Therapeutic possibilities of plasmonically heated gold nanoparticles

Advanced Thermoactive Nanomaterials for Thermomedical Tissue Regeneration: Opportunities and Challenges

Nanomaterials usually possess remarkable properties, including excellent biocompatibility, unique physical and chemical characteristics, and bionic attributes, which make them highly promising for applications in tissue regeneration. Thermal therapy has emerged as a versatile approach for wound healing, nerve repair, bone regeneration, tumor therapy, and antibacterial tissue regeneration. By combining nanomaterials with thermal therapy, multifunctional nanomaterials with thermogenic effects and tissue regeneration capabilities can be engineered to achieve enhanced therapeutic outcomes. This study provides a comprehensive review of the effects of thermal stimulation on cellular and tissue regeneration. Furthermore, it highlights the applications of photothermal, magnetothermal, and electrothermal nanomaterials, and thermally responsive drug delivery systems in tissue engineering. In Addition, the bioactivities and biocompatibilities of several representative thermal nanomaterials are discussed. Finally, the challenges facing thermal nanomaterials are outlined, and future prospects in the field are presented with the aim of offering new opportunities and avenues for the utilization of thermal nanomaterials in tissue regeneration.

Synergistic Effect in Hybrid Plasmonic Conjugates for Photothermal Applications

Photothermal conversion efficiency (η) plays a crucial role in selecting suitable gold nanoparticles for photothermal therapeutic applications. The photothermal efficiency depends on the material used for the nanoparticles as well as their various parameters, such as size and shape. By maximizing the light-to-heat conversion efficiency (η), one can reduce the concentration of nanoparticle drugs for photothermal cancer treatment and apply lower laser power to irradiate the tumor. In our study, we explored a new hybrid plasmonic conjugate for theranostic (therapy + diagnostic) applications. We conjugated PEG-functionalized 20 nm gold nanospheres with cyanine IR dyes via a PEG linker. The resulting conjugates exhibited significantly enhanced photothermal properties compared with bare nanoparticles. We experimentally showed that a proposed new hybrid plasmonic conjugate can achieve almost four times larger conversion efficiency (47.7%) than 20 nm gold nanospheres (12%). The enhanced photothermal properties of these gold conjugates can provide the required temperature for the photothermal treatment of cancer cells with lower concentrations of gold nanoparticles injected in the body as well as with lower applied incident laser power density. Moreover, the improved photothermal properties of the conjugates can be explained by a synergistic effect that has not been observed in the past. This effect results from the coupling between the metal nanosphere and the organic dye.

Magnetic Hyperthermia in Glioblastoma Multiforme Treatment

Glioblastoma multiforme (GBM) represents one of the most critical oncological diseases in neurological practice, being considered highly aggressive with a dismal prognosis. At a worldwide level, new therapeutic methods are continuously being researched. Magnetic hyperthermia (MHT) has been investigated for more than 30 years as a solution used as a single therapy or combined with others for glioma tumor assessment in preclinical and clinical studies. It is based on magnetic nanoparticles (MNPs) that are injected into the tumor, and, under the effect of an external alternating magnetic field, they produce heat with temperatures higher than 42 °C, which determines cancer cell death. It is well known that iron oxide nanoparticles have received FDA approval for anemia treatment and to be used as contrast substances in the medical imagining domain. Today, energetic, efficient MNPs are developed that are especially dedicated to MHT treatments. In this review, the subject's importance will be emphasized by specifying the number of patients with cancer worldwide, presenting the main features of GBM, and detailing the physical theory accompanying the MHT treatment. Then, synthesis routes for thermally efficient MNP manufacturing, strategies adopted in practice for increasing MHT heat performance, and significant in vitro and in vivo studies are presented. This review paper also includes combined cancer therapies, the main reasons for using these approaches with MHT, and important clinical studies on human subjects found in the literature. This review ends by describing the most critical challenges associated with MHT and future perspectives. It is concluded that MHT can be successfully and regularly applied as a treatment for GBM if specific improvements are made.

Gold nanoparticles coated with collagen-I and their wound healing activity in human skin fibroblast cells

The slow wound healing process has become a major health problem. Gold nanoparticles (AuNPs) have been used in various biomedical applications because of their unique properties. Type I collagen (Collagen-I) is a protein and be the most abundant type of collagen. This type of collagen can help the surrounding structure to maintain its rigidity. In this study, we stabilized the surface of AuNPs using Collagen-I (Collagen-I@AuNPs) and investigated the effect of Collagen-I@AuNPs on wound healing. The evaluation of inflammatory cytokine secretion, which were interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α), was performed. We found that Collagen-I@AuNPs reduced the levels of IL-6 and TNF-α in scratched human skin fibroblast (HSF) cells. Furthermore, Collagen-I@AuNPs induced the expression of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF), which are key growth factors involved in wound healing. This results in enhanced wound closure. In addition, Collagen-I@AuNPs were not toxic to HSF cells and facilitated the cellular uptake of particles inside HSF cells. Therefore, Collagen-I@AuNPs is a promising candidate for wound healing enhancement.

Inorganic nanoparticles for photothermal treatment of cancer

In recent years, inorganic nanoparticles (NPs) have attracted increasing attention as potential theranostic agents in the field of oncology. Photothermal therapy (PTT) is a minimally invasive technique that uses nanoparticles to produce heat from light to kill cancer cells. PTT requires two essential elements: a photothermal agent (PTA) and near-infrared (NIR) radiation. The role of PTAs is to absorb NIR, which subsequently triggers hyperthermia within cancer cells. By raising the temperature in the tumor microenvironment (TME), PTT causes damage to the cancer cells. Nanoparticles (NPs) are instrumental in PTT given that they facilitate the passive and active targeting of the PTA to the TME, making them crucial for the effectiveness of the treatment. In addition, specific targeting can be achieved through their enhanced permeation and retention effect. Thus, owing to their significant advantages, such as altering the morphology and surface characteristics of nanocarriers comprised of PTA, NPs have been exploited to facilitate tumor regression significantly. This review highlights the properties of PTAs, the mechanism of PTT, and the results obtained from the improved curative efficacy of PTT by utilizing NPs platforms.

Electrospun membranes chelated by metal magnesium ions enhance pro-angiogenic activity and promote diabetic wound healing

Diabetic wounds, resulting from skin atrophy due to localized ischemia and hypoxia in diabetic patients, lead to chronic pathological inflammation and delayed healing. Using electrospinning technology, we developed magnesium ion-chelated nanofiber membranes to explore their efficacy in antibacterial, anti-inflammatory, and angiogenic applications for wound healing. These membranes are flexible and elastic, resembling native skin tissue, and possess good hydrophilicity for comfortable wound bed contact. The mechanical properties of nanofiber membranes are enhanced by the chelation of magnesium ions (Mg2+), which also facilitates a long-term slow release of Mg2+. The cytocompatibility of the nanofibrous membranes is influenced by their Mg2+ content: lower levels encourage the proliferation of fibroblasts, endothelial cells, and macrophages, while higher levels are inhibitory. In a diabetic rat model, magnesium ion-chelated nanofibrous membranes effectively reduced early wound inflammation and notably accelerated wound healing. This study highlights the potential of magnesium ion-chelated nanofiber membranes in treating diabetic wounds.

