scholarly journals Ultra-fast self-gelling powder mediate robust wet adhesion to promote healing of gastrointestinal perforations

2020 ◽  
Author(s):  
Xin Peng ◽  
Xianfeng Xia ◽  
Xiayi Xu ◽  
Xuefeng Yang ◽  
Boguang Yang ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Gastric Perforation ◽  
Interfacial Water ◽  
Wet Adhesion ◽  
Tissue Interactions ◽  
Strong Adhesion ◽  
Physical Interactions ◽  
Physically Crosslinked ◽  
Complex Target

Abstract Achieving strong adhesion of bioadhesives on wet tissues remains a challenge and an acute clinical need due to the interfering interfacial water and lack of adhesive–tissue interactions. Herein we report a self-gelling and adhesive polyethyleneimine and polyacrylic acid (PEI/PAA) powder, which can absorb interfacial water to rapidly form a physically crosslinked hydrogel in situ within two seconds due to strong physical interactions between the polymers. Furthermore, the physically crosslinked polymers can diffuse into the substrate polymeric network to enhance wet adhesion on various tissues. Superficial deposition of PEI/PAA powder can effectively seal damaged porcine stomach and intestine despite excessive mechanical challenges. We further demonstrate the use of PEI/PAA powder as sealants to enhance the treatment outcomes of gastric perforation in a rat model. Owing to their strong wet adhesion, excellent cytocompatibility, adaptability to fit complex target sites, and easy synthesis, we believe that the PEI/PAA powder are promising bioadhesives with a wide array of biomedical applications.

scholarly journals Ultrafast self-gelling powder mediates robust wet adhesion to promote healing of gastrointestinal perforations

2021 ◽  
Vol 7 (23) ◽  
pp. eabe8739
Author(s):  
Xin Peng ◽  
Xianfeng Xia ◽  
Xiayi Xu ◽  
Xuefeng Yang ◽  
Boguang Yang ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Gastric Perforation ◽  
Interfacial Water ◽  
Wet Adhesion ◽  
Tissue Interactions ◽  
Tissue Surface ◽  
Strong Adhesion ◽  
Surface Irregularities ◽  
Physical Interactions

Achieving strong adhesion of bioadhesives on wet tissues remains a challenge and an acute clinical demand because of the interfering interfacial water and limited adhesive-tissue interactions. Here we report a self-gelling and adhesive polyethyleneimine and polyacrylic acid (PEI/PAA) powder, which can absorb interfacial water to form a physically cross-linked hydrogel in situ within 2 seconds due to strong physical interactions between the polymers. Furthermore, the physically cross-linked polymers can diffuse into the substrate polymeric network to enhance wet adhesion. Superficial deposition of PEI/PAA powder can effectively seal damaged porcine stomach and intestine despite excessive mechanical challenges and tissue surface irregularities. We further demonstrate PEI/PAA powder as an effective sealant to enhance the treatment outcomes of gastric perforation in a rat model. The strong wet adhesion, excellent cytocompatibility, adaptability to fit complex sites, and easy synthesis of PEI/PAA powder make it a promising bioadhesive for numerous biomedical applications.

Anodic synthesis of TiO2 nanotubes by step-up voltages

2021 ◽  
pp. 002199832110237
Author(s):  
V Sivaprakash ◽  
R Narayanan
Keyword(s):  
Corrosion Resistance ◽  
Tio2 Nanotubes ◽  
Biomedical Applications ◽  
Phase Changes ◽  
Electrochemical Anodization ◽  
Corrosion Resistant ◽  
Anodization Process ◽  
Anodic Synthesis ◽  
Input Potential

Fabrication of TiO2 nanotubes (NTs) has extensive application properties due to their high corrosion resistant and compatibility with biomedical applications, the synthesis of TiO2 nanotubes over titanium has drawn interest in various fields. The synthesis of TiO2 NTs using novel in-situ step-up voltage conditions in the electrochemical anodization process is recorded in this work. For manufacturing the NTs at 1 hour of anodization, the input potential of 30, 40 and 50 V was selected. With increasing step-up voltage during the anodization process, an improvement in the NTs was observed, favoring corrosion resistance properties. The surface of NTs enhances the structure of the ribs, raising the potential for feedback over time. XRD was used to analyze phase changes, and HR-SEM analyzed surface topography. Impedance tests found that longer NTs improved the corrosion resistance.

