Reproducible and controlled peptide functionalization of polymeric nanoparticles

Abstract

Polymeric nanoparticles containing multiple amines and carboxylates have been frequently used in drug delivery research. Reproducible and controlled conjugation among these multifunctional biomaterials is necessary to achieve efficient drug delivery platforms. However, multiple functional groups increase the risk of unintended intramolecular/intermolecular reactions during conjugation. Herein, conjugation approaches and possible undesired reactions between multi-amine functionalized peptides, multi-carboxylate functionalized polymers, and anhydride-containing polymers [Poly(styrene-alt-maleic anhydride)-b-poly(styrene)] were investigated under different conjugation strategies (carbodiimide chemistry, anhydride ring-opening via nucleophilic addition elimination). Muti-amine peptides led to extensive crosslinking between polymers regardless of the conjugation chemistry. Results also indicate that conventional peptide quantification methods (i.e., o-phthalaldehyde assay, bicinchoninic acid assay) are unreliable. Gel permeation chromatography (GPC) provided more accurate qualitative and quantitative evidence for intermolecular crosslinking. Crosslinking densities were correlated with higher feed ratios of multifunctional peptides and carbodiimide coupling reagents. Selectively protected peptides (Lys-Alloc) exhibited no crosslinking and yielded peptide-polymer conjugates with controlled dispersity and molecular weight. Furthermore, anhydride ring-opening (ARO) nucleophilic addition elimination was successfully introduced as a facile yet robust peptide conjugation approach for cyclic anhydride-containing polymers.

Impact of Nanoparticle Physicochemical Properties on Protein Corona and Macrophage Polarization

“…Amphiphilic diblock copolymers of poly­(styrene- alt -maleic anhydride)- b -poly­(styrene) (PSMA- b -PS) were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization, as described previously. ,,,, PSMA- b -PS copolymers were then self-assembled into NPs via solvent exchange with a hydrophobic core (PS) and a hydrophilic shell (PSMA). ,,,, DMAEMA NPs, consisting of a pH-responsive core and cationic corona, were self-assembled from poly­(dimethylmethacrylate)- b -poly­(dimethylaminoethyl methacrylate- co -butyl methacrylate- co -propylacrylic acid) or p­(DMAEMA)- b -p­(DMAEMA- co -BMA-PAA) also synthesized via RAFT, as described previously. , For PEG-PS copolymers, PS-COOH was first synthesized via RAFT, followed by carbodiimide chemistry for conjugation of PEG to PS-COOH in an organic solvent. , Polymer molecular weights were determined with gel permeation chromatography (GPC). NP size and surface charge were measured using DLS (Malvern Instruments, Worcestershire, UK), where the polymer concentration is 0.1 mg/mL.…”

Abstracts from the 50th International Musculoskeletal Biology Workshop, July 22 – 27, 2023, Midway, Utah

“…These extremely bright nanoparticles can be functionalized in many ways and can act as a targeted probe for integrins via surface RGD motifs (RGD-C'Dots). In previous work we validated the use of non-targeted and integrin-targeted C'Dots as novel in vivo osteocyte and integrin imaging tools 7 . Here we continue that work, exploring dynamin related integrin dynamics as well as using C'Dots to visualize dendritic processes and subcellular localization within the lacuno-canalicular network (LCN) in vivo.…”

“…For these studies, tamoxifen was given at 7-8 weeks of age to induce Cre-Lox recombination. We also utilized mice heterozygous for a global Hoxa13 null allele (Hoxa13 +/-) and compared them to wild type (WT) littermates [7]. Regenerative digits were established by resecting 25% of the P3 length at 10-12 weeks of age.…”

“…In depressurized and slowly slid (~1mm/s) SCA contacts, equilibrium friction coefficients of OA-like cartilage (µk=0.2-0.3) are 2X higher than healthy tissue. 7 However, the clinical relevance of SCA-based findings is unclear given that cartilage operates at higher average sliding speeds (30-80mm/s) and markedly lower frictions (µk<0.005) in vivo. 8 Recent studies employing the convergent SCA (cSCA) reveal that modest sliding speeds (>30mm/s) facilitate interstitial fluid recovery and sustain near-physiological friction (µk≤0.02 in saline and µk≤0.005 in synovial fluid (SF)) via tribological rehydration.…”

“…8 Recent studies employing the convergent SCA (cSCA) reveal that modest sliding speeds (>30mm/s) facilitate interstitial fluid recovery and sustain near-physiological friction (µk≤0.02 in saline and µk≤0.005 in synovial fluid (SF)) via tribological rehydration. 7 Critically, cSCA tribological behaviors are largely insensitive to mechanical properties in healthy 8-9 and OA-like cartilage. 10 Here, we examined whether CXL-mediated stiffening alters cartilage lubrication under biofidelic sliding conditions in the cSCA.…”