As a new family of two-dimensional (2D) nanomaterials, MXenes have recently attracted much attention because of high performance in versatile applications including energy storage and ...electrochemistry, but their specific application to biomedicine has been rarely reported, especially for theranostic nanomedicine, i.e., concurrent diagnostic imaging and therapy. This study shows for the first time surface engineering and functionalization of 2D Ti
3
C
2
MXene nanosheets by the integration of GdW
10
-based polyoxometalates (POMs). These multifunctional GdW
10
@Ti
3
C
2
composite nanosheets provide hyperthermal treatment with magnetic resonance (MR) and/or computed tomography (CT) imaging guidance toward tumor cells or xenografts. A tumor was effectively eradicated without further reoccurrence during the observation period. GdW
10
nanoclusters that were integrated onto the surface of Ti
3
C
2
nanosheets were demonstrated to serve as a contrast agent for contrast-enhanced CT and MR imaging based on their unique composition, thus showing the potential for diagnostic-imaging guidance and monitoring for tumor hyperthermia nanotherapy. The high
in vivo
biocompatibility of GdW
10
@Ti
3
C
2
composite nanosheets was demonstrated to guarantee their subsequent translation into a medical treatment. This study provides a novel strategy for broadening the biomedical applications of MXenes by surface engineering and multifunctionalization, which is expected to promote further exploration of biomedical applications of MXenes in nanotheranostics.
•A systematic review on chloride ingress and steel corrosion in RAC is provided.•Revealing the chloride transport mechanism and analysing the influencing factors.•Presenting modification methods for ...decreasing chloride ingress and steel corrosion in RAC.•Showing an outlook of further research on chloride ingress in RAC.
Chloride ingress and resulting steel corrosion are the main reasons leading to durability degradation. A body of literature on chloride transport and steel corrosion in recycled aggregate concrete (RAC) is currently available, but a systematic review has been lacking. This paper presents a critical review of chloride transport in RAC, and the induced steel corrosion behaviour and cracking patterns of reinforced RAC are introduced. Related modification methods are further discussed. The results showed that the incorporated recycled aggregate (RA) increased chloride ingress in RAC, and a time-dependent characteristic was observed for the chloride diffusion coefficient. The lower RA properties led to higher chloride ingress in preparing RAC when RA substitution rates were the same; the induced environmental damage accelerated chloride ingress in RAC. Incorporating RA increased the steel corrosion risk and shortened the initial corrosion time of reinforced RAC, and the cracking pattern of reinforced RAC was different from the cracking pattern of reinforced natural aggregate concrete. Removing and enhancing the adhered old mortar of RA improve the properties of RAC, and various modification methods can be employed to improve the resistance to chloride ingress and steel corrosion in RAC. In particular, a CO2-curing treatment, which is eco-friendly, is recommended for improving the RA and RAC properties. The study of chloride ingress and steel corrosion in ultra-high performance RAC and 3D-printed RAC should be a focus in further studies.
Enzymes with intracellular activity have significant potential to treat diseases. Protein nanoparticles (NPs) considerably enhance intracellular delivery of enzymes. We have previously shown that a ...Salmonella effector enzyme, AvrA, delivered by NPs is capable of modulating inflammatory signals in a murine dextran sulfate sodium (DSS) colitis model. The NPs were instilled intrarectally, limiting delivery to the distal colon. Localized intestinal delivery of protein therapeutics via the oral route is a highly attractive alternative approach. However, the harsh conditions in the gastrointestinal tract can severely reduce protein function. The approach described here is to deliver therapeutic protein NPs encapsulated within gastro-protective microparticles (MPs) made from alginate and chitosan that subsequently release NPs in the small intestine and colon. A flow focusing microfluidic device was used to form alginate droplets encapsulating protein NPs. Droplets were then simultaneously crosslinked with calcium and coated with chitosan. Protein NPs encapsulated within crosslinked alginate/chitosan MPs were protected and retained their activity after incubation in simulated gastric fluid (SGF). Subsequent incubation in simulated intestinal fluid (SIF) induced release of bioactive protein NPs. Oral administration of AvrA NPs encapsulated in alginate/chitosan MPs delivered protein to intestinal epithelia and reduced clinical and histological scores of inflammation in a murine DSS-induced colitis model. Altogether, NPs in alginate/chitosan MPs are a potential oral delivery vehicle for protein therapeutics.
