Titania-Graphene Oxide Nanocomposite-Based Philadelphia-Positive Leukemia Therapy

Philadelphia-positive (Ph+) leukemia is a type of blood cancer also known as acute lymphoblastic leukemia (ALL), affecting 20-30% of adults diagnosed worldwide and having an engraved prognosis as compared to other types of leukemia. The current treatment regimens mainly rely on tyrosine kinase inhibitors (TKIs) and bone marrow transplants. To date, several generations of TKIs have been developed due to associated resistance and frequent relapse, with cardiovascular system anomalies being the most devastating complication. Nanotechnology has the potential to address these limitations by the targeted drug delivery and controlled release of TKIs. This study focused on the titanium dioxide (TiO2) and graphene oxide (GO) nanocomposite employment to load nilotinib and ponatinib TKIs for therapy of Ph+ leukemia cell line (K562) and Ba/F3 cells engineered to express BCR-ABL oncogene. Meanwhile, after treatment, the oncogene expressing fibroblast cells (Rat-1 P185) were evaluated for their colony formation ability under 3D conditions. To validate the nanocomposite formation, the TiO2-GO nanocomposites were characterized by scanning electron microscope, DLS, XRD, FTIR, zeta potential, EDX, and element mapping. The TKI-loaded TiO2-GO was not inferior to the free drugs after evaluating their effects by a cell viability assay (XTT), apoptosis induction, and colony formation inhibition. The cell signaling pathways of the mammalian target of rapamycin (mTOR), signal transducers and activators of transcription 5 (STAT5), and extracellular signal-regulated kinase (Erk1/2) were also investigated by Western blot. These signaling pathways were significantly downregulated in the TKI-loaded TiO2-GO-treated groups. Based on the findings above, we can conclude that TiO2-GO exhibited excellent drug delivery potential that can be used for Ph+ leukemia therapy in the future, subject to further investigations.

Recent advances in synergistic use of GQD-based hydrogels for bioimaging and drug delivery in cancer treatment

Graphene quantum dot (GQD) integration into hydrogel matrices has become a viable approach for improving drug delivery and bioimaging in cancer treatment in recent years. Due to their distinct physicochemical characteristics, graphene quantum dots (GQDs) have attracted interest as adaptable nanomaterials for use in biomedicine. When incorporated into hydrogel frameworks, these nanomaterials exhibit enhanced stability, biocompatibility, and responsiveness to external stimuli. The synergistic pairing of hydrogels with GQDs has created new opportunities to tackle the problems related to drug delivery and bioimaging in cancer treatment. Bioimaging plays a pivotal role in the early detection and monitoring of cancer. GQD-based hydrogels, with their excellent photoluminescence properties, offer a superior platform for high-resolution imaging. The tunable fluorescence characteristics of GQDs enable real-time visualization of biological processes, facilitating the precise diagnosis and monitoring of cancer progression. Moreover, the drug delivery landscape has been significantly transformed by GQD-based hydrogels. Because hydrogels are porous, therapeutic compounds may be placed into them and released in a controlled environment. The large surface area and distinct interactions of graphene quantum dots (GQDs) with medicinal molecules boost loading capacity and release dynamics, ultimately improving therapeutic efficacy. Moreover, GQD-based hydrogels' stimulus-responsiveness allows for on-demand medication release, which minimizes adverse effects and improves therapeutic outcomes. The ability of GQD-based hydrogels to specifically target certain cancer cells makes them notable. Functionalizing GQDs with targeting ligands minimizes off-target effects and delivers therapeutic payloads to cancer cells selectively. Combined with imaging capabilities, this tailored drug delivery creates a theranostic platform for customized cancer treatment. In this study, the most recent advancements in the synergistic use of GQD-based hydrogels are reviewed, with particular attention to the potential revolution these materials might bring to the area of cancer theranostics.

