Mini Review - Advanced Materials Science Research (2022) Volume 5, Issue 6

Polyphenolic Alkaline Magnetic Nanoparticles are Oxidizing Agents that Destroy Microbes

Asfaq Faij*

Department of Material Science and Nano Material, India

*Corresponding Author:
Asfaq Faij
Department of Material Science and Nano Material, India

Received: 01-Dec-2022, Manuscript No. AAAMSR-22-83424; Editor assigned: 05-Dec-2022, Pre-QC No. AAAMSR-22-83424 (PQ); Reviewed: 19-Dec-2022, QC No. AAAMSR-22-83424; Revised: 24-Dec-2022, Manuscript No. AAAMSR-22-83424 (R); Published: 31-Dec-2022; DOI: 10.37532/ aaasmr.2022.5(6).127-131


The function of the microbiome in chronic rhinosinusitis (CRS) is unknown. For acute disease exacerbations (AECRS), antibiotics are advised. Silver nanoparticles (AgNPs), an alternative treatment option, have been the focus of antibiotic resistance research. However, the Silver administration’s security is a concern. The biological activity of tannic acid-prepared AgNPs (TA-AgNPs) toward sinonasal pathogens and nasal epithelial cells (HNEpC) was the primary focus of this investigation. The well diffusion method was used to approximate the pathogens’ minimal inhibitory concentration (MIC) that were isolated from AECRS patients. A MTT assay and trypan blue exclusion were used to assess TAAgNPs’ cytotoxicity. Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Klebsiellaoxytoca, Acinetobacter baumannii, Serratia marcescens, and Enterobacter cloacae were among the 48 clinical isolates and four reference strains included in the study. The investigations revealed that the MIC values varied between segregates, even within species that are similar. After 24 hours of exposure, all of the isolates were sensitive to TA-AgNPs at concentrations that did not harm human cells. However, HNEpC’s therapeutic window was narrowed because 19% of pathogens were able to resist the biocidal action of the TA-AgNPs after 48 hours of exposure. TA-AgNPs were viewed as non-harmful to the analyzed eukaryotic cells and successful against most of microorganisms separated from patients with AECRS after brief openness; however, sensitivity testing may be required prior to application.


Chronic rhinosinusitis • Exacerbations • Microbiome • Microbiota • Bacteria • Antibiotic resistance • Silver nanoparticles • Tannic acid


The irritation of the sinus mucosa prompts ongoing rhinosinusitis (CRS). Understanding the intricate connections between the inflammatory process and the sinus microbiota is still in its infancy. During severe intensifications of ongoing rhinosinusitis (AECRS), the function of microbes appears to be more apparent. Antibiotic treatment is advised if purulent sinus symptoms accompany the sudden deterioration of symptoms. The problem is a bacterial infection. One of the factors that reduces the effectiveness of AECRS treatment is sinus pathogen resistance to antibiotics. As a consequence of this, more and more people are opting for novel treatments [1].

Silver nanoparticle (AgNP) intranasal preparations have been proposed as an alternative treatment for sinonasal infections in the event that antibiotic therapy is ineffective. The physicochemical and biological properties of AgNPs, which can take on any form and have dimensions ranging from 10-9 m to 10-7 m, are significantly influenced by the methods and stabilizing agents used to synthesize them. Silver atoms are what make AgNPs. The dispersed AgNPs in liquid media are sometimes referred to as “colloidal silver.” Notwithstanding, disarray could result from this term’s equivocalness. Instead of clearly defined silver nanoparticles, many over-the-counter products marketed as “colloidal silver” contain various obscure types of silver [2].

Regarding the potential medical applications of AgNPs, either reservations or enthusiasm have been expressed. Silver’s antimicrobial properties have long been known. A wide range of microorganisms, including yeast, fungi, and bacteria with Gram-positive and Gram-negative symbionts, have been shown to be resistant to silver [3]. It was thought that developing resistance to silver was extremely unlikely due to its damage to numerous essential cell structures. Sadly, ongoing research has shown that a variety of silver-opposing components can be produced by microorganisms, some of which also cause antimicrobial cross-obstruction. The research into AgNP’s harmfulness has produced inconsistent results [4]. In some studies, preparations made with AgNP were found to be safe. despite the fact that other studies have demonstrated that the drug accumulates in many organs, including the brain, and causes cytotoxicity when administered through the nose. There are no reliable data on the most effective route of administration for sinonasal infections, despite the fact that the dosage and formulation of AgNPs have an impact on their toxicity [5].

According to ongoing research, clinical isolates of microorganisms occasionally exhibit silver obstruction properties and can withstand extremely high silver fixations. The idea that silver is an all-purpose antimicrobial that can treat any infection without first going through sensitivity testing is cast into doubt by these results. The frequency of silver obstruction in human contaminations is unknown due to the absence of routine screening [6].

