Protein-Based Nanoparticle Preparation via Nanoprecipitation Method

Metal-Organic Framework Induced Stabilization of Proteins in Polymeric Nanoparticles

Developing protein confinement platforms is an attractive research area that not only promotes protein delivery but also can result in artificial environment mimicking of the cellular one, impacting both the controlled release of proteins and the fundamental protein biophysics. Polymeric nanoparticles (PNPs) are attractive platforms to confine proteins due to their superior biocompatibility, low cytotoxicity, and controllable release under external stimuli. However, loading proteins into PNPs can be challenging due to the potential protein structural perturbation upon contacting the interior of PNPs. In this work, we developed a novel approach to encapsulate proteins in PNPs with the assistance of the zeolitic imidazolate framework (ZIF). Here, ZIF offers an additional protection layer to the target protein by forming the protein@ZIF composite via aqueous-phase cocrystallization. We demonstrated our platform using a model protein, lysozyme, and a widely studied PNP composed of poly(ethylene glycol)-poly(lactic-co-glycolic acid) (PEG-PLGA). A comprehensive study via standard loading and release tests as well as various spectroscopic techniques was carried out on lysozyme loaded onto PEG-PLGA with and without ZIF protection. As compared with the direct protein encapsulation, an additional layer with ZIF prior to loading offered enhanced loading capacity, reduced leaching, especially in the initial stage, led to slower release kinetics, and reduced secondary structural perturbation. Meanwhile, the function, cytotoxicity, and cellular uptake of proteins encapsulated within the ZIF-bound systems are decent. Our results demonstrated the use of ZIF in assisting in protein encapsulation in PNPs and established the basis for developing more sophisticated protein encapsulation platforms using a combination of materials of diverse molecular architectures and disciplines. As such, we anticipate that the protein-encapsulated ZIF systems will serve as future polymer protein confinement and delivery platforms for both fundamental biophysics and biochemistry research and biomedical applications where protein delivery is needed to support therapeutics and/or nutrients.

Antibody desolvation with sodium chloride and acetonitrile generates bioactive protein nanoparticles

About 30% of the FDA approved drugs in 2021 were protein-based therapeutics. However, therapeutic proteins can be unstable and rapidly eliminated from the blood, compared to conventional drugs. Furthermore, on-target but off-tumor protein binding can lead to off-tumor toxicity, lowering the maximum tolerated dose. Thus, for effective treatment therapeutic proteins often require continuous or frequent administration. To improve protein stability, delivery and release, proteins can be encapsulated inside drug delivery systems. These drug delivery systems protect the protein from degradation during (targeted) transport, prevent premature release and allow for long-term, sustained release. However, thus far achieving high protein loading in drug delivery systems remains challenging. Here, the use of protein desolvation with acetonitrile as an intermediate step to concentrate monoclonal antibodies for use in drug delivery systems is reported. Specifically, trastuzumab, daratumumab and atezolizumab were desolvated with high yield (∼90%) into protein nanoparticles below 100 nm with a low polydispersity index (<0.2). Their size could be controlled by the addition of low concentrations of sodium chloride between 0.5 and 2 mM. Protein particles could be redissolved in aqueous solutions and redissolved antibodies retained their binding activity as evaluated in cell binding assays and exemplified for trastuzumab in an ELISA.

Mitigating amphotericin B cytotoxicity through gliadin-casein nanoparticles: Insights into synthesis, optimization, characterization, in vitro release and cytotoxicity evaluation

Amphotericin B (AmB) is a widely used antifungal agent; however, its clinical application is limited due to severe side effects and nephrotoxicity associated with parenteral administration. In recent years, there has been growing interest in the utilization of food-grade materials as innovative components for nanotechnology-based drug delivery systems. This study introduces gliadin/casein nanoparticles encapsulating AmB (AmB_GliCas NPs), synthesized via antisolvent precipitation. Formulation was refined using a 24 factorial design, assessing the influence of gliadin and casein concentrations, as well as organic and aqueous phase volumes, on particle size, polydispersity index (PDI), and zeta potential. The optimal composition with 2 % gliadin, 0.5 % casein, and a 1:5 organic-to-aqueous phase ratio, yielded nanoparticles with a 442 nm size, a 0.307 PDI, a -20 mV zeta potential, and 82 % entrapment efficiency. AmB was confirmed to be amorphous within the nanoparticles by X-ray diffraction. These NPs released AmB sustainably over 96 h, primarily in its monomeric form. Moreover, NPs maintained stability in simulated gastrointestinal fluids with minimal drug release and showed significantly lower hemolytic activity and cytotoxicity on Vero cells than free AmB, suggesting their promise for oral AmB delivery.

Step-By-Step Standardization of the Bottom-Up Semi-Automated Nanocrystallization of Pharmaceuticals: A Quality By Design and Design of Experiments Joint Approach

Nanosized drug crystals have been reported with enhanced apparent solubility, bioavailability, and therapeutic efficacy compared to microcrystal materials, which are not suitable for parenteral administration. However, nanocrystal design and development by bottom-up approaches are challenging, especially considering the non-standardized process parameters in the injection step. This work aims to present a systematic step-by-step approach through Quality-by-Design (QbD) and Design of Experiments (DoE) for synthesizing drug nanocrystals by a semi-automated nanoprecipitation method. Curcumin is used as a drug model due to its well-known poor water solubility (0.6 µg mL-1 , 25 °C). Formal and informal risk assessment tools allow identifying the critical factors. A fractional factorial 24-1 screening design evaluates their impact on the average size and polydispersity of nanocrystals. The optimization of significant factors is done by a Central Composite Design. This response surface methodology supports the rational design of the nanocrystals, identifying and exploring the design space. The proposed joint approach leads to a reproducible, robust, and stable nanocrystalline preparation of 316 nm with a PdI of 0.217 in compliance with the quality profile. An orthogonal approach for particle size and polydispersity characterization allows discarding the formation of aggregates. Overall, the synergy between advanced data analysis and semi-automated standardized nanocrystallization of drugs is highlighted.

