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Amuso D, Medoro A, Scapagnini G, Gambacorta A, Davinelli S, Iorio EL, Bonetti LR, Sbarbati A. A pilot study on the efficacy of a seaweed mud application in the treatment of cellulite. J Cosmet Dermatol 2024; 23:2181-2189. [PMID: 38450959 DOI: 10.1111/jocd.16268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 02/05/2024] [Accepted: 02/23/2024] [Indexed: 03/08/2024]
Abstract
BACKGROUND Cellulite represents a common multi-factorial condition that affects nearly all women and is now recognized as a clinical condition associated with systemic factors and negative psychological effects. Several noninvasive and minimally invasive treatments were developed during the last few years, but limited evidence supports many of them due to lack of evidence, insufficient participants, and potential adverse effects. METHODS This study aimed to evaluate the efficacy of a seaweed mud application in improving both the structure and function of tissues affected by cellulite. Sixty women with cellulite underwent 4-week applications of seaweed mud on the buttocks and thighs. The following assessments were performed at baseline and after the last treatment: photographic, clinical, and anthropometric evaluation; tests for elasticity and hydration; ultrasonography of cellulite nodules; and cellulite biopsies in the trochanteric region. Patient satisfaction was assessed using a 5-point Likert-scale questionnaire. RESULTS The treatment resulted in a significant improvement in the severity of cellulite severity between the initial assessment and the 4-week follow-up, with enhanced structure, elasticity, and hydration of the affected tissues. Microscopic analysis of the cellulite biopsies revealed a significant restoration of dermal organization with induced collagen synthesis and reduced inflammation, edema, and lipid deposition following the 4-week seaweed mud applications. Additionally, the treatment led to a remarkable improvement in comfort and satisfaction as well as a reduction in body circumferences. CONCLUSIONS The cosmetic application of seaweed mud has proven to be a safe, non-invasive treatment for improving the tissue alterations characteristic of cellulite.
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Georgiev A, Kaneva M, Shikova L, Mateeva P, Tchekalarova J, Antonova M. In Vitro Effects of Fentanyl on Aortic Viscoelasticity in a Rat Model of Melatonin Deficiency. Int J Mol Sci 2024; 25:5669. [PMID: 38891855 PMCID: PMC11171473 DOI: 10.3390/ijms25115669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 05/14/2024] [Accepted: 05/19/2024] [Indexed: 06/21/2024] Open
Abstract
Melatonin influences arterial biomechanics, and its absence could cause remodeling of the arterial wall, leading to increased stiffness. Direct effects of fentanyl on the aortic wall have also been observed previously. This study aimed to evaluate in vitro the effects of fentanyl on aortic viscoelasticity in a rat model of melatonin deficiency and to test the hypothesis that melatonin deficiency leads to increased arterial wall stiffness. The viscoelasticity was estimated in strip preparations from pinealectomized (pin, melatonin deficiency) and sham-operated (sham, normal melatonin) adult rats using the forced oscillations method. In the untreated aortic wall pin, the viscoelasticity was not significantly altered. However, combined with 10-9 M fentanyl, the pin increased the natural frequency (f0) and modulus of elasticity (E') compared to the sham-operated. Independently, fentanyl treatment decreased f0 and E' compared separately to untreated sham and pin preparations. The effects of fentanyl were neither dose-dependent nor affected by naloxone, suggesting a non-opioid mechanism. Furthermore, an independent effect of naloxone was also detected in the normal rat aortic wall, resulting in reduced E'. Additional studies are needed that may improve the clinical decisions for pain management and anesthesia for certain patients with co-occurring chronic low levels of blood plasma melatonin and some diseases.
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Guzman V BM, De La Torre I MH, Frausto-Reyes C. Impact of the preservation media on ex vivo bone samples for full field mechanical testing. APPLIED OPTICS 2024; 63:3745-3752. [PMID: 38856336 DOI: 10.1364/ao.512047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 04/13/2024] [Indexed: 06/11/2024]
Abstract
The preservation method to store bone tissue for posterior analysis is a widespread practice. However, the method's potential influence on the material's mechanical properties is often overlooked during single-point experimentation. Saline and formaldehyde solutions are the most common among the employed preservation media. A full field analysis of the mice femoral bone deformation using non-destructive optical techniques is conducted to assess the influence of the storage media on the viscoelastic properties of the tissue. Three different groups are subjected to a standard three-point bending test. The first group is the control, with fresh post-mortem samples. The second and third groups used saline and formaldehyde solutions, respectively. During the mechanical test, the bone's surface and internal deformation are monitored simultaneously using digital holographic interferometry and Fourier-domain optical coherence tomography. A mechanical comparison among the three groups is presented. The results show that after 48 h of immersion in saline solution, the mice bones keep their viscoelastic behavior similar to fresh bones. Meanwhile, 48 h in formaldehyde modifies the response and affects the marrow structure. The high sensitivity of the optical phase also makes it possible to observe changes in the anisotropy of the samples. As a comparison, Raman spectroscopy analyzes the three bone groups to prove that the preservation media does not affect a single-point inspection.