Investigating the fate and toxicity of green synthesized gold nanoparticles in albino mice

OBJECTIVE

This study aims to investigate the acute and chronic adverse effects of ∼50 nm (nanometer) gold nanoparticles (AuNPs) synthesized using Ziziphus zizyphus leaf extract in mice.

SIGNIFICANCE

AuNPs have shown promise for medical applications, but their safety and biocompatibility need to be addressed. Understanding the potential adverse effects of AuNPs is crucial to ensure their safe use in medical applications.

METHODS

The ∼50 nm AuNPs were synthesized using Ziziphus zizyphus leaf extract and characterized using scanning electron microscopy, dynamic light scattering, and zeta potential analysis. Mice were subjected to a single intraperitoneal injection of AuNPs at a dose of 1 g/mg (grams per milligram) or a daily dose of 1 mg/kg for 28 days. Various parameters, including gold bioaccumulation, survival, behavior, body weight, and blood glucose levels, were measured. Histopathological changes and organ indices were assessed.

RESULTS

Gold levels in the blood and heart did not significantly increase with daily administration of AuNPs. However, there were proportional increases in gold content observed in the liver, spleen, and kidney, indicating effective tissue uptake. Histopathological alterations were predominantly observed in the kidney, suggesting potential tissue injury.

CONCLUSIONS

The findings of this study indicate that ∼50 nm AuNPs synthesized using Z. zizyphus leaf extract can induce adverse effects, particularly in the kidney, in mice. These results highlight the importance of addressing safety concerns when using AuNPs in medical applications. Further investigations that encompass a comprehensive set of toxicological parameters are necessary to confirm the long-term adverse effects of AuNP exposure.

Hyaluronic Acid Modified Metal Nanoparticles and Their Derived Substituents for Cancer Therapy: A Review

The use of metal nanoparticles (M-NPs) in cancer therapy has gained significant consideration owing to their exceptional physical and chemical features. However, due to the limitations, such as specificity and toxicity towards healthy cells, their application in clinical translations has been restricted. Hyaluronic acid (HA), a biocompatible and biodegradable polysaccharide, has been extensively used as a targeting moiety, due to its ability to selectively bind to the CD44 receptors overexpressed on cancer cells. The HA-modified M-NPs have demonstrated promising results in improving specificity and efficacy in cancer therapy. This review discusses the significance of nanotechnology, the state of cancers, and the functions of HA-modified M-NPs, and other substituents in cancer therapy applications. Additionally, the role of various types of selected noble and non-noble M-NPs used in cancer therapy are described, along with the mechanisms involved in cancer targeting. Additionally, the purpose of HA, its sources and production processes, as well as its chemical and biological properties are described. In-depth explanations are provided about the contemporary applications of HA-modified noble and non-noble M-NPs and other substituents in cancer therapy. Furthermore, potential obstacles in optimizing HA-modified M-NPs, in terms of clinical translations, are discussed, followed by a conclusion and future prospects.

Association of nanoparticles and Nrf2 with various oxidative stress-mediated diseases

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regultes the cellular antioxidant defense system at the posttranscriptional level. During oxidative stress, Nrf2 is released from its negative regulator Kelch-like ECH-associated protein 1 (Keap1) and binds to antioxidant response element (ARE) to transcribe antioxidative metabolizing/detoxifying genes. Various transcription factors like aryl hydrocarbon receptor (AhR) and nuclear factor kappa light chain enhancer of activated B cells (NF-kB) and epigenetic modification including DNA methylation and histone methylation might also regulate the expression of Nrf2. Despite its protective role, Keap1/Nrf2/ARE signaling is considered as a pharmacological target due to its involvement in various pathophysiological conditions such as diabetes, cardiovascular disease, cancer, neurodegenerative diseases, hepatotoxicity and kidney disorders. Recently, nanomaterials have received a lot of attention due to their unique physiochemical properties and are also used in various biological applications, for example, biosensors, drug delivery systems, cancer therapy, etc. In this review, we will be discussing the functions of nanoparticles and Nrf2 as a combined therapy or sensitizing agent and their significance in various diseases such as diabetes, cancer and oxidative stress-mediated diseases.

Functionalized Carbon Nanoparticles as Theranostic Agents and Their Future Clinical Utility in Oncology

Over the years, research of nanoparticle applications in pre-clinical and clinical applications has greatly advanced our therapeutic and imaging approaches to many diseases, most notably neoplastic disorders. In particular, the innate properties of inorganic nanomaterials, such as gold and iron oxide, as well as carbon-based nanoparticles, have provided the greatest opportunities in cancer theranostics. Carbon nanoparticles can be used as carriers of biological agents to enhance the therapeutic index at a tumor site. Alternatively, they can also be combined with external stimuli, such as light, to induce irreversible physical damaging effects on cells. In this review, the recent advances in carbon nanoparticles and their use in cancer theranostics will be discussed. In addition, the set of evaluations that will be required during their transition from laboratory investigations toward clinical trials will be addressed.

Decorated Au NPs on lignin coated magnetic nanoparticles: Investigation of its catalytic application in the reduction of aromatic nitro compounds and its performance against human lung cancer

In the recent years, bio-functionalized noble metal doped advanced magnetics nanocomposite materials has been materialized as potential featured catalysts in diverse applications. In this connection, we report herein a novel biogenic lignin driven Au nanoparticle supported Fe₃O₄ composite material. The procedure is free from any harsh reducing or stabilizing agent. Morphology and structural features were assessed following different physicochemical methodologies like FT-IR, FE-SEM, TEM, EDS, XRD, VSM and ICP-OES techniques. Thereafter, the [Fe₃O₄/Lignin/Au] material was successfully employed in the efficient reduction of different nitroarenes in aqueous medium. The process was monitored over UV-Vis spectroscopic study. Excellent yields were achieved with a range of diverse functionalized nitroarenes within 10-45 min of reaction. The nanocatalyst was recycled 10 times without any significant loss of catalytic activity. Distinctiveness of the material's activity was validated by comparing the results in the reduction of 4-nitrophenol. Furthermore, the prepared [Fe₃O₄/Lignin/Au] nanocomposite system exhibited outstanding antioxidant and anticancer effects against five lung cancer cell lines, such as, BICR 3, BICR 78, CALU 1, ChaGo-K-1, and A549. Cytotoxicity assay was determined in terms of % cell viability following MTT protocol. The corresponding IC₅₀ values were obtained as 47, 31, 19, 25, and 31 μg/mL respectively.