Graphene quantum dot-crafted nanocomposites: shaping the future landscape of biomedical advances

Graphene quantum dots (GQDs) are a newly developed class of material, known as zero-dimensional nanomaterials, with characteristics derived from both carbon dots (CDs) and graphene. GQDs exhibit several ideal properties, including the potential to absorb incident energy, high water solubility, tunable photoluminescence, good stability, high drug-loading capacity, and notable biocompatibility, which make them powerful tools for various applications in the field of biomedicine. Additionally, GQDs can be incorporated with additional materials to develop nanocomposites with exceptional qualities and enriched functionalities. Inspired by the intriguing scientific discoveries and substantial contributions of GQDs to the field of biomedicine, we present a broad overview of recent advancements in GQDs-based nanocomposites for biomedical applications. The review first outlines the latest synthesis and classification of GQDs nanocomposite and enables their use in advanced composite materials for biomedicine. Furthermore, the systematic study of the biomedical applications for GQDs-based nanocomposites of drug delivery, biosensing, photothermal, photodynamic and combination therapies are emphasized. Finally, possibilities, challenges, and paths are highlighted to encourage additional research, which will lead to new therapeutics and global healthcare improvements.

Functionalized heteroatom-doped carbon dots for biomedical applications: A review

Carbon nanoparticles (CDs) have recently drawn a great attention in (bio)chemical analysis, sensing and bioimaging owing to their photostability, water stability, minimal toxicity, biocompatibility and ease of surface functionalization. While the vast majority of CDs applications rely on exploiting their fluorescent properties, doping such nanomaterials with various elements has recently received increasing attention as an effective approach to modify their optoelectronic characteristics, introducing novel improved optical features such as phosphorescence, upconversion luminescence or multimodal imaging capabilities. This review article focuses in the recent advances on the synthesis of heteroatom-doped CDs, exhibiting distinctive features of high value for sensing and imaging, as well as various functionalization schemes developed for guided analyte labeling. Relevant applications in chemical sensing, bioimaging and disease therapy are here presented. A final section intends to provide an overview towards future developments of such emerging light-emitting nanomaterials in the design of future devices and strategies for (bio)analytical chemistry.

The Use of Crystalline Carbon-Based Nanomaterials (CBNs) in Various Biomedical Applications

This review study aims to present, in a condensed manner, the significance of the use of crystalline carbon-based nanomaterials in biomedical applications. Crystalline carbon-based nanomaterials, encompassing graphene, graphene oxide, reduced graphene oxide, carbon nanotubes, and graphene quantum dots, have emerged as promising materials for the development of medical devices in various biomedical applications. These materials possess inorganic semiconducting attributes combined with organic π-π stacking features, allowing them to efficiently interact with biomolecules and present enhanced light responses. By harnessing these unique properties, carbon-based nanomaterials offer promising opportunities for future advancements in biomedicine. Recent studies have focused on the development of these nanomaterials for targeted drug delivery, cancer treatment, and biosensors. The conjugation and modification of carbon-based nanomaterials have led to significant advancements in a plethora of therapies and have addressed limitations in preclinical biomedical applications. Furthermore, the wide-ranging therapeutic advantages of carbon nanotubes have been thoroughly examined in the context of biomedical applications.

Nanozymes and nanoflower: Physiochemical properties, mechanism and biomedical applications

Natural enzymes possess several drawbacks which limits their application in industries, wastewater remediation and biomedical field. Therefore, in recent years researchers have developed enzyme mimicking nanomaterials and enzymatic hybrid nanoflower which are alternatives of enzyme. Nanozymes and organic inorganic hybrid nanoflower have been developed which mimics natural enzymes functionalities such as diverse enzyme mimicking activities, enhanced catalytic activities, low cost, ease of preparation, stability and biocompatibility. Nanozymes include metal and metal oxide nanoparticles mimicking oxidases, peroxidases, superoxide dismutase and catalases while enzymatic and non-enzymatic biomolecules were used for preparing hybrid nanoflower. In this review nanozymes and hybrid nanoflower have been compared in terms of physiochemical properties, common synthetic routes, mechanism of action, modification, green synthesis and application in the field of disease diagnosis, imaging, environmental remediation and disease treatment. We also address the current challenges facing nanozyme and hybrid nanoflower research and the possible way to fulfil their potential in future.

