Immunogold Nanoparticles for Rapid Plasmonic Detection of C. sakazakii

Aly, M. M.; Domig, Konrad J.; Kneifel, Wolfgang; Reimhult, Erik

doi:10.3390/s18072028

Cited by 18 publications

(11 citation statements)

References 47 publications

(53 reference statements)

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“…This result is slightly above the expected wavelength increase for the formation of pAb–AuNP 43 and is an indication of aggregation. 24,39 Also, the aggregation is confirmed with the AI nearing 1 for the NaOH-11 condition and the broad nature of the UV–vis spectra, which is attributed to the linear aggregation due to dipole interactions. 45…”

Section: Results and Discussionmentioning

confidence: 79%

Optimization and Structural Stability of Gold Nanoparticle–Antibody Bioconjugates

et al. 2019

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Gold nanoparticles (AuNPs) bound with biomolecules have emerged as suitable biosensors exploiting unique surface chemistries and optical properties. Many efforts have focused on antibody bioconjugation to AuNPs resulting in a sensitive bioconjugate to detect specific types of bacteria. Unfortunately, bacteria thrive under various harsh environments, and an understanding of bioconjugate stability is needed. Here, we show a method for optimizing Listeria monocytogenes polyclonal antibodies bioconjugation mechanisms to AuNPs via covalent binding at different pH values, from 2 to 11, and 2-(N-morpholino)ethanesulfonic acid (MES), 3-(N-morpholino)propanesulfonic acid, NaOH, HCl conditions. By fitting Lorentz curves to the amide I and II regions, we analyze the stability of the antibody secondary structure. This shows an increase in the apparent breakdown of the antibody secondary structure during bioconjugation as pH decreases from 7.9 to 2. We find variable adsorption efficiency, measured as the percentage of antibody adsorbed to the AuNP surface, from 17 to 27% as pH increases from 2 to 6 before decreasing to 8 and 13% at pH 7.9 and 11, respectively. Transmission electron microscopy (TEM) analysis reveals discrepancies between size and morphological changes due to the corona layer assembly from antibody binding to single nanoparticles versus aggregation or cluster self-assembly into large aggregates. The corona layer formation size increases from 3.9 to 5.1 nm from pH 2 to 6, at pH 7.9, there is incomplete corona formation, whereas at pH 11, there is a corona layer formed of 6.4 nm. These results indicate that the covalent binding process was more efficient at lower pH values; however, aggregation and deactivation of the antibodies were observed. We demonstrate that optimum bioconjugation condition was determined at pH 6 and MES buffer-type by indicators of covalent bonding and stability of the antibody secondary structure using Fourier transform-infrared, the morphological characteristics and corona layer formation using TEM, and low wavelength shifts of ultraviolet–visible after bioconjugation.

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Section: Results and Discussionmentioning

confidence: 79%

Optimization and Structural Stability of Gold Nanoparticle–Antibody Bioconjugates

et al. 2019

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“…Cronobacter sakazakii is regarded as an opportunistic foodborne pathogen, which can cause meningitis, bacteremia and necrotizing enterocolitis, particularly in infants (Drudy et al, 2006; Aly et al, 2018). Neonates have suffered from life-threatening infections of C. sakazakii within the first 28 days after birth (Mullane et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…However, it is of interest to note that ST4 strains usually have been isolated from powdered infant formula and from milk powder processing factories (van Acker et al, 2001; Siqueira Santos et al, 2013; Sonbol et al, 2013; Gicova et al, 2014). Recently, efforts have been made to develop rapid detection schemes for Cronobacter species in food samples (Aly et al, 2018, 2019; Pan et al, 2018). Such technologies would greatly enhance food safety by allowing for continuous monitoring of contamination in the food chain.…”

