Abstract
Covalent conjugation of (bis)phosphonate group-containing molecules, sodium Alendronate (Aln) and 3-AminoropylPhosphoric Acid (ApA), to Cellulose nanocrystals (CNCs) was performed via oxidation/Shiff-base reaction. Further fluorescent labelling with Rhodamine B Iso ThioCyanate (RBITC) was performed to follow CNCs interaction and potential internalization with/in human osteoblasts by confocal microscopy. Complementary analyses were applied to identify the conjugation (Atenuated Total Reflectance–Fourier Transform Infrared and UV–VIS spectroscopies), physico-chemical (Dynamic Light Scattering and Nanoparticle Tracking Analysis) and morphological (Transmission Electron Microscopy) features of native and ApA/Aln-modified CNCs in physiologically relevant environments (Phosphate Buffer Saline, Advanced Dulbecco’s Modified Eagle Medium). While conjugation did not affect the CNCs` size, the RBITC-labelling promotes their aggregation. Faster (1 h vs. 2 h) uptake by osteoblasts of RBITC-CNCoxAln, compared to RBITC-CNCoxApA, and no-internalization (in 24 h) of native RBITTC-CNC, indicate a higher affinity of Aln-modified CNCs to the cells, while all CNCs (in 0.25–0.06 wt%) promote the cell growth. Aln/Apa-modified CNCs shows high potential in drug-delivery for bone therapies, and theranostics.
Highlights
Various nanoparticles (NPs) have been considered increasingly in the last decade for their usage as biosensors, imaging agents and drug delivery vehicles (Mahmoudi et al 2012)
The cellulose nanocrystals (CNCs)’ modification with Aln and aminopropylphosphonic acid (ApA) molecules [presented in Scheme 1, according to the literature (Dash et al 2012)] was carried out using a Shiff-base coupling reaction betweenphosphonate amine and cellulose (CNC) aldehyde groups which are formed during the oxidation process
Further RBITC-labelling of both native and ApA or Aln modified CNCs was performed according to the well-known nucleophilic addition mechanism of cellulose hydroxyls with RBITC’ isothiocyanate group (National Institute of Industrial Research (India) 2006) in a highly alkaline (NaOH) medium, forming a stable covalent bond (Vieira Ferreira et al 1998)
Summary
Various nanoparticles (NPs) have been considered increasingly in the last decade for their usage as biosensors, imaging agents and drug delivery vehicles (Mahmoudi et al 2012). Most of these applications require successful internalization of NPs into the targeted cells, deep understanding of the interactions between NP and biomolecules/cell membrane is an important prerequisite for designing and engineering NPs with intentionally enhanced or suppressed cellular uptake. Internalization of NPs into cells can initialize the well-tolerated, non-cytotoxic, and even therapeutic (Panariti et al 2012; Tsai et al 2013) or cytotoxic (i.e. cell dead or decreased cellular activity) effect (Huerta-Garcıa et al 2015). The anatase titanium dioxide (the metallic implant debris-originated) was internalized readily by primary osteoblasts, and affected the adhesion strength, migration and proliferation of the cells negatively (Ribeiro et al 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