Factors Affecting the Synthesis of Bovine Serum Albumin Nanoparticles Using the Desolvation Method

Currently, protein-based nanoparticles are in high demand as drug delivery systems due to their exceptional qualities, including nontoxicity, nonantigenicity, and biodegradability. Other qualities include high nutritional value, abundance of renewable resources, excellent drug binding capacity, greater stability during storage and in vivo, as well as ease of upgrading during manufacture. Examples of protein suitable for this purpose include ovalbumin (OVA) derived from egg white, human serum albumin (HSA), and bovine serum albumin (BSA). To create albumin nanoparticles, six different processes have been investigated in depth and are frequently used in drug delivery systems. These included desolvation, thermal gelation, emulsification, NAB technology, self-assembly, and nanospray drying. Several experimental conditions in the synthesis of albumin nanoparticles can affect the physicochemical characterization. Therefore, this study aimed to provide an overview of various experimental conditions capable of affecting the physicochemical characteristics of BSA nanoparticles formed using the desolvation method. By considering the variation in optimal experimental conditions, a delivery system of BSA nanoparticles with the best physicochemical characterization results could be developed.

Use of Albumin for Drug Delivery as a Diagnostic and Therapeutic Tool

Drug delivery is an important topic that has attracted the attention of researchers in recent years. Albumin nanoparticles play a significant role in drug delivery as a carrier due to their unique characteristics. Albumin is non-toxic, biocompatible, and biodegradable. Its structure is such that it can interact with different drugs, which makes the treatment of the disease faster and also reduces the side effects of the drug. Albumin nanoparticles can be used in the diagnosis and treatment of many diseases, including cancer, diabetes, Alzheimer's, etc. These nanoparticles can connect to some compounds, such as metal nanoparticles, antibodies, folate, etc. and create a powerful nanostructure for drug delivery. In this paper, we aim to investigate albumin nanoparticles in carrier format for drug delivery application. In the beginning, different types of albumin and their preparation methods were discussed, and then albumin nanoparticles were discussed in detail in diagnosing and treating various diseases.

Dual-Antigen Subunit Vaccine Nanoparticles for Scrub Typhus

Orientia tsutsugamushi is the causative pathogen of scrub typhus, an acute febrile disease prevalent in the Asia-Pacific region that is spread to people through chigger bites. Despite the emerging threat, there is no currently available vaccine against O. tsutsugamushi. Here, we developed dual-antigen subunit vaccine nanoparticles using recombinant 47 kD and 56 kD proteins, which are immunogenic outer membrane antigens of O. tsutsugamushi. The biocompatible protein vaccine nanoparticles were formed via desolvation of r56 or r47E antigens with acetone, coating with an additional layer of the 56 kD protein, and stabilization with reducible homobifunctional DTSSP and heterobifunctional SDAD crosslinkers. The dual-antigen subunit vaccine nanoparticles significantly improved antigen-specific antibody responses in vaccinated mice. Most importantly, the dual-antigen nanoparticles coated with an additional layer of the 56 kD protein were markedly more immunogenic than soluble antigens or single-antigen nanoparticles in the context of cellular immune responses. Given the significance of cellular immune responses for protection against O. tsutsugamushi, these results demonstrate the potent immunogenicity of dual-layered antigen nanoparticles and their potential as a promising strategy for developing vaccines against scrub typhus.

Preparation of protein-loaded nanoparticles based on poly(succinimide)-oleylamine for sustained protein release: a two-step nanoprecipitation method

Currently, the treatment for acute disease encompasses the use of various biological drugs (BDs). However, the utilisation of BDs is limited due to their rapid clearance and non-specific accumulation in unwanted sites, resulting in a lack of therapeutic efficacy together with adverse effects. While nanoparticles are considered good candidates to resolve this problem, some available polymeric carriers for BDs were mainly designed for long-term sustained release. Thus, there is a need to explore new polymeric carriers for the acute disease phase that requires sustained release of BDs over a short period, for example for thrombolysis and infection. Poly(succinimide)-oleylamine (PSI-OA), a biocompatible polymer with a tuneable dissolution profile, represents a promising strategy for loading BDs for sustained release within a 48-h period. In this work, we developed a two-step nanoprecipitation method to load the model protein (e.g. bovine serum albumin and lipase) on PSI-OA. The characteristics of the nanoparticles were assessed based on various loading parameters, such as concentration, stirring rate, flow rate, volume ratio, dissolution and release of the protein. The optimised NPs displayed a size within 200 nm that is suitable for vasculature delivery to the target sites. These findings suggest that PSI-OA can be employed as a carrier for BDs for applications that require sustained release over a short period.

Preparation and Optimization of Bovine Serum Albumin Nanoparticles as a Promising Gelling System for Enhanced Nasal Drug Administration

Bovine serum albumin (BSA) has been used extensively as a suitable carrier system for alternative drug delivery routes, such as nasal administration. However, the optimization of BSA nanoparticles with respect to their nasal applicability has not been widely studied. The present study focuses on the characterization of BSA nanoparticles prepared using the desolvation method, followed by a gelation process to facilitate intranasal drug delivery. The results demonstrated that the ratio of BSA and the desolvating agent, ethanol, played a critical role in the nanoparticle characteristics of the BSA nanogel matrices (BSA-NGs). Based on the gelling properties, the formulations of BSA-NG 2, BSA-NG 4, and BSA-NG 6 were selected for further investigation. The Raman spectra confirmed that there were no specific changes to the secondary structures of the BSA. The mucoadhesion studies revealed moderately high mucoadhesive properties, with a mucin binding efficiency (MBE) value of around 67%, allowing the dose to avoid elimination due to rapid mucociliary clearance of the nasal passage. Via studying the nexus of the carrier system, BSA-NGs loaded with dexamethasone as a model drug were prepared and evaluated by differential scanning calorimetry (DSC) and thermal gravimetry (TG), ascertaining that no ethanol remained in the samples after the freeze-drying process. Furthermore, the viscosity measurements exhibited moderate viscosity, which is suitable for nasal liquid preparations. The in vitro release studies performed with a simulated nasal electrolyte solution (SNES) medium showed 88.15-95.47% drug release within 4 h. In conclusion, BSA nanoparticle gelling matrices can offer potential, value-added drug delivery carriers for improved nasal drug administration.

