Molecular interaction of proteins and peptides with nanoparticles

Unlocking nature's arsenal: Nanotechnology for targeted delivery of venom toxins in cancer therapy

AIM

The aim of the present review is to shed light on the nanotechnological approaches adopted to overcome the shortcomings associated with the delivery of venom peptides which possess inherent anti-cancer properties.

BACKGROUND

Venom peptides although have been reported to demonstrate anti-cancer effects, they suffer from several disadvantages such as in vivo instability, off-target adverse effects, limited drug loading and low bioavailability. This review presents a comprehensive compilation of different classes of nanocarriers while underscoring their advantages, disadvantages and potential to carry such peptide molecules for in vivo delivery. It also discusses various nanotechnological aspects such as methods of fabrication, analytical tools to assess these nanoparticulate formulations, modulation of nanocarrier polymer properties to enhance loading capacity, stability and improve their suitability to carry toxic peptide drugs.

CONCLUSION

Nanotechnological approaches bear great potential in delivering venom peptide-based molecules as anticancer agents by enhancing their bioavailability, stability, efficacy as well as offering a spatiotemporal delivery approach. However, the challenges associated with toxicity and biocompatibility of nanocarriers must be duly addressed.

PERSPECTIVES

The everlasting quest for new breakthroughs for safer delivery of venom peptides in human subjects is fuelled by unmet clinical needs in the current landscape of chemotherapy. In addition, exhaustive efforts are required in obtaining and purifying the venom peptides followed by designing and optimizing scale up technologies.

A comprehensive investigation of the interactions of human serum albumin with polymeric and hybrid nanoparticles

Nanoparticles (NPs) engineered as drug delivery systems continue to make breakthroughs as they offer numerous advantages over free therapeutics. However, the poor understanding of the interplay between the NPs and biomolecules, especially blood proteins, obstructs NP translation to clinics. Nano-bio interactions determine the NPs' in vivo fate, efficacy and immunotoxicity, potentially altering protein function. To fulfill the growing need to investigate nano-bio interactions, this study provides a systematic understanding of two key aspects: (i) protein corona (PC) formation and (ii) NP-induced modifications on protein's structure and stability. A methodology was developed by combining orthogonal techniques to analyze both quantitative and qualitative aspects of nano-bio interactions, using human serum albumin (HSA) as a model protein. Protein quantification via liquid chromatography-mass spectrometry, and capillary zone electrophoresis (CZE) clarified adsorbed protein quantity and stability. CZE further unveiled qualitative insights into HSA forms (native, glycated HSA and cysteinylated), while synchrotron radiation circular dichroism enabled analyzing HSA's secondary structure and thermal stability. Comparative investigations of NP cores (organic vs. hybrid), and shells (with or without polyethylene glycol (PEG)) revealed pivotal factors influencing nano-bio interactions. Polymeric NPs based on poly(lactic-co-glycolic acid) (PLGA) and hybrid NPs based on metal-organic frameworks (nanoMOFs) presented distinct HSA adsorption profiles. PLGA NPs had protein-repelling properties while inducing structural modifications on HSA. In contrast, HSA exhibited a high affinity for nanoMOFs forming a PC altering thereby the protein structure. A shielding effect was gained through PEGylation for both types of NPs, avoiding the PC formation as well as the alteration of unbound HSA structure.

Natural compounds-based nanomedicines for cancer treatment: Future directions and challenges

Several efforts have been extensively accomplished for the amelioration of the cancer treatments using different types of new drugs and less invasives therapies in comparison with the traditional therapeutic modalities, which are widely associated with numerous drawbacks, such as drug resistance, non-selectivity and high costs, restraining their clinical response. The application of natural compounds for the prevention and treatment of different cancer cells has attracted significant attention from the pharmaceuticals and scientific communities over the past decades. Although the use of nanotechnology in cancer therapy is still in the preliminary stages, the application of nanotherapeutics has demonstrated to decrease the various limitations related to the use of natural compounds, such as physical/chemical instability, poor aqueous solubility, and low bioavailability. Despite the nanotechnology has emerged as a promise to improve the bioavailability of the natural compounds, there are still limited clinical trials performed for their application with various challenges required for the pre-clinical and clinical trials, such as production at an industrial level, assurance of nanotherapeutics long-term stability, physiological barriers and safety and regulatory issues. This review highlights the most recent advances in the nanocarriers for natural compounds secreted from plants, bacteria, fungi, and marine organisms, as well as their role on cell signaling pathways for anticancer treatments. Additionally, the clinical status and the main challenges regarding the natural compounds loaded in nanocarriers for clinical applications were also discussed.

Protein Binding Leads to Reduced Stability and Solvated Disorder in the Polystyrene Nanoparticle Corona

Understanding the conformation of proteins in the nanoparticle corona has important implications in how organisms respond to nanoparticle-based drugs. These proteins coat the nanoparticle surface, and their properties will influence the nanoparticle's interaction with cell targets and the immune system. While some coronas are thought to be disordered, two key unanswered questions are the degree of disorder and solvent accessibility. Here, a model is developed for protein corona disorder in polystyrene nanoparticles of varying size. For two different proteins, it is found that binding affinity decreases as nanoparticle size increases. The stoichiometry of binding, along with changes in the hydrodynamic size, supports a highly solvated, disordered protein corona anchored at a small number of attachment sites. The scaling of the stoichiometry versus nanoparticle size is consistent with disordered polymer dimensions. Moreover, it is found that proteins are destabilized less in the presence of larger nanoparticles, and hydrophobic exposure decreases at lower curvatures. The observations hold for proteins on flat polystyrene surfaces, which have the lowest hydrophobic exposure. The model provides an explanation for previous observations of increased amyloid fibrillation rates in the presence of larger nanoparticles, and it may rationalize how cell receptors can recognize protein disorder in therapeutic nanoparticles.

Human Serum Albumin in the Presence of Small Platinum Nanoparticles

Noble metal materials, especially platinum nanoparticles (Pt NPs), have immense potential in nanomedicine as therapeutic agents on account of their high electron density and their high surface area. Intravenous injection is proposed as the best mode to deliver the product to patients. However, our understanding of the reaction of nanoparticles with blood components, especially proteins, is far behind the explosive development of these agents. Using synchrotron radiation circular dichroism (SRCD), we investigated the structural and stability changes of human serum albumin (HSA) upon interaction with PEG-OH coated Pt NPs at nanomolar concentrations, conditions potentially encountered for intravenous injection. There is no strong complexation found between HSA and Pt NPs. However, for the highest molar ratio of NP:HSA of 1:1, an increase of 18 °C in the thermal unfolding of HSA was observed, which is attributed to increased thermal stability of HSA generated by preferential hydration. This work proposes a new and fast method to probe the potential toxicity of nanoparticles intended for clinical use with intravenous injection.

