Synthesis of molybdenum oxide nanoparticles by nanosecond laser ablation

Phothermal therapy (PTT) is one of the most promising techniques to treat cancer. Finding the ideal PTT agent nanomaterial has remained a challenge and has brought the interest of several researchers. In this work, we report the synthesis of molybdenum oxide (MoOx) nanoparticles (NPs), which exhibit absorption in the biological optical window ~840 nm, by using the laser ablation of solids in liquids (LASL) technique with nanosecond (ns) pulses. A Nd:YAG laser was used to synthesize the NPs in deionized (DI) water, free of surfactants or additives, which were optically characterized by absorption spectroscopy and TEM-EDX microscopy. Semi spherical NPs with a suitable average size and shape for potential use as PTT agents were obtained by laser ablation and ablation + fragmentation. The calculated band gap is 3.1 eV, which corresponds to MoO3. Micro-Raman spectroscopy studies determined that these NPs are composed of amorphous molybdenum oxide hydrates (MoO3 · xH2O)

Electronic Tuning of Mixed Quinoidal‐Aromatic Conjugated Polyelectrolytes: Direct Ionic Substitution on Polymer Main‐Chains

The synthesis of conjugated polymers with ionic substituents directly bound to their main chain repeat units is a strategy for generating strongly electron-accepting conjugated polyelectrolytes, as demonstrated through the synthesis of a series of ionic azaquinodimethane (iAQM) compounds. The introduction of cationic substituents onto the quinoidal para-azaquinodimethane (AQM) core gives rise to a strongly electron-accepting building block, which can be employed in the synthesis of ionic small molecules and conjugated polyelectrolytes (CPEs). Electrochemical measurements alongside theoretical calculations indicate notably low-lying LUMO values for the iAQMs. The optical band gaps measured for these compounds are highly tunable based on structure, ranging from 2.30 eV in small molecules down to 1.22 eV in polymers. The iAQM small molecules and CPEs showcase the band gap reduction effects of combining the donor-acceptor strategy with the bond-length alternation reduction strategy. As a demonstration of their utility, the iAQM CPEs so generated were used as active agents in photothermal therapy

Composite iron oxide–Prussian blue nanoparticles for magnetically guided T1-weighted magnetic resonance imaging and photothermal therapy of tumors

Theranostic nanoparticles offer the potential for mixing and matching disparate diagnostic and therapeutic functionalities within a single nanoparticle for the personalized treatment of diseases. In this article, we present composite iron oxide-gadolinium-containing Prussian blue nanoparticles (Fe3O4@GdPB) as a novel theranostic agent for T1-weighted magnetic resonance imaging (MRI) and photothermal therapy (PTT) of tumors. These particles combine the well-described properties and safety profiles of the constituent Fe3O4 nanoparticles and gadolinium-containing Prussian blue nanoparticles. The Fe3O4@GdPB nanoparticles function both as effective MRI contrast agents and PTT agents as determined by characterizing studies performed in vitro and retain their properties in the presence of cells. Importantly, the Fe3O4@GdPB nanoparticles function as effective MRI contrast agents in vivo by increasing signal:noise ratios in T1-weighted scans of tumors and as effective PTT agents in vivo by decreasing tumor growth rates and increasing survival in an animal model of neuroblastoma. These findings demonstrate the potential of the Fe3O4@GdPB nanoparticles to function as effective theranostic agents

Local generation of hydrogen for enhanced photothermal therapy.

By delivering the concept of clean hydrogen energy and green catalysis to the biomedical field, engineering of hydrogen-generating nanomaterials for treatment of major diseases holds great promise. Leveraging virtue of versatile abilities of Pd hydride nanomaterials in high/stable hydrogen storage, self-catalytic hydrogenation, near-infrared (NIR) light absorption and photothermal conversion, here we utilize the cubic PdH0.2 nanocrystals for tumour-targeted and photoacoustic imaging (PAI)-guided hydrogenothermal therapy of cancer. The synthesized PdH0.2 nanocrystals have exhibited high intratumoural accumulation capability, clear NIR-controlled hydrogen release behaviours, NIR-enhanced self-catalysis bio-reductivity, high NIR-photothermal effect and PAI performance. With these unique properties of PdH0.2 nanocrystals, synergetic hydrogenothermal therapy with limited systematic toxicity has been achieved by tumour-targeted delivery and PAI-guided NIR-controlled release of bio-reductive hydrogen as well as generation of heat. This hydrogenothermal approach has presented a cancer-selective strategy for synergistic cancer treatment

Classification of Cancer Cell Surface Proteins by Gold-Based Hybrid Nanoparticles and Optical Spectroscopy

