Abstract: Sonodynamic inactivation (SDI) of pathogens has an important advantage when compared to optical excitation-based protocols due to the deeper penetration of ultrasound (US) excitation in biological media or animal tissue. Sonosensitizers (SS) are compounds or systems that upon US stimulation in the therapeutic window (frequency = 0.8–3 MHz and intensity < 3 W/cm2) can induce damage to vital components of pathogenic microorganisms. Herein, we report the synthesis and application of conjugated polymer nanoparticles (CPNs) as an efficient SS in SDI of methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae and Candida tropicalis. A frequent problem in the design and testing of new SS for SDI is the lack of proper sonoreactor characterization which leads to reproducibility concerns. To address this issue, we performed dosimetry experiments in our setup. This enables the validation of our results by other researchers and facilitates meaningful comparisons with different SDI systems in future studies. On a different note, it is generally accepted that the mechanisms of action underlying SS-mediated SDI involve the production of reactive oxygen species (ROS). In an attempt to establish the nature of the cytotoxic species involved in our CPNs-based SDI protocol, we demonstrated that singlet oxygen (1O2) does not play a major role in the observed sonoinduced killing effect. SDI experiments in planktonic cultures of optimally growing pathogens using CPNs result in a germicide effect on the studied pathogenic microorganisms. The implementation of SDI protocols using CPNs was further tested in mature biofilms of a MRSA resulting in ∼40 % reduction of biomass and ∼70 % reduction of cellular viability. Overall, these results highlight the unique and unexplored capacity of CPNs to act as sonosensitizers opening new possibilities in the design and application of novel inactivation protocols against morbific microbes.
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Example 5 Synthesis of terephthaloyl chloride To 18.6 g (0.11 mole) of <strong>[37091-73-9]2-chloro-1,3-dimethylimidazolinium chloride</strong>, 83 g of toluene was added, and successively 8.31 g (0.05 mole) of terephthalic acid was added. The mixture was reacted at 110 ° C. for 4 hours. The reaction mass was analyzed by gas chromatography. The yield of terephthaloyl chloride was 98percent.
(1R,4S)-cyclohexane-1,4-dimethanol diacetate[ No CAS ]
[ 100-21-0 ]
[ 3236-48-4 ]
[ 3236-47-3 ]
Yield
Reaction Conditions
Operation in experiment
0.12%Chromat.; 0.48%Chromat.; 90.5%Chromat.
With methanol; potassium carbonate; at 20℃; for 17h;
Example 17Preparation of cis-1,4-cyclohexanedimethanol by hydrolysis of its diacetateThe diacetate product from Example 5 (1.08 g, 4.73 mmol) was dissolved in methanol (9.50 mL, 0.50 M). Potassium carbonate (1.44 g, 10.4 mmol) was added all at once. The mixture was stirred for 17 hours at ambient temperature. The volatiles were then removed under reduced pressure. Water (10 mL) was added to the crude mixture. The aqueous phase was extracted three times with 25 mL of ethyl acetate. The organic extracts were combined and dried with sodium sulfate. After filtration, the volatiles were removed under reduced pressure to yield a colorless oil (0.43 g recovered). GC analysis: 90.5percent cis-CHDM, 0.48percent trans-CHDM, 0.12percent terephthalic acid (TPA), and 8.9percent unknown. 1H NMR delta (CDCl3): 3.57 (d, J=6.0 Hz, 4H), 1.71 (m, 2H), 1.61-1.29 (m, 8H).
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