Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5936_Библиотеки_им_академика_М_И_Перельмана
.pdf
268 Golnar Bayatani et al.
https://t.me/medicina_free
Figure 12.5: FTIR spectra study of CPA, CPA-CDs, and CPA-CDs/NONOate [18].
Making a wound is one of the valuable experiments done in this study. Male SD
rats (average body weight was 200 g) were divided into three groups, and two wounds
in each rat’s back were created two days before the experiment started. The size of
injuries was about 10 nm. 100 μLofP. aeruginosa was injected into wounds, and
group one treated with CPA-CDs, group two was treated with CPA-CDs/NONOate, and
group three was not treated. Imaging of the wounds was done for ten days. And result
suggests that CPA-CDs/NONOate play an influential role in fighting bacteria and
wound healing (Figure 12.6).
Figure 12.6: Effect of CPA-CDs/NONOate in wound healing [18].
Good biocompatibility is one of the essential properties of ea ch therapeutic agent;
therefore, biocompatibility of CPA-CDs/NONOate must be measured. For this purpose,
rat’s body weight was measured, and no significant body weight change was reported.
Furthermore, histological studies were done on critical organs like the heart, liver,
kidney, lung, and spleen. The result revealed that treatment with CPA-CDs/NONOate
and CPA-CDs does not have toxicity and side effects on other organs [18].
Chapter 12 Carbon dots in antibiosis: disinfection and sterilization 269
https://t.me/medicina_free
12.2.4 CDs-C12
Jing Yang et al. studied about CDs-C12, and it was published in ACS’s Applied Materials
&Interfacesjournal. CDs-C
their antibacterial effect with their precure that were CDs(synthesized by a combination of AEEA and glycerol) and BS-12 (which were made with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide.
N-hydroxysulfosuccinimide (Sulfo-NHS) in 2-(N-morph olino) ethan esulfonic acid
(MES) buffer solution). The result suggest that CDs-C
antibiosis. We explain this excellent article below briefly.
For characterized many nanostructures, some analyses have been done. One of
them is TEM image. This method was used in this study, and their consequences reveal that the middling size s CDs is about 2.7 nm, and the average size of CDs-C
bigger, approximately 4 nm. Moreover, the hydrodynamic diameter of CDs-C
larger than CDs[19].
Furthermore, to achieve more detail about the structure of CDs-C
FTIR spectra were used. This method suggests that signals in the range of ~ 1010–
−1
1160 cm
C
12
between CDs-C
attributed to Si − O and C − O stretching vibration were joint between CDs-
and CDs. Moreover, three signals (1467 cm−1, 2922 cm−1,2852cm−1)weresimilar
and BS-12. UV–vis show that BS-12 does not have an absorption pick;
12
CDs have two wide picks at 280 and 340 nm, and CDs-C
This new pick may be attributed to changes in the structure’s functional group surface. One important future of many nanostructures used for antibacterial is their stability in different aqueous solutions [19]. For this purpose, CDs-C
PBS solution, normal saline, deionized water, and LB medium. Results suggest CDs-C12
has a stable structure and is valid for biomedical application, and this theory arose
that excellent water-dispersibility for abundant hydroxyl group on their surface [19].
Some tests had to be done to confirm that CDs-C12 is a practical antimicrobial
agent. one of them was measuring optical density (OD), and for this purpose, S. aureus
was used. The result revealed that at 30 ug/mL of CDs-C12 (at a defin ed time), the
growth of bacteria was wholly inhibited, whereas the same concentration of CDs and
BS-12 did not inhibit bacterial growth. Furthermore, a cell counting kit-8 (CCK-8) assay
was used and suggested that CDs-C12 play a role in decreasing S. aureus viability
while neither BS12 nor CDs cannot decrease S. aureus viability [19].
Four plates were selected for the CFU counting method, and S. aureus was grown
on them, and one-to-one was treated with BS-12(,10 μg/mL) CDs, CDs-C12, and one for
the control group not treated. And results suggest that the number of colonies treated
with CDs-C12 significantly decreased (Figure 12.7) [19].
In another experiment in vitro, mice were used as animal models and made a
wound on their back in this study. After that, they were divided into to two groups
[19], group one was treated with white PBS solution, and group two was treated
with CDs-CD12 result after quantification revealed that in group one, bacteria i n the
[19] they synthesized CDs-C12 and experimented with
12
is practical in antibacterial and
12
, CDs and BS-12
12
has a new pick at 510 nm.
