Radio-synthesized protein-based nanoparticles for biomedical purposes

Protein Nanoparticles: Uniting the Power of Proteins with Engineering Design Approaches

Protein nanoparticles, PNPs, have played a long-standing role in food and industrial applications. More recently, their potential in nanomedicine has been more widely pursued. This review summarizes recent trends related to the preparation, application, and chemical construction of nanoparticles that use proteins as major building blocks. A particular focus has been given to emerging trends related to applications in nanomedicine, an area of research where PNPs are poised for major breakthroughs as drug delivery carriers, particle-based therapeutics or for non-viral gene therapy.

Measuring the concentration of protein nanoparticles synthesized by desolvation method: Comparison of Bradford assay, BCA assay, hydrolysis/UV spectroscopy and gravimetric analysis

The desolvation technique is one of the most popular methods for preparing protein nanoparticles for medicine, biotechnology, and food applications. We fabricated 11 batches of BSA nanoparticles and 2 batches of gelatin nanoparticles by desolvation method. BSA nanoparticles from 2 batches were cross-linked by heating at +70 °C for 2 h; other nanoparticles were stabilized by glutaraldehyde. We compared several analytical approaches to measuring their concentration: gravimetric analysis, bicinchoninic acid assay, Bradford assay, and alkaline hydrolysis combined with UV spectroscopy. We revealed that the cross-linking degree and method of cross-linking affect both Bradford and BCA assay. Direct measurement of protein concentration in the suspension of purified nanoparticles by dye-binding assays can lead to significant (up to 50-60%) underestimation of nanoparticle concentration. Quantification of non-desolvated protein (indirect method) is affected by the presence of small nanoparticles in supernatants and can be inaccurate when the yield of desolvation is low. The reaction of cross-linker with protein changes UV absorbance of the latter. Therefore pure protein solution is an inappropriate calibrator when applying UV spectroscopy for the determination of nanoparticle concentration. Our recommendation is to determine the concentration of protein nanoparticles by at least two different methods, including gravimetric analysis.

Semi-Solid Pharmaceutical Formulations for the Delivery of Papain Nanoparticles

Papain is a therapeutic enzyme with restricted applications due to associated allergenic reactions. Papain nanoparticles have shown to be safe for biomedical use, although a method for proper drug loading and release remains to be developed. Thus, the objective of this work was to develop and assess the stability of papain nanoparticles in a prototype semi-solid formulation suitable for dermatological or topical administrations. Papain nanoparticles of 7.0 ± 0.1 nm were synthesized and loaded into carboxymethylcellulose- and poly(vinyl alcohol)-based gels. The formulations were then assayed for preliminary stability, enzyme activity, cytotoxicity studies, and characterized according to their microstructures and protein distribution. The formulations were suitable for papain nanoparticle loading and provided a stable environment for the nanoparticles. The enzyme distribution along the gel matrix was homogeneous for all the formulations, and the proteolytic activity was preserved after the gel preparation. Both gels presented a slow release of the papain nanoparticles for four days. Cell viability assays revealed no potential cytotoxicity, and the presence of the nanoparticles did not alter the microstructure of the gel. The developed systems presented a potential for biomedical applications, either as drug delivery systems for papain nanoparticles and/or its complexes.

Carboxymethyl cellulose-based materials for infection control and wound healing: A review

The development of ideal wound dressing materials with excellent characteristics is currently a major demand in wound therapy. In recent years, carboxymethyl cellulose (CMC)-based wound dressing materials have been of immense attraction due to their noble properties, such as: biocompatibility, biodegradability, tissue resembling, low cost and non-toxic. It is used extensively, in a variety of applications in the biomedical and pharmaceutical fields. The hydrophilic nature of CMC, makes it possible to blend and cross-link with other materials, such as: synthetic polymers, natural polymers and inorganic materials and it enables the preparation of innovative wound dressing biomaterials. Hence, this review, focuses on the intrinsic characteristics of CMC-based wound dressing materials, including hydrogels, films, 3D printing, fibres, gauzes and their recent advancements in chronic wound healing.

Synthesis of papain nanoparticles by electron beam irradiation - A pathway for controlled enzyme crosslinking

Crosslinked enzyme aggregates comprise more stable and highly concentrated enzymatic preparations of current biotechnological and biomedical relevance. This work reports the development of crosslinked nanosized papain aggregates using electron beam irradiation as an alternative route for controlled enzyme crosslinking. The nanoparticles were synthesized in phosphate buffer using various ethanol concentrations and electron beam irradiation doses. Particle size increase was monitored using dynamic light scattering. The crosslinking formation by means of bityrosine linkages were measured by fluorescence spectra and the enzymatic activity was monitored using Na-Benzoyl-dl-arginine p-nitroanilide hydrochloride as a substrate. The process led to crosslinked papain nanoparticles with controlled sizes ranging from 6 to 11nm depending upon the dose and ethanol concentration. The irradiation atmosphere played an important role in the final bioactivity of the nanoparticles, whereas argon and nitrous oxide saturated systems were more effective than at atmospheric conditions in terms of preserving papain enzymatic activity. Highlighted advantages of the technique include the lack of monomers and crosslinking agents, quick processing with reduced bioactivity changes, and the possibility to be performed inside the final package simultaneously with sterilization.

Radiation-synthesized protein-based drug carriers: Size-controlled BSA nanoparticles

Nanotechnology has broadened the options for the delivery of agents of biotechnological and clinical relevance. Currently, attention has been driven towards the development of protein-based nanocarriers due to high the biocompatibility and site-specific delivery. In this work we report radiation-synthesized bovine serum albumin nanoparticles as an attempt to overcome limitations of available albumin particles, as a novel route for the development of crosslinked protein nanocarriers for the administration of chemotherapic agents or radiopharmaceuticals. Albumin containing phosphate buffer solutions were irradiated using γ-irradiation at distinct cosolvent concentrations-ethanol or methanol. Nanoparticle size was followed by DLS and bityrosine crosslinking formation using fluorescence measurements and SDS-PAGE. In addition, computational experiments were performed to elucidate the mechanism and pathways for the nanoparticle formation. The synthesis of BSA nanoparticles using γ-irradiation in the presence of a cosolvent allowed the formation of the nanoparticles from 7 to 70 nm without the use of any chemical crosslinker as confirmed by SDS-PAGE and DLS analysis. The combination of cosolvent and γ-irradiation allowed a fine tuning with regard to protein size.

Protein nanoparticles for therapeutic protein delivery

This review describes nanoparticles made from protein by self-assembly or desolvation as carriers for the delivery of therapeutic proteins.