Cypate-loaded hollow mesoporous Prussian blue nanoparticle/hydrogel system for efficient photodynamic therapy/photothermal therapy dual-modal antibacterial therapy

Infectious diseases caused by pathogenic microorganisms are a significant burden on public health and the economic stability of societies all over the world. The appearance of drug-resistant bacteria has severely blocked the effectiveness of conventional antibiotics. Therefore, developing novel antibiotic-free strategies to combat bacteria holds huge potential for maximizing validity and minimizing the risk of enhancing bacterial resistance. Herein, a cypate-loaded hollow mesoporous Prussian blue nanoparticles (Cy-HMPBs) was built to achieve the PDT/PTT synergistic antimicrobial therapy. The carbomer hydrogel (CH) was combined with the Cy-HMPBs to form a nanoparticle/hydrogel therapeutic system (Cy-HMPBs/CH) to reach the goal of local delivery of antimicrobial cargo. The low concentration of Cy-HMPBs/CH receives over 99% of antimicrobial ability against Escherichia coli and Staphylococcus aureus upon near-infrared (NIR) irradiation. More importantly, Cy-HMPBs/CH has favorable biocompatibility and can play therapeutic effects only after laser irradiation, indicating the on-demand therapy at the targeted region to avert side effects on healthy tissue. This study provides ideas for the design of an antibiotic-free antimicrobial strategy against infectious diseases.

Pd(II)-Imprinted Chitosan Adsorbent for Selective Adsorption of Pd(II): Optimizing the Imprinting Process through Box-Behnken Experimental Design

The ion/molecular imprinting technique is an efficient method for developing materials with high adsorption selectivity. However, it is still difficult to obtain an imprinted adsorbent with desirably high selectivity when the preparation processes are not well designed and optimized. In this present work, a chitosan-based ion-imprinted adsorbent was optimally prepared through Box-Behnken experimental design to achieve desirably high selectivity for Pd anions (PdCl₄ ^2-) from aqueous solutions with high acidity. The dosage of epichlorohydrin (ECH) used in the first and second steps of cross-linking as well as the pH of the imprinting reaction medium is likely one of the key factors affecting the selectivity of the synthesized ion-imprinted chitosan adsorbent, which were selected as factors in a three-level factorial Box-Behnken design. As a result, the effects of these three factors on Pd(II) selectivity were able to be described by using a second-order polynomial model with a high regression coefficient (R ²; 0.996). The obtained optimal conditions via the response surface methodology were 0.10% (v/v) of first cross-linking ECH, an imprinting pH of 1.0, and 1.00% of second cross-linking ECH. Competitive adsorption was performed to investigate the selectivities of the ion-imprinted chitosan adsorbents prepared under the optimal conditions. The selectivity coefficient of Pd(II) versus Pt(IV) (β_Pd/Pt) of the Pd(II)-imprinted adsorbent was 115.83, much greater than that of the chitosan adsorbent without imprinting and various reported selective adsorbents. Therefore, the Box-Behnken design can be a useful method for optimizing the synthesis of ion-imprinted adsorbents with desirably high adsorptive selectivity for precious metals.

Photoinduced electron transfer dynamics of AuNPs and Au@PdNPs supported on graphene oxide probed by dark-field hyperspectral microscopy

The time scale for interfacial photoinduced electron transfer (PeT) in plasmonic nanoparticles is not well established and the details are still under debate. This has renewed the interest in studying the electron transfer effect from both experimental and theoretical points of view. We present a quantitative analysis of PeT in single spherical gold (Au) and gold@palladium core@shell (Au@Pd) nanoparticles supported on reduced graphene oxide (RGO) using dark-field hyperspectral microscopy (DFHM) and electrochemical impedance spectroscopy (EIS). By studying the plasmon bandwidth in the scattering spectra of single particles and by correlating it to the plasmon damping processes we showed that PeT occurs from the AuNPs to RGO in a 10 fs time scale with a quantum efficiency of 35%. The introduction of a Pd shell on the AuNPs decreases the PeT time, with transfer occurring in as little as 1.7 fs with quantum yield higher than 74%. Furthermore, EIS showed a smaller resistance for PeT on RGO/Au@PdNPs under green light illumination. Our results can improve the understanding of the chemical interface damping process due to PeT in plasmonic nanomaterials and can enable the design of more efficient plasmon enhanced photocatalysts.

