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Boron dipyrromethene dyes are highly attractive for image-guided photodynamic therapy. Nevertheless, their clinical breakthrough as theranostic agents is still obstructed by several limitations. Here, we report a series of strongly absorbing, heavy-atom-free, distyryl-BODIPY donor-acceptor dyads operating within the phototherapeutic window. Whereas diphenylamine and carbazole donors lead to strong fluorescence, dimethylacridine, phenoxazine, and phenothiazine units afford a decent fluorescence combined with the efficient formation of singlet oxygen. Dedicated photophysical analysis and quantum-chemical calculations are performed to elucidate the excited state dynamics responsible for the pronounced differences within the BODIPY series. Femtosecond transient absorption spectra reveal the nature of the excited state processes and the involvement of charge-transfer states in triplet formation. The authors thank Hasselt University and the University of Namur for continuing financial support (PhD scholarships JD and TC). BC and WM thank the Research Foundation -Flanders (FWO) for support through projects G087718N, G0D1521N, I006320N, GOH3816NAUHL, and the Scientific Research Community 'Supramolecular Chemistry and Materials' (W000620N). The calculations were performed on the computers of the 'Consortium des equipements de Calcul Intensif (CE ' CI)' (https://www.ceci-hpc.be), including those of the 'UNamur Technological Platform of High-Performance Computing (PTCI)' (https://www.ptci.unamur.be), for which we gratefully acknowledge financial support from the FNRS-FRFC, the Walloon Region, and the University of Namur (Conventions no. 2.5020.11, GEQ U.G006.15, U.G018.19, 1610468, and RW/GEQ2016). SD, AL, and MDD acknowledge support from the European Union's Horizon 2020 research and innovation program under grant agreement no. 871124 Laserlab-Europe.

The development of stimuli-responsive nanomaterials, that possess tailored functional properties for the release of specific compounds, is of particular interest. To this extent, controlling the release of molecules at the desired target is an important parameter to regulate chemical and/or biological reactions at a more profound level in a wide variety of applications. In the present work, we report on the development of dual-responsive thiourethane–urethane nanocapsules synthesized via an interfacial polymerization reaction executed at the droplet interface using the inverse miniemulsion technique. Evidence via morphological and controlled release investigations indicate that our nanocapsules are able to encapsulate hydrophilic compounds with high efficiency in their aqueous core and allow for its selective release upon exposure to UV light and the enzyme esterase. Moreover, we demonstrate the efficient encapsulation of the fragrance molecule geranyl acetate and the anticancer drug doxorubicin. For the latter, we demonstrate its apoptotic effect after being released in MCF 7 breast cancer cells. Overall, these nanocapsules can be used for a wide variety of applications where a selective release of the payload is desired.

Melatonin is a secretory product of the pineal gland that regulates circadian rhythm. It is also well-known for its anti-inflammatory and antioxidant properties against the damaging influences of reactive oxygen species. To improve its therapeutic efficacy, a new formulation with melatonin loaded in a stimuli-responsive polymeric nanocapsule has been prepared following an inverse mini-emulsion technique. The colloidal stability of the melatonin-loaded nanocapsules (MNCs) is studied using dynamic light scattering, while the morphology of these MNCs is characterized using various electron microscopies. These MNCs have an inner diameter of 80-120 nm with a cell wall thickness of 29 ± 11 nm. The emission band maximum for melatonin appears at 350 nm following excitation at 305 nm (quantum yield, Φ

Biobased and biodegradable polyhydroxyalkanoates (PHAs) have great potential as sustainable packaging materials. However, improvements in their processing and mechanical properties are necessary. In this work, the influence of melt processing conditions on the mechanical properties and microstructure of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is examined using a full factorial design of experiments (DoE) approach. We have found that strict control over processing temperature, mold temperature, screw speed, and cooling time leads to highly increased elongation at break values, mainly under influence of higher mold temperatures at 80 °C. Increased elongation of the moldings is attributed to relaxation and decreased orientation of the polymer chains together with a homogeneous microstructure at slower cooling rates. Based on the statistically substantiated models to determine the optimal processing conditions and their effects on microstructure variation and mechanical properties of PHBHHx samples, we conclude that optimizing the processing of this biopolymer can improve the applicability of the material and extend its scope in the realm of flexible packaging applications. ispartof: POLYMERS vol:13 issue:22 ispartof: location:Switzerland status: published

Fluorescent conjugated polymers formulated in nanoparticles show attractive properties to be used as bioimaging probes. However, their fluorescence brightness is generally limited by quenching phenomena due to interchain aggregation in the confined nanoparticle space. In this work, branched conjugated polymer networks are investigated as a way to enhance the photoluminescence quantum yield of the resulting conjugated polymer nanoparticles (CPNs). 1,3,5-Tribromobenzene and 2,2',7,7'-tetrabromo-9,9'-spirobifluorene are chosen as branching moieties and are added in 3 or 5 mol % to the poly(p-phenylene ethynylene) (PPE) conjugated polymer synthesis. Nanoparticles of all samples are prepared via the combined miniemulsion/solvent evaporation technique. The optical properties of the branched polymers in solution and in nanoparticle form are then compared to those of the linear PPE counterpart. The fluorescence quantum yield of the CPNs increases from 5 to 11% for the samples containing 1,3,5-tribromobenzene. Furthermore, when 5 mol % of either branching molecule is used, the one-photon fluorescence brightness doubles. The nanoparticles show low cytotoxicity in A549 human lung carcinoma cells up to a concentration of 100 μg/mL for 24 h. They also exhibit good particle uptake into cells and compatibility with two-photon imaging. ispartof: ACS BIOMATERIALS SCIENCE & ENGINEERING vol:5 issue:4 pages:1967-1977 ispartof: location:United States status: published

Fluorescent conjugated polymers formulated in nanoparticles show attractive properties to be used as bioimaging probes. However, their fluorescence brightness is generally limited by quenching phenomena due to interchain aggregation in the confined nanoparticle space. In this work, branched conjugated polymer networks are investigated as a way to enhance the photoluminescence quantum yield of the resulting conjugated polymer nanoparticles (CPNs). 1,3,5-Tribromobenzene and 2,2',7,7'-tetrabromo-9,9'-spirobifluorene are chosen as branching moieties and are added in 3 or 5 mol % to the poly(