EGFR targeted albumin nanoparticles of oleanolic acid: In silico screening of nanocarrier, cytotoxicity and pharmacokinetics for lung cancer therapy

This study aimed to develop cetuximab (CTX) functionalized albumin nanoparticles (ALB-NPs) of oleanolic acid for EGFR targeted lung cancer therapy. The molecular docking methodology has been applied for a selection of suitable nanocarrier. Various physicochemical parameters like particle size, polydispersity, zeta potential, morphology, entrapment efficiency, and in-vitro drug release of all the ALB-NPs were analyzed. Furthermore, the in-vitro qualitative and quantitative cellular uptake study revealed that higher uptake of CTX conjugated ALB-NPs than nontargeted ALB-NPs in A549 cells. The in-vitro MTT assay revealed that the IC50 value of CTX-OLA-ALB-NPs (4.34 ± 1.90 μg/mL) was significantly reduced (p < 0.001) than OLA-ALB-NPs (13.87 ± 1.28 μg/mL) in A-549 cells. CTX-OLA-ALB-NPs caused apoptosis in A-549 cells at concentrations equivalent to its IC50 value and blocked the cell cycle in the G0/G1 phases. The hemocompatibility, histopathology and lung safety study confirmed the biocompatibility of the developed NPs. In vivo ultrasound and photoacoustic imaging confirmed the targeted delivery of the NPs to lung cancer. The findings demonstrated that CTX-OLA-ALB-NPs have potential for site-specific delivery of OLA for effective and targeted therapy of lung carcinoma.

The mechanism, biopolymers and active compounds for the production of nanoparticles by anti-solvent precipitation: A review

The anti-solvent precipitation method has been investigated to produce biopolymeric nanoparticles in recent years. Biopolymeric nanoparticles have better water solubility and stability when compared with unmodified biopolymers. This review article focuses on the analysis of the state of the art available in the last ten years about the production mechanism and biopolymer type, as well as the used of these nanomaterials to encapsulate biological compounds, and the potential applications of biopolymeric nanoparticles in food sector. The revised literature revealed the importance to understand the anti-solvent precipitation mechanism since biopolymer and solvent types, as well as anti-solvent and surfactants used, can alter the biopolymeric nanoparticles properties. In general, these nanoparticles have been produced using polysaccharides and proteins as biopolymers, especially starch, chitosan and zein. Finally, it was identified that those biopolymers produced by anti-solvent precipitation were used to stabilize essential oils, plant extracts, pigments, and nutraceutical compounds, promoting their application in functional foods.

Solid lipid-based nanoparticulate system for sustained release and enhanced in-vitro cytotoxic effect of 5-fluorouracil on skin Melanoma and squamous cell carcinoma

The present study aimed to prepare solid lipid-based nanoparticles (SLNs) using Precirol® ATO 5 as solid lipid and Poloxamer 188 and Tween 80 as surfactant and co-surfactant respectively, and SLNs-derived gel for sustained delivery, enhanced in-vitro cytotoxicity, enhanced cellular uptake of 5-FU and enhanced permeation of 5-FU across the skin. The 5-FU-loaded SLNs were prepared by the hot melt encapsulation method and converted into SLN-derived gel using a gelling agent (Carbopol 940). The 5-FU-loaded SLNs had a particle size in the range of 76.82±1.48 to 327±4.46 nm, zeta potential between -11.3±2.11 and -28.4±2.40 mV, and entrapment efficiency (%) in range of 63.46±1.13 and 76.08±2.42. The FTIR analysis depicted that there was no chemical interaction between 5-FU and formulation components. Differential scanning calorimetric analysis showed thermal stability of 5-FU in the nanoparticles and powdered X-ray diffraction analysis revealed successful incorporation of 5-FU in nanoparticles. The in-vitro release study of 5-FU-loaded SLNs showed biphasic release behavior with initial burst release followed by sustained release over 48 hr. The 5-FU-loaded SLNs showed a greater cytotoxic effect on skin melanoma (B16F10 cells) and squamous cell carcinoma (A-431 cells) as compared to free 5-FU drug solution after 48 hr. Flow cytometry and fluorescence microscopy displayed enhanced quantitative and qualitative cellular uptake of SLNs. The SLNs formulation showed acceptable safety and biocompatible profile after an acute toxicity study in Wistar rats. Moreover, ex-vivo permeation studies depicted 2.13±0.076 folds enhanced flux of 5-FU-loaded SLN derived gel compared to 5-FU plain gel, and skin retention studies revealed target efficiency (%) 2.54±0.03 of 5-FU-loaded SLN derived gel compared to 5-FU plain gel.

Stable Enzymatic Nanoparticles from Nucleases, Proteases, Lipase and Antioxidant Proteins with Substrate-Binding and Catalytic Properties

Limited membrane permeability and biodegradation hamper the intracellular delivery of the free natural or recombinant enzymes necessary for compensatory therapy. Nanoparticles (NP) provide relative protein stability and unspecific endocytosis-mediated cellular uptake. Our objective was the fabrication of NP from 7 biomedicine-relevant enzymes, including DNase I, RNase A, trypsin, chymotrypsin, catalase, horseradish peroxidase (HRP) and lipase, the analysis of their conformation stability and enzymatic activity as well as possible toxicity for eukaryotic cells. The enzymes were dissolved in fluoroalcohol and mixed with 40% ethanol as an anti-solvent with subsequent alcohol evaporation at high temperature and low pressure. The shapes and sizes of NP were determined by scanning electron microscopy (SEM), atomic force microscopy (AFM) and dynamic light scattering (DLS). Enzyme conformations in solutions and in NP were compared using circular dichroism (CD) spectroscopy. The activity of the enzymes was assayed with specific substrates. The cytotoxicity of the enzymatic NP (ENP) was studied by microscopic observations and by using an MTT test. Water-insoluble ENP of different shapes and sizes in a range 50-300 nm consisting of 7 enzymes remained stable for 1 year at +4 °C without any cross-linking. CD spectroscopy of the ENP permitted us to reveal changes in proportions of α-helixes, β-turns and random coils in comparison with fresh enzyme solutions in water. Despite the minor conformation changes of the proteins in the ENP, the enzymes retained their substrate-binding and catalytic properties. Among the studied bioactive ENP, only DNase NP were highly toxic for 3 cell lines with granulation in 1 day posttreatment, whereas other NP were less toxic (if any). Taken together, the enzymes in the stable ENP retained their catalytic activity and might be used for intracellular delivery.

Photoluminescent Gold/BSA Nanoclusters (AuNC@BSA) as Sensors for Red-Fluorescence Detection of Mycotoxins

The BSA-encapsulated gold nanoclusters (AuNC@BSA) have drawn considerable interest and demonstrated applications as biological sensors. In this study, we demonstrated that the red-emitting AuNC@BSA prepared using a modified procedure fully retained the binding of standard BSA-ligands (small molecule drugs), significantly improving fluorescence detection in some cases due to the red-emission property. Further, we showed that AuNC@BSA efficiently bind a series of aflatoxin-related mycotoxins as well as the aliphatic mycotoxin FB1, reporting interactions in the nanomolar range by instantaneous emission change at 680 nm. Such red emission detection is advantageous over current detection strategies for the same mycotoxins, based on complex mass spectrometry procedures or, eventually (upon chemical modification of the mycotoxin), by fluorescence detection in the UV range (<400 nm). The later technique yields fluorescence strongly overlapping with the intrinsic absorption and emission of biorelevant mixtures in which mycotoxins appear. Thus, here we present a new approach using the AuNC@BSA red fluorescence reporter for mycotoxins as a fast, cheap, and simple detection technique that offers significant advantages over currently available methods.

