Kinds Of Molecules Research Articles

The Insights of Microbes' Roles in Wound Healing: A Comprehensive Review.

A diverse range of normal flora populates the human skin and numbers are relatively different between individuals and parts of the skin. Humans and normal flora have formed a symbiotic relationship over a period of time. With numerous disease processes, the interaction between the host and normal flora can be interrupted. Unlike normal wound healing, which is complex and crucial to sustaining the skin’s physical barrier, chronic wounds, especially in diabetes, are wounds that fail to heal in a timely manner. The conditions become favorable for microbes to colonize and establish infections within the skin. These include secretions of various kinds of molecules, substances or even trigger the immune system to attack other cells required for wound healing. Additionally, the healing process can be slowed down by prolonging the inflammatory phase and delaying the wound repair process, which causes further destruction to the tissue. Antibiotics and wound dressings become the targeted therapy to treat chronic wounds. Though healing rates are improved, prolonged usage of these treatments could become ineffective or microbes may become resistant to the treatments. Considering all these factors, more studies are needed to comprehensively elucidate the role of human skin normal flora at the cellular and molecular level in a chronic injury. This article will review wound healing physiology and discuss the role of normal flora in the skin and chronic wounds.

Negative differential resistance in all-benzene molecule of trefoil knot

Based on first-principles calculations, the electronic transport of a recently synthesized all-benzene molecule of trefoil knot is investigated, by contacted with Au electrodes. Negative differential resistance behavior is observed. Further analysis shows that, it is resulted from the weaken of the states on the molecule modulated by the bias voltage, which suppresses the transmission eigenchannels and transmission peaks. Moreover, such a NDR behavior is also found in knot molecules with more benzene rings, indicating NDR is the intrinsic feature of such kind of molecules and robust to the number of benzene rings. These findings are expected to be extended to many other molecules with similar geometries, and may throw light on the development of future nanodevices.

Optical Detection of Streptavidin-Biotin Binding on Nanoporous Anodic Alumina Pore Surface

Nanoporous anodic alumina (NAA) is a material with a high interest in nanotechnology[1]. Its physical and chemical properties combined with a cost-effective and scalable production process make it a good candidate in many nanotechnologically-related applications. Its high and tuneable surface-to-volume ratio as well as its interesting optical properties[2] have been used as the basis of different biosensing schemes[3]. Biosensing, and specifically optical biosensing is of great interest in health and environmental applications. The reflection interference spectroscopy (RIfS) method based on NAA has demonstrated its ability in detecting many kinds of molecules (proteins, antibodies[4]).One of the molecular systems with interest in biotechnological applications is the streptavidin-biotin system. The high affinity between both molecules is exploited in many applications for the binding of different biological species. For this reason, we have studied the streptavidin-biotin binding event with NAA-based RIfS, as part of a biosensing process. In our study we assess the optimal conditions for real time monitoring of the different steps (covalent streptavidin bonding, surface passivation, biotin complexation). In order to establish such optimal conditions, we have chosen the protein thrombin as a model molecule to be detected.We prepared NAA with the usual anodization conditions under oxalic acid electrolyte to obtain porous layers with uniform pore diameter and with a thickness that permits the measurement with RIfS in a flow-cell where the different species in solution can be introduced. The experiments consisted of monitoring the change in effective optical thickness (EOT, the quantitative characteristic parameter obtained from RIfS) in the different steps of the biosensing process. The NAA pore surfaces were initially functionalized with (3-aminopropyl)triethoxysilane (APTES) with the carboxyl groups activated in order to form later a peptide bond with the streptavidin.One of the parameters to be optimized was the pore diameter. Furthermore, in order to study the ability of RIfS to detect the covalent streptavidin binding to the NAA pore surface, different concentrations of streptavidin were tested. Finally, the biosensing capabilities were evaluated by detecting biotinylated thrombin at different concentrations.An example of a complete experiment with all the steps in the streptavidin-biotinylated molecule attachment detection can be seen in Figure 1. After establishing a baseline with a PBS flow, streptavidin at 50 µg/ml is introduced in the RIfS setup and its covalent attachment to APTES is detected as an increase in EOT. Following this first step, PBS is introduced to wash away the non-specifically bound molecules and a 3% Bovine Serum Albumin (BSA) solution is flowed to passivate the remaining activated carboxyl groups of APTES and the remaining hydroxyl groups on the NAA pore surface. Such steps are detected by the RIfS procedure. Then, after a subsequent PBS wash, biotinylated thrombin at a concentration of 20 µg/ml is introduced causing a steady increase in EOT reaching a value of 3.5 nm above the initial one. The experiment in Figure 1 was repeated for different NAA pore sizes revealing a higher change in EOT for bigger pore sizes.An important parameter in the detection of the biotinylated molecules binding is the concentration at the streptavidin immobilization step. Thus, different streptavidin concentrations were tested in 60 nm pore diameter NAA. Results are summarized in Figure 2: for the highest concentrations (50 µg/ml) the attachment of streptavidin shows a two-phase curve with an initial phase with a faster increase in EOT and a second phase with a slower increase after an inflection point in the EOT versus time curve. Instead, for a small concentration (1 µg/ml) an initial fast increase is followed by a stabilization of the EOT signal. These two behaviors are associated with the attachment of streptavidin to the activated carboxyl of APTES for the initial fast EOT increase, while the subsequent slower increase can be explained by the aggregation of streptavidin through amine group binding.Finally, in order to demonstrate the capability of quantifying the attachment of biotinylated molecules to the NAA surface, the process was carried out using thrombin as the model molecule and for increasing concentrations. Figure 3 shows the change in EOT as a function of the thrombin concentration. It can be seen that RIfS based on NAA sensing platforms is able to quantify such attachment.[1] Josep Ferré-Borrull, et al., Nanomaterials, vol. 7, p. 5225 (2014).[2] Josep Ferré-Borrull et al., in NANOPOROUS ALUMINA: FABRICATION, STRUCTURE, PROPERTIES AND APPLICATIONS, Springer Series in Materials Science, vol. 219, p. 185 (2015).[3] Chris Eckstein, ACS Applied Materials and Interfaces, vol. 10, p.10571 (2018).[4] Gerard Macías, Analyst, vol. 140, p. 4848 (2015). Figure 1