However, a number of published studies have shown that the science of the settling layers and the surface charge of AgNPs have a significant impact on their biocidal movement. Altering the surface properties of AgNPs can be done with a wide variety of stabilizing agents [7]. It would appear that AgNPs covered with standard mixtures with the best organic action would benefit greatly from clinical applications. The stability and usefulness of AgNPs capped by a variety of polyphenol molecules have been the focus of recent research. Core-shell-coated polyphenol AgNPs, for instance, demonstrated antimicrobial and antioxidant properties [8]. AgNPs with polyphenol caps were also found to be biocompatible at low concentrations. As a response, they discovered that AgNPs, polyphenol biomolecules, and chitosan work together to produce synergistic antibacterial effects [9].

Tannic corrosive (TA) appears to be one of the center sub-atomic mass polyphenols associated with the design of AgNPs that is most wellknown and used frequently. At the synthesis level of AgNP, TA serves two purposes: It reduces silver ions and stabilizes newly formed nanoparticles. From a biological point of view, TA is a wellknown antibacterial and antiviral agent. It is essential to note that TA is also a promising candidate for inhibiting and preventing SARSCoV- 2 infection. It was demonstrated that TA was effective against HIV, herpes simplex viruses (types 1 and 2), and Noroviruses among other viruses. However, it has been demonstrated that TA is effective against both Gram-positive and Gram-negative bacteria, including other strains of Staphylococcus aureus, Escherichia coli, Yersinia enterocolitica, and Listeria innocua [10].

Union and physicochemical qualities of TAAgNPs

Under alkaline conditions, silver ions delivered by TA in the form of silver nitrate were chemically reduced into TA-AgNPs [11]. In contrast to other standard preparation protocols, no additional stabilizing agents were utilized. TA-AgNPs were separated from unreacted compounds and placed in an aqueous suspension using the ultrafiltration technique that was previously described in detail [12]. Thickness estimations and inductively coupled plasma optical discharge spectrometry (ICP-OES) were utilized to find out the stock suspension’s mass centralization of TA-AgNPs. The mass concentration of TAAgNPs in the stock suspension was 217 3 mg L1. After the purification process, there were no silver ions in the stock suspension. The end product was a suspension with a pH of 5.8 [13]. The suspension had a very vivid yellow color. When the mass concentration of TA-AgNP in the aqueous suspension was increased, the absorbance value at a wavelength of 412 nm was typically observed to rise. This result is in line with other studies that have been published and show that the colloidal suspension’s silver content increases absorption [14].

Isolates of bacteria

Fifty patients who had experienced acute exacerbations of chronic rhinosinusitis (AECRS) were the subjects of swabs taken from the sinonasal cavity. There were 23 men and 27 women in the group, with ages ranging from 25 to 80 (mean age 51). Since each patient had undergone endoscopic sinus surgery previously, it was possible to obtain samples from their sinuses. Chronic rhinosinusitis, nasal polyps, and comorbid conditions like asthma (54 percent), aspirin-exacerbated respiratory disease (10 percent), or allergy accounted for the majority of participants (90 percent). 48 of the 97 withdraws were investigated to check whether they were TA-AgNP-fragile. Nonpathogenic and microscopic media-dependent TA-AgNPrepressing microorganisms were banned [15].


The sensitivity of sinus pathogens to tannic acid (TA)-based AgNPs was the primary focus of this investigation. The TA-AgNPs watery suspension was gotten as per laid out planning conventions. TA-AgNPs have a negative zeta potential and a shape that is close to spherical, according to their physicochemical properties. comparing the reports in the literature with the experimental data. We assumed that the AgNPs’ status could be replicated using TA. It was established that AgNPs with controlled properties could be made with TA.

The evaluation of their bactericidal properties was the primary focus due to the presence of clearly defined TA-AgNPs. The minimal inhibitory concentration (MIC) was approximated using the well diffusion method. The clinical segregates’ MIC advantages increased from 5 to 40 mg L1. The qualities announced by different creators for similar bacterial species contrast between concentrates because of contrasts in the sorts of AgNPs, bacterial strains, and responsiveness testing techniques utilized. investigated the antimicrobial properties of AgNPs that were prepared with tannic acid and were comparable to those used in our study. A reference strain of P. aeruginosa had MIC values of 64 mg L-1, whereas reference strains of S. aureus, E. coli, K. pneumoniae, and A. baumannii had MIC values greater than 64 mg L-1. However, they used the disk diffusion technique, in which paper discs were submerged in the TA-AgNPs solution and then placed on top of bacteria-infested agar. It was discovered that our research’s well diffusion method was more sensitive than this one. It is unknown how quickly AgNPs diffuse from the paper disks to the agar. As a result, it’s possible that the disc’s surrounding medium contains significantly fewer TA-AgNPs than the solution’s initial concentration. The well dispersion strategy probably results in a higher grouping of nanoparticles around the well than around the paper plate. We are aware that it could still be lower than the stock suspension’s initial concentration. As a result of this, the “MIC” esteem that was laid out through our examination should be viewed as the furthest reaches of the genuine MIC (showing that the genuine MIC doesn’t surpass the most minimal fixation in the well that is dependent upon a zone of hindrance). However, the disk diffusion method is less accurate than the well diffusion method for MIC approximations.

