Logic-embedded vectors for intracellular partitioning, endosomal escape, and exocytosis of nanoparticles

A new generation of nanocarriers, logic-embedded vectors (LEVs), is endowed with the ability to localize components at multiple intracellular sites, thus creating an opportunity for synergistic control of redundant or dual-hit pathways. LEV encoding elements include size, shape, charge, and surface chemistry. In this study, LEVs consist of porous silicon nanocarriers, programmed for cellular uptake and trafficking along the endosomal pathway, and surface-tailored iron oxide nanoparticles, programmed for endosomal sorting and partitioning of particles into unique cellular locations. In the presence of persistent endosomal localization of silicon nanocarriers, amine-functionalized nanoparticles are sorted into multiple vesicular bodies that form novel membrane-bound compartments compatible with cellular secretion, while chitosan-coated nanoparticles escape from endosomes and enter the cytosol. Encapsulation within the porous silicon matrix protects these nanoparticle surface-tailored properties, and enhances endosomal escape of chitosan-coated nanoparticles. Thus, LEVs provide a mechanism for shielded transport of nanoparticles to the lesion, cellular manipulation at multiple levels, and a means for targeting both within and between cells.     

Quantitative Evaluation of the Cellular Uptake of Nanodiamonds by Monocytes and Macrophages

Fluorescent nanodiamonds (FNDs) with negative nitrogen-vacancy (NV⁻) defect centers are great probes for biosensing applications, with potential to act as biomarkers for cell differentiation. To explore this concept, uptake of FNDs (≈120 nm) by THP-1 monocytes and monocyte-derived M0-macrophages is studied. The time course analysis of FND uptake by monocytes confirms differing FND-cell interactions and a positive time-dependence. No effect on cell viability, proliferation, and differentiation potential into macrophages is observed, while cells saturated with FNDs, unload the FNDs completely by 25 cell divisions and subsequently take up a second dose effectively. FND uptake variations by THP-1 cells at early exposure-times indicate differing phagocytic capability. The cell fraction that exhibits relatively enhanced FND uptake is associated to a macrophage phenotype which derives from spontaneous monocyte differentiation. In accordance, chemical-differentiation of the THP-1 cells into M0-macrophages triggers increased and homogeneous FND uptake, depleting the fraction of cells that were non-responsive to FNDs. These observations imply that FND uptake allows for distinction between the two cell subtypes based on phagocytic capacity. Overall, FNDs demonstrate effective cell labeling of monocytes and macrophages, and are promising candidates for sensing biological processes that involve cell differentiation.     

Elucidating the Influences of Size,Surface Chemistry,and Dynamic Flow on Cellular Association of Nanoparticles Made by Polymerization‐Induced Self‐Assembly

The size and surface chemistry of nanoparticles dictate their interactions with biological systems. However, it remains unclear how these key physicochemical properties affect the cellular association of nanoparticles under dynamic flow conditions encountered in human vascular networks. Here, the facile synthesis of novel fluorescent nanoparticles with tunable sizes and surface chemistries and their association with primary human umbilical vein endothelial cells (HUVECs) is reported. First, a one‐pot polymerization‐induced self‐assembly (PISA) methodology is developed to covalently incorporate a commercially available fluorescent dye into the nanoparticle core and tune nanoparticle size and surface chemistry. To characterize cellular association under flow, HUVECs are cultured onto the surface of a synthetic microvascular network embedded in a microfluidic device (SynVivo, INC). Interestingly, increasing the size of carboxylic acid–functionalized nanoparticles leads to higher cellular association under static conditions but lower cellular association under flow conditions, whereas increasing the size of tertiary amine–decorated nanoparticles results in a higher level of cellular association, under both static and flow conditions. These findings provide new insights into the interactions between polymeric nanomaterials and endothelial cells. Altogether, this work establishes innovative methods for the facile synthesis and biological characterization of polymeric nanomaterials for various potential applications.     

Encapsulation of Plasmid DNA by Nanoscale Metal–Organic Frameworks for Efficient Gene Transportation and Expression

The intracellular delivery and functionalization of genetic molecules play critical roles in gene‐based theranostics. In particular, the delivery of plasmid DNA (pDNA) with safe nonviral vectors for efficient intracellular gene expression has received increasing attention; however, it still has some limitations. A facile one‐pot method is employed to encapsulate pDNA into zeolitic imidazole framework‐8 (ZIF‐8) and ZIF‐8‐polymer vectors via biomimetic mineralization and coprecipitation. The pDNA molecules are found to be well distributed inside both nanostructures and benefit from their protection against enzymatic degradation. Moreover, through the use of a polyethyleneimine (PEI) 25 kD capping agent, the nanostructures exhibit enhanced loading capacity, better pH responsive release, and stronger binding affinity to pDNA. From in vitro experiments, the cellular uptake and endosomal escape of the protected pDNA are greatly improved with the superior ZIF‐8‐PEI 25 kD vector, leading to successful gene expression with high transfection efficacy, comparable to expensive commercial agents. New cost‐effective avenues to develop metal–organic‐framework‐based nonviral vectors for efficient gene delivery and expression are provided.     