Metal nanoparticles as a promising technology in targeted cancer treatment

Traditional anticancer treatments have several limitations, but cancer is still one of the deadliest diseases. As a result, new anticancer drugs are required for the treatment of cancer. The use of metal nanoparticles (NPs) as alternative chemotherapeutic drugs is on the rise in cancer research. Metal NPs have the potential for use in a wide range of applications. Natural or surface-induced anticancer effects can be found in metals. The focus of this review is on the therapeutic potential of metal-based NPs. The potential of various types of metal NPs for tumor targeting will be discussed for cancer treatment. The in vivo application of metal NPs for solid tumors will be reviewed. Risk factors involved in the clinical application of metal NPs will also be summarized.

On the toxicity of gold nanoparticles: Histological, histochemical and ultrastructural alterations

Gold nanoparticles (Au NPs) are used in diagnostic and therapeutic applications together with a variety of industrial purposes and in many biomedical sectors with potential risks to human health. The present study aimed to the histological, histochemical, and ultrastructural alterations induced by Au NPS in vital organs. Healthy male Wistar Albino rats (Rattus norvegicus) were subjected to 20 injections of 10-nm Au NPs at a daily dose of 2 mg/kg. Liver, kidney, heart, and lung biopsies from control and Au NPs-treated rats under study were subjected to histological and histochemical examinations. In comparison with the control rats, the renal tissue of Au NPs-treated rats demonstrated glomerular congestion, interstitial inflammatory cell infiltration, renal tubular hydropic degeneration, cloudy swelling, necrosis, and hyaline cast precipitation. In addition, Au NPs induced the following hepatic alterations: hepatocyte cytolysis, cytoplasmic vacuolation, hydropic degeneration, and nuclear alterations together with sinusoidal dilatation. Moreover, the hearts of the treated rats demonstrated myocarditis, cardiac congestion, hyalinosis, cardiomyocyte hydropic degeneration, myofiber disarray and cardiac congestion. The lungs of Au NPs-treated rats also exhibited the following pulmonary alterations: alectasis, emphysema, inflammatory cell inflammation, thickened alveolar walls, pulmonary interstitial edema, congestion, hypersensitivity, fibrocyte proliferation, and honeycombing. In conclusion, exposure to Au NPs induced histological, histochemical and ultrastructural alterations in the vital organs that may alter the function of these organs. Additional efforts are needed for better understanding the potential risks of Au NPs to human health.

Biosafe Bi2O2Se ultrathin nanosheet for water disinfection via solar-induced photothermal synergistic effect

Solar-induced sterilization via photothermal synergy has attracted enormous attention due to its zero-energy consumption and the elimination of hazardous chemical disinfectant. Herein, we successfully synthesized a super biosafety Bi₂O₂Se with crossed nanosheet structure (Bi₂O₂Se-CN) for the sterilization of Escherichia coli (E. coli) via solar-induced photothermal synergistic effect. In comparison to bulk Bi₂O₂Se, the lower light reflection and more efficient photogenerated charge carrier separation under visible-infrared light irradiation resulted in the excellent sterilization effect of Bi₂O₂Se-CN, with a sterilization efficiency of 99.9% under the synergistic effect of light and heat. The crossed ultrathin nanosheet structure and suitable band gap width of Bi₂O₂Se-CN are fundamental reasons for its enhanced light absorption and charge carrier separation efficiency. Mechanistic studies showed that Bi₂O₂Se-CN can completely inactivate bacteria via generating a large amount of reactive oxygen species (•O₂^-, •OH, and ¹O₂) to attack the cell membrane, which further resulted in the reduced activity of intracellular enzymes and the leakage of intracellular contents. The biosafety property of Bi₂O₂Se-CN was confirmed by in vivo toxicological evaluation on the mice model. This work provided new ideas for the design of more efficient, energy-saving, biocompatible and environmental friendly solar water purification projects.

Gold nanoparticles: current and upcoming biomedical applications in sensing, drug, and gene delivery

Gold nanoparticles (AuNPs) present unique physicochemical characteristics, low cytotoxicity, chemical stability, size/morphology tunability, surface functionalization capability, and optical properties which can be exploited for detection applications (colorimetry, surface-enhanced Raman scattering, and photoluminescence). The current challenge for AuNPs is incorporating these properties in developing more sensible and selective sensing methods and multifunctional platforms capable of controlled and precise drug or gene delivery. This review briefly highlights the recent progress of AuNPs in biomedicine as bio-sensors and targeted nano vehicles.

Bioactive Flavonoid used as a Stabilizing Agent of Mono and Bimetallic Nanomaterials for Multifunctional Activities

The multifunctional features of noble metal nanoparticles (MNPs) were exploited in various biomedical applications, which eventually demanded the development of a sustainable green synthesis approach. In the present study, Quercetin (Q) was employed as a promising green reductant for the generation of noble metal nanoparticles such as silver (Q-AgNPs), gold (Q-AuNPs), and bimetallic (Q-Ag-AuNPs) towards biomedical perspective. Initially, the NPs were successfully synthesized in a size-controlled manner via optimizing temperature, pH, metal ion concentration, and stoichiometric ratio of the reaction mix. The redox reaction and conversion of metal ions (Ag+ and Au3+) into their respective metal nano-forms were confirmed through their surface plasmonic resonance (SPR) in UV-visible spectroscopy. In addition, different instrumentation like FT-IR, XRD, HR-TEM, and XPS analyses were performed to confirm the size, shape, and chemical composition of fabricated NPs. The bactericidal effect of fabricated NPs was tested against Gram-positive and Gram-negative pathogens. Moreover, the cytotoxic potential was screened against breast (MCF-7) and colorectal (HCT-116) carcinoma cell lines. This work revealed that the flavonoid-functionalized noble metal NPs were associated with good antibacterial and anticancer potential against selected cancer cell lines.

Gold Nanorods-Based Photothermal Therapy: Interactions Between Biostructure, Nanomaterial, and Near-Infrared Irradiation

Gold nanorods (AuNRs) are ideal inorganic nanophotothermal agents with unique characteristics, including local surface plasmon resonance effects, easy scale preparation and functional modification, and good biocompatibility. This review summarizes several recent advances in AuNRs-based photothermal therapy (PTT) research. Functionalized AuNRs photothermal agents have optimized biocompatibility and targeting properties. The multifunctional AuNRs nanoplatform composite structure meets the requirements for synergistic effects of PTT, photoacoustic imaging, and other therapeutic methods. Photothermal therapy with AuNRs (AuNRs-PTT) is widely used to treat tumors and inflammatory diseases; its tumor-targeting, tumor metastasis inhibition, and photothermal tumor ablation abilities have remarkable curative effects. An in-depth study of AuNRs in living systems and the interactions between biological structure, nanomaterial, and near-infrared irradiation could lay the foundation for further clinical research and the broad application of AuNRs in PTT.