Leishmaniasis, a vector-borne disease, is caused by intracellular parasite Leishmania donovani. Unlike most intracellular pathogens, Leishmania donovani are lodged in parasitophorous vacuoles and replicate within the phagolysosomes in macrophages. Effective vaccines against this disease are still under development, while the efficacy of the available drugs is being questioned owing to the toxicity for nonspecific distribution in human physiology and the reported drug-resistance developed by Leishmania donovani. Thus, a stimuli-responsive nanocarrier that allows specific localization and release of the drug in the lysosome has been highly sought after for addressing two crucial issues, lower drug toxicity and a higher drug efficacy. We report here a unique lysosome targeting polymeric nanocapsules, formed via inverse mini-emulsion technique, for stimuli-responsive release of the drug miltefosine in the lysosome of macrophage RAW 264.7 cell line. A benign polymeric backbone, with a disulfide bonding susceptible to an oxidative cleavage, is utilized for the organelle-specific release of miltefosine. Oxidative rupture of the disulfide bond is induced by intracellular glutathione (GSH) as an endogenous stimulus. Such a stimuli-responsive release of the drug miltefosine in the lysosome of macrophage RAW 264.7 cell line over a few hours helped in achieving an improved drug efficacy by 200 times as compared to pure miltefosine. Such a drug formulation could contribute to a new line of treatment for leishmaniasis. A. Das acknowledges SERB (India) Grants (CRG/2020/000492 and JCB/2017/000004) and DBT Grant (BT/PR22251/NNT/28/1274/2017) for supporting this research. N. Mukherjee acknowledges SERB (India) Grant PDF/2016/001437 and K. Das acknowledges the grant EMR/2015/001674 for supporting this research. Financial support from DST (DST/INSPIRE/03/2017/002477) is acknowledged by R.T. This manuscript bears CSMCRI registration no 7/2021. Pramanik, SK (corresponding author), CSIR Cent Salt & Marine Chem Res Inst, Bhavnagar 364002, Gujarat, India. Mukherjee, N (corresponding author), CSIR Indian Inst Chem Biol, Canc Biol & Inflammatory Disorder Div, Kolkata 700032, India. Chattopadhy, S (corresponding author), BITS Pilani, Pilani 403726, Goa, India. Das, A (corresponding author), Indian Inst Sci Educ & Res Kolkata, Mohanpur 741246, W Bengal, India. niladrizoology@gmail.com; sumitpramanik@csmcri.res.in; a.das@csmri.res.in

Polymer vesicles that mimic the function of cell membranes can be obtained through the self-assembly of amphiphilic block copolymers. The cell-like characteristics of polymer vesicles, such as the core-shell structure, semi-permeability and tunable surface chemistry make them excellent building blocks for artificial cells. However, the standard preparation methods for polymer vesicles can be time consuming, require special equipment, or have low encapsulation efficiency for large components, such as nanomaterials and proteins. Here, we introduce a new encapsulation strategy based on a simple double emulsification (SDE) approach which allows giant polymer vesicles to be formed in a short time and with basic laboratory equipment. The SDE method requires a single low molecular weight block copolymer that has the dual role of macromolecular surfactant and membrane building block. Giant polymer vesicles with diameters between 20-50 μm were produced, which allowed proteins and nanoparticles to be encapsulated. To demonstrate its practical application, we used the SDE method to assemble a simple artificial cell that mimics a two-step enzymatic cascade reaction. The SDE method described here introduces a new tool for simple and rapid fabrication of synthetic compartments.

Hypothesis Conjugated polymer nanoparticles (CNPs) have attracted considerable attention within bioimaging due to their excellent optical properties and biocompatibility. However, unspecific adsorption of proteins hampers their effective use as advanced bioimaging probes. Controlled methodologies made possible tailor-made functional poly(p-phenylene vinylene), enabling one-pot synthesis of CNPs containing functional surface groups. Hence, it should be feasible to PEGylate these CNPs to tune the uptake by cell lines representative for the brain without imparting their optical properties. Experiments CNPs consisting of the statistical copolymer 2-(5′-methoxycarbonylpentyloxy)-5-methoxy-1,4-phenylenevinylene and poly(2-methoxy-5-(3′,7′-dimethoxyoctyloxy)-1,4-phenylenevinylene) were fabricated by miniemulsion solvent evaporation technique. Surface carboxylic acid groups were used to covalently attach amine-terminated polyethylene glycol (PEG) of different molecular weights. We investigated the effect of grafting CNPs with PEG chains on their intrinsic optical properties, protein adsorption behavior and uptake by representative brain cell lines. Findings PEGylation did not affect the optical properties and biocompatibility of our CNPs. Moreover, a significant decrease in protein corona formation and unspecific uptake in central nervous system cell lines, depending on PEG chain length, was observed. This is the first report indicating that PEGylation does not affect the CNPs role as excellent bioimaging tools and can be adapted to tune biological interactions with brain cells.

Boron dipyrromethene (BODIPY) dyes represent a particular class within the broad array of potential photosensitizers. Their highly fluorescent nature opens the door for theragnostic applications, combining imaging and therapy using a single, easily synthesized chromophore. However, near-infrared absorption is strongly desired for photodynamic therapy to enhance tissue penetration. Furthermore, singlet oxygen should preferentially be generated without the incorporation of heavy atoms, as these often require additional synthetic efforts and/or afford dark cytotoxicity. Solutions for both problems are known, but have never been successfully combined in one simple BODIPY material. Here, we present a series of compact BODIPY-acridine dyads, active in the phototherapeutic window and showing balanced brightness and phototoxic power. Although the donor-acceptor design was envisioned to introduce a charge transfer state to assist in intersystem crossing, quantum-chemical calculations refute this. Further photophysical investigations suggest the presence of exciplex states and their involvement in singlet oxygen formation. The authors thank Hasselt University and the University of Namur for continuing financial support (PhD scholarships J.D. and T.C.). M.K., B.C., and W.M. thank the Research Foundation-Flanders (FWO) for support through project G087718N, Hercules project GOH3816NAUHL, and the Scientific Research Community (WOG) "Supramolecular Chemistry and Materials" (W000620N). The calculations were performed on the computers of the "Consortium des equipements de Calcul Intensif" (CECI) (http://www.ceci-hpc.be), including those of the "UNamur Technological Platform of High-Performance Computing" (PTCI) (http://www.ptci.unamur.be), for which we gratefully acknowledge the financial support from the FNRS-FRFC, the Walloon Region, and the University of Namur (Conventions No. 2.5020.11, GEQ U.G006.15, U.G018.19, 1610468, and RW/GEQ2016). Maes, W (corresponding author), UHasselt Hasselt Univ, Inst Mat Res IMO, Design & Synth Organ Semicond DSOS, B-3590 Diepenbeek, Belgium ; IMEC, Associated Lab IMOMEC, Wetenschapspk 1, B-3590 Diepenbeek, Belgium. wouter.maes@uhasselt.be