The Study of Derivatization Prior MALDI MSI Analysis-Charge Tagging Based on the Cholesterol and Betaine Aldehyde.

Mass spectrometry imaging is a powerful tool for analyzing the different kinds of molecules in tissue sections, but some substances cannot be measured easily, due to their physicochemical properties. In such cases, chemical derivatization could be applied to introduce the charge into the molecule and facilitate its detection. Here, we study cholesterol derivatization with betaine aldehyde from tissue slices and evaluate how different sample preparation methods influence the signal from the derivatization product. In this study, we have tested different solutions for betaine aldehyde, different approaches to betaine aldehyde deposition (number of layers, deposition nozzle height), and different MALDI matrices for its analysis. As a result, we proved that the proposed approach could be used for the analysis of cholesterol in different tissues.

WAPL induces cervical intraepithelial neoplasia modulated with estrogen signaling without HPV E6/E7

Since cervical cancer still afflicts women around the world, it is necessary to understand the underlying mechanism of cervical cancer development. Infection with HPV is essential for the development of cervical intraepithelial neoplasia (CIN). In addition, estrogen receptor signaling is implicated in the development of cervical cancer. Previously, we have isolated human wings apart-like (WAPL), which is expected to cause chromosomal instability in the process of HPV-infected precancerous lesions to cervical cancer. However, the role of WAPL in the development of CIN is still unknown. In this study, in order to elucidate the role of WAPL in the early lesion, we established WAPL overexpressing mice (WAPL Tg mice) and HPV E6/E7 knock-in (KI) mice. WAPL Tg mice developed CIN lesion without HPV E6/E7. Interestingly, in WAPL Tg mice estrogen receptor 1 (ESR1) showed reduction as compared with the wild type, but cell growth factors MYC and Cyclin D1 controlled by ESR1 expressed at high levels. These results suggested that WAPL facilitates sensitivity of ESR1 mediated by some kind of molecule, and as a result, affects the expression of MYC and Cyclin D1 in cervical cancer cells. To detect such molecules, we performed microarray analysis of the uterine cervix in WAPL Tg mice, and focused MACROD1, a co-activator of ESR1. MACROD1 expression was increased in WAPL Tg mice compared with the wild type. In addition, knockdown of WAPL induced the downregulation of MACROD1, MYC, and Cyclin D1 but not ESR1 expression. Furthermore, ESR1 sensitivity assay showed lower activity in WAPL or MACROD1 downregulated cells than control cells. These data suggested that WAPL increases ESR1 sensitivity by activating MACROD1, and induces the expression of MYC and Cyclin D1. Therefore, we concluded that WAPL not only induces chromosomal instability in cervical cancer tumorigenesis, but also plays a key role in activating estrogen receptor signaling in early tumorigenesis.

