It is crucially more difficult to treat infected root canals than root canals which are not infected   ( Ørstavik, 2004). In these conditions, bacteria can elude cleaning , shaping and penetrate into dentinal tubules which reach to 300 microns maximum length. Moreover, it can build  biofilms, that can protect it from chemical-mechanical treatments and greatly rise its resistance in comparison to the planktonic state ( Elkillany, et al., 2022).  Although chemo mechanical endodontic treatments can decrease the amount of microorganisms within the root canal the complete removal has not been done yet. The majority of  intra canal disinfectants are  not effective against bacterial biofilm because root canal system have a very complex anatomy and the natural microbiological elements.  Endodontic studies  have exhibited that  during the filling process, not  all root canal surfaces can touché  by root canal files, but 35% of them stay untouched .(Nair, et al., 2018 ). E.faecalis is the  most abundant in root canals. (Kouidhi et al., 2011  ). Despite  this bacteria is  not considered as a typical flora, but it  appeared in dental decay, infection of root canals and periodontitis. E.faecalis have high resistance in oral cavity and  considered as the main  reason of endodontic  failure ( Mallah  and Al-Naimi, 2021).  Sodium hypochlorite (NaOCl) is the first choice of medication that is used   in root canals. Due  to  its strong  antibacterial action  and  the elimination  of  organic materials plus tissue remains (Xia et al., 2022). CHX is the most popular choice of  root canal irrigation because of its antibacterial activity with  high substantively that leads to a longer  action ( Elkillany et al., 2022) .According to (Mirhadi et al., 2015 ), it can be said that none of the chemicals which used in irrigation  can consider  as the best choice, thus, continuous  studies in endodontic field  is being  achieved  to find another medicaments that have better antimicrobial action and minimal side effects, so fresh  irrigation  are required.  Newly,  nanotechnology which  is a new branch of Nano science  have introduce a new progression  in prevention and treatment of dental infections, due to their  properties  which increased  the application of this science in endodontic field ,  these properties include  extremely small size and highly useful surface area to mass ratio , mechanical, physical, chemical and biological properties  (Raura et al., 2020 ).  Chitosan is a hopeful natural polymer which have antimicrobial effect, at the same time their biocompatibility and  nontoxicity introduce chitosan as a perfect substance in medical ( Yan et al., 2021 ). As GRAS,   by the US Food & Drug Administration, Chitosan has been  granted  as license   ( Garg et al., 2019, Mo et al,. 2015 ). The inorganic nanoparticles ,wide spread use of Titanium dioxide (TiO2) in  recent years  , due to their   toxicity  mechanism against  a variety of  bacteria including G+ and G- bacteria( Jha et al ., 2011 ,  Dicastillo ,et al.,  2019) , low cost, distinct  physio-chemical characteristics and thermal stability ( Banu et al., 2014 ) .  Our research used colony-forming units (CFU) to compare  the effectiveness of Cs-NPs and TiO2-NPs as an antimicrobial endodontic treatment and comparing them with currently used chemical modalities 

 1- Preparaation of nanoparticles solutions

  As per (Sankar et al., 2023 ), to prepare 10 mg per ml of chitosan solution, dissolve  five hindered mg of chitosan in fifty  ml of acetic acid solution(1%) and agitating  the mixture at 25C0 (1000 rpm \ 25 mints) until a clear solution is obtained. After being sonicated, resulting solution was titrated using Sodium hydroxide  or hydrochloric acid to a obtain PH equivalent to5 . This was followed by filtering the mixture through a 0.2 µ microfilter. Then sonication of resulting solution was done for 5 mins in order to obtain a clear solution, then different concentration of Cs -NPs solution were prepared, including (10 mg/ml, 5mg\ml, 2.5 mg\ml, 1.25 mg\ml and 0.625mg\ml). At the same time preparing of TiO2- NPs nanoparticle solutions  were done by melting the nanoparticle powder in ddw. (Najem et al., 2023 ), then serial dilutions w ere prepared including (2600 µg/ml, 1300 µg/ml, 650µg/ml, 325 µg/ml and162.5  µg/m).

 2-Preparation of E.faecalis inoculums 

 Colonies of E.faeecalis MuAm strain  which was previously isolated from infected root canal and was sequenced & deposited at DDBJ/ENA/GenBank under the accession number (JAUZTE000000000) were  inoculated in a brain heart infusion (BHI) broth  mixing well  by using a vortex; the turbidity of broth matched to McFarland 0.5 standard  in order to fix the no. of bacteria at 1.5×108 ( Sopandani et al., 2020) 

 3- Determination of Minimum inhibitory concentration of Cs-NPs  and TiO2-NPs solutions.

