Protein containers are suitable building blocks for bioinorganic materials. Here, we show that high concentrations of magnesium ions induce the formation of a unitary protein scaffold, whereas low magnesium concentration leads to a binary protein scaffold. The molecular interactions in the protein scaffold were characterized with X-ray crystallography to high resolution. We show that the unitary framework can be applied for the assembly of inorganic nanoparticles such as metal oxides into highly ordered bioinorganic structures. Our work emphasizes the structural tunability of protein-container-based materials, important for adjusting emerging properties of such materials.

We report on the swelling of a polymeric network in doubly thermoresponsive microgels. Silica-core double-shell and hollow double-shell microgels made of an inner poly(N-isopropylmethacrylamide) and an outer poly(N-isopropylacrylamide) shell are studied by exploiting the distinct temperature sensitivities of the polymers. The swelling states of the two shells can be tuned by temperature changes enabling three different swelling states: above, below, and between the distinct volume phase transition temperatures of the two polymers. This enables to investigate the effect of different constraints on the swelling of the inner network. Small-angle neutron scattering with contrast variation in combination with computer simulation discloses how the expansion of the inner shell depends on the material and swelling state of its constraints. In the presence of the stiff core, the microgels show a considerable interpenetration of the polymeric shells: the inner network expands into the outer deswollen shell. This interpenetration vanishes when the outer network is swollen. Furthermore, as predicted by our computer simulations, an appropriate choice of cross-linking density enables the generation of hollow double-shell nanocapsules. Here, the inner shell undergoes a push pull effect. At high temperature, the collapsed outer shell pushes the swollen inner network into the cavity. At lower temperature, the swelling of the outer network contrary pulls the inner shell back toward the external periphery.

AbstractDer isoelektronische und isostere Austausch ausgewählter CC‐ durch BN‐Einheiten in π‐konjugierten organischen Systemen (BN/CC‐Isosterie) hat sich als erfolgreiche Strategie zur Entwicklung BN‐dotierter polycyclischer aromatischer Kohlenwasserstoffe (PAKs) mit faszinierenden Eigenschaften und Funktionen erwiesen. Unlängst haben erste Beispiele die Nützlichkeit dieses Konzepts in der Polymerchemie gezeigt. Hier stellen wir die Synthese und Charakterisierung des ersten Poly(p‐phenyleniminoborans) vor. Dieses neue anorganisch‐organische Hybridpolymer kann als BN‐Analogon des bekannten Poly(p‐phenylenvinylens) (PPV) angesehen werden. Photophysikalische Untersuchungen am Polymer und einer Reihe von Modelloligomeren geben eindeutige Hinweise auf π‐Konjugation über die B=N‐Bindungen und eine Erweiterung der Konjugationslänge mit wachsender Kettenlänge. TD‐DFT‐Rechnungen verschaffen einen tieferen Einblick in die elektronische Struktur der neuen Materialien.

Substitution of selected CC units in p-conjugated organic frameworks by their isoelectronic and isosteric BN units (BN/CC isosterism) has proven to be a successful concept for the development of BN-doped polycyclic aromatic hydrocarbons (PAHs) with intriguing properties and functions. The first examples have just demonstrated the applicability of this approach to polymer chemistry. Herein, we present the synthesis and comprehensive characterization of the first poly(p-phenylene iminoborane). This novel inorganic-organic hybrid polymer can be regarded as a BN analogue of the well-known poly(p-phenylene vinylene) (PPV). Photophysical investigations on the polymer and a series of model oligomers provide clear evidence of some p-conjugation across the B=N bonds and extension of the conjugation path with increasing chain length. TD-DFT calculations provide deeper insight into the electronic structure of the new materials.