Tackling breast cancer with gold nanoparticles: twinning synthesis and particle engineering with efficacy

The World Health Organization identifies breast cancer as the most prevalent cancer despite predominantly affecting women. Surgery, hormonal therapy, chemotherapy, and radiation therapy are the current treatment modalities. Site-directed nanotherapeutics, engineered with multidimensional functionality are now the frontrunners in breast cancer diagnosis and treatment. Gold nanoparticles with their unique colloidal, optical, quantum, magnetic, mechanical, and electrical properties have become the most valuable weapon in this arsenal. Their advantages include facile modulation of shape and size, a high degree of reproducibility and stability, biocompatibility, and ease of particle engineering to induce multifunctionality. Additionally, the surface plasmon oscillation and high atomic number of gold provide distinct advantages for tailor-made diagnosis, therapy or theranostic applications in breast cancer such as photothermal therapy, radiotherapy, molecular labeling, imaging, and sensing. Although pre-clinical and clinical data are promising for nano-dimensional gold, their clinical translation is hampered by toxicity signs in major organs like the liver, kidneys and spleen. This has instigated global scientific brainstorming to explore feasible particle synthesis and engineering techniques to simultaneously improve the efficacy and versatility and widen the safety window of gold nanoparticles. The present work marks the first study on gold nanoparticle design and maneuvering techniques, elucidating their impact on the pharmacodynamics character and providing a clear-cut scientific roadmap for their fast-track entry into clinical practice.

Different functional groups of carbon dots influence the formation of protein crowns and pepsin characteristic in vitro digestion

Application of nanomaterials (NMs) in agriculture poses an ingestion risk to humans and may affect the digestive process. Different fates of NMs with differential charges in the gastrointestinal tract should be considered. In this study, the interaction between three carbon dots (CDs) carried with different functional groups (-NH2, -OH, and -COOH) and pepsin was analyzed through an in vitro digestion model. The results showed that CDs significantly reduced pepsin activity. Among them, CDs-NH2 had the greatest effect, following by CDs-OH, and CDs-COOH. Besides, molecular docking demonstrated the specific binding site of CDs to pepsin, while the most stable binding energy (-8.10 kcal/mol) was formed between CDs-NH2 and pepsin. Further, CDs formed a nanomaterial-protein crown structure with pepsin. The present study enriches the functional group properties of CDs in the digestion and provides new ideas for the potential human health of NMs.

Unveiling the challenges of engineered protein corona from the proteins' perspective

It is well known that protein corona affects the "biological identity" of nanoparticles (NPs), which has been seen as both a challenge and an opportunity. Approaches have moved from avoiding protein adsorption to trying to direct it, taking advantage of the formation of a protein corona to favorably modify the pharmacokinetic parameters of NPs. Although promising, the results obtained with engineered NPs still need to be completely understood. While much effort has been put into understanding how the surface of nanomaterials affects protein absorption, less is known about how proteins can affect corona formation due to their specific physicochemical properties. This review addresses this knowledge gap, examining key protein factors influencing corona formation, highlighting current challenges in studying protein-protein interactions, and discussing future perspectives in the field.

Surface Chemistry of Biologically Active Reducible Oxide Nanozymes

Reducible metal oxide nanozymes (rNZs) are a subject of intense recent interest due to their catalytic nature, ease of synthesis, and complex surface character. Such materials contain surface sites which facilitate enzyme-mimetic reactions via substrate coordination and redox cycling. Further, these surface reactive sites are shown to be highly sensitive to stresses within the nanomaterial lattice, the physicochemical environment, and to processing conditions occurring as part of their syntheses. When administered in vivo, a complex protein corona binds to the surface, redefining its biological identity and subsequent interactions within the biological system. Catalytic activities of rNZs each deliver a differing impact on protein corona formation, its composition, and in turn, their recognition, and internalization by host cells. Improving the understanding of the precise principles that dominate rNZ surface-biomolecule adsorption raises the question of whether designer rNZs can be engineered to prevent corona formation, or indeed to produce "custom" protein coronas applied either in vitro, and preadministration, or formed immediately upon their exposure to body fluids. Here, fundamental surface chemistry processes and their implications in rNZ material performance are considered. In particular, material structures which inform component adsorption from the application environment, including substrates for enzyme-mimetic reactions are discussed.

Advanced Thermoelectric Textiles for Power Generation: Principles, Design, and Manufacturing

Self-powered wearable thermoelectric (TE) devices significantly reduce the inconvenience caused to users, especially in daily use of portable devices and monitoring personal health. The textile-based TE devices (TETs) exhibit the excellent flexibility, deformability, and light weight, which fulfill demands of long-term wearing for the human body. In comparison to traditional TE devices with their longstanding research history, TETs are still in an initial stage of growth. In recent years, TETs to provide electricity for low-power wearable electronics have attracted increasing attention. This review summarizes the recent progress of TETs from the points of selecting TE materials, scalable fabrication methods of TE fibers/yarns and TETs, structure design of TETs and reported high-performance TETs. The key points to develop TETs with outstanding TE properties and mechanical performance and better than available optimization strategies are discussed. Furthermore, remaining challenges and perspectives of TETs are also proposed to suggest practical applications for heat harvesting from human body.

Biopolymers as promising vehicles for drug delivery to the brain

The brain is a privileged organ, tightly guarded by a network of endothelial cells, pericytes, and glial cells called the blood brain barrier. This barrier facilitates tight regulation of the transport of molecules, ions, and cells from the blood to the brain. While this feature ensures protection to the brain, it also presents a challenge for drug delivery for brain diseases. It is, therefore, crucial to identify molecules and/or vehicles that carry drugs, cross the blood brain barrier, and reach targets within the central nervous system. Biopolymers are large polymeric molecules obtained from biological sources. In comparison with synthetic polymers, biopolymers are structurally more complex and their 3D architecture makes them biologically active. Researchers are therefore investigating biopolymers as safe and efficient carriers of brain-targeted therapeutic agents. In this article, we bring together various approaches toward achieving this objective with a note on the prospects for biopolymer-based neurotherapeutic/neurorestorative/neuroprotective interventions. Finally, as a representative paradigm, we discuss the potential use of nanocarrier biopolymers in targeting protein aggregation diseases.

Antimicrobial Antioxidant Polymer Films with Green Silver Nanoparticles from Symphyti radix

Antimicrobial natural polymer film with silver nanoparticles (AgNPs) biosynthesized using aqueous plant root extracts as reducing capping agents and for film formatting show extensive applicability for pathogenic microorganism problems. The formation of AgNPs was confirmed by transmission electron microscopy (TEM) and scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) techniques. The antimicrobial activity of biofilm with green AgNPs was analysed by inhibiting the growth of Gram-negative and Gram-positive bacteria culture using the Kirby-Bauer disk diffusion susceptibility test. Total phenolic content and antioxidant activity were slightly higher in aqueous extracts of Sym. Radix than in Sym. Radix/AgNPs. The antimicrobial effect of polymer film/AgNPs against selected test bacteria cultures was substantially more robust than with pure film. Pictures of AgNPs obtained by TEM revealed the presence of spherical-shaped nano-objects with an average size 27.45 nm. SEM-EDS studies confirmed the uniform distribution of metal nanoparticles throughout the biopolymeric matrix. Morphological studies of the surface showed that the obtained surface of the films was even, without holes or other relief irregularities. These apparent Symphyti radix polymer film/AgNPs' biological functions could provide a platform for fighting pathogenic bacteria in the era of multi-drug resistance.