Hollow mesoporous nanomaterials have gained tremendous attention in the fields of nanomedicine and nanobiotechnology. Herein, n-perfluoropentane (PFP)-encapsulated hollow mesoporous Prussian blue ...(HPB) nanocubes (HPB-PFP) with excellent colloidal stability have been synthesized for concurrent in vivo tumor diagnosis and regression. The HPB shell shows excellent photothermal conversion efficiency that can absorb near-infrared (NIR) laser light and convert it into heat. The generated heat can not only cause tumor ablation by raising the temperature of tumor tissue but also promote the continuous gasification and bubbling of encapsulated liquid PFP with low boiling point. These formed PFP bubbles can cause tissue impedance mismatch, thus apparently enhancing the signal of B-mode ultrasound imaging in vitro and generating an apparent echogenicity signal for tumor tissues of nude mice in vivo. Without showing observable in vitro and in vivo cytotoxicity, the designed biocompatible HPB-PFP nanotheranostics with high colloidal stability and photothermal efficiency are anticipated to find various biomedical applications in activated ultrasound imaging-guided tumor detection and therapy.
Nano-sized graphene oxide (GO) is functionalized with adipic acid dihydrazide to introduce amine groups, and then hyaluronic acid (HA) is covalently conjugated to GO by the formation of amide bonds. ...The resulting HA-grafted GO (GO–HA) has negligible hemolytic activity and very low cytotoxicity towards HeLa and L929 cells, and it can be effectively taken up by cancer cells through receptor-mediated endocytosis. The histological, hematological and biochemical analysis results suggest no perceptible toxicity of GO–HA in mice at a high exposure level of 10mgkg−1 and at an exposure time of up to 10days. Doxorubicin (DOX) can be efficiently loaded on the GO–HA, and the resulting GO–HA/DOX exhibits notable cytotoxicity to HeLa cells. The in vivo drug delivery capability of GO–HA is demonstrated by following the tumor growth in mice after intravenous administration of GO–HA/DOX. The results indicate that GO–HA can efficaciously deliver DOX to the tumors and suppress tumor growth.
Using eco-friendly recycled brick powder (RBP) derived from waste brick to prepare strain hardening cementitious composites (SHCC) provides a new way of recycling the construction and demolition ...waste (CDW), and the dosage of cement in SHCC can be decreased. This paper investigated the micro-properties and mechanical properties of SHCC containing RBP by a series of experiments. The results showed that RBP had typical characteristics of supplementary cementitious material (SCM). The addition of RBP increased the SiO
content and decreased the hydration products in cementitious materials; in this case, the mechanical properties of mortar decreased with increasing RBP replacements, and a linear relationship was observed between them. It was noticed that the adverse effect of RBP on the mechanical properties decreased with increasing PVA fiber content in mortar. For SHCC containing various RBP replacements, the ultimate load increased, and the ultimate displacement decreased with increasing curing days. When using RBP to replace cement by weight, the ultimate displacement increased with the addition of RBP. Meanwhile, there was no significant reduction in the ultimate load of SHCC. When using RBP to replace fly ash (FA) by weight, the incorporation of RBP decreased the ultimate displacement of SHCC, whereas the ultimate load was improved. For example, the ultimate load and displacement of SHCC with 54%RBP were 17.6% higher and 16.4% lower, respectively, than those of SHCC with 54% FA.
Multiwalled carbon nanotube/CoFe
2O
4 nanocomposites with superparamagnetic property and high hydrophilicity have been successfully synthesized by an
in situ solvothermal method at 180
°C for MRI and ...anticancer drug delivery applications.
Multiwalled carbon nanotube (MWCNT)/cobalt ferrite (CoFe
2O
4) magnetic hybrids were synthesized by a solvothermal method. The reaction temperature significantly affected the structure of the resultant MWCNT/CoFe
2O
4 hybrids, which varied from 6
nm CoFe
2O
4 nanoparticles uniformly coated on the nanotubes at 180
°C to agglomerated CoFe
2O
4 spherical particles threaded by MWCNTs and forming necklace-like nanostructures at 240
°C. Based on the superparamagnetic property at room temperature and high hydrophilicity, the MWCNT/CoFe
2O
4 hybrids prepared at 180
°C (MWCNT/CoFe
2O
4-180) were further investigated for biomedical applications, which showed a high
T
2 relaxivity of 152.8 Fe mM
−1
s
−1 in aqueous solutions, a significant negative contrast enhancement effect on cancer cells and, more importantly, low cytotoxicity and negligible hemolytic activity. The anticancer drug doxorubicin (DOX) can be loaded onto the hybrids and subsequently released in a sustained and pH-responsive way. The DOX-loaded hybrids exhibited notable cytotoxicity to HeLa cancer cells due to the intracellular release of DOX. These results suggest that MWCNT/CoFe
2O
4-180 hybrids may be used as both effective magnetic resonance imaging contrast agents and anticancer drug delivery systems for simultaneous cancer diagnosis and chemotherapy.
