Bound Water Molecules Research Articles

Chemical conversion of CO2 into cyclic carbonates by two Metal–Organic frameworks

Two metal–organic frameworks (MOFs), DDCu and DDMn have been synthesized from a tetracarboxylate ligand by solvothermal method. DDCu contained paddlewheel- [Cu2(COO)4] clusters with axial sites occupied by water molecules and comprised of two types of cages: smaller spherical cages of diameter 9.3 Å and larger ellipsoidal cages of dimensions of 12.4 × 17.7 Å2. While DDMn having bimetallic Mn2(COO)4 clusters with 1D rhombus channels of window size 10.16 × 8.97 Å2. Both the MOFs have open framework structure with solvent accessible void volume 66.5 % and 64.1 % based on the PLATON calculations. The MOFs have been characterized by a series of methods like Single crystal XRD, powder XRD, FT-IR, TGA and N2 adsorption study. Brunauer−Emmett−Teller (BET) surface area of the activated MOFs were 360 and 290 m2/g, respectively. The loosely bound water molecules could be removed to produce unsaturated metal coordination sites that rendered exciting heterogeneous catalytic properties at the metal center of DDCu and DDMn in the fixation of CO2 through the cycloaddition of CO2 with various epoxide. Under ambient conditions (25 °C and 1 atm. CO2 pressure), both the catalyst showed appreciable yields (96 and 91 %) and selectivity (>99 %) for cyclic carbonate formations. Both the catalysts showed very good recycling properties (at least five times).

Water Networks in Complexes between Proteins and FDA-Approved Drugs.

Water molecules at protein-ligand interfaces are often of significant pharmaceutical interest, owing in part to the entropy which can be released upon the displacement of an ordered water by a therapeutic compound. Protein structures may not, however, completely resolve all critical bound water molecules, or there may be no experimental data available. As such, predicting the location of water molecules in the absence of a crystal structure is important in the context of rational drug design. Grand canonical Monte Carlo (GCMC) is a computational technique that is gaining popularity for the simulation of buried water sites. In this work, we assess the ability of GCMC to accurately predict water binding locations, using a dataset that we have curated, containing 108 unique structures of complexes between proteins and Food and Drug Administration (FDA)-approved small-molecule drugs. We show that GCMC correctly predicts 81.4% of nonbulk crystallographic water sites to within 1.4 Å. However, our analysis demonstrates that the reported performance of water prediction methods is highly sensitive to the way in which the performance is measured. We also find that crystallographic water sites with more protein/ligand hydrogen bonds and stronger electron density are more reliably predicted by GCMC. An analysis of water networks revealed that more than half of the structures contain at least one ligand-contacting water network. In these cases, displacement of a water site by a ligand modification might yield unexpected results if the larger network is destabilized. Cooperative effects between waters should therefore be explicitly considered in structure-based drug design.

Flexible and biocompatible poly (vinyl alcohol)/multi-walled carbon nanotubes hydrogels with epsilon-near-zero properties

• Flexible PVA/MWCNTs hydrogels were fabricated by solution method, and cytotoxicity experiments proved that the process was environmentally friendly and hydrogels were biocompatible. • Epsilon-near-zero properties were realized at radio frequency from PVA/MWCNTs hydrogels, originated from the resonance of the induced electric dipole. • After the frequency achieving epsilon-near-zero, negative permittivity which was different from Drude model but related to interband transition, was observed. Epsilon-near-zero (ENZ) material has been a research hotspot in recent years due to unique physical properties such as inverse Doppler effect and negative refractive index, showing great potentials in the fields of flexible electronics, wearable devices, sensors, etc. The ENZ materials are mostly reported at visible, infrared and terahertz wavelengths, while the report about ENZ materials at radio frequency is rare. In this work, flexible and biocompatible poly (vinyl alcohol)/multi-walled carbon nanotubes (PVA/MWCNTs) hydrogels, which were successfully fabricated by an environmentally friendly method, were used as ENZ materials at radio frequency for the first time. Cytotoxicity experiments proved that the experimental process and products are green, environmentally friendly and biocompatible. The microstructure, crystalline structure, chemical composition and dielectric properties were investigated. Two different water states, which were free water molecules and bound water molecules, coexisted in these PVA/MWCNTs hydrogels and accounted for about 37.5 wt% and 15.9 wt% respectively by analyzing the thermogravimetric analysis curves. When the MWCNTs content reached 12 wt% and 15 wt%, the continuous conductive MWCNTs network was formed in the hydrogel, and ENZ phenomenon was observed at about 760 kHz and 580 kHz respectively, which was attributed to the interband transition. Considering the flexibility and non-toxicity of PVA/MWCNTs hydrogels, the ENZ properties of this structure at the radio frequency can be well used in wearable invisibility cloak, flexible electronics, skin sensors and other wearable devices.

