specifically designed for achieving red-shifted band gaps with the aim of generating oxygen molecules via water splitting upon red light or NIR irradiation to tackle the hypoxic condition of the tumor area. Nanomaterials designed for theranostics, combining medical imaging applications with PDT and/or PTT treatments are also included. The recent developments of g-C₃N₄-nanomaterials containing lanthanide-based upconversion nanoparticles are also covered. Finally, g-C₃N₄-based nanomaterials employed in microwave induced photodynamic therapy, sonodynamic therapy, and magnetic hyperthermia are considered.

Nano-photosensitizers for enhanced photodynamic therapy

Photodynamic therapy (PDT) utilizes photosensitizers (PSs) together with irradiation light of specific wavelength interacting with oxygen to generate cytotoxic reactive oxygen species (ROS), which could trigger apoptosis and/or necrosis-induced cell death in target tissues. During the past two decades, multifunctional nano-PSs employing nanotechnology and nanomedicine developed, which present not only photosensitizing properties but additionally accurate drug release abilities, efficient response to optical stimuli and hypoxia resistance. Further, nano-PSs have been developed to enhance PDT efficacy by improving the ROS yield. In addition, nano-PSs with additive or synergistic therapies are significant for both currently preclinical study and future clinical practice, given their capability of considerable higher therapeutic efficacy under safer systemic drug dosage. In this review, nano-PSs that allow precise drug delivery for efficient absorption by target cells are introduced. Nano-PSs boosting sensitivity and conversion efficiency to PDT-activating stimuli are highlighted. Nano-PSs developed to address the challenging hypoxia conditions during PDT of deep-sited tumors are summarized. Specifically, PSs capable of synergistic therapy and the emerging novel types with higher ROS yield that further enhance PDT efficacy are presented. Finally, future demands for ideal nano-PSs, emphasizing clinical translation and application are discussed.

Nanoliposomes co-encapsulating Ce6 and SB3CT against the proliferation and metastasis of melanoma with the integration of photodynamic therapy and NKG2D-related immunotherapy on A375 cells

Purpose. To overcome the insufficiency of conventional photodynamic therapy (PDT) for treating metastatic melanoma, the combination of smart nanoparticles and PDT with immunotherapy was used to achieve a higher efficiency by accumulating more photosensitizers in tumor areas and triggering stronger immune responses against tumors after PDT.Methods. In this study, we designed a nanoliposome co-encapsulation of chlorin E6 (Ce6) and SB-3CT to realize significant antitumoral proliferation and metastasis efficacy after laser irradiation in A375 cells. The morphology, size distribution, and loading efficiency of Ce6-SB3CT@Liposome (Lip-SC) were characterized. The reactive oxygen species (ROS) generation and cytotoxicity were evaluated in A375 cells, and the mechanisms of natural killer (NK) cell-mediated killing were assessed.Results. Lip-SC showed good stability and was well-dispersed with a diameter of approximately 140 nm in phosphate-buffered saline. The nanoliposomes could accumulate in tumor areas and induce apoptosis in cancer cells upon 660 nm light irradiation, which could trigger an immune response and induce the expression of NK group 2 member D (NKG2D) ligands. The subsequently released SB-3CT could further activate NK cells effectively and strengthen the immune system by inhibiting the shedding of soluble NKG2D ligands.Discussion. Taken together, the synergistic effects of SB-3CT on nanoliposomes for Ce6-mediated PDT were analyzed in detail to provide a new platform for future anti-melanoma treatment.

