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ACS Macro Letters Apr 2022Bottlebrush polymers are characterized by an expansive parameter space, including graft length and spacing along the backbone, and these features impact various...
Bottlebrush polymers are characterized by an expansive parameter space, including graft length and spacing along the backbone, and these features impact various structural and physical properties such as molecular diffusion and bulk viscosity. In this work, we report a synthetic strategy for making grafted block polymers with poly(propylene oxide) and poly(ethylene oxide) side chains, bottlebrush analogues of poloxamers. Combined anionic and sequential ring-opening metathesis polymerization yielded low dispersity polymers, at full conversion of the macromonomers, with control over graft length, graft end-groups, and overall molecular weight. A set of bottlebrush poloxamers (BBPs), with identical graft lengths and composition, was synthesized over a range of molecular weights. Dynamic light scattering and transmission electron microscopy were used to characterize micelle formation in aqueous buffer. The critical micelle concentration scales exponentially with overall molecular weight for both linear and bottlebrush poloxamers; however, the bottlebrush architecture shifts micelle formation to a much higher concentration at a comparable molecular weight. Consequently, BBPs can exist in solution as unimers at significantly higher molecular weights and concentrations than the linear analogues.
Topics: Micelles; Molecular Weight; Poloxamer; Polymerization; Polymers
PubMed: 35575325
DOI: 10.1021/acsmacrolett.2c00053 -
Scientific Reports Nov 2022Lignin is a natural and renewable aromatic polymer, but only about 2% of lignin is utilized with high added value. Polydispersity and heterogeneity are the key reasons...
Lignin is a natural and renewable aromatic polymer, but only about 2% of lignin is utilized with high added value. Polydispersity and heterogeneity are the key reasons for the difficulty in separation, fractionation, characterization, purification and utilization of lignin. However, the molecular weight of lignin is still described from the overall perspective of number-/weight-average molecular weight (Mn and Mw), which if far from enough to understand the heterogeneous and dispersed lignin. To provide a tool for understanding the molecular weight of lignin from a molecular perspective, an integral method for quantifying the molecular characteristics of lignin molecules at arbitrary molecular intervals on the molecular weight distribution curve of lignin was established. The molecular contents of wheat straw lignin as well as its soluble and insoluble fractions at different intervals were calculated. The ease of fractionation of small molecules with weights lower than 8000 g/mol into soluble fractions, and that of large molecules with weights higher than 10,000 g/mol into insoluble fractions were quantitatively analyzed. The established integral method will significantly help in the understanding the properties of lignin at the molecular-level, as well as the fractionation and utilization of lignin.
Topics: Lignin; Chemical Fractionation; Triticum; Molecular Weight
PubMed: 36352251
DOI: 10.1038/s41598-022-23884-5 -
Scientific Reports Oct 2023Drug release kinetics in two compositions of methacrylate hydrogels were monitored as a function of the hydrogel and drug molecular weight. Through modifying the...
Drug release kinetics in two compositions of methacrylate hydrogels were monitored as a function of the hydrogel and drug molecular weight. Through modifying the molecular weight of hydrogels, it was demonstrated how the release could be tuned, allowing for increased stability of hydrogels and enhanced release performance. Spectroscopy techniques such as FTIR and UV-Vis-NIR provided inferences into the chemical structure, target molecule concentration, and optical performance of the studied hydrogels. By studying the 30-day target molecule loading stability of the hydrogels, a relationship between the drug and hydrogel molecular weight, and the drug release kinetics could be determined.
Topics: Hydrogels; Polymers; Molecular Weight; Methacrylates; Kinetics
PubMed: 37794078
DOI: 10.1038/s41598-023-42923-3 -
Molecular weight degradation and rheological properties of schizophyllan under ultrasonic treatment.Ultrasonics Sonochemistry Mar 2015Molecular weight degradation effects of schizophyllan (SPG) under ultrasonic treatments were investigated in this study. The degradation product was treated by alcohol...
Molecular weight degradation effects of schizophyllan (SPG) under ultrasonic treatments were investigated in this study. The degradation product was treated by alcohol fractional precipitation technology, and the molecular weight and rheological properties of ultrasonic-treated SPG (USPG) fractions were evaluated. Average molecular weight of SPG decreased significantly after ultrasonic treatments, and degradation product had more narrow distribution of molecular weight. The molecular weight degradation kinetics of SPG is adequately described by a second-order reaction. USPG fractions with different molecular weight were obtained by fractional precipitation for final alcohol concentration fractions 0-40%, 40-60% and 60-80%, respectively. USPG fractions had near-Newtonian flow behaviors, and USPG₈₀% exhibited viscous responses over the entire accessible frequency range. Therefore, ultrasonic treatment is a viable modification technology for SPG and other polymer materials with high molecular weight.
Topics: Kinetics; Molecular Weight; Rheology; Sizofiran; Ultrasonics
PubMed: 25263766
DOI: 10.1016/j.ultsonch.2014.09.008 -
Atherosclerosis Oct 2019
Topics: Apoprotein(a); Hydroxymethylglutaryl-CoA Reductase Inhibitors; Lipoprotein(a); Molecular Weight; Phenotype
PubMed: 31443913
DOI: 10.1016/j.atherosclerosis.2019.07.021 -
Journal of the American Chemical Society Jun 2022Low molecular weight gels are formed by the self-assembly of small molecules into anisotropic structures that form a network capable of immobilizing the solvent. Such... (Review)
Review
Low molecular weight gels are formed by the self-assembly of small molecules into anisotropic structures that form a network capable of immobilizing the solvent. Such gels are common, with a huge number of different examples existing, and they have many applications. However, there are still significant gaps in our understanding of these systems and challenges that need to be addressed if we are to be able to fully design such systems. Here, a number of these challenges are discussed.
