Surface-Enhanced Raman Scattering (SERS)-based cancer imaging is of significant interest for histopathological examination, molecular analysis, and intraoperative guidance of tumor tissues due to its sensitive and specific detection of multiple cancer-associated biomarkers and stable signal over time. However, synthesis of SERS nanotags targeting cancer biomarkers is limited by the complexity in achieving a balance between Raman sensitivity, binding specificity, and nanoparticle stability. Here, we established a two-step PEG-based surface modification for 60 nm spherical gold nanoparticles to enable the SERS imaging of various ovarian cancer cell models expressing the epidermal growth factor receptor (EGFR). In contrast to conventional surface modification of gold-based SERS nanotags, our approach enables the simultaneous optimization of Raman activity, colloidal stability, and targeting specificity directly on gold nanoparticles. PEG-conjugated ⍺EGFR antibodies were successfully immobilized on 75.4 ± 4.6% of nanoparticles, with proof of accessible, active surface binding sites. Surface coverage with carboxyl-terminated poly(ethylene glycol)-1,4 benzenedithiol conjugate provided simultaneous SERS signal and steric stabilization, overcoming limitations associated with insufficient surface coverage of one or more functional groups. Colloidal stability during the two-step surface modification was maintained by the addition of surfactant Tween 80. Finally, SERS imaging demonstrated the specificity of our SERS nanotags toward EGFR-positive ovarian cancer cells (OVCAR5 and OVCAR8). Evaluation of ΔEGFR-OVCAR8 cells further confirmed that nanoparticle binding is primarily driven by specific antigen-antibody recognition, independent of cell line-specific effects. Overall, this work provides a promising strategy for effective SERS-based imaging of cancer, with potential for future clinical applications.

The addition of nanomaterials to improve product properties has become a matter of course for many commodities: e.g., detergents, cosmetics, and food products. While this practice improves product characteristics, the increasing exposure and potential impact of nanomaterials (<100 nm) raise concerns regarding both the human body and the environment. Special attention should be taken for vulnerable individuals such as those who are ill, elder, or newborns. But detecting and quantifying nanoparticles in complex food matrices like early life nutrition (ELN) poses a significant challenge due to the presence of additional particles, emulsion-droplets, or micelles. There is a pressing demand for standardized protocols for nanoparticle quantification and the specification of "nanoparticle-free" formulations. To address this, silica nanoparticles (SiNPs), commonly used as anticaking agents (AA) in processed food, were employed as a model system to establish characterization methods with different levels of accuracy and sensitivity versus speed, sample handling, and automatization. Different acid treatments were applied for sample digestion, followed by size exclusion chromatography. Morphology, size, and number of NPs were measured by transmission electron microscopy, and the amount of Si was determined by microwave plasma atomic emission spectrometry. This successfully enabled distinguishing SiNP content in ELN food formulations with 2-4% AA from AA-free formulations and sorting SiNPs with diameters of 20, 50, and 80 nm. Moreover, the study revealed the significant influence of the ELN matrix on sample preparation, separation, and characterization steps, necessitating method adaptations compared to the reference (SiNP in water). In the future, we expect these methods to be implemented in standard quality control of formulation processes, which demand high-throughput analysis and automated evaluation.

Enzymes are essential biocatalysts and very attractive as therapeutics. However, their functionality is strictly related to their stability, which is significantly affected by the environmental changes occurring during their usage or long-term storage. Therefore, maintaining the activity of enzymes is essential when they are exposed to high temperature during usage or when they are stored for extended periods of time. Here, we stabilize and protect enzymes by coencapsulating them with trehalose into polymersomes. The anhydrobiotic disaccharide preserved up to about 81% of the enzyme's original activity when laccase/trehalose-loaded nanoreactors were kept desiccated for 2 months at room temperature and 75% of its activity when heated at 50 °C for 3 weeks. Moreover, the applicability of laccase/trehalose-loaded nanoreactors as catalysts for bleaching of the textile dyes orange G, toluidine blue O, and indigo was proven. Our results demonstrate the advantages of coencapsulating trehalose within polymersomes to stabilize enzymes in dehydrated state for extended periods of time, preserving their activity even when heated to elevated temperature.

