Effective diagnosis of disease and itsp rogression can be aided by 19 Fm agnetic resonance imaging(MRI) techniques. Specifically,t he inherent sensitivity of the spin-lattice relaxationt ime (T 1)o f 19 Fn uclei to oxygen partial pressure makes 19 FMRI an attractive non-invasive approach to quantify tissue oxygenation in as patiotemporal manner. However,t here are only few materials with the adequate sensitivity to be used as oxygen-sensitive 19 FMRI agentsa t clinically relevant field strengths. Motivated by the limitations in current technologies, we reporth ighly fluorinated monomerst hat provide ap latform approach to realize water-soluble, partially fluorinated copolymers as 19 FMRI agents with the required sensitivityt oq uantify solution oxygenation at clinically relevant magnetic field strengths. The synthesis of as ystematic library of partially fluorinated co-polymers enabled ac omprehensive evaluationo fc opolymer structure-property relationships relevant to 19 FMRI. The highest-performing materialc ompositiond emonstrated a signal-to-noise ratio that corresponded to an apparent 19 F density of 220 mm,w hich surpasses the threshold of 126 mm 19 Fr equired for visualization on at hree Tesla clinical MRI. Furthermore, the T 1 of these high performing materials demonstrated al inear relationship with solution oxygenation, with oxygen sensitivity reaching 240 10 À5 mmHg À1 s À1. The relationships between material composition and 19 FMRI performance identified herein suggest general structureproperty criteria for the furtheri mprovement of modular, water-soluble 19 FMRI agents for quantifying oxygenation in environments relevant to medical imaging.

The impact of extraction methodology and polarity of extraction solvents on the assay of phenolic compounds was investigated using parsley (Petroselinum crispum) flakes as a model substrate. This systematic study was undertaken to address substantial variations in the extraction procedures, solvents and conditions as described in the recent literature. Five different extraction procedures [shaking, vortex mixing, sonication, stirring and pressurized liquid extraction (PLE)] and three different solvents (methanol, ethanol and acetone), with five different solvent to water ratios per solvent, were used for extraction. Extracts were analyzed for phenolic content by high-performance liquid chromatography and Folin-Ciocalteu assays. The yields of phenolic compounds extracted with a pressurized liquid extractor were comparable to or better than those of four classical extraction procedures. Optimum extraction efficiency with PLE was obtained when extractions were performed with four extraction cycles using ethanol-water (50:50, v/v). The amount of apiin (4,5,7-trihydroxyflavone 7-apiosylglucoside) and malonylapiin (apigenin malonylapiosylglucoside) isolated from parsley varied with the composition of extraction solvent. Apiin extractability was found to be a maximum when the solvent (ethanol, methanol or acetone) to water ratio was 30:70 (v/v), whereas higher amounts of malonylapiin were isolated with a reverse solvent to water ratio (70:30, v/v). Malonylapiin was not detected when parsley samples were extracted with organic solvent to water ratios of 10:90 (v/v) and 30:70 (v/v).

Naturally occurring and recombinant protein-based materials are frequently employed for the study of fundamental biological processes and are often leveraged for applications in areas as diverse as electronics, optics, bioengineering, medicine, and even fashion. Within this context, unique structural proteins known as reflectins have recently attracted substantial attention due to their key roles in the fascinating color-changing capabilities of cephalopods and their technological potential as biophotonic and bioelectronic materials. However, progress toward understanding reflectins has been hindered by their atypical aromatic and charged residue-enriched sequences, extreme sensitivities to subtle changes in environmental conditions, and well-known propensities for aggregation. Herein, we elucidate the structure of a reflectin variant at the molecular level, demonstrate a straightforward mechanical agitation-based methodology for controlling this variant’s hierarchical assembly, and establish a direct correlation between the protein’s structural characteristics and intrinsic optical properties. Altogether, our findings address multiple challenges associated with the development of reflectins as materials, furnish molecular-level insight into the mechanistic underpinnings of cephalopod skin cells’ color-changing functionalities, and may inform new research directions across biochemistry, cellular biology, bioengineering, and optics.

Collagen type I fiber-based scaffolds for anterior cruciate ligament (ACL) replacement were evaluated for their mechanical properties and their ability to promote cellular proliferation. Prior to scaffold formation, two crosslinking methods were investigated on individual reconstituted collagen type I fibers, ultraviolet radiation, and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). Crosslinking with EDC for 4 hr yielded mechanical properties similar to the human ACL; therefore, scaffold crosslinking was done with EDC for 4 hr. A braid-twist scaffold design was used, and scaffolds were left uncrosslinked, crosslinked after the addition of gelatin, or crosslinked without gelatin. The ultimate tensile strength, Young's modulus, and viscoelastic properties of the scaffolds were then evaluated. In order to assess cellular response on the scaffolds, primary rat ligament fibroblast cells were seeded upon the scaffolds. Cell activity was evaluated at days 7, 14, and 21 using a Cell Titer 96(®) AQueous One Solution Cell Proliferation Assay (MTS Assay). The mechanical testing results showed that among the three scaffold groups, the crosslinked scaffolds without gelatin displayed an ultimate tensile strength, Young's modulus, and viscoelastic properties that were closest to the human ACL. Improvements are still desired to enhance the mechanical compliance and ductility of these scaffolds. Cell activity was observed on all cell-seeded scaffolds by day 7, but by day 21 only the crosslinked scaffolds without gelatin displayed increased cellular activity compared with the negative controls. Although improvement is still needed, the results suggest that these scaffolds have the potential to contribute toward an ACL replacement strategy.

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