Biomedical Nanoparticles Research Articles

Green synthesis of silver, starch, and zinc oxide mediated nanoparticles with probiotics and plant extracts, their characterization and anti-bacterial activity

Nanotechnology has various applications in all branches of science, including engineering, medicine, pharmacy, and other related fields. Conventional techniques, such as the chemical reduction approach, which produces nanoparticles (NPs) using various hazardous chemicals, offer several health risks due to their toxicity and raise serious environmental concerns. In contrast, other techniques are expensive and need a lot of energy. More than 70 % of pathogenic bacterial strains have developed resistance to at least one class of antibiotics, leading to an increase in life-threatening bacterial infections that pose a significant health risk. However, the creation of NPs by biogenic synthesis is risk-free for the environment and clean enough for biological use. This study was aimed at synthesis of novel Moringa oleifera mediated starch capped silver-zinc NPs and green synthesis of ZnO nanoparticles from Aloe vera, papaya, and Lactobacillus plantarum. Antimicrobial activity of both NPs was tested against Gram-negative antibiotic-resistant bacteria Pseudomonas aeruginosa, Gram-positive bacteria Staphylococcus aureus (ATCC 6538), and two foodborne pathogens Listeria monocytogenes and Campylobacter jejuni. Ultraviolet–visible spectroscopy, Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy were used for characterization. Majority of the research studies stress the flexibility, repeatability, and desirable features of the metals, polymers, and plant components employed in the production of biomedical nanoparticles. Such an intuitive approach provides several advantages, particularly a reasonable total expense, compliance with healthcare and pharmaceutical implementations, and the ability to produce massive volumes for industrial use. The novelty of the presented work lies in the unusual combination of silver, starch, and zinc oxide nanoparticles using Moringa oleifera, which is an eco-friendly alternative to chemical-based methods. This research exhibits the formation of well-defined nanoparticles with strong antibacterial activity against a wide range of pathogens, giving us insights into their potential applications in various biomedical fields.

Protein corona dynamicity contributes to biological destiny disparities of nanoparticles

Extracellular protein coronas (exPCs), which have been identified in various biofluids, are recognized for their pivotal role in mediating the interaction between nanoparticles and the cytomembrane. However, it is still unclear whether various exPCs can induce different levels of intracellular proteostasis, which is of utmost importance in preserving cellular function, and eliciting distinct intracellular biological behaviors. To investigate this, two types of exPC-coated iron oxide nanoparticles (IONPs) are prepared and used to investigate the influence of exPCs on extracellular and intracellular biological outcomes. The results demonstrate that the formation of exPCs promotes the colloidal stability of IONPs, and the discrepancies in the components of the two exPCs, including opsonin, dysopsonin, and lipoprotein, are responsible for the disparities in cellular uptake and endocytic pathways. Moreover, the differential evolution of the two exPCs during cellular internalization leads to distinct autophagy and glycolysis activities, which can be attributed to the altered depletion of angiopoietin 1 during the formation of intracellular protein coronas, which ultimately impacts the PI3K/AKT-mTOR signaling. These findings offer valuable insights into the dynamic characteristics of exPCs during cellular internalization, and their consequential implications for cellular internalization and intracellular metabolism activity, which may facilitate the comprehension of PCs on biological effects of NPs and expedite the design and application of biomedical nanoparticles.

Multi-Criteria Decision-Making Approach for Pre-Synthesis Selection of the Optimal Physicochemical Properties of TiO2 Photocatalytic Nanoparticles for Biomedical and Environmental Applications.

