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Biomaterials Sep 2023Biochemical and mechanical interactions between cells and the surrounding extracellular matrix influence cell behavior and fate. Mimicking these features in vitro has...
Biochemical and mechanical interactions between cells and the surrounding extracellular matrix influence cell behavior and fate. Mimicking these features in vitro has prompted the design and development of biomaterials, with continuing efforts to improve tailorable systems that also incorporate dynamic chemical functionalities. The majority of these chemistries have been incorporated into synthetic biomaterials, here we focus on modifications of silk protein with dynamic features achieved via enzymatic, "click", and photo-chemistries. The one-pot synthesis of vinyl sulfone modified silk (SilkVS) can be tuned to manipulate the degree of functionalization. The resultant modified protein-based material undergoes three different gelation mechanisms, enzymatic, "click", and light-induced, to generate hydrogels for in vitro cell culture. Further, the versatility of this chemical functionality is exploited to mimic cell-ECM interactions via the incorporation of bioactive peptides and proteins or by altering the mechanical properties of the material to guide cell behavior. SilkVS is well-suited for use in in vitro culture, providing a natural protein with both tunable biochemistry and mechanics.
Topics: Silk; Hydrogels; Biocompatible Materials; Cell Communication
PubMed: 37348323
DOI: 10.1016/j.biomaterials.2023.122201 -
Spectroscopy and Photochemistry of OAlNO and Implications for New Metal Chemistry in the Atmosphere.The Journal of Physical Chemistry. A Sep 2023A new aluminum-bearing species, OAlNO, which has the potential to impact the chemistry of the Earth's upper atmosphere, is characterized via high-level, , spectroscopic...
A new aluminum-bearing species, OAlNO, which has the potential to impact the chemistry of the Earth's upper atmosphere, is characterized via high-level, , spectroscopic methods. Meteor-ablated aluminum atoms are quickly oxidized to aluminum oxide (AlO) in the mesosphere and lower thermosphere (MLT), where a steady-state layer of AlO then builds up. Concurrent formation of nitric oxide (NO) in the same region of the atmosphere will lead to the bimolecular formation of the OAlNO molecule. Molecular orbital analysis provides fundamental insights into the chemical bonding and energetic arrangement of the triplet (1 A″) ground state and singlet (1 A') excited-state species of OAlNO. Additionally, unpaired electrons on the terminal oxygen atom of triplet (1 A″) OAlNO cause it to be reactive to atmospheric species, potentially impacting climate science and high-altitude chemistry. The triplet (1 A″) ground-state species exhibits a large permanent dipole moment useful for rotational spectroscopic detection; however, similar rotational constants to the singlet (1 A') excited-state species will hamper differentiation in a spectrum. Strong infrared intensities will assist in detection and discrimination of the different spin states and isomers. Repulsive electronic excited states of OAlNO will lead to photolysis of the Al-N bond and formation of various electronic states of AlO + NO through nonadiabatic pathways. Reaction through the OAlNO intermediate represents a means for the production of electronically excited AlO, leading to new chemistry in the atmosphere. Excitation to higher-lying electronic states will lead to fluorescence with a minor Stokes shift, useful for laboratory investigation. Such physical properties of this molecule will allow for new, unexplored chemical pathways in the MLT to be considered.
PubMed: 37647609
DOI: 10.1021/acs.jpca.3c04437 -
Frontiers in Chemistry 2023Sulfonylaniline motif plays an important role in pharmaceutical sciences. Developed methods towards this structure are typically lack of good modifiability and...
Sulfonylaniline motif plays an important role in pharmaceutical sciences. Developed methods towards this structure are typically lack of good modifiability and stability. In this study, visible-light-mediated sulfonylation of aniline using sulfonyl fluoride as a modifiable and stable sulfonylation reagent is described. A variety of substituted sulfonylanilines were synthesized under mild reaction conditions with moderate to good efficiency. The example of late-stage sulfonylation highlighted the advantage of using sulfonyl fluoride as a sulfonylation reagent. In addition, the crucial influence of counterions on the photocatalyst observed in this system would inspire further research on the photochemistry of sulfonyl fluoride.
PubMed: 37693172
DOI: 10.3389/fchem.2023.1267223 -
Angewandte Chemie (International Ed. in... Nov 2023Polymerization-induced self-assembly (PISA) is a powerful technique for preparing block copolymer nanostructures. Recently, efforts have been focused on applying...
