Photochemical Synthesis of Sericin-Coated Gold Nanorods and Their Antibacterial Activity under Low-Level Near-Infrared Light.

Gold nanorods (GNRs) are unique nanoparticles with easily functionalized surfaces, multiple synthesis methods, photothermal conversion, and surface plasmon resonance effects. These properties make GNRs suitable for various biological applications. However, a rapid synthesis of GNRs using less toxic chemicals is needed. The photochemical method is a viable option that can synthesize GNRs quickly while using fewer chemicals. A photochemical method is reported for the synthesis of GNRs using Irgacure-2959 as a reducing agent. This method could be used to synthesize GNRs with a rod-like shape within 30 min. Additionally, GNRs were coated with sericin (GNRs-SC) to further reduce their toxicity in human dermal fibroblast adult cells. Low-level near-infrared (NIR) light was applied to enhance the photothermal therapy of both GNRs and GNRs-SC. The results showed that GNRs and GNRs-SC under low-level NIR light have enhanced antibacterial activity against Staphylococcus aureus and Escherichia coli, as well as antibiofilm activity against S. aureus. Furthermore, GNRs-SC showed good biocompatibility with antibacterial and antibiofilm activities. These results indicate that GNRs-SC are good candidates for various biological applications.

Bimetallic nanoparticles with sulfated galactan eliminate Vibrio parahaemolyticus in shrimp Penaeus vannamei.

Bimetallic (Au/Ag) nanoparticles (BNPs) have shown enhanced antibacterial activity compared to their monometallic counterparts. Sulfated galactans (SG) are a naturally occurring polymer commonly found in red seaweed Gracilaria fisheri. They are biocompatible and biodegradable and environmentally friendly. In this study, we utilized SG in combination with BNPs to develop composite materials that potentially enhance antibacterial activity against shrimp pathogens Vibrio parahaemolyticus and Vibrio harveyi, compared to BNPs or SG alone. BNPs were coated with sulfated galactan (SGBNPs) and characterized using UV-vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, zeta potential, and transmission electron microscopy (TEM). UV-vis spectroscopy analysis revealed that the surface plasmon peaks of BNPs and SGBNPs appeared at 530 nm and 532 nm, respectively. Zeta potential measurements showed that SGBNPs had a negative charge of -32.4 mV, while the BNPs solution had a positive charge of 38.7 mV. TEM images demonstrated the spherical morphology of both BNPs and SGBNPs with narrow size distributions (3-10 nm). Analysis of the FTIR spectra indicated that SG maintained its backbone structure in SGBNPs, but some functional groups were altered. Notably, SGBNPs showed superior antimicrobial and antibiofilm activities against V. parahaemolyticus and V. harveyi compared to SG and BNPs. Furthermore, treatment with SGBNPs significantly down-regulated the expression of virulence-related genes (toxR, cpsQ, and mfpA) for V. parahaemolyticus 3HP compared to the respective control, bacteria treated with BNPs or SG. Diets supplemented with SGBNPs, BNPs, or SG showed no detrimental impact on the growth of shrimp Penaeus vannamei. Shrimp fed with SGBNPs-supplemented feed showed significantly higher survival rates than those fed with BNPs-supplemented feed when infected with 3HP after being on the supplemented feed for seven days and a subsequent number of fifteen days. These findings collectively demonstrate the benefit of using SG capped Au-Ag BNPs as an antibacterial agent for the prevention and control of Vibrio sp. Infection in shrimp while reducing the risk of environmental contamination.

Cytotoxic and inflammatory responses of TiO2 nanoparticles on human peripheral blood mononuclear cells.