Antimicrobial Analysis of Biosynthesized Lectin-Conjugated Gold Nanoparticles

To enhance the bioactivity of molecules through nanoparticles is being tested which has potential use in sustained-release drug delivery systems and to enhance the therapeutic effectiveness of drugs. Our current investigation s is to conjugate lectin to that of a gold nanoparticle (GNP) surface without disturbing the bioactive properties and enhances the antibacterial activity of lectin. Au-lectin nanoparticles were checked for their hemagglutination activity, characterized by transmission electron microscopy (TEM) and UV-visible spectrophotometer. The antibacterial effect of nanoparticle lectin, Au salt nanoparticle, and conjugated Au-lectin was estimated by Kirby-Bauer disc method; MICs were determined by microbroth dilution and compared with ciprofloxacin. These tests were done using known species of bacterial strain of multidrug resistant. The hemagglutination activity of lectin was improved to fourfold after purification. Lectin and Au nanoparticles combined had a significant effect on the inhibition of bacterial growth. No significant differences were observed in the inhibition zone diameters from killed bacteria and its supernatant towards any of the tested organisms. Lectin-conjugated gold particles showed good efficacy as antimicrobial agents and the nanoparticle-killed bacteria to work against the viable population of the same bacterium and/or other bacterial species too.

Liposome-Tethered Gold Nanoparticles Triggered by Pulsed NIR Light for Rapid Liposome Contents Release and Endosome Escape

Remote triggering of contents release with micron spatial and sub-second temporal resolution has been a long-time goal of medical and technical applications of liposomes. Liposomes can sequester a variety of bioactive water-soluble ions, ligands and enzymes, and oligonucleotides. The bilayer that separates the liposome interior from the exterior solution provides a physical barrier to contents release and degradation. Tethering plasmon-resonant, hollow gold nanoshells to the liposomes, or growing gold nanoparticles directly on the liposome exterior, allows liposome contents to be released by nanosecond or shorter pulses of near-infrared light (NIR). Gold nanoshells or nanoparticles strongly adsorb NIR light; cells, tissues, and physiological media are transparent to NIR, allowing penetration depths of millimeters to centimeters. Nano to picosecond pulses of NIR light rapidly heat the gold nanoshells, inducing the formation of vapor nanobubbles, similar to cavitation bubbles. The collapse of the nanobubbles generates mechanical forces that rupture bilayer membranes to rapidly release liposome contents at the preferred location and time. Here, we review the syntheses, characterization, and applications of liposomes coupled to plasmon-resonant gold nanostructures for delivering a variety of biologically important contents in vitro and in vivo with sub-micron spatial control and sub-second temporal control.

Multifunctional plasmonic gold nanostars for cancer diagnostic and therapeutic applications

Gold nanostar (AuNSt) has gained great attention in bioimaging and cancer therapy due to their tunable surface plasmon resonance across the visible-near infrared range. Photothermal treatment and imaging capabilities including fluorescence lifetime imaging at two-photon excitation (TP-FLIM) and dark-field microscopic imaging are considered in this work. Two types of AuNSts having plasmon absorption peaks centred at 600 and 750 nm wavelength were synthesized and studied. Both NSts exhibited low cytotoxicity on A549 human lung carcinoma cells. A strong emission at two-photon excitation was observed for both NSts, well-distinguishable from lifetimes of bio-object autofluorescence. High efficiency in raising the temperature in the NSts environment with the irradiation of near infrared, AuNSts triggered photothermal effect. The decreased cell viability of A549 observed via MTT test and the cell membrane damaging was demonstrated with trypan blue staining. These results suggest AuNSts can be agents with tunable plasmonic properties for imaging and photothermal therapy.

Current Advances Toward the Encapsulation of Cas9

Genetic diseases present formidable hurdles in maintaining a good quality of life for those suffering from these ailments. Often, patients look to inadequate treatments to manage symptoms, which can result in harmful effects on the body. Through genetic engineering, scientists utilize the clustered regularly short palindromic repeat (CRISPR)-associated protein, known as Cas9, to treat the root of the problem. The Cas9 protein is often codelivered with guide RNAs or in ribonucleoprotein complexes (RNP) to ensure targeted delivery of the genetic tool as well as to limit off-target effects. This paper provides an overview of the current advances made toward the encapsulation and delivery of Cas9 to desired locations in the body through encapsulating nanoparticles. Several factors must be considered when employing the Cas9 system to allow gene editing to occur. Material selection is crucial to protect the payload of the delivery vector. Current literature indicates that lipid- and polymer-based nanoparticles show the most potential as delivery vessels for Cas9. Lipid nanoparticles greatly outpace polymer-based nanoparticles in the clinic, despite the benefits that polymers may introduce. When developing translatable systems, there are factors that have not yet been considered that are relevant to Cas9 delivery that are highlighted in this Viewpoint. The proper functioning of Cas9 is dependent on maintaining a proper internal environment; however, there are gaps in the literature regarding these optimal conditions. Interactions between charges of the Cas9 protein, codelivered molecules, and delivery vehicles could impact the effectiveness of the gene editing taking place. While the internal charges of nanoparticles and their effects on Cas9 are presently undetermined, nanoparticles currently offer the ideal delivery method for the Cas9 protein due to their adequate size, modifiable external charge, and ability to be modified. Overall, a cationic lipid-/polymer-based nanoparticle system was found to have the most prospects in Cas9 delivery thus far. By understanding the successes of other systems, translatable, polymer-based delivery vehicles may be developed.

MCP-1-Functionalized, Core-Shell Gold Nanorod@Iron-Based Metal-Organic Framework (MCP-1/GNR@MIL-100(Fe)) for Photothermal Therapy

The low vessel density and oxygen concentration in hypoxia are the main causes of reduced efficiency of anticancer therapeutics and can stimulate the tumor's relapse. Research showed that macrophages could cross the blood-vessel barriers and reach the hypoxic regions of tumors. Using macrophages in a drug delivery system has been a promising method for tumor targeting in recent years. In this work, we successfully modified monocyte chemoattractant protein-1 (MCP-1) and iron-based metal-organic framework (MIL-100(Fe)) on the photothermal agent, gold nanorods (GNRs) (i.e., MCP-1/GNR@MIL-100(Fe)), to increase cellular uptake and biocompatibility. The results of TEM, UV-vis, and FTIR all confirmed that we'd synthesized MCP-1/GNR@MIL-100(Fe) successfully, and the MCP-1/GNR@MIL-100(Fe) also showed good biocompatibility. A transwell migration assay illustrated that our material attracted macrophages, and the material uptake amount was increased by 1.5 times after MCP-1 functionalization. It also indicated that the macrophages have a tumor-targeting ability. In the in vivo experiment, we subcutaneously implanted U251 MG cells in nude mice as a xenograft model to demonstrate the photothermal activity of MCP-1/GNR@MIL-100(Fe). With successive NIR treatment, the tumor growth could be controlled, and the tumor volume still remained below 100 mm3 after laser treatment. MCP-1/GNR@MIL-100(Fe) combined with the laser treatment showed an excellent antitumor efficacy from the histology of tumor tissues, survival rates, and bioluminescence imaging.

