High-Throughput Silica Nanoparticle Detection for Quality Control of Complex Early Life Nutrition Food Matrices.

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.

Self-assembling peptide matrix for treatment of dentin hypersensitivity: A randomized controlled clinical trial.

BACKGROUND: Patient-reported dentin hypersensitivity [DHS] pain is a common finding linked with periodontal disease. This pilot clinical study investigates a novel therapeutic regimen using self-assembling peptide matrix [SAPM] gel (test) compared with use of an 8% arginine and calcium carbonate [ACC] toothpaste (control) for treatment of DHS. METHODS: A total of 50 patients with history of supportive periodontal therapy were enrolled in this prospective, randomized monocentric clinical study, of which 45 (test: n = 22; control: n = 23) fulfilled all the study visits. Test group patients performed ex-office application of SAPM gel over 1 week, while control group patients performed ex-office application of ACC toothpaste over 90 days. DHS was assessed in office by Visual Analog Scale [VAS], and patient's perception of pain relief was evaluated by questionnaire. In support of the clinical data, scanning electron microscopy images were recorded to investigate tubule occlusion of both control and test product. RESULTS: Both SAPM and ACC significantly reduced DHS in patients throughout the study, with the patient questionnaire indicating higher patient satisfaction at the earlier time points for the test group. CONCLUSIONS: Both SAPM gel and ACC toothpaste were successful in providing relief from DHS and showed similar outcomes on VAS and verbal response scale (VRS) throughout the study period of 90 days. The new therapeutic regimen using SAPM resulted in higher patient satisfaction at day 7, as indicated by the patient questionnaire and the higher number of pain-free patients at day 7 and day 90. This is a pilot study describing a novel therapy for DHS.

Mineralization of Early Stage Carious Lesions In Vitro-A Quantitative Approach.

Micro computed tomography has been combined with dedicated data analysis for the in vitro quantification of sub-surface enamel lesion mineralization. Two artificial white spot lesions, generated on a human molar crown in vitro, were examined. One lesion was treated with a self-assembling peptide intended to trigger nucleation of hydroxyapatite crystals. We non-destructively determined the local X-ray attenuation within the specimens before and after treatment. The three-dimensional data was rigidly registered. Three interpolation methods, i.e., nearest neighbor, tri-linear, and tri-cubic interpolation were evaluated. The mineralization of the affected regions was quantified via joint histogram analysis, i.e., a voxel-by-voxel comparison of the tomography data before and after mineralization. After ten days incubation, the mean mineralization coefficient reached 35.5% for the peptide-treated specimen compared to 11.5% for the control. This pilot study does not give any evidence for the efficacy of peptide treatment nor allows estimating the necessary number of specimens to achieve significance, but shows a sound methodological approach on the basis of the joint histogram analysis.

Silsesquioxane/polyamine nanoparticle-templated formation of star- or raspberry-like silica nanoparticles.

Silica is an important mineral in biology and technology, and many protocols have been developed for the synthesis of complex silica architectures. The current report shows that silsesquioxane nanoparticles carrying polymer arms on their surface are efficient templates for the fabrication of silica particles with a star- or raspberry-like morphology. The shape of the resulting particles depends on the chemistry of the polymer arms. With poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) arms, spherical particles with a less electron dense core form. With poly{[2-(methacryloyloxy)ethyl] trimethylammonium iodide} (PMETAI), star- or raspberry-like particles form. Electron microscopy, electron tomography, and small-angle X-ray scattering show that the resulting silica particles have a complex structure, where a silsequioxane nanoparticle carrying the polymer arms is in the center. Next is a region that is polymer-rich. The outermost region of the particle is a silica layer, where the outer parts of the polymer arms are embedded. Time-resolved zeta-potential and pH measurements, dynamic light scattering, and electron microscopy reveal that silica formation proceeds differently if PDMAEMA is exchanged for PMETAI.

Evidence for haploinsufficiency of the human HNF1alpha gene revealed by functional characterization of MODY3-associated mutations.

Hepatocyte nuclear factor (HNF)1alpha is a homeo-domain-containing transcription factor participating in the regulation of gene expression in liver, kidney, gut and pancreas of vertebrates. In humans mutations in the HNF1 gene are responsible for one form of maturity onset diabetes of the young (MODY3). To define the molecular mechanism underlying MODY3 we investigated the functional properties of seven MODY3-associated mutations representing the spectrum of different kinds of mutations affecting all functional domains of the protein. The mutations introduced into an expression vector encoding human HNF1alpha include in-frame deletion (AN127), nonsense (Q7X, R171X), frameshift (P291fsinsC) and missense (R229Q, P447L, T6201) mutations. Gel retardation and reporter gene assays showed that the functional properties of these mutants differ dramatically, but none of these mutants act in a dominant negative manner. Moreover, the mRNA stability of the mutants AN127, R171X, P291fsinsC and T547E548fsdelTG is impaired compared to the wild-type sequence in transfected cells. This decreased RNA stability is independent of the presence of an intron in the expression vector and thus differs from mechanisms known to be involved in nonsense-mediated decay (NMD). Our results suggest that haploinsufficiency of HNF1alpha is responsible for the pathogenesis of MODY3.