This thesis pioneers an innovative exploration at the confluence of nanotechnology, surface-enhanced Raman scattering (SERS), and machine learning for the advancement of cancer diagnostics. The synthesis of nanoparticles opens new frontiers in nanoparticle design, promising unprecedented stability and multiplexing capabilities. The journey begins with a profound review of relevant literature, unraveling the historical evolution of nanoparticles and their transformative impact on diverse scientific domains. Navigating through the intricate landscape of nanoscience, the thesis elucidates the theoretical underpinnings governing the optical properties of nanoparticles. These insights, coupled with meticulous experimental validations, guide the tailored design of nanostructures, ensuring optimal performance in cancer cell detection. The narrative unfolds against the backdrop of theoretical framework, intertwining experimental verifications and computational models. Venturing into the experimental and computational domain, this thesis showcases the potential applications of application of gold nanoparticles in the areas of cancer research and nanomedicine, from multiplex capabilities to optical engineering. The synergy of theoretical frameworks and experimental validation methodologies propels this research to the forefront of cancer nanomedicine. Acknowledging the limitations and charting a course for future exploration, this thesis transcends disciplinary boundaries, contributing in the experimental and theoretical realms

Light-Mediated Deep-Tissue Theranostics

This theme issue provides an overview on recent developments of light-mediated imaging and therapy approaches, with an emphasis on those that transcend the shallow tissue penetration dogma

A novel high yield process for gold sulfide nanoparticle synthesis via shifting equilibrium of self-assembly reaction.

Gold nanoparticles (AuNPs) have attracted enormous attention in the field of nanotechnology for applications such as, immunoassay, drug delivery, contrast enhancement and tumor therapy. The typical range of gold nanoparticles varies from 1– 150 nm; there are many different subtypes of AuNPs mainly based on size, shape, and optical properties including: gold nanospheres, nanorods, nanocages, and nanoshells. The main advantage of using gold nanoparticles is the large surface-to-volume ratio; this will allow the particles to be functionalized with drugs and/or targeting agents to create many novel applications. Many AuNPs have another advantage as well, they can be fabricated to either absorb or scatter light in the visible to near-infrared (nIR) region of the spectrum. Current research, using gold nanoparticles, mainly focuses on taking advantage of the nIR window. In biomedical research the nIR window is very important; nIR light has minimal interference with tissue and only affects samples which absorb nIR light, which enables minimally invasive imaging and treatment. Specifically, gold/gold sulfide nanoparticles (GGS) have been introduced for many applications compared to silica-gold nanoshells due to the smaller size of particles. This project is focused on a novel purification/high yield process of GGS nanoparticles using chloroauric acid (HAuCl4) and sodium thiosulfate (Na2S2O3), with desired nIR peak that can be used for therapeutic applications. By combining the traditional published methods for 1-step self-assembly of GGS nanoparticles and dialysis techniques simultaneously, a new method for production of gold / gold-sulfide nanoparticles has been established in this research project which we call DiaSynth. In this process the equilibrium of the reaction is shifted to favor the formation of nIR absorbing particles. This technique minimizes production of gold nanoparticles with 530 nm resonance (colloidal gold), resulting in populations of nanoparticles that require minimum further processing for use as a therapeutic agent. The colloidal gold is considered a contaminant, formed during the self-assembly process, which are traditionally removed via multi-step centrifugation. We define a ratio of the absorbance of peaks, RnIR/Au ; this is based on the peak absorbance in of the nIR region (700 – 900 nm) relative to the colloidal gold peak (~530 nm) as a relative measure of the quality of nIR particles. The current method for producing nIR GGS, based on a single step procedure, results in a poor ratio, RnIR/Au = 0.7 – 1.0. The DiaSynth method utilizes a shift in kinetics via removal of smaller ions and other products during the reduction of gold and sulfur. This method has allowed us to increase the yield of as made product to have an RnIR/Au = 1.7 – 2.0. In comparison, purification by centrifugation results in great loss of particles during each step to achieve similar ratios. At a ratio of 1.7 – 2.36, no centrifugation is needed to separate out colloidal gold, resulting in reduced production costs and higher quality product

Photothermal Conversion Applications of the Transition Metal (Cu, Mn, Co, Cr, and Fe) Oxides with Spinel Structure

The transition metal (Cu, Mn, Co, Cr, and Fe) oxides with spinel structure can be used as solar absorber materials due to their unique properties. Copper-based spinel ceramic pigments have been successfully prepared by sol-gel combustion method at low temperatures. Subsequently, spinel ceramic pigments have been employed to fabricate selective absorber paint coating by spraying-coating. The paint coating showed good spectral selectivity and thermal stability at low-to-mid temperature region. Spinel ceramic films have also been deposited on metal substrates by one dipping/annealing cycle. Spinel phase for single-layer ceramic film could be achieved at low annealing temperatures, and the single-layer ceramic film showed good spectral selectivity and benign thermal stability. Results presented here show that spinel compounds based on transition metal (Cu, Mn, Co, Cr, and Fe) oxides are promising materials for photothermal conversion applications