Chiral inorganic nanostructures strongly interact with photons changing their polarization state. The resulting circularly polarized light emission (CPLE) has cross‐disciplinary importance for a ...variety of chemical/biological processes and is essential for development of chiral photonics. However, the polarization effects are often complex and their interpretation is dependent on the several structural parameters of the chiral nanostructure. CPLE in nanostructured media has multiple origins and several optical effects are typically convoluted into a single output. Analyzing CPLE data obtained for nanoclusters, nanoparticles, nanoassemblies, and nanocomposites from metals, chalcogenides, perovskite, and other nanostructures, it is shown here that there are several distinct groups of nanomaterials for which CPLE is dominated either by circularly polarized luminescence (CPL) or circularly polarized scattering (CPS); there are also many nanomaterials for which they are comparable. The following points are also demonstrated: 1) CPL and CPS contributions involve light−matter interactions at different structural levels; 2) contribution from CPS is especially strong for nanostructured microparticles, nanoassemblies, and composites; and 3) engineering of materials with strongly polarized light emission requires synergistic implementation of CPL and CPS effects. These findings are expected to guide development of CPLE materials in a variety of technological fields, including 3D displays, information storage, biosensors, optical spintronics, and biological probes.
The circularly polarized light emission (CPLE) of chiral nanomaterials has cross‐disciplinary importance for fundamental sciences and technologies. Two size‐ and organization‐dependent contributions to CPLE are analyzed: circularly polarized luminescenceand circularly polarized scattering. Synergistic integration of luminescence and scattering outputs allows for high spectral purity and strong polarization rotation, which is demonstrated for inorganic nanomaterials with multiscale chirality.
Functional graphene nanomaterials (FGNs) are fast emerging materials with extremely unique physical and chemical properties and physiological ability to interfere and/or interact with bioorganisms; ...as a result, FGNs present manifold possibilities for diverse biological applications. Beyond their use in drug/gene delivery, phototherapy, and bioimaging, recent studies have revealed that FGNs can significantly promote interfacial biointeractions, in particular, with proteins, mammalian cells/stem cells, and microbials. FGNs can adsorb and concentrate nutrition factors including proteins from physiological media. This accelerates the formation of extracellular matrix, which eventually promotes cell colonization by providing a more beneficial microenvironment for cell adhesion and growth. Furthermore, FGNs can also interact with cocultured cells by physical or chemical stimulation, which significantly mediate their cellular signaling and biological performance. In this review, we elucidate FGNs–bioorganism interactions and summarize recent advancements on designing FGN-based two-dimensional and three-dimensional architectures as multifunctional biological platforms. We have also discussed the representative biological applications regarding these FGN-based bioactive architectures. Furthermore, the future perspectives and emerging challenges will also be highlighted. Due to the lack of comprehensive reviews in this emerging field, this review may catch great interest and inspire many new opportunities across a broad range of disciplines.
Inorganic Nanoparticles as Protein Mimics Kotov, Nicholas A.
Science (American Association for the Advancement of Science),
10/2010, Letnik:
330, Številka:
6001
Journal Article
Recenzirano
Inorganic nanoparticles coated with organic films can display surface chemistries that allow them to function like globular proteins.
Water-soluble inorganic nanoparticles (NPs) and globular proteins ...(GPs) might seem “as different as chalk and cheese,” especially in the interior. The chemical structure of GPs is usually exact and well-defined, whereas NPs are almost always formed as a mixture of sizes and variation of shapes. The complexity and dynamism of three-dimensional atomic organization inside the protein globules and related functionalities are not present in the impenetrable crystalline cores of NPs. However, NPs and GPs do reveal similarities in overall size, charge, and shape, and the exterior surfaces of NPs can be coated with organic functional groups similar to those exposed by GPs, which suggest that NPs could function as protein mimics. This option is attractive because NPs are usually cheaper and more stable than proteins, but can they actually display the same functionalities and achieve enough specificity to replace proteins?