Magnetic nanoparticles and clusters for magnetic hyperthermia: optimizing their heat performance and developing combinatorial therapies to tackle cancer

Magnetic hyperthermia (MHT) is a therapeutic modality for the treatment of solid tumors that has now accumulated more than 30 years of experience. In the ongoing MHT clinical trials for the treatment of brain and prostate tumors, iron oxide nanoparticles are employed as intra-tumoral MHT agents under a patient-safe 100 kHz alternating magnetic field (AMF) applicator. Although iron oxide nanoparticles are currently approved by FDA for imaging purposes and for the treatment of anemia, magnetic nanoparticles (MNPs) designed for the efficient treatment of MHT must respond to specific physical-chemical properties in terms of magneto-energy conversion, heat dose production, surface chemistry and aggregation state. Accordingly, in the past few decades, these requirements have boosted the development of a new generation of MNPs specifically aimed for MHT. In this review, we present an overview on MNPs and their assemblies produced via different synthetic routes, focusing on which MNP features have allowed unprecedented heating efficiency levels to be achieved in MHT and highlighting nanoplatforms that prevent magnetic heat loss in the intracellular environment. Moreover, we review the advances on MNP-based nanoplatforms that embrace the concept of multimodal therapy, which aims to combine MHT with chemotherapy, radiotherapy, immunotherapy, photodynamic or phototherapy. Next, for a better control of the therapeutic temperature at the tumor, we focus on the studies that have optimized MNPs to maintain gold-standard MHT performance and are also tackling MNP imaging with the aim to quantitatively assess the amount of nanoparticles accumulated at the tumor site and regulate the MHT field conditions. To conclude, future perspectives with guidance on how to advance MHT therapy will be provided.

Effect of shape and anthocyanin capping on antibacterial activity of CuI particles

The recent upsurge of antibiotic-resistant infections has posed to be a serious health concern worldwide. In the present paper, the effect of shape & capping agent on the antibacterial activity (on Skin and Urinary Tract Infection (UTI) causing bacteria) of copper iodide (CuI) particles was probed. CuI synthesized without a capping agent was leaf-like, and that with one was prismatic in shape. XRD of the synthesized CuI confirmed their high crystalline nature and purity. The average crystallite sizes of capped and uncapped CuI were calculated to be 91.10 nm and 89.01 nm respectively from X-Ray powder diffraction data. The average particle size of capped CuI was found to be 492.7 nm and that of uncapped CuI was found to be 2.96 μm using HR-SEM analysis. The crystals obtained were further characterized using EDAX, FTIR spectroscopy and UV-Visible spectroscopy. Antibacterial activity of prismatic CuI capped with the flower extract of Hibiscus rosa-sinensis showed better activity than that of uncapped CuI. AFM analysis was carried out to confirm the proposed mechanism for antibacterial activity through the morphological changes on the bacterial cell wall in the presence of capped CuI. Molecular docking studies were performed to reaffirm the enhanced antibacterial activity of prismatic CuI further. The present study demonstrates the superior antibacterial propensity of prismatic CuI, consequently making it a potent antibacterial agent.

Toxicity of gold nanoparticles (AuNPs): A review

Gold nanoparticles are a kind of nanomaterials that have received great interest in field of biomedicine due to their electrical, mechanical, thermal, chemical and optical properties. With these great potentials came the consequence of their interaction with biological tissues and molecules which presents the possibility of toxicity. This paper aims to consolidate and bring forward the studies performed that evaluate the toxicological aspect of AuNPs which were categorized into in vivo and in vitro studies. Both indicate to some extent oxidative damage to tissues and cell lines used in vivo and in vitro respectively with the liver, spleen and kidney most affected. The outcome of these review showed small controversy but however, the primary toxicity and its extent is collectively determined by the characteristics, preparations and physicochemical properties of the NPs. Some studies have shown that AuNPs are not toxic, though many other studies contradict this statement. In order to have a holistic inference, more studies are required that will focus on characterization of NPs and changes of physical properties before and after treatment with biological media. So also, they should incorporate controlled experiment which includes supernatant control Since most studies dwell on citrate or CTAB-capped AuNPs, there is the need to evaluate the toxicity and pharmacokinetics of functionalized AuNPs with their surface composition which in turn affects their toxicity. Functionalizing the NPs surface with more peculiar ligands would however help regulate and detoxify the uptake of these NPs.

Polymer coated gold nanoshells for combinational photochemotherapy of pancreatic cancer with gemcitabine

Pancreatic cancer is one of the most lethal malignancies with limited therapeutic options and dismal prognosis. Gemcitabine is the front-line drug against pancreatic cancer however with limited improvement of therapeutic outcomes. In this study we envisaged the integration of GEM with gold nanoshells which constitute an interesting class of nanomaterials with excellent photothermal conversion properties. Nanoshells were coated with thiol-capped poly(ethylene glycol) methacrylate polymers of different molecular weight via Au-S attachment. It was found that the molecular weight of the polymers affects the in vitro performance of the formulations; more importantly we demonstrate that the EC50 of nanoshell loaded GEM can be suppressed but fully restored and even improved upon laser irradiation. Our proposed nanoformulations outperformed the cytotoxicity of the parent drug and showed confined synergism under the tested in vitro conditions.

Gold nanoparticle-mediated generation of reactive oxygen species during plasmonic photothermal therapy: a comparative study for different particle sizes, shapes, and surface conjugations

Gold nanoparticle (AuNP)-mediated photothermal therapy represents an alternative to the effective ablation of cancer cells. However, the photothermal response of AuNPs must be tailored to improve the therapeutic efficacy of plasmonic photothermal therapy (PPT) and mitigate its side effects. This study presents an alternative to ease the tuning of photothermal efficiency and target selectivity. We use laser-treated spherical and anisotropic AuNPs of different sizes and biocompatible folic acid (FA)-conjugated AuNPs (FA-AuNPs) in the well-known human epithelial cervical cancer (HeLa) cell line. We show that large AuNPs produce a more significant photothermal heating effect than small ones. The thermal response of the spherical AuNPs of 9 nm was found to reach a maximum increase of 3.0 ± 1 °C, whereas with the spherical AuNPs of 14 nm, the temperature increased by over 4.4 ± 1 °C. The anisotropic AuNPs of 15 nm reached a maximum of 4.0 ± 1 °C, whereas the anisotropic AuNPs of 20 nm reached a significant increase of 5.3 ± 1 °C in the cell culture medium (MEM). Notably, the anisotropic AuNPs of 20 nm successfully demonstrate the potential for use as a photothermal agent by showing reduced viability down to 60% at a concentration of 100 μM. Besides, we reveal that high concentrations of reactive oxygen species (ROS) are formed within the irradiated cells. In combination with stress by photothermal heating, it is likely to result in significant cell death through acute necrosis by compromising the plasma membrane integrity. Cell death and ROS overproduction during PPT were characterized and quantified by transmission electron microscopy (TEM) and confocal fluorescence microscopy with different fluorescent markers. In addition, we show that FA-AuNPs induce cell death through apoptosis by internal damage, whereas diminish the ROS formation during PPT treatment. Our findings suggest the ability of plasmon-mediated ROS to sensitize cancer cells and make them vulnerable to photothermal damage, as well as the protective role of FA-AuNPs from excessive ROS formation, whereas reducing the risk of undesired side effects due to the necrotic death pathway. It allows an improvement in the efficacy of the AuNP-based photothermal therapy and a reduction in the number of exposures to high temperatures required to induce thermal stress.