 For determining The MIC of both  nanoparticle solutions, serial tube dilution assay was done.    2ml of  BHI broth were transferred into each of the twenty test tubes, which were then sterilized   for 15 minutes by autoclave at 15 pounds per square inch &121C0,  tubes were divided into 2groups, each group contains 10 test tubes then 2ml of Cs-NPs solutions(10mg\ml) was transferred to the first tube, then  mixed , the next step involved transferred 2 ml of this mixture  to the second tube, then 2 ml were transferred from the second tube to the third tube until reaching to the tenth tube. For TiO2-NPs group,  2ml of 2600µ\ml of TiO2-NPs solution was added to the first tube, the same procedure was repeated  until reached to the tenth tube, after that 2ml was discarded from the last tube of each group, Finally the total tubes were inoculated with 0.1 ml of standard bacterial inoculum of  E. faecalis  EmAm strain, incubated aerobically at 37 C0 for 24 hours. The positive control tubes were contained 100 μl of a standardized bacterial suspension  and  BHI  medium. The negative control tubes were contained sterile BHI media. Tubes which still clear indicated no growth, tubes with turbidity were indicated of bacterial growth. lowest concentration that does not show growth was the MIC (Punjabi et al.,2018) .     

 4- Selection and preparation of sampled roots:  

In this study, thirty healthy human lower premolars, extracted out for orthodontic reasons from patients between the ages of 17 and 24 were used. The teeth are free of root deformities and have perfectly formed apices and virtually straight roots with a single canal. The teeth were kept in a 200 ml solution containing 0.1% thymol(Keine et al.,2019). After that, an ultrasonic scalar was used to clean the teeth in order to get rid of any remaining biological debris, calculus, and plaque from the outer surfaces.  Thereafter, the crown of the teeth was cut using a 0.2 mm thickness diamond disc with a contra-angle handpiece and adequate of water coolant, in order to achieve root length of about 13 mm that was verified with a digital caliper.  The root canals were then opened and the pulp tissues have been removed with a barbed broach, and the working length was determined. ProTaper NEXT rotary files to X3 have been used for the root canal preparation( Velozo et al., 2020). The regimen of irrigation next each file was two ml of 2.5% sodium hypochlorite (NaOCl)  for one minute ,  last irrigation of the canals was performed as in the following steps: Four ml of 2.5% NaOCl for two  minutes , five ml of normal saline   for two minutes,  three ml of  ethylenediamine tetra-acetic acid solution15% (EDTA)   for two minutes, and then the canal was rinsed with ten ml of N.S. for two  minutes.  After the preparation, each root's apex was sealed using a composite resin restorative material. The entire external root surface were covered by two coats of nail varnish  ( Kim et al., 2019), fig (1). 

5-  Teeth Sterilization   

Sampled roots were fixed within the metallic box containing a silicone-based poly vinyl siloxane material, the metalic box containing the inserted roots was  covered  with  aluminum foil, it was then put inside sterilizing sacs. Steam autoclave was used to sterilize the items at 121°C /15 pounds/inch2 for 15 minutes.  

 6-  Inoculation of the root canals  

Brain heart infusion (BHI) was inoculated with E. faecalis EmAm strain in order to inoculate   the teeth samples. 10 µl of the Brain heart broth containing 1.5 x108 E.faecalis) was  pushed into the sterile roots  by using an insulin syringe  (Fig 1) . The syringe needle was pushed up and down in order to make sure that  bacterial suspension was reached  the whole length of the root canal with reducing the air bubbles. All the steps were done under a septic conditions. Finally the sampled roots were incubated at 37oC for 72 hrs. ( Mallah, 2021).

 7- Disinfection of the infected sampled roots  

 Afrter incubation six groups were created from the total sampled roots  

Group A:  included irrigating five canals for five minutes with five milliliters of Cs-NPs suspension (2.5 mg/ml), followed by more five minutes of irrigation with five milliliters of sterile normal saline.  

Group B:  five canals received five minutes of irrigation with five milliliters of  Cs-NPs suspension (2.5 mg/ ml), followed by irrigation with five milliliters of CHX (2%), for further five minutes.

