Layer-by-Layer Decorated Nanoscale ZIF-8 with High Curcumin Loading Effectively Inactivates Gram-Negative and Gram-Positive Bacteria

Abstract

Bacteria-mediated infectious diseases have become a health-care challenge globally since the development of antibiotic resistance. Reactive oxygen species produced by photosensitizers have great potential in fighting bacterial infections, especially against Gram-negative bacteria that are hard to kill by regular methods owing to their formidable defensive membrane structures under the premise of avoiding overuse of antibiotics. In this work, a small molecular photosensitizer, curcumin (CCM), was used as a model and encapsulated into zeolitic imidazolate framework-8 (ZIF-8). Then the ZIF-8 loaded with CCM (CCM@ZIF-8) was decorated with biocompatible polymers hyaluronic acid (HA) and chitosan (CS) by the layer-by-layer self-assembly technique to yeild in an antibacterial CCM@ZIF-8@HA@CS nanoparticle with a high local positive charge density and is capable of binding the surface of bacteria by electrostatic interactions. The CCM drug loading capability of the nanoparticle was found to be as high as 10.89%. Upon exposure to blue light (72 J/cm2) for 10 min, the minimum inhibitory concentration and minimum bactericidal concentration of CCM@ZIF-8@HA@CS against Gram-positive bacteria (G(+)) Staphylococcus aureus (S. aureus) and Gram-negative bacteria (G(−)) Escherichia coli (E. coli) were the same, which were as low as 0.625 and 2.5 μg/mL, respectively, showing highly effective antibacterial activities. After treatment with CCM@ZIF-8@HA@CS under blue-light irradiation, the membranes of S. aureus and E. coli folded and cracked. Importantly, the antibacterial agent showed good biocompatibility in the cytotoxicity test using L929 cells and hemolysis test using rabbit blood cells under blue-light irradiation. Therefore, this CCM@ZIF-8@HA@CS nanocomposite is expected to find application in the treatment of superficial traumatic and refractory chronic infections caused by G(+) and G(−).

Encapsulation of Enzymes in Metal–Phenolic Network Capsules for the Trigger of Intracellular Cascade Reactions

“…The synthesis of GOx-encapsulated ZIF-8 (GOx@ZIF-8) NPs was similar to that of ZIF-8 NPs, where GOx was mixed with 2-MIM and 8-arm-PEG-OH before adding Zn-(NO 3 ) 2 . 20,33,36,37 SEM (Figure 3a) and TEM (Figure 3b) images showed that the average diameter of dodecahedral GOx@ZIF-8 NPs coated with TA/Fe 3+ was about 250 nm, which was similar to that of ZIF-8 NPs prepared in the absence of GOx (Figures S1d and S3). Due to the high adhesion of TA to ZIF-8 NPs, MPN shells were easily formed on the surface of GOx@ZIF NPs, which resulted in the increased surface roughness (Figure 3c).…”

Telescopic synthesis and encapsulation of anticancer drugs from Ajuga bracteosa Wall. ex Benth. with zeolitic imidazole framework‐8

“…Intermolecular hydrogen bonds between the phenolic hydroxyl group in ABE and the nitrogen atoms in 2‐methylimidazole cause this encapsulation. [ 39 ] Peak locations in UV–visible spectra are primarily influenced by particle shape and medium dielectric constant, implying polydispersibility of synthesized ABE@ZIF‐8 NPs, whereas the shape of the UV–visible peak determines the morphology of nanoparticles. The broad and asymmetrical surface plasmonic (SPR) bands indicate that the synthesized nanoparticles are anisotropic, while the narrowband indicates that the nanoparticles are spherical‐hexagonal.…”

Bacteria-responsive biopolymer-coated nanoparticles for biofilm penetration and eradication

“…The LbL coating approach applied here has previously been used to develop functionalized nanoparticles primarily for applications in cancer. [59][60][61] LbL has also been applied to NP coatings for antibacterial applications, mainly aimed at eliminating planktonic bacteria or preventing biofilm formation, 62,63 with a limited investigation of biofilm eradication. 64 In this work, we combined the LbL coating of bacteria-responsive polymers with a bacteria-responsive NP core and investigated both biofilm prevention and eradication effects.…”