SERS chips in an acupuncture needle for interaction in vivo and readout ex vivo of multiple parameters

AbstractOrganism is a complex molecular system, in which molecules interact and execute all life activities. It is still a challenge to detect multiple parameters in vivo simultaneously, which would overcome disadvantage of detection ex vitro. Here, a SERS chips in an acupuncture needle is presented. A magnetic pit in an acupuncture needle is constructed to anchor microscale magnetic SERS probes in it to form SERS chips. The SERS chips can be punctured into tissues with minimal invasion, and the magnetic pit protects the SERS probes from being erased. In the tissues, the SERS probes interact with respective targeted parameters, and SERS spectra of one kind of SERS probes are collected to indicate one kind of molecules after SERS chips were pulled out. Dozens or even hundreds of SERS probes can be integrated to collect information of dozens or even hundreds of parameters. Chips in an acupuncture needle would be a versatile platform to integrate various sensing materials for interaction in vivo and readout ex vivo of multiple parameters.

Neuromedin U, a Key Molecule in Metabolic Disorders.

Obesity is now a public health concern. The leading cause of obesity is an energy imbalance between ingested and expended calories. The mechanisms of feeding behavior and energy metabolism are regulated by a complex of various kinds of molecules, including anorexigenic and orexigenic neuropeptides. One of these neuropeptides, neuromedin U (NMU), was isolated in the 1980s, and its specific receptors, NMUR1 and NMUR2, were defined in 2000. A series of subsequent studies has revealed many of the physiological roles of the NMU system, including in feeding behavior, energy expenditure, stress responses, circadian rhythmicity, and inflammation. Particularly over the past decades, many reports have indicated that the NMU system plays an essential and direct role in regulating body weight, feeding behavior, energy metabolism, and insulin secretion, which are tightly linked to obesity pathophysiology. Furthermore, another ligand of NMU receptors, NMS (neuromedin S), was identified in 2005. NMS has physiological functions similar to those of NMU. This review summarizes recent observations of the NMU system in relation to the pathophysiology of obesity in both the central nervous systems and the peripheral tissues.

Structure, Z' = 2 Crystal Packing Features of 3-(2-Chlorobenzylidene)-5-(p-tolyl)furan-2(3H)-one.

3-(2-Chlorobenzylidene)-5-(p-tolyl)furan-2(3H)-one (1), C18H13ClO2, crystallizes with Z = 8 and Z′ = 2, and the structure at 100 K has orthorhombic (Pna21) symmetry. Each kind of molecule takes part in π–π stacking interactions to form infinite chains parallel to the c axis. We believe that the existence of two forms can be explained by the probable rotation around a single C–C bond. The quantum chemical modeling reveals that these molecules are almost equivalent energetically, and they can be described as the two most stable conformers (rotamers) with a minor rotational barrier of about 0.67 kcal/mol.

Structural aspects of an energy-based water classification index and the structure-dynamics link in glassy relaxation.

An energy-based structural indicator for water, [Formula: see text], has been recently introduced by our group. In turn, in this work we aim at: (1) demonstrating that [Formula: see text] is indeed able to correctly classify water molecules between locally structured tetrahedral (T) and locally distorted (D) ones, circumventing the usual problem of certain previous indicators of overestimating the distorted state; (2) correlating [Formula: see text] with dynamic propensity, a measure of the molecular mobility tendency, in order to seek for the existence of a connection between structure and dynamics within the supercooled regime. More specifically, in the first part of this work we will show that [Formula: see text] accurately discriminates between merely thermally deformed local molecular arrangements and truly distorted molecules (defects). This fact will be made evident not only from radial distribution function results but also from the dynamic propensity distributions of the different kinds of molecules. In turn, we shall devote the second part of this work to finding correlations between T and D molecules with low- and high-dynamic-propensity molecules, respectively, thus revealing the existence of a link between local structure and dynamics, while also making evident the dominant role of the D molecules (defects) in the structural relaxation. Moreover, the availability of a proper molecular classification technique will enable us to study the timescale of such influence of structure on dynamics by defining a modified dynamic propensity measure and by applying it to the structured and unstructured water molecular states.