Surface-enhanced Raman spectroscopy (SERS)-based imaging has the potential to improve the intraoperative visualization of the exact tumor borders and infiltrating foci of glioblastoma (GBM), thus achieving a more complete surgical resection. However, successful and reliable outcomes can be invalidated by the inclination of gold nanoparticles (GNPs) to aggregate or bind nonspecifically to the cells preventing discrimination between the tumor and healthy cells. Stable and specifically targeting SERS tags are achieved through application of the appropriate GNP surface chemistry and by the correct balance of inert and active targeting functionalities. This requires an in-depth characterization of the effective immobilized functionalities on the GNP surface. GNPs with varying ratios of Raman reporter, poly(ethylene glycol) (PEG), and antibodies against epidermal growth factor receptor, which is overexpressed by GBM cells, were studied. The influence of each ratio on the GNP performance in terms of the maximal colloidal stability, sensitivity, and lowest nonspecific binding was characterized in detail both chemically and biologically. SERS tags coated with 50% Raman reporter surface coverage and conjugated to 3% antibody surface coverage showed the ideal chemistry functionalization. This allowed us to avoid GNP aggregation and to reduce nonspecific binding, while receiving enough Raman sensitivity for a fast and distinct discrimination between GBM tumor and nontumoral cell lines in vitro. Excess antibody did not improve the binding affinity of GNPs to tumor cells, but it reduced the conjugation efficiency by 35%. These findings open a stable and nonquenching alternative for GBM visualization compared to fluorescence-guided surgery, the current state-of-the-art technique for GBM imaging.

In the Swiss Universities of Applied Sciences, several research institutes are involved in Materials Science, with different approaches and applications fields. A few examples of recent projects from different groups of the University of Applied Sciences and Arts Western Switzerland (HESSO), the Zurich University of Applied Sciences (ZHAW) and the University of Applied Sciences and Arts Northwestern Switzerland (FHNW) are given.

Self-assembling peptide hydrogels can be modified regarding their biodegradability, their chemical and mechanical properties and their nanofibrillar structure. Thus, self-assembling peptide hydrogels might be suitable scaffolds for regenerative therapies and tissue engineering. Owing to the use of various peptide concentrations and buffer compositions, the self-assembling peptide hydrogels might be influenced regarding their mechanical characteristics. Therefore, the mechanical properties and stability of a set of self-assembling peptide hydrogels, consisting of 11 amino acids, made from four beta sheet self-assembling peptides in various peptide concentrations and buffer compositions were studied. The formed self-assembling peptide hydrogels exhibited stiffnesses ranging from 0.6 to 205 kPa. The hydrogel stiffness was mostly affected by peptide sequence followed by peptide concentration and buffer composition. All self-assembling peptide hydrogels examined provided a nanofibrillar network formation. A maximum self-assembling peptide hydrogel dissolution of 20% was observed for different buffer solutions after 7 days. The stability regarding enzymatic and bacterial digestion showed less degradation in comparison to the self-assembling peptide hydrogel dissolution rate in buffer. The tested set of self-assembling peptide hydrogels were able to form stable scaffolds and provided a broad spectrum of tissue-specific stiffnesses that are suitable for a regenerative therapy.

Background The regeneration of tissue defects at the interface between soft and hard tissue, eg, in the periodontium, poses a challenge due to the divergent tissue requirements. A class of biomaterials that may support the regeneration at the soft-to-hard tissue interface are self-assembling peptides (SAPs), as their physicochemical and mechanical properties can be rationally designed to meet tissue requirements. Materials and methods In this work, we investigated the effect of two single-component and two complementary β-sheet forming SAP systems on their hydrogel properties such as nanofibrillar architecture, surface charge, and protein adsorption as well as their influence on cell adhesion, morphology, growth, and differentiation. Results We showed that these four 11-amino acid SAP (P11-SAP) hydrogels possessed physico-chemical characteristics dependent on their amino acid composition that allowed variabilities in nanofibrillar network architecture, surface charge, and protein adsorption (eg, the single-component systems demonstrated an ~30% higher porosity and an almost 2-fold higher protein adsorption compared with the complementary systems). Cytocompatibility studies revealed similar results for cells cultured on the four P11-SAP hydrogels compared with cells on standard cell culture surfaces. The single-component P11-SAP systems showed a 1.7-fold increase in cell adhesion and cellular growth compared with the complementary P11-SAP systems. Moreover, significantly enhanced osteogenic differentiation of human calvarial osteoblasts was detected for the single-component P11-SAP system hydrogels compared with standard cell cultures. Conclusion Thus, single-component system P11-SAP hydrogels can be assessed as suitable scaffolds for periodontal regeneration therapy, as they provide adjustable, extracellular matrix-mimetic nanofibrillar architecture and favorable cellular interaction with periodontal cells.