Drug delivery: Logic‐Embedded Vectors for Intracellular Partitioning,Endosomal Escape,and Exocytosis of Nanoparticles (Small 23/2010)

A new generation of nanocarriers, logic‐embedded vectors (LEVs), is endowed with the ability to localize components at multiple intracellular sites, thus creating an opportunity for synergistic control of redundant or dual‐hit pathways. LEV encoding elements include size, shape, charge, and surface chemistry. In this study, LEVs consist of porous silicon nanocarriers, programmed for cellular uptake and trafficking along the endosomal pathway, and surface‐tailored iron oxide nanoparticles, programmed for endosomal sorting and partitioning of particles into unique cellular locations. In the presence of persistent endosomal localization of silicon nanocarriers, amine‐functionalized nanoparticles are sorted into multiple vesicular bodies that form novel membrane‐bound compartments compatible with cellular secretion, while chitosan‐coated nanoparticles escape from endosomes and enter the cytosol. Encapsulation within the porous silicon matrix protects these nanoparticle surface‐tailored properties, and enhances endosomal escape of chitosan‐coated nanoparticles. Thus, LEVs provide a mechanism for shielded transport of nanoparticles to the lesion, cellular manipulation at multiple levels, and a means for targeting both within and between cells.     

Reversibly Extracellular pH Controlled Cellular Uptake and Photothermal Therapy by PEGylated Mixed‐Charge Gold Nanostars

Shielding nanoparticles from nonspecific interactions with normal cells/tissues before they reach and after they leave tumors is crucial for the selective delivery of NPs into tumor cells. By utilizing the reversible protonation of weak electrolytic groups to pH changes, long‐chain amine/carboxyl‐terminated polyethylene glycol (PEG) decorated gold nanostars (GNSs) are designed, exhibiting reversible, significant, and sensitive response in cell affinity and therapeutic efficacy to the extracellular pH (pHe) gradient between normal tissues and tumors. This smart nanosystem shows good dispersity and unimpaired photothermal efficacy in complex bioenvironment at pH 6.4 and 7.4 even when their surface charge is neutral. One PEGylated mixed‐charge GNSs with certain surface composition, GNS‐N/C 4 , exhibits high cell affinity and therapeutic efficacy at pH 6.4, and low affinity and almost “zero” damage to cells at pH 7.4. Remarkably, this significant and sensitive response in cell affinity and therapeutic efficacy is reversible as local pH alternated. In vivo, GNS‐N/C 4 shows higher accumulation in tumors and improved photothermal therapeutic efficacy than pH‐insensitive GNSs. This newly developed smart nanosystem, whose cell affinity reversibly transforms in response to pHe gradient with unimpaired biostability, provides a novel effective means of tumor‐selective therapy.     

Synthesis of Silica Vesicles with Controlled Entrance Size for High Loading,Sustained Release,and Cellular Delivery of Therapeutical Proteins

A rationally designed two‐step synthesis of silica vesicles is developed with the formation of vesicular structure in the first step and fine control over the entrance size by tuning the temperature in the second step. The silica vesicles have a uniform size of ≈50 nm with excellent cellular uptake performance. When the entrance size is equal to the wall thickness, silica vesicles after hydrophobic modification show the highest loading amount (563 mg/g) towards Ribonuclease A with a sustained release behavior. Consequently, the silica vesicles are excellent nano‐carriers for cellular delivery applications of therapeutical biomolecules.     

Modelling the Effect of Initial Grain Size on Dynamic Recrystallization Using a Modified Cellular Automata and a Adaptive Response Surface Method

A modified cellular automata (CA) model of dynamic recrystallization (DRX) and a flow stress-based nucleation parameter identification method have been developed.In the method,the modified CA model,which takes the role of deformation degree on nucleation behavior into consideration,is coupled with an adaptive response surface model (ARSM) to search for the optimum nucleation parameter.The DRX behavior of an oxygen free high conductivity (OFHC) copper with different initial grain sizes has been taken as an e...     

Particle Size,Surface Coating,and PEGylation Influence the Biodistribution of Quantum Dots in Living Mice

This study evaluates the influence of particle size, PEGylation, and surface coating on the quantitative biodistribution of near‐infrared‐emitting quantum dots (QDs) in mice. Polymer‐ or peptide‐coated ⁶⁴Cu‐labeled QDs 2 or 12 nm in diameter, with or without polyethylene glycol (PEG) of molecular weight 2000, are studied by serial micropositron emission tomography imaging and region‐of‐interest analysis, as well as transmission electron microscopy and inductively coupled plasma mass spectrometry. PEGylation and peptide coating slow QD uptake into the organs of the reticuloendothelial system (RES), liver and spleen, by a factor of 6–9 and 2–3, respectively. Small particles are in part renally excreted. Peptide‐coated particles are cleared from liver faster than physical decay alone would suggest. Renal excretion of small QDs and slowing of RES clearance by PEGylation or peptide surface coating are encouraging steps toward the use of modified QDs for imaging living subjects.     