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Yoon EJ, Kwon EH, Kim JH, Delacruz J, Symons TB, Lee S, Park D. Influence of cosmetic foundation cream on skin condition during treadmill exercise. J Cosmet Dermatol 2024; 23:1884-1890. [PMID: 38444348 DOI: 10.1111/jocd.16205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/11/2024] [Accepted: 01/22/2024] [Indexed: 03/07/2024]
Abstract
BACKGROUND There is a growing trend of individuals wearing cosmetics while participating in physical activities. Nonetheless, there remains a need for further understanding regarding the effects of makeup on the facial epidermis during exercise, given the existing knowledge gaps. PURPOSE This study aimed to evaluate the effects of a cosmetic foundation cream on skin conditions during physical activity. METHODS Forty-three healthy college students, 20 males (26.3 ± 1.5 years) and 23 females (23.1 ± 1.0 years), were enrolled in this study. Foundation cream was applied to participants on half of the face in two different areas (MT: makeup T zone and MU: makeup U zone). The other half of the face served as internal control (T: non-makeup T zone and U: non-makeup U zones). Skin levels of moisture, elasticity, pore, sebum, and oil were measured using a skin analysis device (Aramhuvis, Gyeonggi, Republic of Korea) before and after a 20-min treadmill exercise. Paired t-test and independent t-test were performed for skin condition measurements at pre- and postexercise. RESULTS The skin moisture levels in both the T and MT significantly increased after exercise (p < 0.05) (pre-T: 24.5 ± 1.3, post-T: 38.5 ± 3.5 and pre-MT: 18.7 ± 0.7, post-MT: 40.4 ± 4.8). Elasticity also significantly improved in both the T and MT (p < 0.05) (pre-T: 25.6 ± 1.3, post-T: 41.5 ± 3.5 and pre-MT: 20.0 ± 0.9, post-MT: 41.7 ± 3.7). The size of the pores in the T zone observed a significant increase after exercise (p < 0.05) (pre-T: 41.7 ± 2.1, post-T: 47.8 ± 2.4). The sebum levels in the T zone exhibited a reduction following physical activity, whereas there was a notable increase in sebum levels in the makeup zones (p < 0.05) (pre-MT: 2.4 ± 0.7, post-MT:4.2 ± 0.8 and pre MU 1.8 ± 0.34, post MU 4.9 ± 0.9). The oil level was increased in the non-makeup zones (pre-T: 6.1 ± 1.4, post-T: 11.8 ± 2.0 and pre-U: 7.3 ± 1.5, post-U: 11.9 ± 1.9; p < 0.05) and decreased in the makeup zones (pre-MT: 13.3 ± 1.9, post-MT: 7.4 ± 2.3 and pre-MU: 22.1 ± 2.4, post-MU: 3.2 ± 1.0; p < 0.05). CONCLUSIONS The findings suggest that using foundation cream during aerobic exercise can reduce skin oil, causing dryness. Additionally, makeup can clog pores and increase sebum production. Therefore, wearing makeup may not be recommended for people with dry skin conditions based on the results of the current study. This research offers important insights to the public, encouraging them to consider the possible consequences of using makeup while exercising.
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Oh S, Kim H, Kim M, Jin X, Zheng S, Yi TH. The effects of Jawoongo soap on skin improvement. J Cosmet Dermatol 2024; 23:1862-1874. [PMID: 38275088 DOI: 10.1111/jocd.16199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/11/2024] [Accepted: 01/16/2024] [Indexed: 01/27/2024]
Abstract
BACKGROUND Jawoongo is used to treat and prevent skin issues such as dry and keratinization disorders, burns, trauma, pigmentation, scarring, and inflammatory skin conditions. In this study, the efficacy and safety of 0.47% Jawoongo extract-containing soap (JAUN-CS) were assessed in terms of skin improvement effects such as cleansing, moisturizing, sebum secretion management, and skin elasticity enhancement. METHODS Twenty healthy adult men and women aged 20-60 years old took part in the study. Before and after using JAUN-CS, the participants were divided into groups, and various skin improvement effects were measured utilizing machines such as the Corneometer, Tewameter TM 300, and Visioscan. A dermatologist analyzed the product's safety in accordance with Frosch & Kligman and the Cosmetic, Toiletry, and Fragrance Association (CTFA) rules. RESULTS Using JAUN reduced the amount of base and point makeup by 25.7% and 76.7%, respectively. Also, JAUN showed a great facial exfoliation effect by removing the old and lifted skin keratins by 84.7% and 20.3%, respectively. Impurities in facial pores decreased by 58%, too. Furthermore, JAUN increased the moisture content of deep skin and skin surface by 3.5% and 74.0%, and skin elasticity by 2.8%. Skin tone, skin texture, skin radiance, and skin barrier all showed improvements of 3.3%, 20.0%, 15.0%, and 115.2%, respectively. Lastly, cleansing with JAUN successfully enhanced the condition of the youth triangle by 7.6%, while TEWL significantly decreased by 52.7%. Neither the JAUN nor the control group soap showed any adverse reactions, such as erythema or allergies, during the testing period. CONCLUSIONS The results of this study demonstrated that JAUN is safe for human use and has various skin-improving properties, making Jawoongo a promising natural material for the development of functional cosmetics in the future.