Functionalized Carbon Nanostructures Versus Drug Resistance: Promising Scenarios in Cancer Treatment

Carbon nanostructures (CN) are emerging valuable materials for the assembly of highly engineered multifunctional nanovehicles for cancer therapy, in particular for counteracting the insurgence of multi-drug resistance (MDR). In this regard, carbon nanotubes (CNT), graphene oxide (GO), and fullerenes (F) have been proposed as promising materials due to their superior physical, chemical, and biological features. The possibility to easily modify their surface, conferring tailored properties, allows different CN derivatives to be synthesized. Although many studies have explored this topic, a comprehensive review evaluating the beneficial use of functionalized CNT vs G or F is still missing. Within this paper, the most relevant examples of CN-based nanosystems proposed for MDR reversal are reviewed, taking into consideration the functionalization routes, as well as the biological mechanisms involved and the possible toxicity concerns. The main aim is to understand which functional CN represents the most promising strategy to be further investigated for overcoming MDR in cancer.

Noble Metals Based Bimetallic and Trimetallic Nanoparticles: Controlled Synthesis, Antimicrobial and Anticancer Applications

Noble bimetallic and trimetallic nanoparticles (NBT-NPs) have superior biomedical applications as compared to their monometallic counterparts. The performance of these nanomaterials depends on their composition, shape and size. Hence, the controlled-synthesis of these nanomaterials is a hot area of research. Till date, no review article in the literature accounts regarding the controlled-synthesis and biomedical applications related to morphology, optimum composition, biocompatibility and versatile chemistry of NBT-NPs. Taking this into contemplation, an effort was made to provide a clear insight into the morphology-controlled synthesis and size/shape-dependent anticancer and bactericidal applications of NBT-NPs. Chemical reduction method for the controlled-synthesis of NBT-NPs is reviewed critically. Furthermore, the potential role of various reaction parameters such as time, reducing agents, stabilizing/capping agents, nature/concentration of precursors, temperature and pH in the shape/size-controlled synthesis of these nanomaterials are discussed. In the second part of this article, anticancer and bactericidal applications of the NBT-NPs are reviewed and the influences of optimum composition, size, surface structure, versatile chemistry and synergism are studied. Finally, the current challenges in the controlled-synthesis and biomedical applications of these nanomaterials, and prospects to resolve related issues are discussed. HighlightsChemical reduction method for the synthesis of NBT-NPs is reviewed.The influences of parameters on the control synthesis of NBT-NPs are discussed.Antibacterial and anticancer applications and cytotoxicity of NBT-NPs are reviewed.Possible solutions for the key challenges are discussed.Outlooks about the synthesis and biomedical applications of NBT-NPs are discussed.

Ag and Au nanoparticles/reduced graphene oxide composite materials: Synthesis and application in diagnostics and therapeutics

The exceptional electrical, thermal, optical and mechanical properties have made two dimensional sp² hybridized graphene a material of choice in both academic as well as industrial research. In the last few years, researchers have devoted their efforts towards the development of graphene/polymer, graphene/metal nanoparticle and graphene/ceramic nanocomposites. These materials display excellent mechanical, electrical, thermal, catalytic, magnetic and optical properties which cannot be obtained separately from the individual components. Fascinating physical and chemical properties are displayed by noble metal nanomaterials and thus they represent model building blocks for modifying nanoscale structures for diverse applications extending from catalysis, optics to nanomedicine. Insertion of noble metal (Au, Ag) nanoparticles (NPs) into chemically derived graphene is thus of primary importance to open new avenues for both materials in various fields where the specific properties of each material act synergistically to provide hybrid materials with exceptional performances. This review attempts to summarize the different synthetic procedures for the preparation of Ag and Au NPs/reduced graphene oxide (rGO) composites. The synthesis processes of metal NPs/rGO composites are categorised into in-situ and ex-situ techniques. The in-situ approach consists of simultaneous reduction of metal salts and GO to obtain metal NPs/rGO nanocomposite materials, while in the ex-situ process, the metal NPs of desired size and shape are first synthesized and then transferred onto the GO or rGO matrix. The application of the Ag NPs and Au NPs/rGO composite materials in the area of biomedical (drug delivery and photothermal therapy) and biosensing are the focus of this review article.