Photothermal photodynamic therapy and enhanced radiotherapy of targeting copolymer-coated liquid metal nanoparticles on liver cancer

The maximized therapeutic efficacy in tumor treatment can be achieved with combination therapy. Herein, a metronidazole (MN) and RGD peptides were linked with the copolymer chains of polyacrylic acid (PAA) and polyethylene glycol (PEG) by condensation and Michael addition reactions, respectively, named as RGD-PEG-PAA-MN. Subsequently, liquid-metal (LM) nanoparticles broken by ultrasonication were coated with modified copolymer, forming RGD-PEG-PAA-MN@LM nanoparticles. These nanoparticles with the degradation under an acidic condition could target to tumor cells, and LM of these composited nanoparticles could not only efficiently convert the photoenergy of near infrared (NIR) into thermal energy, but also produce more reactive oxygen species under NIR or X ray irradiation. Furthermore, MN in the composited nanoparticles could enhance their radiation sensitivity of tumor tissues with hypoxia condition. The synergic effect of these nanoparticles on cancer limitation after the sequential radiations of NIR and X ray was significantly higher than the single radiation. In the experiments of tumor bearing mice, the volume of the tumor in RGD-PEG-PAA-MN@LM group at 14th day after two radiations of NIR and X-ray were significantly smaller than LM group, and the tumor of RGD-PEG-PAA-MN@LM group at 14th day after two radiations almost disappeared, suggesting better synergistic effect of RGD-PEG-PAA-MN@LM nanoparticles on photothermal conversion, photodynamics under two irradiations and their enhanced sensitization of X-ray radiation. Our results indicated that the prepared nanoparticles would be applied in the combinational therapy of liver tumor by the photothermal, photodynamic and sensitized radiation.

The recent progress on metal-organic frameworks for phototherapy

Some infectious or malignant diseases such as cancers are seriously threatening the health of human beings all over the world. The commonly used antibiotic therapy cannot effectively treat these diseases within a short time, and also bring about adverse effects such as drug resistance and immune system damage during long-term systemic treatment. Phototherapy is an emerging antibiotic-free strategy to treat these diseases. Upon light irradiation, phototherapeutic agents can generate cytotoxic reactive oxygen species (ROS) or induce a temperature increase, which leads to the death of targeted cells. These two kinds of killing strategies are referred to as photodynamic therapy (PDT) and photothermal therapy (PTT), respectively. So far, many photo-responsive agents have been developed. Among them, the metal-organic framework (MOF) is becoming one of the most promising photo-responsive materials because its structure and chemical compositions can be easily modulated to achieve specific functions. MOFs can have intrinsic photodynamic or photothermal ability under the rational design of MOF construction, or serve as the carrier of therapeutic agents, owing to its tunable porosity. MOFs also provide feasibility for various combined therapies and targeting methods, which improves the efficiency of phototherapy. In this review, we firstly investigated the principles of phototherapy, and comprehensively summarized recent advances of MOF in PDT, PTT and synergistic therapy, from construction to modification. We expect that our demonstration will shed light on the future development of this field, and bring it one step closer to clinical trials.

Oxygen Self‐Sufficient Nanoplatform for Enhanced and Selective Antibacterial Photodynamic Therapy against Anaerobe‐Induced Periodontal Disease

The hypoxic microenvironment, continuous oxygen consumption, and poor excitation light penetration depth during antimicrobial photodynamic therapy (aPDT) tremendously hinder the effects on bacterial inactivation. Herein, a smart nanocomposite with oxygen‐self‐generation is presented for enhanced and selective antibacterial properties against anaerobe‐induced periodontal diseases. By encapsulating Fe3O4 nanoparticles, Chlorin e6 and Coumarin 6 in the amphiphilic silane, combined light (red and infrared) stimulated aPDT is realized due to the increased conjugate structure, the corresponding red‐shifted absorption, and the magnetic navigation performance. To address the hypoxic microenvironment problem, further modification of MnO2 nanolayer on the composites is carried out, and catalytical activity is involved for the decomposition of hydrogen peroxide produced in the metabolic processing, providing sufficient oxygen for aPDT in infection sites. Experiments in the cellular level and animal model proved that the rising oxygen content could effectively relieve the hypoxia in a periodontal pocket and enhance the ROS production, remarkably boosting aPDT efficacy. The increasing local level of oxygen also shows the selective inhibition of pathogenic and anaerobic bacteria, which determines the success of periodontitis treatment. Therefore, this finding is promising for combating anaerobic pathogens with enhanced and selective properties in periodontal diseases, even in other bacteria‐induced infections, for future clinical application.