Chiral Nanoceramics Fan, Jinchen; Kotov, Nicholas A.
Advanced materials (Weinheim),
10/2020, Letnik:
32, Številka:
41
Journal Article
Recenzirano
Odprti dostop
The study of different chiral inorganic nanomaterials has been experiencing rapid growth during the past decade, with its primary focus on metals and semiconductors. Ceramic materials can ...substantially expand the range of mechanical, optical, chemical, electrical, magnetic, and biological properties of chiral nanostructures, further stimulating theoretical, synthetic, and applied research in this area. An ever‐expanding toolbox of nanoscale engineering and self‐organization provides a chirality‐based methodology for engineering of hierarchically organized ceramic materials. However, fundamental discoveries and technological translations of chiral nanoceramics have received substantially smaller attention than counterparts from metals and semiconductors. Findings in this research area are scattered over a variety of sources and subfields. Here, the diversity of chemistries, geometries, and properties found in chiral ceramic nanostructures are summarized. They represent a compelling materials platform for realization of chirality transfer through multiple scales that can result in new forms of ceramic materials. Multiscale chiral geometries and the structural versatility of nanoceramics are complemented by their high chiroptical activity, enantioselectivity, catalytic activity, and biocompatibility. Future development in this field is likely to encompass chiral synthesis, biomedical applications, and optical/electronic devices. The implementation of computationally designed chiral nanoceramics for biomimetic catalysts and quantum information devices may also be expected.
Chiral nanoceramics are emerging as a remarkably active area of chiral research. It is still in its infant stage and is thus full of challenges and opportunities. Recent advances in the diversity of chemistries, geometries, and properties of chiral ceramic nanostructures are reviewed. An outlook of synthesis, computational methods, and emerging applications of chiral nanoceramics is presented.
Nonadditivity of nanoparticle interactions Batista, Carlos A. Silvera; Larson, Ronald G.; Kotov, Nicholas A.
Science (American Association for the Advancement of Science),
10/2015, Letnik:
350, Številka:
6257
Journal Article
Recenzirano
Odprti dostop
Understanding interactions between inorganic nanoparticles (NPs) is central to comprehension of self-organization processes and a wide spectrum of physical, chemical, and biological phenomena. ...However, quantitative description of the interparticle forces is complicated by many obstacles that are not present, or not as severe, for microsize particles (μPs). Here we analyze the sources of these difficulties and chart a course for future research. Such difficulties can be traced to the increased importance of discreteness and fluctuations around NPs (relative to μPs) and to multiscale collective effects. Although these problems can be partially overcome by modifying classical theories for colloidal interactions, such an approach fails to manage the nonadditivity of electrostatic, van der Waals, hydrophobic, and other interactions at the nanoscale. Several heuristic rules identified here can be helpful for discriminating between additive and nonadditive nanoscale systems. Further work on NP interactions would benefit from embracing NPs as strongly correlated reconfigurable systems with diverse physical elements and multiscale coupling processes, which will require new experimental and theoretical tools. Meanwhile, the similarity between the size of medium constituents and NPs makes atomic simulations of their interactions increasingly practical. Evolving experimental tools can stimulate improvement of existing force fields. New scientific opportunities for a better understanding of the electronic origin of classical interactions are converging at the scale of NPs.