Dye Degradation and Sulfur Oxidation of Methyl Orange and Thiophenol via Newly Designed Nanocomposite GQDs/NiSe-NiO Photocatalyst Under Homemade LED Light

Photocatalytic processes triggered by graphene-based photocatalysts under solar light have sparked interest as a new sort of instrument for solar chemical synthesis. Herein we investigated self-assembled graphene quantum dots (GQDs)/NiSe-NiO composite photocatalyst for organic transformation as well as dye degradation. The synthesized GQDs/NiSe-NiO composite photocatalyst has an excellent suitable band gap, high molar extinction coefficient, low toxicity and chemical/thermal stability. The GQDs/NiSe-NiO composite photocatalyst emerges as a new standard for sulfur oxidation and dye degradation reactions under homemade LED light with high yield.

Graphene quantum dots: A review on the effect of synthesis parameters and theranostic applications

The rising demand for early-stage diagnosis of diseases such as cancer, diabetes, neurodegenerative can be met with the development of materials offering high sensitivity and specificity. Graphene quantum dots (GQDs) have been investigated extensively for theranostic applications owing to their superior photostability and high aqueous dispersibility. These are attractive for a range of biomedical applications as their physicochemical and optoelectronic properties can be tuned precisely. However, many aspects of these properties remain to be explored. In the present review, we have discussed the effect of synthetic parameters upon their physicochemical characteristics relevant to bioimaging. We have highlighted the effect of particle properties upon sensing of biological molecules through 'turn-on' and 'turn-off' fluorescence and generation of electrochemical signals. After describing the effect of surface chemistry and solution pH on optical properties, an inclusive view on application of GQDs in drug delivery and radiation therapy has been given. Finally, a brief overview on their application in gene therapy has also been included.

Nature-Inspired Nanoflower Structures on Titanium Surface via Alkali Treatment for Biomedical Applications

Titanium based metallic biomaterials for orthopedic implant applications are often associated with biocompatibility problems which can be ameliorated via proper surface modification strategies. Improving the hydrophilic nature of the titanium surface offers an effective strategy to sort out such limitations by intensifying the cellular activity. Development of titania as well as titanate layers on the titanium surface via alkali treatment represents an effective strategy to improve the hydrophilicity of native titanium surface. Inspired from nature, in the present work, we report the formation of three-dimensional (3D) hierarchical nanoflowers resembling Gomphrena globosa flowers developed on commercially pure titanium (cp-Ti) surface via a facile alkali treatment technique. X-ray diffraction studies evidenced anatase and rutile phases of TiO2 confirming the development of titania on the surface. In addition to the TiO2 phase, presence of titanate (Na2Ti3O7) has also been observed as alkali treatment was conducted in NaOH solution. The hydrophilicity of the Ti surface has been enhanced after the alkali treatment as evidenced from wettability studies using static contact angle measurements. This increase in hydrophilicity is due to the enrichment of the surface by TiO2 and titanate and increased roughness of nanoflower surface based on classical Wenzel law. In addition, the alkali-treated surface demonstrated an increased polar surface energy beneficial for biocompatible surfaces.

Recent advances in nanoscale materials for antibody-based cancer theranostics

The quest for advanced management tools or options of various cancers has been on the rise to efficiently reduce their risks of mortality without the demerits of conventional treatments (e.g., undesirable side effects of the medications on non-target tissues, non-targeted distribution, slow clearance of the administered drugs, and the development of drug resistance over the duration of therapy). In this context, nanomaterials-antibody conjugates can offer numerous advantages in the development of cancer theranostics over conventional delivery systems (e.g., highly specific and enhanced biodistribution of the drug in targeted tissues, prolonged systemic circulation, low toxicity, and minimally invasive molecular imaging). This review comprehensively discusses and evaluates recent advances in the application of nanomaterial-antibody bioconjugates for cancer theranostics for the further advancement in the control of diverse cancerous diseases. Further, discussion is expanded to cover the various challenges and limitations associated with the design and development of nanomaterial-antibody conjugates applicable towards better management of cancer.