Titanium dioxide nanoparticles (TiO2 -NPs) have been widely used in many applications. Owing to their nanoscale size, interactions between cells and NPs have been expansively investigated. With the health concerns raised regarding the adverse effects of these interactions, closer examination of whether TiO2 -NPs can induce toxicity towards human cells is greatly needed. Therefore, in this study, we investigated the cytotoxicity of TiO2 -NPs towards human blood cells (peripheral blood mononuclear cells [PBMCs]) in serum-free medium, for which there is little information regarding the cytotoxic effects of TiO2 -NPs. Our results provide evidence that PBMCs treated with TiO2 -NPs (at concentrations ≥25 µg ml(-1) ) for 24 h significantly reduced cell viability and significantly increased production of toxic mediators such as reactive oxygen species and inflammatory response cytokines such as interleukin-6 and tumor necrosis factor-α (P < 0.05). Cell apoptosis induction also occurred at these concentrations. Significant expressions of cyclooxygenase-2 and interleukin-1ß were also observed in PBMCs treated with TiO2 -NPs at concentrations ≥125 µg ml(-1) . Our data presented here clearly indicate that the concentration of TiO2 -NPs (at size ~26.4 ± 1.2 nm) applied to human blood cells has a strong impact on cytotoxic induction. Copyright © 2016 John Wiley & Sons, Ltd.

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.

Rapid alignment-free bacteria identification via optical scattering with LEDs and YOLOv8.

Rapid and accurate bacterial identification is essential for timely treatment of infections like sepsis. While traditional methods are reliable, they lack speed, and advanced molecular techniques often suffer from cost and complexity. The bacterial detection technology based on optical scattering system offers a rapid, label-free alternative but traditionally relies on complex lasers and analysis. Our enhanced approach utilizes RGB light emitting diodes (LEDs) as the light source. Three diffraction images of bacterial colonies from different LED colors are separately captured by a USB camera and combined using an image registration algorithm to enhance image sharpness. Our approach utilizes an object detection model, i.e., YOLOv8, for analysis achieving high-accuracy differentiation between bacterial strains. We demonstrate the effectiveness of this approach, achieving an average accuracy of 97% (mAP50 of 0.97), including accurate discrimination of closely related strains and the significant pathogen Staphylococcus aureus MRSA 1320. Our enhancement offers advantages in affordability, usability, and seamless integration into existing workflows, providing an alternative for rapid bacterial identification.

The Integration of Gold Nanoparticles into Dental Biomaterials as a Novel Approach for Clinical Advancement: A Narrative Review.

Gold nanoparticles (AuNPs) have gained significant attention in the biomedical field owing to their versatile properties. AuNPs can be customized by modifying their size, shape and surface characteristics. In recent years, extensive research has explored the integration of AuNPs into various dental materials, including titanium, polymethylmethacrylate (PMMA) and resin composites. This review aims to summarize the advancements in the application of modified AuNPs in dental materials and to assess their effects on related cellular processes in the dental field. Relevant articles published in English on AuNPs in association with dental materials were identified through a systematic search of the PubMed/MEDLINE, Embase, Scopus and ScienceDirect databases from January 2014 to April 2024. Future prospects for the utilization of AuNPs in the field of dentistry are surveyed.

Micro/Nano Structural Investigation and Characterization of Mussel Shell Waste in Thailand as a Feasible Bioresource of CaO.

Mussel shell waste, which is regularly disposed by households, restaurants, markets, or farms, causes environmental problems worldwide, including in Thailand, because of its long decomposing time. Owing to a large amount of calcium (Ca) content from calcium carbonate (CaCO3) in mussel shell waste, many Thai local businesses grind the shell waste into powder and sell it as a source of Ca. Generally, these powdered waste shells are a mixture of various types of mussel shell waste. In this study, we investigated and characterized powdered mixed waste shells sold in a local Thai market (called mixed shell powder) and ground shells from waste green mussel shells (called green mussel shells) prepared in the laboratory after calcination at different temperatures (800 °C, 900 °C, and 1000 °C). Mixed shell powder containing five different types of mussel shells and green mussel shells were calcined for 2 h and 3 h, respectively. The time used for calcination of mixed shell powder and green mussel shells was different due to the different particle sizes of both shell wastes. We found that an optimal temperature of 1000 °C completely converted CaCO3 to CaO in both samples. The nanoscale size of CaO was detected at the surface of calcined shells. These shell wastes can be used as a bioresource of CaO.

Colorimetric Sensing of Gram-Negative and Gram-Positive Bacteria Using 4-Mercaptophenylboronic Acid-Functionalized Gold Nanoparticles in the Presence of Polyethylene Glycol.