Group C : five canals received five minutes of irrigation with five milliliters of  CHX (2%) for 5 minutes, then  another  five minutes irrigation  with five milliliters of sterile saline. 

Group D:  included of  irrigating five canals with five milliliters of  TiO2-NPs suspension (650µg\ml ) for 5 minutes followed by five minutes of irrigation with five milliliters of sterile normal saline  

Group E : included  irrigating five canals   with 5 milliliters  of  Na OCL (5.25%) for 5 minutes, followed by five milliliters   sterile normal  saline irrigation  for further  five minutes 

Group F (control negative): included irrigating five canals with 10 ml of D.W.  for 10 minutes.

 For  standardization and termination  the  effect of irritant , five milliliters of D.W. were  irrigated within the root canals (Roshdy et al., 2018) by using (A30-gauge needle) of closed apex and  two sides venting  and  at a rate of 5 ml/75 seconds. 

By using a #40 sterile paper points that inserted in root canals for 60 seconds, samples were obtained (Roshdy et al., 2018). Then quickly carried to a sterile test tubes of 1 milliliters normal saline, the solutions were mixed  with a vortex for 60 seconds. Tenfold serial dilutions were performed extending from (10³ - 107), Finally, a duplicate plates of  HiCrom TM Enterococcus faecium Agar base medium were inoculated with  0.1 milliliter of the last diluted suspension, then   CFU\ml were counted after 48 hours of incubation ( Mustafa etal., 2010). 

Statistical analysis:

By using Sigma Stat program (Wayne et al.,2014), all data were examined with a statistically significant value at p<0.05

Fig(1) : Metalic box containing a silicone-based poly vinyl siloxane impression material  which is used to fix the sampled roots (A), Human mandibular premolar (prepared sample) coated with nail polish.(B).

Fig (2): Enterococcus faecalis strain MuAm  count on HiCrom TM Enterococcus faecium    Agar base medium (A) Cs-NP,  (B)(Cs-NP+CHX,  (C) CHX, ((D) TiO2-NP,  (E) Control

negative, ((F) NaOCl  

The Minimum Inhibitory Concentration (MIC) of the two nano particles solutions    toward E. faecalis  MuAm strain is  appear in table (1).

Table (1):  The MIC value  of  each of Cs-NPs and TiNPs solutions against E. faecalis EmAm strain.

Table (2): Descriptive statistics of the surviving colonies calculated from the HiCrom TM Enterococcus faecium Agar  plates  after treating with irrigation materials.

Regarding each tested solution used in this study, there were differences in the bacterial reaction. Table(2) demonstrates the antibacterial effects of two nanoparticle solutions, Cs-NPs and Ti02 NPs, against E. faecalis in comparison to standard intracanal irrigations  .  Cs-NPs , CHX with CS-NPs  and CHX(2%)  solutions provided the lowest mean value of CFU, followed by NaOCL5.25% solution,  while distilled water group produced the highest mean value.   

 According to Tabl(3),  No statistically significant difference was observed  between TiO2NPs  and NaOCl;  On the other hand each of tested nanoparticles solutions Cs-NPs , TiO2NPs ,  were significantly different from  D.W ( P< 0.001) for both.  

Table(3): comparative analysis  between various treatment groups.

When the pulp of the tooth becomes necrotic,  it impossible for immune cells or antibodies to get deep inside the canal due to the loses of blood flow . An acute or chronic case of apical periodontitis can arise  after colonizing of bacteria  and creating a biofilm on the surface of dentine, then eventually can reach to the apex,  a root canal therapy is applied in this case in order  to eradicate and remove infections caused by bacteria. Irrigation is employed during chemo mechanical preparation in order to raise the effectiveness of bacterial removal from root canal ( Elkillany et al., 2022).

 In order to prevent endodontic infection, several  of  root canal irrigants are available. According to Dutner et al.  NaOCl is still the most extensively used  as  irrigant ,because it can   dissolve the organic tissue and its antibacterial activity (Dutner et al., 2012).  

 Despite NaOCl has many advantages but its cytotoxic ( Bosch-Aranda et al. (2012),  , had bad taste and smell, causing bleaching of the clothes and corroding the metallic objects  .It doesn’t have the ability to remove all bacteria,  with the ability to change the characteristics of dentin ,so it’s important to search for save irrigant with strong antibacterial activities ( Mallah, 2021). 