Fluorescent Carbon Nano-onion as Bioimaging Probe

Concentrically arranged multilayered fullerenes exhibiting onion-like morphology are popularly known as carbon nano-onion (CNO) and are useful in bioimaging application. On the basis of the origin of the fluorescence, the CNO-based nanoprobes are classified into type I and type II. The type I CNO-based nanoprobe needs a secondary moiety such as organic dyes or an amine functionalization at its surface to induce the fluorescence. On the other hand, the emission in type II does not originate from such an external surface passivating agent. The CNO-based system not only shows structural similarity to the well-known multiwalled carbon nanotube but is also a bit more advantageous because of its low cytotoxicity. These features enable their prolonged use in the biological system for imaging purposes. In particular, we have covered the aspects of synthesis, surface functionalization, the origin of fluorescence, and biocompatibility. In addition, recent developments directed toward in vitro and in vivo imaging studies by utilizing CNO-based nanoprobes are summarized here.

Synthesis of MOFs/GO composite for corrosion resistance application on carbon steel

Two unreported metal-organic frameworks [Cu(6-Me-2,3-pydc)(1,10-phen)·7H2O] n (namely Cu-MOF) and [Mn2(2,2'-bca)2(H2O)2] n (namely Mn-MOF) were synthesized by a solvothermal method and their structures were characterized and confirmed by elemental analysis, X-ray single crystal diffraction, Fourier infrared spectroscopy and thermogravimetric analysis. Cu-MOF/graphene (Cu-MOF/GR), Cu-MOF/graphene oxide (Cu-MOF/GO), Mn-MOF/graphene (Mn-MOF/GR) and Mn-MOF/graphene oxide (Mn-MOF/GO) composite materials were successfully synthesized by a solvothermal method and characterized and analyzed by PXRD, SEM and TEM. In order to study the corrosion inhibition properties of the Cu-MOF/GR, Cu-MOF/GO, Mn-MOF/GR and Mn-MOF/GO composite materials on carbon steel, they were mixed with waterborne acrylic varnish to prepare a series of composite coatings to explore in 3.5 wt% NaCl solution by electrochemical measurements and results showed that the total polarization resistance of the 3% Cu-MOF/GO and 3% Mn-MOF/GO composite coatings on the carbon steel surface were relatively large, and were 55 097 and 55 729 Ω cm2, respectively, which could effectively protect the carbon steel from corrosion. After immersion for 30 days, the 3% Mn-MOF/GO composite still maintained high corrosion resistance, the |Z| values were still as high as 23 804 Ω cm2. Therefore, MOFs compounded with GO can produce a synergistic corrosion inhibition effect and improve the corrosion resistance of the coating; this conclusion is well confirmed by the adhesion capability test.

Tumor-targeting and imaging micelles for pH-triggered anticancer drug release and combined photodynamic therapy