Self-assembling nanocarriers from engineered proteins: Design, functionalization, and application for drug delivery

Self-assembling proteins are valuable building blocks for constructing drug nanocarriers due to their self-assembly behavior, monodispersity, biocompatibility, and biodegradability. Genetic and chemical modifications allow for modular design of protein nanocarriers with effective drug encapsulation, targetability, stimuli responsiveness, and in vivo half-life. Protein nanocarriers have been developed to deliver various therapeutic molecules including small molecules, proteins, and nucleic acids with proven in vitro and in vivo efficacy. This article reviews recent advances in protein nanocarriers that are not derived from natural protein nanostructures, such as protein cages or virus like particles. The protein nanocarriers described here are self-assembled from rationally or de novo designed recombinant proteins, as well as recombinant proteins complexed with other biomolecules, presenting properties that are unique from those of natural protein carriers. Design, functionalization, and therapeutic application of protein nanocarriers will be discussed.

Fabrication of protein nanomaterials as delivery systems

Bioactive compounds in foods, nutraceuticals and pharmaceutical have been gaining interest due to health benefits, which can help to reduce the risk of certain chronic diseases. Recently, nanoencapsulation have attract attention because it is an efficient and promising approach for protection of bioactive compounds, and delivery them to the target physiological sites for controlled release and improvement absorption. Food proteins are promising materials to be fabricated into a variety of nanostructured delivery systems because of their high nutritional value, good functional properties, and health-benefiting effects. Various techniques and approaches are utilized to prepare nanostructured food protein. This chapter introduces the major techniques for the fabrication of nanoparticles and nanoemulsions from food proteins. The basic principles, advantages, and limitations of the techniques are discussed. The encapsulation and release of bioactive compounds in different nanostructured food proteins are illustrated in specific case studies. Due to the fast growing interest of bioactive encapsulation in various sectors, this chapter is of importance for guiding the development of nanostructured food protein loaded with bioactive ingredients for food, nutraceutical and pharmaceutical applications.

Preparation of Zein-Based Nanoparticles: Nanoprecipitation versus Microfluidic-Assisted Manufacture, Effects of PEGylation on Nanoparticle Characteristics and Cellular Uptake by Melanoma Cells

Background

The manufacture of nanoparticles using manual methods is hampered by its challenging scale-up and poor reproducibility. To overcome this issue, the production of zein nanoparticles entrapping a lipophilic drug model, coumarin-6, by using a microfluidic system was assessed in this study. The influence of PEG density and chain length on zein nanoparticle characteristics, as well as their uptake efficacy in melanoma cancer cells, was also evaluated.

Methods

Zein nanoparticles were prepared by both manual and microfluidic approaches to allow comparison between the two processes. PEGylated zein nanoparticles with various PEG densities and chain lengths were produced by nanoprecipitation and characterized. Their cellular uptake was evaluated on B16F10 melanoma cancer cells in vitro.

Results

Zein nanoparticles have successfully been produced by both manual and microfluidic approaches. Parameters such as total flow rate and flow rate ratio of the aqueous and organic phases in microfluidic process, as well as the method preparation and aqueous to organic phase volume ratio during nanoprecipitation, have been shown to strongly influence the characteristics of the resulting nanoparticles. Continuous microfluidics led to the production of nanoparticles with low yield and drug entrapment, unlike nanoprecipitation, which resulted in zein nanoparticles with an appropriate size and an optimal drug entrapment efficiency of 64%. The surface modification of the nanoparticles produced by nanoprecipitation, with lower PEG density and shorter PEG chain length made mPEG5K-zein (0.5:1) the most favorable formulation in our study, resulting in enhanced stability and higher coumarin-6 uptake by melanoma cancer cells.

Conclusion

mPEG5K-zein (0.5:1) nanoparticles prepared by nanoprecipitation were the most promising formulation in our study, exhibiting increased stability and enhancing coumarin-6 uptake by melanoma cancer cells.

Progress in the drug encapsulation of poly(lactic-co-glycolic acid) and folate-decorated poly(ethylene glycol)-poly(lactic-co-glycolic acid) conjugates for selective cancer treatment

Poly(lactic-co-glycolic acid) (PLGA) is a US Food and Drug Administration (FDA)-approved polymer used in humans in the forms of resorbable sutures, drug carriers, and bone regeneration materials. Recently, PLGA-based conjugates have been extensively investigated for cancer, which is the second leading cause of death globally. This article presents an account of the literature on PLGA-based conjugates, focusing on their chemistries, biological activity, and functions as targeted drug carriers or sustained drug controllers for common cancers (e.g., breast, prostate, and lung cancers). The preparation and drug encapsulation of PLGA nanoparticles and folate-decorated poly(ethylene glycol)-poly(lactic-co-glycolic acid) (FA-PEG-PLGA) conjugates are discussed, along with several representative examples. Particularly, the reactions used for preparing drug-conjugated PLGA and FA-PEG-PLGA are emphasized, with the associated chemistries involved in the formation of structures and their biocompatibility with internal organs. This review provides a deeper understanding of the constituents and interactions of PLGA-conjugated materials to ensure successful conjugation in PLGA material design and the subsequent biomedical applications.

BSA-PEI Nanoparticle Mediated Efficient Delivery of CRISPR/Cas9 into MDA-MB-231 Cells

The discovery of bacterial-derived Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system has revolutionized genome engineering and gene therapy due to its wide range of applications. One of the major challenging issues in CRISPR/Cas system is the lack of an efficient, safe, and clinically suitable delivery of the system’s components into target cells. Here, we describe the development of polyethylenimine coated-bovine serum albumin nanoparticles (BSA-PEI NPs) for efficient delivery of CRISPR/Cas9 system in both DNA (px458 plasmid) and ribonucleoprotein (RNP) forms into MDA-MB-231 human breast cancer cell line. Our data showed that synthesized BSA-PEI (BP) NPs delivered plasmid px458 at concentrations of 0.15, 0.25, and 0.35 µg/µl with efficiencies of approximately 29.7, 54.8, and 84.1% into MDA-MB-231 cells, respectively. Our study demonstrated that Cas9/sgRNA RNP complex efficiently (~ 92.6%) delivered by BSA-PEI NPs into the same cells. Analysis of toxicity and biocompatibility of synthesized NPs on human red blood cells, MDA-MB-231 cells, and mice showed that the selected concentration (28 µg/µl) of BSA-PEI NPs for transfection had no remarkable toxicity effects. Thus, obtained results suggest BSA-PEI NPs as one of the most promising carrier for delivering CRISPR/Cas9 to target cells.