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Sayin N, Kocak I, Pehlivanoğlu S, Pekel G, Er A, Bayramoğlu SE, Aydin A. A quantitative sonoelastography evaluation of ocular and periocular elasticity after intravitreal ranibizumab injection. J Fr Ophtalmol 2023; 46:1030-1038. [PMID: 37598105 DOI: 10.1016/j.jfo.2023.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 01/28/2023] [Accepted: 03/05/2023] [Indexed: 08/21/2023]
Abstract
PURPOSE We evaluated changes in ocular and periocular elasticity by ultrasound (US) elastography in intravitreal ranibizumab-treated eyes and the healthy fellow eyes of patients with neovascular AMD. METHODS The study was performed on 52 eyes of 26 volunteers who ranged in age from 59 to 89 (mean 72±7.78) years old. The study group consisted of the patients with neovascular AMD treated with intravitreal ranibizumab. The fellow eyes (without choroidal neovascularization) of the study group were selected as the control group. All patients were examined with sonoelastography before intravitreal injection and at 1day, 1week, and 1month after intravitreal injection. All images were acquired with a Toshiba Aplio 500 ultrasound system (Tokyo, Japan) including software with a combined autocorrelation method and a multifrequency linear probe. The elastography values of the anterior vitreous (AV), posterior vitreous (PV), retina-choroid-sclera complex (RCS), retrobulbar fat tissue (RF), optic nerve head (ONH) and retrobulbar optic nerve (RON) were measured in each eye. RESULTS There were 13 male (50%) and 13 female (50%) participants in our study. Anterior vitreous, posterior vitreous, RCS, retrobulbar fat tissue, ONH, and RON US elastography values were similar in both groups (P˃0.05 for all). On the other hand, there was a positive correlation between the difference between baseline and 1-month PV sonoelastography values and age (r=0.47, P=0.035). CONCLUSION A single dose intravitreal Ranibizumab (Lucentis®, Genentech, USA) injection does not alter the elasticity of ocular and periocular structures.
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Cornette P, Jaabar IL, Dupres V, Werthel JD, Berenbaum F, Houard X, Landoulsi J, Nourissat G. Impact of Collagen Crosslinking on Dislocated Human Shoulder Capsules-Effect on Structural and Mechanical Properties. Int J Mol Sci 2022; 23:ijms23042297. [PMID: 35216412 PMCID: PMC8877509 DOI: 10.3390/ijms23042297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/14/2022] [Accepted: 02/15/2022] [Indexed: 02/04/2023] Open
Abstract
Classical treatments of shoulder instability are associated with recurrence. To determine whether the modification of the capsule properties may be an alternative procedure, the effect of crosslinking treatment on the structure and mechanical properties of diseased human shoulder capsules was investigated. Joint capsules harvested from patients during shoulder surgery (n = 5) were treated or not with UV and/or riboflavin (0.1%, 1.0% and 2.5%). The structure and the mechanical properties of the capsules were determined by atomic force microscopy. The effect of treatments on cell death was investigated. Collagen fibrils were well-aligned and adjacent to each other with a D-periodicity of 66.9 ± 3.2 nm and a diameter of 71.8 ± 15.4 nm in control untreated capsules. No effect of treatments was observed on the organization of the collagen fibrils nor on their intrinsic characteristics, including D-periodicity or their mean diameter. The treatments also did not induce cell death. In contrast, UV + 2.5% riboflavin induced capsule stiffness, as revealed by the increased Young's modulus values (p < 0.0001 for each patient). Our results showed that the crosslinking procedure changed the biomechanics of diseased capsules, while keeping their structural organisation unchanged at the single fibril level. The UV/riboflavin crosslinking procedure may be a promising way to preserve the functions of collagen-based tissues and tune their elasticity for clinically relevant treatments.
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Ahn J, Lamm SH, Ferdosi H, Boroje IJ. Aortic Elasticity and Arsenic Exposure: A Step Function rather than a Linear Function. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2021; 41:2293-2300. [PMID: 33998018 DOI: 10.1111/risa.13756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 02/26/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
While the dose-response relationship for the carcinogenic effects of arsenic exposure indicates nonlinearity with increases only above about 150 μg/L arsenic in drinking water, similar analyses of noncarcinogenic effects of arsenic exposure remain to be conducted. We present here an alternative analysis of data on a measure of aortic elasticity, a risk factor for hypertension, and its relationship to urinary arsenic levels. An occupational health study from Ankara, Turkey by Karakulak et al. compared urinary arsenic levels and a measure of aortic elasticity (specifically, aortic strain) in workers with a linear no-threshold model. We have examined these data with three alternative models-a fitted step-function, a stratified, and a weighted linear regression model. Discontinuity within the data revealed two subsets of data, one for workers with urinary arsenic levels ≤ 160 μg/L whose mean aortic strain level was 11.3% and one for workers with arsenic levels > 160 μg/L whose mean aortic stain level was 5.33 % (p < 0.0001). Several alternative models were examined that indicated the best model to be the threshold model with a threshold at a urinary arsenic level of 160 μg/L. Observation of a discontinuity in the data revealed their better fit to a threshold model (at a urinary arsenic level of 160 μg/L) than to a linear-no threshold model. Examinations with alternative models are recommended for studies of arsenic and hypertension and possibly other noncarcinogenic effects.
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Phan TKT, Do TL, Tachibana K, Kihara T. Alpha-mangostin dephosphorylates ERM to induce adhesion and decrease surface stiffness in KG-1 cells. Hum Cell 2021; 35:189-198. [PMID: 34817798 DOI: 10.1007/s13577-021-00651-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 11/18/2021] [Indexed: 11/30/2022]
Abstract
Surface stiffness is a unique indicator of various cellular states and events and needs to be tightly controlled. α-Mangostin, a natural compound with numerous bioactivities, reduces the mechanical stiffness of various cells; however, the mechanism by which it affects the actin cytoskeleton remains unclear. We aimed to elucidate the mechanism underlying α-mangostin activity on the surface stiffness of leukocytes. We treated spherical non-adherent myelomonocytic KG-1 cells with α-mangostin; it clearly reduced their surface stiffness and disrupted their microvilli. The α-mangostin-induced reduction in surface stiffness was inhibited by calyculin A, a protein phosphatase inhibitor. α-Mangostin also induced KG-1 cell adhesion to a fibronectin-coated surface. In KG-1 cells, a decrease in surface stiffness and the induction of cell adhesion are largely attributed to the dephosphorylation of ezrin/radixin/moesin proteins (ERMs); α-mangostin reduced the levels of phosphorylated ERMs. It further increased protein kinase C (PKC) activity. α-Mangostin-induced KG-1 cell adhesion and cell surface softness were inhibited by the PKC inhibitor GF109203X. The results of the present study suggest that α-mangostin decreases stiffness and induces adhesion of KG-1 cells via PKC activation and ERM dephosphorylation.