Nanobiomaterials: from 0D to 3D for tumor therapy and tissue regeneration

Nanobiomaterials have attracted tremendous attention in the biomedical field. Especially in the past few years, a large number of low dimensional nanobiomaterials, including 0D nanostructures, 1D nanotubes and 2D nanosheets, were employed for tumor therapy due to their optically triggered tumor therapy effects and drug loading capacities. However, these low dimensional nanobiomaterials cannot support cell adhesion and possess poor tissue regeneration ability, thus they are not suitable for application in regenerative medicine. Three dimensional (3D) nanofiber scaffolds have attracted extensive attention in tissue regeneration, including bone, skin, nerve and cardiac tissues, due to their similar extracellular matrix structures. Additionally, many 3D scaffolds displayed bone and cartilage regeneration abilities. Therefore, to obtain materials with both tumor therapy and tissue regeneration abilities, it is meaningful and necessary to develop 3D nanobiomaterials with multifunctions. In this review, we systematically review the research progress of nanobiomaterials with varied dimensional structures including 0D, 1D, 2D and 3D, as well as evolutional functions from single tumor therapy to simultaneous tumor therapy and tissue regeneration. This review may pave the way for developing an interdisciplinary research of nanobiomaterials in combination of tumor therapy and regenerative medicine.

Cavitation Induced by Janus-Like Mesoporous Silicon Nanoparticles Enhances Ultrasound Hyperthermia

The presence of nanoparticles lowers the levels of ultrasound (US) intensity needed to achieve the therapeutic effect and improves the contrast between healthy and pathological tissues. Here, we evaluate the role of two main mechanisms that contribute to the US-induced heating of aqueous suspensions of biodegradable nanoparticles (NPs) of mesoporous silicon prepared by electrochemical etching of heavily boron-doped crystalline silicon wafers in a hydrofluoric acid solution. The first mechanism is associated with an increase of the attenuation of US in the presence of NPs due to additional scattering and viscous dissipation, which was numerically simulated and compared to the experimental data. The second mechanism is caused by acoustic cavitation leading to intense bubble collapse and energy release in the vicinity of NPs. This effect is found to be pronounced for as-called Janus NPs produced via a nano-stopper technique, which allow us to prepare mesoporous NPs with hydrophobic inner pore walls and hydrophilic external surface. Such Janus-like NPs trap air inside the pores when dispersed in water. The precise measurement of the heating dynamics in situ enabled us to detect the excessive heat production by Janus-like NPs over their completely hydrophilic counterparts. The excessive heat is attributed to the high intensity cavitation in the suspension of Janus-like NPs. The present work elicits the potential of specifically designed Janus-like mesoporous silicon NPs in the field of nanotheranostics based on ultrasound radiation.

Graphene- gold based nanocomposites applications in cancer diseases; Efficient detection and therapeutic tools

Early detection and efficient treatment of cancer disease remains a drastic challenge in 21st century. Throughout the bulk of funds, studies, and current therapeutics, cancer seems to aggressively advance with drug resistance strains and recurrence rates. Nevertheless, nanotechnologies have indeed given hope to be the next generation for oncology applications. According to US National cancer institute, it is anticipated to revolutionize the perspectives of cancer diagnosis and therapy. With such success, nano-hybrid strategy creates a marvelous preference. Herein, graphene-gold based composites are being increasingly studied in the field of oncology, for their outstanding performance as robust vehicle of therapeutic agents, built-in optical diagnostic features, and functionality as theranostic system. Additional modes of treatments are also applicable including photothermal, photodynamic, as well as combined therapy. This review aims to demonstrate the various cancer-related applications of graphene-gold based hybrids in terms of detection and therapy, highlighting the major attributes that led to designate such system as a promising ally in the war against cancer.

Functionalized graphene nanocomposites for enhancing photothermal therapy in tumor treatment

Graphene and its derivatives have unique physical and chemical properties that make them promising vehicles for photothermal therapy (PTT)-based cancer treatment. With intrinsic near-infrared (NIR) absorption properties, graphene-based nanomaterials can be used for PTT and other therapeutics, particularly in combination therapy, to provide successful thermal ablation of cancer cells. In the recent years, advances in graphene-based PTT have produced efficient and efficacious tumor inhibition via nanomaterial structural design and different functionalizations of graphene-derived nanocomposites. Graphene-based nanosystems exhibit multifunctional properties that are useful for PTT applications including enhancement of multimodalities, guided imaging, enhanced chemotherapy and low-power efficient PTT for optimum therapeutic efficiency. Therefore, in this review, we address critical issues and future aspects of PTT-based combination therapy.

Gold nanoparticles coated with a polydopamine layer and dextran brush surface for diagnosis and highly efficient photothermal therapy of tumors

The nanoparticles improved tumor CT imaging and cured tumors after injection of the nanoparticles followed by NIR laser irradiation.