SAXS Research Articles

Tearing properties, crystallization behavior, microstructure, and morphology of LLDPE with different short branched chain distributions

Abstract The length and distribution of comonomers with short-chain branching (SCB) have a significant influence on the crystallization behavior and crystal structure of polymers, as well as the mechanical properties of the material. This study investigates the crystallization behavior and properties of linear low-density polyethylene (LLDPE) samples with similar density, molecular weight, and branching degree but varying SCB distributions. The results show that LLDPE with butene as the comonomer has a stronger ability to suppress crystallization compared to LLDPE with hexene as the comonomer due to its more uniform SCB distribution. Additionally, among LLDPEs with comonomers of octene, hexene, and butene, the LLDPE with the most uniform SCB distribution exhibits the weakest crystallization ability. Small-angle X-ray scattering (SAXS) and scanning electron microscopy (SEM) results indicate that LLDPE with more uniform distribution of SCB has smaller long-period and more regular lamellar structure. Therefore, LLDPE with more uniform SCB distribution exhibits weaker inhibition ability towards crystallization, leading to less agglomerated phases and weaker phase separation, resulting in higher tear strength.

Asymmetric fluctuation of overlapping dinucleosome studied by cryo-electron microscopy and small-angle X-ray scattering

Abstract Nucleosome remodelers modify the local structure of chromatin to release the region from nucleosome-mediated transcriptional suppression. Overlapping dinucleosomes (OLDNs) are nucleoprotein complexes formed around transcription start sites as a result of remodeling, and they consist of two nucleosome moieties: a histone octamer wrapped by DNA (octasome) and a histone hexamer wrapped by DNA (hexasome). While OLDN formation alters chromatin accessibility to proteins, the structural mechanism behind this process is poorly understood. Thus, this study investigated the characteristics of structural fluctuations in OLDNs. First, multiple structures of the OLDN were visualized through cryo-electron microscopy (cryo-EM), providing an overview of the tilting motion of the hexasome relative to the octasome at the near-atomistic resolution. Second, small-angle X-ray scattering (SAXS) revealed the presence of OLDN conformations with a larger radius of gyration than cryo-EM structures. A more complete description of OLDN fluctuation was proposed by SAXS-based ensemble modeling, which included possible transient structures. The ensemble model supported the tilting motion of the OLDN outlined by the cryo-EM models, further suggesting the presence of more diverse conformations. The amplitude of the relative tilting motion of the hexasome was larger, and the nanoscale fluctuation in distance between the octasome and hexasome was also proposed. The cryo-EM models were found to be mapped in the energetically stable region of the conformational distribution of the ensemble. Exhaustive complex modeling using all conformations that appeared in the structural ensemble suggested that conformational and motional asymmetries of the OLDN result in asymmetries in the accessibility of OLDN-binding proteins.

Solvent Choice during Flow Assembly of Photocross-Linked Single-Chain Nanoparticles and Micelles Affects Cellular Uptake.

Polymeric micelles have widely been used as drug delivery carriers, and recently, single-chain nanoparticles (SCNPs) emerged as potential, smaller-sized, alternatives. In this work, we are comparing both NPs side by side and evaluate their ability to be internalized by breast cancer cells (MCF-7) and macrophages (RAW 264.7). To be able to generate these NPs on demand, the polymers were assembled by flow, followed by the stabilization of the structures by photocross-linking using blue light. The central aim of this work is to evaluate how the type of solvent affects self-assembly and ultimately the structure of the final NP. Therefore, a library of copolymers with different sequences, including block copolymers (AB, ABA, BAB), and statistical copolymers (rAB and rAC) was synthesized using PET-RAFT with A denoting poly(ethylene glycol) methyl ether acrylate (PEGMEA), B as 2-hydroxyethyl acrylate (HEA), and C as 4-hydroxybutyl acrylate (HBA). The polymers were conjugated with a quinoline derivative to enable the formation of cross-linked structures by photocross-linking during flow assembly. Using water as the dispersant for photocross-linking led to the preassembly of these amphiphilic polymers into compact SCNPs and cross-linked micelles, resulting in a quick photoreaction. In contrast, acetonitrile led to fully dissolved polymers but a low rate of the photoreaction. These intramolecularly cross-linked polymers were then placed in water to result in more dynamic micelles and looser SCNPs. Small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), and size exclusion chromatography (SEC) coupled with a viscosity detector show that cross-linking in acetonitrile results in better-defined NPs with a shell rich in PEGMEA. Cross-linking in acetonitrile led to NPs with significantly higher cellular uptake. Interestingly, passive transport was identified as the main pathway for the delivery of our NPs on MCF-7 cells, confirmed by the uptake of NPs on cells treated with inhibitors and by red blood cells. This work underscored the importance of the polymer precursor's structure and the choice of solvent during intramolecular cross-linking in determining the drug delivery efficiency and biological behavior of SCNPs.