Molecularly imprinted polymers (MIPs) can selectively bind target molecules and can therefore be advantageously used as a low-cost and robust alternative to replace fragile and expensive natural receptors. Yet, one major challenge in using MIPs for sensor development is the lack of simple and cost-effective techniques that allow firm fixation as well as controllable and consistent receptor material distribution on the sensor substrate. In this work, a convenient method is presented wherein microfluidic systems in conjunction with in situ photo-polymerization on functionalized diamond substrates are used. This novel strategy is simple, efficient, low-cost and less time consuming. Moreover, the approach ensures a tunable and consistent MIP material amount and distribution between different sensor substrates and thus a controllable active sensing surface. The obtained patterned MIP structures are successfully tested as a selective sensor platform to detect physiological concentrations of the hormone disruptor testosterone in buffer, urine and saliva using electrochemical impedance spectroscopy. The highest added testosterone concentration (500 nM) in buffer resulted in an impedance signal of 10.03 ± 0.19% and the lowest concentration (0.5 nM) led to a measurable signal of 1.8 ± 0.15% for the MIPs. With a detection limit of 0.5 nM, the MIP signals exhibited good linearity between a 0.5 nM and 20 nM concentration range. Apart from the excellent and selective recognition offered by these MIP structures, they are also stable during and after the dynamic sensor measurements. Additionally, the MIPs can be easily regenerated by a simple washing procedure and are successfully tested for their reusability.

Conjugated polymers are versatile bio-imaging probes as their optical properties can be readily fine-tuned. In this manuscript, fluorescent conjugated polymer nanoparticles are fabricated using three different poly(p-phenylene ethynylene) (PPE) derivatives. The polymers have the same backbone but carry different side chains, i.e. regular octyloxy substituents, half of the octyloxy chains azide terminated, or azide functionalized tetraethylene glycol (TEG) moieties. The azide groups are specifically chosen to allow coupling of (bio)molecules to the surface of the particles using straightforward azide-alkyne click reactions, enabling different bioconjugation and targeting strategies. The influence of the functionalization pattern on the size and optical properties of the nanoparticles is studied using transmission electron microscopy, dynamic light scattering, UV-Vis absorption and fluorescence spectroscopy. The polymer containing the azide functionalized TEG chains affords larger particles, which can be attributed to hydration of the outer layer of the more hydrophilic polymer particles. However, this does not impact the fluorescence quantum yield. The two azide functionalized PPE particles exhibit the highest quantum yields (13%). Despite the presence of azide groups on two of the three materials, all particles are biocompatible and taken up by A549 human lung carcinoma cells. A proof of concept click reaction was performed as well.

Conjugated polymer nanoparticles exhibit very interesting properties for use as bio-imaging agents. In this paper, we report the synthesis of PCDTBT (poly([9-(1&rsquo, octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophene-diyl)) nanoparticles of varying sizes using the mini-emulsion and emulsion/solvent evaporation approach. The effect of the size of the particles on the optical properties is investigated using UV-Vis absorption and fluorescence emission spectroscopy. It is shown that PCDTBT nanoparticles have a fluorescence emission maximum around 710 nm, within the biological near-infrared &ldquo, optical window&rdquo, The photoluminescence quantum yield shows a characteristic trend as a function of size. The particles are not cytotoxic and are taken up successfully by human lung cancer carcinoma A549 cells. Irrespective of the size, all particles show excellent fluorescent brightness for bioimaging. The fidelity of the particles as fluorescent probes to study particle dynamics in situ is shown as a proof of concept by performing raster image correlation spectroscopy. Combined, these results show that PCDTBT is an excellent candidate to serve as a fluorescent probe for near-infrared bio-imaging.

Nanoparticles have been increasingly studied due to their unique properties. The deposition of uniform layers with these nanoparticles however is a crucial step in many of their applications. In this work, ultrasonic spray coating is the technique of choice as it is by design well-suited for the deposition of nano-suspension dispersions. The influence of different deposition parameters, ink composition and post-treatment are subject of study in this paper. It is shown in this work that (mass-) production of uniform nanoparticle layers is possible due to the narrow distribution of the droplet size and the deagglomeration of the particles during ultrasonic spray coating. It is also demonstrated that with ultrasonic spray coating it is possible to deposit an eco-friendly, water-based nanoparticle ink into layers with desired thickness and morphology.

Molecularly imprinted polymers (MIPs) in the micron and submicron scale based on the bifunctional cross-linker N,O-bismethacryloylethanolamine (NOBE) have been synthesized using bulk and miniemulsion polymerization, respectively. MIPs with distinct selectivity for the template testosterone were obtained. Colloidal MIP particles made using the miniemulsion technique have significant advantages compared to bulk MIP counterparts owing to their small size, homogeneity, and increased surface, as is demonstrated by optical batch rebinding studies using a nonimprinted polymer (NIP) as a negative control. Affinity and selectivity studies were also performed with the miniemulsion colloidal MIPs. These MIPs display largely increased imprint factors (6.8 vs 2.2) when compared to their bulk MIP counterparts. Further, selectivity studies by using analogue steroids show that colloidal MIPs also display a higher selectivity. In summary, miniemulsion MIPs show much better performance with respect to molecular recognition...