Coumarin 337 in aqueous solution: interplay between excitation and hydration

Excitation of the C337, highly fluorescent dye in an aqueous solution was studied by the TD-DFT. Through the B3PW91/6-311++G(d, p)/IEFPCM theory level, we obtained the C337 vibronic absorption spectrum which exactly reproduces the experimental maximum. Significant differences are shown between the results of calculating the transition energies using the models of vertical and vibronic transitions. Upon excitation, the main shift of the electron density occurs from C10 to C4 neighboring atom. Thus, large-scale ICT not occur. The effect of excitation on the vibrational spectra of C337 was analyzed. A single C337 molecule and its five different hydration complexes with strongly bound water molecules have been analyzed. Various hydrate complexes of the dye have been studied, and the effect of hydration on its excitation vibrational properties has been elucidated. It was taken into account that a water molecule can attach to the nitrogen atom N1 ("A" type) and the C=O carbonyl ("B" type), and cyano C≡N ("C" type) groups of the dye.

Molecular mechanism of hydrophobic tail chain saturation in nonionic surfactants changing the wettability of anthracite

Coal dust is a significant issue when it comes to the safety of coal mine operations. To create efficient surfactants for coal dust, it is crucial to comprehend the molecular principles governing the interactions between surfactants, water, and coal. In this investigation, the macromolecular model of anthracite was constructed. Polysorbate 60 (T60) and Polysorbate 80 (T80) were selected. First, using contact angle measurements, Fourier transform infrared spectroscopy (FTIR) experiment, and Wetting heat measurements, we contrasted how T60 and T80 affected the wettability of coal surfaces. Second, the causes for the various abilities of T60 and T80 were described from a microscopic perspective using molecular dynamics simulation, by evaluating mean square displacement (MSD), mass density, hydrophobic tail chain sequence parameters, interaction energy. According to the findings, T80 has a superior wetting impact on anthracite because it increases the coal surface's polarity and enhances its capacity to bind water molecules; The unsaturated double bond in T80 limited the free expansion of its hydrophobic tail, but following adsorption to the surface of anthracite, it expanded, resulting in a denser and more concentrated layered structure.

MCR-Raman spectroscopy of sodium octanoate micelles in aqueous solutions

Development of nanotechnologies and the active use of self-organization processes of amphiphilic compounds in them require fast and accurate diagnostics of these processes. Active use of sodium octanoate in medicine, pharmaceuticals and nanotechnologies necessitates the elimination of existing contradictions in scientific studies of the surfactants self-organization in water and conducting diagnostics of NaС8 solutions at a higher quality level. In this study, self-organization of micelle-forming compounds in water was studied on the example of sodium octanoate by combining laser Raman spectroscopy and MCR-ALS analysis. As a result of the analysis of the OH- and CH-groups stretching bands structure using the MCR method, the spectral components were identified as the stretching bands of water molecules that are not in contact with surfactants, and molecules formed monomers, dimers and micelles surrounded by hydration shells during the surfactants self-organization. Comparative analysis of the dependences of the water stretching band characteristics and characteristics of the obtained components of the OH-groups stretching bands decomposition on the NaC8 concentration showed that the most bound water molecules are in the aqueous shell of dimers, and the weakliest bound are in the aqueous shell of micelles. It was found that the formation of dimers and micelles increases the fraction of hydrocarbon surfactant chains in the trans-conformation. It is shown that using Raman spectroscopy in combination with the MCR method, it is possible not only qualitatively, but also quantitatively to estimate the ratio of monomers, dimers and micelles in solution and fraction of surfactant ions present in micelles.

Identification of amino acid residues in a proton release pathway near the bacteriochlorophyll dimer in reaction centers from Rhodobacter sphaeroides.