Chiral self-assembled nanomaterials with biological applications have attracted great interest. In this study, DNA-driven gold-upconversion nanoparticle (Au-UCNP) pyramids were fabricated to detect ...intracellular microRNA (miRNA) in real time. The Au-UCNP pyramids are doubly optically active, displaying strong plasmonic circular dichroism (CD) at 521 nm and significant luminescence in 500–600 nm, and therefore can be monitored by both of them. CD will decrease while the luminescence intensity increases in the presence of miRNA. The experimental results show that the CD intensity had an outstanding linear range from 0.073 to 43.65 fmol/10 μgRNA and a limit of detection (LOD) of 0.03 fmol/10 μgRNA, whereas the luminescence intensity ranged from 0.16 to 43.65 fmol/10 μgRNA with a LOD of 0.12 fmol/10 μgRNA. These data indicate that the CD signal is much more sensitive to the concentration of miRNA than the luminescent signal, which is attributed to the strong CD intensity arising from the spin angular momentum of the photon interaction with chiral nanostructures and the plasmonic enhancement of the intrinsic chirality of DNA molecules in the pyramids. This approach opens up a new avenue to the ultrasensitive detection and quantification of miRNA in living cells.
Nanoscale building blocks of many materials exhibit extraordinary mechanical properties due to their defect-free molecular structure. Translation of these high mechanical properties to macroscopic ...materials represents a difficult materials engineering challenge due to the necessity to organize these building blocks into multiscale patterns and mitigate defects emerging at larger scales. Cellulose nanofibrils (CNFs), the most abundant structural element in living systems, has impressively high strength and stiffness, but natural or artificial cellulose composites are 3–15 times weaker than the CNFs. Here, we report the flow-assisted organization of CNFs into macroscale fibers with nearly perfect unidirectional alignment. Efficient stress transfer from macroscale to individual CNF due to cross-linking and high degree of order enables their Young’s modulus to reach up to 86 GPa and a tensile strength of 1.57 GPa, exceeding the mechanical properties of known natural or synthetic biopolymeric materials. The specific strength of our CNF fibers engineered at multiscale also exceeds that of metals, alloys, and glass fibers, enhancing the potential of sustainable lightweight high-performance materials with multiscale self-organization.
Terahertz circular dichroism (TCD) offers multifaceted spectroscopic capabilities for understanding the mesoscale chiral architecture and low-energy vibrations of macromolecules in (bio)materials
. ...However, the lack of dynamic polarization modulators comparable to polarization optics for other parts of the electromagnetic spectrum is impeding the proliferation of TCD spectroscopy
. Here we show that tunable optical elements fabricated from patterned plasmonic sheets with periodic kirigami cuts make possible the polarization modulation of terahertz radiation under application of mechanical strain. A herringbone pattern of microscale metal stripes enables a dynamic range of polarization rotation modulation exceeding 80° over thousands of cycles. Following out-of-plane buckling, the plasmonic stripes function as reconfigurable semi-helices of variable pitch aligned along the terahertz propagation direction. Several biomaterials, exemplified by an elytron of the Chrysina gloriosa, revealed distinct TCD fingerprints associated with the helical substructure in the biocomposite. Analogous kirigami modulators will also enable other applications in terahertz optics, such as polarization-based terahertz imaging, line-of-sight telecommunication, information encryption and space exploration.
Layer‐by‐layer (LbL) assembly is a widely used technique for the self‐assembly of layered nanocomposites from clay sheets, carbon nanotubes, graphene oxide, nanoparticles, and other materials. Other ...approaches for fabricating layered nanocomposites include vacuum‐assisted filtration and blade coating. They are simpler than LbL assembly, but they all introduce voids into the layered structure, thereby reducing the performance of the resulting nanocomposites. A team from Beihang University evaluated the void structure in Ti3C2Tx MXene composites and found that the fundamental problem with voids can be solved by the sequential nanoscale bonding of MXEne platelets with sodium carboxymethyl cellulose combined with covalent bridging with borate ions, thereby opening a new path to self‐assemble two‐dimensional platelets into continuous high‐performance layered nanocomposites.
Layered nanocomposites fabricated by techniques other than layer‐by‐layer assembly (e.g. vacuum‐assisted filtration and blade coating) contain voids in their structure, which reduces their performance. Cheng and co‐workers have now found that the problem of voids in Ti3C2Tx MXene composites can be solved by sequential bridging of MXEne platelets with sodium carboxymethyl cellulose combined with covalent bridging by borate ions.
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