Poly(N-acryloyl ciprofloxacin-co-acrylic acid) grafted magnetite nanoparticles for microbial decontamination of collagen solution: have we conquered the problem of antimicrobial residues?

Abstract

Widespread concern over antimicrobial toxicity and resistance development necessitates the thorough recovery of antimicrobial compounds from decontaminated collagen. Herein, ciprofloxacin molecules were acryloylated by reaction of the secondary amine in 7-piperazinyl substituent with acryloyl chloride, and then covalently immobilized, for the first time, on the vinyl-functionalized Fe 3 O 4 nanoparticle surface via graft copolymerization with acrylic acid, in an effort to design a magnetically-recoverable nanocomposite potentially applicable for microbial decontamination of collagen solution. Unlike previous magnetite-supported antimicrobials invariably involving the release of antimicrobially-active component, these immobilized ciprofloxacin moieties proved non-leachable, in whole or in part, from the magnetite core, exerting antimicrobial activity as free ciprofloxacin, and thus could be thoroughly recovered from decontaminated collagen solution under magnetic fields. Also, it was found that the unique triple-helical conformation and, hence, bioactive properties of tropocollagens remained intact after decontamination using such recoverable antimicrobials. This proof-of-principle study aims to shed light on a long-standing dilemma in the collagen community: how to decontaminate collagen using antimicrobial compounds without being subject to antimicrobial residues? † Electronic supplementary information (ESI) available: Fourier transform infrared (FTIR), 1 H and 13 C Nuclear Magnetic Resonance (NMR) spectroscopy, and Energy Dispersive X-ray (EDX) spectra. See

Switchable Control of Antibiotic Activity: A Shape-Shifting “Tail” Strategy

“…After that, the precipitate was dried, redissolved in anhydrous DCM, and refined by silica gel chromatography (DCM-methanol 2%) to obtain the final product (1.38 g, 78% yield). Chemical structure of the product was confirmed by FT-IR, 1 H and 13 C NMR spectroscopies, which could be found in our previous publications. , …”

“…To this end, ciprofloxacin was acryloylated by site-specific reaction of the secondary amine in the 7-piperazinyl substitute with acryloyl chloride. Our recent investigations , showed that the resultant N -acryloyl ciprofloxacin was still bioactive, because the 3-carboxyl, 4-keto, and quinolone pharmacophore, all essential for hydrogen-bonding with DNA gyrase and topoisomerase IV to elicit inhibitory action on in vivo DNA synthesis, remained intact. By consecutive RAFT polymerization, the PNIPAM “tail” was attached to the antibiotic “head” via noncleavable linkages, preventing artifacts by undesirable release of small-molecule antibiotics.…”

“…N -Acryloyl ciprofloxacin was synthesized according to our recently disclosed method (Scheme ). , In brief, ciprofloxacin (1.52 g, 4.59 mmol) and Et 3 N (0.71 g, 6.89 mmol) were dissolved in 30 mL anhydrous DCM in a round-bottomed flask. The mixture was cooled at 0 °C by using an ice bath, and purged with dry nitrogen for 30 min before a solution of acryloyl chloride (0.66 g, 7.12 mmol) in anhydrous DCM (10 mL) was added dropwise.…”

Interaction of Carboxyalkylated Cellulose Nanocrystals and Antibiotics

“…In detail, the DOX-CNC spectra contain a peak at 400 eV raised from the nitrogen atom of DOX, while the spectrum for CIP-PCNC shows peaks at the binding energy of 687.7 and 400 eV, which are related to the fluorine and nitrogen of CIP on the PCNC (Figure S4). Elevated peaks at 164.2 and 400 eV in the SMX-PCNC spectrum are also ascribed to sulfur and nitrogen contents of SMX, revealing its adsorption on PCNC.…”

Collagen modified with epoxidized safrole for improving antibacterial activity

“…The CD spectrum of unordered collagen is usually characterized by a single band below 200 nm, whereas triple-helical structure usually presents one negative band at 223 nm, along with one positive band at 197 nm. 19,20 It has been well established that the absolute ratio value of molar ellipticity at 220 nm over molar ellipticity around 195-197 nm (Rpn) can be used to characterize the integrity of triple-helical conformation of collagen in solution. As shown in Fig.…”