Nanomaterials are widely used in several biomedical and environmental applications, due to their ideal properties. However, the synthetic and characterization procedure requires significant costs and has a negative environmental impact. Various methods are available in order to control the pre-synthesis design of the produced materials, predicting their behavior and minimizing the series of experiments. Multi-Criteria Decision-Making is proposed in this study in order to determine the best combination of the physicochemical parameters and to define the best alternative among fifteen different samples of nanostructured titanium dioxide. In particular, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method was applied to achieve a final ranking of the available alternatives by avoiding several of the trials that would follow testing the biological effect and the photocatalytic degradation of organic pollutants. Thus, this approach helps us to stay environmentally and ethically correct, saving time, money, and energy and also providing an optimization of the nanomaterials that are developed.

Dual-reactive single-chain polymer nanoparticles for orthogonal functionalization through active ester and click chemistry

Glucose has been extensively studied as a targeting ligand on nanoparticles for biomedical nanoparticles. A promising nanocarrier platform are single-chain polymer nanoparticles (SCNPs). SCNPs are well-defined 5–20 nm semi-flexible nano-objects, formed by intramolecularly crosslinked linear polymers. Functionality can be incorporated by introducing labile pentafluorophenyl (PFP) esters in the polymer backbone, which can be readily substituted by functional amine-ligands. However, not all ligands are compatible with PFP-chemistry, requiring different ligation strategies for increasing versatility of surface functionalization. Here, we combine active PFP-ester chemistry with copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) click chemistry to yield dual-reactive SCNPs. First, the SCNPs are functionalized with increasing amounts of 1-amino-3-butyne groups through PFP-chemistry, leading to a range of butyne-SCNPs with increasing terminal alkyne-density. Subsequently, 3-azido-propylglucose is conjugated through the glucose C1- or C6-position by CuAAC click chemistry, yielding two sets of glyco-SCNPs. Cellular uptake is evaluated in HeLa cancer cells, revealing increased uptake upon higher glucose-surface density, with no apparent positional dependance. The general conjugation strategy proposed here can be readily extended to incorporate a wide variety of functional molecules to create vast libraries of multifunctional SCNPs.

The Influence of Size on the Intracranial Distribution of Biomedical Nanoparticles Administered by Convection-enhanced Delivery in Minipigs.

Because of the blood-brain barrier (BBB), successful drug delivery to the brain has long been a key objective for the medical community, calling for pioneering technologies to overcome this challenge. Convection-enhanced delivery (CED), a form of direct intraparenchymal microinfusion, shows promise but requires optimal infusate design and real-time distribution monitoring. The size of the infused substances appears to be especially critical, with current knowledge being limited. Herein, we examined the intracranial administration of polyethylene glycol (PEG)-coated nanoparticles (NPs) of various sizes using CED in groups of healthy minipigs (n = 3). We employed stealth liposomes (LIPs, 130 nm) and two gold nanoparticle designs (AuNPs) of different diameters (8 and 40 nm). All were labeled with copper-64 for quantitative and real-time monitoring of the infusion via positron emission tomography (PET). NPs were infused via two catheters inserted bilaterally in the putaminal regions of the animals. Our results suggest CED with NPs holds promise for precise brain drug delivery, with larger LIPs exhibiting superior distribution volumes and intracranial retention over smaller AuNPs. PET imaging alongside CED enabled dynamic visualization of the process, target coverage, timely detection of suboptimal infusion, and quantification of distribution volumes and concentration gradients. These findings may augment the therapeutic efficacy of the delivery procedure while mitigating unwarranted side effects associated with nonvisually monitored delivery approaches. This is of vital importance, especially for chronic intermittent infusions through implanted catheters, as this information enables informed decisions for modulating targeted infusion volumes on a catheter-by-catheter, patient-by-patient basis.

Green Nanotechnology: How Plants Can Help Synthesize Nanoparticles for Biomedical and Environmental Purposes

Green Nanotechnology: How Plants Can Help Synthesize Nanoparticles for Biomedical and Environmental Purposes

Micro-Supercapacitors Based on Fungi-Derived Biocarbon Microfibers Infused with NiMoO Nanoparticles for Biomedical and E-Skin Applications

Micro-Supercapacitors Based on Fungi-Derived Biocarbon Microfibers Infused with NiMoO Nanoparticles for Biomedical and E-Skin Applications

Application and Method of Surface Plasmon Resonance Technology in the Preparation and Characterization of Biomedical Nanoparticle Materials.