Hydrogel Containing Solid Lipid Nanoparticles Loaded with Argan Oil and Simvastatin: Preparation, In Vitro and Ex Vivo Assessment

Transdermal hydrogels have the potential to improve therapeutic outcomes via enhancing bioavailability and reducing toxicity associated with oral delivery. The goal of the present study was to formulate and optimise argan oil loaded transdermal hydrogel containing lipid nanoparticles. The high pressure homogenization (HPH) method was utilised to fabricate Simvastatin loaded solid lipid nanoparticles (SIM-SLNs) with precirol ATO 5 as a lipid core and Poloxamer 407 (P407) to stabilise the core. The optimised nanoformulation was characterised for its particle diameter, zeta potential, surface morphology, entrapment efficiency, crystallinity and molecular interaction. Furthermore, transdermal hydrogel was characterised for physical appearance, rheology, pH, bio adhesion, extrudability, spreadability and safety profile. In vitro and ex vivo assays were executed to gauge the potential of SLNs and argan oil for transdermal delivery. The mean particle size, zeta potential and polydispersity index (PDI) of the optimised nanoparticles were 205 nm, −16.6 mV and 0.127, respectively. Crystallinity studies and Fourier transform infrared (FTIR) analysis revealed no molecular interaction. The in vitro release model explains anomalous non-Fickian release of drug from matrix system. Ex vivo skin penetration studies conducted through a fluorescence microscope confirmed penetration of the formulation across the stratum corneum. Hydrogel plays a crucial role in controlling the burst release and imparting the effect of argan oil as hypolipidemic agent and permeation enhancer.

Design and Evaluation of pH-Sensitive Nanoformulation of Bergenin Isolated from Bergenia ciliata

The aim of the current study is extraction and isolation of bergenin from Bergenia ciliata and fabrication of pH-sensitive Eudragit^® L100 (EL100) polymeric nanoparticles (NP) to tackle limitations of solubility. Bergenin-loaded EL100 nanoparticles (BN-NP) were fabricated via nanoprecipitation and an experimental design was conducted for optimization. A reverse phase-high performance liquid chromatography (RP-HPLC) method was developed for the quantitation of bergenin. The optimized nanoformulation was characterized by its particle size, morphology, loading capacity, entrapment efficiency, drug-excipient interaction and crystallinity. An in vitro assay was executed to gauge the release potential of pH-sensitive nanoformulation. The mean particle size, zeta potential and polydispersity index (PDI) of the optimized nanoparticles were observed to be 86.17 ± 2.1 nm, -32.33 ± 5.53 mV and 0.30 ± 0.03, respectively. The morphological analysis confirmed the spherical nature of the nanoparticles. Drug loading capacity and entrapment efficiency were calculated to be 16 ± 0.34% and 84 ± 1.3%, respectively. Fourier transform infrared spectroscopy (FTIR) studies unfolded that no interaction was present between the drug and the excipients in the nanoformulation. Crystallography studies revealed that the crystalline nature of bergenin was changed to amorphous and the nanoformulation was stable for up to 3 months at 40 °C. The present study confirms that bergenin isolation can be scaled up from abundantly growing B. ciliata. Moreover, it could also be delivered by entrapment in stimuli-responsive polymer, preventing the loss of drug in healthy tissues.

Valorization of agro-industrial biowaste to green nanomaterials for wastewater treatment: Approaching green chemistry and circular economy principles

Water pollution is one of the most critical issues worldwide and is a priority in all scientific agendas. Green nanotechnology presents a plethora of promising avenues for wastewater treatment. This review discusses the current trends in the valorization of zero-cost, biodegradable, and readily available agro-industrial biowaste to produce green bio-nanocatalysts and bio-nanosorbents for wastewater treatment. The promising roles of green bio-nanocatalysts and bio-nanosorbents in removing organic and inorganic water contaminants are discussed. The potent antimicrobial activity of bio-derived nanodisinfectants against water-borne pathogenic microbes is reviewed. The bioactive molecules involved in the chelation and tailoring of green synthesized nanomaterials are highlighted along with the mechanisms involved. Furthermore, this review emphasizes how the valorization of agro-industrial biowaste to green nanomaterials for wastewater treatment adheres to the fundamental principles of green chemistry, circular economy, nexus thinking, and zero-waste manufacturing. The potential economic, environmental, and health impacts of valorizing agro-industrial biowaste to green nanomaterials are highlighted. The challenges and future outlooks for the management of agro-industrial biowaste and safe application of green nanomaterials for wastewater treatment are summarized.

Journey to the Market: The Evolution of Biodegradable Drug Delivery Systems

Biodegradable polymers have been used as carriers in drug delivery systems for more than four decades. Early work used crude natural materials for particle fabrication, whereas more recent work has utilized synthetic polymers. Applications include the macroscale, the microscale, and the nanoscale. Since pioneering work in the 1960’s, an array of products that use biodegradable polymers to encapsulate the desired drug payload have been approved for human use by international regulatory agencies. The commercial success of these products has led to further research in the field aimed at bringing forward new formulation types for improved delivery of various small molecule and biologic drugs. Here, we review recent advances in the development of these materials and we provide insight on their drug delivery application. We also address payload encapsulation and drug release mechanisms from biodegradable formulations and their application in approved therapeutic products.

Development of an intelligent, stimuli-responsive transdermal system for efficient delivery of Ibuprofen against rheumatoid arthritis

The present study aimed to fabricate and evaluate the therapeutic efficacy of pH-responsive Ibuprofen (IB) nanoparticles (NPs) loaded transdermal hydrogel against rheumatoid arthritis (RA). The IB loaded Eudragit® L 100 (EL 100) nanoparticles were formulated through a modified nanoprecipitation technique and optimized using central composite design software. The optimized NPs were loaded into Carbopol® 934-based hydrogel by solvent evaporation method and were analyzed for physicochemical characteristics. The mean particle size of the prepared NPs was 48 nm with an entrapment efficiency of 90%. The transdermal hydrogel showed a pH-responsive sustained drug release and high penetration through the skin. Moreover, the prepared nanocarrier system exhibited therapeutic efficacy at inflamed joints' sites both in acute and chronic RA mice model. The therapeutic efficacy of the prepared formulation was confirmed through the results of various behavioral, biochemical, and cytokines-based assays. Similarly, the assessment of histopathological and radiological images, as well as the skin irritation studies further strengthens the potential use of the prepared formulation through the transdermal route. The current findings suggested that IB loaded pH-responsive NPs based transdermal hydrogel can be used as an efficient agent to manage RA.

