scholarly journals Sundew-Inspired Adhesive Hydrogel Threads through Reversible Complexation of Polyphenol and Boronic Acid

2021 ◽  
Vol 11 (18) ◽  
pp. 8591
Author(s):  
Jae Hyuk Choi ◽  
Donghee Son ◽  
Mikyung Shin

Adhesive hydrogels have been utilized as tissue sealants, hemostatic agents, and wound dressings, with the aim of replacing conventional sutures. To prevent immune response and serious inflammation from those hydrogels after sealing, natural biocompatible polysaccharides are widely used as a component of the hydrogels. However, the weak mechanical strength, insufficient adhesiveness, and rapid dissociation of the hydrogels necessitates additional suturing at the wound site. In this study, we report on a solid polysaccharide thread reversibly crosslinked with boronic acid-polyphenol complexation and its adhesive gelation for complete tissue sealing without additional suturing. The polysaccharide adhesive suture threads demonstrated long-term stability, which is useful when used for skin wound suturing. Specifically, their robust adhesion property occurred as soon as the threads were soaked, attaining a swollen hydrogel state, dependent on the presence of body fluids after suturing. Moreover, the pH of the body fluids affects the viscoelasticity and adhesiveness of the hydrogels in order to ensure a tight sealing. Therefore, we expect that these pH-responsive adhesive threads would be promising for the development of on-demand functional suture materials.

2007 ◽  
Vol 361-363 ◽  
pp. 311-314 ◽  
Author(s):  
Liam M. Grover ◽  
Sarika Patel ◽  
Y. Hu ◽  
Uwe Gbureck ◽  
J.E. Barralet

The hydrolysis of brushite in calcium phosphate cements to form hydroxyapatite is known to result in the long term stability of the material in the body. It has previously been established that this hydrolysis reaction can be influenced by implant volume, media refreshment rate and media composition. In this study, the effect of macroporosity on the rate of degradation of the material is investigated. Macroporosity was incorporated into the material using calcium alginate beads mixed into the cement paste. The inclusion of the calcium alginate beads did not influence the degree of conversion of the material and allowed the incorporation of porosity at up to maximum of 57%. The macroporosity weakened the cement matrix (from 46.5 to 3.2 MPa). When aged the brushite in the macroporous cement dissolved completely from the matrix resulting in a weight loss of 60wt% in a period of 28 days. This suggests that the controlled incorporation of calcium alginate beads into brushite cements in vivo can be used to control implant degradation rate.


2021 ◽  
Vol 21 (6) ◽  
pp. 227-237
Author(s):  
Seok-Ju Kim ◽  
Do-Kyun Kim

In soil dams and embankments made of soil, deterioration and stress release owing to internal and external influences occur, and the instability of the body increases as the shear strength decreases. In particular, understanding the location and flow of underground water is very important for securing the long-term stability of waterfront structures in contact with water. However, the physical limitations of measuring equipment cause many difficulties in understanding the existence and location of groundwater over a long period of time. In this study, measuring equipment using electric capacity was developed for the long-term measurement of groundwater, and contactless measuring sensors were manufactured to eliminate the possibility of corrosion by water. In addition, the precision of the measurement data was improved by applying waterproof and water-repellent coatings to the measurement sensor. Laboratory tests conducted using the developed equipment demonstrate the high precision of the measurement data according to the groundwater level change and enhanced durability of the sensor, which facilitate long-term measurements in the field.


2020 ◽  
Vol 2 (2) ◽  
pp. 32
Author(s):  
Iyan Sopyan ◽  
Dolih Gozali ◽  
Eka Paramudya

The use of drugs that are less soluble in water will become clinically less efficient, this is caused by the low penetration of the drug into the body. A microemulsion is a dispersion system such as an emulsion that can increase the solubility of drugs that are sometimes difficult to dissolve in water. Microemulsions have long-term stability, clear, transparent, and good penetration capabilities. In this study, a microemulsion formulation with active ingredients griseofulvin and virgin coconut oil was conducted as an oil phase. The resulting microemulsion evaluates physical stability during 35 storage days. The results showed that the microemulsion preparation remained stable during storage time without changes in color, odor, and consistency, while the pH and dosage viscosity experienced less significant changes. The consequences of the centrifugation test at 3700 rpm for 5 hours and freezing tests for 24 days showed stable preparation and cannot be separated. The diffusion test results obtained by FG2 had the largest permeation percentages of 3.6136%, FG3 2.8724%, and the smallest FG1 2.0477%.Keywords: microemulsion, griseofulvin, stability, diffusion test


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yong Suk Oh ◽  
Jae-Hwan Kim ◽  
Zhaoqian Xie ◽  
Seokjoo Cho ◽  
Hyeonseok Han ◽  
...  

AbstractCapabilities for continuous monitoring of pressures and temperatures at critical skin interfaces can help to guide care strategies that minimize the potential for pressure injuries in hospitalized patients or in individuals confined to the bed. This paper introduces a soft, skin-mountable class of sensor system for this purpose. The design includes a pressure-responsive element based on membrane deflection and a battery-free, wireless mode of operation capable of multi-site measurements at strategic locations across the body. Such devices yield continuous, simultaneous readings of pressure and temperature in a sequential readout scheme from a pair of primary antennas mounted under the bedding and connected to a wireless reader and a multiplexer located at the bedside. Experimental evaluation of the sensor and the complete system includes benchtop measurements and numerical simulations of the key features. Clinical trials involving two hemiplegic patients and a tetraplegic patient demonstrate the feasibility, functionality and long-term stability of this technology in operating hospital settings.


2005 ◽  
Vol 26 (2) ◽  
pp. 100-106 ◽  
Author(s):  
James D.A. Parker ◽  
Donald H. Saklofske ◽  
Laura M. Wood ◽  
Jennifer M. Eastabrook ◽  
Robyn N. Taylor

Abstract. The concept of emotional intelligence (EI) has attracted growing interest from researchers working in various fields. The present study examined the long-term stability (32 months) of EI-related abilities over the course of a major life transition (the transition from high school to university). During the first week of full-time study, a large group of undergraduates completed the EQ-i:Short; 32 months later a random subset of these students (N = 238), who had started their postsecondary education within 24 months of graduating from high school, completed the measures for a second time. The study found EI scores to be relatively stable over the 32-month time period. EI scores were also found to be significantly higher at Time 2; the overall pattern of change in EI-levels was more than can be attributed to the increased age of the participants.


1997 ◽  
Vol 2 (4) ◽  
pp. 293-300 ◽  
Author(s):  
Ype H. Poortinga ◽  
Ingrid Lunt

In national codes of ethics the practice of psychology is presented as rooted in scientific knowledge, professional skills, and experience. However, it is not self-evident that the body of scientific knowledge in psychology provides an adequate basis for current professional practice. Professional training and experience are seen as necessary for the application of psychological knowledge, but they appear insufficient to defend the soundness of one's practices when challenged in judicial proceedings of a kind that may be faced by psychologists in the European Union in the not too distant future. In seeking to define the basis for the professional competence of psychologists, this article recommends taking a position of modesty concerning the scope and effectiveness of psychological interventions. In many circumstances, psychologists can only provide partial advice, narrowing down the range of possible courses of action more by eliminating unpromising ones than by pointing out the most correct or most favorable one. By emphasizing rigorous evaluation, the profession should gain in accountability and, in the long term, in respectability.


1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.


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