Molecular dynamics and small-angle x-ray scattering: a comparison computational and experimental approaches to studying the structure of biological complexes

The results of studying DNA-protein complexes using two independent structural methods – molecular dynamics (MD) and small-angle X-ray scattering (SAXS) – are compared. MD is a computational method that allows visualization of macromolecule behavior in real environmental conditions based on the laws of physics but suffers from numerous simplifications. SAXS is an X-ray method that allows the reconstruction of the three-dimensional structure of an object in solution based on the one-dimensional profile of small-angle scattering, which presents the problem of ambiguity in solving inverse problems. The use of structural characteristics of complexes obtained by the SAXS method for validating 3D structural models obtained in MD experiments has significantly reduced the ambivalence of theoretical predictions and demonstrated the effectiveness of combining MD and SAXS methods for solving structural biology problems.

Near-Infinite-Chain Polymers with Ge=Ge Double Bonds.

Despite considerable interest in heteroatom-containing conjugated polymers, there are only few examples with heavier p-block elements in the conjugation path. The recently reported heavier acyclic diene metathesis (HADMET) allowed for the synthesis of a polymer containing Ge=Ge double bonds - albeit insoluble and with limited degree of polymerization. By incorporation of long alkyl chains, we now obtained soluble representatives, which exhibit degrees of polymerization near infinity according to diffusion-ordered NMR spectroscopy (DOSY) and dynamic light scattering (DLS). Analyses of the UV/Vis absorption and the NMR spectroscopic data confirm the presence of σ,π-conjugation across the silylene-phenylene linkers between the Ge=Ge double bonds. Favorable intermolecular dispersion interactions lead to ladder-like cylindrical supramolecular assemblies as confirmed by X-ray diffraction (XRD), small angle X-ray scattering (SAXS) and DLS. AFM and TEM images of deposited thin films reveal lamellar ordering of extended polymer bundles.

Near‐Infinite‐Chain Polymers with Ge=Ge Double Bonds

Despite considerable interest in heteroatom‐containing conjugated polymers, there are only few examples with heavier p‐block elements in the conjugation path. The recently reported heavier acyclic diene metathesis (HADMET) allowed for the synthesis of a polymer containing Ge=Ge double bonds – albeit insoluble and with limited degree of polymerization. By incorporation of long alkyl chains, we now obtained soluble representatives, which exhibit degrees of polymerization near infinity according to diffusion‐ordered NMR spectroscopy (DOSY) and dynamic light scattering (DLS). Analyses of the UV/Vis absorption and the NMR spectroscopic data confirm the presence of σ,π‐conjugation across the silylene‐phenylene linkers between the Ge=Ge double bonds. Favorable intermolecular dispersion interactions lead to ladder‐like cylindrical supramolecular assemblies as confirmed by X‐ray diffraction (XRD), small angle X‐ray scattering (SAXS) and DLS. AFM and TEM images of deposited thin films reveal lamellar ordering of extended polymer bundles.

Structural-functional analysis of modified kudzu starch as a novel instant powder: Role of modified technology

Adopting effective methods to modify starch structure for enhanced functional properties has become a pivotal pursuit within the realm of food science. This study investigated the physicochemical and structural properties of ball milling-modified kudzu starch (BS), extrusion puffing-modified kudzu starch (ES), alcohol-alkali-modified kudzu starch (ANS), urea-alkali-modified kudzu starch (UNS), pullulanase-modified kudzu starch (PS), and extrusion puffing-pullulanase-modified kudzu starch (EPS). The d (0.5) value increasing from 10.54 μm (NS) to 83.99 μm (ANS). The Small-angle X-ray scattering (SAXS) characteristic curve of other modified kudzu starch disappeared except for the UNS. The solubility of EPS was the highest, ranging from 73 % to 80 %, significantly higher than that of NS (0 %–1 %). The agglomeration rates of ES and EPS were 0.3 % and 0.6 %, respectively, at a stirring time of 30 s. indicating favorable hydration properties. Flavonoids content in ES increased to 0.1825 mg/g. Moreover, the resistant starch content of modified kudzu starch was increased, ranging from 58.50 %–86.87 %. This study is expected to provide a scientific foundation for selecting optimal modification methods for the production of instant kudzu powder.