Insight into control of proton transfer, a crucial attribute of cellular functions, can be gained from investigations of bacterial reaction centers. While the uptake of protons associated with the reduction of the quinone is well characterized, the release of protons associated with the oxidized bacteriochlorophyll dimer has been poorly understood. Optical spectroscopy and proton release/uptake measurements were used to examine the proton release characteristics of twelve mutant reaction centers, each containing a change in an amino acid residue near the bacteriochlorophyll dimer. The mutant reaction centers had optical spectra similar to wild-type and were capable of transferring electrons to the quinones after light excitation of the bacteriochlorophyll dimer. They exhibited a large range in the extent of proton release and in the slow recovery of the optical signal for the oxidized dimer upon continuous illumination. Key roles were indicated for six amino acid residues, Thr L130, Asp L155, Ser L244, Arg M164, Ser M190, and His M193. Analysis of the results points to a hydrogen-bond network that contains these residues, with several additional residues and bound water molecules, forming a proton transfer pathway. In addition to proton transfer, the properties of the pathway are proposed to be responsible for the very slow charge recombination kinetics observed after continuous illumination. The characteristics of this pathway are compared to proton transfer pathways near the secondary quinone as well as those found in photosystem II and cytochrome c oxidase.

Exploring the Dynamic Heterogeneity at the Interface of a Protein in Aqueous Ionic Liquid Solutions.

Room temperature molecular dynamics (MD) simulations of the globular protein α-lactalbumin in aqueous solutions containing BMIM (1-butyl-3-methylimidazolium) based ionic liquids (ILs) with a series of Hofmeister anions have been carried out. In particular, effects of anions of different shapes/sizes and hydrophobic/hydrophilic characters, namely, thiocyanate (SCN-), dicyanamide (DCA-), methyl sulfate (MS-), triflate (TFO-), and bis(trifluoromethane) sulfonimide (TF2N-) on the heterogeneous dynamic environment at the interface around the protein have been explored. The calculations revealed exchange of population between water and IL cation-anion components beyond the first layer of bound water molecules at the protein surface. Further, increasingly restricted diffusivity of the IL components and water around the protein has been found to be associated with a longer time scale for the onset of dynamic heterogeneity at the interface. Restricted diffusivity of water molecules at the interface in the presence of the ILs has been found to be correlated with the longer time scale of structural relaxations of protein-water hydrogen bonds at the interface. More importantly, the time scale associated with the reorientations of the anions has been found to be anticorrelated with their translational diffusivity, with the effect being more at the interface as compared to the bulk IL solutions. It is demonstrated that the nonuniform ability of the anions to form hydrogen bonds with water due to their differential shapes and hydrophilic characters is the origin of such anticorrelation.

Roles of the Flexible Primary Coordination Sphere of the Mn4CaOx Cluster: What Are the Immediate Decay Products of the S3 State?

The primary coordination sphere of the multinuclear cofactor (Mn4CaOx) in the oxygen-evolving complex (OEC) of photosystem II is absolutely conserved to maintain its structure and function. Recent time-resolved serial femtosecond crystallography identified large reorganization of the primary coordination sphere in the S2 to S3 transition, which elicits a cascade of events involving Mn oxidation and water molecule binding to a putative catalytic Mn site. We examined how the crystallographic fields, created by transient conformational states of the OEC at various time points, affect the thermodynamics of various isomers of the Mn cluster using DFT calculations, with an aim of comprehending the functional roles of the flexible primary coordination sphere in the S2 to S3 transition and in the recovery of the S2 state. The results show that the relative movements of surrounding residues change the size and shape of the cavity of the cluster and thereby affect the thermodynamics of various catalytic intermediates as well as the ability to capture a new water molecule at a coordinatively unsaturated site. The implication of these findings is that the protein dynamics may serve to gate the catalytic reaction efficiently by controlling the sequence of Mn oxidation/reduction and water binding/release. This interpretation is consistent with EPR experiments; g ∼ 5 and g ∼ 3 signals obtained after near-infrared (NIR) excitation of the S3 state at 4 K and a g ∼ 5 only signal produced after prolonged incubation of the S3 state at 77 K can be best explained as originating from water-bound S2 clusters (Stotal = 7/2) under a S3 ligand field, i.e., the immediate one-electron reduction products of the oxyl-oxo (Stotal = 6) and hydroxo-oxo (Stotal = 3) species in the S3 state.

Moisture-enabled hydrovoltaic power generation with milk protein nanofibrils

Biologic materials have been shown to be good candidates for moisture-enabled hydrovoltaic power generation, but only those from specific bacterial cells have been explored. Herein, we report a moist-electric generator (PN-MEG) based on protein nanofibrils from milk β-lactoglobulin. The as-developed device can generate an open-circuit voltage of up to 0.65 V and a short-current of 2.9 µA. This device can generate a maximum power density of 38.88 μW·cm−2, which is one order of magnitude larger than those of previously reported analogous devices. The superior performance of this device is attributed to the remarkable hydrophilicity, high ionization and surface-to-volume ratio of protein nanofibrils. Density functional theory (DFT) calculations revealed that carboxyl groups were the favorable active sites in protein nanofibrils for binding water molecules. This study provides a novel perspective for common protein nanofibrils and paves the way for developing high-performance hydrovoltaic devices from biological materials.