Gold nanoparticles (GNPs) have been used as detection probes for rapid and sensitive detection of various analytes, including bacteria. Here, we demonstrate a simple strategy for bacterial detection using GNPs functionalized with 4-mercaptophenylboronic acid (4-MPBA). 4-MPBA can interact with peptidoglycan or lipopolysaccharides present in bacterial organelles. After the addition of a high concentration of sodium hydroxide (NaOH), the functionalization of the surface of 50 nm GNPs with 4-MPBA (4-MPBA@GNPs) in the presence of polyethylene glycol results in a color change because of the aggregation of 4-MPBA@GNPs. This color change is dependent on the amount of bacteria present in the tested samples. Escherichia coli (E. coli) K-12 and Staphylococcus aureus (S. aureus) are used as Gram-negative and Gram-positive bacterial models, respectively. The color change can be detected within an hour by the naked eye. A linear relationship is observed between bacterial concentrations and the absorbance intensity at 533 nm; R 2 values of 0.9152 and 0.8185 are obtained for E. coli K-12 and S. aureus, respectively. The limit of detection of E. coli K-12 is ∼2.38 × 102 CFU mL-1 and that of S. aureus is ∼4.77 × 103 CFU mL-1. This study provides a promising approach for the rapid detection of target Gram-negative and Gram-positive bacteria.

Thermal Effect during Laser-Induced Plasmonic Heating of Polyelectrolyte-Coated Gold Nanorods in Well Plates.

We examined the generation and transfer of heat when laser irradiation is applied to water containing a suspension of gold nanorods coated with different polyelectrolytes. The ubiquitous well plate was used as the geometry for these studies. The predictions of a finite element model were compared to experimental measurements. It is found that relatively high fluences must be applied in order to generate biologically relevant changes in temperature. This is due to the significant lateral heat transfer from the sides of the well, which strongly limits the temperature that can be achieved. A 650 mW continuous-wave (CW) laser, with a wavelength that is similar to the longitudinal plasmon resonance peak of the gold nanorods, can deliver heat with an overall efficiency of up to 3%. This is double the efficiency achievable without the nanorods. An increase in temperature of up to 15 °C can be achieved, which is suitable for the induction of cell death by hyperthermia. The nature of the polymer coating on the surface of the gold nanorods is found to have a small effect.

Recent Update Roles of Magnetic Nanoparticles in Circulating Tumor Cell (CTC)/Non-CTC Separation.

Metastasis of cancer is a major cause of death worldwide. Circulating tumor cells (CTCs) are important in the metastatic process of cancer. CTCs are able to circulate in the bloodstream. Therefore, they can be used as biomarkers of metastasis. However, CTCs are rare when compared to a large number of blood cells in the blood. Many CTC detection methods have been developed to increase CTC detection efficiency. Magnetic nanoparticles (MNPs) have attracted immense attention owing to their potential medical applications. They are particularly appealing as a tool for cell separation. Because of their unique properties, MNPs are of considerable interest for the enrichment of CTCs through CTC or non-CTC separation. Herein, we review recent developments in the application of MNPs to separate CTCs or non-CTCs in samples containing CTCs. This review provides information on new approaches that can be used to detect CTCs in blood samples. The combination of MNPs with other particles for magnetic-based cell separation for CTC detection is discussed. Furthermore, different approaches for synthesizing MNPs are included in this review.

Comparison of Single- and Mixed-Sized Gold Nanoparticles on Lateral Flow Assay for Albumin Detection.

The sensitivity and reproducibility of the lateral flow assay can be influenced by multiple factors, such as the size of gold nanoparticles (GNPs) employed. Here, we evaluated the analytical performance of single-sized and mixed-sized GNPs using a simple lateral flow assay (LFA) platform. This platform was used as a model assay to diagnose albumin levels and demonstrate the analytical performance of single-sized and mixed-sized GNPs in LFA tests. Two sizes of GNPs@anti-bovine serum albumin (BSA) conjugate proteins were mixed at different ratios. The unique optical properties of the GNPs induced a distinguishing color-shedding effect on the single- and mixed-sized GNPs@anti-BSA conjugates interacting with the target analyte BSA spotted on the test line. The use of mixed-sized GNPs@anti-BSA conjugates enhanced signal relative to the 20 nm GNPs, and provided superior stability compared with solely employing the large GNPs (50 nm). The proposed platform in this study could provide an efficient BSA detection mechanism that can be utilized as a model biomarker for confronting chronic kidney disease.