Simultaneous detection of multiple biomarkers, such as extracellular signaling molecules, is a critical aspect in disease profiling and diagnostics. Precise positioning of antibodies on surfaces, especially at the micro- and nanoscale, is important for the improvement of assays, biosensors, and diagnostics on the molecular level, and therefore, the pursuit of device miniaturization for parallel, fast, low-volume assays is a continuing challenge. Here, we describe a multiplexed cytokine immunoassay utilizing electron beam lithography and a trehalose glycopolymer as a resist for the direct writing of antibodies on silicon substrates, allowing for micro- and nanoscale precision of protein immobilization. Specifically, anti-interleukin 6 (IL-6) and antitumor necrosis factor alpha (TNFα) antibodies were directly patterned. Retention of the specific binding properties of the patterned antibodies was shown by the capture of secreted cytokines from stimulated RAW 264.7 macrophages. A sandwich immunoassay was employed using gold nanoparticles and enhancement with silver for the detection and visualization of bound cytokines to the patterns by localized surface plasmon resonance detected with dark-field microscopy. Multiplexing with both IL-6 and TNFα on a single chip was also successfully demonstrated with high specificity and in relevant cell culture conditions and at different times after cell stimulation. The direct fabrication of capture antibody patterns for cytokine detection described here could be useful for biosensing applications.

Laccases (Lac) are oxidizing enzymes with a broad range of applications, for example, in soil remediation, as bleaching agent in the textile industry, and for cosmetics. Protecting the enzyme against degradation and inhibition is of great importance for many of these applications. Polymer vesicles (polymersomes) from poly(N-vinylpyrrolidone)-block-poly(dimethylsiloxane)-block-poly(N-vinylpyrrolidone) (PNVP-b-PDMS-b-PNVP) triblock copolymers were prepared and investigated as intrinsically semipermeable nanoreactors for Lac. The block copolymers allow oxygen to enter and reactive oxygen species (ROS) to leave the polymersomes. EPR spectroscopy proved that Lac can generate ROS. They could diffuse out of the polymersome and oxidize an aromatic substrate outside the vesicles. Michaelis-Menten constants Km between 60 and 143 μM and turn over numbers kcat of 0.11 to 0.18 s(-1) were determined for Lac in the nanoreactors. The molecular weight and the PDMS-to-PNVP ratio of the block copolymers influenced these apparent Michaelis-Menten parameters. Encapsulation of Lac in the polymersomes significantly protected the enzyme against enzymatic degradation and against small inhibitors: proteinase K caused 90% less degradation and the inhibitor sodium azide did not affect the enzyme's activity. Therefore, these polymer nanoreactors are an effective means to stabilize laccase.

Stimuli responsive surfaces that show reversible fluorescence switching behavior in response to temperature changes were fabricated. Oligo(ethylene glycol) methacrylate thermoresponsive polymers with amine end-groups were prepared by atom transfer radical polymerization (ATRP). The polymers were patterned on silicon surfaces by electron beam (e-beam) lithography, followed by conjugation of self-quenching fluorophores. Fluorophore conjugated hydrogel thin films were bright when the gels were swollen; upon temperature-induced collapse of the gels, self-quenching of the fluorophores led to significant attenuation of fluorescence. Importantly, the fluorescence was regained when the temperature was cooled. The fluorescence switching behavior of the hydrogels for up to ten cycles was investigated and the swelling-collapse was verified by atomic force microscopy. Morphing surfaces that change shape several times upon increase in temperature were obtained by patterning multiple stimuli responsive polymers.

Understanding and controlling cell adhesion on engineered scaffolds is important in biomaterials and tissue engineering. In this report we used an electron-beam (e-beam) lithography technique to fabricate patterns of a cell adhesive integrin ligand combined with a growth factor. Specifically, micron-sized poly(ethylene glycol) (PEG) hydrogels with aminooxy- and styrene sulfonate-functional groups were fabricated. Cell adhesion moieties were introduced using a ketone-functionalized arginine-glycine-aspartic acid (RGD) peptide to modify the O-hydroxylamines by oxime bond formation. Basic fibroblast growth factor (bFGF) was immobilized by electrostatic interaction with the sulfonate groups. Human umbilical vein endothelial cells (HUVECs) formed focal adhesion complexes on RGD- and RGD and bFGF-immobilized patterns as shown by immunostaining of vinculin and actin. In the presence of both bFGF and RGD, cell areas were larger. The data demonstrate confinement of cellular focal adhesions to chemically and physically well-controlled microenvironments created by a combination of e-beam lithography and "click" chemistry techniques. The results also suggest positive implications for addition of growth factors into adhesive patterns for cell-material interactions.

