Antimicrobial Photosensitizing Material Based on Conjugated Zn(II) Porphyrins

Abstract

The widespread use of antibiotics has led to a considerable increase in the resistance of microorganisms to these agents. Consequently, it is imminent to establish new strategies to combat pathogens. An alternative involves the development of photoactive polymers that represent an interesting strategy to kill microbes and maintain aseptic surfaces. In this sense, a conjugated polymer (PZnTEP) based on Zn(II) 5,10,15,20-tetrakis-[4-(ethynyl)phenyl]porphyrin (ZnTEP) was obtained by the homocoupling reaction of terminal alkyne groups. PZnTEP exhibits a microporous structure with high surface areas allowing better interaction with bacteria. The UV-visible absorption spectra show the Soret and Q bands of PZnTEP red-shifted by about 18 nm compared to those of the monomer. Also, the conjugate presents the two red emission bands, characteristic of porphyrins. This polymer was able to produce singlet molecular oxygen and superoxide radical anion in the presence of NADH. Photocytotoxic activity sensitized by PZnTEP was investigated in bacterial suspensions. No viable Staphylococcus aureus cells were detected using 0.5 µM PZnTEP and 15 min irradiation. Under these conditions, complete photoinactivation of Escherichia coli was observed in the presence of 100 mM KI. Likewise, no survival was detected for E. coli incubated with 1.0 µM PZnTEP after 30 min irradiation. Furthermore, polylactic acid surfaces coated with PZnTEP were able to kill efficiently these bacteria. This surface can be reused for at least three photoinactivation cycles. Therefore, this conjugated photodynamic polymer is an interesting antimicrobial photoactive material for designing and developing self-sterilizing surfaces.

Effects of Substituents on the Photophysical/Photobiological Properties of Mono-Substituted Corroles

“…The superoxide radical (O 2 •− ) species by NBT reduction assays was used and this approach was carried out at the same conditions stated in the literature, using Nitro Bule Tetrazolium (NBT) and NADH in DMSO solution [ 40 ]. Control experiments were performed in the absence of corroles and all derivatives were irradiated under aerobic conditions with a white-light LED source (fluence rate of 50 mW cm −2 and a total light dosage of 90 J cm −2 ) at a period of 20 min.…”

“…The crystallographic structure for DNA and HSA was obtained from the Protein Data Bank with access code 1BNA and 1N5U, respectively [ 39 , 40 ]. The chemical structure for corroles 2 , 3 and 4 was built and minimized in terms of energy by Density Functional Theory (DFT) calculations under B3LYP potential with basis set 6–31G*, available in the Spartan’18 software (Wavefunction, Inc., Irvine, CA, USA) [ 42 , 43 , 44 ].…”

Diketopyrrolopyrrole Derivatives as Photosensitizing Agents against Staphylococcus aureus

“…Growth conditions of S. aureus strain and statistical analysis are detailed in Supporting Information. Staphylococcus aureus cell suspensions in PBS (2 mL, ~10 8 CFU mL −1 ) were incubated with 2.0 μM DPP in Pyrex culture tubes (13 × 100 mm) for 20 min in the dark at 37°C (31,32). DPPs were added from 1.0 mM stock solutions in DMF.…”

“…•− produces formazan, which can be monitored following the absorption band of the product centered around 560 nm (Figure S2) (22,32). The formation of O 2…”

Poly(oxanorbornene)s bearing triphenylphosphonium and PEGylated zinc(ii) phthalocyanine with boosted photobiological activity and singlet oxygen generation

“…[33][34][35][36][37] This method involves the use of photosensitizers to generate reactive oxygen species (ROS) upon light exposure at an appropriate wavelength and these ROS can cause damage to microbial cells, including oxidation of membrane lipids, nucleic acids, and amino acids, and cross-linking of proteins. 38,39 ZnPc has significant properties such as a relatively high extinction coefficient, excellent visible/near-infrared absorption and the ability to generate ROS to act as a photosensitizer. [39][40][41][42] Here, we have designed and synthesized antibacterial poly(oxanorbornene)s which consist of (i) a TPP moiety and (ii) PEGylated ZnPc.…”