Development of Drug Delivery Technology and Nanomedicine by Using Gold Nanoparticles

Nanomedicine is a new medical field involving the use of nanoparticles. Early examples of biocompatible nanomedicines include liposomes (Doxil®) and albumin nanoparticles (Abraxane®), and promising new nanomedicines include nanocarriers such as nanomicelles and nanoemulsions. A new trend towards the use of metal-based nanoparticles, including gold nanoparticles, has led to global clinical trials. These particles exhibit novel properties compared to conventional nanomedicines such as liposomes and albumin nanoparticles. These properties hold promise for nanomedicines, and thus the biodistribution and pharmacokinetics of metal-based nanoparticles should be carefully investigated. This had led to an increasing number of clinical trials investigating metal nanoparticles and inorganic nanoparticles. The present review evaluates multi-functional gold nanoparticles described in recent articles and shows that the unique properties of gold nanoparticles are applicable for not only drug delivery, but also for imaging. The combined therapeutic modality between therapeutics and diagnostics is called "theranostics" and is promising for future personalized cancer therapy. This review also introduces recent research from our laboratory involving the use of various kinds of molecules [polyethylene glycol (PEG), drug/cyclodextrin inclusion complexes, biosimilars and small interfering (siRNAs)] loaded onto and/or conjugated with gold nanoparticles.

Front Cover: (p‐(Diphenylarsino)phenyl)diphenylphosphine as a Novel Template for Heterodinuclear Complexes (2/2021)

The Front Cover shows characteristic features of (p-(diphenylarsino)phenyl)diphenylphosphine, in which the phosphorus atom preferentially coordinates to Lewis acids such as borane and metals (Au and Pt). The tilted balances represent about its asymmetric coordination behavior. This kind of molecule can be utilized as a template ligand to precisely arrange various Lewis acids, particularly transition metals. More information can be found in the Full Paper by Hiroaki Imoto, Kensuke Naka et al.

Growth inhibition effect on Trypanosoma brucei gambiense by the oxidative stress supplied from low-temperature plasma at atmospheric pressure

Trypanosoma brucei (Tb) is a pathogenic protozoan causing sleeping sickness in humans. Despite little knowledge of how the produced reactive oxygen species (ROS) kills this protozoan, the research on the killing mechanism using chemical compounds and the phagosome in the macrophages has suggested that the protozoan is highly susceptible to the increased oxidative stress. Because the prescribed drug can react with various kinds of molecules and the second produced intermediate compounds, in this study, we clarified the immediate killing effect on Tb in the condition of increased oxidative stress using a low-temperature plasma at atmospheric pressure (LTP) equipment. Results Show the significant growth inhibition of Tb in the LTP-treated medium, the loss of morphological homeostasis with twisted to puffed appearance, and demonstrated the swelled changes on mitochondria and endoplasmic reticulum. In conclusion, this study revealed how the increased oxidative stress kills Tb using LTP technology.

Ultra-cold long-range Rydberg-ground molecules

<sec> Ultra-cold long-range Rydberg-ground molecule consisting of a Rydberg atom and one or more ground-state atoms is formed by low-energy scattering between the Rydberg electron and ground-state atoms located inside the Rydberg electron’s wave function. The low-energy scattering interaction, initially investigated by Fermi and Omont, has been predicted to lead to molecular binding in a novel type of Rydberg molecules, including the trilobite and butterfly molecules. Their unconventional binding mechanism, which is unlike covalent, or ionic, or van der Waals bonds, results in loosely bound molecules with bond lengths on the order of thousands of Bohr radius. This kind of molecule with large size and huge permanent electric dipole moment is a good candidate for realizing the certain strongly correlated many-body gases and for quantum information processing, as well as for dipolar quantum gases and spin systems with long-range interactions. Consequently, these molecules have received considerable attention in recent years.</sec><sec>In this paper, we review the recent theoretical and experimental investigations of ultra-cold long-range Rydberg-ground molecules, including the scattering interaction between the Rydberg electron and ground-state atom and the resulting adiabatic potential curves, experimental observations of photo-associated Rydberg-ground molecules spectra, as well as the measurements of permanent electric dipole moment. Ultra-cold long-range Rydberg-ground molecules are prepared by photoassociation in a high-density cold atom sample. Therefore, the Rydberg electron can bind several ground-state atoms to form a polyatomic Rydberg-ground molecule. The permanent molecular electric-dipole moments are revealed by spectral line broadening in the electric fields. The latest research pointed out that the permanent electric dipole moments of the Cs <i>n</i>D<sub><i>J</i></sub> -type Rydberg-ground molecules are negative, which is different from the previous reports (the electric dipole moments are positive). The negative sign reflects a deficiency of Rydberg-electron density near the ground-state perturber, which is caused by electronic configuration mixing. </sec>

Minimizing isotropic and deviatoric membrane energy - An unifying formation mechanism of different cellular membrane nanovesicle types.