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Ansary TM, Hossain MR, Kamiya K, Komine M, Ohtsuki M. Inflammatory Molecules Associated with Ultraviolet Radiation-Mediated Skin Aging. Int J Mol Sci 2021; 22:ijms22083974. [PMID: 33921444 PMCID: PMC8069861 DOI: 10.3390/ijms22083974] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/05/2021] [Accepted: 04/06/2021] [Indexed: 12/18/2022] Open
Abstract
Skin is the largest and most complex organ in the human body comprised of multiple layers with different types of cells. Different kinds of environmental stressors, for example, ultraviolet radiation (UVR), temperature, air pollutants, smoking, and diet, accelerate skin aging by stimulating inflammatory molecules. Skin aging caused by UVR is characterized by loss of elasticity, fine lines, wrinkles, reduced epidermal and dermal components, increased epidermal permeability, delayed wound healing, and approximately 90% of skin aging. These external factors can cause aging through reactive oxygen species (ROS)-mediated inflammation, as well as aged skin is a source of circulatory inflammatory molecules which accelerate skin aging and cause aging-related diseases. This review article focuses on the inflammatory pathways associated with UVR-mediated skin aging.
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Prokopová A, Pavlačková J, Mokrejš P, Gál R. Collagen Hydrolysate Prepared from Chicken By-Product as a Functional Polymer in Cosmetic Formulation. Molecules 2021; 26:molecules26072021. [PMID: 33916274 PMCID: PMC8037141 DOI: 10.3390/molecules26072021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 11/16/2022] Open
Abstract
Chicken stomachs can be processed into collagen hydrolysate usable in cosmetic products. The aim of the study was to verify the effects of a carbopol gel formulation enriched with 1.0% (w/w) chicken hydrolysate on the properties of the skin in the periorbital area after regular application twice a day for eight weeks in volunteers ageed 50 ± 9 years. Skin hydration, transepidermal water loss (TEWL), skin elasticity and skin relief were evaluated. Overall, skin hydration increased by 11.82% and 9.45%, TEWL decreased by 25.70% and 17.80% (always reported for the right and left area). Generally, there was an increase in skin elasticity, a decrease in skin roughness, as the resonance times decreased by 85%. The average reduction of wrinkles was 35.40% on the right and 41.20% on the left. For all results, it can be seen that the longer the cosmetic gel formulation is applied, the better the results. Due to the positive effect on the quality and functionality of the skin, it is possible to apply the cosmetic gel formulation in the periorbital area. The advantage of the product with chicken collagen hydrolysate is also the biocompatibility with the skin and the biodegradability of the formulation.
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Lee S, Lee HS, Chung JJ, Kim SH, Park JW, Lee K, Jung Y. Enhanced Regeneration of Vascularized Adipose Tissue with Dual 3D-Printed Elastic Polymer/dECM Hydrogel Complex. Int J Mol Sci 2021; 22:ijms22062886. [PMID: 33809175 PMCID: PMC7999751 DOI: 10.3390/ijms22062886] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 12/11/2022] Open
Abstract
A flexible and bioactive scaffold for adipose tissue engineering was fabricated and evaluated by dual nozzle three-dimensional printing. A highly elastic poly (L-lactide-co-ε-caprolactone) (PLCL) copolymer, which acted as the main scaffolding, and human adipose tissue derived decellularized extracellular matrix (dECM) hydrogels were used as the printing inks to form the scaffolds. To prepare the three-dimensional (3D) scaffolds, the PLCL co-polymer was printed with a hot melting extruder system while retaining its physical character, similar to adipose tissue, which is beneficial for regeneration. Moreover, to promote adipogenic differentiation and angiogenesis, adipose tissue-derived dECM was used. To optimize the printability of the hydrogel inks, a mixture of collagen type I and dECM hydrogels was used. Furthermore, we examined the adipose tissue formation and angiogenesis of the PLCL/dECM complex scaffold. From in vivo experiments, it was observed that the matured adipose-like tissue structures were abundant, and the number of matured capillaries was remarkably higher in the hydrogel–PLCL group than in the PLCL-only group. Moreover, a higher expression of M2 macrophages, which are known to be involved in the remodeling and regeneration of tissues, was detected in the hydrogel–PLCL group by immunofluorescence analysis. Based on these results, we suggest that our PLCL/dECM fabricated by a dual 3D printing system will be useful for the treatment of large volume fat tissue regeneration.