Doxorubicin-loaded, pH-sensitive Albumin Nanoparticles for Lung Cancer Cell Targeting

In recent decades, scientific and medical communities have continuously sought new methods and chemistries to improve the treatment of cancer. Among many types of nanoparticles considered as carriers for drug delivery, the protein ones count among the safest. The present study aimed to investigate the physicochemical and biological effects of the supplementation of albumin nanoparticles with doxorubicin (DOX). DOX was co-precipitated with albumin in a desolvation process and entrapped inside the cross-linked albumin nanoparticles, where it disrupted the protein structure at various levels: (a) it reduced the particle size distribution homogeneity; (b) it extended the peptide bond length; (c) it lowered the thermal stability of albumin; (d) it lowered the crystallinity of the protein. Physicochemical mechanisms underlying these changes are discussed. The drug release was incomplete under the physiological conditions, but the nanoparticles fully released their chemotherapeutic payload when pH was decreased by a single unit from the physiological value. Because the extracellular pH of tumors is usually by a single pH unit lower than that of healthy tissues, this environmentally responsive drug delivery system composed of albumin nanoparticles may be applicable in the targeting of cancer cells. In vitro assays against human lung cancer cells demonstrated that DOX released from albumin nanoparticles had a four times higher apoptotic activity than the equivalent concentration of free DOX. The ability of albumin to prevent the agglomeration of partially hydrophobic DOX and release it at a sustained, zero-order rate over the first 12 h of incubation, with no burst effect, explains this ability to augment the activity of DOX against the lung cancer cells.

Construction and characterization of Juglans regia L. polyphenols nanoparticles based on bovine serum albumin and Hohenbuehelia serotina polysaccharides, and their gastrointestinal digestion and colonic fermentation in vitro

Herein, we report the construction and characterization of nanoparticles based on bovine serum albumin and Hohenbuehelia serotina polysaccharides for the delivery of polyphenols isolated from the shells of Juglans regia L. (BSA-JRP-HSP NPs). We also systematically investigated their gastrointestinal digestion and colonic fermentation characteristics in vitro. BSA-JRP-HSP NPs, with amorphous properties and regular spherical morphological features, have a high encapsulation efficiency of 88.47 ± 0.04%, average particle size of 285.7 ± 3.1 nm, and zeta potential of -12.20 ± 0.61 mV, and they exhibit excellent photothermal stabilities and strong mucin adhesion capacity. Through measurements of gastrointestinal digestion and colonic fermentation in vitro, the results suggest that BSA-JRP-HSP NPs presented well-sustained release characteristics for preventing the biodegradation of JRP during gastrointestinal digestion. After gastrointestinal digestion, BSA-JRP-HSP NPs could modulate the composition and structure of gut microbiota, promoting the growth of beneficial bacterial (e.g. Prevotella, Dialister, Akkermansia, etc.) and inhibiting the growth of pathogenic bacteria (e.g. Bacteroides, Phascolarctobacterium, Lachnospiracea incertae sedis, etc.). The production of short-chain fatty acids (SCFAs) including acetic acid, propionic acid, and butyric acid was remarkably enhanced by treatment with BSA-JRP-HSP NPs. This study has proved that BSA-JRP-HSP NPs can serve as a novel candidate for improving the bioavailability of JRP.

Bovine Serum Albumin Conjugation in Superparamagnetic/Poly(methyl methacrylate) Nanoparticles as an Alternative for Magnetic Enzyme-Linked Immunosorbent Assays

Nanomaterials, such as magnetic nanoparticles have attracted significant attention of medical area due to their capacity to improve the performance of immunoassays. Therefore the aim of this work was to study the bovine serum albumin (BSA) conjugation in superparamagnetic (MNPs)/poly(methyl methacrylate) (PMMA) nanoparticles with further characterization and application in enzyme-linked immunosorbent (ELISA) assay. The successful conjugation of BSA in MNPs- PMMA nanoparticles was confirmed by several techniques, including light scattering, zeta potential, transmission electron microscopy (TEM) and Lowry protein quantification assay. The superparamagnetic properties were confirmed by vibrating sample magnetometer. BSA conjugated MNPs-PMMA nanoparticles presented higher interactions with antibody than free BSA. The BSA + MNPs-PMMA nanoparticles (magnetic ELISA assay) reduced the time and increased the sensibility of traditional ELISA assay, reinforcing the idea that the use these nanomaterials are an excellent alternative for the immunoassays field.

Preparation and characterization of BSA as a model protein loaded chitosan nanoparticles for the development of protein-/peptide-based drug delivery system

Background

The purpose of this study was to develop protein-/peptide-loaded nanoparticle-based delivery system, which can efficiently deliver therapeutic molecules to the lung via pulmonary delivery. The chitosan nanoparticles were prepared by the ionic gelation method, and bovine serum albumin was used as a model protein. These nanoparticles were characterized for size, zeta potential, encapsulation efficiency, cell cytotoxicity, uptake study, release profile and size distribution and uniformity. The chemical interaction of chitosan and protein was studied by XRD and FTIR. The integrity assessment of encapsulated protein into nanoparticle was studied by native and SDS-PAGE gel electrophoresis.

Results

The size and zeta potential of BSA nanoparticles were 193.53 ± 44.97 to 336.36 ± 94.63 and 12.73 ± 0.41 to 18.33 ± 0.96, respectively, with PDI values of 0.35–0.45. The encapsulation efficiency was in the range of 80.73 ± 6.37% to 92.34 ± 1.72%. The cumulative release of the BSA from the nanoparticles was 72.56 ± 6.67% in 2 weeks. The BSA-loaded nanoparticles showed good uptake and no significant cytotoxicity observed into the A549 cell line. In this study, it was also observed that during nanoparticles’ synthesis protein structure and integrity is not compromised. The nanoparticles showed controlled and sustained release with initial burst release. In TEM images, it was shown that nanoparticles’ distribution is uniform within nanometre range.

Conclusion

From this study, it was concluded that nanoparticles prepared by this method are suitable to deliver protein/peptide into the cells without any degradation of protein during process of nanoparticle fabrication.