Interaction of gallium, indium, and vanadyl curcumin complexes with hen egg-white lysozyme (HEWL): Mechanistic aspects and evaluation of antiamyloidogenic activity

Many proteins and peptides can aggregate into amyloid fibrils with high-ordered and cross-β rich structure characteristics. Amyloid deposition is a common feature of neurodegenerative diseases called amyloidosis. Various natural polyphenolic compounds such as curcumin exhibited antiamyloidogenic activities, but less researches were focused on the metal complexes of these compounds. In this study, the inhibitory effects of gallium curcumin (Ga(cur)3), indium curcumin (In(cur)3), and vanadyl curcumin (VO(cur)2) on the amyloid fibrillation of hen egg white lysozyme (HEWL) have been investigated. Moreover, the details of binding interactions of these metal complexes with HEWL have been explored. The results of fluorescence quenching analyses revealed that In(cur)3 and VO(cur)2 have much higher binding affinities than Ga(cur)3 toward HEWL. The interactions of these metal complexes were accompanied by partial conformational changes in the tertiary structure of HEWL. The kinetic curves of the fibrillation process demonstrated that In(cur)3 and VO(cur)2 have higher inhibitory effects than Ga(cur)3 on the amyloid fibrillation of HEWL. The strength of binding to HEWL is completely in accordance with inhibitory activities of these metal complexes of curcumin.

pH-Dependent HEWL-AuNPs Interactions: Optical Study

Optical methods (spectroscopy, spectrofluorometry, dynamic light scattering, and refractometry) were used to study the change in the state of hen egg-white lysozyme (HEWL), protein molecules, and gold nanoparticles (AuNPs) in aqueous colloids with changes in pH, and the interaction of protein molecules with nanoparticles was also studied. It was shown that changing pH may be the easiest way to control the protein corona on gold nanoparticles. In a colloid of nanoparticles, both in the presence and absence of protein, aggregation-deaggregation, and in a protein colloid, monomerization-dimerization-aggregation are the main processes when pH is changed. A specific point at pH 7.5, where a transition of the colloidal system from one state to another is observed, has been found using all the optical methods mentioned. It has been shown that gold nanoparticles can stabilize HEWL protein molecules at alkaline pH while maintaining enzymatic activity, which can be used in practice. The data obtained in this manuscript allow for the state of HEWL colloids and gold nanoparticles to be monitored using one or two simple and accessible optical methods.

Immobilization of azide-functionalized proteins to micro- and nanoparticles directly from cell lysate

Immobilization of proteins and enzymes on solid supports has been utilized in a variety of applications, from improved protein stability on supported catalysts in industrial processes to fabrication of biosensors, biochips, and microdevices. A critical requirement for these applications is facile yet stable covalent conjugation between the immobilized and fully active protein and the solid support to produce stable, highly bio-active conjugates. Here, we report functionalization of solid surfaces (gold nanoparticles and magnetic beads) with bio-active proteins using site-specific and biorthogonal labeling and azide-alkyne cycloaddition, a click chemistry. Specifically, we recombinantly express and selectively label calcium-dependent proteins, calmodulin and calcineurin, and cAMP-dependent protein kinase A (PKA) with N-terminal azide-tags for efficient conjugation to nanoparticles and magnetic beads. We successfully immobilized the proteins on to the solid supports directly from the cell lysate with click chemistry, forgoing the step of purification. This approach is optimized to yield low particle aggregation and high levels of protein activity post-conjugation. The entire process enables streamlined workflows for bioconjugation and highly active conjugated proteins.

Morphological and lipid metabolism alterations in macrophages exposed to model environmental nanoplastics traced by high-resolution synchrotron techniques

The release of nanoplastics (NPs) in the environment is a significant health concern for long-term exposed humans. Although their usage has certainly revolutionized several application fields, at nanometer size, NPs can easily interact at the cellular level, resulting in potential harmful effects. Micro/Nanoplastics (M/NPs) have a demonstrated impact on mammalian endocrine components, such as the thyroid, adrenal gland, testes, and ovaries, while more investigations on prenatal and postnatal exposure are urgently required. The number of literature studies on the NPs' presence in biological samples is increasing. However, only a few offer a close study on the model environmental NP-immune system interaction exploited by advanced microscopy techniques. The present study highlights substantial morphological and lipid metabolism alterations in human M1 macrophages exposed to labeled polypropylene and polyvinyl chloride nanoparticles (PP and PVC NPs) (20 μg/ml). The results are interpreted by advanced microscopy techniques combined with standard laboratory tests and fluorescence microscopy. We report the accurate detection of polymeric nanoparticles doped with cadmium selenide quantum dots (CdSe-QDs NPs) by following the Se (L line) X-ray fluorescence emission peak at higher sub-cellular resolution, compared to the supportive light fluorescence microscopy. In addition, scanning transmission X-ray microscopy (STXM) imaging successfully revealed morphological changes in NP-exposed macrophages, providing input for Fourier transform infrared (FTIR) spectroscopy analyses, which underlined the chemical modifications in macromolecular components, specifically in lipid response. The present evidence was confirmed by quantifying the lipid droplet (LD) contents in PP and PVC NPs-exposed macrophages (0-100 μg/ml) by Oil Red O staining. Hence, even at experimental NPs' concentrations and incubation time, they do not significantly affect cell viability; they cause an evident lipid metabolism impairment, a hallmark of phagocytosis and oxidative stress.

Protein Binding Leads to Reduced Stability and Solvated Disorder in the Polystyrene Nanoparticle Corona

Understanding the conformation of proteins in the nanoparticle corona has important implications in how organisms respond to nanoparticle-based drugs. These proteins coat the nanoparticle surface, and their properties will influence the nanoparticle's interaction with cell targets and the immune system. While some coronas are thought to be disordered, two key unanswered questions are the degree of disorder and solvent accessibility. Here, using a comprehensive thermodynamic approach, along with supporting spectroscopic experiments, we develop a model for protein corona disorder in polystyrene nanoparticles of varying size. For two different proteins, we find that binding affinity decreases as nanoparticle size increases. The stoichiometry of binding, along with changes in the hydrodynamic size, support a highly solvated, disordered protein corona anchored at a small number of enthalpically-driven attachment sites. The scaling of the stoichiometry vs. nanoparticle size is consistent disordered polymer dimensions. Moreover, we find that proteins are destabilized less severely in the presence of larger nanoparticles, and this is supported by measurements of hydrophobic exposure, which becomes less pronounced at lower curvatures. Our observations hold for flat polystyrene surfaces, which, when controlled for total surface area, have the lowest hydrophobic exposure of all systems. Our model provides an explanation for previous observations of increased amyloid fibrillation rates in the presence of larger nanoparticles, and it may rationalize how cell receptors can recognize protein disorder in therapeutic nanoparticles.

Energies Exploration for the Troponine Molecule Supported on Carbon Nanomaterials: DFT Study

Density functional theory calculations have been used to elucidate structural parameters of pristine cardiac Troponin I and its interaction with carbon nanomaterials. In this case, zigzag single-walled carbon nanotubes and graphene sheets were selected. Troponin I interacted horizontally (leusine terminal) and vertically (lysine terminal) with the nanomaterials. Cohesion and binding energies, band gaps, and charge transfer for the systems were obtained. Cohesion for troponin I supported on graphene and single-walled carbon nanotube in the horizontal position was found to be the most viable system. Binding for the interaction between troponin I and a nanotube in the horizontal position was found to be the most stable with a value of 0.002 eV that increases to 0.004 eV with a van der Waals correction. Furthermore, the density of states exhibits an improvement in band gap for graphene sheets, and finally, a higher charge transfer was reported for troponin I in its horizontal form supported on a zigzag single-walled carbon nanotube.