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Makino ET, Kadoya K, Chung R, Jiang L, Mikati M, Mehta RC. Efficacy and Tolerability of a Novel Topical Treatment for Neck: A Randomized, Double-blind, Regimen-Controlled Study. J Drugs Dermatol 2021; 20:184-191. [PMID: 33538566 DOI: 10.36849/jdd.5819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The neck plays a telling role as an age indicator. Due to its anatomy and function, neck skin ages differently than facial skin and special considerations need to be taken when providing treatment. A randomized, double-blind, regimen-controlled study was conducted to assess the efficacy and tolerability of a novel topical cosmetic cream (NCC) specifically tailored to address the signs of skin aging of the neck and décolletage. Twice daily application of NCC significantly improved skin sagging/laxity of the neck as well as the appearance of fine and coarse lines/wrinkles, crepiness, tactile roughness, overall skin texture, hyperpigmentation, skin tone evenness, and radiance. NCC also significantly improved the appearance of fine and coarse lines/wrinkles, tactile roughness, hyperpigmentation, skin tone evenness, and radiance of the décolletage. Investigator assessments were corroborated by objective cutometer measurements that demonstrated improved skin firmness and elasticity. In vitro analysis in human 3D skin models show that stimulation of neocollagenesis and neoelastogenesis as well as support of cellular proteostasis through proteasome and autophagy activation are potential mechanisms of action for the observed clinical outcomes. J Drugs Dermatol. 2021;20(2):184-191. doi:10.36849/JDD.5819
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Zemljič Jokhadar Š, Stojković B, Vidak M, Sorčan T, Liovic M, Gouveia M, Travasso RDM, Derganc J. Cortical stiffness of keratinocytes measured by lateral indentation with optical tweezers. PLoS One 2021; 15:e0231606. [PMID: 33382707 PMCID: PMC7774922 DOI: 10.1371/journal.pone.0231606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 12/04/2020] [Indexed: 01/20/2023] Open
Abstract
Keratin intermediate filaments are the principal structural element of epithelial cells. Their importance in providing bulk cellular stiffness is well recognized, but their role in the mechanics of cell cortex is less understood. In this study, we therefore compared the cortical stiffness of three keratinocyte lines: primary wild type cells (NHEK2), immortalized wild type cells (NEB1) and immortalized mutant cells (KEB7). The cortical stiffness was measured by lateral indentation of cells with AOD-steered optical tweezers without employing any moving mechanical elements. The method was validated on fixed cells and Cytochalasin-D treated cells to ensure that the observed variations in stiffness within a single cell line were not a consequence of low measurement precision. The measurements of the cortical stiffness showed that primary wild type cells were significantly stiffer than immortalized wild type cells, which was also detected in previous studies of bulk elasticity. In addition, a small difference between the mutant and the wild type cells was detected, showing that mutation of keratin impacts also the cell cortex. Thus, our results indicate that the role of keratins in cortical stiffness is not negligible and call for further investigation of the mechanical interactions between keratins and elements of the cell cortex.
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Feki F, Taktak R, Kandil K, Derrouiche A, Moulart M, Haddar N, Zaïri F, Zaïri F. How Osmoviscoelastic Coupling Affects Recovery of Cyclically Compressed Intervertebral Disc. Spine (Phila Pa 1976) 2020; 45:E1376-E1385. [PMID: 33031252 DOI: 10.1097/brs.0000000000003593] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Osmoviscoelastic behavior of cyclically loaded cervical intervertebral disc. OBJECTIVE The aim of this study was to evaluate in vitro the effects of physiologic compressive cyclic loading on the viscoelastic properties of cervical intervertebral disc and, examine how the osmoviscoelastic coupling affects time-dependent recovery of these properties following a long period of unloading. SUMMARY OF BACKGROUND DATA The human neck supports repetitive loadings during daily activities and recovery of disc mechanics is essential for normal mechanical function. However, the response of cervical intervertebral disc to cyclic loading is still not very well defined. Moreover, how loading history conditions could affect the time-dependent recovery is still unclear. METHODS Ten thousand cycles of compressive loading, with different magnitudes and saline concentrations of the surrounding fluid bath, are applied to 8 motion segments (composed by 2 adjacent vertebrae and the intervening disc) extracted from the cervical spines of mature sheep. Subsequently, specimens are hydrated during 18 hours of unloading. The viscoelastic disc responses, after cyclic loading and recovery phase, are characterized by relaxation tests. RESULTS Viscoelastic behaviors are significantly altered following large number of cyclic loads. Moreover, after 18-hour recovery period in saline solution at reference concentration (0.15 mol/L), relaxation behaviors were fully restored. Nonetheless, full recovery is not obtained whether the concentration of the surrounding fluid, that is, hypo-, iso-, or hyper-osmotic conditions. CONCLUSION Cyclic loading effects and full recovery of viscoelastic behavior after hydration at iso-osmotic condition (0.15 mol/L) are governed by osmotic attraction of fluid content in the disc due to imbalance between the external load and the swelling pressure of the disc. After removal of the load, the disc recovers its viscoelastic properties following period of rest. Nevertheless, the viscoelastic recovery is a chemically activated process and its dependency on saline concentration is governed by fluid flow due to imbalance of ions between the disc tissues and the surrounding fluid. LEVEL OF EVIDENCE 3.
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Kumari P, Pillai VVS, Rodriguez BJ, Prencipe M, Benedetto A. Sub-Toxic Concentrations of Ionic Liquids Enhance Cell Migration by Reducing the Elasticity of the Cellular Lipid Membrane. J Phys Chem Lett 2020; 11:7327-7333. [PMID: 32794718 DOI: 10.1021/acs.jpclett.0c02149] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Cell migration is a universal and crucial mechanism for life. It is required in a series of physiological processes, in wound repair and immune response and is involved in several pathological conditions, including cancer and virus dissemination. Among the several biochemical and biophysical routes, changing cell membrane elasticity holds the promise to be a universal strategy to alter cell mobility. Due to their affinity with cell membranes, ionic liquids (ILs) may play an important role. This work focuses on the effect of subtoxic amounts of imidazolium-ILs on the migration of the model cancer cell line MDA-MB-231. Here we show that ILs are able to enhance cell mobility by reducing the elasticity of the cellular lipid membrane, and that both mobility and elasticity can be tuned by IL-concentration and IL-cation chain length. This biochemical-physical mechanism is potentially valid for all mammalian cells, and its impact in bionanomedicine and bionanotechnology is discussed.