We have predicted using computer simulations and have detected with SAXS measurements that pH-sensitive core-shell polyampholyte microgels can form a dense layer ("skin") at the core-shell interface. The microgels have cationic core and neutral shell at low pH, whereas the core becomes neutral and the shell becomes anionic at high pH. The core and shell are oppositely charged at intermediate pH values. The layer formation is a result of the electrostatic complexation between oppositely charged subchains. We have studied microgels with different core-shell ratios and fractions of ionizable groups and analyzed radial distribution of polymer volume fraction and volume fractions of cationic and anionic groups. We have demonstrated that in many cases complexation of oppositely charged subchains (intermediate pH values) or swelling of charged core with neutral shell (low pH) are responsible for the formation of quasi-hollow structures with a loose core of strongly swollen subchains and dense shell of interpenetrating core- and shell-forming subchains. The most pronounced quasi-hollow structures are predicted in computer simulations for highly charged microgels. On the contrary, practically homogeneous swelling of the microgels is observed at high pH, when electrostatics-driven swelling of the anionic shell promotes swelling of the neutral core. All structures are colloidally stable due to the spatial segregation of the opposite charges. Therefore, the microgels can be useful as carriers for pH-controlled uptake, storage, and release of neutral guest molecules, which can be trapped within the microgel at low and intermediate pH and released at high pH.

Biomolecules can act as functional templates for the organization of inorganic particles. Here we use two protein containers, engineered with opposite surface charge, as building blocks for the construction of a new type of biohybrid material. Binary structures with crystalline order were obtained, adopting a tetragonal lattice. Moreover, the cavity of the engineered protein containers can be filled with inorganic nanoparticles. The controlled assembly of these protein-nanoparticle composites yields highly ordered binary nanoparticle superlattices as free-standing crystals, with up to a few hundred micrometers in size. Because the structure and lattice parameters of the protein-nanoparticle crystals are independent of their nanoparticle cargo, the binary protein material may serve as a generally applicable matrix for the assembly of a variety of nanoparticles types.

AbstractDer hohe Stellenwert anorganischer Hauptgruppenpolymere spiegelt sich wohl am deutlichsten in der wirtschaftlichen Bedeutung von Polysiloxanen (Siliconen) wider. Bororganische Materialien wie π‐konjugierte Organoboranpolymere oder BN‐dotierte polycyclische aromatische Kohlenwasserstoffe erregen derzeit große Aufmerksamkeit. Daher ist es verwunderlich, dass Poly(iminoborane) (PIBs), [BRNR′]n, die Stammverbindungen ungesättigter B‐N‐Polymere, die formal mit Polyacetylen isoelektronisch sind, bis heute noch nicht eindeutig charakterisiert worden waren. Hier stellen wir die Synthese und umfassende Charakterisierung eines linearen Oligo(iminoborans) vor, das aus einer Kette von durchschnittlich 12–14 BN‐Einheiten besteht. Durch unseren Syntheseansatz werden unerwünschte Nebenreaktionen, in denen Borazine gebildet werden, effektiv unterbunden. Unterstützende DFT‐ und TD‐DFT‐Rechnungen verschaffen einen tieferen Einblick in die Mikrostruktur und die elektronische Struktur des Oligomers.

The significance of inorganic main-group polymers is demonstrated most clearly by the commercial relevance of polysiloxanes (silicones). Organoboron-based materials such as π-conjugated organoborane polymers and BN-doped polycyclic aromatic hydrocarbons are currently attracting considerable attention. Surprisingly, poly(iminoborane)s (PIBs; [BRNR']n ), that is, the parent unsaturated BN polymers, which are formally isoelectronic to polyacetylene, have not been convincingly characterized thus far. Herein, we present the synthesis and comprehensive characterization of a linear oligo(iminoborane), which comprises a chain of 12-14 BN units on average. With our synthetic approach, unwanted side reactions that result in borazine formation are effectively suppressed. Supporting DFT and TD-DFT calculations provide deeper insight into the microstructure and the electronic structure of the oligomer.