Utilization of diverse protein sources for the development of protein-based nanostructures as bioactive carrier systems: A review of recent research findings (2010-2021)

Consumer awareness of the relationship between health and nutrition has caused a substantial increase in the demand for nutraceuticals and functional foods containing bioactive compounds (BACs) with potential health benefits. However, the direct incorporation of many BACs into commercial food and beverage products is challenging because of their poor matrix compatibility, chemical instability, low bioavailability, or adverse impact on food quality. Advanced encapsulation technologies are therefore being employed to overcome these problems. In this article, we focus on the utilization of plant and animal derived proteins to fabricate micro and nano-particles that can be used for the oral delivery of BACs such as omega-3 oils, vitamins and nutraceuticals. This review comprehensively discusses different methods being implemented for fabrications of protein-based delivery vehicles, types of proteins used, and their compatibility for the purpose. Finally, some of the challenges and limitations of different protein matrices for encapsulation of BACs are deliberated upon. Various approaches have been developed for the fabrication of protein-based microparticles and nanoparticles, including injection-gelation, controlled denaturation, and antisolvent precipitation methods. These methods can be used to construct particle-based delivery systems with different compositions, sizes, surface hydrophobicity, and electrical characteristics, thereby enabling them to be used in a wide range of applications.

Nanoprecipitation as a simple and straightforward process to create complex polymeric colloidal morphologies

Polymeric nanoparticles are highly important functional nanomaterials for a large range of applications from therapeutics to energy. Advances in nanotechnology have enabled the engineering of multifunctional polymeric nanoparticles with a variety of shapes and inner morphologies. Thanks to its inherent simplicity, the nanoprecipitation technique has progressively become a popular approach to construct polymeric nanoparticles with precise control of nanostructure. The present review highlights the great capability of this technique in controlling the fabrication of various polymeric nanostructures of interest. In particular, we show here how the nanoprecipitation of either block copolymers or mixtures of homopolymers can afford a myriad of colloids displaying equilibrium (typically onion-like) or out-of-equilibrium (stacked lamellae, porous cores) morphologies, depending whether the system "freezes" while passing the glass transition or crystallization point of starting materials. We also show that core-shell morphologies, either from polymeric or oil/polymer mixtures, are attainable by this one-pot process. A final discussion proposes new directions to enlarge the scope and possible achievements of the process.

Hyaluronic-Coated Albumin Nanoparticles for the Non-Invasive Delivery of Apatinib in Diabetic Retinopathy

Purpose

Apatinib (Apa) is a novel anti-vascular endothelial growth factor with the potential to treat diabetic retinopathy (DR); a serious condition leading to visual impairment and blindness. DR treatment relies on invasive techniques associated with various complications. Investigating topical routes for Apa delivery to the posterior eye segment is thus promising but also challenging due to ocular barriers. Hence, the study objective was to develop Apa-loaded bovine serum albumin nanoparticles (Apa-BSA-NPs) coated with hyaluronic acid (HA); a natural polymer possessing unique mucoadhesive and viscoelastic features with the capacity to actively target CD44 positive retinal cells, for topical administration in DR.

Methods

Apa-BSA-NPs were prepared by desolvation using glutaraldehyde for cross-linking. HA-coated BSA-NPs were also prepared and HA: NPs ratio optimized. Nanoparticles were characterized for colloidal properties, entrapment efficiency (EE%), in vitro drug release and mucoadhesive potential. In vitro cytotoxicity on rabbit corneal epithelial cells (RCE) was assessed using MTT assay, while efficacy was evaluated in vivo in a diabetic rat model by histopathological examination of the retina by light and transmission electron microscopy. Retinal accumulation of fluorescently labeled BSA-NP and HA-BSA-NP was assessed using confocal microscope scanning.

Results

Apa-HA-BSA-NPs prepared under optimal conditions showed size, PdI and zeta potential: 222.2±3.56 nm, 0.221±0.02 and -37.3±1.8 mV, respectively. High EE% (69±1%), biphasic sustained release profile with an initial burst effect and mucoadhesion was attained. No evidence of cytotoxicity was observed on RCE cells. In vivo histopathological studies on DR rat model revealed alleviated retinal micro- and ultrastructural changes in the topical HA-Apa-BSA-NP treated eyes with normal basement membrane and retinal thickness comparable to normal control and intravitreally injected nanoparticles. Improved retinal accumulation for HA-BSA-NP was also observed by confocal microscopy.

Conclusion

Findings present HA-Apa-BSA-NPs as a platform for enhanced topical therapy of DR overcoming the devastating ocular complications of the intravitreal route.

Aryl N-[ω-(6-Fluoroindol-1-yl)alkyl]carbamates as Inhibitors of Fatty Acid Amide Hydrolase, Monoacylglycerol Lipase, and Butyrylcholinesterase: Structure-Activity Relationships and Hydrolytic Stability

A series of aryl N-[ω-(6-fluoroindol-1-yl)alkyl]carbamates with alkyl spacers of varying lengths between the indole and the carbamate group and with differently substituted aryl moieties at the carbamate oxygen were synthesized and tested for inhibition of the pharmacologically interesting serine hydrolases fatty acid amide hydrolase (FAAH), monoacylglycerol lipase (MAGL), butyrylcholinesterase (BuChE), and acetylcholinesterase (AChE). Furthermore, the chemical stability in an aqueous solution and the metabolic stability toward esterases in porcine liver homogenate and porcine blood plasma were determined. While most of the synthesized derivatives were potent inhibitors of FAAH, a considerable inhibition of MAGL and BuChE was elicited only by compounds with a high carbamate reactivity, as evidenced by a significant hydrolysis of these compounds in an aqueous solution. However, the high inhibitory potency of some compounds toward MAGL and BuChE, especially that of the ortho-carboxyphenyl derivative 37, could not be explained by chemical reactivity alone. Several of the carbamates studied possessed varying degrees of stability toward esterases from liver and blood plasma. In some cases, marked inactivation by the pseudo-esterase activity of plasma albumin was observed. Mass spectrometric studies showed that such carbamates formed covalent bonds with albumin at several sites.