The development of functional nanocarriers with stimuli-responsive properties has advanced tremendously to serve biomedical applications such as drug delivery and regenerative medicine. However, the development of biodegradable nanocarriers that can be loaded with hydrophilic compounds and ensure its controlled release in response to changes in the surrounding environment still remains very challenging. Herein, we achieved such demands via the preparation of aqueous core nanocapsules using a base-catalyzed interfacial reaction employing a diisocyanate monomer and functional monomers/polymers containing thiol and hydroxyl functionalities at the droplet interface. pH-responsive poly(thiourethane–urethane) nanocarriers with ester linkages were synthesized by incorporating polycaprolactone diol, which is susceptible to hydrolytic degradation via ester linkages, as a functional monomer in the reaction formulation. We could demonstrate that by systematically varying the number of biodegradable segments, the morphology of the nanocarriers can be tuned without imparting the efficient encapsulation of hydrophilic payload (>85% encapsulation efficiency) and its transfer from organic to aqueous phase. The developed nanocarriers allow for a fast release of hydrophilic payload that depends on pH, the number of biodegradable segments and nanocarrier morphology. Succinctly put, this study provides important information to develop pH-responsive nanocarriers with tunable morphology, using interfacial reactions in the inverse miniemulsion process, by controlling the number of degradable segments to adjust the release profile depending on the type of application envisaged.

The lipid organization of microbubbles is important in many applications. By monitoring the photoselection and emission spectrum of the fluorescent probe Laurdan in perfluorobutane gas-filled DPPC microbubbles with a two-photon laser scanning microscope, we observed a transition to a more rigid lipid organization in 30 minutes to several hours. The authors thank IOF funding of Hasselt University and the support from Interuniversity Attraction Poles Program (IAP FS2 P7/05, Functional Supramolecular Systems) initiated by the (Belgian Science Policy Office). The authors thank the province of Limburg for the support through IMPTECHNO. A. E. acknowledges support by European Commission funding under Horizon 2020 programme, FET-OPEN project AMPHORA, grant agreement 766456. S. S. is an SB PhD fellow at the Research Foundation Flanders (FWO). The authors are grateful to Dr R. Paesen for the development of the polarization control unit in the confocal laser scanning microscope. The authors thank H. Penxten for the technical assistance with the fluorescence spectroscopy measurements.

It is now well-established that the surface chemistry and “stealth” surface functionalities such as poly(ethylene glycol) (PEG) chains of nanocarriers play an important role to decrease unspecific protein adsorption of opsonizing proteins, to increase the enrichment of specific stealth proteins, and to prolong the circulation times of the nanocarriers. At the same time, PEG chains are used to provide colloidal stability for the nanoparticles. However, it is not clear how the chain length and density influence the unspecific and specific protein adsorption keeping at the same time the stability of the nanoparticles in a biological environment. Therefore, this study aims at characterizing the protein adsorption patterns depending on PEG chain length and density to define limits for the amount of PEG needed for a stealth effect by selective protein adsorption as well as colloidal stability during cell experiments. PEG chains are introduced using the PEGylated Lutensol AT surfactants, which allow easy modification of the nanoparticle surface. These findings indicate that a specific enrichment of stealth proteins already occurs at low PEG concentrations; for the decrease of unspecific protein adsorption and finally the colloidal stability a full surface coverage is advised.

Conjugated polymer nanoparticle systems have gained significant momentum in the bioimaging field on account of their biocompatibility and outstanding spectroscopic properties. Recently, new control procedures have spawned custom-built functional poly(p-phenylene vinylene) (PPV). These facilitate the one-pot synthesis of semiconducting polymer NPs with incorporated surface functional groups, an essential feature for advanced biomedical applications. In this work, nanoparticles (NPs) of different sizes are synthesized consisting of the statistical copolymer CPM-co-MDMO-PPV with monomer units 2-(5'-methoxycarbonylpentyloxy)-5-methoxy-1,4-phenylenevinylene (CPM-PPV) and poly(2-methoxy-5-(3',7'-dimethoxyoctyloxy)-1,4-phenylenevinylene) (MDMO-PPV). To monitor potential implications of switching from a commonly used homopolymer to copolymer system, MDMO-PPV NPs were prepared as a control. The versatile combination of the miniemulsion and solvent evaporation method allowed for an easy adaptation of the NP size. Decreasing the diameter of functional PPV-based NPs up to 20 nm did not significantly affect their optical properties nor the biocompatibility of the bioimaging probe, as cell viability never dropped below 90%. The quantum yield and molar extinction coefficient remained stable at values of 1-2% and 10(6) M-1 cm(-1) respectively, indicating an excellent fluorescence brightness. However, a threshold was observed to which the size could be lowered without causing irreversible changes to the system. Cell uptake varied drastically depended on size and material choice, as switching from homo- to copolymer system and lowering the size significantly increased NP uptake, These results clearly demonstrate that adjusting the size of functional PPV-based NPs can be achieved easily to a lower limit of 20 nm without adversely affecting their performance in bioimaging applications. The Authors thank the Agency for Innovation by Science and Technology in Flanders, Belgium for funding.

The use of photo-induced copper-mediated radical polymerization (photoCMP) to synthesize mixed acrylate/methacrylate (methyl acrylate, MA and methyl methacrylate, MMA) block copolymers is investigated. Reactions in which only one type of ligand (Me6TREN) is used lead to unsuccessful outcomes of polymerization due to a mismatch in reactivity of the two monomers. A ligand exchange to PMDETA for methacrylate is required to obtain good block structures. Due to insufficient re-initiation of polyacrylates, methyl methacrylate needs to be polymerized first, before acrylate can be added for chain extension. A halogen exchange with CuCl is found to be beneficial to increase the re-initiation behaviour of the polyacrylate with respect to the acrylate chain propagation, but inherently compromises the livingness of the polymerization. Successful synthesis of block copolymers is only observed when the PMMA block is polymerized first and if all PMDETA ligand and residual monomer are removed prior to acrylate chain extension. The batch-type photoreactions are then transferred to a continuous flow tubular photoreactor, which leads to a significant acceleration of polymerizations, concomitant reduction in product dispersity and largely simplified block copolymer synthesis conditions.