Function of gold nanoparticles in oral cancer beyond drug delivery: Implications in cell apoptosis

OBJECTIVES

Gold nanoparticles (AuNPs) are used to deliver drugs and therapeutic small molecule inhibitors to cancer cells. Evidence shows that AuNPs coated with nuclear localization sequence can cross the nuclear membrane and induce cellular apoptosis. To determine the therapeutic role of AuNPs, we compared two nanoconstructs conjugated to doxorubicin (DOX) through pH-sensitive and pH-resistant linkers.

MATERIALS AND METHODS

We tested DOX nanoconjugates' cytotoxicity, cellular and nuclear uptake in oral squamous cell carcinoma cell line. Furthermore, we evaluated the therapeutic effect of pH-sensitive and pH-resistant DOX bioconjugates in hamster buccal pouch carcinoma model.

RESULTS

Our data indicate that pH-resistant and pH-sensitive DOX-nanoconjugates were equally localized in cancer cells, but the pH-resistant DOX nanoparticles were more localized in the nuclei inducing a 2-fold increase in the apoptotic effect compared with the pH-sensitive DOX nanoparticles. Our in vivo results show significantly higher tumor shrinkage and survival rates in animals treated with DOX pH-resistant AuNPs compared with pH-sensitive ones.

CONCLUSION

Our findings suggest that AuNPs enhance the cytotoxic effect against cancer cells in addition to acting as drug carriers. DOX pH-resistant AuNPs enhanced accumulation of AuNPs in cancer cells' nuclei inducing a significant cellular apoptosis which was confirmed using in vitro and in vivo experiments without deleterious effects on blood cell count.

Plasmonically Modulated Gold Nanostructures for Photothermal Ablation of Bacteria

With the wide utilization of antibiotics, antibiotic-resistant bacteria have been often developed more frequently to cause potential global catastrophic consequences. Emerging photothermal ablation has been attracting extensive research interest for quick/effective eradication of pathogenic bacteria from contaminated surroundings and infected body. In this field, anisotropic gold nanostructures with tunable size/morphologies have been demonstrated to exhibit their outstanding photothermal performance through strong plasmonic absorption of near-infrared (NIR) light, efficient light to heat conversion, and easy surface modification for targeting bacteria. To this end, this review first introduces thermal treatment of infectious diseases followed by photothermal therapy via heat generation on NIR-absorbing gold nanostructures. Then, the usual synthesis and spectral features of diversified gold nanostructures and composites are systematically overviewed with the emphasis on the importance of size, shape, and composition to achieve strong plasmonic absorption in NIR region. Further, the innovated photothermal applications of gold nanostructures are comprehensively demonstrated to combat against bacterial infections, and some constructive suggestions are also discussed to improve photothermal technologies for practical applications.

Potential Applications of Nanomaterials and Technology for Diabetic Wound Healing

Diabetic wound shows delayed and incomplete healing processes, which in turn exposes patients to an environment with a high risk of infection. This article has summarized current developments of nanoparticles/hydrogels and nanotechnology used for promoting the wound healing process in either diabetic animal models or patients with diabetes mellitus. These nanoparticles/hydrogels promote diabetic wound healing by loading bioactive molecules (such as growth factors, genes, proteins/peptides, stem cells/exosomes, etc.) and non-bioactive substances (metal ions, oxygen, nitric oxide, etc.). Among them, smart hydrogels (a very promising method for loading many types of bioactive components) are currently favored by researchers. In addition, nanoparticles/hydrogels can be combined with some technology (including PTT, LBL self-assembly technique and 3D-printing technology) to treat diabetic wound repair. By reviewing the recent literatures, we also proposed new strategies for improving multifunctional treatment of diabetic wounds in the future.

High-purity foam-like micron-sized gold cage material with tunable plasmon properties

Herein, by growing mono dispersed gold nanoparticles (MNPAu) on the surface of polystyrene (PS)/nanogold (Au) core–shell composites (PS@Au), we successfully synthesized a micron-sized gold cage (2.6–10.7 μm), referred to as PS@Au@MNPAu for the first time. The new micron-gold cage materials exhibit broadband absorption range from near-ultraviolet to near-infrared, which is unlike the conventional nanogold core–shell structure. The uniform growth of MNPAu on the surface forms a new photonic crystal spectrum. The strong coupling of the spectra causes anomalous absorption in the ultraviolet-near infrared band (400–900 nm). Furthermore, by removing the PS core, a nanogold cavity structure referred to as Au@MNPAu was prepared. This structure demonstrated a high purity (> 97 wt%), low density (9–223 mg/cm³), and high specific surface area (854 m²/g). As the purification process progressed, the MNPAu coupling on the surface of the micro-gold cage strengthened, resulting in the formation of peaks around 370 nm, plasma resonant peaks around 495 nm, and structural bands of photonic crystal peaks around 850 nm. The micron-sized gold cage provides hybridized and tunable plasmonic systems. The theoretical simulations indicate that this plasmon anomalous absorption phenomena can be understood as the novel form of the topological structural transitions near the percolation threshold, which is consistent experimental measurements.

Role of gold nanoparticles in advanced biomedical applications

Gold nanoparticles (GNPs) have generated keen interest among researchers in recent years due to their excellent physicochemical properties. In general, GNPs are biocompatible, amenable to desired functionalization, non-corroding, and exhibit size and shape dependent optical and electronic properties. These excellent properties of GNPs exhibit their tremendous potential for use in diverse biomedical applications. Herein, we have evaluated the recent advancements of GNPs to highlight their exceptional potential in the biomedical field. Special focus has been given to emerging biomedical applications including bio-imaging, site specific drug/gene delivery, nano-sensing, diagnostics, photon induced therapeutics, and theranostics. We have also elaborated on the basics, presented a historical preview, and discussed the synthesis strategies, functionalization methods, stabilization techniques, and key properties of GNPs. Lastly, we have concluded this article with key findings and unaddressed challenges. Overall, this review is a complete package to understand the importance and achievements of GNPs in the biomedical field.