CLINICAL APPLICATIONS OF ELECTROCHEMOTHERAPY

2019 ◽  
Author(s):  
Gregor Serša
Keyword(s):  
Biomedical Applications ◽  
Liver Tumors ◽  
Checkpoint Inhibitors ◽  
Combined Treatment ◽  
Local Treatment ◽  
Industrial Applications ◽  
Interleukin 12 ◽  
Nice Guidelines ◽  
Or Gene

Electroporation has several biomedical and industrial applications. The biomedical applications are in the field of drug or gene delivery. Electrochemotherapy utilizes electroporation for the increased delivery of cytotoxic drugs like bleomycin or cisplatin into tumors. The use of electrochemotherapy has spread throughout Europe for the treatment of cutaneous tumors or metastases. It is in the NICE guidelines and is becoming standard ablative technique in treatment of cancer. The technological advancements have also enabled the use of electrochemotherapy for the treatment of deep seated tumors, such as soft tissue or liver tumors. Clinical studies demonstrate good effectiveness on fibrosarcomas, colorectal liver metastases and hepatocellular carcinoma. However, electrochemotherapy is a local treatment that also induces moderate local immune response. This so called “in situ vaccination” induced by electrochemotherapy can be exploited in combined treatment with immune checkpoint inhibitors or electrogene therapy with immunostimulating effect. Therefore, gene electrotransfer of plasmid coding for interleukin 12 (IL-12), in combination with electrochemotherapy could result in transformation of electrochemotherapy from local into systemic treatment. This is also of our current interest, and we are undertaking steps to bring this idea from preclinical into clinical testing.

3-D and electrically conducting functional skin mapping for biomedical applications

2018 ◽  
Vol 54 (8) ◽  
pp. 980-983 ◽  
Author(s):  
Xiaoxu Fu ◽  
Wenqiu Zeng ◽  
Ana C. Ramírez-Pérez ◽  
Grzegorz Lisak
Keyword(s):  
Conducting Polymer ◽  
Biomedical Applications ◽  
Human Subject ◽  
Ex Situ ◽  
Electrically Conducting

Ex situ and in situ 3-D and electrically conducting mapping of the skin topography via electropolymerization of a conducting polymer on a previously sampled skin stamp or directly on the skin of a live human subject were performed here with the intention to be further used in biomedical applications.

An antibacterial biomimetic adhesive with strong adhesion in both dry and underwater situations

2022 ◽  
Author(s):  
Lin Li ◽  
Haitao Peng ◽  
Yan Du ◽  
Heng Zheng ◽  
Aiping Yang ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Antibacterial Properties ◽  
Strong Adhesion

Adhesives have been attracting extensive attention in biomedical applications in recent years. However, developing an adhesive with strong adhesion in both dry and underwater situations as well as antibacterial properties...

Biodegradable poly(propylene) carbonate using in-situ generated CuNPs coated Tamarindus indica filler for biomedical applications

2019 ◽  
Vol 19 ◽  
pp. 106-113 ◽  
Author(s):  
M.P. Indira Devi ◽  
N. Nallamuthu ◽  
N. Rajini ◽  
T. Senthil Muthu Kumar ◽  
Suchart Siengchin ◽  
...  
Keyword(s):  
Propylene Carbonate ◽  
Biomedical Applications ◽  
Tamarindus Indica ◽  
Biodegradable Poly ◽  
Poly Propylene

scholarly journals Fabrication and Characterization of Zein/Hydroxyapatite Composite Coatings for Biomedical Applications

Surfaces ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 237-250 ◽  
Author(s):  
Yusra Ahmed ◽  
Muhammad Yasir ◽  
Muhammad Atiq Ur Rehman
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Biomedical Applications ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Sem Images ◽  
Taguchi Design Of Experiments ◽  
Hydrophilic Nature ◽  
Strong Adhesion ◽  
Steel Substrates

Stainless steel is renowned for its wide use as a biomaterial, but its relatively high corrosion rate in physiological environments restricts many of its clinical applications. To overcome the corrosion resistance of stainless steel bio-implants in physiological environments and to improve its osseointegration behavior, we have developed a unique zein/hydroxyapatite (HA) composite coating on a stainless steel substrate by Electrophoretic Deposition (EPD). The EPD parameters were optimized using the Taguchi Design of experiments (DoE) approach. The EPD parameters, such as the concentration of bio-ceramic particles in the polymer solution, applied voltage and deposition time were optimized on stainless steel substrates by applying a mixed design orthogonal Taguchi array. The coatings were characterized by using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and wettability studies. SEM images and EDX results indicated that the zein/HA coating was successfully deposited onto the stainless steel substrates. The wettability and roughness studies elucidated the mildly hydrophilic nature of the zein/HA coatings, which confirmed the suitability of the developed coatings for biomedical applications. Zein/HA coatings improved the corrosion resistance of bare 316L stainless steel. Moreover, zein/HA coatings showed strong adhesion with the 316L SS substrate for biomedical applications. Zein/HA developed dense HA crystals upon immersion in simulated body fluid, which confirmed the bone binding ability of the coatings. Thus the zein/HA coatings presented in this study have a strong potential to be considered for orthopedic applications.