Biomarkers-based Biosensing and Bioimaging with Graphene for Cancer Diagnosis

At the onset of cancer, specific biomarkers get elevated or modified in body fluids or tissues. Early diagnosis of these biomarkers can greatly improve the survival rate or facilitate effective treatment with different modalities. Potential nanomaterial-based biosensing and bioimaging are the main techniques in nanodiagnostics because of their ultra-high selectivity and sensitivity. Emerging graphene, including two dimensional (2D) graphene films, three dimensional (3D) graphene architectures and graphene hybrids (GHs) nanostructures, are attracting increasing interests in the field of biosensing and bioimaging. Due to their remarkable optical, electronic, and thermal properties; chemical and mechanical stability; large surface area; and good biocompatibility, graphene-based nanomaterials are applicable alternatives as versatile platforms to detect biomarkers at the early stage of cancer. Moreover, currently, extensive applications of graphene-based biosensing and bioimaging has resulted in promising prospects in cancer diagnosis. We also hope this review will provide critical insights to inspire more exciting researches to address the current remaining problems in this field.

Ethylenediamine mediated luminescence enhancement of pollutant derivatized carbon quantum dots for intracellular trinitrotoluene detection: soot to shine

Vehicle-generated toxic pollutants are composed of gaseous smoke and particulate byproducts accumulated as a black substance at its exhaust. This particulate matter (soot) is utilized for the green synthesis of highly stable, non-toxic, environment friendly, carbon quantum dots (CQD). The CQDs are synthesized via the simple hydrothermal route in the absence (C1) and presence (C2) of oxidants. The as-synthesized CQDs are amine functionalized using ethylenediamine. The amine functionalized CQDs (C1N and C2N) are explored for trinitrotoluene detection. From transmission electron microscopy, the average size of C1 and C2 was found to be about 4.2 nm and 5.6 nm respectively. The incorporation of amine groups lead to an increase in quantum yields from 5.63% to 12.7% for C1 and from 3.25% to 8.48% for C2 QDs. A limit of detection (LOD) of 13 ppb was displayed by C1N while the LODs of 11 ppb and 4.97 ppb were delivered by C2N at λ ex 370 nm and λ ex 420 nm respectively. The Stern-Volmer constant for C1N is 2.02 × 106 M-1 while for C2N at λ ex 370 nm and λ ex 420 nm is 0.38 × 106 M-1 and 0.48 × 106 M-1 respectively. Furthermore, C1N presents high selectivity for TNT compared to C2N. Owing to their higher luminescence, C1N particles are successfully demonstrated for their applicability in intracellular TNT detection.

Carbon Nanomaterials in Optical Detection

Owing to their unique optical, electronic, mechanical, and chemical properties, flexible chemical modification, large surface coverage and ready cellular uptake, various carbon nanomaterials such as carbon nanotubes (CNTs), graphene and its derivatives, carbon dots (CDs), graphene quantum dots, fullerenes, carbon nanohorns (CNHs) and carbon nano-onions (CNOs), have been widely explored for use in optical detection. Most of them are based on fluorescence changes. In this chapter, we will focus on carbon nanomaterials-based optical detection applications, mainly including fluorescence sensing and bio-imaging. Moreover, perspectives on future exploration of carbon nanomaterials for optical detection are also given.

Effect of Ionic Compounds of Different Valences on the Stability of Titanium Oxide Colloids

Titanium oxide particles of various morphologies have been prepared for applications of scientific or industrial interest in recent decades. Besides development of novel synthetic routes and solid-state characterization of the obtained particles, colloidal stability of titanium oxide dispersions was the focus of numerous research groups due to the high importance of this topic in applications in heterogeneous systems. The influence of dissolved ionic compounds, including monovalent salts, multivalent ions and polyelectrolytes, on the charging and aggregation behaviour of titanium oxide materials of spherical and elongated structures will be discussed in the present review.