12
was scattered in
12
12
12
is
is
270 Golnar Bayatani et al.
https://t.me/medicina_free
Figure 12.7: CFU counting method after treated with CDs, CD-C12, BS12 [19].
infectious tissue showed 2.2 × 108 CFU/g, and in group two, the bacterial burden was
2.8 × 106 CFU/g.(Figure 12.8)
Figure 12.8: The bacterial burden in the wound of mice [19].
For the experiment on gram-negative bacteria, E. coli was used, and some tests, like the
CCK-8 assay, were done. The result revealed that BS-12 and CDs do not have an antibacterial effect on Gram-negative bacteria. Additionally, CDs-C12 at a concentration of
200 μg/mL does not show significantly antibacterial properties. Moreover, optical density studies confirm that CDs-C12 can inhibit Gram-positive bacteria more than Gramnegative bacteria [19].
12.2.5 Nitrogen-doped carbon quantum dots
Antibiotic resistance has been important and perilous subject in recent years; the possibility exists that if antibiotic resistance expands and does not invent other fighting
methods against bacteria, perhaps come back to the time before antibiotics. Accordingly, Chengfei Zhao et al. studied nitrogen-doped carbon quantum dots and broadcasted it in Biointerfaces journal. In this study, for synthesized nitrogen-doped carbon
quantum dots (NCQDs), glucose and diethylenetriamine were used as a precursor and
made by the heat fusion method. TEM microscopy suggests that the average diameter
Chapter 12 Carbon dots in antibiosis: disinfection and sterilization 271
https://t.me/medicina_free
of NCQDs was approximately 5 nm. FTIR spectrum analysis of NCQDs is summarized
in the Table 12.2 [20].
Table 12.2: FTIR spectrum of nitrogen-doped carbon quantum dots (NCQDs) (peak unit is cm−1) [20].
Bond −OH/NH CH C = C −CH C − NN− H
Peak , , , , , ,
To measure the antibacterial activity of NCQDs, some experiments were done. The
plate-diffusion method is one of them, with eight agar plates, including:
1. S. aureus (ATCC6538)
2. S. aureus (ATCC43300)
3. S. epidermidis
4. MRSA
5. E. coli
6. Salmonella paratyphi-β (S. paratyphi-β)
7. Pseudomonas aeruginosa (P. aeruginosa)
8. Enterococcus faecalis (E. faecalis)
after that, three disks were created on each plate containing NCQDs, DETA, and glucose. DETA and glucose were used as control and inhabitation zone measured in each
plate, S. aureus (ATCC6538), S. aureus (ATCC43300), S. epidermidis, and MRSA. The inhibition zones on the agar plates incubating S. aureus (ATCC43300) were approximately 15.5 mm, and the result for S. aureus (ATCC6538), S. epiderm idis,andMRSA
was about 14.5 mm. The result of the plate-diffusion method suggest that NCQDs have
more antibacterial effect on Gram-positive bacteria, especially Staphylococcus more
than others [20].
Another experiment was done to confirm the antibacterial activity of NCQDs; in
this experiment, the negative control groups MRSA and E. coli were treated with normal saline. In another group, MRSA and E. coli were treated with NCQDs. In the third
group, S. aureus (ATCC6538) was treated with NCQDs and TEM imaging was done on
bacteria in each group [20]. Results show that no cell death or damage was evident in
group one. In group two, rupture and loss of integrity were observed in MRSA; on the
other hand, the morphology of E. coli in groups one and two did not differ. It can be
considered that NCQD does not have an antibacterial effect against E. coli, and in the
third group, the cell structure of S. aureus collapsed [20].
A wound formed in the back of the SD rats was excised and infected with MRSA
in this article, which also measured the therapeutic effect NCQDs. Wounds were
treated with NCQDs after four days. As a control group, other mice received standard
saline treatment, and in a third group, treatment with white lasted for seven days. In
the group that received standard saline treatmen t, the wound surface still had pus
and exudates. In the group that received treatment with NCQD and vancomycin, the
272 Golnar Bayatani et al.
https://t.me/medicina_free
size of the infected wounds shrank dramatically. The wound areas were in the normal
saline group NCQD and vancomycin groups after receiving treatment for two weeks.
In other words, both therapy groups had essentially healed their wounds [20].
Furthermore, the cytotox icity of NCQDs on mammalian cells measured for this
purpose HeLa and PANC-1 were used, cell viability was measured, and results were
revealed when the concentration of NCQDs was 0.128 mg/mL. The viabilities of HeLa
and PANC-1 cells were more than 80% [20].