Manipulation of Supramolecular Chirality in Bicontinuous Networks of Bent-Shaped Polycatenar Dimers.

Bicontinuous cubic liquid crystalline (LC) phases are of particular interest due their possible applications in electronic devices and special supramolecular chirality. Herein, we report the design and synthesis of first examples of achiral bent-shaped polycatenar dimers, capable of displaying mirror symmetry breaking in their cubic and isotropic liquid phases. The molecules have a taper-shaped 3,4,5-trialkoxybenzoate segment connected to rod-like building unit terminated with one terminal flexible chain. The two segments were connected using an aliphatic spacer with seven methylene units to induce bending of the whole structure. Investigated by the small-angle X-ray scattering (SAXS), a double network achiral cubic phase Cub/Ia3 d, which is a meso-structure, and a chiral triple network cubic phase Cub/I23[*] are formed. The molecules self-assemble into molecular helices and progress along the networks. Interestingly, different linking groups such as ester or azo linkages and core fluorination lead to distinct local helicity, resulting in an alkyl chain volume dependent phase transition sequence Ia3d(L)-I23*-Ia3d(S). The re-entry of Iad phase and loss of supramolecular chirality is attributed to the delicate influence of steric effect at the mono-substitute end and interhelix interaction. Besides, aromatic core fluorination was proved to be a successful tool stabilizing the cubic phases in these dimers.

Pyrrolizwilline, a unique bacterial alkaloid assembled by a nonribosomal peptide synthetase and non‐enzymatic dimerization

Pyrrolizidine alkaloids (PAs) are a structurally diverse group of heterocyclic specialized metabolites characterized by a core structure comprising a hexahydro‐1H‐pyrrolizine. PAs are synthesized through two main pathways. In plants, assembly occurs via a homospermidine synthase, and in bacteria, through combined action of a nonribosomal peptide synthetase and a Baeyer‐Villiger monooxygenase. While the toxic properties of plant‐derived PAs and their prevalence in animal and human foods have been extensively studied, the biological roles and biosynthesis of more complex bacterial PAs are not well understood. Here, we report the identification and characterization of a bacterial biosynthetic gene cluster from Xenorhabdus hominickii, xhpA‐G, which is responsible for producing the PA pseudo‐dimer pyrrolizwilline. Analysis of X. hominickii promoter exchange mutants together with heterologous expression of xhpA‐G in E. coli, revealed a set of pathway intermediates, two of which were chemically synthesized, as well as multiple derivatives. This information was leveraged to propose a detailed biosynthetic pathway to pyrrolizwilline. Furthermore, we have characterized the hydrolase XhpG, the key enzyme in the conversion of the pathway intermediate pyrrolizixenamide to pyrrolizwilline, using X‐ray crystallography and small‐angle X‐ray scattering (SAXS).

Pyrrolizwilline, a unique bacterial alkaloid assembled by a nonribosomal peptide synthetase and non-enzymatic dimerization.

Pyrrolizidine alkaloids (PAs) are a structurally diverse group of heterocyclic specialized metabolites characterized by a core structure comprising a hexahydro-1H-pyrrolizine. PAs are synthesized through two main pathways. In plants, assembly occurs via a homospermidine synthase, and in bacteria, through combined action of a nonribosomal peptide synthetase and a Baeyer-Villiger monooxygenase. While the toxic properties of plant-derived PAs and their prevalence in animal and human foods have been extensively studied, the biological roles and biosynthesis of more complex bacterial PAs are not well understood. Here, we report the identification and characterization of a bacterial biosynthetic gene cluster fromXenorhabdus hominickii,xhpA-G, which is responsible for producing the PA pseudo-dimer pyrrolizwilline. Analysis ofX. hominickiipromoter exchange mutants together with heterologous expression ofxhpA-GinE. coli, revealed a set of pathway intermediates, two of which were chemically synthesized, as well as multiple derivatives. This information was leveraged to propose a detailed biosynthetic pathway to pyrrolizwilline. Furthermore, we have characterized the hydrolase XhpG, the key enzyme in the conversion of the pathway intermediate pyrrolizixenamide to pyrrolizwilline, using X-ray crystallography and small-angle X-ray scattering (SAXS).