Chlorohexidine is used as irrigation and intracanal medicament. It can not be used as the only irrigant during the endodontic therapy because its unable to dissolve organic tissue (Zehnder, 2006) . Using of both irrigant solutions NaOCl and CHX in order to increase each irrigant's advantages will produce a chemical reaction that will form  a precipitate PAC(Parachloroaniline) which has low antimicrobial activities, also toxicity , staining of tooth structure and  this will prevent root canal filling materials to bond with dentin. So it’s better to avoid mixing them inside root canal ( Echeverri  and Alderete etal., 2015).

Despite the polymicrobial nature root canal infections, E.faecalis has been chosen as an examined organism infection model, because this strain is frequently isolated from apical periodontitis (Sánchez-Sanhueza et al., 2015 ). Furthermore the ability of this strain to survive and multiply under severe conditions  include  high temperature, high PH levels, strongly resistance to antibiotics and starvation also within 72 hours of incubation period E.faecalis have the ability to penetrate deeply  inside TD with the formation of mono species biofilm. This  bacteria can survive and multiply  on its own  without  any depending  on the other bacteria  in endodontic lesions (Mina et al.,2023 ). The antibacterial efficacy of the tested intra canal treatments was  evaluated by using Colony forming units (CFU),  It’s the most easiest and well accepted method , by this technique  the number of bacterial colonies were counted before and after irrigation process.  ( Elkillany et al., 2022). 

 Chitin is the source of chitosan. It's one of the most predominant biopolymers found in nature  . ( Nair, et al.,2018).Various forms of Chitosan involving (solutions, films, and composites)were tested   through  many studies in order to  detect the antimicrobial action of this biopolymer towards a broad extent of microorganisms like bacteria ,fungi and algae  (Kong et al., 2010). Therefore,  to determine the efficacy this material as a final irrigation, the using of it in nanoparticle form is suitable for more  penetration and absorption into the dentinal tubules (Abdelkafy,et al.,2023 and  Razumova etal., 2022)).  On the contrary, The antibacterial and anti biofilm actions towards a variety of bacteria,  G+&G-  were detected by using Tio2 –NPs. Because of their high  ability for oxidizing bacteria through the production of free radicals such as (hydroxyl and superoxide anion radicals) ,this lead to microbial inactivation like Staphylococcus aureus and Escherichia coli  (Dicastillo etal., 2020).  In addition several research have shown that TiO2NPs perform had better antibacterial performance against Gam-positive bacteria.  In Dicamstillo et al. (2019).

All tested treatments reduced the count of E. faecalis bacteria EmAm strain . Cs-NPs (2.5 mg\ml )solution was more effective than TiO2NPs(650µg\ml) solution. Similar to  routine endodontic irrigations, the root canal irrigation process using Cs-NPs and TiO2-NPs provided valuable antibacterial activity by removing bacteria in vitro.  According to this study, the strategies used by both tested treatments to clean up root canal infections were effective.  

