Norbornene-chitosan spray-dried microspheres for peptide conjugation using thiol-ene “photoclick” chemistry

This work was financed by Portuguese funds through FCT/MCTES (Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Inovação) in the framework of the projects 2022.06048.PTDC (i3S), UIDB/50006/2020 (LAQV-REQUIMTE), LA/P/0045/2020 (ALiCE) and UIDB/00511/2020 (LEPABE). P.A. (SFRH/BD/145471/2019) and D.F. (SFRH/ BD/146890/2019) doctoral grants, were financially supported by national (FCT/Norte 2020 Framework) and European Union (ESF – European Social Fund) funds. B.E. acknowledges FCT for the contract based on the “Lei do Emprego Científico” (DL 57/2016). Maria Cristina L. Martins also acknowledges FCT (LA/P/0070/2020), project Bio2Skin Advanced (2021-24):NORTE-01-0247-FEDER-047225; and MOBILIsE Project, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement no. 951723.The action of bioactive peptides, such as antimicrobial peptides (AMP), in the human body is often compromised by limited residence time and stability in the target site. Bioconjugation of peptides to biomaterial surfaces is one of the strategies that may overcome these limitations. Herein, norbornene-chitosan (NorChit) microspheres were engineered to react with thiolated peptides by thiolene “photoclick” chemistry. NorChit microspheres were produced by spray drying and crosslinked with dithiothreitol (DTT) to prevent their solubilization. Microspheres with a diameter of 5 ± 2 µm showed round and smooth morphology with pockets over the surface that could be related with hydrophobic interactions between internal norbornene groups. Thiol-ene bioconjugation carried out using a fluorescent model peptide, showed a yield of 45%, whereas using the peptide but without UV exposure indicated a maximum of peptide adsorption of 30%. Altogether, NorChit microspheres show the potential for carrying bioactive peptides, which may open avenues for AMP activity onto harsh environments in the bod

Preparation of chitosan nanoparticles by spray drying and their antibacterial activity

[[abstract]]Chitosan nanoparticles were prepared from chitosan with different molecular weight by spray drying method. The morphology of chitosan nanoparticles were characterized by SEM and size distribution and zeta potential values were determined. Effect of chitosan solution concentrations, molecular weight of chitosan (MMW, HMW and VHMW) and size of spray dryer nozzles on average size, size distribution and zeta potential values of chitosan nanoparticles were investigated. Moreover, the effect chitosan nanoparticles and chitosan nanoparticles/amoxicillin complex on Staphylococcus aureus was also tested. The results showed that the average size of chitosan nanoparticles were in the range of 95.5 to 395 nm and zeta potential values of 39.3 to 45.7 mV depended on concentration and molecular weight of chitosan. The lower concentration and molecular weight of chitosan were used, the smaller size of chitosan nanoparticles and the higher zeta potential values were obtained. The testing for antibacterial activity against S. aureus indicated that chitosan nanoparticles strongly inhibited the growth of bacteria with the minimum inhibitory concentration (MIC) of 20µg/mL, which were lower than that of chitosan solution and amoxicillin. The antibacterial capacity of chitosan nanoparticles also depended on size, zeta potential values and molecular weight of chitosan. Complex of chitosan nanoparticles/amoxicillin could improve antibacterial activity of amoxicillin.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子