Tiny membrane-enclosed cellular fragments that can mediate interactions between cells and organisms have recently become a subject of increasing attention. In this work the mechanism of formation of cell membrane nanovesicles (CNVs) was studied experimentally and theoretically. CNVs were isolated by centrifugation and washing of blood cells and observed by optical microscopy and scanning electron microscopy. The shape of the biological membrane in the budding process, as observed in phospholipid vesicles, in erythrocytes and in CNVs, was described by an unifying model. Taking the mean curvature h and the curvature deviator d of the membrane surface as the relevant parameters, the shape and the distribution of membrane constituents were determined theoretically by minimization of membrane free energy. Considering these results and previous results on vesiculation of red blood cells it was interpreted that the budding processes may lead to formation of different types of CNVs as regards the compartment (exo/endovesicles), shape (spherical/tubular/torocytic) and composition (enriched/depleted in particular kinds of molecules). It was concluded that the specificity of pinched off nanovesicles derives from the shape of the membrane constituents and not primarily from their chemical identity, which explains evidences on great heterogeneity of isolated extracellular vesicles with respect to composition.

Endocrine Therapy for the Functional Recovery of Spinal Cord Injury.

Spinal cord injury (SCI) is a major cause of physical disability and leads to patient dissatisfaction with their quality of life. Patients with SCI usually exhibit severe clinical symptoms, including sensory and motor dysfunction below the injured levels, paraplegia, quadriplegia and urinary retention, which can exacerbate the substantial medical and social burdens. The major pathological change observed in SCI is inflammatory reaction, which induces demyelination, axonal degeneration, and the apoptosis and necrosis of neurons. Traditional medical treatments are mainly focused on the recovery of motor function and prevention of complications. To date, numerous studies have been conducted to explore the cellular and molecular mechanism of SCI and have proposed lots of effective treatments, but the clinical applications are still limited due to the complex pathogenesis and poor prognosis after SCI. Endocrine hormones are kinds of molecules that are synthesized by specialized endocrine organs and can participate in the regulation of multiple physiological activities, and their protective effects on several disorders have been widely discussed. In addition, many studies have identified that endocrine hormones can promote nerve regeneration and functional recovery in individuals with central nervous system diseases. Therefore, studies investigating the clinical applications of endocrine hormones as treatments for SCI are necessary. In this review, we described the neuroprotective roles of several endocrine hormones in SCI; endocrine hormone administration reduces cell death and promotes functional repair after SCI. We also proposed novel therapies for SCI.

Surface-Engineered Cubosomes Serve as a Novel Vaccine Adjuvant to Modulate Innate Immunity and Improve Adaptive Immunity in vivo.

ObjectiveRecent studies have revealed the adjuvant activity of cubosomes and their potential utility as an antigen delivery system. In this study, to further enhance the adjuvant activity of cubosomes, two cationic polymers are modified on the surface of cubosomes.MethodsHere, we exploit the effects of surface chemistry on the adjuvant activity of Ganoderma lucidum polysaccharide cubosomes (GLPC) by placing two kinds of molecules, that is, cetyltrimethylammonium bromide (CTAB) and poly(diallydimethyl ammonium chloride) (PDDAC), on their surface.ResultsCTAB- or PDDAC-modified GLPC were found to significantly promote humoral and cellular immune responses, as well as the proliferation of CD3+ CD4+ or CD3+ CD8+T cells through the powerful activation of dendritic cells (DCs). The enhanced immune responses of PDDAC-modified GLPC might be attributed to the maturation of DCs into draining lymph nodes and the activation of spleen and cytokines in serum.ConclusionPDDAC modification is beneficial for enhancing humoral and cellular immune response, suggesting that PDDAC-GLPC-OVA has the ability to be a potential adjuvant for vaccine.