12.2.6 Levofloxacin-based carbon dots
The grand structure was introduced by Li-Na Wu and published in an article in Carbon journal. Levofloxacin-based carbon dots (LCDs) synthesized to fight with antibi-
otic resistance. Levofloxacin is soluble in water. LCDs were m ade by wet-heating
method mainly through bottom-up synthesis methods. TEM study suggests the size of
LCDs was about 7.00 ± 0.25 nm. At pH 7.4, the zeta potential of LCDs was + 28.00 ±
0.50 mV. Spectroscopy studies reveal absorption peaks at 240 nm, 293 nm, and 340 nm
for levofloxacin. The absorption peak in LCDs was lifted from 240 nm to 260 nm and
293 nm to 276 nm. FTIR analyses reveal more information about the structure and
charm of LCDs. For instance, peaks of C = O stretching vibration were at 1698.57 cm
−
3500–2500 cm
1 were for COOH. 3431.78 cm−1was for −OH (Table 12.3) [21].
The disk diffusion test was done to measure in vitro antibacterial activity of LCDs.
Bacterial used were S. aureus, S. epidermidis, E. faecalis, L. monocytogenes, MRSA, E. coli,
P. aeruginosa,andS. marcescens. four disks in each plate were created that contained:
10 mg of insoluble levofloxacin, soluble levofloxacin hydrochloride solution, LCDs solution from levofloxacin hydrochloride, and LCDs solution from levofloxacin. Results suggest that insoluble levofloxacin in the insoluble state had no antibacterial effect. And the
antibacterial ability of LCDs was higher than levofloxacin. At 0.125 mg/mL of LCDs, the
MIC of S. aureus, E. coli, and S. marcescens was more minor than others; at 0.5 mg/mL of
LCDs, the MIC of S. epidermidis, E. faecalis,andL. monocytogenes was larger.
Another experiment to measure the antibacterial effect of LCDs was TEM microscopy studies. S. aureus, E. coli,andMRSA was incubated with LCDs and Levo-HCL and
control group. According to the findings, bacteria that were incubated with levofloxacin
hydrochloride still had fully developed cell membranes. However, the bacterial walls
and membranes were torn, allowing for the leakage of intracellular materials [21].
−1
.
Cow milk-derived carbon dots
This study is done by Yu Tang et al. and published in applied Surface Science journal.
Hydrothermal treatment of cow milk is used to arrange cow milk-derived carbon dots
(CMCDs) then this prepared CMCDs get extracted by ethyl acetate for obtaining
Chapter 12 Carbon dots in antibiosis: disinfection and sterilization 273
https://t.me/medicina_free
amphiphilic CMCDs (ACMCDs). By using ACMCDs as reducing agent and template, we
can make ACMCDs-supported silver nanoparticles (ACMCD-Ag nanocomposites) which
have a great biocidal impact on Gram-positive (Staphylococcus aureus) and Gram-negative (E. coli) bacteria. After that, we can prepare new ACMCD Ag/polymethylmethacrylate (PMMA) nanocomposite antibacterial film by solvent ca sting method. Due to
its excellent antibacterial properties, light absorption and flexibility, nanocomposite
antibacterial film has a high potential in applications[22]. The FTIR spectrum of
CMCDs is shown in Table 12.1 [23]. The UV–vis spectrum of the this CMCDs shows a
broad absorption band which are centred at 274 nm [24]. The size distribution of this
CMCDs are represented in Figure 12.9, which showed that the CMCDs have good dispersion and narrow size distribution (average diameter = 1–5 nm) [22].
Table 12.3: The FTIR spectrum of CMCDs [22].
Peaks (cm
Bond O–H and N–HC–HC=ON–HC=C
Figure 12.9: distribution of the CMCD particle size [22].
−
) – ,
The minimum inhibitory concentration (MIC) test and Kirby-Bauer disk diffusion
method were used to confirm the antibacterial activity of ACMCD-Ag against Gramnegative (E. coli) and Gram-positive (S. aureus) bacteria. AgNO
served as a model sub-
3
stance for activity comparison. For both E. coli and S. aureus strains, the disks with
ACMCD-Ag were surrounded by an inhibition zone with a wider width than those
with AgNO
. After 24-hour incubation period, AgNO3’s MIC was higher than that of
3
274 Golnar Bayatani et al.
https://t.me/medicina_free
ACMCD-Ag (Table 12.4). So, at the same Ag concentration, ACMCD-Ag possesses better
antibacterial properties than AgNO3 [22].
Table 12.4: Lists of the minimum inhibitory concentrations
of AgNO3 and ACMCD-Ag nanocomposite for two bacteria
−1
, calculated by Ag) [22].