In vitro cytotoxicity of RAFT polymers.

The RAFT technique has been increasingly used to generate polymers for potential biological applications. However, to-date, the toxicity of the RAFT-polymers has received limited attention. In this study, the in vitro cytotoxicity of three different, RAFT-synthesized, water-soluble polymers was investigated using three different adherent cell lines via CellTiter-Blue cell viability and the cytosolic enzyme lactate dehydrogenase (LDH) cytotoxicity assays. In brief, P(OEG-A) and P(OEG-MA) samples bearing omega-dithiobenzoate or omega-trithiocarbonate end groups and varying P(HPMA) samples bearing omega-dithiobenzoate, omega-trithiocarbonate, or non-RAFT end groups, were investigated using Chinese hamster ovary cells (CHO-K1), mouse macrophage cells (Raw264.7), and mouse fibroblast cells (NIH3T3). Any changes in the morphology of the cells after treatment with polymers were monitored via microscopy. The cytotoxicity of the polymers after treatment with metabolic liver enzymes was also evaluated. The average viability of CHO-K1 and NIH3T3 cells treated with dithiobenzoate- and trithiocarbonate-ended OEG-based polymers (1000 microM) for 24 h was close to 100%. The RAW264.7 cells were slightly more sensitive when incubated with dithiobenzoate-ended polymers (cell viability above 73%) for 24 h. The viability of the cells after 3 days of incubation with the polymers either slightly decreased or showed no change with respect to the viabilities obtained after 1 day of incubation. Analyses of cell morphology and cell membrane integrity via microscopy and a LDH assay confirmed the cell viability results obtained via CellTiter-Blue Assay. Unexpectedly, dithiobenzoate-ended P(HPMA) (at 1000 microM) exhibited high cytotoxicity after 24 h with all three cells lines. Further investigation of various P(HPMA) samples revealed that trithiocarbonate-ended and HPMA-capped P(HPMA)s at the same concentration were nontoxic over the same period of time. Also, dithiobenzoate-ended P(HPMA) at low concentrations (< or = 200 microM) can be tolerated by the cells tested.

[Theragnostic approaches using gold nanorods and near infrared light].

Gold nanoparticles have unique optical properties such as surface-plasmon and photothermal effects. Such properties have resulted in gold nanoparticles having several clinical applications. Gold nanorods (which are rod-shaped gold nanoparticles) show a surface plasmon band in the near-infrared region. They have therefore been proposed as contrast agents for bioimaging, or as heating devices for photothermal therapy. Polyethylene glycol-modified gold nanorods systemically administrated into mice can be detected with integrating sphere, and the stability of the gold nanorods in blood flow evaluated. After intravenous injection of gold nanorods followed by near-infrared laser irradiation, significant tumor damage triggered by the photothermal effect was observed. To deliver gold nanorods to the target tissue, thermosensitive polymer gel-coated gold nanorods were prepared. After intravenous injection of the gel-modified gold nanorods and irradiation of the tumor, a larger amount of gold was detected in the irradiated tumor than in the non-irradiated tumor. This effect is due to the hydrophobic interaction between the cellular membrane or the extracellular matrix and the gel surfaces induced by the photothermal effect. Furthermore, the photothermal effect enhanced the permeability of the stratum corneum of the skin. As a result of treatment of the skin with ovalbumin and gold nanorods followed by near-infrared light irradiation, a significant amount of protein was detected in the skin. The gold nanorods therefore showed several functions as a photothermal nanodevice for bioimaging, thermal therapy, and a drug delivery system.

Single and multiple detections of foodborne pathogens by gold nanoparticle assays.