Surface Plasmon Resonance (SPR) technology, as a powerful analytical tool, plays a crucial role in the preparation, performance evaluation, and biomedical applications of nanoparticles due to its real-time, label-free, and highly sensitive detection capabilities. In the nanoparticle preparation process, SPR technology can monitor synthesis reactions and surface modifications in real-time, optimizing preparation techniques and conditions. SPR enables precise measurement of interactions between nanoparticles and biomolecules, including binding affinities and kinetic parameters, thereby assessing nanoparticle performance. In biomedical applications, SPR technology is extensively used in the study of drug delivery systems, biomarker detection for disease diagnosis, and nanoparticle-biomolecule interactions. This paper reviews the latest advancements in SPR technology for nanoparticle preparation, performance evaluation, and biomedical applications, discussing its advantages and challenges in biomedical applications, and forecasting future development directions.

Biosynthesis of Selected Nanoparticles for Biomedical Applications

Nanoparticles (NPs) are materials with a size scale of 100 nm or less. They are produced using a combination of chemical and physical techniques, and frequently include the use of hazardous substances. These hazardous substances are difficult to remove from nanoparticle surfaces, making them bioincompatible and limiting their application as biomedical nanoparticles. Nanoparticles can currently be synthesized biologically using methods based on green chemistry. The fusion of nanotechnology and biology has given rise to a new field called nanobiotechnology, which aims to harness biological entities such as actinomycetes, algae, bacteria, fungi, viruses, yeast, and plants in a number of physicochemical, biochemical, and biophysical processes. Plant extracts have been used in biological applications because they are a rich source of phytomolecules and because their capping and reducing capabilities have been used in the production of metal and metal oxide NPs. The biosynthesized NPs have not only been examined for their antibacterial, antifungal, antioxidant, anticancer, and biocompatibility properties but also for their morphology using a number of analytical techniques. This approach, which is affordable and environmentally friendly, could substitute traditional chemical and physical methods for biomedical applications.

Emerging Trends in Zinc Ferrite Nanoparticles for Biomedical and Environmental Applications.

Over the last fewdecades, the application of nanoparticles (NPs) gained immenseattention towardsenvironmental and biomedical applications. NPs are ultra-small particles having size ranges from 1 to 100nm. NPs loaded with therapeutic or imaging compounds have proved a versatile approach towards healthcare improvements. Among various inorganic NPs, zinc ferrite (ZnFe2O4) NPs are considered asnon-toxic and having animproved drug delivery characteristics. Several studies have reported broader applications of ZnFe2O4 NPs for treating carcinoma and various infectious diseases. Additionally, these NPs are beneficial for reducing organic and inorganic environmental pollutants. This review discussesaboutvarious methods to fabricate ZnFe2O4 NPs and their physicochemical properties. Further, their biomedical and environmental applications have also been exploredcomprehensively.

Magnetic heating of water dispersible and size-controlled superparamagnetic cobalt iron oxide nanoparticles

Magnetic nanoparticles have been of great interest for various biomedical applications due to their controllability in the distance. Monodisperse superparamagnetic CoFe2O4 (CFO) nanoparticles were synthesized by solvothermal method with oleic acid. The oleic acid ligands are exchanged with citric acid to obtain water-dispersible citric acid-coated CA (CFO–CA) nanoparticles. The M–H curve recorded at room temperature shows the superparamagnetic nature of CFO nanoparticles for both oleic- and citric-coated samples. The magnetic heating performance of CFO–CA shows an exciting dependence on the particle size and surface functionality. The hyperthermia efficiency of CFO–CA nanoparticles increases with increasing magnetic field strength and nanoparticle concentration. A specific absorption ratio value of 152.7 W/g obtained in this study is comparable to other investigations, demonstrating a great potential of CFO–CA nanoparticles for hyperthermia-based treatments. This controlled synthesis process can be applied to various functional biomedical nanoparticles to prepare nanoparticles with designed surface moieties for further potential applications.