We present an easy-to-use analytic toolbox for the calculation of short-time transport properties of concentrated suspensions of spherical colloidal particles with internal hydrodynamic structure, and direct interactions described by a hard-core or soft Hertz pair potential. The considered dynamic properties include self-diffusion and sedimentation coefficients, the wavenumber-dependent diffusion function determined in dynamic scattering experiments, and the high-frequency shear viscosity. The toolbox is based on the hydrodynamic radius model (HRM) wherein the internal particle structure is mapped on a hydrodynamic radius parameter for unchanged direct interactions, and on an existing simulation data base for solvent-permeable and spherical annulus particles. Useful scaling relations for the diffusion function and self-diffusion coefficient, known to be valid for hard-core interaction, are shown to apply also for soft pair potentials. We further discuss extensions of the toolbox to long-time transport properties including the low-shear zero-frequency viscosity and the long-time self-diffusion coefficient. The versatility of the toolbox is demonstrated by the analysis of a previous light scattering study of suspensions of non-ionic PNiPAM microgels [Eckert et al., J. Chem. Phys., 2008, 129, 124902] in which a detailed theoretical analysis of the dynamic data was left as an open task. By the comparison with Hertz potential based calculations, we show that the experimental data are consistently and accurately described using the Verlet-Weis corrected Percus-Yevick structure factor as input, and for a solvent penetration length equal to three percent of the excluded volume radius. This small amount of solvent permeability of the microgel particles has a significant dynamic effect at larger concentrations.

In this study, we have synthesised small aqueous zwitterionic microgels as model systems for amphoteric microgels. Zwitterions exhibit special behaviour due to defined distance between the opposite charges and provide a possibility to incorporate an identical number of positive and negative charges in microgels. Microgels decorated with zwitterionic groups exhibit unique properties compared with their analogues functionalized with separately incorporated oppositely charged co-monomers. In this work, two series of zwitterionic microgels with N-isopropylacrylamide (NIPAm) and N-vinylcaprolactam (VCL) as main monomers and various amounts of [3-(methacryloylamino)propyl]dimethyl(3-sulfopropyl) ammonium hydroxide (referred to as sulfobetaine) as zwitterionic co-monomer have been prepared. We investigated the effect of zwitterionic co-monomer content on the swelling behaviour, particle size, size distribution and volume phase transition temperature of the NIPAm-co-sulfobetaine microgels using various scattering methods, as dynamic and static light scattering and small-angle X-ray/neutron scattering. We found a decrease of particle size with the amount of sulfobetaine in the presence of sodium dodecylsulfate, which is contrary to results published earlier by Das et al. (Chem Mater 20: 7157–7163, 2008) for a similar system of zwitterionic microgels. The decrease of particle size is related to co-surfactant behaviour of sulfobetaine in mixtures with sodium dodecylsulfate. The incorporation of sulfobetaine also increases the polydispersity of the microgels and broadens the volume phase transition.

Spatially defined networks of 15 nm-sized DNA-fiinctionalized gold nanoparticles (DNA AuNPs) were studied using dynamic light scattering (DLS), small-angle Xray scattering (SAXS), as well as optical extinction spectroscopy (OES). We use a combination of these techniques with Monte Carlo simulations of pair-distance distribution function (PDDF) curves and generalized Mie theory simulations as well as in situ-transmission electron microscopy (in situ-TEM) to analyze the internal structure of the finite-size assemblies. The DLS data show that monodisperse, spherical networks with hydrodynamic radii of ca. 30 nm are found for reaction mixtures of complementarily functionalized DNA AuNPs between 1:15 and 1:20. Different interparticle distances within these assemblies are identified and quantified. By controlling the network morphology through selection of the reaction mixture, center-shell geometries are obtained. The number of shell-AuNPs surrounding each center-AuNP is determined from the SAXS data and Monte Carlo simulations. This number is quantified to be ca. 10, with the exact number depending on the linking DNA double strand. The optical spectra of the networks are found to be consistent with the structural properties. The structural information gained here enables a quantitative description of optical and other physical properties, which is expected to prove useful for the construction and application of such systems, for example, in drug release, gene regulation, or external-stimuli-responsive materials.