Herein, we construct a charge - switchable polymer nano micelles poly (2-(hexamethyl eneimino) ethyl methacrylate) - b - poly (ethylene glycol) monomethyl ether methacrylate) - b - poly (diethyl enetriaminepentaacetic acid methacrylate) - b - poly (1-vinyl imidazole) - b - poly (4-vinyl phenylboronic acid) (PC7A-PEG-DTPA-VI-PBA) in different pH solutions. DOX released faster from micelles in a weakly acidic environment (pH 5.0) than at pH 7.4. In order to enhance the anti-tumor effect, the imidazole functional groups in the polymer were used to coordinate CdSeTe quantum dots (QDs) for photodynamic treatment (PDT). In addition, the surfaces of the micelles were further decorated with phenylboronic acidas a targeting group, using DTPA chelating ^99mTc for SPECT imaging.It has been successfully demonstrated that the nanoparticles have a good cumulative effect on the tumor site.The structure of the polymer was characterized by ¹HNMR. The morphology and particle size of the micelles were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The drug loading capacity (DLC) and drug loading efficiency (DLE) of the micelles were analyzed by ultraviolet visible spectroscopy. And the pH-sensitive drug release and cytotoxicity of the micelles were verified in vitro. In vitro experiments showed that the nano micelles were noncytotoxic to different cell lines, while DOX@CdSeTe@PC7A-PEG-DTPA-VI-PBA inhibited the proliferation and promoted the apoptosis of B16F10 cells. An in vivo study with C57BL tumor-bearing mice indicated that DOX@CdSeTe@PC7A-PEG-DTPA-VI-PBA nano micelles efficiently inhibited tumor growth. Results showed that the nano micelles had good pH responsibility and biocompatibility, and the loaded DOX could be released in the weak acidic environment of tumor cells, and it was expected to be a good drug delivery system.

Carbon Nitride Hollow Theranostic Nanoregulators Executing Laser-Activatable Water Splitting for Enhanced Ultrasound/Fluorescence Imaging and Cooperative Phototherapy

The limited efficacy of "smart" nanotheranostic agents in eradicating tumors calls for the development of highly desirable nanoagents with diagnostics and therapeutics. Herein, to surmount these challenges, we constructed an intelligent nanoregulator by coating a mesoporous carbon nitride (C₃N₄) layer on a core-shell nitrogen-doped graphene quantum dot (N-GQD)@hollow mesoporous silica nanosphere (HMSN) and decorated it with a P-PEG-RGD polymer, to achieve active-targeting delivery (designated as R-NCNP). Upon irradiation, the resultant R-NCNP nanoregulators exhibit significant catalytic breakdown of water molecules, causing a sustainable elevation of oxygen level owing to the C₃N₄ shell, which facilitates tumor oxygenation and relieves tumor hypoxia. The generated oxygen bubbles serve as an echogenic source, triggering tissue impedance mismatch, thereby enhancing the generation of an echogenicity signal, making them laser-activatable ultrasound imaging agents. In addition, the encapsulated photosensitizers and C₃N₄-layered photosensitizer are simultaneously activated to maximize the yield of ROS, actualizing a triple-photosensitizer hybrid nanosystem exploited for enhanced PDT. Intriguingly, the N-GQDs endow the R-NCNP nanoregulator with a photothermal effect for hyperthemia, making it exhibit considerable photothermal outcomes and infrared thermal imaging (IRT). Importantly, further analysis reveals that the polymer-modified R-NCNPs actively target specific tumor tissues and display a triple-modal US/IRT/FL imaging-assisted cooperative PTT/PDT for real-time monitoring of tumor ablation and therapeutic evaluation. The rational synergy of triple-model PDT and efficient PTT in the designed nanoregulator confers excellent anticancer effects, as evidenced by in vitro and in vivo assays, which might explore more possibilities in personalized cancer treatment.

A nano-photosensitizer based on covalent organic framework nanosheets with high loading and therapeutic efficacy

Photooxidation provides a promising strategy for photocatalysis, photodynamic therapy, and environmental protection. Unfortunately, most organic photosensitizers possess weak hydrophilicity and a π-π conjugated structure, leading to singlet oxygen self-quenching, poor loadability and therefore unsatisfactory photooxidation efficiency. Thus, dispersion of these photosensitizers within a two-dimensional porous covalent organic framework has become a feasible strategy to hinder their self-aggregation and augment their loading capacity. Here, we report a phthalocyanine-based photosensitizer loaded on covalent organic framework nanosheets. This nano-photosensitizer exhibits highly dispersed organic fluorescent phthalocyanines and a high loading capacity. The fabricated nanosheets restrict self-aggregation of photosensitizer molecules and enhance the photooxidation activity, which may offer a new paradigm for photooxidation and its multiple applications.