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Spaggiari G, Cignarelli A, Sansone A, Baldi M, Santi D. To beer or not to beer: A meta-analysis of the effects of beer consumption on cardiovascular health. PLoS One 2020; 15:e0233619. [PMID: 32492025 PMCID: PMC7269243 DOI: 10.1371/journal.pone.0233619] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 05/08/2020] [Indexed: 01/16/2023] Open
Abstract
A moderate alcohol consumption is demonstrated to exert a protective action in terms of cardiovascular risk. Although this property seems not to be beverage-specific, the various composition of alcoholic compounds could mediate peculiar effects in vivo. The aim of this study was to evaluate potential beer-mediated effects on the cardiovascular health in humans, using a meta-analytic approach (trial registration number: CRD42018118387). The literature search, comprising all English articles published until November, 30th 2019 in EMBASE, PubMed and Cochrane database included all controlled clinical trials evaluating the cardiovascular effects of beer assumption compared to alcohol-free beer, water, abstinence or placebo. Both sexes and all beer preparations were considered eligible. Outcome parameters were those entering in the cardiovascular risk charts and those related to endothelial dysfunction. Twenty-six trials were included in the analysis. Total cholesterol was significantly higher in beer drinkers compared to controls (14 studies, 3.52 mg/dL, 1.71–5.32 mg/dL). Similar increased levels were observed in high-density lipoprotein (HDL) cholesterol (18 studies, 3.63 mg/dL, 2.00–5.26 mg/dL) and in apolipoprotein A1 (5 studies, 0.16 mg/dL, 0.11–0.21 mg/dL), while no differences were detected in low density lipoprotein (LDL) cholesterol (12 studies, -2.85 mg/dL, -5.96–0.26 mg/dL) and triglycerides (14 studies, 0.40 mg/dL, -5.00–5.80 mg/dL) levels. Flow mediated dilation (FMD) resulted significantly higher in beer-consumers compared to controls (4 studies, 0.65%, 0.07–1.23%), while blood pressure and other biochemical markers of inflammation did not differ. In conclusion, the specific beer effect on human cardiovascular health was meta-analysed for the first time, highlighting an improvement of the vascular elasticity, detected by the increase of FMD (after acute intake), and of the lipid profile with a significant increase of HDL and apolipoprotein A1 serum levels. Although the long-term effects of beer consumption are not still understood, a beneficial effect of beer on endothelial function should be supposed.
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Sumi T, Yamamoto H, Hirano-Iwata A. Suppression of hypersynchronous network activity in cultured cortical neurons using an ultrasoft silicone scaffold. SOFT MATTER 2020; 16:3195-3202. [PMID: 32096811 DOI: 10.1039/c9sm02432h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The spontaneous activity pattern of cortical neurons in dissociated culture is characterized by burst firing that is highly synchronized among a wide population of cells. The degree of synchrony, however, is excessively higher than that in cortical tissues. Here, we employed polydimethylsiloxane (PDMS) elastomers to establish a novel system for culturing neurons on a scaffold with an elastic modulus resembling brain tissue, and investigated the effect of the scaffold's elasticity on network activity patterns in cultured rat cortical neurons. Using whole-cell patch clamp to assess the scaffold effect on the development of synaptic connections, we found that the amplitude of excitatory postsynaptic current, as well as the frequency of spontaneous transmissions, was reduced in neuronal networks grown on an ultrasoft PDMS with an elastic modulus of 0.5 kPa. Furthermore, the ultrasoft scaffold was found to suppress neural correlations in the spontaneous activity of the cultured neuronal network. The dose of GsMTx-4, an antagonist of stretch-activated cation channels (SACs), required to reduce the generation of the events below 1.0 event per min on PDMS substrates was lower than that for neurons on a glass substrate. This suggests that the difference in the baseline level of SAC activation is a molecular mechanism underlying the alteration in neuronal network activity depending on scaffold stiffness. Our results demonstrate the potential application of PDMS with biomimetic elasticity as cell-culture scaffold for bridging the in vivo-in vitro gap in neuronal systems.
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Tamayo L, Melo F, Caballero L, Hamm E, Díaz M, Leal MS, Guiliani N, Urzúa MD. Does Bacterial Elasticity Affect Adhesion to Polymer Fibers? ACS APPLIED MATERIALS & INTERFACES 2020; 12:14507-14517. [PMID: 32118396 DOI: 10.1021/acsami.9b21060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The factors governing bacterial adhesion to substrates with different topographies are still not fully identified. The present work seeks to elucidate for the first time and with quantitative data the roles of bacterial elasticity and shape and substrate topography in bacterial adhesion. With this aim, populations of three bacterial species, P. aeruginosa DSM 22644, B. subtilis DSM 10, and S. aureus DSM 20231 adhered on flat substrates covered with electrospun polycaprolactone fibers of different diameters ranging from 0.4 to 5.5 μm are counted. Populations of bacterial cells are classified according to the preferred binding sites of the bacteria to the substrate. The colloidal probe technique was used to assess the stiffness of the bacteria and bacteria-polymer surface adhesion energy. A theoretical model is developed to interpret the observed populations in terms of a balance between stiffness and adhesion energy of the bacteria. The model, which also incorporates the radius of the fiber and the size and shape of the bacteria, predicts increased adhesion for a low level of stiffness and for a larger number of available bacteria-fiber contact points. Te adhesive propensity of bacteria depends in a nontrivial way on the radius of the fibers due to the random arrangement of fibers.