Persistent Photoconductivity,Nanoscale Topography,and Chemical Functionalization Can Collectively Influence the Behavior of PC12 Cells on Wide Bandgap Semiconductor Surfaces

Wide bandgap semiconductors such as gallium nitride (GaN) exhibit persistent photoconductivity properties. The incorporation of this asset into the fabrication of a unique biointerface is presented. Templates with lithographically defined regions with controlled roughness are generated during the semiconductor growth process. Template surface functional groups are varied using a benchtop surface functionalization procedure. The conductivity of the template is altered by exposure to UV light and the behavior of PC12 cells is mapped under different substrate conductivity. The pattern size and roughness are combined with surface chemistry to change the adhesion of PC12 cells when the GaN is made more conductive after UV light exposure. Furthermore, during neurite outgrowth, surface chemistry and initial conductivity difference are used to facilitate the extension to smoother areas on the GaN surface. These results can be utilized for unique bioelectronics interfaces to probe and control cellular behavior.     

Factors Ruling the Uptake of Silica Nanoparticles by Mesenchymal Stem Cells: Agglomeration Versus Dispersions,Absence Versus Presence of Serum Proteins

The results of a systematic investigation of the role of serum proteins on the interaction of silica nanoparticles (NP) doped in their bulk with fluorescent molecules (IRIS Dots, 50 nm in size), with human mesenchymal stem cells (hMSCs) are reported. The suspension of IRIS Dots in bare Dulbecco‐modified Eagle's medium results in the formation of large agglomerates (≈1.5 μm, by dynamic light scattering), which become progressively smaller, down to ≈300 nm in size, by progressively increasing the fetal bovine serum (FBS) content of the solutions along the series 1.0%, 2.5%, 6.0%, and 10.0% v/v. Such difference in NP dispersion is maintained in the external cellular microenvironment, as observed by confocal microscopy and transmission electron microscopy. As a consequence of the limited diffusion of proteins in the inter‐NP spaces, the surface of NP agglomerates is coated by a protein corona independently of the agglomerate size/FBS concentration conditions (ζ‐potential and UV circular dichroism measurements). The protein corona appears not to be particularly relevant for the uptake of IRIS Dots by hMSCs, whereas the main role in determining the internalization rate is played by the absence/presence of serum proteins in the extracellular media.     

Folding 2D Structures into 3D Configurations at the Micro/Nanoscale: Principles,Techniques, and Applications

Compared to their 2D counterparts, 3D micro/nanostructures show larger degrees of freedom and richer functionalities; thus, they have attracted increasing attention in the past decades. Moreover, extensive applications of 3D micro/nanostructures are demonstrated in the fields of mechanics, biomedicine, optics, etc., with great advantages. However, the mainstream micro/nanofabrication technologies are planar ones; therefore, they cannot be used directly for the construction of 3D micro/nanostructures, making 3D fabrication at the micro/nanoscale a great challenge. A promising strategy to overcome this is to combine the state‐of‐the‐art planar fabrication techniques with the folding method to produce 3D structures. In this strategy, 2D components can be easily produced by traditional planar techniques, and then, 3D structures are constructed by folding each 2D component to specific orientations. In this way, not only will the advantages of existing planar techniques, such as high precision, programmable patterning, and mass production, be preserved, but the fabrication capability will also be greatly expanded without complex and expensive equipment modification/development. The goal here is to highlight the recent progress of the folding method from the perspective of principles, techniques, and applications, as well as to discuss the existing challenges and future prospectives.     

Quantitative Determination of Contribution by Enhanced Local Electric Field,Antenna‐Amplified Light Scattering,and Surface Energy Transfer to the Performance of Plasmonic Organic Solar Cells

Plasmonic metal nanostructures are widely used as subwavelength light concentrators to enhance light harvesting of organic solar cells through two photophysical effects, including enhanced local electric field (ELEF) and antenna‐amplified light scattering (AALS), while their adverse quenching effect from surface energy transfer (SET) should be suppressed. In this work, a comprehensive study to unambiguously distinguish and quantitatively determine the specific influence and contribution of each effect on the overall performance of organic solar cells incorporated with Ag@SiO₂ core–shell nanoparticles (NPs) is presented. By investigating the photon conversion efficiency (PCE) as a function of the SiO₂ shell thickness, a strong competition between the ELEF and SET effects in the performance of the devices with the NPs embedded in the active layers is found, leading to a maximum PCE enhancement of 12.4% at the shell thickness of 5 nm. The results give new insights into the fundamental understanding of the photophysical mechanisms responsible for the performance enhancement of plasmonic organic solar cells and provide important guidelines for designing more‐efficient plasmonic solar cells in general.