Bioinspired Synthesis of Magnetic Nanoparticles Based on Iron Oxides Using Orange Waste and Their Application as Photo-Activated Antibacterial Agents

Photothermal effect of Ag nanoparticles deposited over poly(amidoamine) grafted carbon nanotubes

Biology-Oriented Design Strategies of AIE Theranostic Probes

The development of cancer photothermal therapies, many of which rely on photothermal agents, has received significant attention in recent years. In this work, various ligands‐stabilized magnetite (Fe3O4) particles are fabricated and utilized as a photothermal agents for in vivo tumor‐imaging‐guided photothermal therapy. Fe3O4 particles stabilized by macromolecular ligands as, e.g. polyethylene glycol (PEG), exhibit a superior and more stable photothermal effect compared to Fe3O4 particles stabilized by small molecules like citrate, due to their stronger ability of antioxidation. In addition, the photothermal effect of Fe3O4 particles is revealed to increase with size, which is attributed to the redshift of Vis‐NIR spectra. Fe3O4 particles injected intravenously into mice can be accumulated in the tumor by the application of an external magnetic field, as revealed by magnetic resonance imaging. In vivo photothermal therapy test of PEG‐stabilized Fe3O4 further achieves better tumor ablation effect. Overall, this study demonstrates efficient imaging‐guided photothermal therapy of cancer that is based on Fe3O4 particles of optimized size and with optimized ligands. It is expected that the ligand‐directed and size‐dependent photothermal effect will provide more approaches in the design of novel materials.

In this study silica- and alkoxysilane-coated ultrasmall superparamagnetic iron oxide (USPIO) particles were synthesized, and their ability to label immortalized progenitor cells for magnetic resonance imaging (MRI) was compared. USPIO particles were synthesized by coprecipitation of ferric and ferrous salts. Subsequently, the particles were coated with silica, (3-aminopropyl)trimethoxysilane (APTMS), and [N-(2-aminoethyl)-3-aminopropyl]trimethoxysilane (AEAPTMS). The size of the USPIO particles was about 10 nm without a significant increase in diameter after coating. The highest T2 relaxivity was achieved for silica-coated USPIO particles, 339.80 +/- 0.22 s-1 mM-1, as compared with APTMS- and AEAPTMS-coated ones, reaching 134.40 +/- 0.01 and 84.79 +/- 0.02 s-1 mM-1, respectively. No toxic effects on the cells could be detected by trypan blue, TUNEL, and MTS assays. Uptake of USPIO particles was evaluated by Prussian blue staining, transmission electron microscopy, T2-MR relaxometry, and mass spectrometry. It was found that cell uptake of the different USPIO particles increased for longer incubation times and higher doses. Maximum cellular iron concentrations of 42.1 +/- 4.0 pg/cell (silica-coated USPIO particles), 37.1 +/- 3.5 pg/cell (APTMS-coated USPIO particles), and 32.7 +/- 4.0 pg/cell (AEAPTMS-coated USPIO particles) were achieved after incubation of the cells with USPIO particles at a dose of 3 micromol/mL for 6 h. The decrease of the T2 relaxation time of the cell pellets was most pronounced for cells incubated with silica-coated USPIO particles followed by APTMS- and AEAPTMS-coated particles, respectively. In gelatin gels even small clusters of labeled cells were detected by 1.5 T MRI, and significant changes in the T2 relaxation times of the gels were determined for 10000 labeled cells/mL for all particles. In summary, as compared with APTMS- and AEAPTMS-coated particles, silica-coated USPIO particles provide the highest T2 relaxivity and most effectively reduce the T2 relaxation time of immortalized progenitor cells after internalization. This suggests silica-coated USPIO particles are most suited for cell labeling approaches in MRI.

