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.

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.

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.

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.

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.

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.

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.

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.

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.