Pegylated carbon nitride nanosheets for enhanced reactive oxygen species generation and photodynamic therapy under hypoxic conditions

The application of photodynamic therapy (PDT) is of ever-increasing importance in the treatment of malignant tumors; however, there are several major constraints that make it impossible to achieve optimal therapeutic effects. Our objective is to develop a novel photosensitizing drug for skin cancer. In the experiment, we fabricated four-arm-poly ethylene glycol modified amino-rich graphite phase carbon nitride nanosheets (AGCN-PEG), which have good stability in physiological solution and show selective accumulation in tumor cells. Under hypoxic conditions, the AGCN-PEG induced PDT can effectively inhibit growth on A431 human epidermoid carcinoma cells in vivo and in vitro. What's more, after being combined with TMPyP4, the therapeutic effect of AGCN-PEG was greatly improved.

Fighting Hypoxia to Improve PDT

Photodynamic therapy (PDT) has drawn great interest in recent years mainly due to its low side effects and few drug resistances. Nevertheless, one of the issues of PDT is the need for oxygen to induce a photodynamic effect. Tumours often have low oxygen concentrations, related to the abnormal structure of the microvessels leading to an ineffective blood distribution. Moreover, PDT consumes O2. In order to improve the oxygenation of tumour or decrease hypoxia, different strategies are developed and are described in this review: 1) The use of O2 vehicle; 2) the modification of the tumour microenvironment (TME); 3) combining other therapies with PDT; 4) hypoxia-independent PDT; 5) hypoxia-dependent PDT and 6) fractional PDT.

Graphitic carbon nitride-based nanocomposites and their biological applications: a review

Quantum dots (QDs) have extensive application prospects in the fields of optics, magnetism, catalysis, and biomedicine. New carbon-doped QDs are currently being used in these research fields. Graphitic carbon nitride QDs (g-CNs) composed of only carbon and nitrogen have attracted attention because of their unique optical and catalytic properties. g-CNs have numerous electronic properties and can be used as photocatalytic modifiers in a wide range of applications in electrochemistry. Additionally, g-CNs also have biological potential and due to their chemical composition have extremely low toxicity; their blue light emission can be applied to biological imaging, and their appropriate energy level (2.7 eV) allows electrons to be deposited on their surface, which allows g-CNs to be used as photosensitizers in optical therapy. Finally, g-CNs can be combined with other nanomaterials to form composite materials, which can result in new advantages not seen in either of the materials alone. In this manuscript, we thoroughly report the most recent findings regarding the synthesis of g-CNs and their respective properties. We report the advantages of g-CNs conferred by their unique properties and their advantages for application in current biology and medicines.

Tumor Reoxygenation and Blood Perfusion Enhanced Photodynamic Therapy using Ultrathin Graphdiyne Oxide Nanosheets

Both diffusion-limited and perfusion-limited hypoxia are associated with tumor progression, metastasis, and the resistance to therapeutic modalities. A strategy that can efficiently overcome both types of hypoxia to enhance the efficacy of cancer treatment has not been reported yet. Here, it is shown that by using biomimetic ultrathin graphdiyne oxide (GDYO) nanosheets, both types of hypoxia can be simultaneously addressed toward an ideal photodynamic therapy (PDT). The GDYO nanosheets, which are oxidized and exfoliated from graphdiyne (GDY), are able to efficiently catalyze water oxidation to release O₂ and generate singlet oxygen (¹O₂) using near-infrared irradiation. Meanwhile, GDYO nanosheets also exhibit excellent light-to-heat conversion performance with a photothermal conversion efficiency of 60.8%. Thus, after the GDYO nanosheets are coated with iRGD peptide-modified red blood membrane (i-RBM) to achieve tumor targeting, the biomimetic GDYO@i-RBM nanosheets can simultaneously enhance tumor reoxygenation and blood perfusion for PDT. This study provides new insights into utilizing novel water-splitting materials to relieve both diffusion- and perfusion-limited hypoxia for the development of a novel therapeutic platform.