Nanoparticles as a Tool for Broadening Antifungal Activities

Fungal infections are diseases that are considered neglected although their infection rates have increased worldwide in the last decades. Thus, since the antifungal arsenal is restricted and many strains have shown resistance, new therapeutic alternatives are necessary. Nanoparticles are considered important alternatives to promote drug delivery. In this sense, the objective of the present study was to evaluate the contributions of newly developed nanoparticles to the treatment of fungal infections. Studies have shown that nanoparticles generally improve the biopharmaceutical and pharmacokinetic characteristics of antifungals, which is reflected in a greater pharmacodynamic potential and lower toxicity, as well as the possibility of prolonged action. It also offers the proposition of new routes of administration. Nanotechnology is known to contribute to a new drug delivery system, not only for the control of infectious diseases but for various other diseases as well. In recent years, several studies have emphasized its application in infectious diseases, presenting better alternatives for the treatment of fungal infections.

ROS-Mediated Apoptosis Induced by BSA Nanospheres Encapsulated with Fruit Extract of Cucumis prophetarum in Various Human Cancer Cell Lines

In recent decades, biodegradable polymeric nanoparticles have been used as a nanocarrier for the delivery of anticancer drugs. In the present study, we synthesize bovine serum albumin (BSA) nanospheres and evaluate their ability to incorporate a plant extract with anticancer activity. The plant extract used was the methanol fruit extract of Cucumis prophetarum, which is a medicinal herb. The fruit-extract-encapsulated BSA nanospheres (Cp-BSA nanospheres) were prepared using a desolvation method at various pH values of 5, 7, and 9. The nanosphere formulations were characterized using various techniques such as dynamic light scattering (DLS), ζ-potential, Fourier transform infrared spectroscopy (FTIR), and field-effect scanning electron microscopy (FESEM). The results show that the Cp-BSA nanospheres prepared at pH 7 were spherical with a uniform particle size, low polydispersity index (PDI), ζ-potential, and high entrapment efficiency (82.3%) and showed sustained release of fruit extract from Cp-BSA nanospheres in phosphate-buffered saline (PBS), pH 5. The anticancer activity was evaluated on A549, HepG2, MCF-7 cancer cell lines and HEK 293 normal cell lines. In vitro, antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, intracellular reactive oxygen species (ROS) production, and mitochondrial membrane potential were estimated. An in vitro cellular uptake study was performed using fluorescein isothiocyanate (FITC) dye at a different time of incubation, and DNA fragmentation was observed in a dose-dependent manner. The gene expression level of Bax and the suppression level of Bcl-2 were observed upon the treatment of Cp-BSA nanospheres. Thus, the Cp-BSA nanospheres triggered ROS-dependent mitochondrial apoptosis in different human cancer cell lines when compared to the noncancerous cell lines and could be used as a potential candidate for anticancer agents.

Development of polyoxyethylene (2) oleyl ether-gliadin nanoparticles: Characterization and in vitro cytotoxicity

Natural polymers have been widely investigated as materials for the delivery of active compounds as a consequence of their biocompatibility, low-cost and the opportunity they furnish to obtain micro- and nanostructures. In this investigation, commercial wheat gliadin was used as raw material with the aim of obtaining a vegetal protein-based nanoformulation to be used for various applications. The influence of non-ionic and anionic surfactants on the physico-chemical properties of gliadin nanoparticles was evaluated in order to propose a suitable candidate able to stabilize the colloidal structure. The use of Super Refined polyoxyethylene (2) oleyl ether gave the best results, promoting the formation of spherical-shaped nanosystems with a narrow size distribution. The oleyl ether-based emulsifier prevented the destabilization of the colloidal systems when pH- and temperature-dependent stress was applied. A freeze-dried formulation was obtained when mannose was used as a cryoprotectant. Polyoxyethylene (2) oleyl ether-stabilized nanosystems were shown to retain and release both hydrophilic and lipophilic model compounds in a controlled manner. The cytotoxicity of the surfactant-free and polyoxyethylene (2) oleyl ether-stabilized gliadin based nanosystems was assessed on human cells, both normal and tumoural, in order to investigate the concentrations of particles that can be used during in vitro experiments. Polyoxyethylene (2) oleyl ether-stabilized gliadin-based nanosystems are promising carriers for the delivery of several active compounds.

Screening of critical variables in fabricating polycaprolactone nanoparticles using Neuro Fuzzy Logic

In this work, we used the artificial intelligence tool known as neurofuzzy logic (NFL) for fabricating uniform nanoparticles of polycaprolactone by the nanoprecipitation method with a focus on stabilizer selection. The adaptability of NFL assisted the decision-making on different manufacturing and formulation conditions. The nanoprecipitation method can be summarized as mixing a poorly water-soluble polymer solution with water and its consequent precipitation. Although nanoprecipitation seems simple, the process is highly variable to even slight modifications, leading to polydispersity and nanoparticle aggregation. Here, the NFL model established relationships between mixing conditions, different stabilizers and solvents, among other parameters. Seven parameters measured by dynamic light scattering and laser doppler electrophoresis were modelized with high predictability using NFL tool, as a function of the raw materials and operation conditions. The model allowed the principal component analysis to be carried out, showing that the selection of a stabilizer is the most critical parameter for avoiding nanoparticle aggregation. Then, inputs related to fluid dynamics were relevant to tune the characteristics of the stabilized nanoparticles even further. NFL model showed great potential to support pharmaceutical research by finding subtle relationships between several variables, even from incomplete or fragmented data, which is common in pharmaceutical development.

Post-synthesis nanostructuration of BSA-Capsaicin nanoparticles generated by sucrose excipient

In the pharmaceutical industry nano-hydrocolloid systems frequently coalesce or present nanoparticle aggregation after a long storage periods. Besides, the lyophilization process used to dry nanoparticles (NPs) produces loss of their original properties after dispersion. In this work we evaluated the effect on morphology and physicochemical properties of different protective excipients during drying of bovine serum albumin (BSA) NPs loaded with different concentrations of capsaicin. Capsaicin concentrations of 0, 812, 1625, 2437, and 3250 µg mL⁻¹ were used; subsequently, NPs were dried with deionized water (DW), NaCl (DN), sucrose (DS), and not dried (ND). We found that ND, DW, and DN treatments showed a negative effect on the NPs properties; while, DS reduced the aggregation and produced the formation of isolated nanoparticles at higher concentrations of capsaicin (3250 µg mL⁻¹), improving their circular shape, morphometrical parameters, and ζ-potential. The stability of the BSA-capsaicin NPs was associated to complex capsaicin/amino acid/water, in which GLY/GLN, ALA/HIS, ARG, THR, TYR, and Iso/CYS amino acids are involved in the restructuration of capsaicin molecules into the surface of nanoparticles during the drying process. The secondary nanostructuration in the post-synthesis stage can improve the molecular stability of the particles and the capacity of entrapping hydrophobic drugs, like capsaicin.

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.