With recent advances in the field of diagnostics and theranostics, liposomal technology has secured a fortified position as a potential nanocarrier. Specifically, radiation/photo-sensitive liposomes containing photo-polymerizable cross-linking lipids are intriguing as they can impart the vesicles with highly interesting properties such as response to stimulus and improved shell stability. In this work, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphoethanolamine (DTPE) is used as a photo-polymerizable lipid to form functional hybrid-liposomes as it can form intermolecular cross-linking through the diacetylenic groups. Hybrid-liposomes were formulated using mixtures of DTPE and saturated lipids of different chain lengths (dipalmitoylphosphatidylcholine (DPPC) and dimirystoilphosphatidylcholine (DMPC)) at different molar ratios. The physico-chemical characteristics of the liposomes has been studied before and after UV irradiation using a combination of techniques: DSC, QCM-D and solid-state NMR. The results signify the importance of a subtle modification in alkyl chain length on the phase behavior of the hybrid-liposomes and on the degree of crosslinking in the shell. The authors thank IOF funding of Hasselt University and the support from BELSPO via IAP Programme (P7/05). The authors are thankful to Prof. M. Van Bael for the access to the DLS device and to Martine Vanhamel for DSC measurements. A.E. was supported by a FWO (Research Foundation Flanders) post-doctoral fellowship.

We report the controlled preparation of water processable nanoparticles (NPs) employing the push-pull polymer PCDTBT and the fullerene acceptor PC71BM in order to enable solar cell processing using eco-friendly solvent (i.e. water). The presented method provides the possibility to separate the formation of the active layer blend and the deposition of the active layer into two different processes. For the first time, the benefits of aqueous processability for the high-potential class of push-pull polymers, generally requiring high boiling solvents, are made accessible. With our method we demonstrate excellent control over the blend stoichiometry and efficient mixing. Furthermore, we provide visualization of the nano morphology of the different NPs to obtain structural information down to similar to 2 nm resolution using advanced analytical electron microscopy. The imaging directly reveals very small compositional demixing in the PCDTBT:PC71BM blend NPs, in the size range of about

Photoinitiated copper-mediated radical polymerization offers an one-pot and time efficient method of preparing a decablock copolymer PMA-PtBA-PMA-PDEGA-PMA-PtBA-PMA-PDEGA-PnBA-PDEGA with an overall molecular weight of 8500 g·mol–1. The molecular weight is in close agreement with theoretical expectations and significantly narrow dispersities (Đ = 1.1–1.17) are achieved for the various block extensions. The tert-butyl group of the decadeblock was deprotected to form PMA-PAA-PMA-PDEGA-PMA-PAA-PMA-PDEGA-PnBA-PDEGA. The deprotection is confirmed by the disappearance of tert-butyl signal and the loss of molecular weight investigated by 1H NMR and SEC, respectively. The carboxylic group of PAA is protonated in acidic solution (water insoluble) and deprotonated in basic solution (water-soluble). This enables a conformational change of PMA-PAA-PMA-PDEGA-PMA-PAA-PMA-PDEGA-PnBA-PDEGA in water/ethanol mixture (80/20%v/v), as is demonstrated by a turbid solution at pH 2 and transparent solutions at pH 10.

The synthesis of amphiphilic rod-coil block copolymers with a poly( p -phenylene vinylene) (PPV) rod-like block using a Click chemistry approach is investigated and a facile reaction pathway towards poly( p -phenylene vinylene)- block -poly(ethylene glycol) (PPV- b -PEG) block copolymers is presented. To reach this aim, an alkyne-functionalized PPV block (synthesized from anionic sulfinyl precursor route polymerization) was synthesized and subsequently coupled to azide-functionalized poly(ethylene glycol) of different lengths. Self-assembly of these materials in aqueous solution demonstrate successful micelle formation with core–shell morphology and different sizes for these PPV- b -PEG block copolymers as is confirmed by TEM and DLS measurements respectively.

Copolymerization of the cyclic ketene acetal 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) with methyl methacrylate (MMA) is studied with respect to its copolymerization parameters and the suitability to control BMDO/MMA copolymerizations via the reversible addition-fragmentation chain transfer (RAFT) technique to obtain linear and 4-arm star polymers. BMDO shows disparate copolymerization behavior with MMA and r1 = 0.33 ± 0.06 and r2 = 6.0 ± 0.8 have been determined for polymerization at 110 °C in anisole from fitting copolymer composition vs. comonomer feed data to the Lewis–Mayo equation. Copolymerization of the two monomers is successful in RAFT polymerization employing a trithiocarbonate control agent. As desired, polymers contain only little amount of polyester units stemming from BMDO units and preliminary degradation experiment show that the polymer degrades slowly, but steadily in aqueous 1 M NaOH dispersion. Within ten days, the polymers are broken down to low molecular weight segments from an initial molecular weight of Mn = 6000 g mol−1. Star (co)polymerization with an erythritol-based tetra-functional RAFT agent following the Z-group approach proceeds efficiently and polymers with a number-average molecular weight of 10,000 g mol−1 are readily obtained that degrade in similar manner as the linear copolymer counterparts. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1633–1641

Molecularly imprinted polymers (MIPs) are synthetic receptors that are able to specifically bind their target molecules in complex samples, making them a versatile tool in biosensor technology. The combination of MIPs as a recognition element with quartz crystal microbalances (QCM-D with dissipation monitoring) gives a straightforward and sensitive device, which can simultaneously measure frequency and dissipation changes. In this work, bulk-polymerized L-nicotine MIPs were used to test the feasibility of L-nicotine detection in saliva and urine samples. First, L-nicotine-spiked saliva and urine were measured after dilution in demineralized water and 0.1× phosphate-buffered saline solution for proof-of-concept purposes. L-nicotine could indeed be detected specifically in the biologically relevant micromolar concentration range. After successfully testing on spiked samples, saliva was analyzed, which was collected during chewing of either nicotine tablets with different concentrations or of smokeless tobacco. The MIPs in combination with QCM-D were able to distinguish clearly between these samples: This proves the functioning of the concept with saliva, which mediates the oral uptake of nicotine as an alternative to the consumption of cigarettes. ispartof: Analytical and Bioanalytical Chemistry vol:405 issue:20 pages:6479-6487 ispartof: location:Germany status: published

A rapid and facile route allows the self-assembly of precursor micelles loaded with metal salts on an unprecedented short timescale. Micellar arrays can then be transformed into high-quality (metal or metal oxide) nanoparticle arrays. This promising route offers functionalization of surfaces by nanomaterials on industrially relevant timescales. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. ispartof: Angewandte Chemie - International Edition vol:52 issue:37 pages:9709-9713 ispartof: location:Germany status: published

We wish to thank H. Penxten for fluorescence spectroscopy, Dr. J. D'Haen for TEM, C. Willems and J. Baccus for technical assistance. T.J. is grateful for an Odysseus grant from the Funds for Scientific Research Flanders (FWO).