scholarly journals Amphipathic Substrates Based on Crosslinker-Free Poly(ε-Caprolactone):Poly(2-Hydroxyethyl Methacrylate) Semi-Interpenetrated Networks Promote Serum Protein Adsorption

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1256
Author(s):  
Guillermo Vilariño-Feltrer ◽  
Alfredo Salgado-Gallegos ◽  
Joan de-la-Concepción-Ausina ◽  
José Carlos Rodríguez-Hernández ◽  
Mohsen Shahrousvand ◽  
...  
Keyword(s):  
Serum Protein ◽  
Biomedical Applications ◽  
Simple Procedure ◽  
Solution Polymerization ◽  
Hydroxyethyl Methacrylate ◽  
Polymer Substrates ◽  
Step Procedure ◽  
Physically Crosslinked ◽  
Hydroxyl Hydrogen ◽  
Polymer Fraction

A simple procedure has been developed to synthesize uncrosslinked soluble poly(hydroxyethyl methacrylate) (PHEMA) gels, ready for use in a subsequent fabrication stage. The presence of 75 wt % methanol (MetOH) or dimethylformamide (DMF) impedes lateral hydroxyl–hydroxyl hydrogen bonds between PHEMA macromers to form during their solution polymerization at 60 °C, up to 24 h. These gels remain soluble when properly stored in closed containers under cold conditions and, when needed, yield by solvent evaporation spontaneous physically-crosslinked PHEMA adapted to the mould used. Moreover, this two-step procedure allows obtaining multicomponent systems where a stable and water-affine PHEMA network would be of interest. In particular, amphiphilic polycaprolactone (PCL):PHEMA semi-interpenetrated (sIPN) substrates have been developed, from quaternary metastable solutions in chloroform (CHCl3):MetOH 3:1 wt. and PCL ranging from 50 to 90 wt % in the polymer fraction (thus determining the composition of the solution). The coexistence of these countered molecules, uniformly distributed at the nanoscale, has proven to enhance the number and interactions of serum protein adsorbed from the acellular medium as compared to the homopolymers, the sIPN containing 80 wt % PCL showing an outstanding development. In accordance to the quaternary diagram presented, this protocol can be adapted for the development of polymer substrates, coatings or scaffolds for biomedical applications, not relying upon phase separation, such as the electrospun mats here proposed herein (12 wt % polymer solutions were used for this purpose, with PCL ranging from 50% to 100% in the polymer fraction).

A new emulsification-crosslinking technique for preparation of physically crosslinked chitosan microspheres

2020 ◽  
Vol 35 (4-5) ◽  
pp. 289-300
Author(s):  
Aiping Shi ◽  
Ying Guan ◽  
Yongjun Zhang
Keyword(s):  
Acetic Acid ◽  
Chitosan Solution ◽  
Curing Temperature ◽  
Urea Solution ◽  
Chitosan Microspheres ◽  
Model Protein ◽  
Crosslinked Chitosan ◽  
Physically Crosslinked ◽  
Emulsifier Concentration

A new emulsification-crosslinking method was developed for the preparation of chitosan microspheres. The new method uses an aqueous alkali–urea solution, instead of the commonly used acidic solvents, to dissolve chitosan. After emulsification, the water-in-oil droplets are solidified by heating, taking advantage of the unique in situ thermal gelling behavior of the alkaline chitosan solution, instead of by crosslinking with a usually toxic crosslinker. The size of the microspheres can be controlled by the concentration of chitosan solution, stirring speed, emulsifier concentration, and the curing temperature. The resulting microspheres are physically crosslinked, instead of chemically crosslinked, and they are ready to dissolve in dilute acetic acid. The resulting chitosan microspheres are non-toxic and can be degraded by lysozyme. Bovine serum albumin, a model protein, can be facilely loaded into the microspheres by adsorption, and then released from the microspheres.

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