Semiconductorversusgraphene quantum dots as fluorescent probes for cancer diagnosis and therapy applications

This review provides a comparison of optical, chemical and biocompatibility properties of graphene and semiconductor quantum dots as fluorescent probes.

A metal-free composite photocatalyst of graphene quantum dots deposited on red phosphorus

A simple approach to enhance the photocatalytic activity of red phosphorus (P) was developed. A mechanical ball milling method was applied to reduce the size of red P and to deposit graphene quantum dots onto red P. The product was characterized by scanning electron microscopy, transmission electron microscopy, contact angle measurements, zeta-potential measurements, X-ray diffraction and UV-vis absorption spectroscopy. The product exhibited high visible-light-driven photocatalytic performance in the photodegradation of rhodamine B.

Influence of Protamine Functionalization on the Colloidal Stability of 1D and 2D Titanium Oxide Nanostructures

The colloidal stability of titanium oxide nanosheets (TNS) and nanowires (TiONW) was studied in the presence of protamine (natural polyelectrolyte) in aqueous dispersions, where the nanostructures possessed negative net charge, and the protamine was positively charged. Regardless of their shape, similar charging and aggregation behaviors were observed for both TNS and TiONW. Electrophoretic experiments performed at different protamine loadings revealed that the adsorption of protamine led to charge neutralization and charge inversion depending on the polyelectrolyte dose applied. Light scattering measurements indicated unstable dispersions once the surface charge was close to zero or slow aggregation below and above the charge neutralization point with negatively or positively charged nanostructures, respectively. These stability regimes were confirmed by the electron microscopy images taken at different polyelectrolyte loadings. The protamine dose and salt-dependent colloidal stability confirmed the presence of DLVO-type interparticle forces, and no experimental evidence was found for additional interactions (e.g., patch-charge, hydrophobic, or steric forces), which are usually present in similar polyelectrolyte-particle systems. These findings indicate that the polyelectrolyte adsorbs on the TNS and TiONW surfaces in a flat and extended conformation giving rise to the absence of surface heterogeneities. Therefore, protamine is an excellent biocompatible candidate to form smooth surfaces, for instance in multilayers composed of polyelectrolytes and particles to be used in biomedical applications.

Methotrexate-loaded nitrogen-doped graphene quantum dots nanocarriers as an efficient anticancer drug delivery system

Graphene quantum dots (GQDs) are new efficient nanomaterials used in therapeutic applications. In this study, blue fluorescent nitrogen-doped GQDs (N-GQDs) were synthesized by a hydrothermal method via pyrolisis of citric acid as the carbon source and urea as the nitrogen source. The existence of doped nitrogen in GQDs was confirmed by FTIR characterization. Here, for the first time, the N-GQDs were loaded with the anticancer drug, methotrexate (MTX), to prepare MTX-(N-GQDs) as an efficient drug delivery system. The establishment of the strong π-π stacking interaction between MTX and N-GQDs was confirmed by FTIR and UV-vis spectroscopies indicating successful loading of MTX to N-GQDs. The in-vitro cytotoxicity of MTX-(N-GQDs) on human breast cancer cells investigated through MTT assay suggested that the drug-free N-GQDs nanocarriers are highly biocompatible, whereas the MTX-loaded ones are more cytotoxic than the free MTX.

Bio-conjugation of graphene quantum dots for targeting imaging

We demonstrate GQD-based bio-conjugation. Targeted imaging can be achieved in both cells and tissue models with single or multi-color staining, showing universality for different kinds of biological models.