Photocatalytic Synthesis of a Polydopamine-Coated Acellular Mega-Hemoglobin as a Potential Oxygen Therapeutic with Antioxidant Properties.

Hemoglobin-based oxygen carriers (HBOCs) are being developed to overcome limitations associated with transfusion of donated red blood cells (RBCs) such as potential transmission of blood-borne pathogens and limited ex vivo storage shelf-life. Annelid erythrocruorin (Ec) derived from the worm Lumbricus terrestris (Lt) is an acellular mega-hemoglobin that has shown promise as a potential HBOC due to the large size of its oligomeric structure, thus overcoming limitations of unmodified circulating cell-free hemoglobin (Hb). With a large molecular weight of 3.6 MDa compared to 64.5 kDa for human Hb (hHb) and 144 oxygen-binding globin subunits compared to the 4 globin subunits of hHb, LtEc does not extravasate from the circulation to the same extent as hHb. LtEc is stable in the circulation without RBC membrane encapsulation and has a lower rate of auto-oxidation compared to acellular hHb, which allows the protein to remain functional for longer periods of time in the circulation compared to HBOCs derived from mammalian Hbs. Surface coatings, such as poly(ethylene glycol) (PEG) and oxidized dextran (Odex), have been investigated to potentially reduce the immune response and improve the circulation time of LtEc in vivo. Polydopamine (PDA) is a hydrophilic, biocompatible, bioinspired polymer coating used for biomedical nanoparticle assemblies and coatings and has previously been investigated for the surface coating of hHb. PDA is typically synthesized via the self-polymerization of dopamine (DA) under alkaline (pH > 8.0) conditions. However, at pH > 8.0, the oligomeric structure of LtEc begins to dissociate. Therefore, in this study, we investigated a photocatalytic method of PDA polymerization on the surface of LtEc using 9-mesityl-10-methylacridinium tetrafluoroborate (Acr-Mes) to drive PDA polymerization under physiological conditions (pH 7.4, 25 °C) over 2, 5, and 16 h in order to preserve the size and structure of LtEc. The resulting structural, biophysical, and antioxidant properties of PDA surface-coated LtEc (PDA-LtEc) was characterized using various techniques. PDA-LtEc showed an increase in measured particle size, molecular weight, and surface ζ-potential with increasing reaction time from t = 2 to 16 h compared to unmodified LtEc. PDA-LtEc reacted for 16 h was found to have reduced oxygen-binding cooperativity and slower deoxygenation kinetics compared to PDA-LtEc with lower levels of polymerization (t = 2 h), but there was no statistically significant difference in oxygen affinity. The thickness of the PDA coating can be controlled and in turn the biophysical properties can be tuned by changing various reaction conditions. PDA-LtEc was shown to demonstrate an increased level of antioxidant capacity (ferric iron reduction and free-radical scavenging) when synthesized at a reaction time of t = 16 h compared to LtEc. These antioxidant properties may prove beneficial for oxidative protection of PDA-LtEc during its time in the circulation. Hence, we believe that PDA-LtEc is a promising oxygen therapeutic for potential use in transfusion medicine applications.