In this study, we compare the experimental static structure factors of concentrated solutions of amphoteric poly(N-isopropylacrylamide) (PNIPAM) microgels with those of the polydisperse hard-sphere model. We use zwitterionic microgels as model systems for amphoteric microgels with an equal amount of positive and negative charges located in a defined distance. Using small angle neutron scattering (SANS), we measure the static structure factors, S-M (q), of a series of zwitterionic microgels with increasing amount of zwitterion, including a reference sample of pure PNIPAM. The experimental S-M(q) is compared with predictions based on the Percus-Yevick approximation for hard spheres. We also compare with the PNIPAM reference sample measured for zwitterionic microgels. We find no significant influence of the zwitterionic comonomer on the effective pair potential. The PNIPAM and the zwitterionic microgels can be described by the hard-sphere model for smaller volume fractions phi(T) less than or similar to 0.4 only.

The influence of architecture on polymer interactions is investigated and differences between branched and linear copolymers are found. A comprehensive picture is drawn with the help of a fluorescence approach (using pyrene and 4HP as probe molecules) together with IR or NMR spectroscopy and X-ray/light scattering measurements. Five key aspects are addressed: (1) synergistic intramolecular complexation within miktoarm stars. The proximity of thermoresponsive poly(propylene oxide) (PPO) and poly(dimethylaminoethyl methacrylate) (PDMAEMA) within a miktoarm star leads to complexation between these weakly interacting partners. Consequently, the original properties of the constituents are lost, showing hydrophobic domains even at low temperatures, at which all homopolymers are water soluble. (2) Unimolecular micelles for miktoarm stars. The star does not exhibit intermolecular self-assembly in a large temperature range, showing unimers up to 55 °C. This behavior was traced back to a reduced interfacial tension between the PPO-PDMAEMA complex and water (PDMAEMA acts as a "microsurfactant"). (3) Unimolecular to multimolecular micelle transition for stars. The otherwise stable unimolecular micelles self-assemble above 55 °C. This aggregation is not driven by PPO segregation, but by collapse of residual PDMAEMA. This leads to micrometer-sized multilamellar vesicles stabilized by poly(ethylene oxide) (PEO). (4) Prevention of pronounced complexation within diblock copolymers. In contrast to the star copolymers, PPO and PDMAEMA adapt rather their homopolymer behavior within the diblock copolymers. Then they show their immanent LCST properties, as PDMAEMA turns insoluble at elevated temperatures, whereas PPO becomes hydrophobic below room temperature. (5) Two-step micellization for diblock copolymers. Upon heating of linear copolymers, the dehydration of PPO is followed by self-assembly into spherical micelles. An intermediate prevalence of unimolecular micelles is revealed in a small temperature window between PPO collapse and self-assembly of PEO-b-PPO. Also for PPO-b-PDMAEMA, PPO segregation prevails after initial weak complexation, leading to micelles with a PPO core. Considerable amounts of water are entrapped within the collapsed PDMAEMA domains above 55 °C (skin effect), preventing PPO-PDMAEMA complexation within precipitating PPO-b-PDMAEMA. Further, collapsed PDMAEMA is rather polar as sensed by pyrene and 4HP. In summary, advanced macromolecular architectures can lead to an unprecedented intramolecular self-assembly behavior, where internal complexation prevents intermolecular aggregation.

Photoacoustic imaging is based on the generation of ultrasound using laser irradiation. Recently, gold nanoparticles received a lot of attention due to their excellent suitability for use as contrast agents. For contrast agent analysis, Nd:YAG laser systems are commonly employed, but pulsed laser diodes, which are much smaller and cheaper, can be an attractive alternative. They emit significantly lower pulse energies, but fast averaging is feasible due to high repetition rates. Analysis of contrast agents using laser diodes suffers from vastly different properties of different laser diodes. Here, we present a calibration procedure to correct for some of these differences and enable comparison of results across multiple laser diodes. The calibration procedure is performed for analysis of nanoparticles ranging from diameters of 1 nm to 85 nm. The method is analyzed using two reference materials, Copper Chloride (CuCl2) and Copper Sulfate (CuSO4).