Synthesis of upconversion nanoparticles conjugated with graphene oxide quantum dots and their use against cancer cell imaging and photodynamic therapy

Multifunctional nanocomposite has a huge potential for cell imaging, drug delivery, and improving therapeutic effect with less side effects. To date, diverse approaches have been demonstrated to endow a single nanostructure with multifunctionality. Herein, we report the synthesis and application of core-shell nanoparticles composed with upconversion nanoparticle (UCNP) as a core and a graphene oxide quantum dot (GOQD) as a shell. The UCNP was prepared and applied for imaging-guided analyses of upconversion luminescence. GOQD was prepared and employed as promising drug delivery vehicles to improve anti-tumor therapy effect in this study. Unique properties of UCNPs and GOQDs were incorporated into a single nanostructure to provide desirable functions for cell imaging and drug delivery. In addition, hypocrellin A (HA) was loaded on GOQDs for photo-dynamic therapy (PDT). HA, a commonly used chemotherapy drug and a photo-sensitizer, was conjugated with GOQD by π-π interaction and loaded on PEGylated UCNP without complicated synthetic process, which can break structure of HA. Applying these core-shell nanoparticles to MTT assay, we demonstrated that the UCNPs with GOQD shell loaded with HA could be excellent candidates as multifunctional agents for cell imaging, drug delivery and cell therapy.

Photodynamic Graphene Quantum Dot: Reduction Condition Regulated Photoactivity and Size Dependent Efficacy

Prequenching and selective activation of photosensitizer (PS) are highly desired in photodynamic therapy (PDT) to avoid off-target effect due to nonspecific activation and poor targeting selectivity of PS. In this study, nanographene materials as a unique π-conjugated planar system for electronic transfer were employed as the robust platform for temporarily quenching of PS. Photosensitizer chlorin e6 (Ce6) was integrated onto planar structure of graphene quantum dot (GQD) or graphene oxide (GO) via a reduction cleavable disulfide linker. The formed hybrid nanosystem displayed considerable fluorescence quenching and slight phototoxicity, even under the condition of light irradiation, while the photoactivity of PS could be selectively recovered in the presence of the reducing agent. Compared with graphene oxide system with larger size (around 200 nm), GQD nanosystem exhibited significantly improved tumor accumulation via enhanced permeation and retention effect (EPR effect). The in vivo study demonstrated extremely effective suppression of tumor growth for the group treated with the GQD nanosystem with cleavable linker, revealing the promising application of the presented novel strategy.

Temperature dependent, shape variant synthesis of photoluminescent and biocompatible carbon nanostructures from almond husk for applications in dye removal

The effect of the carbonization temperature on the morphology and properties of synthesized water soluble photoluminescent carbon nanostructures from almond husks have been investigated.

Microwave assisted one-pot synthesis of graphene quantum dots as highly sensitive fluorescent probes for detection of iron ions and pH value

Recently, carbon nanomaterials have received considerable attention as fluorescent probes owing to their low toxicity, water solubility and stable photochemical properties. However, the development of graphene quantum dots (GQDs) is still on its early stage. In this work, GQDs were successfully synthesized by one-step microwave assisted pyrolysis of aspartic acid (Asp) and NH4HCO3 mixture. The as-prepared GQDs exhibited strongly blue fluorescence with high quantum yield up to 14%. Strong fluorescence quenching effect of Fe(3+) on GQDs can be used for its high selectivity detection among of general metal ions. The probe exhibited a wide linear response concentration range (0-50 μM) to Fe(3+) and the limit of detection (LOD) was calculated to be 0.26 μM. In addition, GQDs are also sensitive to the pH value in the range from 2 to 12 indicating a great potential as optical pH sensors. More importantly, the GQDs possess lower cellular toxicity and high photostability and can be directly used as fluorescent probes for cell imaging.

In-vitro cytotoxicity assessment of carbon-nanodot-conjugated Fe-aminoclay (CD-FeAC) and its bio-imaging applications

We have investigated the cytotoxic assay of Fe-aminoclay (FeAC) nanoparticles (NPs) and simultaneous imaging in HeLa cells by photoluminescent carbon nanodots (CD) conjugation. Non-cytotoxic, photostable, and CD NPs are conjugated with cationic FeAC NPs where CD NPs play a role in bio-imaging and FeAC NPs act as a substrate for CD conjugation and help to uptake of NPs into cancer cells due to positively charged surface of FeAC NPs in physiological media. As increase of CD-FeAC NPs loading in HeLa cell in vitro, it showed slight cytotoxicity at 1000 μg/mL but no cytotoxicity for normal cells up to concentration of 1000 μg/mL confirmed by two 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and neutral red (NR) assays, with further observations by 4',6-diamidino-2-phenylindole (DAPI) stained confocal microscopy images, possessing that CD-FeAC NPs can be used as potential drug delivery platforms in cancer cells with simultaneous imaging. Graphical abstract CD conjugation with organo-building blocks of delaminated FeAC NPs.