(μgmL
Culture Strain no MIC
S. aureus ATTC ,
E. coli ATCC ,
a
MIC
b
Furthermore, compared to E. coli, the nanocomposite showed higher biocidal activity
against the Gram-positive bacteria S. aureus. The cell shape may be the reason for the
ACMCD-enhanced Ag’s antibacterial effectiveness against Gram-positive bacteria. The
loose cell wall of Gram-positive S. aureus makes it vulnerable to assault by nanoparticles. As a result, DNA denaturation in S. aureus occurred more quickly than in E. coli
as a result of the liberated silver nanoparticles’ ability to enter the cell wall and bind
to DNA [25].
The thin film UV–vis absorption spectra as a function of nanocomposite doping
levels are shown in Figure 12.10. The thin film attachment method was employed to
assess the antibacterial property after one day of incubation, and the results revealed
that the percent decrease of bacteria was near to 100% against both S. aureus and E.
coli. Consequently, the ACMCD-Ag/PMMA thin film has a good antimicrobial efficiency
regardless of Gram classes [22].
Figure 12.10: The UV–vis absorption spectra of PMMA composite films
with various ACMCD-Ag nanocomposite doping levels [22].
Chapter 12 Carbon dots in antibiosis: disinfection and sterilization 275
https://t.me/medicina_free
Photodynamic effects were produced by carbon dots functionalized with ampicillin
when exposed to visible light
Rabah Boukherroub et al. conducted this work, which was published in the journal of
Colloids and Surfaces B: Biointerfaces. In this study, we demonstrate a novel strategy
for antibacterial therapy using amine-terminated carbon dots (CDs-NH
)functional-
2
ized with AMP. The amine-functionalized CDs are utilized to transport and immobilize
AMP as well as operate as a visible light-activated antibacterial agent (CDs-AMP). Furthermore, AMP immobilized on the CDs-NH
surface is more stable in solution than
2
free AMP. The AMP conjugated CDs platform maintains the Theranostic properties of
CDs-NH
while combining them with the antibacterial properties of AMP. As a result,
2
E. coli growth is effectively inhibited by the immobilized AMP on CDs-NH2 surface
and the generation of reactive oxygen species under visible light irradiation [26].
While AMP absorbs light below 260 nm, CDs-NH
has three bands in its UV–vis absorp-
2
tion spectra at 237, 342, and 450 nm [27]. Table 12.1 displays the FTIR spectrum of the
CDs-AMP conjugate (Table 12.5) [26].
Table 12.5: The FTIR spectrum of CDs-AMP conjugate[26].
Peaks (cm
Bond O-H Aromatic C–H Aliphatic C–H C = O C-C C-O C-S
−
) – – – –
Results of cytotoxicity and cellular absorption of mammalian (HeLa) cells unequivocally demonstrate the suitability of CDs-NH2 and CDs-AMP for biomedical applications
[26].
The E. coli K12-MG 1655 strain was used to test the bactericidal effects of the CDs-
and CDs-AMP conjugates with and without illumination by visible light. To count
NH
2
the number of viable cells, we used plating. To measure cell proliferation, we used a
fluorescence-based cell dead/live assay and optical density at 600 nm. Red fluorescence indicates dead cells, while green fluorescence indicates living cells. Contrary to
CDs-NH
and CDs-AMP, which demonstrated a strong bactericidal effect on E. coli, the
2
amine-functionalized CDs were not dangerous [26].
Additionally, we have looked at the capacity of CDs-NH2 and CDs-AMP to produce
singlet oxygen (1O
using antimicrobial pa rticles (PPDT). According to the findings, 1O
) when illuminated with visible light for photodynamic therapy
2
levels rose with
2
exposure time and visible light lamp intensity. It was feasible to assess how successfully these chemicals damage bacterial cells by exposing E. coli K12-MG 1655 to CDsNH2 and CDs-AMP at various concentrations (for 10 or 20 min at 0.3 W). As shown in
Figure 12.11, at a concentration of 400 g mL-1, CDs-NH
was able to reduce E. coli sur-
2
vival, indicating that the concentration of CDs-NH2 impacts the photodynamic bacterial killing impact. E. coli cells after 20 min of radiation by 4 log10. This is in line with
how much singlet oxygen CDs-NH
produces [26].