Photoacoustic (PA) imaging attracts a great deal of attention as an innovative modality for longitudinal, non-invasive, functional and molecular imaging in oncology. Gold nanoparticles (AuNPs) are identified as superior, NIR-absorbing PA contrast agents for biomedical applications. Until now, no systematic comparison of the optical extinction and PA efficiency of water-soluble AuNPs of various geometries and small sizes has been performed. Here spherical AuNPs with core diameters of 1.0, 1.4 and 11.2 nm, nanorods with longitudinal/transversal elongation of 38/9 and 44/12 nm and hollow nanospheres with outer/inner diameters of 33/19, 57/30, 68/45 and 85/56 nm were synthesized. The diode laser set-up with excitations at 650, 808, 850 and 905 nm allowed us to correlate the molar PA signal intensity with the molar extinction of the respective AuNPs. Deviations were explained by differences in heat transfer from the particle to the medium and, for larger particles, by the scattering of light. The molar PA intensity of 1.0 nm AuNPs was comparable to the commonly used organic dye methylene blue, and rapidly increased with the lateral size of AuNPs.

Microgels are intramolecular cross-linked macromolecules swollen by a solvent, e.g. water. Poly(N-isopropylacrylamide) (PNiPAM) undergoes a volume phase transition in water at 32°C [1]. The volume phase transition temperature (VPTT) can be adjusted by incorporating different comonomers or by charged comonomers leading to multi-sensitive microgels [2,3]. Incorporating zwitterionic comonomers make them fascinating systems due to the presence of oppositely charged groups in the polymer network [4]. Recently, we have prepared microgels based on NiPAM and various amounts of sulfobetaine as zwitterionic comonomer (figure 1).

SmallVolume 7, Issue 14 p. 1954-1960 Communication Glyco-DNA–Gold Nanoparticles: Lectin-Mediated Assembly and Dual-Stimuli Response Katrin G. Witten, Katrin G. Witten Institute of Inorganic Chemistry and JARA-FIT (Future Information, Technology), RWTH Aachen University, Landoltweg 1, 52074 Aachen, GermanySearch for more papers by this authorClaudia Rech, Claudia Rech Laboratoy for Biomaterials, Institute of Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Worringer Weg 1, 52074 Aachen, GermanySearch for more papers by this authorThomas Eckert, Thomas Eckert Institute of Physical Chemistry II, RWTH Aachen University, Landoltweg 2, 52074 Aachen, GermanySearch for more papers by this authorSamir Charrak, Samir Charrak Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, GermanySearch for more papers by this authorWalter Richtering, Walter Richtering Institute of Physical Chemistry II, RWTH Aachen University, Landoltweg 2, 52074 Aachen, GermanySearch for more papers by this authorLothar Elling, Corresponding Author Lothar Elling L.Elling@biotec.rwth-aachen.de Laboratoy for Biomaterials, Institute of Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Worringer Weg 1, 52074 Aachen, Germany Lothar Elling, Laboratoy for Biomaterials, Institute of Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Worringer Weg 1, 52074 Aachen, Germany. Ulrich Simon, Institute of Inorganic Chemistry and JARA-FIT (Future Information, Technology), RWTH Aachen University, Landoltweg 1, 52074 Aachen, GermanySearch for more papers by this authorUlrich Simon, Corresponding Author Ulrich Simon ulrich.simon@ac.rwth-aachen.de Institute of Inorganic Chemistry and JARA-FIT (Future Information, Technology), RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany Lothar Elling, Laboratoy for Biomaterials, Institute of Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Worringer Weg 1, 52074 Aachen, Germany. Ulrich Simon, Institute of Inorganic Chemistry and JARA-FIT (Future Information, Technology), RWTH Aachen University, Landoltweg 1, 52074 Aachen, GermanySearch for more papers by this author Katrin G. Witten, Katrin G. Witten Institute of Inorganic Chemistry and JARA-FIT (Future Information, Technology), RWTH Aachen University, Landoltweg 1, 52074 Aachen, GermanySearch for more papers by this authorClaudia Rech, Claudia Rech Laboratoy for Biomaterials, Institute of Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Worringer Weg 1, 52074 Aachen, GermanySearch for more papers by this authorThomas Eckert, Thomas Eckert Institute of Physical Chemistry II, RWTH Aachen University, Landoltweg 2, 52074 Aachen, GermanySearch for more papers by this authorSamir Charrak, Samir Charrak Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, GermanySearch for more papers by this authorWalter Richtering, Walter Richtering Institute of Physical Chemistry II, RWTH Aachen University, Landoltweg 2, 52074 Aachen, GermanySearch for more papers by this authorLothar Elling, Corresponding Author Lothar Elling L.Elling@biotec.rwth-aachen.de Laboratoy for Biomaterials, Institute of Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Worringer Weg 1, 52074 Aachen, Germany Lothar Elling, Laboratoy for Biomaterials, Institute of Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Worringer Weg 1, 52074 Aachen, Germany. Ulrich Simon, Institute of Inorganic Chemistry and JARA-FIT (Future Information, Technology), RWTH Aachen University, Landoltweg 1, 52074 Aachen, GermanySearch for more papers by this authorUlrich Simon, Corresponding Author Ulrich Simon ulrich.simon@ac.rwth-aachen.de Institute of Inorganic Chemistry and JARA-FIT (Future Information, Technology), RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany Lothar Elling, Laboratoy for Biomaterials, Institute of Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Worringer Weg 1, 52074 Aachen, Germany. Ulrich Simon, Institute of Inorganic Chemistry and JARA-FIT (Future Information, Technology), RWTH Aachen University, Landoltweg 1, 52074 Aachen, GermanySearch for more papers by this author First published: 08 June 2011 https://doi.org/10.1002/smll.201100492Citations: 11Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract The formation and properties of glyco-DNA–gold nanoparticles (NP) with a multivalent presentation of DNA-glyco ligands is presented. These particles are equipped with two reversible binding modes, which enable reversible dissociation by two independent external stimuli: temperature-induced DNA duplex melting and displacement of the DNA-glyco ligands from the carbohydrate recognition domains with free sugar. Citing Literature Supporting Information Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Filename Description smll_201100492_sm_suppl.pdf2.7 MB suppl Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. Volume7, Issue14Special Issue: C. A. Mirkin, 20 Years at NorthwesternJuly 18, 2011Pages 1954-1960 RelatedInformation