Modification of Structural and Luminescence Properties of Graphene Quantum Dots by Gamma Irradiation and Their Application in a Photodynamic Therapy

Herein, the ability of gamma irradiation to enhance the photoluminescence properties of graphene quantum dots (GQDs) was investigated. Different doses of γ-irradiation were used on GQDs to examine the way in which their structure and optical properties can be affected. The photoluminescence quantum yield was increased six times for the GQDs irradiated with high doses compared to the nonirradiated material. Both photoluminescence lifetime and values of optical band gap were increased with the dose of applied gamma irradiation. In addition, the exploitation of the gamma-irradiated GQDs as photosensitizers was examined by monitoring the production of singlet oxygen under UV illumination. The main outcome was that the GQDs irradiated at lower doses act as better photoproducers than the ones irradiated at higher doses. These results corroborate that the structural changes caused by gamma irradiation have a direct impact on GQD ability to produce singlet oxygen and their photostability under prolonged UV illumination. This makes low-dose irradiated GQDs promising candidates for photodynamic therapy.

Multifunctional Poly(L-lactide)-Polyethylene Glycol-Grafted Graphene Quantum Dots for Intracellular MicroRNA Imaging and Combined Specific-Gene-Targeting Agents Delivery for Improved Therapeutics

Photoluminescent (PL) graphene quantum dots (GQDs) with large surface area and superior mechanical flexibility exhibit fascinating optical and electronic properties and possess great promising applications in biomedical engineering. Here, a multifunctional nanocomposite of poly(l-lactide) (PLA) and polyethylene glycol (PEG)-grafted GQDs (f-GQDs) was proposed for simultaneous intracellular microRNAs (miRNAs) imaging analysis and combined gene delivery for enhanced therapeutic efficiency. The functionalization of GQDs with PEG and PLA imparts the nanocomposite with super physiological stability and stable photoluminescence over a broad pH range, which is vital for cell imaging. Cell experiments demonstrate the f-GQDs excellent biocompatibility, lower cytotoxicity, and protective properties. Using the HeLa cell as a model, we found the f-GQDs effectively delivered a miRNA probe for intracellular miRNA imaging analysis and regulation. Notably, the large surface of GQDs was capable of simultaneous adsorption of agents targeting miRNA-21 and survivin, respectively. The combined conjugation of miRNA-21-targeting and survivin-targeting agents induced better inhibition of cancer cell growth and more apoptosis of cancer cells, compared with conjugation of agents targeting miRNA-21 or survivin alone. These findings highlight the promise of the highly versatile multifunctional nanocomposite in biomedical application of intracellular molecules analysis and clinical gene therapeutics.

Recent applications of carbon nanomaterials in fluorescence biosensing and bioimaging

A review of recent applications of carbon nanomaterials in fluorescence biosensing and bioimaging.

Gram-scale synthesis of high-purity graphene quantum dots with multicolor photoluminescence

A gram-scale approach has been developed to prepare highly pure graphene quantum dots (GQDs) from Vulcan XC-72 carbon black refluxed with concentrated nitric acid using a home-built experimental system.

A graphene quantum dots based fluorescent sensor for anthrax biomarker detection and its size dependence

Graphene quantum dots (GQDs) with two different diameters were modified via hybridization with a EuIII–macromolecule complex, and their application as dual emission fluorescent sensors for detection of Bacillus anthracis spores was investigated.

A cancer-targeted drug delivery system developed with gold nanoparticle mediated DNA–doxorubicin conjugates

A targeted drug delivery system based on AuNPs and DNA was developed to treat neuroblastoma cancer. This system exhibits excellent specificity in delivering and releasing doxorubicin, and has great prospects in clinical applications.