1. Ørstavik D.(2004). Virulence Factors of E Nterococcus Faecalis: Crit Rev Oral Biol Med.  .,15(5):308–20.
2. Elkillany,R.Z.M.; El-Ashry,S. and Fakhr,M.(2022).The antimicrobial Efficacy of nanoparticles intracanal medicaments against Enterococcus faecalis biofilm. .Egyptian Dental Journal., 68:1789-1796. DOI : 10.21608/edj.2021.110832.1906
3.   Nair, N.; James,B.; Devadathan,A.; Josey Mathew,M.K.and  Jacob,K.(2018). Comparative Evaluation of Antibiofilm Efficacy of Chitosan Nanoparticle‑ and Zinc Oxide Nanoparticle‑Incorporated Calcium Hydroxide‑Based Sealer: An In vitro Study Contemp Clin Dent.,  9:434-9.
4. Kouidhi B, Zmantar T, Mahdouani K, Hentati H, Bakhrouf A. Antibiotic resistance and adhesion properties of oral Enterococci associated to dental caries.(2011) BMC microbiology.,11(1):1-7.
5. Mallah, S.N. and Al-Naimi, A.M.(2021).  Minimum Inhibitory Concentration of Iron Oxide Nanoparticles with Hydrogen Per Oxide against Endodontic Enterococcus faecalis. Al–Rafidain Dent J., 21(2):158-164.
6. Xia,M.; Zhuo ,N.; Ren,S.; Zhang, H.; Yang,Y.; Lei,L. and Tao Hu.(2022).   Enterococcus faecalis rnc gene modulates its susceptibility to disinfection agents: a novel approach against bioflm. BMCOral health., 22:416  https://doi.org/10.1186/s12903-022-02462-1
7.  Mirhadi H, Abbaszadegan A, Ranjbar MA, Azar MR, Geramizadeh B, Torabi S, Sadat Aleyasin Z, Gholami A. (2015). Antibacterial and toxic efect of hydrogen peroxide combined with diferent concentrations of chlorhexidine in comparison with sodium hypochlorite. J Dent (Shiraz, Iran) .,16(4):349–55.
8. Raura , N.;  Garg , A.;  Arora,A. and   Roma ,M. (2020) Nanoparticle technology and its
9. implications in endodontics: a review.  Biomaterials Research .,  24(21).
10. Yan,D.;  Li,Y.;   Liu,Y.;   Li,N.;   Zhang ,X. and   Yan,C.(2021).Antimicrobial Properties             of Chitosan and Chitosan Derivatives in the Treatment of Enteric Infections. Molecules ., 26: 7136. https://doi.org/10.3390/ molecules26237136
11. Garg, U.; Chauhan, S.; Nagaich, U.; Jain, N.(2019) Current Advances in Chitosan Nanoparticles Based Drug Delivery and Targeting. Adv. Pharm. Bull.   9, 195–204. [CrossRef]
12.   Mo, X.; Cen, J.; Gibson, E.; Wang, R.; Percival, S.L.(2015). An open multicenter comparative randomized clinical study on chitosan. Wound Repair Regen., 23: 518–524. [CrossRef]
13. Jha Z, Behar N, Narayan Sharma S, Chandel G, Sharma D, Pandey MP, et al.(2011). Nanotechnology: Prospects of agricultural advancement. Nano Vision.,1:88-100
14. Dicastillo,C.L.; Correa,M.G.; Martínez,F.B.; Streitt,C and   Galotto,M.G.(2019). Antimicrobial Effect of Titanium Dioxide Nanoparticles DOI: 10.5772/intechopen.90891 FROM THE EDITED VOLUM Antimicrobial Resistance - A One Health PerspectiveEdited by Mihai Mareș, Swee Hua Erin Lim, Kok-Song Lai and Romeo-Teodor Cristina
15. Banu S., Vishnu V., Jamuna K., Kurian G.A. (2014).  Physiochemical Investigation and Biovaluation of TiO2 Nanocrystals Synthesized by Chemical and Green Route, Int. J. Pharm. Pharm. Sci., 6(11): 396-400. 
16.  Sankar ,A; Ramesh.S.; Rajeshkumar,S.and Arun,N. (2023). Anti microbial Activity of Chitosan Nanoparticles with Chlorhexidine- An In vitro Study. J Popul Ther Clin Pharmacol., 30(14):e41–e48
17.  NajemA.H.;  Khudhur,I.M.and. Ali G.M. A.(2023). Inhibitory effectof Titanium dioxide (TiO2) nanoparticles and their synergistic activity with antibiotics in some types of bacteria. Bionaturej., 8 (1 )  .doi.org/10.21931/RB/2023.08.01.34
18.  Sopandani,  P., Iskandar, B.O., Ariwibowo, T.  and Djamil, M.S. (2020). Antibacterial effects of moringa oleifera leaf extract against enterococcus faecalis in vitro. Sci Dent J., 4:16-20.
19. Punjabi,K., Mehta,S., Chavan,R., Chitalia,V., Deogharkar,D. and Deshpande,S.(2018). Efficiency of Biosynthesized Silver and Zinc Reference123Nanoparticles Against Multi-Drug Resistant Pathogens. Front Microbiol., 9: 2207.
20. Keine, K.C., Kuga, M.C., Tormin, F.B., Venção, A.C., Duarte, M.A., Chávez-Andrade, G.M., and Faria, G. (2019). Effect of peracetic acid used as single irrigant on the smear layer, adhesion, and penetrability of AH Plus. Braz Oral Res., 33(2): 57. 