The high production and market demand for citrus fruits can increase environmental waste. Most people do not use orange peel waste even though this peel contains bioactive compounds and phytochemicals that have the potential to form ZnO using the green synthesis method. This new research offers an environmentally friendly solution to reducing orange peel waste using abundant natural resources for nanotechnology applications. Therefore, this research aims to identify the phase of ZnO material and functional groups from orange peel extract. The extraction method of ZnO from Citrus sinensis orange peel uses green synthesis. The analysis in this research indicates that the sample has the phase of a zincite crystalline and a nanocrystalline size of 12.98 nm. The sample has an absorption peak at a wave number of 4000 – 400 cm-1 with functional groups indicating OH, C=C, Zn-OH, and Zn-O stretching vibration

Ultrasmall superparamagnetic iron oxides (USPIOs): a future alternative magnetic resonance (MR) contrast agent for patients at risk for nephrogenic systemic fibrosis (NSF)?

As one of the diseases with high morbidity and low cure rate in the world, cancer has always threatened the health of the public. However, due to the complexity, diversity and heterogeneity of the tumor, it is difficult to inhibit tumor recurrence and metastasis by relying on surgery, radiotherapy or chemotherapy. Photothermal therapy (PTT) is a cancer treatment by laser irradiation, which converts light energy into heat energy mediated by photothermal agents, and induces local tissue hyperthermia to treat cancer. And it has attracted widespread attention because of its non-specificity, high tumor ablation efficiency, and low toxic side effects on normal cells. However, the clinical transformation process of PTT is also severely limited by some disadvantages including the inconvenience of the delivery, distribution and metabolic process of the photothermal agent and the inaccurate and incomplete evaluation of the results of cancer treatment. The researchers have designed a variety of photothermal agents with multimodal imaging capabilities for cancer diagnosis and treatment. These imaging methods include thermal imaging (TI), photoacoustic (PA) imaging, photoluminescence (PL) imaging, magnetic resonance imaging (MRI), X-ray computed tomography (CT) imaging, and positron emission tomography (PET) imaging. And the imaging-guided cancer treatments have improved the accuracy of tumor visual treatments and greatly facilitated the clinical transformation of PTT. At present, the trend of cancer treatment development has gradually changed from monotherapy to combination therapy. Other therapies in combination with PTT include photodynamic therapy (PDT), chemotherapy, immunotherapy, radiotherapy (RT), sonodynamic therapy (SDT), and other PTT-related therapies. These combination therapies overcome tumor heterogeneity and complexity, reversing multidrug resistance, and reduce unnecessary side effects, and can more effectively achieve cancer diagnosis and treatment. This review summarizes the recent advances in multimodal imaging-guided PTT and multitherapies in combination with PTT for cancer diagnosis and treatment. For a single photothermal treatment, it is often difficult for researchers to effectively monitor the delivery, distribution, metabolism, and excretion of photothermal agents, and to accurately and dynamically track and evaluate the real-time therapeutic effects of tumors. Various strategies have been developed to solve the problems of single photothermal therapy. The new nano-platforms based on PTT-based multimodal imaging methods or therapies reviewed in this paper combine cancer diagnosis and treatment, and effectively overcome the shortcomings of single photothermal anti-tumor therapy, which is difficult to visualize tumors and lack of therapeutic efficiency to provide the development of new cancer diagnosis and treatment technologies new opportunities. Whether it is a single photothermal therapy or a combination of photothermal therapy and other methods, there is still a long way to go to study its therapeutic mechanism and further applications. The ultimate goal of these studies is to go to the clinic, cure the tumor, and benefit mankind. It is believed that with the rapid development of nanotechnology and nanomedicine, these problems will be gradually solved, and the photothermal anti-tumor combination therapy based on multimodal imaging will surely make new breakthroughs.