Additionally, it is common practice to use a single reference strain when discussing animal classifications. Our research reveals that this tactic is flawed. We demonstrated that clinical isolates of the same species did not have the same levels of sensitivity to AgNPs as reference strains. The reference strains of S. aureus, E. coli, and K. pneumoniae had upper limit MIC values that were two to five times lower than the median values of the clinical isolates. In contrast, clinical segregates of the same species were exemplified by MIC values that were twice as high at the extremes as they were at the middle of the reference P. aeruginosa. The upper limit of MIC values varied significantly among species-identical clinical isolates. The species had no effect on these distinctions. We found isolates that were only inhibited by much higher antimicrobial concentrations (40 mg L1) for the majority of species, and we also found isolates that were extremely sensitive to TA-AgNPs (MIC 5 mg L1).

We also investigated the possibility of using the TA in TA-AgNPs to kill bacteria. Tests on two reference strains — E. coli and S. aureus — affirmed that TA represses bacterial development. However, the bacteria in the TA-AgNPs experiments were exposed to concentrations above which the effect was only observable at extremely high TA concentrations (55 M, or 94 mg L-1). Tae Yoon Kim and others’ findings are in line with the high value of the MIC. who mentioned that a few reference strains had TA MICs ranging from 53 to 425 mg L1. The results of our previous experiments suggested that TA and AgNPs work together: The antibacterial activity of TA-AgNPs was superior to that of other AgNPs that had been functionalized by different specialists. However, the functionalizing agent also has an effect on the AgNP size, charge, and stability; As a result, cautious conclusions regarding potential synergy should be drawn.

It has been demonstrated that the interactions between Gram-positive and Gram-negative bacteria and metal nanoparticles are influenced by the structure of the cell walls. Gram-negative E. coli was found to be more susceptible to AgNPs than Gram-positive S. aureus in a number of studies. MIC values that range from two to ten times lower, depending on the study. However, despite the fact that there were no statistically significant differences in MIC values between Gram-positive and Gram-negative bacteria in our study, the mean MIC value for isolates of Gram-positive bacteria was lower than that of isolates of Gram-negative bacteria. Negative zeta potentials were observed in all of the TAAgNPs used in our study and those described by other researchers. As a result, it is reasonable to assume that AgNPs and LPS engage in repellent electrostatic interactions within the cell wall of Gram-negative bacteria. However, experiments revealed that these electrostatic interactions have no effect on the AgNPs’ bactericidal activity. Several studies have shown that TA-synthesized AgNPs are very good at killing bacteria and getting rid of microbial biofilms.

Prior to this, the effectiveness of AgNPs against clinical isolates from CRS and otitis patients was evaluated. The AgNPs were produced using Corymbia maculate extract. The study examined 18 distinct bacterial strains, including five each of MRSA, P. aeruginosa, H. influenzae, and S. pneumoniae, as well as five each of those four species. P. aeruginosa was the only species that was more sensitive to the AgNPs than any other species, despite the fact that Gram-positive isolates did not always outperform Gramnegative bacteria in terms of resistance. The authors also noted that the MIC values for each species based on the strain varied. Despite the fact that their AgNPs were different from ours, the findings of the Australian study and our European observations were strikingly similar. Both studies demonstrated that it is impossible to predict the sensitivity of sinonasal pathogens to AgNPs. If AgNPs are used in therapy, each patient’s isolate needs to be tested individually to see if it may be resistant.

Recent observations indicate that sublethal exposure and the development of resistance may result from the uncontrolled application of silver without prior knowledge of the pathogen’s sensitivity. It has been demonstrated that exposure to increasing silver concentrations can quickly induce resistance, so silver preparations should be used with caution. Bacteria can repel Silver and AgNPs through a variety of resistance mechanisms. They must only be used when antimicrobial treatment is clearly indicated, and their dosage must be sufficient to reach concentrations above the targeted pathogen’s MIC values.


The majority of pathogens isolated from CRS patients during episodes of exacerbations were, in conclusion, sensitive to TA-AgNPs in vitro at concentrations safe for the nasal epithelium. However, it’s possible that the in vitro tests underestimated or overestimated antimicrobial toxicity. Before AgNPs can be used as intranasal antimicrobials in humans, further in vivo studies on pharmacokinetics, pharmacodynamics, and toxicity are required.Testing for sensitivity to AgNPs ought to be performed in every instance prior to their application due to the significant variation in MIC values between isolates and their unpredictability. This strategy might prevent exposure to low-quality drug concentrations that encourage the growth of silver resistance.


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