Recent developments in microfluidic technology for synthesis and toxicity-efficiency studies of biomedical nanomaterials

Microfluidic technology is a relatively new field among the various conventional bulk techniques employed for nanomaterial synthesis. Nanoparticles (NPs) produced using such methods generally have poor surface features, morphology, uncontrolled size and broad size distributions. NPs especially used in the biomedical sector require a degree of control over their size, morphology, and polydispersity to improve their functionality. To synthesize such NPs, microfluidic devices are ideal as parameters such as mixing rates, flow rates, mixing volumes, multiphase reactions can be controlled on the micro/nanoscale. There are several strategies and challenges in the synthesis of nanoparticles from organic and inorganic materials in a microfluidic platform. The challenges faced during the design and implementation of these devices, such as the large scale production and interaction with soft lithography materials, which are overcome by the use of the bulk technique in conjugation with microfluidics, use of parallelisation of the processes with the search for new fabrication materials. On the other hand, organ-on-chip (OOC) are analytical microfluidic devices in which cell cutures are present and can mimic an organ along with its physio-chemical properties to study cell-nanoparticle interaction. There are several issues with the construction of such devices as cell cultures within the device can be affected by the fabrication materials. As such new biocompatible materials are being printed into more appropriate designs, utilized to contain said cultures and reduce the risk of error in the analysis of NP properties, such as efficiency and toxicity. This review aims to discuss the recent developments in the field of synthesis as well as toxicity and efficacy evaluations of biomedical nanoparticles using microfluidic technology.

An Up‐to‐Date Review on Alginate Nanoparticles and Nanofibers for Biomedical and Pharmaceutical Applications

AbstractAlginate is a naturally occurring polysaccharide commonly derived from brown algae cell walls which possesses unique features that make it extremely promising for several biomedical and pharmaceutical purposes. Alginate biomaterials are indeed nowadays gaining increasing interest in drug delivery and tissue engineering applications owing to their intrinsic biocompatibility, non‐toxicity, versatility, low cost, and ease of functionalization. Specifically, alginate‐based nanostructures show enhanced capabilities with respect to alginate bulk materials in the targeted delivery of drugs and chemotherapies, as well as in helping tissue reparation and regeneration. Hence, it is not surprising that the number of scientific reports related to this topic have rapidly grown in the last decade. With these premises, the present review aims to provide a comprehensive state‐of‐the‐art of the most recent advances in the preparation of alginate‐based nanoparticles and electrospun nanofibers for drug delivery, cancer therapy, and tissue engineering purposes. After a short introduction concerning the general properties and uses of alginate and the concept of nanotechnology, the recent literature is then critically presented to highlight the main advantages of alginate‐based nanostructures. Finally, the current limitations and the future perspectives and objectives are discussed in detail.

In situ thermoresponsive curcumin-loaded dual polymeric nanoassemblies for wound healing and care of femoral fracture after surgery

Approximately 6.3 million fractures occur annually in the United States. Fractures (for example, hip fractures) occur in 2.4% population per year. A new clinical solution to this issue is the use of biomaterials with a dual purpose of bone healing and prevention of infection. In this study, advanced biomedical curcumin nanoparticles combined with a copolymeric matrix that had a dual function were developed and shown to promote antiinflammatory, functional recovery, and successful neuroprotective effects. The application of curcumin nanoparticles packaged in a thermoresponsive drug carrier device improves sustainability, bioavailability of blood, longevity, and biocompatibility. This nanocomposite showed enhancement of neuroprotection, axonal growth performance, and theoretically, functional recovery at the location of femoral fracture injury, by curcumin-primed polycaprolactone (PCL) (Cur-CS@PCL). Various microscopic methods (SEM, TEM, and LS) verified the morphology and shape of the manufactured Cur-CS@PCL nanoassemblies. In addition to these membranes being used at different temperatures, they improved the drug charge films and exhibited better-regulated release profiles for Cur. Thus, our data provide a simple hybrid clinical approach for the prevention and rehabilitation of femoral fractures in humans.

Advancing TEM Based Biomedical Nanoparticle Characterization: GMP validated TEM Workflow In a BSL2 Environment with CNN as Automated Analytical Tool

Advancing TEM Based Biomedical Nanoparticle Characterization: GMP validated TEM Workflow In a BSL2 Environment with CNN as Automated Analytical Tool

How Bacteria Change after Exposure to Silver Nanoformulations: Analysis of the Genome and Outer Membrane Proteome.