Highly Homogeneous Biotinylated Carbon Nanodots: Red-Emitting Nanoheaters as Theranostic Agents toward Precision Cancer Medicine

Very recent red-emissive carbon nanodots (CDs) have shown potential as near-infrared converting tools to produce local heat useful in cancer theranostics. Besides, CDs seem very appealing for clinical applications combining hyperthermia, imaging, and drug delivery in a single platform capable of selectively targeting cancer cells. However, CDs still suffer from dramatic dot-to-dot variability issues such that a rational design of their structural, optical, and chemical characteristics for medical applications has been impossible so far. Herein, we report for the first time a simple and highly controllable layer-by-layer synthesis of biotin-decorated CDs with monodisperse size distribution, well established polymeric shell thickness, and degree of surface functionalization, endowed with strong red luminescence and the ability to convert NIR light into heat. These CDs, henceforth named CDs-PEG-BT, consist of a carbonaceous core passivated with biotin-terminated PEG₂₀₀₀ chains, which we demonstrate as active targeting groups to recognize cancer cells. The CDs-PEG-BT are designed to efficiently incorporate a high amount of anticancer drugs such as irinotecan (16-28%) and to act as NIR-activated nanoheaters capable of triggering local hyperthermia and massive drug release inside tumors, thus provoking sudden and efficient tumor death. The potential of the irinotecan-loaded CDs-PEG-BT (CDs-PEG-BT@IT) in fluorescence imaging was studied on 2D cultures and on complex 3D spheroids mimicking in vivo tumor architectures, showing their capability of selectively entering cancer cells through biotin receptors overexpressed in cell membranes. The efficient anticancer effect of these CDs was thoroughly assessed on multicellular 3D spheroids and patient organoids (tumor-on-a-dish preclinical models) to predict the drug response in humans in view of personalized medicine applications. CDs-PEG-BT@IT have a smart combination of properties, which pave the way to their real-world use as anticancer theranostic agents for image-guided photothermal applications.

Protein-Induced Gold Nanoparticle Assembly for Improving the Photothermal Effect in Cancer Therapy

Gold nanoparticles (AuNPs) are promising photothermal agents for cancer therapy. However, the absorption of spherical AuNPs is weak in the desired tissue-penetrating near-infrared (NIR) window, resulting in low photothermal efficiency within this window. Here, we show that fibrous nanostructures assembled from spherical AuNPs since the templating effect of silk fibroin (SF) could red-shift the optical absorption to NIR and thus present improved photothermal efficiency within the NIR window. Specifically, negatively charged SF, a protein derived from Bombyx mori, was assembled into nanofibers due to the interaction with the positively charged AuNPs and concomitantly templated the AuNPs into fibrous nanostructures. The resultant AuNPs/SF nanofibers presented higher NIR light absorption at 808 nm and higher photothermal efficiency under 808 nm NIR irradiation than nonassembled AuNPs. In vitro and in vivo analyses proved that AuNPs/SF nanofibers could efficiently kill breast cancer cells and destruct breast cancer tumor tissues under one-time NIR irradiation for 6 min by photothermal therapy (PTT) but nonassembled AuNPs could not. This work suggests that the self-assembled AuNPs/SF nanofibers are effective photosensitizers for PTT, and biotemplated assembly of photothermal agents into highly ordered nanostructures is a promising approach to increasing the PTT efficiency.

Recent insights into near-infrared light-responsive carbon dots for bioimaging and cancer phototherapy

The current developments of NIR-responsive CDs and their applications in bioimaging and phototherapy are highlighted in this review.

