Antibody-like Biorecognition Sites for Proteins from Surface Imprinting on Nanoparticles

Abstract

Natural antibodies are used widely for important applications such as biomedical analysis, cancer therapy, and directed drug delivery, but they are expensive and may have limited stability. This study describes synthesis of antibody-like binding sites by molecular imprinting on silica nanoparticles (SiNP) using a combination of four organosilane monomers with amino acid-like side chains providing hydrophobic, hydrophilic, and H-bonding interactions with target proteins. This approach provided artificial antibody (AA) nanoparticles with good selectivity and specificity to binding domains on target proteins in a relatively low-cost synthesis. The AAs were made by polymer grafting onto SiNPs for human serum albumin (HSA) and glucose oxidase (GOx). Binding affinity, selectivity, and specificity was compared to several other proteins using adsorption isotherms and surface plasmon resonance (SPR). The Langmuir–Freundlich adsorption model was used to obtain apparent binding constants (KLF) from binding isotherms of HSA (6.7 × 104) and GOx (4.7 × 104) to their respective AAs. These values were 4–300 fold larger compared to a series of nontemplate proteins. SPR binding studies of AAs with proteins attached to a gold surface confirmed good specificity and revealed faster binding for the target proteins compared to nontarget proteins. Target proteins retained their secondary structures upon binding. Binding capacity of AAHSA for HSA was 5.9 mg HSA/g compared to 1.4 mg/g for previously report imprinted silica beads imprinted with poly(aminophenyl)boronic acid. Also, 90% recovery for HSA spiked into 2% calf serum was found for AAHSA.

Targeted drug distribution in tumor extracellular fluid of GD2-expressing neuroblastoma patient-derived xenografts using SN-38-loaded nanoparticles conjugated to the monoclonal antibody 3F8

“…These results were supported by HR-SEM that showed the spherical morphology of all the NPs and the change of the surface topography from a very smooth for R-NPs to a patterned one for IgG3-NPs and 3F8-NPs (Figure 1). In the latter two, the conjugated antibodies were visualized as small dots (<20 nm), as previously reported upon the conjugation of other proteins to polymeric NPs [40] and in line with the reported size of IgG antibodies [41]. Upon analysis of the non-conjugated fraction of antibody in the supernatant of the reaction, the calculated efficiency of the conjugation process was 96.7 ± 3.0%, i.e., most of the antibody reacted with the NPs in the selected conditions.…”

Sodium hydroxide catalyzed monodispersed high surface area silica nanoparticles

“…The applications of SiNPs range from biosensors to drug-delivery vehicles [1–5]. Therefore, a fine-tuning of NP properties is sought.…”

Albumin removal from human serum using surface nanopockets on silica-coated magnetic nanoparticles

“…This approach provides binding sites that facilitate hydrophobic, hydrophilic and H-bonding interactions with target proteins similar to natural antibodies. 12 We demonstrated excellent selectivity and specificity of binding for HSA and glucose oxidase (GOx) on SiNPs, with binding constants 4 to 300-fold larger compared to a series of non-template proteins. Binding capacity increased 4-fold with combined use of the 4 different monomer types compared to using only a single monomer for templating.…”