Objective: the main purpose of this work was to compare the genetic and phenotypic changes of E. coli treated with silver nanoformulations (E. coli BW25113 wt, E. coli BW25113 AgR, E. coli J53, E. coli ATCC 11229 wt, E. coli ATCC 11229 var. S2 and E. coli ATCC 11229 var. S7). Silver, as the metal with promising antibacterial properties, is currently widely used in medicine and the biomedical industry, in both ionic and nanoparticles forms. Silver nanoformulations are usually considered as one type of antibacterial agent, but their physical and chemical properties determine the way of interactions with the bacterial cell, the mode of action, and the bacterial cell response to silver. Methods: the changes in the bacterial genome, resulting from the treatment of bacteria with various silver nanoformulations, were verified by analyzing of genes (selected with mutfunc) and their conservative and non-conservative mutations selected with BLOSUM62. The phenotype was verified using an outer membrane proteome analysis (OMP isolation, 2-DE electrophoresis, and MS protein identification). Results: the variety of genetic and phenotypic changes in E. coli strains depends on the type of silver used for bacteria treatment. The most changes were identified in E. coli ATCC 11229 treated with silver nanoformulation signed as S2 (E. coli ATCC 11229 var. S2). We pinpointed 39 genes encoding proteins located in the outer membrane, 40 genes of their regulators, and 22 genes related to other outer membrane structures, such as flagellum, fimbria, lipopolysaccharide (LPS), or exopolysaccharide in this strain. Optical density of OmpC protein in E. coli electropherograms decreased after exposure to silver nanoformulation S7 (noticed in E. coli ATCC 11229 var. S7), and increased after treatment with the other silver nanoformulations (SNF) marked as S2 (noticed in E. coli ATCC 11229 var. S2). Increase of FliC protein optical density was identified in turn after Ag+ treatment (noticed in E.coli AgR). Conclusion: the results show that silver nanoformulations (SNF) exerts a selective pressure on bacteria causing both conservative and non-conservative mutations. The proteomic approach revealed that the levels of some proteins have changed after treatment with appropriate SNF.

Non-Ionic Surfactants for Stabilization of Polymeric Nanoparticles for Biomedical Uses.

Surfactants are essential in the manufacture of polymeric nanoparticles by emulsion formation methods and to preserve the stability of carriers in liquid media. The deposition of non-ionic surfactants at the interface allows a considerable reduction of the globule of the emulsion with high biocompatibility and the possibility of oscillating the final sizes in a wide nanometric range. Therefore, this review presents an analysis of the three principal non-ionic surfactants utilized in the manufacture of polymeric nanoparticles; polysorbates, poly(vinyl alcohol), and poloxamers. We included a section on general properties and uses and a comprehensive compilation of formulations with each principal non-ionic surfactant. Then, we highlight a section on the interaction of non-ionic surfactants with biological barriers to emphasize that the function of surfactants is not limited to stabilizing the dispersion of nanoparticles and has a broad impact on pharmacokinetics. Finally, the last section corresponds to a recommendation in the experimental approach for choosing a surfactant applying the systematic methodology of Quality by Design.

A new perspective of inorganic crystallization: Non-classical nucleation and growth