AgBiS2-TPP nanocomposite for mitochondrial targeting photodynamic therapy, photothermal therapy and bio-imaging under 808 nm NIR laser irradiation

AgBiS₂ nanodots as an NIR light-excited photosensitizer produce a PDT effect, which is reported for the first time.

A Nd3+ sensitized upconversion nanosystem with dual photosensitizers for improving photodynamic therapy efficacy

The efficacy of photodynamic therapy (PDT) was greatly hindered by the use of a 980 nm laser with undesired overheating effects as well as low reactive oxygen species (ROS) yields.

Multifunctional hyaluronic acid-derived carbon dots for self-targeted imaging-guided photodynamic therapy

It is of vital importance to engineer the surface structures of carbon dots (CDs) to satisfy their practical biomedical applications, including imaging and treatment. In this work, one type of hyaluronic acid-derived CD (HA-CD) was synthesized via a facile one-step hydrothermal method using cancer cell-targeted HA as a precursor. The as-prepared HA-CDs were targeted actively toward CD44 receptor-overexpressing cancer cells because a partial HA structure remained on the HA-CD surface. Beyond this, HA-CDs can act as a novel photosensitizer, because they can generate O₂˙^- under 650 nm laser irradiation, and they also exhibit excellent blue photoluminescence emission. The in vitro results revealed that HA-CDs imaged selectively CD44-overexpressing cancer cells and inhibited their growth under 650 nm laser irradiation. Thus, HA-CDs can serve as a promising self-targeted imaging-guided photodynamic therapy (PDT) agent for cancer. The present research provides a promising new method to simply construct multifunctional CD-based targeted phototheranostic systems.

Honeycomb-Satellite Structured pH/H2O2-Responsive Degradable Nanoplatform for Efficient Photodynamic Therapy and Multimodal Imaging

The oxygen-deprived environment of a solid tumor is still great restriction in achieving an efficient photodynamic therapy (PDT). In this work, we developed a smart pH-controllable and H₂O₂-responsive nanoplatform with degradable property, which was based on honeycomb manganese oxide (hMnO₂) nanospheres loaded with Ce6-sensitized core-shell-shell structured up-conversion nanoparticles (NaGdF₄:Yb/Er,Tm@NaGdF₄:Yb@NaNdF₄:Yb) (abbreviated as hMUC). In the system, the speedy breakup of the as-prepared hMnO₂ nanostructures results in release of loaded Ce6-sensitized UCNPs under the condition of H₂O₂ in acid solution. When exposed to tissue-penetrable 808 nm laser, up-conversion nanoparticles (UCNPs) emit higher-energy visible photons which would be absorbed by Ce6 to yield cytotoxic reactive oxygen species (ROS), thus triggering PDT treatment naturally. Moreover, the in vitro and in vivo experiments demonstrate that hMUC sample with the honeycomb-satellite structure can serve as multimodal bioimaging contrast agent for self-enhanced upconversion luminescence (UCL), magnetic resonance imaging (MRI) and computed tomography (CT) imaging, indicating that the as-prepared hMUC could be used in imaging-guided diagnosis and treatment, which has a potential application in the PDT treatment of tumor.

Multivalent Interactions between 2D Nanomaterials and Biointerfaces

2D nanomaterials, particularly graphene, offer many fascinating physicochemical properties that have generated exciting visions of future biological applications. In order to capitalize on the potential of 2D nanomaterials in this field, a full understanding of their interactions with biointerfaces is crucial. The uptake pathways, toxicity, long-term fate of 2D nanomaterials in biological systems, and their interactions with the living systems are fundamental questions that must be understood. Here, the latest progress is summarized, with a focus on pathogen, mammalian cell, and tissue interactions. The cellular uptake pathways of graphene derivatives will be discussed, along with health risks, and interactions with membranes-including bacteria and viruses-and the role of chemical structure and modifications. Other novel 2D nanomaterials with potential biomedical applications, such as transition-metal dichalcogenides, transition-metal oxide, and black phosphorus will be discussed at the end of this review.