Section: Introductionmentioning

confidence: 99%

Whole Genome Sequencing-Based Comparison of Food Isolates of Cronobacter sakazakii

et al. 2019

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Cronobacter sakazakii is an emerging foodborne pathogen, which is linked to life-threatening infections causing septicemia, meningitis, and necrotizing enterocolitis. These infections have been epidemiologically connected to ingestion of contaminated reconstituted powder infant formula. Even at low water activity C. sakazakii can survive for a long time; it is capable of protective biofilm formation and occasionally shows high virulence and pathogenicity even following stressful environmental conditions. Hence it is a challenging task for the food industry to control contamination of food ingredients and products through the entire production chain, since an increasing number of severe food-related outbreaks of C. sakazakii infections has been observed. The seemingly great capability of C. sakazakii to survive even strict countermeasures combined with its prevalence in many food ingredients requires a greater in depth understanding of its virulence factors to master the food safety issues related to this organism. In this context, we present the whole genome sequence (WGS) of two different C. sakazakii isolated from skimmed milk powder (C7) and ready-to-eat salad mix (C8), respectively. These are compared to other, already sequenced, C. sakazakii genomes. Sequencing of the fusA allele revealed that both isolates were C. sakazakii . We investigated the molecular characteristics of both isolates relevant for genes associated with pathogenesis and virulence factors, resistance to stressful environmental conditions (e.g., osmotic and heat), survival in desiccation as well as conducted a comparative genomic analysis. By using multi-locus sequence typing (MLST), the genetic type of both isolates is assessed and the number of unique genes is determined. DNA of C. sakazakii C8 is shown to hold a novel and unique sequence type; the number of unique genes identified in the genomic sequence of C. sakazakii C7 and C8 were 109 and 188, respectively. Some of the determined unique genes such as the rhs and VgrG genes are linked to the Type VI Secretion System cluster, which is associated with pathogenicity and virulence factors. Moreover, seven genes encoding for multi-drug resistance were found in both isolates. The finding of a number of genes linked to producing capsules and biofilm are likely related to the observed resistance to desiccation.

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“…This helps in rapid screening with a detection limit of <50 pg g− 1 [ 216 ]. Aly et al [ 132 ] designed an immunoassay using gold nanoparticles grafted with PEG and functionalized with polyclonal antibodies raised against C. sakazakii to specifically target them. The specific binding of nanoparticles with cells was verified using transmission electron microscopy.…”

Section: Nanomaterials and Their Clinical Applicationmentioning

confidence: 99%

Broad-Spectrum Theranostics and Biomedical Application of Functionalized Nanomaterials

Alshamrani

2022

Polymers

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Nanotechnology is an important branch of science in therapies known as “nanomedicine” and is the junction of various fields such as material science, chemistry, biology, physics, and optics. Nanomaterials are in the range between 1 and 100 nm in size and provide a large surface area to volume ratio; thus, they can be used for various diseases, including cardiovascular diseases, cancer, bacterial infections, and diabetes. Nanoparticles play a crucial role in therapy as they can enhance the accumulation and release of pharmacological agents, improve targeted delivery and ultimately decrease the intensity of drug side effects. In this review, we discussthe types of nanomaterials that have various biomedical applications. Biomolecules that are often conjugated with nanoparticles are proteins, peptides, DNA, and lipids, which can enhance biocompatibility, stability, and solubility. In this review, we focus on bioconjugation and nanoparticles and also discuss different types of nanoparticles including micelles, liposomes, carbon nanotubes, nanospheres, dendrimers, quantum dots, and metallic nanoparticles and their crucial role in various diseases and clinical applications. Additionally, we review the use of nanomaterials for bio-imaging, drug delivery, biosensing tissue engineering, medical devices, and immunoassays. Understandingthe characteristics and properties of nanoparticles and their interactions with the biological system can help us to develop novel strategies for the treatment, prevention, and diagnosis of many diseases including cancer, pulmonary diseases, etc. In this present review, the importance of various kinds of nanoparticles and their biomedical applications are discussed in much detail.

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Immunogold Nanoparticles for Rapid Plasmonic Detection of C. sakazakii

Cited by 18 publications

References 47 publications

Optimization and Structural Stability of Gold Nanoparticle–Antibody Bioconjugates

Optimization and Structural Stability of Gold Nanoparticle–Antibody Bioconjugates

Whole Genome Sequencing-Based Comparison of Food Isolates of Cronobacter sakazakii

Broad-Spectrum Theranostics and Biomedical Application of Functionalized Nanomaterials

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