The efficient functionalization of poly(divinylbenzene) (polyDVB) nanoparticles via Paterno–Buchi type [2 + 2]-photocycloadditions is described. Initially polyDVB nanoparticles with high density of alkene groups on the surface are synthesized via radical miniemulsion polymerization. Subsequently, UV-induced [2 + 2]-photocycloadditions with different functionalized aldehydes have been performed on the surface under mild and catalyst-free conditions. In order to show the versatility and the accessibility towards incorporation of different functionalities with this strategy, surface modifications were carried out with ATRP initiators and NHS esters for bioconjugation, respectively. Finally, these photofunctionalized nanoparticles were grafted with poly(butyl acrylate) or with gold-labeled antibodies to prove the success of the reactions. PolyDVB nanoparticles before and after photofunctionalization are characterized by X-ray photoelectron spectroscopy (XPS), electron microscopy (SEM and TEM) and ATR-FTIR spectroscopy. Results show that the photoconjugation route is highly efficient and grafting densities of 4 to 5 molecules per nm2 on the entire surface of the particles are achieved.

ObjectivesIn this study, we investigate in human cervical epithelial HeLa cells the intracellular dynamics and the mutual interaction with the organelles of the poly-l-lactic acid nanoparticles (PLLA NPs) carrying the naturally occurring hydrophobic photosensitizer hypericin.MethodsTemporal and spatiotemporal image correlation spectroscopy was used for the assessment of the intracellular diffusion and directed motion of the nanocarriers by tracking the hypericin fluorescence. Using image cross-correlation spectroscopy and specific fluorescent labelling of endosomes, lysosomes and mitochondria, the NPs dynamics in association with the cell organelles was studied. Static colocalization experiments were interpreted according to the Manders' overlap coefficient.Key findingsNanoparticles associate with a small fraction of the whole-organelle population. The organelles moving with NPs exhibit higher directed motion compared to those moving without them. The rate of the directed motion drops substantially after the application of nocodazole. The random component of the organelle motions is not influenced by the NPs.ConclusionsImage correlation and cross-correlation spectroscopy are most appropriate to unravel the motion of the PLLA nanocarrier and to demonstrate that the rate of the directed motion of organelles is influenced by their interaction with the nanocarriers. Not all PLLA-hypericin NPs are associated with organelles.

Conjugated polymers have attracted significant interest in the bioimaging field due to their excellent optical properties and biocompatibility. Tailor-made poly(p-phenylenevinylene) (PPV) conjugated polymer nanoparticles (NPs) are in here described. Two different nanopartide systems using poly[2-methoxy-5-(3',7'-dimethoxyoctyloxy)-1,4-phenylenevinylene](MDMO-PPV) and a functional statistical copolymer 2-(5'methoxycarbonylpentyloxy) -5-m e th oxy- 1,4-ph enyl en evinyl e n e (CPM-MDMO-PPV), containing ester groups on the alkoxy side chains, were synthesized by combining miniemulsion and solvent evaporation processes. The hydrolysis of ester groups into carboxylic acid groups on the CPM-MDMO-PPV NPs surface allows for biomolecule conjugation. The NPs exhibited excellent optical properties with a high fluorescent brightness and photostability. The NPs were in vitro tested as potential fluorescent nanoprobes for studying cell populations within the central nervous system. The cell studies demonstrated biocompatibility and surface charge dependent cellular uptake of the NPs. This study highlights that PPV-derivative based particles are a promising bioimaging probe and can cater potential applications in the field of nanomedicine. The Authors thank the Agency for Innovation by Science and Technology in Flanders (IWT) and BOF UHasselt for funding. Support for confocal microscopy was given by Prof. Dr. Marcel Ameloot. Cells were kindly provided by Dr. Annelies Bronckaers, Drs. Jo Mailleux, and Dr. Jasmine Vanmol. Technical support was given by Huguette Penxten and Christel Bocken. M.P. and N.Z. are grateful for funding from the IWT (Agentschap voor Innovatie door Wetenschap en Technologie). A.E. is a FWO (Research Foundation Flanders) postdoctoral fellow. T.J. is grateful for funding from FWO in the form of an Odysseus grant. Additional support from BELSPO in the form of the interuniversity attraction pole (IAP) Program P7/05: Functional Supramolecular Systems is kindly acknowledged.

In the last few years, the advent of metal halide perovskite solar cells has revolutionized the prospects of next-generation photovoltaics. As this technology is maturing at an exceptional rate, research on its environmental impact is becoming increasingly relevant.

The authors report on the effect of ionic strength on the formation of supported vesicle layers of anionic phospholipids 1,2-dimyristoyl-sn-glycero-3-phospho-rac-glycerol (DMPG) and dimyristoylphosphatidylserine (DMPS) onto gold. Using quartz crystal microbalance with dissipation monitoring the authors show that vesicleadsorption is mainly governed by NaCl concentration, reflecting the importance of electrostatic interactions in anionic lipids, as compared to zwitterionic 1,2-dimyristoyl-sn-glycero-3-phosphocholine. At low ionic strength, low or no adsorption is observed as a result of vesicle–vesicle electrostatic repulsion. At medium ionic strength, the negative charges of DMPG and DMPS are screened resulting in larger adsorption and a highly dissipative intact vesicle layer. In addition, DMPS exhibits a peculiar behavior at high ionic strength that depends on the temperature of the process. A.E. is a FWO postdoctoral fellow. S.N., F.U.R., and P.L.-P. acknowledge the financial support from the FWO Odysseus Program under G0D0115N Project. The authors acknowledge Marlies K. Van Bael for the use of the DLS device.