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Haddad A, Menezes A, Guarnieri C, Coimbra D, Ribeiro E, Sarubi J, Avelar LE, Del Nero MP, da Cunha MG, Mazzuco R, Kamamoto C, Cazerta C. Recommendations on the Use of Injectable Poly-L-Lactic Acid for Skin Laxity in Off-Face Areas. J Drugs Dermatol 2019; 18:929-935. [PMID: 31524350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Injectable poly-L-lactic acid (PLLA) is a biodegradable synthetic polymer that stimulates collagen production, leading to gradual volume restoration. The treatment of sagging skin in body areas is still a big challenge, as there are few aesthetic procedures aiming to improve it. This article provides recommendations on the use of PLLA in the treatment of skin laxity in off-face areas, as the neck, décolletage, arms, abdomen, buttocks, and thighs, including the patient selection, product preparation, and injection techniques. The use of PLLA is a promising method for the treatment of skin laxity in corporal areas, improving body contour and appearance. Further investigation is needed to better understand the efficacy and durability of PLLA in non-facial indications and to provide the best evidence for optimal patient outcomes. J Drugs Dermatol. 2019;18(9):929-935.
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Cascione M, De Matteis V, Mandriota G, Leporatti S, Rinaldi R. Acute Cytotoxic Effects on Morphology and Mechanical Behavior in MCF-7 Induced by TiO 2NPs Exposure. Int J Mol Sci 2019; 20:ijms20143594. [PMID: 31340471 PMCID: PMC6678441 DOI: 10.3390/ijms20143594] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/15/2019] [Accepted: 07/19/2019] [Indexed: 12/23/2022] Open
Abstract
The side effects induced by nanoparticle exposure at a cellular level are one of the priority research topics due to the steady increase in the use of nanoparticles (NPs). Recently, the focus on cellular morphology and mechanical behavior is gaining relevance in order to fully understand the cytotoxic mechanisms. In this regard, we have evaluated the morphomechanical alteration in human breast adenocarcinoma cell line (MCF-7) exposed to TiO2NPs at two different concentrations (25 and 50 µg/mL) and two time points (24 and 48 h). By using confocal and atomic force microscopy, we demonstrated that TiO2NP exposure induces significant alterations in cellular membrane elasticity, due to actin proteins rearrangement in cytoskeleton, as calculated in correspondence to nuclear and cytoplasmic compartments. In this work, we have emphasized the alteration in mechanical properties of the cellular membrane, induced by nanoparticle exposure.
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Ito N, Seki S, Ueda F. Effects of Composite Supplement Containing Collagen Peptide and Ornithine on Skin Conditions and Plasma IGF-1 Levels-A Randomized, Double-Blind, Placebo-Controlled Trial. Mar Drugs 2018; 16:md16120482. [PMID: 30513923 PMCID: PMC6315531 DOI: 10.3390/md16120482] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 02/07/2023] Open
Abstract
Aging-associated changes of skin conditions are a major concern for maintaining quality of life. Therefore, the improvement of skin conditions by dietary supplementation is a topic of public interest. In this study, we hypothesized that a composite supplement containing fish derived-collagen peptide and ornithine (CPO) could improve skin conditions by increasing plasma growth hormone and/or insulin-like growth factor-1 (IGF-1) levels. Twenty-two healthy Japanese participants were enrolled in an 8-week double-blind placebo-controlled pilot study. They were assigned to either a CPO group, who were supplemented with a drink containing CPO, or an identical placebo group. We examined skin conditions including elasticity and transepidermal water loss (TEWL), as well as plasma growth hormone and IGF-1 levels. Skin elasticity and TEWL were significantly improved in the CPO group compared with the placebo group. Furthermore, only the CPO group showed increased plasma IGF-1 levels after 8 weeks of supplementation compared with the baseline. Our results might suggest the novel possibility for the use of CPO to improve skin conditions by increasing plasma IGF-1 levels.
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Liu Y, Dimango E, Bucovsky M, Agarwal S, Nishiyama K, Guo XE, Shane E, Stein EM. Abnormal microarchitecture and stiffness in postmenopausal women using chronic inhaled glucocorticoids. Osteoporos Int 2018; 29:2121-2127. [PMID: 29947865 PMCID: PMC6138454 DOI: 10.1007/s00198-018-4591-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/27/2018] [Indexed: 12/19/2022]
Abstract
UNLABELLED Postmenopausal (PM) women using inhaled glucocorticoids (IGCs) had substantial abnormalities in volumetric BMD (vBMD), microarchitecture, and stiffness using high resolution peripheral computed tomography (HRpQCT) compared to age- and race-matched controls. Abnormalities were most severe at the radius. These preliminary results suggest that there may be major, heretofore unrecognized, skeletal deficits in PM women using IGCs. INTRODUCTION While oral glucocorticoids are well recognized to have destructive skeletal effects, less is known about the effects of IGCs. The detrimental skeletal effects of IGCs may be greatest in PM women, in whom they compound negative effects of estrogen loss and aging. The goal of this study was to evaluate microarchitecture and stiffness in PM women using chronic IGCs. METHODS This case-control study compared PM women using IGCs for ≥ 6 months (n = 20) and controls matched for age and race/ethnicity (n = 60). Skeletal parameters assessed included areal BMD (aBMD) by DXA, trabecular and cortical vBMD and microarchitecture by HRpQCT of the radius and tibia, and whole bone stiffness by finite element analysis. RESULTS By DXA, mean values in both groups were in the osteopenic range; hip aBMD was lower in IGC users (P < 0.04). By HRpQCT, IGC users had lower total, cortical, and trabecular vBMD at both radius and tibia (all P < 0.05). IGC users had lower cortical thickness, lower trabecular number, greater trabecular separation and heterogeneity at the radius (all P < 0.03), and greater heterogeneity at the tibia (P < 0.04). Whole bone stiffness was lower in IGC users at radius (P < 0.03) and tended to be lower at the tibia (P = 0.09). CONCLUSIONS PM women using IGCs had substantial abnormalities in vBMD, microarchitecture, and stiffness compared to controls. These abnormalities were most severe at the radius. These preliminary results suggest that there may be major, heretofore unrecognized, skeletal deficits in PM women using IGCs.