Topics: Gels; Molecular Weight; Solvents
PubMed: 35713375
DOI: 10.1021/jacs.2c02096 -
Molecules (Basel, Switzerland) Sep 2022Mass spectrometry (MS) has become the central technique that is extensively used for the analysis of molecular structures of unknown compounds in the gas phase. It... (Review)
Review
Mass spectrometry (MS) has become the central technique that is extensively used for the analysis of molecular structures of unknown compounds in the gas phase. It manipulates the molecules by converting them into ions using various ionization sources. With high-resolution MS, accurate molecular weights (MW) of the intact molecular ions can be measured so that they can be assigned a molecular formula with high confidence. Furthermore, the application of tandem MS has enabled detailed structural characterization by breaking the intact molecular ions and protonated or deprotonated molecules into key fragment ions. This approach is not only used for the structural elucidation of small molecules (MW < 2000 Da), but also crucial biopolymers such as proteins and polypeptides; therefore, MS has been extensively used in multiomics studies for revealing the structures and functions of important biomolecules and their interactions with each other. The high sensitivity of MS has enabled the analysis of low-level analytes in complex matrices. It is also a versatile technique that can be coupled with separation techniques, including chromatography and ion mobility, and many other analytical instruments such as NMR. In this review, we aim to focus on the technical advances of MS-based structural elucidation methods over the past five years, and provide an overview of their applications in complex mixture analysis. We hope this review can be of interest for a wide range of audiences who may not have extensive experience in MS-based techniques.
Topics: Complex Mixtures; Ions; Molecular Weight; Peptides; Tandem Mass Spectrometry
PubMed: 36235003
DOI: 10.3390/molecules27196466 -
Chemistry, An Asian Journal Apr 2021The analysis of low molecular weight (LMW) compounds is of great interest to detect small pharmaceutical drugs rapidly and sensitively, or to trace and understand... (Review)
Review
The analysis of low molecular weight (LMW) compounds is of great interest to detect small pharmaceutical drugs rapidly and sensitively, or to trace and understand metabolic pathways. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) plays a central role in the analysis of high molecular weight (bio)molecules. However, its application for LMW compounds is restricted by spectral interferences in the low m/z region, which are produced by conventional organic matrices. Several strategies regarding sample preparation have been investigated to overcome this problem. A different rationale is centred on developing new matrices which not only meet the fundamental requirements of good absorption and high ionization efficiency, but are also vacuum stable and "MALDI silent", i. e., do not give matrix-related signals in the LMW area. This review gives an overview on the rational design strategies used to develop matrix systems for the analysis of LMW compounds, focusing on (i) the modification of well-known matrices, (ii) the search for high molecular weight matrices, (iii) the development of binary, hybrid and nanomaterial-based matrices, (iv) the advance of reactive matrices and (v) the progress made regarding matrices for negative or dual polarity mode.
Topics: Molecular Structure; Molecular Weight; Organic Chemicals; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 33657276
DOI: 10.1002/asia.202100044 -
Angewandte Chemie (International Ed. in... Oct 2022Small-molecular-weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification....
Small-molecular-weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification. Here, we present molecular mechanisms by which these additives regulate stability and composition of both CaCO solutions and solid ACC. Potent antiscalants inhibit ACC precipitation by interacting with prenucleation clusters (PNCs); they specifically trigger and integrate into PNCs or feed PNC growth actively. Only PNC-interacting additives are traceable in ACC, considerably stabilizing it against crystallization. The selective incorporation of potent additives in PNCs is a reliable chemical label that provides conclusive chemical evidence that ACC is a molecular PNC-derived precipitate. Our results reveal additive-cluster interactions beyond established mechanistic conceptions. They reassess the role of small-MW molecules in crystallization and biomineralization while breaking grounds for new sustainable antiscalants.
Topics: Calcium Carbonate; Crystallization; Molecular Weight
PubMed: 35785466
DOI: 10.1002/anie.202208475 -
Trends in Biotechnology Sep 2022There is an increasing demand for rapid, affordable, in-field screening methods for low molecular weight (LMW) compound detection. Anti-idiotypes (Ab2s) are biologically... (Review)
Review
There is an increasing demand for rapid, affordable, in-field screening methods for low molecular weight (LMW) compound detection. Anti-idiotypes (Ab2s) are biologically derived surrogates that can replace LMW compounds and their protein conjugates in immunoassays. Substitution with anti-idiotypes can improve assay standardisation, reduce cost, and contribute to environmental safety. Their application has been limited by difficult generation processes and varied effects on assay performance. This review examines a recent resurgence in the use of Ab2s within LMW compound detection, driven by the application of phage display and nanobodies. The methods used for Ab2 production are critically discussed and their potential role in improving LMW compound immunoassays is highlighted. Finally, forward-looking ideas for the production of anti-idiotypes are provided, along with barriers to their generation.
Topics: Immunoassay; Immunoglobulin Idiotypes; Molecular Weight
PubMed: 35317925
DOI: 10.1016/j.tibtech.2022.02.008