Questions such as biomolecular interactions, kinetics of enzymes, DNA conformational changes, cellular structures properties (among others) are addressed by characterizing the biological function of molecules. This function depends on their structure and their dynamic properties, and are usually studied with optical labels. A widely used technique for that purpose is fluorescence correlation spectroscopy (FCS) that adopts fluorophores as reporters of dynamic processes. However, photobleaching limits the observation time on the one hand, and saturation at high excitation intensities imposes constraints for the study of fast molecular processes on the other hand. Gold nanoparticles (NPs) are labels of particular interest to overcome these drawbacks due to their photostability, low cytotoxicity and their availability with biocompatible surface coatings. In addition, NPs have found widespread application in life sciences and medicine, such as labels for optical imaging, carriers for drug and gene delivery, targets for cancer cell imaging and phototherapy, and contrast agent for magnetic resonance imaging (MRI). These applications all require methods to characterize their behaviour in a biological environment. Medical use of NPs usually requires intravenous injection. Once NPs are introduced into the blood stream they become exposed to biomolecules in the plasma that form a so-called protein corona. Obviously, knowledge about this interaction is needed for a safe medical application of NPs. The uptake of NPs by cells depends mainly on this protein corona. It is thus very important to understand the structural and dynamic properties of the protein corona at the molecular level to judge the fate of NPs in the human body prior to clinical studies. We introduce Optical Coherence Correlation Spectroscopy (OCCS) which exploits the backscattered light of NPs illuminated by a broadband light source. Due to the measurement of a scattering signal, OCCS gives access to long time scales that are hardly accessible with FCS experiments. The signal acquisition is similar to Fourier-domain optical coherence microscopy (FDOCM) with a dark-field contrast. We present the theory of OCCS based on auto-correlation analysis. Numerical simulations were used to estimate the performance of our new spectroscopy method and to build an analytical model for the auto-correlation function for measuring the diffusion coefficient and concentration of NPs in solution. An application to the study of the protein corona on NPs is presented. The hydrodynamic radius of superparamagnetic iron oxide nanoparticles (SPIONs) with adsorbed bovine serum albumin (BSA) is measured under physiological conditions using OCCS.We also aimed at improving the detection of these NPs in highly scattering environments, for instance inside a cell. Photothermal optical lock-in OCCS (poli-OCCS) is proposed, which exploits the absorption properties of gold NPs to generate a specific signal due to the photothermal effect. Poli-OCCS is introduced and first proof-of-principle measurements with gold NPs are presented.

ABSTRACTThe type of death of biological tissue varies with temperature and is broadly classified as apoptosis and necrosis. A new treatment called photothermal therapy is being studied on this basis. Photothermal therapy is a treatment technique based on photothermal effects and has the advantage of not requiring incisions and, therefore, no bleeding. In this study, a numerical analysis of photothermal therapy for squamous cell carcinoma was performed. Photothermal agents used were gold nanoparticles, and the photothermal therapy effect was confirmed by changing the angle of the laser irradiating the tumor tissue. The effectiveness of photothermal therapy was quantitatively assessed on the basis of three apoptotic variables. Further, the volume fraction of gold nanoparticles in the tumor tissue and laser intensity with optimal therapeutic effect for different laser irradiation angles were studied. Thus, the findings of this study can aid the practical implementation of photothermal therapy in the future.

The synthesis, characterization, and applications of iron oxide nanorods have received attention in recent years. Even though there are several studies on the biological applications of iron oxide nanoparticles, recent studies have shown that rod-shaped iron oxides are effective in magnetic hyperthermia (MHT) as therapeutic technique to treat cancer. This review focused on the synthesis and encapsulation of magnetic iron oxide nanorods (MIONRs) and their use in (MHT) and photothermal therapy (PTT) for cancer cells. Among the synthetic methods that have been used to prepare MIONRs, some could be used to precisely control the particle size of the as-prepared magnetic iron oxide nanoparticles (MIONs), while others could be used to prepare monodisperse particles with uniform size distributions. Some of the results presented in this review showed that magnetic oxide nanorods are more potent in MHT than polyhedral-shaped MIONs. The review shows that mixtures of polyhedral- and rod-shaped MIONs resulted in 59 and 77% cell death, while monodisperse MIONRs resulted in 95% cell death. It could thus be concluded that, for magnetic iron oxide to be effective in MHT and PTT, it is important to prepare monodisperse magnetic oxide nanorods.