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Bao F, Zheng Y, Liu C, Zheng X, Zhao Y, Wang Y, Li L, Wang Q, Chen S, Elsheikh A. Changes in Corneal Biomechanical Properties With Different Corneal Cross-linking Irradiances. J Refract Surg 2018; 34:51-58. [PMID: 29315442 DOI: 10.3928/1081597x-20171025-01] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 10/19/2017] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate whether different corneal cross-linking (CXL) irradiances, all with the same delivered total energy, achieve similar increases in corneal material stiffness. METHODS One hundred twenty-six healthy white Japanese rabbits were randomly divided into seven groups (n = 18 each). After removing the epithelium of the left corneas, six groups were exposed to riboflavin (0.22% concentration by volume) and ultraviolet-A (370 nm) at different CXL irradiations, all with the same total dose (5.4 J/cm2), ranging from 3 mW/cm2 for 30 minutes to 90 mW/cm2 for 1 minute. The left corneas of the seventh group were exposed to riboflavin without irradiation. Twelve corneas of each group were prepared for inflation testing, where they were subjected to internal hydrostatic pressure simulating intraocular pressure, whereas the other six specimens were processed for electron microscopy measurements of fibril diameter and interfibrillar spacing. The inverse modeling process was used to estimate the tangent modulus of the tissue, which is considered an accurate measure of the material stiffness. RESULTS The stiffening effect of CXL decreased when using high irradiation/short duration settings. Compared with the group with no irradiation (NUVA group), the tangent modulus increases reduced from 212.5% in the 3mW/30min group to 196.8% in the 90mW/1min group. These increases were significant (P < .05) in the 3mW/30min and 9mW/10min groups, but became insignificant in other CXL groups. The interfibrillar spacing in the anterior 50 μm of the corneal stroma also reduced with high irradiation/short duration settings, changing from 20.05 ± 1.89 nm in the NUVA group down to 13.06 ± 2.07 and 14.37 ± 1.90 nm in the 3mW/30min and 9mW/10min groups, respectively. These changes were significant (P < .05) between non-adjacent groups, but became non-significant otherwise. The corresponding changes in fibril diameter were small and nonsignificant in all cases (P > .05). CONCLUSIONS Because the effect of CXL in stiffening the tissue and reducing the interfibrillar spacing consistently decreased with reducing the irradiance duration, the Bunsen-Roscoe law may not be readily applicable in the CXL of corneal tissue. [J Refract Surg. 2018;34(1):51-58.].
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Mathelié-Guinlet M, Grauby-Heywang C, Martin A, Février H, Moroté F, Vilquin A, Béven L, Delville MH, Cohen-Bouhacina T. Detrimental impact of silica nanoparticles on the nanomechanical properties of Escherichia coli, studied by AFM. J Colloid Interface Sci 2018; 529:53-64. [PMID: 29883930 DOI: 10.1016/j.jcis.2018.05.098] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 05/24/2018] [Accepted: 05/27/2018] [Indexed: 12/17/2022]
Abstract
Despite great innovative and technological promises, nanoparticles (NPs) can ultimately exert an antibacterial activity by affecting the cell envelope integrity. This envelope, by conferring the cell its rigidity and protection, is intimately related to the mechanical behavior of the bacterial surface. Depending on their size, surface chemistry, shape, NPs can induce damages to the cell morphology and structure among others, and are therefore expected to alter the overall mechanical properties of bacteria. Although Atomic Force Microscopy (AFM) stands as a powerful tool to study biological systems, with high resolution and in near physiological environment, it has rarely been applied to investigate at the same time both morphological and mechanical degradations of bacteria upon NPs treatment. Consequently, this study aims at quantifying the impact of the silica NPs (SiO2-NPs) on the mechanical properties of E. coli cells after their exposure, and relating it to their toxic activity under a critical diameter. Cell elasticity was calculated by fitting the force curves with the Hertz model, and was correlated with the morphological study. SiO2-NPs of 100 nm diameter did not trigger any significant change in the Young modulus of E. coli, in agreement with the bacterial intact morphology and membrane structure. On the opposite, the 4 nm diameter SiO2-NPs did induce a significant decrease in E. coli Young modulus, mainly associated with the disorganization of lipopolysaccharides in the outer membrane and the permeation of the underlying peptidoglycan layer. The subsequent toxic behavior of these NPs is finally confirmed by the presence of membrane residues, due to cell lysis, exhibiting typical adhesion features.
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