Linker-Mediated Inactivation of the SAM-II Domain in the Tandem SAM-II/SAM-V Riboswitch.

Tandem SAM-II/SAM-V riboswitch belongs to a class of riboswitches found in the marine bacterium 'Candidatus Pelagibacter ubique'. Previous studies have demonstrated that these riboswitches have the potential for digital modulation of gene expression at both the transcriptional and translational levels. In this study, we investigate the conformational changes in the tandem SAM-II/SAM-V riboswitch binding to S-adenosylmethionine (SAM) using selective 2'-hydroxyl acylation analyzed by the primer extension (SHAPE) assay, small-angle X-ray scattering (SAXS), and oligos depressing probing. Our findings reveal that the linker between SAM-II/SAM-V aptamers blocks the SAM response of the SAM-II domain. This result proposes a new mechanism for gene expression regulation, where the ligand-binding functions of tandem riboswitches can be selectively masked or released through a linker.

Exploration of the Photoluminescence Behavior and Emission Mechanism of Thioester Polyacrylamide Tablets During the Gradual Increase of Molecular Weight.

To enhance the photoluminescence (PL) of unconventional luminescent compounds, particularly their persistent room temperature phosphorescence (p-RTP) performance, compressing the powder into tablets has been demonstrated as a viable approach. Nevertheless, the alterations in the emission capability of PL in compacted tablets have not been comprehensively investigated. In this study, four polyacrylamide (PAM) with controllable molecular weight (MW) are fabricated from powder to tablets, and their PL emission properties are thoroughly examined and compared with corresponding powders to elucidate the emission mechanism. As MW increases, both PL and p-RTP emissions of the tablets gradually intensify, exhibiting significant enhancement compared to the corresponding powder while retaining the characteristic blue shift. Through small angle X-ray scattering (SAXS), construction of molecular models for tablets, detailed analysis of molecular interactions, and theoretical calculations are conducted to reasonably explain these emission phenomena using clustering-triggered emission (CTE) and average packing density promoted emission (PDE) mechanisms. These findings not only advance the understanding of nonconventional luminogens' emission mechanisms but also offer new insights for preparing nonconventional luminescent polymers with controllable p-RTP emission performance.

Self-Assembly and Wound Healing Activity of Biomimetic Cycloalkane-Based Lipopeptides.

The self-assembly of lipopeptide (peptide amphiphile) molecules bearing single linear lipid chains has been widely studied, as has their diverse range of bioactivities. Here, we introduce lipopeptides bearing one or two cycloalkane chains (cycloheptadecyl or cyclododecyl) conjugated to the collagen-stimulating pentapeptide KTTKS used in Matrixyl formulations. The self-assembly of all four molecules is probed using fluorescence probe measurements to detect the critical aggregation concentration (CAC), and cryogenic-TEM and small-angle X-ray scattering (SAXS) to image the nanostructure. The peptide conformation is studied using circular dichroism (CD) and FTIR spectroscopies. All the cycloalkane lipopeptides show excellent compatibility with dermal fibroblasts. The compounds bearing one or two cyclododecyl chains (denoted as DKT and DDKT, respectively) show wound healing in diabetic rats, the improvement being markedly enhanced for DDKT. Interestingly, the revival of hair follicles and blood vessels in the dermis were observed, which are the critical markers of effective wound repair. Analysis of H&E-stained tissue images (from a rat model) shows that the rat groups treated with DDKT and DKT displayed a significantly increased amount of regenerated hair follicles, indicating a faster healing process for DDKT compared to the control group. Collagen deposition was also enhanced, especially for DDKT, and by day 20, the DDKT-treated groups had developed a dense collagen network accompanied by a regenerated epidermis. At the same time, the number of blood vessels in DDKT-treated diabetic wounds was significantly higher than in control groups and neovascularization was substantially enhanced, as assayed using α-SMA (a marker for vascular smooth muscle cells) and CD31 (a marker specific to vascular endothelial cells). These results suggest that the lead lipopeptide DDKT exhibits a remarkable pro-vascularization capability and shows great promise for future application as a wound-healing biomaterial.

Supraparticles from Cubic Iron Oxide Nanoparticles: Synthesis, Polymer Encapsulation, Functionalization, and Magnetic Properties.