Polymerization-induced self-assembly (PISA) is a powerful technique for preparing block copolymer nanostructures. Recently, efforts have been focused on applying photochemistry to promote PISA due to the mild reaction conditions, low cost, and spatiotemporal control that light confers. Despite these advantages, chain-end degradation and long reaction times can mar the efficacy of this process. Herein, we demonstrate the use of ultrafast photoiniferter PISA to produce polymeric nanostructures. By exploiting the rapid photolysis of xanthates, near-quantitative monomer conversion can be achieved within five minutes to prepare micelles, worms, and vesicles at various core-chain lengths, concentrations, or molar compositions.
PubMed: 37793989
DOI: 10.1002/anie.202309951 -
Advanced Materials (Deerfield Beach,... Feb 2024Strong coupling of molecules to vacuum fields is widely reported to lead to modified chemical properties such as reaction rates. However, some recent attempts to...
Strong coupling of molecules to vacuum fields is widely reported to lead to modified chemical properties such as reaction rates. However, some recent attempts to reproduce infrared strong coupling results have not been successful, suggesting that factors other than strong coupling may sometimes be involved. In the first vacuum-modified chemistry experiment, changes to a molecular photoisomerization process in the ultraviolet-visible spectral range are attributed to strong coupling of the molecules to visible light. Here, this process is re-examined, finding significant variations in photoisomerization rates consistent with the original work. However, there is no evidence that these changes need to be attributed to strong coupling. Instead, it is suggested that the photoisomerization rates involved are most strongly influenced by the absorption of ultraviolet radiation in the cavity. These results indicate that care must be taken to rule out non-polaritonic effects before invoking strong coupling to explain any changes of properties arising in cavity-based experiments.
PubMed: 37997481
DOI: 10.1002/adma.202309393 -
Advanced Materials (Deerfield Beach,... Jan 20243D printing with light is enabled by the photochemistry underpinning it. Without fine control over the ability to photochemically gate covalent bond formation by the... (Review)
Review
3D printing with light is enabled by the photochemistry underpinning it. Without fine control over the ability to photochemically gate covalent bond formation by the light at a certain wavelength and intensity, advanced photoresists with functions spanning from on-demand degradability, adaptability, rapid printing speeds, and tailored functionality are impossible to design. Herein, recent advances in photoresist design for light-driven 3D printing applications are critically assessed, and an outlook of the outstanding challenges and opportunities is provided. This is achieved by classing the discussed photoresists in chemistries that function photoinitiator-free and those that require a photoinitiator to proceed. Such a taxonomy is based on the efficiency with which photons are able to generate covalent bonds, with each concept featuring distinct advantages and drawbacks.
PubMed: 37681744
DOI: 10.1002/adma.202306468 -
The Science of the Total Environment Oct 2023This study reports day-night and seasonal variations of aqueous brown carbon (BrC) and constituent humic-like substances (HULIS) (neutral and acidic HULIS: HULIS-n and...
Optical source apportionment of aqueous brown carbon (BrC) on a daytime and nighttime basis in the eastern Indo-Gangetic Plain (IGP) and insights from C and N isotopic signatures.
This study reports day-night and seasonal variations of aqueous brown carbon (BrC) and constituent humic-like substances (HULIS) (neutral and acidic HULIS: HULIS-n and HULIS-a) from the eastern Indo-Gangetic Plain (IGP) of India during 2019-2020. This is followed by the application of the receptor model positive matrix factorization (PMF) for optical source apportionment of BrC and the use of stable isotopic ratios (δC and δN) to understand atmospheric processing. Nighttime BrC absorption and mass absorption efficiencies (MAE) were enhanced by 40-150 % and 50-190 %, respectively, compared to the daytime across seasons, possibly as a combined effect from daytime photobleaching, dark-phase secondary formation, and increased nighttime emissions. MAE/MAE (i.e., E/E) ratios and Angstrom Exponents revealed that BrC and HULIS-n were relatively more aromatic and conjugated during the biomass burning-dominated periods while BrC and HULIS-a were comprised mostly of non-conjugated aliphatic structures from secondary processes during the photochemistry-dominated summer. The relative radiative forcing of BrC with respect to elemental carbon (EC) was 10-12 % in the post-monsoon and winter in the 300-400 nm range. Optical source apportionment using PMF revealed that BrC absorption at 300, 365 and 420 nm wavelengths in the eastern IGP is mostly from biomass burning (60-75 %), followed by combined marine and fossil fuel-derived sources (24-31 %), and secondary processes (up to 10 %). Source-specific MAEs at 365 nm were estimated to be the highest for the combined marine and fossil fuel source (1.34 m g) followed by biomass burning (0.78 m g) and secondary processing (0.13 m g). Finally, δC and δN isotopic analysis confirmed the importance of summertime photochemistry and wintertime NO-dominated chemistry in constraining BrC characteristics. Overall, the quantitative apportionment of BrC sources and processing reported here can be expected to lead to targeted source-specific measurements and a better understanding of BrC climate forcing in the future.