Investigation of the temporal and spatial behavior of nanoparticles (NPs) within the intracellular environment provides insight in NP delivery routes, biointeractions, and subcellular targeting. Here, we investigate the delivery of the naturally occurring hydrophobic photosensitizer hypericin in human cervical epithelial HeLa cells and human primary dendritic cells (DCs) by using biocompatible and biodegradable poly l -lactic acid (PLLA) NPs. Temporal and spatiotemporal image correlation spectroscopy (TICS and STICS) is used for the assessment of the intracellular diffusion and/or flow velocity of hydrophobic hypericin (delivered by encapsulation within PLLA NPs). As the physicochemical nature of hypericin is crucial for cellular studies, for comparison, the hydrophilic form of hypericin [polyvinylpyrrolidone-hypericin (PVP-Hyp)] is also studied. By using spatiotemporal image cross-correlation spectroscopy (STICCS) and specific fluorescent labeling of early endosomes, late endosomes, lysosomes, and mitochondria, the directed motion of the NPs and PVP-Hyp in association with the organelles is investigated. The NPs and PVP-Hyp associate with a small fraction of the whole organelle population. STICCS suggests that the directed motion of the organelles is influenced by their interaction with the NPs and photosensitizer.

Intensive development of organometal halide perovskite solar cells has lead to a dramatic surge in power conversion efficiency up to 20%. Unfortunately, the most efficient perovskite solar cells all contain lead (Pb), which is an unsettling flaw that leads to severe environmental concerns and is therefore a stumbling block envisioning their large-scale application. Aiming for the retention of favorable electro-optical properties, tin (Sn) has been considered the most likely substitute. Preliminary studies have however shown that Sn-based perovskites are highly unstable and, moreover, Sn is also enlisted as a harmful chemical, with similar concerns regarding environment and health. To bring more clarity into the appropriateness of both metals in perovskite solar cells, we provide a case study with systematic comparison regarding the environmental impact of Pb- and Sn-based perovskites, using zebrafish (Danio Rerio) as model organism. Uncovering an unexpected route of intoxication in the form of acidification, it is shown that Sn based perovskite may not be the ideal Pb surrogate. This work was financially supported by the Bijzonder Onderzoeksfonds (BOF, Hasselt University) and the Fonds voor Wetenschappelijk Onderzoek (FWO) within the Odysseus program. B.C. and A.E. are postdoctoral research fellows of FWO. D.D.T. is a doctoral fellow of Wallonie-Bruxelles International (WBI), M.M. is a “Chercheur Qualifié du F.N.R.S.”. We wish to thank the GIGA-R zebrafish facility for providing zebrafish adults for spawning, and Bart Ruttens (Hasselt University) for supporting the XRD measurements. We are also grateful to Prof. David Cahen and his research group (Weizmann Institute of Science) for fruitful discussions.

The study of protein adsorption on solid surfaces is interesting for theoretical and practical bio-analytical sensing applications. In this work we combine electrochemical impedance spectroscopy, enzyme linked immunosorbent assay, and fluorescence microscopy with thin boron doped nanocrystalline diamond films to address and study the adsorption behavior of globular proteins (antibodies) on hydrophobic and hydrophilic diamond surfaces. A powerful combination of time resolved impedance spectroscopy and data modeling with equivalent circuits allow a detailed insight in the protein behavior at an interface. It is found that hydrogenated diamond is greatly favorable for impedimetric read-out but causes slight conformational loss of the protein structure and therefore also its biological activity. The oxidized surface allows faster adsorption and a high biological activity but results in smaller impedimetric response. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. ispartof: Physica Status Solidi A, Applications and Materials Research vol:208 issue:9 pages:2093-2098 status: published

The controlled synthesis of organic–inorganic hybrid particles with selective morphology using polymeric nanoparticles as templates offers an effective biomimetic route to design composite materials with interesting properties for various potential applications. In this study, the formation of hybrid particles via the bio-inspired mineralization of calcium phosphate (CaP) on the surface of different surface-functionalized polymeric nanoparticles is reported. The versatile miniemulsion polymerization is used to prepare different surface functionalized nanoparticles with covalently bound carboxylic acid and phosphonic acid surface-functionalities. Functional comonomers with varying hydrophilicity like acrylic acid (AA), vinylphosphonic acid (VPA), and vinylbenzylphosphonic acid (VBPA) are employed for the copolymerization with styrene. The influence of different functional groups at different pH on the crystal phase and morphology of the calcium phosphate phase in the hybrid nanoparticles is analyzed in detail by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron as well as X-ray diffraction (ED and XRD) techniques. The calcium ion binding affinity of different surface functional groups at varying loading conditions is studied using calcium ion selective electrode to shed light on the mineralization kinetics as well as on the interfacial chemistry involved between the complexing ions and the functional groups on the particle surface. The CaP/polymer hybrid particles with well-defined crystal phases and morphologies offering varying surface topographies are interesting candidates for cell adhesion and proliferation studies for potential tissue engineering applications. They could be used as bone fillers, building blocks for the nucleation, and the growth of new bone material or implant coatings to reduce the immune response.

The use of polymeric nanoparticles as templates for producing inorganic materials is an intriguing approach as it offers the feasibility of synthesizing hybrid organic-inorganic functional materials for a broad spectrum of applications ranging from optoelectronics to biomedicine. The concept of using polymer nanoparticles as templates to produce hybrid materials has several advantages. On the one hand, the entire geometry of the nanoparticle can be used as a confined nano-environment to let the inorganic material grow inside the particle. On the other hand, the high surface area of nanoparticle can be exploited to let the inorganic material grow on the outside surface of the particles. One such application is presented here, in which polymer nanoparticles were used as biomimetic template to produce composite nanoparticles made of the bone mineral hydroxyapatite (HAP). The synthesized hybrid particle has a great potential to be used as regenerative filler or as scaffold for nucleation and growth of new bone material. In addition to be applied as coatings on implants, these nanoparticles also offer the feasibility of being injected directly into the damaged part or administered intravenously with functionalization. Within this overview, we will mainly focus on different polymer nanoparticles obtained by the miniemulsion technique and the different possibilities for them to be used as templates for the biomimetic mineralization of calcium phosphate in the aqueous phase.

The use of polymeric nanoparticles as templates for producing inorganic materials is an intriguing approach, as it offers the feasibility of synthesizing organic/inorganic hybrid materials for several interesting applications. Here, polymeric nanoparticles synthesized via the miniemulsion process are employed as templates for biomimetic mineralization of hydroxyapatite in the aqueous phase. The versatile miniemulsion technique allows the fabrication of surface-functionalized polymeric nanoparticles with varying amounts of surface-bound functional groups by use of different types of surfactants. Hybrid nanoparticles were formed by performing crystallization outside on the surface of the polymer nanoparticles by varying the amount of surface functional groups and were studied by high-resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). These hydroxyapatite/polymer hybrid nanoparticles have great potential to be used as filler or as scaffold fo...