Supraparticles (SPs) consisting of superparamagnetic iron oxide nanoparticles (SPIONs) are of great interest for biomedical applications and magnetic separation. To enable their functionalization with biomolecules and to improve their stability in aqueous dispersion, polymer shells are grown on the SPs' surface. Robust polymer encapsulation and functionalization is achieved via atom transfer radical polymerization (ATRP), improving the reaction control compared to free radical polymerizations. This study presents the emulsion-based assembly of differently sized cubic SPIONs (12-30 nm) into SPs with diameters ranging from ∼200 to ∼400 nm using dodecyltrimethylammonium bromide (DTAB) as the surfactant. The successful formation of well-defined spherical SPs depends upon the method used for mixing the SPION dispersion with the surfactant solution and requires the precise adjustment of the surfactant concentration. After purification, the SPs are encapsulated by growing surface-grafted polystyrene shells via activators generated by electron transfer (AGET) ATRP. The polymer shell can be decorated with functional groups (azide and carboxylate) using monomer blends for the polymerization reaction. When the amount of the monomer is varied, the shell thickness as well as the interparticle distances between the encapsulated SPIONs can be tuned with nanometer-scale precision. Small-angle X-ray scattering (SAXS) reveals that cubic SPIONs form less ordered assemblies within the SPs than spherical SPIONs. As shown by vibrating sample magnetometer measurements, the encapsulated SPs feature the same superparamagnetic behavior as their SPION building blocks. The saturation magnetization ranges between 10 and 30 emu/g and depends upon the nanocubes' size and phase composition.

High-temperature furnace for in situ GISAXS studies

Abstract A high-temperature furnace was constructed to perform in situ Grazing-Incidence Small-Angle X-ray Scattering (GISAXS) experiments at high temperatures for isothermal studies. The furnace consists of two interconnected chambers: (i) a main chamber housing the heating elements, where the sample is inserted during GISAXS measurements, and (ii) a pre-chamber where the sample is maintained near room temperature until the temperature in the main chamber reaches the pre-selected value. The two-chamber design allows a rapid increase of the sample temperature and avoids the sample overheating, conditions desirable for studies of the formation and growth of nanoparticles under isothermal annealing. In a practical application, the furnace was used to investigate the kinetics of the formation of NiSi2 silicide nanocrystals endotaxially grown in Si(001) wafers. This experiment allowed us to gain insights into the growth process and evaluate the performance of the furnace for in situ GISAXS studies. The high-temperature furnace provides a robust tool for studying the effect of annealing temperature on the kinetics of the growth of nanoparticles in thermally activated processes with special advantages in studies in which isothermal conditions are required.

Lamellar liquid crystals in commercial polyether‐modified polydimetilsiloxanes for coating applications: Structure, rheology and cross‐linking

AbstractWe have constructed the phase diagrams in water of two commercial additives for coatings consisting of polyether‐modified polydimethylsiloxanes. These aqueous systems form a liquid crystal mesophase (LC) at copolymer concentrations higher than 60 wt%. At low copolymer concentrations, this LC coexists with a diluted aqueous phase. Small angle x‐ray scattering (SAXS) measurements and polarized optical microscope observations indicate that the structure of the mesophase is lamellar, with an interlayer spacing that increases linearly with the concentration of water in the system. The lamellar liquid crystals display temperature‐dependent viscoelastic behavior, with the copolymer with longer spacing showing a much lower elastic modulus. Since one of the copolymer has terminal acryl groups, its lamellar phase can be crosslinked to produce gelled liquid crystals. Other cross‐linked self‐assembled structures, such as bicontinuous microemulsions, are envisaged.

Rheology and aging of amine functionalized polyolefins

The time dependent rheo-mechanical properties of a class of associating polymers (amine-functionalized polyolefins) are investigated using rheology, differential scanning calorimetry (DSC), infrared microscopy, and small-angle x-ray scattering (SAXS) measurement. The modulus of the sample increases with time and temperature as determined by shear rheology. With higher temperature and longer equilibration time, there is a gradual decrease in the power-law scaling of storage and loss moduli in the terminal flow region and the emergence of an additional low-frequency plateau in the storage modulus. The aging behavior at different temperatures is found to be correlated with the horizontal shift factors obtained from the time-temperature superposition. With increasing aging time, there is an increase in the glass transition temperatures (DSC), and a continuous red shift in the associated amine stretching peak (Fourier-transform infrared). SAXS also shows the emergence of a dominant microstructure after aging of the sample for a long time. Based on the characterization results, an underlying microscopic origin of the aging process is proposed.