Learning from hair moisture sorption and hysteresis.

The process of moisture sorption and desorption by human hair was analysed for extracting hints on the hair structure. The isotherms of moisture sorption and desorption by hair were recorded for untreated and chemically treated (permed and bleached) hair. Data of swelling were also considered. By examining the swelling and moisture sorption of keratin fibres, it is possible to conclude that hysteresis is quite improbably caused by capillary condensation. The mobility of the protein chains and the strength of the bonds binding water molecules to the active sites inside the matrix are proposed as causes instead. The concept of "breaking symmetry", derived from moisture sorption- desorption data, and the method of evaluating this parameter, is proposed as a way of characterizing the chemical treatment of hair. The results show that bleaching produces a larger breaking of symmetry than perming, and this is suggested to be due to new hydrogen bonds, created as a result of the chemical treatment, replacing the original disulphide bonds, which are of different strength compared to the bonds of untreated hair. The quantitative sorption data matched well to the model of grains of matrix enveloped in layers of water molecules at increasing relative humidity, up to 100%. The analysis suggested that, aside from the glass transition event occurring at around 60%-70% relative humidity, there is another, less examined, transition occurring at around 30% relative humidity, assigned to the opening of the hair inner structure, and accommodation of more water molecules. Both transitions are reflected by corresponding changes in the fibre mechanical behaviour. The moisture sorption-desorption by hair was shown to not only allow a quantitative differentiation among various cosmetic treatments of the hair but to also provide valuable information on the structure of the fibre.

Binding and distribution of water molecules in DPPC bilayers doped with β-sitosteryl sulfate

We have comparatively studied the behavior of water molecules associated with the DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) bilayers in the presence and absence of β–sitosteryl sulfate (PSO4) with the help of differential scanning calorimetry (DSC) and SAXS (small-angle x-ray scattering) techniques. The DSC heating endotherms were analyzed to understand the intermolecular interactions between water molecules and the lipid headgroups. The strongly bound, weakly bound, and free water (SB-Water, WB-Water, and FW-Water, respectively) were thus identified in the bilayers and the impact of incorporating PSO4 was evaluated. The SAXS data provided the supporting evidence for the impact of PSO4 on the intake of water into the bilayer. Regardless of the presence or absence of PSO4, the SB-Water existed in the system as the non-freezable fraction. On the other hand, the WB-Water and FW-Water fractions, both of which are freezable, exhibited freezing and melting behaviors that differed from each other significantly. The enthalpies of fusion of the WB-Water, which differed from that of the FW-Water, also varied with the mole fractions of PSO4. PSO4 enhanced the fraction of WB -water in the bilayer while at the same time reducing the fractions of SB-Water and FW-Water. The optimum retainability and the ease of release of the available water makes this system efficient for maintaining skin homeostasis if used in cosmetic and pharmaceutical formulations.

Study of water vapor sorption by cellulose esters with different degrees of substitution

In this research, the sorption of water vapor (WV) by various cellulose esters with different degrees of substitution (SD) has been studied. It was found that if the sorption value is measured in moles of H2O per mole of repeating units of the esters, then sorption properties depend only on the degree of substitution and not on the type of substituent. The lowest sorption is observed for triesters due to the absence of hydroxyl groups, which have the greatest contribution to the sorption process. To describe sorption isotherms, a calculating equation A = Ao(1- K lnφ)-1 was derived, where Ao is the maximum sorption value at relative vapor pressure φ=1, and K is the coefficient. This equation allows adequately describing experimental S-shaped sorption isotherms of WV for various esters having different SD. It was shown that the most probable sorption mechanism is the binding of polar water molecules by polar groups of various esters.