Nanoparticle protein corona: from structure and function to therapeutic targeting

Nanoparticle (NP)-based therapeutics have ushered in a new era in translational medicine. However, despite the clinical success of NP technology, it is not well-understood how NPs fundamentally change in biological environments. When introduced into physiological fluids, NPs are coated by proteins, forming a protein corona (PC). The PC has the potential to endow NPs with a new identity and alter their bioactivity, stability, and destination. Additionally, the conformation of proteins is sensitive to their physical and chemical surroundings. Therefore, biological factors and protein-NP-interactions can induce changes in the conformation and orientation of proteins in vivo. Since the function of a protein is closely connected to its folded structure, slight differences in the surrounding environment as well as the surface characteristics of the NP materials may cause proteins to lose or gain a function. As a result, this can alter the downstream functionality of the NPs. This review introduces the main biological factors affecting the conformation of proteins associated with the PC. Then, four types of NPs with extensive utility in biomedical applications are described in greater detail, focusing on the conformation and orientation of adsorbed proteins. This is followed by a discussion on the instances in which the conformation of adsorbed proteins can be leveraged for therapeutic purposes, such as controlling protein conformation in assembled matrices in tissue, as well as controlling the PC conformation for modulating immune responses. The review concludes with a perspective on the remaining challenges and unexplored areas at the interface of PC and NP research.

Biosynthesis of Silver Nanoparticles Using Salvia pratensis L. Aerial Part and Root Extracts: Bioactivity, Biocompatibility, and Catalytic Potential

The aim of this research was the synthesis of silver nanoparticles (SPA- and SPR-AgNPs) using the aqueous extracts of the aerial (SPA) and the root (SPR) parts of the plant Salvia pratensis L., their characterization, reaction condition optimization, and evaluation of their biological and catalytic activity. UV-Vis spectroscopy, X-ray powder diffraction (XRPD), scanning electron microscopy with EDS analysis (SEM/EDS), and dynamic light scattering (DLS) analysis were utilized to characterize the nanoparticles, while Fourier transform infrared (FTIR) spectroscopy was used to detect some functional groups of compounds present in the plant extracts and nanoparticles. The phenolic and flavonoid contents, as well as the antioxidant activity of the extracts, were determined spectrophotometrically. The synthesized nanoparticles showed twice-higher activity in neutralizing 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺) compared with the respective extracts. SPR-AgNPs exhibited strong antimicrobial activity against almost all of the tested bacteria (<0.0039 mg/mL) and fungal strains, especially against the genus Penicillium (<0.0391 mg/mL). Moreover, they were fully biocompatible on all the tested eukaryotic cells, while the hemolysis of erythrocytes was not observed at the highest tested concentration of 150 µg/mL. The catalytic activity of nanoparticles toward Congo Red and 4-nitrophenol was also demonstrated. The obtained results confirm the possibility of the safe application of the synthesized nanoparticles in medicine and as a catalyst in various processes.

Bioinspired Polyethylene Glycol Coatings for Reduced Nanoparticle-Protein Interactions

Nanoparticles (NPs) and other engineered nanomaterials have great potential as nanodrugs or nanomedical devices for biomedical applications. However, the adsorption of proteins in blood circulation or similar physiological fluids can significantly alter the surface properties and therapeutic response induced by most nanomaterials. For example, interaction with proteins can change the bloodstream circulation time and availability of therapeutic NPs or hinder the accumulation in their desired target organs. Proteins can also trigger or prevent agglomeration. By combining experimental and computational approaches, we have developed NPs carrying polyethylene glycol (PEG) polymeric coatings that mimic the surface charge distribution of proteins typically found in blood, which are known to show low aggregation under normal blood conditions. Here, we show that NPs with coatings based on apoferritin or human serum albumin display better antifouling properties and weaker protein interaction compared to similar NPs carrying conventional PEG polymeric coatings.

Nucleotide Interaction with Nanocrystalline Ceria Surface

The adsorption of nucleotides on the surface of nanocrystalline cerium dioxide (pHpzc = 6.3) in NaCl solutions was investigated using multi-batch adsorption experiments over a wide range of pH. The obtained results were interpreted as a formation of outer and inner sphere surface complexes with the participation of phosphate moieties. The Basic Stern surface complexation model was applied to obtain quantitative equilibrium reaction constants.

Site-Specific and Tunable Co-immobilization of Proteins onto Magnetic Nanoparticles via Spy Chemistry

Co-immobilization of multiple proteins onto one nanosupport has large potential in mimicking natural multiprotein complexes and constructing efficient cascade biocatalytic systems. However, control of different proteins regarding their spatial arrangement and loading ratio remains a big challenge, and protein co-immobilization often requires the use of purified proteins. Herein, built upon our recently designed SpyTag-functionalized magnetic nanoparticles (MNPs), we established a modular MNP platform for site-specific, tunable, and cost-effective protein co-immobilization. SpyCatcher-fused enhanced green fluorescent protein (i.e., EGFP-SpyCatcher) and mCherry red fluorescent protein (i.e., RFP-SpyCatcher) were designed and conjugated on MNPs, and the immobilized proteins showed 3-7-fold enhancement in storage stability and greatly improved stability against the freeze-thaw process compared to free proteins. The protein-conjugated MNPs also retained desirable colloidal stability and magnetic responsiveness, enabling facile proteins' recovery. Also, one-pot co-immobilization of the two proteins could be fine-tuned with their feed ratios. In addition, MNPs could selectively and efficiently co-immobilize both SpyCatcher-fused proteins from combined cell lysates without purification, offering a convenient and cost-effective approach for multiprotein immobilization. This MNP platform provides a facile and efficient tool to construct bionano hybrid materials (i.e., protein-based MNPs) and multiprotein systems for a variety of industrial and green chemistry applications.

Green Hydrogel Synthesis: Emphasis on Proteomics and Polymer Particle-Protein Interaction

The field of drug discovery has seen significant progress in recent years. These advances drive the development of new technologies for testing compound's effectiveness, as well as their adverse effects on organs and tissues. As an auxiliary tool for drug discovery, smart biomaterials and biopolymers produced from biodegradable monomers allow the manufacture of multifunctional polymeric devices capable of acting as biosensors, of incorporating bioactives and biomolecules, or even mimicking organs and tissues through self-association and organization between cells and biopolymers. This review discusses in detail the use of natural monomers for the synthesis of hydrogels via green routes. The physical, chemical and morphological characteristics of these polymers are described, in addition to emphasizing polymer-particle-protein interactions and their application in proteomics studies. To highlight the diversity of green synthesis methodologies and the properties of the final hydrogels, applications in the areas of drug delivery, antibody interactions, cancer therapy, imaging and biomarker analysis are also discussed, as well as the use of hydrogels for the discovery of antimicrobial and antiviral peptides with therapeutic potential.