Real-time monitoring of heat transfer between gold nanoparticles and tethered bilayer lipid membranes

Plasmon resonance frequency irradiated gold nanoparticles (GNPs) have gained interest as a laser-targeted treatment for infections, tumors and for the controlled release of drugs in situ. Questions still remain, however, as to the efficiency of heat delivery within biological tissues and how this can be reliably determined. Here, we demonstrate how a nanomaterial-electrode interface that mimics cell membranes can detect the localized heat transfer characteristics arising from plasmon resonance frequency-matched laser excitation of GNPs. We demonstrate that the lipid bilayer membrane can be affected by conjugated GNP induced hyperthermia when irradiated with a laser power output as low as 135 nW/μm². This is four orders of magnitude lower power than previously reported. By restricting the lateral movement of the lipids in the bilayer membrane, it was shown that the change in membrane conductance as a result of the heat transfer was due to the creation of transient lipidic toroidal pores within the membrane. We further demonstrate that the heat transfer from the GNPs alters diffusion rates of monomers of the gramicidin-A peptide within the lipid leaflets. This work highlights how targeted low laser power GNP hyperthermia treatments, in vivo, could play a dual role of interfering with both cell membrane morphology and dynamics, along with membrane protein function.

Past, Present, and Future of Anticancer Nanomedicine

This review aims to summarize the methods that have been used till today, highlight methods that are currently being developed, and predict the future roadmap for anticancer therapy. In the beginning of this review, established approaches for anticancer therapy, such as conventional chemotherapy, hormonal therapy, monoclonal antibodies, and tyrosine kinase inhibitors are summarized. To counteract the side effects of conventional chemotherapy and to increase limited anticancer efficacy, nanodrug- and stem cell-based therapies have been introduced. However, current level of understanding and strategies of nanodrug and stem cell-based therapies have limitations that make them inadequate for clinical application. Subsequently, this manuscript reviews methods with fewer side effects compared to those of the methods mentioned above which are currently being investigated and are already being applied in the clinic. The newer strategies that are already being clinically applied include cancer immunotherapy, especially T cell-mediated therapy and immune checkpoint inhibitors, and strategies that are gaining attention include the manipulation of the tumor microenvironment or the activation of dendritic cells. Tumor-associated macrophage repolarization is another potential strategy for cancer immunotherapy, a method which activates macrophages to immunologically attack malignant cells. At the end of this review, we discuss combination therapies, which are the future of cancer treatment. Nanoparticle-based anticancer immunotherapies seem to be effective, in that they effectively use nanodrugs to elicit a greater immune response. The combination of these therapies with others, such as photothermal or tumor vaccine therapy, can result in a greater anticancer effect. Thus, the future of anticancer therapy aims to increase the effectiveness of therapy using various therapies in a synergistic combination rather than individually.

Engineering Mono-Chalcogen Nanomaterials for Omnipotent Anticancer Applications: Progress and Challenges

Belonging to the chalcogen group, the elements selenium (Se) and tellurium (Te) are located in Group VI-A of the periodic table. Zero-valent nanodimensioned Se (nano-Se) and Te (nano-Te) have displayed important biomedical applications in recent years. The past two decades have witnessed an explosion in novel cancer treatment strategies using nano-Se and nano-Te as aggressive weapons against tumors. Indeed, they are both inorganic nanomedicines that suppress tumor cell proliferation, diffusion, and metastasis. Abundant synthesis strategies for rational and precise surface decoration of nano-Se and nano-Te make them significant players in resisting cancers by means of powerful multi-modal treatment methods. This review focuses on the design and engineering of nano-Se- and nano-Te-based nanodelivery systems and their precise uses in cancer treatment. The corresponding anticancer molecular mechanisms of nano-Se and nano-Te are discussed in detail. Given their different photo-induced behaviors, the presence or absence of near infrared illumination is used as a defining characteristic when describing the anticancer applications of nano-Se and nano-Te. Finally, the challenges and future prospects of nano-Se and nano-Te are summarized and highlighted.

Investigating the effect of gold nanoparticles on hydatid cyst protoscolices under low-power green laser irradiation

Objectives

Various scolicidal agents are applied for the destruction of protoscolices in cysts media. Undesirable complications of the scolicidal agents limit the techniques to treat the cyst disease. Therefore, new non-toxic scolicidal agents are needed. Upon laser light irradiation, the photothermal gold nanoparticles (AuNPs) convert the absorbed laser light into heat through photothermal effect which kills the surrounding protoscolices by rising the temperature of the cysts media. In this study, we introduced biocompatible AuNPs as a non-toxic scolicidal agent to cure liver hydatid cysts.

Material and Methods

The protoscoleces were collected from the livers of naturally infected sheeps. In each experimental group, 1.5 mL suspensions of hydatid liquid containing protoscolices were added to test tubes. The test tubes were divided into five groups. Control, AuNPs only, Green laser only, High-dose AuNPs + laser and Low-dose AuNPs + laser groups. Two concentrations (0.4 and 0.8 mL) of AuNPs and three laser powers (30, 50, 150 mW) were applied for 30, 60 and 120 minutes to the groups. Then the ciysts liquid assessed under a light microscope and determined the viability of protoscoleces.

Results

Protoscolices in high-dose AuNPs group were destructed up to 89.30% deaths under 150 mW laser power for 120 minutes. However, negligible cell deaths were observed in cases where only AuNPs added or only laser irradiated groups. Increasing the dose of AuNPs or laser power or duration of aplication increased the protoscolosidal death rate.

Conclusion

In the study, we have successfully demonstrated that the AuNPs are an effective therapeutic and scolicidal agent to cure hydatid cyst disease under laser irradiation.

Hesperidin Loaded on Gold Nanoparticles as a Drug Delivery System for a Successful Biocompatible, Anti-Cancer, Anti-Inflammatory and Phagocytosis Inducer Model

Hesperidin is a flavonoid glycoside with proven therapeutic activities for various diseases, including cancer. However, its poor solubility and bioavailability render it only slightly absorbed, requiring a delivery system to reach its therapeutic target. Hesperidin loaded on gold nanoparticles (Hsp-AuNPs) was prepared by a chemical synthesis method. Various characterization techniques such as UV-VIS spectroscopy, FTIR, XRD, FESEM, TEM and EDX, Zeta potential analysis, particle size analysis, were used to confirm the synthesis of Hsp-AuNPs. The cytotoxic effect of Hsp-AuNPs on human breast cancer cell line (MDA-MB-231) was assessed using MTT and crystal violet assays. The results revealed significant decrease in proliferation and inhibition of growth of the treated cells when compared with human normal breast epithelial cell line (HBL-100). Determination of apoptosis by fluorescence microscope was also performed using acridine orange-propidium iodide dual staining assay. The in vivo study was designed to evaluate the toxicity of Hsp-AuNPs in mice. The levels of hepatic and kidney functionality markers were assessed. No significant statistical differences were found for the tested indicators. Histological images of liver, spleen, lung and kidney showed no apparent damages and histopathological abnormalities after treatment with Hsp-AuNPs. Hsp-AuNPs ameliorated the functional activity of macrophages against Ehrlich ascites tumor cells-bearing mice. The production of the pro-inflammatory cytokines was also assessed in bone marrow–derived macrophage cells treated with Hsp-AuNPs. The results obviously demonstrated that Hsp-AuNPs treatment significantly inhibited the secretion of IL-1β, IL-6 and TNF.

