Biosynthesis and Characterization of Zinc Oxide Nanoparticles and Their Impact on the Composition of Gut Microbiota in Healthy and Attention-Deficit Hyperactivity Disorder Children.

Guoling Zhou,Rongrong Yu,Khaled S Allemailem,Hubiao Jiang,Luqiong Lv,Temoor Ahmed,Muchen Zhang,Fahad A Alhumaydhi,Bin Li

doi:10.3389/fmicb.2021.700707

Abstract

Attention-deficit hyperactivity disorder (ADHD) seriously affects children’s health, and the gut microbiome has been widely hypothesized to play a role in the regulation of ADHD behavior. The present study aims to the biosynthesize of zinc oxide nanoparticles (ZnONPs) by using Acinetobacter johnsonii strain RTN1, followed by their characterization through state-of-the-art material characterization techniques, viz., UV–vis spectroscopy, Fourier transform infrared spectroscopy, and transmission and scanning electron microscopic analyses with energy dispersive spectrometry. Moreover, we investigated and compared the population composition of gut microbiota and their susceptibility to biogenic ZnONPs between healthy and ADHD children based on the traditional plate method and 16S rRNA amplicon sequence analysis. The antibacterial effect of ZnONPs against gut bacteria was also determined by measurement of live cell number, living/dead bacterial staining test, and flow cytometry observation. The present study revealed that the number of live gut bacteria in healthy children was more than 10-fold higher than that in ADHD children; however, the community structure of gut bacteria has changed, while greater diversity was found in gut bacteria from ADHD children. In addition, we found that the number of live gut bacteria in healthy and ADHD children was reduced by ZnONPs, which shows an increased and reduced effect in composition of gut bacteria from healthy and ADHD children, respectively. It was also noted that the main mechanism of ZnONPs may be to inhibit the growth of gut bacteria rather than to kill them, while the nanoparticle-resistant strains in healthy children is also different from that in ADHD children. Some representative bacteria, in particular nanoparticle-resistant bacteria, were successfully isolated and identified. Overall, this study revealed the potential correlation of ADHD with gut bacteria and provided a new possibility to prevent ADHD by the combination of nanoparticle and its resistant bacteria.

Highlights

Attention-deficit hyperactivity disorder (ADHD) is one of the most prominent developmental and neuropsychiatric disorders characterized by problems with inattention, impulsivity, and hyperactivity, which have been increasingly diagnosed in the last decade and affects approximately 8–12% of school-aged children worldwide (Luo et al, 2019)
Biogenic zinc oxide nanoparticles (ZnONPs) were extracellularly synthesized by using a bacterial strain RTN1, and the maximum precipitate clustered at the bottom of the flask was determined at 0.1 M ZnSO4·7H2O concentration
The production of ZnONPs was further confirmed by the UV–vis absorption peak measured at 361 nm (Figure 1A), which is in agreement with the study of Malaikozhundan et al (2017), who synthesized the Bacillus thuringiensis-coated ZnONPs and observed the UV–vis spectral peak at 373 nm, which is consistent with our study

Summary

Introduction

Attention-deficit hyperactivity disorder (ADHD) is one of the most prominent developmental and neuropsychiatric disorders characterized by problems with inattention, impulsivity, and hyperactivity, which have been increasingly diagnosed in the last decade and affects approximately 8–12% of school-aged children worldwide (Luo et al, 2019). Children with ADHD are extremely active and unable to concentrate on anything for very long, with the result that they find it difficult to learn and often behave in inappropriate ways (Wang et al, 2020). There is growing evidence supporting the role of the human gut microbiome in the development of ADHD (Sampson and Mazmanian, 2015; Boonchooduang et al, 2020). The brain–gut axis theory proposes that the gut microbiota can influence brain function and behaviors through involvement in physiological homoeostasis, immunological development, glutathione metabolism, amino acid metabolism, etc (De Vadder et al, 2014). It is necessary for us to investigate the change in the composition of gut microbiome from ADHD children, which will provide a new insight to elucidate the mystery of this complex disease

Objectives

Methods

Results

Conclusion