Proteomic evaluation of nanotoxicity in aquatic organisms: A review

The alteration of organisms protein functions by engineered nanoparticles (ENPs) is dependent on the complex interplay between their inherent physicochemical properties (e.g., size, surface coating, shape) and environmental conditions (e.g., pH, organic matter). To date, there is increasing interest on the use of 'omics' approaches, such as proteomics, genomics, and others, to study ENPs-biomolecules interactions in aquatic organisms. However, although proteomics has recently been applied to investigate effects of ENPs and associated mechanisms in aquatic organisms, its use remain limited. Herein, proteomics techniques widely applied to investigate ENPs-protein interactions in aquatic organisms are reviewed. Data demonstrates that 2DE and mass spectrometry and/or their combination, thereof, are the most suitable techniques to elucidate ENPs-protein interactions. Furthermore, current status on ENPs and protein interactions, and possible mechanisms of nanotoxicity with emphasis on those that exert influence at protein expression levels, and key influencing factors on ENPs-proteins interactions are outlined. Most reported studies were done using synthetic media and essay protocols and had wide variability (not standardized); this may consequently limit data application in actual environmental systems. Therefore, there is a need for studies using realistic environmental concentrations of ENPs, and actual environmental matrixes (e.g., surface water) to aid better model development of ENPs-proteins interactions in aquatic systems.

CRISPR/Cas9-based coronal nanostructures for targeted mitochondria single molecule imaging

The biological state at the subcellular level is highly relevant to many diseases, and the monitoring of organelles such as mitochondria is crucial based on this. However, most DNA and protein based nanoprobes used for the detection of mitochondrial RNAs (mitomiRs) lack spatial selectivity, which leads to inefficiencies in probe delivery and signal turn-on. Herein, we constructed a novel DNA nanoprobe named protein delivery nano-corona (PDNC) to improve the delivery efficiency of Cas protein, for spatially selective imaging of mitomiRs in living cells switched on by a CRISPR/Cas system. Combined with a single-molecule counting method, this strategy enables highly sensitive detection of low-abundance mitomiR. Therefore, the strategy in this work opens up new opportunities for cell identification, early clinical diagnosis, and research in biological behaviour at the subcellular level.

Mechanistic insights into the size-dependent effects of nanoparticles on inhibiting and accelerating amyloid fibril formation

The aggregation of peptides into amyloid fibrils has been linked to ageing-related diseases, such as Alzheimer's and type 2 diabetes. Interfaces, particularly those with large nanostructured surfaces, can affect the kinetics of peptide aggregation, which ranges from complete inhibition to strong acceleration. While a number of physiochemical parameters determine interfacial effects, we focus here on the role of nanoparticle (NP) size and curvature. We used thioflavin T (ThT) fluorescence assays to demonstrate the size-dependent effects of NPs on amyloid fibril formation for the peptides Aβ₄₀, NNFGAIL, GNNQQNY and VQIYVK. While 5 nm gold NPs (AuNP-5) retarded or inhibited the aggregation of all peptides except NNFGAIL, larger 20 nm gold NPs (AuNP-20) tended to accelerate or not influence peptide aggregation. Differences in the NP effects for the peptides resulted from the different peptide properties (size, tendency to aggregate) and associated surface binding affinities. Additional dynamic light scattering (DLS), electron microscopy, and atomic force microscopy (AFM) experiments with the Aβ₄₀ peptide confirmed size-dependent NP effects on peptide aggregation, and also suggested a structural influence on the formed fibrils. NPs can serve as a surface for the adsorption of peptide monomers and enable nucleation to oligomers and fibril formation. However, molecular dynamics (MD) simulations showed that peptide oligomers were less stable at smaller NPs. High surface curvatures destabilized prefibrillar structures, which provides a possible explanation for inhibitory effects on fibril growth, provided that peptide-NP surface binding was relevant for fibril formation. These mechanistic insights can support the design of future nanostructured materials.

Albumin-Coated Framework Nucleic Acids as Bionic Delivery System for Triple-Negative Breast Cancer Therapy

Triple-negative breast cancer (TNBC) is a subtype of breast cancer, and it has aggressive and more frequent tissue metastases than other breast cancer subtypes. Because the proliferation of TNBC tumor cells does not depend on estrogen receptor (ER), progesterone receptor (PR), and Erb-B2 receptor tyrosine kinase 2 (HER2) and lacks accurate drug targets, conventional chemotherapy is challenging to be effective, and adverse reactions are severe. At present, the treatment strategy for TNBC generally depends on a combination of surgery, radiotherapy, and chemotherapy. Conventional administration methods have minimal effects on TNBC and cause severe damage to normal tissues. Therefore, it is an urgent task to develop an efficient and practical way of drug delivery and open up a new horizon of targeted therapy for TNBC. In our work, bovine serum albumin (BSA) acted as the protective film to prolong the circulation time of the tetrahedral framework nucleic acid (tFNA) delivery system and resist immune clearance in vivo. tFNA was used as a carrier loaded with DOX and AS1411 aptamers for the targeted treatment of triple-negative breast cancer. Compared with existing approaches, this optimized system exhibits stronger tumor-targeting so that tFNAs can be more concentrated around the tumor tissue, reducing DOX toxicity to other organs. This bionic delivery system exhibited effective tumor growth inhibition in the TNBC mice model, offering the clinical potential to promote the treatment of TNBC with great potential for clinical translation.

Comparative and Selective Interaction of Amino Acid d-Cysteine with Colloidal Gold Nanoparticles in the Presence of a Fluorescent Probe in Aqueous Medium

In this communication, we report the comparative and selective interaction of amino acid d-cysteine (d-Cys) with citrate caped gold nanoparticles (Au NPs) in the presence of a fluorescent dye, rhodamine B (RhB), in aqueous solution. Au NPs of size 27.5 nm could almost fully quench the steady-state fluorescence emission of RhB at their optimum concentrations in the mixed solution. The interactions of d-Cys, l-Cys, all other relevant d- and l-amino acids, neurotransmitters, and other relevant biological compounds with the Au NPs/RhB mixed solution have been explored by monitoring the fluorescence recovery efficiencies from the almost fully quenched state of RhB fluorescence via a simple steady-state spectrofluorometric method. The higher fluorescence recovery for the interaction of d-Cys with the Au NPs/RhB mixed system is accompanied by a distinct color change (red-wine to bluish-black) of the assay medium after the reaction compared to that of all other interfering compounds considered in this work. The sensitivity of this fluorometric response lies in a broad linear range of concentrations of d-Cys and the limit of detection (LOD) is found to be 4.2 nM, which is low compared to many other methods available in the literature. The different degrees of interaction of d-Cys and l-Cys with the Au NPs/RhB mixed sample have been further explored by circular dichroism (CD) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The selective interaction of d-Cys with the proposed Au NPs/RhB mixed system is also found to be correlated with interparticle cross-linking and aggregations of nanoparticles by the analysis of ζ potential and dynamic light scattering (DLS) study, transmission electron microscopy (TEM), atomic force microscopy (AFM), UV-vis absorption spectroscopy etc. The proposed interaction mechanism is further studied with a normal human urine sample to elucidate that the optimized combination of Au NPs and RhB may be realized as an efficient platform for detection of the amino acid d-Cys in a real biosample via a simple fluorometric approach.