Recent advances in nanoporous AAO based substrates for surface-enhanced raman scattering

Abstract Nanoporous anodic aluminium oxide (AAO) has become one of the most attractive engineered template for sensing, drug delivery, catalysis, photonics, electronics, energy generation, and storage applications. The formation of AAO is based on the low-cost self-ordering anodization of pure aluminium, which provides perpendicularly aligned, well-organized nanoporous structures with hexagonal symmetry. Due to its distinctive physical and chemical characteristics, it has been widely examined for the development of advanced, cheap, reproducible, and portable sensing devices. On the other hand, from the last few decades, surface-enhanced Raman scattering (SERS) spectroscopy has drawn a wide range of attention because of its label-free detection capability and extreme sensitivity towards the detection of a lower limit of analytes. The key barrier to the extensive use of SERS for regular recognition is the lack of reproducibility of the substrate (periodicity, surface roughness, thickness) as well as the signal (wavelength position and intensity) which are significant for SERS applications. This paper provides a review of AAO templates for the fabrication of reproducible SERS active substrate for sensing various kind of molecules.

Elevating the density and intensity of hot spots by repeated annealing for high-efficiency SERS.

The simultaneous output of highly sensitive and reproducible signals for surface-enhanced Raman spectroscopy (SERS) technology remains difficult. Here, we propose a two-dimensional (2D) composite structure using the repeated annealing method with MoS2 film as the molecular adsorbent. This method provides enlarged Au nanoparticle (NP) density with much smaller gap spacing, and thus dramatically increases the density and intensity of hot spots. The MoS2 films distribute among the hot spots, which is beneficial for uniform molecular adsorption, and further increases the sensitivity of the SERS substrate. Three kinds of molecules were used to evaluate the SERS substrate. Ultra-sensitive, highly repetitive, and stable SERS signals were obtained, which would promote the application process of SERS technology in quantitative analysis and detection.

Development and Reorganization of Orientation Representation in the Cat Visual Cortex: Experience-Dependent Synaptic Rewiring in Early Life.

To date, numerous mathematical models have been proposed on the basis of some types of Hebbian synaptic learning to account for the activity-dependent development of orientation maps as well as neuronal orientation selectivity. These models successfully reproduced orientation map-like spatial patterns. Nevertheless, we still have questions: (1) How does synaptic rewiring occur in the visual cortex during the formation of orderly orientation maps in early life? (2) How does visual experience contribute to the maturation of orientation selectivity of visual cortical neurons and reorganize orientation maps? (3) How does the sensitive period for orientation plasticity end? In this study, we performed animal experiments and mathematical modeling to understand the mechanisms underlying synaptic rewiring for experience-dependent formation and reorganization of orientation maps. At first, we visualized orientation maps from the intrinsic signal optical imaging in area 17 of kittens reared under single-orientation exposure through cylindrical-lens-fitted goggles. The experiments revealed that the degree of expansion of cortical domains representing the experienced orientation depends on the age at which the single-orientation exposure starts. As a result, we obtained the sensitive period profile for orientation plasticity. Next, we refined our previously proposed mathematical model for the activity-dependent self-organization of thalamo-cortical inputs on the assumption that rewiring is caused by the competitive interactions among transient synaptic contacts on the same dendritic spine. Although various kinds of molecules have been reported to be involved in such interactions, we attempt to build a mathematical model to describe synaptic rewiring focusing on brain-derived neurotrophic factor (BDNF) and its related molecules. Performing computer simulations based on the refined model, we successfully reproduced orientation maps reorganized in kittens reared under single-orientation exposure as well as normal visual experience. We also reproduced the experimentally obtained sensitive period profile for orientation plasticity. The excellent agreement between experimental observations and theoretical reproductions suggests that the BDNF-induced competitive interaction among synaptic contacts from different axons on the same spine is an important factor for the experience-dependent formation and reorganization of orientation selectivity and orientation maps.

Organoferroelasticity Mediated by Water of Crystallization

Despite the general conception of brittleness, organic single crystals composed of various kinds of molecules can show ferroelasticity by mechanical twinning. This is attributed to flexibilities in molecular structures, e.g., conformation, and noncovalent bonds, e.g., length and angle. Herein, we find ferroelasticity by mechanical twinning mediated by water of crystallization in a single crystal of a zwitterion: sulfanilic acid monohydrate. Shaping of an organic single crystal is demonstrated ferroelastically from linear to bent shape and from contracted to elongated shape. Rotation of sulfonate anions along with recombination and changes in lengths and angles in flexible hydrogen bonds of small water molecules helps ferroelastic mechanical twinning. Our findings demonstrate designability of mechanically twinnable organic crystals from the viewpoints of organic chemistry and crystal engineering based on hydrogen bonds.