<p indent=0mm>Inorganic crystals surround us and play important roles in our daily life. They form integral parts of our body (e.g., bones), make up all the ground we stand on (ours and any other rocky planet consist of crystals), as well as show significant necessity for industrial processes and technologies (from table salt over concrete to biomedical nanoparticles). Accordingly, the formation mechanisms and properties of crystals have been extensively studied over the past decades. While there are longstanding theories on both the birth of crystals (nucleation) and their subsequent evolution (growth, recrystallization, and/or transformation), a vast amount of evidence suggests that the classical view on crystallization is over-simplified. In addition to the monomer-by-monomer (i.e., atoms, ions, or molecules) addition described in the classical theories, the particle attachment has been recognized as one of the most important pathways to inorganic crystallization. These particles range from the ion pairs to well-crystallized nanoparticles, such as amorphous precursors, magic-size clusters, nanocrystals, etc. The complexity of both the free-energy landscapes and reaction kinetics leads to diverse crystallization pathways. While experimental observations clearly demonstrate the non-classical crystallization pathways, many fundamental aspects remain unknown—Particularly the interaction of solution structure, interfacial forces, and particle motion. Thus, a predictive description linking molecular details to ensemble behavior is lacking. As such description develops, long-term interpretations of inorganic crystal formation should be revisited, which is important to broaden the scope of research across various disciplines such as geological events, biomineralization mechanisms, environmental remediation, and the development of environmentally functional materials. Based on several exemplary spotlights, the current state of the art in non-classical nucleation has been firstly illustrated in our review. Specifically, two non-classical nucleation pathways (i.e., the prenucleation clusters (PNCs) and aggregation pathway) in the current crystal research field are summarized. According to the PNCs pathway, PNCs were considered as the stable solute species with chainlike structural that are precursors to nucleation. Once system reaches the equilibrium ion activity product, the change in the chemistry of linkages within PNCs causes PNCs aggregation, as a consequence of nucleus formation. Another non-classical view (aggregation pathway) pointed that the fine crystalline nuclei first form in solution and then aggregate into a larger and more stable nucleus. Besides, the non-classical oriented attachment (OA) and random attachment (RA) growth pathways are also elucidated. OA and RA growth are similar in involving the self-assembly of primary nanocrystals. However, their main difference is the orientation of the crystal lattice at the grain boundary. For RA growth pathway, there is no particular preference for the attachment whereas for the OA growth, there is a common crystallographic alignment of the attachment to occur, which is allowing for continuous crystallographic planes. Finally, the implications and perspective of non-classical crystallization research are proposed. The aim of this review is to guide the readers through the complex world of crystallizing systems, highlighting a new perspective on non-classical crystallization of inorganic materials, which drives a true renaissance in the field and provides completely new perspectives on the underlying crystallization mechanisms. Additionally, through a mechanism-based understanding, we believed that non-classical crystallization processes can be used to produce innovative structures that retain the dimensional properties of their nanoscale building blocks and create materials with enhanced or novel physical and chemical properties.

Dynamic light scattering distributions by any means

Dynamic light scattering (DLS) is an essential technique for nanoparticle size analysis and has been employed extensively for decades, but despite its long history and popularity, the choice of weighting and mean of the size distribution often appears to be picked ad hoc to bring the results into agreement with other methods and expectations by any means necessary. Here, we critically discuss the application of DLS for nanoparticle characterization and provide much-needed clarification for ambiguities in the mean-value practice of commercial DLS software and documentary standards. We address the misleading way DLS size distributions are often presented, that is, as a logarithmically scaled histogram of measured relative quantities. Central values obtained incautiously from this representation often lead to significant interpretation errors. Through the measurement of monomodal nanoparticle samples having an extensive range of sizes (5 to 250 nm) and polydispersity, we similarly demonstrate that the default outputs of a frequently used DLS inversion method are ill chosen, as they are regularizer-dependent and significantly deviate from the cumulant z-average size. The resulting discrepancies are typically larger than 15% depending on the polydispersity index of the samples. We explicitly identify and validate the harmonic mean as the central value of the intensity-weighted DLS size distribution that expresses the inversion results consistently with the cumulant results. We also investigate the extent to which the DLS polydispersity descriptors are representative of the distributional quality and find them to be unreliable and misleading, both for monodisperse reference materials and broad-distribution biomedical nanoparticles. These results overall are intended to bring essential improvements and to stimulate reexamination of the metrological capabilities and role of DLS in nanoparticle characterization.