Aminophenylboronic acid polymer nanoparticles for quantitation of glucose and for insulin release

Lyophilisation Improves Bioactivity and Stability of Insulin-Loaded Polymeric-Oligonucleotide Nanoparticles for Diabetes Treatment

The oral bioavailability of therapeutic proteins is limited by the gastrointestinal barriers. Encapsulation of labile proteins into nanoparticles is a promising strategy. In order to improve the stability of nanoparticles, lyophilisation has been used to remove water molecules from the suspension. Although various cryoprotections were employed in the preparation of lyophilised nanoparticles, the selection of cryoprotectant type and concentration in majority of the developed formulation was not justified. In this study, nanoparticles were fabricated by cationic chitosan and anionic Dz13Scr using complex coacervation. The effect of cryoprotectant types (mannitol, sorbitol, sucrose and trehalose) and their concentrations (1, 3, 5, 7, 10% w/v) on physiochemical properties of nanoparticles were measured. Cellular assays were performed to investigate the impact of selected cryoprotectant on cytotoxicity, glucose consumption, oral absorption mechanism and gastrointestinal permeability. The obtained results revealed that mannitol (7% w/v) could produce nanoparticles with small size (313.2 nm), slight positive charge and uniform size distribution. The addition of cryoprotectant could preserve the bioactivity of entrapped insulin and improve the stability of nanoparticles against mechanical stress during lyophilisation. The gastrointestinal absorption of nanoparticles is associated with both endocytic and paracellular pathways. With the use of 7% mannitol, lyophilised nanoparticles induced a significant glucose uptake in C2C12 cells. This work illustrated the importance of appropriate cryoprotectant in conservation of particle physiochemical properties, structural integrity and bioactivity. An incompatible cryoprotectant and inappropriate concentration could lead to cake collapse and formation of heterogeneous particle size populations.

Bio-nanotechnological advancement of orally administered insulin nanoparticles: Comprehensive review of experimental design for physicochemical characterization

Therapeutic proteins are labile macromolecules that are prone to degradation during production, freeze-drying and storage. Recent studies showed that nanoparticles can enhance the stability and oral bioavailability of encapsulated proteins. Several conventional approaches (enzyme inhibitors, mucoadhesive polymers) and novel strategies (surface modification, ligand conjugation, flash nano-complexation, stimuli-responsive drug delivery systems) have been employed to improve the physiochemical properties of nanoparticles such as size, zeta potential, morphology, polydispersity index, drug release kinetics and cell-targeting capacity. However, clinical translation of protein-based nanoparticle is limited due to poor experimental design, protocol non-compliance and instrumentation set-up that do not reflect the physiological conditions, resulting in difficulties in mass production of nanoparticles and waste in research funding. In order to address the above concerns, we conducted a comprehensive review to examine the experimental designs and conditions for physical characterization of protein-based nanoparticles. Reliable and robust characterization is essential to verify the cellular interactions and therapeutic potential of protein-based nanoparticles. Importantly, there are a number of crucial factors, which include sample treatment, analytical method, dispersants, sampling grid, staining, quantification parameters, temperature, drug concentration and research materials, should be taken into careful consideration. Variations in research protocol and unreasonable conditions that are used in optimization of pharmaceutical formulations can have great impact in result interpretation. Last but not least, we reviewed all novel instrumentations and assays that are available to examine mucus diffusion capacity, stability and bioactivity of protein-based nanoparticles. These include circular dichroism, fourier transform infrared spectroscopy, X-ray diffractogram, UV spectroscopy, differential scanning calorimetry, fluorescence spectrum, Förster resonance energy transfer, NMR spectroscopy, Raman spectroscopy, cellular assays and animal models.

A flexible-imprinted capacitive sensor for rapid detection of adrenaline

This article demonstrates a non-enzymatic biomimetic adrenaline capacitive sensor fabricated inexpensively by layer-by-layer (LbL) assembly. The LbL assembly consists of polydimethylsiloxane (PDMS) substrate, carbon nanotube-cellulose nanocrystals (CNC/CNT) nanofilms (first layer) with adrenaline imprinted poly (aniline/phenylboronic acid) (pANI/PBA) moieties (second layer). The flexible sensor has been effectively demonstrated for high sensitivity and selectivity in capacitive detection of adrenaline standard and adrenaline in real zebra fish brain sample. The molecularly imprinted adrenaline sensor exhibited linear response between 0.001  μM and 100  μM with a correlation coefficient of 0.9738 and detection limit (LOD) of 0.001  μM. The developed sensor demonstrated high adrenaline selectivity and good sensor to sensor reproducibility of 15.7% for molecularly imprinted films. The sensor precision for triplicate standard runs for different adrenaline concentrations ranged from 0.5 to 5.0%, indicative of the overall reliability and validity of the device. The inexpensive sensor remains stable over time, responding proportionately to doses of adrenaline, and as such effective as a dosimetric sensor for near real time continuous monitoring. Frugal in sample consumption (50 μL), the study suggested the practical utilization of the developed biosensor towards adrenaline detection in biological fluids.

Nanoparticle drug delivery systems: an excellent carrier for tumor peptide vaccines

In the past 40 years, the nanoparticle drug delivery system for tumor peptide vaccines has been widely studied which also reached a splendid result. Nanomaterial can enhance the targeting of vaccines, help vaccines enter the cells and trigger immune response by themselves. They also help in increasing cellular uptake, improving permeability and efficacy. Currently, several categories of nanopreparation, such as liposome, polymeric micelle, polymeric nanoparticle, gold nanoparticle and so on, are proved that they are appropriate for peptide vaccines. This review we discussed the possible mechanisms of nanomaterial's action on the regulation of immunological functions and several major applications of this advanced drug delivery system for tumor peptide vaccine.

Modification of bovine serum albumin with aminophenylboronic acid as glycan sensor based on surface plasmon resonance and isothermal titration calorimetry

Aminophenylboronic acid (ABA) modified bovine serum albumin (BSA) was prepared as neolectin and its interactions with oligosaccharides and glycopolymer were studied by surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). The conjugation between the primary amine group of the ABA molecule and lysine residues on BSA was performed with an adipate-based strategy to afford the synthetic neoprotein. The number of ABA molecules loaded to BSA surface was determined by matrix-assisted laser desorption/ionization – time of flight (MALDI-TOF) mass spectrometry. In the BSA-ABA and sugar interaction study, no signal was observed for both the SPR and ITC sensor platform using monosaccharides as the analyte, indicating a weak binding affnity, while the galactose modified polymer showed an enhanced response. The binding affinities of the galactosyl-polymer to BSA-ABA from SPR and ITC data were in the micromolar range.