Exploring the druggability of oxidized low-density lipoprotein (ox-LDL) receptor, LOX-1, a proatherogenic drug target involved in atherosclerosis

Lectin-like oxidized low-density lipoprotein (ox-LDL) receptor 1 (LOX-1) is a vital scavenger receptor involved in ox-LDL binding, internalization, and subsequent proatherogenic signaling leading to cellular dysfunction and atherosclerotic plaque formation. Existing data suggest that modulation of ox-LDL - LOX-1 interaction can prevent or slow down atherosclerosis. Therefore, we utilized computational methods such as multi-solvent simulation and characterized two top-ranked druggable sites. Using systematic molecular docking followed by atomistic molecular dynamics simulation, we have identified and shortlisted small molecules from the NCI library that target two key binding sites. We demonstrate, using surface plasmon resonance (SPR), that four of the shortlisted molecules bind one-on-one to the purified C-terminal domain (CTLD) of LOX-1 receptor with high affinity (KD), ranging from 4.9 nM to 20.1 μM. Further, we performed WaterMap analysis to understand the role of individual water molecules in small molecule binding and the LOX-1-ligand complex stability. Our data clearly show that LOX-1 is druggable with small molecules. Our study provides strategies to identify novel inhibitors to attenuate ox-LDL – LOX-1 interaction.

Crystal Growth, Structural and Thermal Studies of FeC4H4O6·2.5H2O

Single crystals of iron(II) tartrate hemi-pentahydrate, FeC4H4O6·2.5H2O, were grown by the gel method using silica gels. Differential scanning calorimetry, thermogravimetric-differential thermal analysis, and X-ray diffraction measurements were performed on the single crystals. The space group symmetry (orthorhombic P212121) and structural parameters were determined at room temperature. The crystal structure consisted of slightly distorted FeO6 octahedra, C4H4O6 and H2O molecules, C4H4O6–Fe–C4H4O6 chains jointed by Fe–O bonds, and O–H···O hydrogen-bonding frameworks between adjacent molecules. Weight losses due to thermal decomposition of the crystal were found to occur in the temperature range of 300–1060 K. We inferred that the weight losses were caused by the evaporation of bound water molecules and the evolution of H2CO, CO, and O2 gases from C4H4O6 molecules, and that the black residue after decomposition was composed of triiron tetraoxide (Fe3O4) and carbon.

Anion-assisted supramolecular assemblies of zinc(II) complexes with isonicotinamide

Five zinc(II) coordination compounds, [ZnCl2(isn)2] (1), [ZnBr2(isn)2] (2), [Zn(NO3)2(H2O)(isn)2] (3), [Zn(CH3COO)2(isn)]2 (4) and [Zn(isn)4(H2O)2](ClO4)2 (5) (isn = isonicotinamide), were prepared by the reactions of the isonicotinamide (pyridine-4-carboxamide, isn) and corresponding zinc(II) salts. Their crystal structures were determined by the single-crystal X-ray diffraction method. The coordination environment of zinc(II) is tetrahedral in the compounds containing small halide anions (chloride, bromide), 1 and 2. An expansion of the zinc(II) coordination environment to the octahedral is observed in the presence of the monodentate and bridging nitrate ions in 3. The coordination environments of both zinc(II) ions in dimeric acetate complex 4 is also enlarged in the comparison with 1 and 2, one zinc(II) ion being octahedrally coordinated and the other being pentacoordinated. The zinc(II) ion in 5 also reaches higher coordination environment (octahedral), which is enabled by binding of additional water molecules, since the perchlorate ion is uncoordinated. The supramolecular amide-amide homosynthon R22(8) is preserved in the presence of halide, nitrate and acetate ions (1–4), but it is completely disrupted in the crystal packing of 5 due to the presence of the bulky perchlorate anion. Spectroscopic analysis of compounds 1–5 was performed by IR spectroscopy in the solid state and by 13C NMR spectroscopy in the DMSO solutions. The NMR data support a complete decomposition of 3 in the DMSO solution, but 1, 2, 4 and 5 remain unchanged in the solution. Thermal properties of the coordination compounds were also investigated by TGA and DSC methods.

Specific protein-urea interactions

The mechanism of urea's action in protein denaturation remains largely unknown. To provide an experimental basis for molecular dynamics (MD) simulations on urea-protein interactions, we investigated the effect of urea on human intestinal fatty acid binding protein (hIFABP) by nuclear magnetic resonance (NMR). Hydrogen-deuterium exchange (HDX) rates at ≤ 2 M urea indicate that urea affects hIFABP in a residue-specific manner via direct urea-protein interactions and preferentially weakens hydrogen bonds between highly protected amides. Residue-specific effects of urea on NMR peak intensities and chemical shifts further support the presence of direct urea-protein interactions. Two-dimensional (2D) water-rotating frame Overhauser enhancement (ROE) data shows one protein-bound water molecule in contact with Val66 and Trp82, one putative bound water molecule in interaction with Thr76 and E-F loop, and that urea at low concentrations cannot displace these protein-bound water molecules. Our urea-nuclear Overhauser effect (NOE) experiments using 15N-urea further show no tightly protein-bound urea molecules. Our results thus suggest specific, but weak or transient, urea-protein interactions, supporting the direct interaction model of urea denaturation.