A late detection of pathogenic microorganisms in food and drinking water has a high potential to cause adverse health impacts in those who have ingested the pathogens. For this reason there is intense interest in developing precise, rapid and sensitive assays that can detect multiple foodborne pathogens. Such assays would be valuable components in the campaign to minimize foodborne illness. Here, we discuss the emerging types of assays based on gold nanoparticles (GNPs) for rapidly diagnosing single or multiple foodborne pathogen infections. Colorimetric and lateral flow assays based on GNPs may be read by the human eye. Refractometric sensors based on a shift in the position of a plasmon resonance absorption peak can be read by the new generation of inexpensive optical spectrometers. Surface-enhanced Raman spectroscopy and the quartz microbalance require slightly more sophisticated equipment but can be very sensitive. A wide range of electrochemical techniques are also under development. Given the range of options provided by GNPs, we confidently expect that some, or all, of these technologies will eventually enter routine use for detecting pathogens in food. This article is categorized under: Diagnostic Tools > Biosensing.

Prospects for gold nanorod particles in diagnostic and therapeutic applications.

Rod-shaped gold nanoparticles ('nanorods') have recently attracted widespread attention due to their unique optical properties and facile synthesis. In particular, they can support a longitudinal surface plasmon, which results in suspensions of them having a strong extinction peak in the upper visible or near-infrared parts of the spectrum. The position of this peak can be readily tuned by controlling the shape of the rods. In addition, the surface of the nanorods can be functionalized by a very wide variety of molecules. This has led to interest in their use as selective biomarkers in biodiagnostics or for selective targeting in photothermal thearapeutics. Here, we review the recent advances in the use of gold nanorods in these applications. Additionally, the information available regarding their biocompatibility is discussed.

Detection of Adhesion Molecules on Inflamed Macrophages at Early-Stage Using SERS Probe Gold Nanorods.

In recent years, it has been shown that inflammatory biomarkers can be used as an effective signal for disease diagnoses. The early detection of these signals provides useful information that could prevent the occurrence of severe diseases. Here, we employed surface-enhanced Raman scattering (SERS) probe gold nanorods (GNRs) as a tool for the early detection of inflammatory molecules in inflamed cells. A murine macrophage cell line (Raw264.7) stimulated with lipopolysaccharide (LPS) was used as a model in this study. The prepared SERS probe GNRs containing 4-mercaptobenzoic acid as a Raman reporter to generate SERS signals were used for detection of intracellular adhesion molecule-1 (ICAM-1) in macrophages after treatment with LPS for varying lengths of time. Our results show that SERS probe GNRs could detect significant differences in the expression of ICAM-1 molecules in LPS-treated macrophages compared to those in untreated macrophages after only 1 h of LPS treatment. In contrast, when using fluorescent labeling or enzyme-linked immunosorbent assays (ELISA) to detect ICAM-1, significant differences between inflamed and un-inflamed macrophages were not seen until the cells had been treated with LPS for 5 h. These results indicate that our SERS probe GNRs provide a higher sensitivity for detecting biomarker molecules in inflamed macrophages than the conventional fluorescence and ELISA techniques, and could therefore be useful as a potential diagnostic tool for managing disease risk.

Therapeutic possibilities of plasmonically heated gold nanoparticles.

Nanoparticles of gold, which are in the size range 10-100 nm, undergo a plasmon resonance with light. This is a process whereby the electrons of the gold resonate in response to incoming radiation causing them to both absorb and scatter light. This effect can be harnessed to either destroy tissue by local heating or release payload molecules of therapeutic importance. Gold nanoparticles can also be conjugated to biologically active moieties, providing possibilities for targeting to particular tissues. Here, we review the progress made in the exploitation of the plasmon resonance of gold nanoparticles in photo-thermal therapeutic medicine.

Polyelectrolyte-coated gold nanorods and their biomedical applications.

Gold nanorods (GNRs) have been extensively used in biomedical applications, because of their favourable optical properties. Their longitudinal surface plasmon resonance can be tuned, providing a strong near-infrared (NIR) extinction coefficient peak within the tissue transparency window. However, the modification of the surface of GNRs is essential before they can be used for biomedical applications. The number of GNRs taken up by cells and their biodistribution depend on their surface modification. Here, we review the recent advances in modifying GNR surfaces with polyelectrolytes for biomedical applications. Major polyelectrolytes used to coat GNR surfaces over the past few years and the biocompatibility of polyelectrolyte-coated GNRs are discussed.