Advances in Hybrid Vesicular-based Drug Delivery Systems: Improved Biocompatibility, Targeting, Therapeutic Efficacy and Pharmacokinetics of Anticancer Drugs

Anticancer drugs and diagnostics can be transported in nanoscale vesicles that provide a flexible platform. A hybrid nanoparticle, a nano assembly made up of many types of nanostructures, has the greatest potential to perform these two activities simultaneously. Nanomedicine has shown the promise of vesicular carriers based on lipopolymersomes, lipid peptides, and metallic hybrid nano-vesicle systems. However, there are significant limitations that hinder the clinical implementation of these systems at the commercial scale, such as low productivity, high energy consumption, expensive setup, long process durations, and the current cancer therapies described in this article. Combinatorial hybrid systems can be used to reduce the above limitations. A greater therapeutic index and improved clinical results are possible with hybrid nanovesicular systems, which integrate the benefits of many carriers into a single structure. Due to their unique properties, cell-based drug delivery systems have shown tremendous benefits in the treatment of cancer. Nanoparticles (NPs) can benefit significantly from the properties of erythrocytes and platelets, which are part of the circulatory cells and circulate for a long time. Due to their unique physicochemical properties, nanomaterials play an essential role in cell-based drug delivery. Combining the advantages of different nanomaterials and cell types gives the resulting delivery systems a wide range of desirable properties. NPs are nextgeneration core-shell nanostructures that combine a lipid shell with a polymer core. The fabrication of lipid-polymer hybrid NPs has recently undergone a fundamental shift, moving from a two-step to a one-step technique based on the joint self-assembly of polymers and lipids. Oncologists are particularly interested in this method as a combinatorial drug delivery platform because of its two-in-one structure. This article addresses various preparative methods for the preparation of hybrid nano-vesicular systems. It also discusses the cellular mechanism of hybrid nano-vesicular systems and describes the thorough knowledge of various hybrid vesicular systems.

Direct observation of humic acid-promoted hydrolysis of phytate through stabilizing a conserved catalytic domain in phytase

As a potential phosphorus (P) pool, the enzymatic hydrolysis of organic phosphorus (P_o) is of fundamental importance due to the release of bioavailable inorganic phosphate (P_i) for agronomic P sustainability. However, little is known about the role of soil organic matter (SOM) in the hydrolysis process of phytate by phytase and the subsequent chemical behaviors involving the hydrolysis product (P_i) at different soil interfaces. Here, by using liquid-cell atomic force microscopy (AFM), we present a model system to in situ quantify the nucleation kinetics of phytase-released P_i when precipitating with representative soil multivalent cations (Ca²⁺/Fe³⁺) on typical soil mineral/organic interfaces in the presence/absence of humic acid (HA), which involves complex phytase-interface-HA interactions. We observed that a higher HA concentration resulted in a faster nucleation rate of amorphous calcium/iron phosphate (ACP/AIP) on bare and organically-coated (-OH/-COOH) mica surfaces compared with the HA-free control. Besides, the nucleation rate of ACP/AIP induced by organic interfaces was much more significant than that induced by clay mineral interfaces. By combining enzyme activity/stability experiments and AFM-based PeakForce quantitative nanomechanical mapping (PF-QNM) measurements, we directly quantified the contribution of noncovalent phytase-HA interaction to the increase in enzymatic activity from complex phytase-interface-HA interactions. Furthermore, the direct complexation of phytase-HA resulted in the stabilization of a conserved active catalytic domain (ACD) in phytase through the enhanced formation of both an ordered, stereochemically-favored catalytic domain and an unordered non-catalytic domain, which was revealed by Raman secondary structure determination. The results provide direct insights into how HA regulates the catalytic activity of phytase controlling P_o fates and how soil interfaces determine the behaviors of released P_i to affect its availability, and thereby contribute to P sustainability in soils.

TiO2 with Confined Water Boosts Ultrahigh Selective Enrichment of Phosphorylated Proteins

In the selective enrichment of phosphorylated proteins (PPs) from biological samples, the non-phosphorylated proteins (NPPs) adhered onto enrichment adsorbents due to the hydrophobic interaction, resulting in poor selectivity and low recovery of target PPs. Herein, superhydrophilic TiO₂-coated porous SiO₂ microspheres are prepared and boost remarkable selectivity toward standard PP spiked with 2000 mass-fold NPP interference. The outstanding performance of the superhydrophilic microspheres is attributed to the coordination interaction between TiO₂ and PPs, and the confined water layer generated from superhydrophilicity avoids the irreversible adsorption of NPPs by keeping NPP inner hydrophobic regions in a compact structure, which is verified by single molecule force spectroscopy, circular dichroism, and quartz crystal microbalance. This strategy for enrichment is expected to solve the challenge in proteomics and sheds light on the interactions between biomolecules and superwettability.

Associations between differences in anemia-related blood cell parameters and short-term exposure to ambient particle pollutants in middle-aged and elderly residents in Beijing, China

Anemia is a highly prevalent disease among older populations, with multiple adverse health outcomes, and particles exposure is a potential risk factor for anemia. However, evidence on associations of exposure to particles with small size with anemia-related blood cell parameters levels in the elderly is limited, and the underlying mechanisms are unclear. Based on a panel study in Beijing, we found that in 135 elderly participants, mass concentrations of particle with an aerodynamic diameter ≤ 2.5 μm (PM_2.5), black/elemental carbon (BC/EC, particle size range: 0-2.5 μm), and number concentrations of ultrafine particles (UFPs, particle size range: 5.6-93.1 nm) and accumulated mode particles (Acc, size range: 93.1-560 nm) were significantly associated with levels of red blood cell count (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC). The mean ± SD for PM_2.5, UFPs, Acc, BC, OC, and EC were 69.7 ± 61.1 μg/m³, 12.5 ± 4.3 × 10³/cm³, 1.6 ± 1.2 × 10³/cm³, 3.0 ± 2.0 μg/m³, 8.7 ± 6.7 μg/m³, and 2.1 ± 1.6 μg/m³, respectively. Cotinine (higher than 50 ng/mL) is used as an indicator of smoking exposure. The association between MCHC difference and per interquartile range (IQR) increase in average UFPs concentration 14 d before clinical visits was -0.7% (95% CI: -1.1% to -0.3%). Significant associations of UFPs and Acc exposure with MCHC and MCH levels remain robust after adjustment for other pollutants. Furthermore, 25.2% (95% CI: 7.4% to 64.8%) and 29.8% (95% CI: 5.3% to 214.4%) of the difference in MCHC associated with average UFPs and Acc concentrations 14 d before clinical visits were mediated by the level of tumor necrosis factor α (TNF α), a biomarker of systemic inflammation. Our findings for the first time provide the evidence that short-term UFPs and Acc exposure contributed to the damage of anemia-related blood cell in the elderly, and systemic inflammation was a potential internal mediator.