PubMed: 37343876
DOI: 10.1016/j.scitotenv.2023.164872 -
Environmental Science. Processes &... Dec 2023Oil spills represent a major source of negative environmental impacts in marine systems. Despite many decades of research on oil spill behavior, photochemistry was... (Review)
Review
Oil spills represent a major source of negative environmental impacts in marine systems. Despite many decades of research on oil spill behavior, photochemistry was neglected as a major factor in the fate of oil spilled in marine systems. Subsequent to the Deepwater Horizon oil spill, numerous studies using varied approaches have demonstrated the importance of photochemistry, including short-term impacts (hours to days) that were previously unrecognized. These studies have demonstrated the importance of photochemistry in the overall oil transformation after a spill and more specifically the impacts on emulsification, oxygenation, and microbial interactions. In addition to new perspectives, advances in analytical approaches have allowed an improved understanding of oil photochemistry after maritime spill. Although the literature on the Deepwater Horizon spill is extensive, this review focuses only on studies relevant to the advances in oil photochemistry understanding since the Deepwater Horizon spill.
Topics: Petroleum Pollution; Photochemistry; Gulf of Mexico; Water Pollutants, Chemical
PubMed: 37881013
DOI: 10.1039/d3em00248a -
Biosensors Aug 2023Most agricultural land, as a result of climate change, experiences severe stress that significantly reduces agricultural yields. Crop sensing by imaging techniques... (Review)
Review
Most agricultural land, as a result of climate change, experiences severe stress that significantly reduces agricultural yields. Crop sensing by imaging techniques allows early-stage detection of biotic or abiotic stress to avoid damage and significant yield losses. Among the top certified imaging techniques for plant stress detection is chlorophyll fluorescence imaging, which can evaluate spatiotemporal leaf changes, permitting the pre-symptomatic monitoring of plant physiological status long before any visible symptoms develop, allowing for high-throughput assessment. Here, we review different examples of how chlorophyll fluorescence imaging analysis can be used to evaluate biotic and abiotic stress. Chlorophyll is able to detect biotic stress as early as 15 min after feeding, or 30 min after application on tomato plants, or on the onset of water-deficit stress, and thus has potential for early stress detection. Chlorophyll fluorescence (ChlF) analysis is a rapid, non-invasive, easy to perform, low-cost, and highly sensitive method that can estimate photosynthetic performance and detect the influence of diverse stresses on plants. In terms of ChlF parameters, the fraction of open photosystem II (PSII) reaction centers (q) can be used for early stress detection, since it has been found in many recent studies to be the most accurate and appropriate indicator for ChlF-based screening of the impact of environmental stress on plants.
Topics: Humans; Chlorophyll A; Agriculture; Dehydration; Optical Imaging; Stress, Physiological
PubMed: 37622882
DOI: 10.3390/bios13080796 -
Chemical Science Jan 2024This review article highlights the diverse ways in which recent developments in the areas of photocatalysis and visible light photochemistry are impacting synthetic... (Review)
Review
This review article highlights the diverse ways in which recent developments in the areas of photocatalysis and visible light photochemistry are impacting synthetic carbohydrate chemistry. The major topics covered are photocatalytic glycosylations, generation of radicals at the anomeric position, transformations involving radical formation at non-anomeric positions, additions to glycals, processes initiated by photocatalytic hydrogen atom transfer from sugars, and functional group interconversions at OH and SH groups. Factors influencing stereo- and site-selectivity in these processes, along with mechanistic aspects, are discussed.
PubMed: 38274059
DOI: 10.1039/d3sc05400d