Insight into the photothermal therapeutic impacts of silica-coated iron oxide nanocomposites

Photothermal therapy (PTT) is a new treatment modality for tumors. However, the efficient delivery of photothermal agents into tumors remains difficult, especially in hypoxic tumor regions. In this study, an approach to deliver melanin, a natural photothermal agent, into tumors using genetically engineered bacteria for image-guided photothermal and immune therapy is developed. An Escherichia coli MG1655 is transformed with a recombinant plasmid harboring a tyrosinase gene to produce melanin nanoparticles. Melanin-producing genetically engineered bacteria (MG1655-M) are systemically administered to 4T1 tumor-bearing mice. The tumor-targeting properties of MG1655-M in the hypoxic environment integrate the properties of hypoxia targeting, photoacoustic imaging, and photothermal therapeutic agents in an "all-in-one" manner. This eliminates the need for post-modification to achieve image-guided hypoxia-targeted cancer photothermal therapy. Tumor growth is significantly suppressed by irradiating the tumor with an 808nm laser. Furthermore, strong antitumor immunity is triggered by PTT, thereby producing long-term immune memory effects that effectively inhibit tumor metastasis and recurrence. This work proposes a new photothermal and immune therapy guided by an "all-in-one" melanin-producing genetically engineered bacteria, which can offer broad potential applications in cancer treatment.

Photothermal therapy (PTT) has emerged as a promising strategy for the treatment of tumors. However, the intrinsic self-repair mechanism of cells and the nonspecific photothermal effect of photothermal agents can result in poor treatment outcomes and normal tissue injury. To address this issue, we developed a dual light activatable perylenediimide derivative (P-NO) for nitric oxide-enhanced PTT. P-NO can self-assemble into nanoparticles in aqueous solutions. The P-NO nanoparticles are capable of releasing both NO and a photothermal molecule (P-NH) upon green light irradiation. The simultaneous release of NO and P-NH activates the photothermal effect and inhibits cell protection autophagy, thereby improving the therapeutic efficacy of PTT under near-infrared (NIR) light. Moreover, the switch on of NIR fluorescence allows real-time monitoring of the release of P-NH. Remarkably, in a mouse subcutaneous tumor model, significant tumor ablation can be achieved following dual light activated photothermal gas therapy. This work offers a promising and straightforward approach to constructing activatable perylenediimide-based photothermal agents for enhancing the effectiveness of photothermal gas therapy.

Photodynamic therapy (PDT), as a minimally invasive and high‐efficiency anticancer approach, has received extensive research attention recently. Despite plenty of effort devoted to exploring various types of photodynamic agents with strong near‐infrared (NIR) absorbance for PDT and many encouraging progresses achieved in the area, effective and safe photodynamic photosensitizers with good biodegradability and biocompatibility are still highly expected. In this work, a novel nanocomposite has been developed by assembly of iron oxide (Fe3O4) nanoparticles (NPs) and Au nanoparticles on black phosphorus sheets (BPs@Au@Fe3O4), which shows a broad light absorption band and a photodegradable character. In vitro and in vivo assay indicates that BPs@Au@Fe3O4 nanoparticles are highly biocompatible and exhibit excellent tumor inhibition efficacy owing to a synergistic photothermal and photodynamic therapy mediated by a low‐power NIR laser. Importantly, BPs@Au@Fe3O4 can anticipatorily suppress tumor growth by visualized synergistic therapy with the help of magnetic resonance imaging (MRI). This work presents the first combination application of the photodynamic and photothermal effect deriving from black phosphorus nanosheets and plasmonic photothermal effect from Au nanoparticles together with MRI from Fe3O4 NPs, which may open the new utilization of black phosphorus nanosheets in biomedicine, optoelectronic devices, and photocatalysis.

A metal protoporphyrin-induced nano-self-assembly for potentiating photothermal therapy by depleting antioxidant defense systems