Silica Nanoparticle Acute Toxicity on Male Rattus norvegicus Domestica: Ethological Behavior, Hematological Disorders, Biochemical Analyses, Hepato-Renal Function, and Antioxidant-Immune Response

With extensive production and various applications of silica nanoparticles (SiNPs), there is a controversy regarding the ecotoxicological impacts of SiNPs. Therefore, the current study was aimed to assess the acute toxicity of silica nanoparticles in male Rattus norvegicus domestica after 24 and 96 h. Hematological, serum biochemical, stress biomarker, and immune-antioxidant parameters were addressed. Chemical composition, crystal structure, and the particle shape and morphology of SiNPs were investigated using XRD, FTIR, BET, UV-Vis, and SEM, while TEM was used to estimate the average size distribution of particles. For the exposure experiment, 48 male rats were divided into four groups (12 rat/group) and gavaged daily with different levels of zero (control), 5, 10, and 20 mg of SiNPs corresponding to zero, 31.25, 62.5, and 125 mg per kg of body weight. Sampling was carried out after 24 and 96 h. Relative to the control group, the exposure to SiNPs induced clear behavioral changes such as inactivity, lethargy, aggressiveness, and screaming. In a dose-dependent manner, the behavior scores recorded the highest values. Pairwise comparisons with the control demonstrated a significant (p < 0.05) decrease in hematological and immunological biomarkers [lysozymes and alternative complement activity (ACH50)] with a concomitant reduction in the antioxidant enzymes [catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD)] in all exposed groups to SiNPs. On the contrary, there was a noticeable increase in biochemical parameters (glucose, cortisol, creatinine, urea, low-density lipoproteins (LDL), high-density lipoproteins (HDL), total protein, and albumin) and hepato-renal indicators, including alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), of all SiNP-exposed groups. It was observed that SiNPs induced acute toxicity, either after 24 h or 96 h, post-exposure of rats to SiNPs evidenced by ethological changes, hepato-renal dysfunction, hyperlipemia, and severe suppression in hematological, protein, stress, and immune-antioxidant biomarkers reflecting an impaired physiological status. The obtained outcomes create a foundation for future research to consider the acute toxicity of nanoparticles to preserve human health and sustain the environment.

Change of Cell Toxicity of Food-Borne Nanoparticles after Forming Protein Coronas with Human Serum Albumin

Nanoparticles (NPs) can form protein coronas with plasma proteins after entering the biological environment due to their surface adsorption ability. In this study, the effects of protein coronas of roast squid food-borne nanoparticles (FNPs) with human serum albumin (HSA) on the HepG-2 and normal rat kidney (NRK) cells were investigated. The hydrodynamic diameters of the HSA and HSA-FNPs were 8 and 13 nm, respectively. The cytotoxicity and cell membrane damage of FNPs to HepG-2 cells increased with the increase of roasting temperature. The presence of 4.78 × 10^-3 mol/L FNPs increased the numbers of cellular necrosis and prolonged the G₂ phase of the cell cycle. The formation of protein coronas of squid FNPs mitigated the autophagy phenomenon by FNPs on HepG-2 cells. Moreover, protein coronas reduced the mitochondrial membrane potential in the HepG-2 and NRK cells and the production of reactive oxygen species caused by FNPs. The abnormal contents of oxidative stress indicators such as glutathione, superoxide dismutase, malondialdehyde, and catalase in HepG-2 and NRK cells induced by FNPs were alleviated due to the presence of HSA. These results suggested that the protein coronas formed by HSA on FNPs mitigated the cytotoxicity compared with the bare FNPs, thus providing insights into the interaction of squid FNPs with HSA.

Revisiting the outstanding questions in cancer nanomedicine with a future outlook

The field of cancer nanomedicine has been fueled by the expectation of mitigating the inefficiencies and life-threatening side effects of conventional chemotherapy. Nanomedicine proposes to utilize the unique nanoscale properties of nanoparticles to address the most pressing questions in cancer treatment and diagnosis. The approval of nano-based products in the 1990s inspired scientific explorations in this direction. However, despite significant progress in the understanding of nanoscale properties, there are only very few success stories in terms of substantial increase in clinical efficacy and overall patient survival. All existing paradigms such as the concept of enhanced permeability and retention (EPR), the stealth effect and immunocompatibility of nanomedicine have been questioned in recent times. In this review we critically examine impediments posed by biological factors to the clinical success of nanomedicine. We put forth current observations on critical outstanding questions in nanomedicine. We also provide the promising side of cancer nanomedicine as we move forward in nanomedicine research. This would provide a future direction for research in nanomedicine and inspire ongoing investigations.

Inhibiting mTTR Aggregation/Fibrillation by a Chaperone-like Hydrophobic Amino Acid-Conjugated SPION

Transthyretin (TTR) aggregation via misfolding of a mutant or wild-type protein leads to systemic or partial amyloidosis (ATTR). Here, we utilized variable biophysical assays to characterize two distinct aggregation pathways for mTTR (a synthesized monomer TTR incapable of association into a tetramer) at pH 4.3 and also pH 7.4 with agitation, referred to as mTTR aggregation and fibrillation, respectively. The findings suggest that early-stage conformational changes termed monomer activation here determine the aggregation pathway, resulting in developing either amorphous aggregates or well-organized fibrils. Less packed partially unfolded monomers consisting of more non-regular secondary structures that were rapidly produced via a mildly acidic condition form amorphous aggregates. Meanwhile, more hydrophobic and packed monomers consisting of rearranged β sheets and increased helical content developed well-organized fibrils. Conjugating superparamagnetic iron oxide nanoparticles (SPIONs) with leucine and glutamine (L-SPIONs and G-SPIONs in order) via a trimethoxysilane linker provided the chance to study the effect of hydrophobic/hydrophilic surfaces on mTTR aggregation. The results indicated a powerful inhibitory effect of hydrophobic L-SPIONs on both mTTR aggregation and fibrillation. Monomer depletion was introduced as the governing mechanism for inhibiting mTTR aggregation, while a chaperone-like property of L-SPIONs by maintaining an mTTR native structure and adsorbing oligomers suppressed the progression of further fibril formation.

Nanomaterial-assisted thread-based isotachophoresis with on-thread solute trapping

This research describes a nanomaterial-assisted TB-ITP setup for the clean-up, preconcentration, and trapping of alkaloids in biological fluids, followed by their on-thread DESI-MS determination.

Gold Nanoparticles Augment N-Terminal Cleavage and Splicing Reactions in Mycobacterium tuberculosis SufB

Protein splicing is a self-catalyzed event where the intervening sequence intein cleaves off, joining the flanking exteins together to generate a functional protein. Attempts have been made to regulate the splicing rate through variations in temperature, pH, and metals. Although metal-regulated protein splicing has been more captivating to researchers, metals were shown to only inhibit splicing reactions that confine their application. This is the first study to show the effect of nanoparticles (NPs) on protein splicing. We found that gold nanoparticles (AuNPs) of various sizes can increase the splicing efficiency by more than 50% and the N-terminal cleavage efficiency by more than 45% in Mycobacterium tuberculosis SufB precursor protein. This study provides an effective strategy for engineering splicing-enhanced intein platforms. UV-vis absorption spectroscopy, isothermal titration calorimetry (ITC), and transmission electron microscopy (TEM) confirmed AuNP interaction with the native protein. Quantum mechanics/molecular mechanics (QM/MM) analysis suggested a significant reduction in the energy barrier at the N-terminal cleavage site in the presence of gold atom, strengthening our experimental evidence on heightened the N-terminal cleavage reaction. The encouraging observation of enhanced N-terminal cleavage and splicing reaction can have potential implementations from developing a rapid drug delivery system to designing a contemporary protein purification system.

Quantitative analysis and degradation mechanisms of different protein degradation methods

The abrasive debris produced by wear test of artificial joints in vitro is encapsulated by proteins in serum lubricants, which hinder the characterization of debris analysis. One of the key issues of isolating wear debris from serum is degrading the proteins wrapping the wear debris. In this article, the proteins in calf serum were degraded by a strong alkali, a strong acid, and an enzyme. The residual concentration of proteins in calf serum was detected by UV absorption. Quantitative analysis of protein degradation and the protein degradation rate was proposed, following treatment with different degradation reagents and different incubation times. The results showed that when 10 mL of 25% volume calf serum was added with 40 mL of NaOH and incubated at 65°C for 24 h, the protein degradation rate reached a maximum of 95.52%. The protein degradation rate in the solution ranged from 31.86% to 71.64% when a different volume of 37% HCl was added and incubated at 60°C. The highest protein degradation rate was 94.98% in the protease degradation solution. When the protein degradation rate is less than 70%, the particles were coated by protein. When the protein degradation rate was more than 95%, there was no protein coating around the particles. The three protein degradation methods have different processes and protein degradation rates. A suitable method for protein degradation can be selected according to these practical applications.