The development of new high performance, ultra-thin organic coatings requires a strategy that has to consider a large number of surface treatment variables such as binding moieties, substrate, and adsorption conditions (e.g. temperature, solvent, concentration, pH, salt). The optimization of the latter is often the bottleneck of the entire development process and restricts the number of parameters that can be tested with acceptable effort. Here we present a screening platform for the efficient, parallel testing of various surface modification protocols, based on an array of 70 wells for individual adsorption experiments with a volume of 20 μL each (SuMo device). The device performance was validated using the copolymer poly(l-lysine)- grafted-poly(ethylene glycol) (PLL-g-PEG) that adsorbs on negatively charged surfaces, rendering them non-fouling in contact with proteins such as fibrinogen. The latter functionality was tested by a second adsorption step of FITC-labelled fibrinogen; polymer and protein thickness values, measured by spectroscopic ellipsometry were used as a measure for the quality of the polymer adlayer. The results obtained are in excellent agreement with traditional coating methods using single chips for each parameter set. A further improvement in the efficiency of the surface modification experiments resulted from the use of a fluorescence read out of the fibrinogen adsorption. Measurements with a microarray scanner proved to be very fast providing uniform fluorescence images with low bleaching rate and high detection sensitivity. The results of the fluorescence readout correlated with the ellipsometry data with a lower limit of detection of ca. 2% of a saturated layer for both techniques. The readout data of the SuMo device were further compared with the quantitative results from in situ optical waveguide lightmode spectroscopy (OWLS) and successfully validated by testing the dependence of fibrinogen coverage as a function of fibrinogen solution concentration. Finally, to demonstrate its application feasibility, the array device was applied to study the polymeric surface layer stability under a range of harsh conditions (14 > pH > 1, ionic strength up to 5.3 M NaCl).

Nonfouling coatings, based on surface-tethered. hydrophilic polymer chains, have widespread application in areas such as biosensing, medical devices. and biotechnology. Self-organization of polymers is a particularly attractive approach given its simplicity and cost effectiveness in the application. Here we present a new class of polymers based on the Polycationic poly(L-lysine)-graft-poly(ethylene glycol) copolymer (PLL-g-PEG) with a fraction of the amine-terminated lysine side chains covalently conjugated to 3,4-dihydroxyphenylacetic acid (DHPAA). This copolymer is shown to adsorb and self-organize as a confluent monolayer on negatively charged titanium oxide surfaces, driven by long-range electrostatic attraction, while the catechol groups of DHPAA spontaneously engage in strong, coordinative binding to the substrate surface, similar to the biomimetic dihydroxyphenylalanine (DOPA) found in mussel adhesive proteins. The adsorption kinetics and resulting polymer coverage are demonstrated to critically depend on (a) a rational design of the copolymer architecture with a compromise between sufficient positive charges in the PLL backbone and a minimal grafting density of DHPAA groups and (b) optimum choice of ionic strength and temperature of the assembly solution. PLL-graft-(DHPAA; PEG) adlayers exhibit excellent resistance to nonspecific protein (Fibrinogen) adsorption. To test the chemical stability of the polymeric layer, coated substrates were exposed to high ionic salt solutions and proved to remain nonfouling thanks to Stable catechol-substrate anchorage, in stark contrast to the control PLL-g-PEG copolymer that desorbed under these conditions its a consequence of screening of the (purely) electrostatic surface forces. Furthermore, polymer-coated substrates resisted attachment of the cyanobacterium Lyngbya sp. over a time frame of at least 100 days.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The chiral ligands, 4,4'-bis{(1S,2R,4S)-(-)-bornyloxy)-2,2'-bipyridine, (1S,2R,4S)-1, and 4,4'-bis{(1R,2S,4R)-(+)-bornyloxy)-2,2'-bipyridine, (1R,2S,4R)-1, have been prepared and characterized by spectroscopic techniques and, for (1S,2R,4S)-1, by single crystal X-ray diffraction. Despite the use of enantiomerically pure ligands, the formation of the complexes [Fe((1S,2R,4S)-1)(3)](2+), [Ru((1S,2R,4S)-1)(3)](2+), [Ru((1S,2R,4S)-1)(bpy)(2)](2+) and [Ru((1R,2S,4R)-1)(bpy)(2)](2+) proceeds without preference for either the Delta or Lambda-diastereoisomers. (C) 2007 Elsevier Ltd. All rights reserved.

We report on a fabrication method of achieving local chemical modification of a surface at the sub-50-nm scale by a process sequence of nanoimprint lithography, gas phase surface modification and lift-off. This was combined with a new stamp fabrication via extreme ultraviolet interference lithography to produce extremely small patterns of high density and large area. In this method, we have demonstrated chemical patterns of a fluorinated silane on an unprecedented feature size of as small as 25-nm half pitch. However, chemical contrast of high quality needed for biological and sensing applications was still difficult to achieve due to the contamination on the background surface areas, which is associated with the lift-off process. This will be discussed with results obtained by subsequently immobilizing a fluorescence labeled protein on the chemical patterns using different lift-off conditions and process sequences.