Preparation and evaluation of novel oral tacrolimus nanocochleates for organ transplantation to reduce individual differences and improve drug safety

After organ transplantation, patients require treatment with immunosuppressive drugs to prevent immune rejection and transplantation failure. Tacrolimus (FK506) is a widely used immunosuppressant known for its potent immunosuppressive effect and narrow therapeutic range. Monitoring of FK506 blood concentrations is essential to avoid nephrotoxicity. In this study, a novel FK506 nanomedicine (FK506 cochleates) was developed using a microfluidic method to reduce variability among individuals and improve drug safety. The particle size of FK506 cochleates was (183.3 ± 1.4) nm, the zeta potential was −(39.28 ± 2.12) mV, and the encapsulation efficiency was more than 85 %. Particle size of FK506 cochleates could be maintained for up to 12 weeks in freeze-dried powder form. Small-angle X-ray scattering (SAXS) experiment confirmed the formation of cochleates by adding calcium solution. In vitro release studies demonstrated a sustained-release profile of FK506 from the cochleates carrier. Furthermore, the cochleates carrier could protect FK506 from the influence of stomach acid and slowly release the drug in the intestine. After oral administration, FK506 cochleates exhibited sustained-release properties in rats, accumulating in the spleen and lymph nodes − key anatomical sites for FK506’s pharmacological action. Importantly, FK506 cochleates significantly prolonged the survival time in the rabbit heart transplantation model while maintaining good safety profiles. In conclusion, the FK506 cochleates showed promising potential for enhancing drug safety in therapeutic organ transplantation.

Comparative Study of Polycaprolactone and Polylactic Acid as Matrices for Atorvastatin Release - Biomaterial Suppliers for Additive Manufacturing in Drug Delivery Systems using nanocomposites

The use of the polymer/drug combination in additive manufacturing involves filament production through hot melt extrusion (HME). Atorvastatin (ATV) has diverse effects, including bone anabolism and cardiovascular improvements. This study compares the addition of ATV to polycaprolactone (PCL) and polylactic acid (PLA). Filaments of PCL/ATV and PLA/ATV were produced through HME and characterized by Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), Raman, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and Small-Angle X-ray Scattering (SAXS). ATV release was assessed using UV-Vis. The EDS analysis confirmed the presence of ATV in the filament, despite it not being possible, based on surface morphology, to distinguish between polymer and drug, which indicates good dispersion of ATV in the polymeric matrix. FTIR, RAMAN, XRD, and SAXS analyses reveal ATV's distinct interactions with PLA and PCL. FTIR highlights ATV's stronger interaction with PLA, while Raman indicates changes in PLA, they are less pronounced than in PCL. The XRD shows PLA's amorphous nature compared to PCL semi crystallinity nature. XRD suggests potential ATV amorphization in PLA_ATVf (filaments), while PCL_ATVf shows a decrease in crystallinity compared to PCL. HME's effect on ATV is essential. Despite ATV's crystallinity in PCL-ATVf by XRD, its release resembles PLA_ATVf. At the eighth hour, ATV release from PCL_ATVf was 12% higher than from PLA_ATVf. The data fitted the Korsmeyer-Peppas model.

Uncertainty quantification on small angle x-ray scattering measurement using Bayesian deep learning

Small angle x-ray scattering (SAXS) is a widely recognized solution for measuring complex nanostructures. With the increasing demand for accurately assessing structural characteristics and optimizing manufacturing processes, uncertainty quantification in SAXS inverse problems has become a critical issue. However, traditional methods face challenges such as slow computation speed and inaccurate estimation of multidimensional parameters. To overcome these issues, we propose an uncertainty quantification approach suitable for SAXS measurement that approximates the posterior using Bayesian deep learning. The effectiveness and reliability of our method are illustrated by assessing structural parameters of synthetic 2D Si grating samples. The uncertainty quantification takes only about 2.3 s, thousands of times faster than the conventional Markov Chain Monte Carlo (MCMC) methods. Also, our method has superior repeatability for parameter measurement compared to the MCMC approaches. It provides the potential of efficient and reliable SAXS measurement in increasingly intricate semiconductor manufacturing.