Photothermal Regenerated Fibers with Enhanced Toughness: Silk Fibroin/MoS2 Nanoparticles

The distinctive mechanical and photothermal properties of Molybdenum sulfide (MoS2) have the potential for improving the functionality and utilization of silk products in various sectors. This paper reports on the preparation of regenerated silk fibroin/molybdenum disulfide (RSF/MoS2) nanoparticles hybrid fiber with different MoS2 nanoparticles contents by wet spinning. The simulated sunlight test indicated that the temperature of 2 wt% RSF/MoS2 nanoparticles hybrid fibers could rise from 20.0 °C to 81.0 °C in 1 min and 98.6 °C in 10 min, exhibiting good thermal stability. It was also demonstrated that fabrics made by manual blending portrayed excellent photothermal properties. The addition of MoS2 nanoparticles could improve the toughness of hybrid fibers, which may be since the mixing of MoS2 nanoparticles hindered the self-assembly of β-sheets in RSF solution in a concentration-dependent manner because RSF/MoS2 nanoparticles hybrid fibers showed a lower β-sheet content, crystallinity, and smaller crystallite size. This study describes a new way of producing high toughness and photothermal properties fibers for multifunctional fibers' applications.

Smartphone-Based Dual-Channel Immunochromatographic Test Strip with Polymer Quantum Dot Labels for Simultaneous Detection of Cypermethrin and 3-Phenoxybenzoic Acid

Currently, gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-MS (LC-MS) are the primary methods used to detect pesticides and their metabolites for biomonitoring of exposure. Although GC-MS and LC-MS can provide accurate and sensitive measurements, these techniques are not suitable for point-of-care or in-field biomonitoring applications. The objective of this work is to develop a smartphone-based dual-channel immunochromatographic test strip (ICTS) for on-site biomonitoring of exposure to cypermethrin by simultaneous detection of cypermethrin and its metabolite, 3-phenoxybenzoic acid (3-PBA). Polymer carbon dots (PCDs) with ultrahigh fluorescent brightness were synthesized and used as a signal amplifier in ICTS assay. Cypermethrin (a representative pyrethroid pesticide) and its major metabolite 3-PBA were simultaneously detected to provide more comprehensive analysis of cypermethrin exposure. After competitive immunoreactions between the target sample and the coating antigens preloaded on the test line, the tracer antibody (PCD-conjugated antibody) was quantitatively captured on the test lines. The captured PCDs were inversely proportional to the amount of the target compound in the sample. The red fluorescence on the test line was then recorded using a smartphone-based device capable of conducting image analysis and recording. Under optimal conditions, the sensor showed excellent linear responses for detecting cypermethrin and 3-PBA ranging from 1 to 100 ng/mL and from 0.1 to 100 ng/mL, respectively, and the limits of detection were calculated to be ∼0.35 ng/mL for cypermethrin and ∼0.04 ng/mL for 3-PBA. The results demonstrate that the ICTS device is promising for accurate point-of-care biomonitoring of pesticide exposure.

Examining the Transient Dark State in Protein-Quantum Dot Interaction by Relaxation-Based Solution NMR

We probed the "dark" state involved in the protein-quantum dot (QD) interaction using a relaxation-based solution nuclear magnetic resonance (NMR) approach. We examined the dynamics and exchange kinetics of the ubiquitin-CdTe model system, which undergoes a fast exchange in the transverse relaxation time scale. We applied the recently developed dark-state exchange saturation transfer (DEST), lifetime line broadening (ΔR₂), and exchange-induced chemical shift (δ_ex) solution NMR techniques to obtain a residue-specific binding behavior of the protein on the QD surface. The variation in the estimated ¹⁵N-R₂^bound values clearly shows the dynamic nature of bound Ub. Upon mapping the amino acid residues showing a faster relaxation rate on the electrostatic potential surface of the protein, we have determined that the interaction is preferably electrostatic, and the amino acid residues involved in binding lie on the positively charged surface of the protein. We believe that our experimental approach should provide more in-depth knowledge to engineer new hybrid protein-QD systems in the future.

The curvature of gold nanoparticles influences the exposure of amyloid-β and modulates its aggregation process

Gold nanoparticles (GNP) are tunable nanomaterials that can be used to develop rational therapeutic inhibitors against the formation of pathological aggregates of proteins. In the case of the pathological aggregation of the amyloid-β protein (Aβ), the shape of the GNP can slow down or accelerate its aggregation kinetics. However, there is a lack of elementary knowledge about how the curvature of GNP alters the interaction with the Aβ peptide and how this interaction modifies key molecular steps of fibril formation. In this study, we analysed the effect of flat gold nanoprisms (GNPr) and curved gold nanospheres (GNS) on in vitro Aβ42 fibril formation kinetics by using the thioflavin-based kinetic assay and global fitting analysis, with several models of aggregation. Whereas GNPr accelerate the aggregation process and maintain the molecular mechanism of aggregation, GNS slow down this process and modify the molecular mechanism to one of fragmentation/secondary nucleation, with respect to controls. These results can be explained by a differential interaction between the Aβ peptide and GNP observed by Raman spectroscopy. While flat GNPr expose key hydrophobic residues involved in the Aβ peptide aggregation, curved GNS hide these residues from the solvent. Thus, this study provides mechanistic insights to improve the rational design of GNP nanomaterials for biomedical applications in the field of amyloid-related aggregation.

Protein-biomolecule interactions play a major role in shaping corona proteome: studies on milk interacted dietary particles

Despite the significance of surface absorbed proteins in determining the biological identity of nanoparticles (NPs) entering the human body, little is known about the surface corona and factors that shape their formation on dietary particles used as food additives. In this study, food grade NPs of silica and titania and their food additive counterparts (E551 and E171) were interacted with milk proteins or with skimmed milk and the levels of protein adsorption were quantified. Characteristics of proteins correlating with their level of adsorption to NPs were determined using partial least squares regression analysis. Results from individual protein-particle interactions revealed the significance of factors such as zeta potential, hydrophobicity and hydrodynamic size of particles, and protein characteristics such as the number of beta strands, isoelectric points, the number of amino acid units (Ile, Tyr, Ala, Gly, Pro, Asp, and Arg), and phosphorylation sites on their adsorption to particles. Similar regression analysis was performed to identify the characteristics of twenty abundant and enriched proteins (identified using LC-MS/MS analysis) for their association with the surface corona of milk-interacted particles. Contrary to individual protein-particle interactions, protein characteristics such as helices, turns, protein structures, disulfide bonds, the number of amino acid units (Cys, Met, Leu, and Trp), and Fe binding sites were significant for their association with the surface corona of milk interacted particles. This difference in factors identified from individual proteins and milk interacted particles suggested possible interactions of proteins with surface adsorbed biomolecules as revealed by scanning transmission X-ray microscopy and other biochemical assays.