Here, we report a novel biomimetic strategy to synthesize hydroxyapatite (HAP) inside of crosslinked gelatin nanoparticles, which serve as a nanoenvironment for crystal growth in the aqueous phase. The synthesis of gelatin nanoparticles with the inverse miniemulsion technique is very intriguing because of the flexibility offered by the technique in tailoring the properties of the gelatin nanoparticles. It can be shown that the nanoenvironment promotes a different growth environment for the crystal because of the confinement inside the particle. The formation of HAP inside the particles follows Ostwald's rule of stages. At first an amorphous phase is formed, which itself has a great potential to be used as a resorbable bone substitute. This further transforms into single crystalline HAP via an octacalcium phosphate intermediate. The solution-mediated transformation into the HAP phase without any calcination step is studied in detail using transmission electron microscopy (TEM) and X-ray diffraction (XRD) measurements.

A convenient synthetic route based on the concept of nanoreactors using the versatility of the miniemulsion technique to synthesize glutardialdehyde cross-linked gelatin nanoparticles with tailored properties is reported. It is demonstrated that, independent of the molecular weight distribution of the gelatin used, stable nanoparticles can be produced with a small amount of surfactant. The amount of gelatin and the cross-linking degree in the particle can be well controlled. Different types of gelatin have been used without purification or fractionation. The stability of the dispersion, particle size, and the efficiency of cross-linking have been studied. Such nanoparticles with varying gelatin concentration and cross-linking density have high potential to be used for drug delivery applications, as nanoenvironment or template for synthesizing inorganic materials.

At the ultimate limit of magnetic recording, suitable storage media will consist of nanometer-sized entities, each of which will carry one bit of information. Materials with a high magnetocrystalline anisotropy energy are required to guarantee thermal stability of the ferromagnetic state at realistic operating temperatures. The face-centered tetragonal (fct) L10 FePt alloy belongs to the promising class of materials that offer the perspective of storing one magnetic bit per nanoparticle. Widespread activities have therefore arisen worldwide, targeting novel strategies for both the synthesis of suitable magnetic nanostructures and their organization into superlattices by means of parallel processes. Here, we present a new approach for the synthesis of size-selected L10 FePt nanoparticles based on the self-organization of spherical micelles formed by diblock copolymers, thereby significantly extending a previous technique to produce large-scale arrays of elemental nanoparticles. Our approach overcomes the typical drawbacks of the current colloidal routes towards densely packed arrays of ferromagnetic FePt nanoparticles while still guaranteeing areal densities exceeding 1 Tbits inch (1 inch≈ 2.54 cm). Since the first presentation of magnetic data-storage devices five decades ago, the areal density of digital information has increased by eight orders of magnitude to reach values of about 200 Gbits inch, as found in present hard disk drives. A few years ago, an efficient method was developed to synthesize FePt nanoparticles on the basis of wet-chemical synthesis (hereafter referred to “colloidal”), which involves particle stabilization by an organic-ligand shell. The significant advantage of this approach, allowing a simple preparation of densely packed 2D nanoparticle arrays from corresponding particle solutions, is, however, compensated by some serious drawbacks related to the thin ligand shell (1–3 nm) which serves as a spacer between the nanoparticles. As a consequence of the resulting small interparticle distance, the nanoparticles exhibit a strong tendency to aggregate during heat treatments. Thermal annealing at 500–600 °C is, however, generally required in order to transform the assynthesized, chemically disordered (Fe and Pt atoms randomly distributed over the lattice sites) face-centered cubic (fcc) structure, which results in superparamagnetic behavior, into the magnetically attractive L10 phase. Furthermore, undesirable collective magnetic dynamics arise at such small interparticle distances through dipolar coupling; collective modes, however, are clearly at odds with the idea of storing magnetic data in individual nanoparticles. Finally, the heat-treated colloidal FePt nanoparticles are found to be highly oxidized and contaminated by carbon because of the thermally induced decomposition of the organic shell. Recent alternative routes for the synthesis of L10 FePt nanoparticles include their formation in cluster beams and from wet-chemical procedures at elevated temperatures. However, even in these cases, the particles still need to be encapsulated with an organic-ligand shell, either after deposition from a cluster beam or during synthesis, to guarantee their ordered organization. Typical interparticle spacings are thus the same as described before, resulting in dipolar coupling and, additionally, the particle–ligand interactions can deteriorate the magnetic properties. Our new approach for generating ultrahigh-density arrays of L10 FePt nanoparticles overcomes all these drawbacks. It is based on the flexibility of macromolecular chemistry to design diblock copolymers with adjustable block lengths, which form reverse micelles when dissolved in an apolar solvent like toluene. After loading their cores with a suitable metal salt, such C O M M U N IC A TI O N

Ultrasonic spray coating is currently proven to be a reliable, flexible and cost efficient fabrication method for printed electronics [1-2]. Ultrasonic nozzles are by design especially well-suited to deposit nano-suspension dispersions. Due to the ultrasonic vibration of the nozzle, droplets having a median diameter of 20 μm are created in a homogeneous droplet cloud and directed towards the substrate. When one prepares an ink having the right wetting properties, thin and homogeneous layers, fully covering the surface, can be achieved. Together with conjugated polymer nanoparticles (NPs), emerging as a new class of nanomaterials, [3] it opens possibilities towards eco-friendly roll-to-roll processing of state-of-the-art organic bulk heterojunction solar cells. A ultrasonic spray coater was used to print the conjugated polymer NP layers under different conditions. A first optimization of the spray coater settings (flow rate, spray speed and temperature) and the ink formulation (water and co-solvent mixture and NP content) was performed for polystyrene particles dissolved in a water-ethanol mixture. As a next step, the low bandgap donor polymer poly[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophene-diyl] (PCDTBT) [4] and the fullerene acceptor phenyl-C71-butyric acid methyl ester (PCBM[70]) were combined in a water-based blend NP dispersion which was prepared using the mini-emulsion technique. [5,6] Optical Microscopy, profilometry and Scanning Electron Microscopy (SEM) are performed to study the roughness, surface structure, thickness and coverage of the spray coated layers. Finally the printed NP layers are integrated in organic bulk heterojunction solar cells and compared to spin coated reference devices.