A new way to prepare gold nanoparticles by sputtering - Sterilization, stability and other properties

We have developed a novel simple method for effective preparing gold nanoparticles (AuNPs) intended for utilization in biomedicine. The method is based on gold sputtering into liquid poly(ethylene glycol) (PEG). The PEG was used as a basic biocompatible stabilizer of the AuNP colloid. In addition, two naturally occurring polysaccharides - Chitosan (Ch) and Methylcellulose (MC) - were separately diluted into the PEG base with the aims to enhance the yield of the sputtering without changing the sputtering parameters, and to further improve the stability and the biocompatibility of the colloid. The colloids were sterilized by steam, and their stability was measured before and after the sterilization process by dynamic light scattering and UV-Vis spectrophotometry. The results indicated a higher sputtering yield in the colloids containing the polysaccharides. The colloids were also characterized by atomic absorption spectroscopy (AAS) to reveal the composition of the prepared nanoparticles by transmission electron microscopy (TEM) to visualize the nanoparticles and to evaluate their size and clustering, and by rheometry to estimate the viscosity of the colloids. The zeta-potential of the AuNPs was also determined as an important parameter indicating the stability and the biocompatibility of the colloid. In addition, in vitro tests of antimicrobial activity and cytotoxicity were carried out to estimate the biological activity and the biocompatibility of the colloids. Antimicrobial tests were performed by a drip test on two bacterial strains - Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli. AuNP with chitosan proved to possess the highest antibacterial activity, especially towards the Gram-positive S. epidermidis. In vitro tests on eukaryotic cells, i.e. human osteoblastic cell line SAOS-2 and primary normal human dermal fibroblasts (NHDF), were performed after a 7-day cultivation to determine the effect and the toxic dose of the colloids on human cells. The studied colloid concentrations were in the range from 0.6 μg/ml to 6 μg/ml. Toxicity of the colloids started to reappear at a concentration of 4.5 μg/ml, especially with chitosan in the colloid, where the colloid with a concentration of 6 μg/ml proved to be the most toxic, especially towards the SAOS-2 cell line. However, the PEG and PEG-MC containing colloids proved to be relatively non-toxic, even at the highest concentration, but with a slowly decreasing tendency of the cell metabolic activity.

Maximizing absorption and scattering by spherical nanoparticles

The absorption and scattering resonances of metal nanostructures are often assumed to be defined by the same condition of localized surface plasmon resonance. Using an electrostatic approximation, we demonstrate that the absorption and scattering cross sections of spherical nanoparticles reach their maxima at different wavelengths, which in turn differ from that defined by the Fröhlich condition (FC). These deviations from the FC originate from and are proportional to the material absorption. Our results provide the design guidelines for maximizing absorption and scattering of spherical nanoparticles and are thus of special importance for applications where the efficiency of radiation absorption or scattering is crucial.

A “turn-on” fluorescent and colorimetric chemodosimeter for selective detection of Au3+ ions in solution and in live cells via Au3+-induced hydrolysis of a rhodamine-derived Schiff base

A chromogenic and “off–on” fluorogenic chemodosimeter (L) based on a naphthalene–rhodamine B derivative was designed, synthesized and characterized for the selective and sensitive detection of Au³⁺ ions in mixed acetonitrile aqueous media.

Magnetic and light-responsive nanogels based on chitosan functionalized with Au nanoparticles and poly(N-isopropylacrylamide) as a remotely triggered drug carrier

Synthesis of thermosensitive nanogels based on functionalized chitosan with Au nanoparticles (NPs) and poly(NIPAM) to release of drug molecules under light exposure.

Tailored porphyrin–gold nanoparticles for biomedical applications

In this review we present an updated survey of the main synthesis methods of gold nanoparticles (AuNPs) in order to obtain various tailored nanosystems for biomedical imaging. The synthesis approach significantly impacts on the AuNPs properties such as surface chemistry, biocompatibility and cytotoxicity. In recent years, nanomedicine emphasized the development of functionalized AuNPs for biomedical imaging. AuNPs are a good option for used as delivery photosensitizer agents for PDT of cancer. For example, the complex formed from AuNPs functionalized with PEGylate porphyrins presents several advantages in the medical field such as a better use in photodynamic therapy because of high triplet states and singlet oxygen quantum yield efficiency of porphyrin molecules.

Application of Nanotechnology in Targeting of Cancer Stem Cells: A Review

Cancer is increasingly apparent as a systems-level, network happening. The central tendency of malignant alteration can be described as a two-phase procedure, where an initial increase of network plasticity is followed by reducing plasticity at late stages of tumor improvement. Cancer stem cells (CSCs) are cancer cells that take characteristics associated with normal stem cells. Cancer therapy has been based on the concept that most of the cancer cells have a similar ability to separate metastasise and kill the host. In this review, we addressed the use of nanotechnology in the treatment of cancer stem cells.

Photothermal versus photodynamic treatment for the inactivation of the bacteria Escherichia coli and Bacillus cereus: An in vitro study

The widespread occurrence of microbial pathogens, including multidrug-resistant (MDR) bacteria, has ignited research efforts to discover alternative strategies to combat infections in patients. Recently, photodynamic therapy (PDT) and photothermal therapy (PTT) have been proposed for the inactivation of pathogens. Although PDT and PTT are very promising antipathogenic tools, further effort is needed to determine their real impact on pathogens apart from the effects of individual elements involved in the photodynamic/photothermal processes, i.e., light, photosensitizers (PSs), and nanoparticles. Accordingly, in the current study, toluidine blue O (TBO) and gold nanoparticles (GNP) were used as generators of reactive oxygen species (ROS) and hyperthermia in the presence of light, respectively. Escherichia coli (E. coli) and Bacillus cereus (B. cereus) bacteria were chosen as examples of gram-negative and gram-positive bacteria, respectively. Before the bactericidal activity of PDT was assessed, the aggregation of TBO and its effect on the growth of both strains of bacteria were studied. Additionally, E. coli and B. cereus were exposed to a range of doses of 633 nm helium-neon laser light to investigate its effect. In a separate set of experiments, the bactericidal activity of PTT was assessed after the effects of GNP and green light (530 nm) had been assessed. The results showed that PDT and PTT should be considered useful tools for bacterial eradication even when the light, PSs, and nanoparticles are each used at doses safe for bacterial growth. Moreover, different photodynamic responses were observed for E. coli and B. cereus, and light from a 633 nm laser and a 530 nm light-emitting diode (LED) showed disparate responses when applied alone to both bacteria.