The utilization of recycled brick aggregate (RBA) and recycled brick powder (RBP) in cementitious materials helps the reclamation of clay brick waste in construction and demolition waste. This work ...studied the properties of cementitious materials with RBA as aggregate and RBP as supplementary cementitious material. The RBA has lower apparent density and higher water absorption than natural aggregate, and RBP with an irregular micro-structure contains high content of silicon and aluminum oxides and possesses excellent pozzolanic activity. Incorporating RBP decreases the fluidity and increases the setting time, but the incorporated RBP improves the pore structure and decreases the average pore diameter of cementitious materials, thereby decreasing the permeability. Utilizing RBA increases the drying shrinkage, while the incorporated RBP decreases the drying shrinkage of cementitious materials; the mortar with 50% RBA and 30% RBP has the lower drying shrinkage than the common mortar without RBA and RBP. Incorporating RBA and high-volume RBP decreases the mechanical strength, while there is no obvious decrease in the mechanical strength for the mortar with 50% RBA and 30% RBP. Moreover, the flexural strength to compressive strength ratio increases with RBA and RBP incorporating. Utilizing RBA increases the water transport, while the water transport properties decrease with the RBP incorporation; incorporating appropriate content of RBA and RBP can obtain the cementitious materials with low permeability. Particularly, a significant decrease in chloride ingress occurs with the substitution of RBP.
A novel in situ decomposition/reduction approach is developed to manufacture hollow core, magnetic, and mesoporous double‐shell nanostructures (HMMNSs) via in situ decomposition and reduction of a ...β‐FeOOH nanorod core and organosilicate‐incorporated silica‐shell precursor. The formed HMMNSs are then aminated by silanization for further covalent conjugation to rhodamine B isothiocyanate (RBITC) and poly(ethylene glycol) (PEG) chains. The resultant RBITC‐grafted and PEGylated nanocomposites (HMMNS–R/Ps) have excellent blood compatibility and very low cytotoxicity towards HeLa and MCF‐7 cells, and can be taken up by cancer cells effectively in a dose‐dependent manner, as confirmed by in vitro flow cytometry, confocal luminescence imaging, and magnetic resonance imaging (MRI) studies. In vivo MRI studies coupled with Prussian blue staining of slides from different organs show that the nanocomposites preferentially accumulate in liver and spleen after intravenous injection, which suggests a potential application of the nanocomposites as MRI contrast agents. Importantly, the HMMNS–R/P nanocomposites show high loading capacity for water‐insoluble anticancer drugs (docetaxel or camptothecin) owing to the presence of a large inner cavity and enhanced surface area and pore volume. Furthermore, the drug‐loaded nanocomposites exhibit greater cytotoxicity than the corresponding free drugs. These results confirm that the HMMNS–R/P nanocomposites are promising candidates for simultaneous bioimaging and drug delivery.
A hollow core, magnetic and mesoporous double‐shell nanostructure is manufactured using a novel in situ decomposition/reduction approach. The formed nanostructures are aminated by silanization for further covalent conjugation to rhodamine B isothiocyanate (RBITC) and poly(ethylene glycol) (PEG) chains, to construct a multifunctional platform for bioimaging and anticancer drug delivery.
Monodisperse silica‐coated manganese oxide nanoparticles (NPs) with a diameter of ∼35 nm are synthesized and are aminated through silanization. The amine‐functionalized core–shell NPs enable the ...covalent conjugation of a fluorescent dye, Rhodamine B isothiocyanate (RBITC), and folate (FA) onto their surface. The formed Mn3O4@SiO2(RBITC)–FA core–shell nanocomposites are water‐dispersible, stable, and biocompatible when the Mn concentration is below 50 µg mL−1 as confirmed by a cytotoxicity assay. Relaxivity measurements show that the core–shell NPs have a T1 relaxivity (r1) of 0.50 mM−1 s−1 on the 0.5 T scanner and 0.47 mM−1 s−1 on the 3.0 T scanner, suggesting the possibility of using the particles as a T1 contrast agent. Combined flow cytometry, confocal microscopy, and magnetic resonance imaging studies show that the Mn3O4@SiO2(RBITC)–FA nanocomposites can specifically target cancer cells overexpressing FA receptors (FARs). Findings from this study suggest that the silica‐coated Mn3O4 core–shell NPs could be used as a platform for bimodal imaging (both magnetic resonance and fluorescence) in various biological systems.
Monodisperse silica‐coated manganese oxide nanoparticles (NPs) are aminated through silanization. The amine‐functionalized core–shell NPs enable the covalent conjugation of a fluorescent dye, Rhodamine B isothiocyanate (RBITC), and folate (FA) onto their surface. These Mn3O4@SiO2(RBITC)–FA core–shell nanocomposites may find application in bimodal imaging (both magnetic resonance and fluorescence) in various biological systems.
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