Fetuin-A/alpha(2)-HS glycoprotein is a major systemic inhibitor of unwanted calcium phosphate deposition in the soft tissue. Fetuin-A mediates the formation of initially similar to 100 nanometre sized colloidal protein-mineral particles, denoted as calciprotein particles. After a lag period, these particles rapidly grow to elongated particles of about twice the initial size. Similar particles can be generated with other acidic macromolecules as well. However, fetuin-A is more potent regarding activity and specificity of inhibition. Given the widely recognized physiological relevance of fetuin-A as an inhibitor of pathological mineralization both in vitro, in cells, in animals and in humans, and its ready availability in large quantities, fetuin-A is a prototypic model protein to investigate protein-calcium phosphate interactions and mineral colloid stabilization, respectively. Several studies have concentrated on the pathophysiological relevance and the structural details of particle formation and mineral ripening. The principles governing calciprotein particle formation and ripening are nevertheless poorly understood. Here we present a systematic and quantitative investigation by time-resolved dynamic light scattering of the three major parameters: fetuin-A concentration, mineral ion concentration and temperature. Changes in temperature had only a weak effect on calciprotein particle size. Increased mineral ion concentrations and especially increased fetuin-A concentration led to smaller particles. An increased temperature, mineral ion concentration and a reduced fetuin-A concentration, respectively, all accelerated the particle ripening process. Our investigation demonstrates that calciprotein particle formation and ripening are two separate and successive processes and that particle ripening follows Arrhenius law. Furthermore it provides concepts to control the particle size and stability.

Hierarchical superaggregates consisting of DNA-linked 14 nm AuNPs are synthesized and characterized by optical and scattering methods. Temperature changes, induced either thermally or photothermally, lead to a switching between specific sizes associated with superaggregates, primary networks, and individual nanoparticles. This could be of interest in the design of stimuli-responsive materials.