21.  Velozo, C., Silva, S., Almeida, A., Romeiro, K., Vieira, B., Dantas, H., Sousa, F., and De Albuquerque, D.S. (2020). Shaping ability of XP-endo Shaper and ProTaper Next in long oval-shaped canals: a micro-computed tomography study. Int Endod J. 53(7): 998-1006. 
22. Kim, Y., Kim, B.S., Kim, Y.M., Lee, D., and Kim, S.Y. (2019). The penetration ability of calcium silicate root canal sealers into dentinal tubules compared to conventional resin-based sealer: a confocal laser scanning microscopy study. Materials (Basel). 12(3): 531.
23.  Mallah, S.N .(2021). Evaluation of Iron Oxide Nanoparticles as a Root Canal Irrigating Solution (An in vitro Study) MSc Thesis, University of Mosul, Iraq.
24. Roshdy, N.N., Kataia, E.M., and Helmy, N.A. (2018). Assessment of antibacterial activity of 2.5% NaOCl, chitosan nano-particles against Enterococcus faecalis contaminating root canals with and without diode laser irradiation: an in vitro study. Acta Odontol Scand., 77(1): 39-43.
25. Mustafa, E.A., Jawad , I.A. and  Abd Alkadder,A.(2010). Effectiveness of Microwave Sterilization on Soft Lining Material. Al–Rafidain Dent J. ; 10(1): 133-142. 
26. Wayne, W., Daniel, D., Chad, L. (2014). Biostatistics :Basic Concepts and Methodology for the Health Sciences .10^th Amazon Printer .USA.
27.  Elkillany,R.M.,  El-Ashry,S., Sabet, N. and Fakhr, M.(2022)The antimicrobial efficacy of nanoparticles intracanal medicaments against Enterococcus faecalis biofilm. E.D.J., 68 ( 2): 1789-1796. DOI : 10.21608/edj.2021.110832.1906
28. Dutner, J., Mines, A., and Anderson, A. (2012). Irrigation trends among American Association of Endodontists members: a Web-based survey. J Endod. 38(1): 37-40.
29. Bosch-Aranda, M.L., Canalda-Sahli, C., Figueiredo, R., and Gay-Escoda, C. (2012). Complications following an accidental sodium hypochlorite extrusion: A report of two cases. J Clin Exp Dent. 4(3): 194-198.
30. Zehnder, M. (2006). Root canal irrigants. J Endod. 32(5): 389-398.
31.   Echeverri,D and Alderete, D.( 2015). In vitro antibacterial effect of 2% chlorhexidine against Enterococcus faecalis in dentin previously irrigated with 5% sodium hypochlorite. Int. J. Odontostomat., 9 (1):25-29, 2015. 
32.  Sánchez-Sanhueza, G., González-Rocha, G., Dominguez, M., and Bello-Toledo, H. (2015). Enterococcus spp. isolated from root canals with persistent chronic apical periodontitis in a Chilean population. Braz Dent J. 14(3):240–245.
33.  Mina, M.;   Somayeh,T.;   Majid,M.;   Majed1,M.S. and  Maryam ,K. (2023). In vitro reduction in Enterococcus faecalis count following root canal preparation with Neolix and XP shaper rotary files. Saudi Endodontic Journal 13(3):p 236-241,] 
34.  Kong M, Chen XG, Xing K, Park HJ (2010) Antimicrobial properties of chitosan and mode of action: a state of the art review. Int J Food Microbiol 144:51–63
35. Abdelkafy ,H.;  Elsheikh ,H.M. ; Kataia,M.M.; Marzouk,R.M.; Abdeltwab,E.; Atta,A.; Taher,F.A.(2023). Efficacy of using chitosan and chitosan nanoparticles .as final irrigating solutions on smear layer removal and mineral content of intraradicular dentin. Journal of Indian Society of Pedodontics and Preventive Dentistry , 41 ( 2 ):170-177
36.  Razumova S, Brago A, Serebrov D, Barakat H, Kozlova Y, Howijieh A . The application of Nano silver Argitos as a final root canal irrigation for the treatment of pulpitis and apical periodontitis. In vitro study. Nanomaterials (Basel) 2022;12:248
37.  Dicastillo,C.L., Correa, M.G.,   Martínez,F.B.,  Streitt,C. and   Galotto,M.J.(2020). Antimicrobial Effect of Titanium Dioxide Nanoparticles. DOI: 10.5772/intechopen.90891
38. Dicastillo,C.L.; Correa,M.G.; Martínez,F.B.; Streitt,C and   Galotto,M.G.(2019). Antimicrobial Effect of Titanium Dioxide Nanoparticles DOI: 10.5772/intechopen.90891 FROM THE EDITED VOLUM Antimicrobial Resistance - A One Health PerspectiveEdited by Mihai Mareș, Swee Hua Erin Lim, Kok-Song Lai and Romeo-Teodor Cristina