Water-Regulated Mechanisms for Degradation of Pesticides Paraoxon and Parathion by Phosphotriesterase: Insight from QM/MM and MD Simulations.

The enzymatic degradation of pesticides paraoxon (PON) and parathion (PIN) by phosphotriesterase (PTE) has been investigated by QM/MM calculations and MD simulations. In the PTE-PON complex, Znα and Znβ in the active site are five- and six-coordinated, respectively, while both zinc ions are six coordinated with the Znα -bound water molecule (WT1) for the PTE-PIN system. The hydrolytic reactions for PON and PIN are respectively driven by the nucleophilic attack of the bridging-OH- and the Znα -bound water molecule on the phosphorus center of substrate, and the two-step hydrolytic process is predicted to be the rate-limiting step with the energy spans of 13.8 and 14.4 kcal/mol for PON and PIN, respectively. The computational studies reveal that the presence of the Znα -bound water molecule depends on the structural feature of substrates characterized by P=O and P=S, which determines the hydrolytic mechanism and efficiency for the degradation of organophosphorus pesticides by PTE.

Conjugated Molecule-Assisted Supramolecular Hydrogel with Enhanced Antibacterial and Antibiofouling Properties.

The hydrogel using natural and synthetic polymers to create a cross-linking network has drawn attention in diverse bioapplications. However, inhibition of bacterial infection is still a challenge for hydrogel's wide application. In this work, we reported a supramolecular hydrogel with a good antibacterial property built from conjugated molecules. The water-soluble molecular 4,7-bis[9,9-di(2-carboxy-ethyl)-fluoren-2-yl]-2,1,3-benzothiadiazole (OFBTCOOH) physically linked with monomers via hydrophobic interaction. The free-radical polymerized poly(N-acryloyl glycinamide) was hydrogen-bond cross-linked by dual amides in the side chains to form a hydrogel. An adjustable micro-network was obtained by increasing OFBTCOOH with evidence of enhanced intermolecular interaction. The successfully integrated OFBTCOOH could be excited upon light irradiation. The energy of triplet-state excitons of OFBTCOOH transferred to the ground-state oxygen to produce singlet oxygen, which endowed the hydrogel with the antibacterial property. Meanwhile, the superhydrophilic surface of the hydrogel can bind water molecules to form a stable hydration layer, which acted as barriers to resist protein and bacterial adsorption and achieve the anti-biofouling goal. The ease in introducing conjugated polyelectrolytes may provide a formulation to functionalize hydrogels via various physical interactions.

Hyaluronic acid in gynecology and obstetrics

Introduction: Hyaluronic acid (HA) is a polysaccharide classified in the group of glycosaminoglycans. Naturally it occurs in the dermis and is responsible for the elasticity of the skin. In medicine, it can be found cross-linked, partially cross-linked or non-cross-linked, which is associated with different densities and the ability to bind water molecules. It (HA) is used in many areas, including ophthalmology, rheumatology, and dermatology. There are many studies and reports, that it can be used in gynecology and obstetrics in various diseases.Material and methods: The PubMed scientific base was reviewed in 2015-2022 using the keywords hyaluronic acid, gynecology, obstetrics.Results: Intrauterine adhesions are a complication of various procedures performed in the uterine cavity, from curettage to removal of the septum or uterine fibroids. Numerous studies suggest, that hyaluronic acid may be an effective agent in preventing formation of adhesions. For menopausal women, it may relieve symptoms associated with vaginal atrophy. Indocyanine green is used for intraoperative visualization of neoplastic tissues and used in case of cervical cancer. There are reports, that stating hyaluronic acid can increase stability of this substance, which can improve imaging. In the case of hyaluronic acid in the form of vaginal gel, a beneficial effect on hydration and sexual function of women both after childbirth and after menopause was noticed. There are reports of its use in prevention of ovarian failure after chemotherapy and its positive aspects in assisted reproductive techniques.Conclusions: Hyaluronic acid can be used in many gynecological and obstetric diseases, positively influencing the life of women in both fertility and sexual areas and also in the group of cancer patients. Therefore, further large, randomized, multicentre studies confirming action of this substance, determining its dose, method and schedule of administration are important.