2
276 Golnar Bayatani et al.
https://t.me/medicina_free
Additionally, exposing CDs-AMP to visible light increased the conjugate’s bactericidal activity (Figure 12.11B). The significant improvement in the bactericidal activity
of CDs-AMP may be due to the production of ROS species by the CDs-NH2, including
1
singlet oxygen (
O2). The CDs-AMP conjugate still has some of the CDs-NH2’s natural
Theranostic abilities. It follows that the CDs-AMP combination can be used as a multifunctional nanoplatform based on the combined therapeutic killing of antibiotics
with visible light-generated photodynamic effects [26].
Figure 12.11: (A) Shows the photodynamic efficacy of CDs-NH2 for E. coli K12-MG 1655 inactivation after
illumination at 0.3 W for 10 and 20 min. (B) Role of CDs-NH2 and CDs-AMP concentrate on effectiveness
of E. coli treatment without (solid lines) and with (dash lines) illumination by visible light (20 min, 0.3 W).
The standard deviation of three separate experiments is shown by the error bars [26].
Titanium-based carbon quantum dots@hematite nanostructures
Omran Moradlou and colleagues conducted this investigation, which was then published in Journal of Photochemistry and Photobiology A: Chemistry. Under both dark
and light circumstances, thin films of nanostructured hematite (-Fe2O3) and hematite
combined with carbon quantum dots (CQDs@-Fe2O3) were tested for their ability to
inhibit the growth of Gram-positive (S. aureus) and Gram-negative (E. coli)bacteria
[28]. Samples of Ti/-Fe2O3 and Ti/CQD@-Fe2O3 were created using the hydrothermal
technique[29]. With the use of FE-SEM and HRTEM, the surface morpho logy of the
samples was examined[28].
In order to test the antibacterial properties of the Ti/-Fe2O3 and Ti/CQD@-Fe2O3
samples against Gram-positive S. aureus (ATCC 6538, PTCC 1112) and Gram-negative E.
coli (ATCC 25,922, PTCC 1399) bacteria in both dark and light environments, an antibacterial drop test was used [28].
Dark conditions
https://t.me/medicina_free
Chapter 12 Carbon dots in antibiosis: disinfection and sterilization 277
The bactericidal activity of Ti/-Fe
Table 12.1. By comparison, the Ti/-Fe
against E. coli was minimal (10%), as shown in
2O3
mixture inactivate 65% of the S. aureus bacteria.
2O3
About 20% of E. coli and 70% of S. aureus bacteria were inactivated by the Ti/CQD@-
when left in the dark condition. In fact, both the Ti/-Fe2O3and Ti/CQD@-Fe2O
Fe
2O3
samples have a higher propensity to inactivate S. aureus in comparison to E. coli.Itsuggests that bacterial strains of S. aureus are more suscept ible to antibacterial metal
oxide compounds than are bacterial strains of E. coli. The existence of an additional
outer membrane layer in Gram-negative bacteria is mostly to blame for the enhanced
resistance of Gram-negative strains to hematite-based compounds and the samples’ improved antibacterial effectiveness against Gram-positive bacterial strains [30].
The illumination conditions
It is anticipated that under light irradiation, more ROS would be produced and, as a
result, a lower percentage of the bacteria would survive. According to the findings
(Table 12.6), Ti/-Fe
inactivates E. coli 50% more quickly under light illumination
2O3
than it does in the dark. Additionally, photoinactivation of the E. coli population with
Ti/CQD@-Fe
sample is greater in the presence of light than it is in the absence of
2O3
light (Table 12.6). Under conditions of light irradiation, ROS can develop and enter bacterial cell membranes and harm them. The FE-SEM pictures suggest that S. aureus bacteria
are easily distorted when by antibacterial chemicals, and after their membrane is damaged, the contents of the cell leak outside. However, it may be said that the E. coli bacteria
strain’s cell walls are more resistant to oxidative species.Actuality,Gram-negativebacteria have an additional outer membrane that frequently provides chemical resistance [28].
3
Table 12.6: Antibacterial activity data of Ti/-Fe2O3 and Ti/CQD@-Fe2O3 samples under
circumstances of darkness and visible light [28].
Condition Microorganism Initial concentration
Dark E. coli . ×
S. aureus . ×
Visible light
E. coli . ×
illumination
S. aureus . ×
(CFU/mL)
. ×
. ×
. ×
. ×
Sample Antibacterial
activity (%)
Ti/α-FeO
Ti/CQD@α-FeO
Ti/α-FeO
Ti/CQD@α-FeO
Ti/α-FeO
Ti/CQD@α-FeO
Ti/α-FeO
Ti/CQD@α-FeO
Соседние файлы в папке Библиотека им академика М.И. Перельмана