scholarly journals Influence of Biocompatible Coating on Titanium Surface Characteristics

2020 ◽  
Author(s):  
Željka Petrović ◽  
Jozefina Katić ◽  
Ankica Šarić ◽  
Ines Despotović ◽  
Nives Matijaković ◽  
...  
Keyword(s):  
Self Assembly ◽  
Titanium Surface ◽  
Electrochemical Impedance ◽  
Calcium Phosphates ◽  
Artificial Saliva ◽  
Surface Characteristics ◽  
Corrosion Stability ◽  
Assembly Method

Background: Nowadays investigations in the field of dental implants engineering are focused on bioactivity and osseointegration properties.Objective: In this study, the oxide-covered titanium was functionalized by vitamin D3 molecules via a simple self-assembly method with the aim to design more corrosion resistant and at the same time more bioactive surface.Methods: Surface properties of the D3-coated titanium were examined by scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and contact angle measurements, while a long-term corrosion stability during immersion in an artificial saliva solution was investigated in situ by electrochemical impedance spectroscopy.Results: Results of all techniques confirmed a successful formation of the D3 vitamin layer on the oxide-covered titanium. Besides very good corrosion resistivity (~5 MΩcm2 ) the D3-modified titanium surface induced spontaneous formation of biocompatible bone-like calcium phosphates (CaP).Conclusion: Observed in vitro CaP-forming ability as a result of D3-modified titanium/artificial saliva interactions could serve as a promising predictor of in vivo bioactivity of implant materials.

scholarly journals Influence of Biocompatible Coating on Titanium Surface Characteristics

2020 ◽  
Vol 10 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Željka Petrović ◽  
Jozefina Katić ◽  
Ankica Šarić ◽  
Ines Despotović ◽  
Nives Matijaković ◽  
...  
Keyword(s):  
Vitamin D3 ◽  
Titanium Surface ◽  
Electrochemical Impedance ◽  
Calcium Phosphates ◽  
Artificial Saliva ◽  
Surface Characteristics ◽  
Corrosion Stability ◽  
Assembly Method

Background: Nowadays investigations in the field of dental implants engineering are focused on bioactivity and osseointegration properties. Objective: In this study, the oxide-covered titanium was functionalized by vitamin D3 molecules via a simple self-assembly method with the aim to design more corrosion-resistant and at the same time more bioactive surface. Methods: Surface properties of the D3-coated titanium were examined by scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and contact angle measurements, while long-term corrosion stability during immersion in an artificial saliva solution was investigated in situ by electrochemical impedance spectroscopy. Results: Results of all techniques confirmed a successful formation of the vitamin D3 layer on the oxide-covered titanium. Besides very good corrosion resistivity (~5 MΩ cm2), the D3-modified titanium surface induced spontaneous formation of biocompatible bone-like calcium phosphates (CaP). Conclusion: Observed in vitro CaP-forming ability as a result of D3-modified titanium/artificial saliva interactions could serve as a promising predictor of in vivo bioactivity of implant materials.

scholarly journals Human Organ-Specific 3D Cancer Models Produced by the Stromal Self-Assembly Method of Tissue Engineering for the Study of Solid Tumors

2020 ◽  
Vol 2020 ◽  
pp. 1-23 ◽  
Author(s):  
Vincent Roy ◽  
Brice Magne ◽  
Maude Vaillancourt-Audet ◽  
Mathieu Blais ◽  
Stéphane Chabaud ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Tumor Microenvironment ◽  
Self Assembly ◽  
The Self ◽  
Human Organ ◽  
Assembly Method ◽  
Cancer Models ◽  
Organ Specific

Cancer research has considerably progressed with the improvement of in vitro study models, helping to understand the key role of the tumor microenvironment in cancer development and progression. Over the last few years, complex 3D human cell culture systems have gained much popularity over in vivo models, as they accurately mimic the tumor microenvironment and allow high-throughput drug screening. Of particular interest, in vitrohuman 3D tissue constructs, produced by the self-assembly method of tissue engineering, have been successfully used to model the tumor microenvironment and now represent a very promising approach to further develop diverse cancer models. In this review, we describe the importance of the tumor microenvironment and present the existing in vitro cancer models generated through the self-assembly method of tissue engineering. Lastly, we highlight the relevance of this approach to mimic various and complex tumors, including basal cell carcinoma, cutaneous neurofibroma, skin melanoma, bladder cancer, and uveal melanoma.

scholarly journals Self-Assembly Iron Oxide Nanoclusters for Photothermal-Mediated Synergistic Chemo/Chemodynamic Therapy

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xiang Li ◽  
Zhen Wang ◽  
Mian Ma ◽  
Zhouqing Chen ◽  
Xiang-long Tang ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Self Assembly ◽  
Near Infrared ◽  
Light Irradiation ◽  
Infrared Light ◽  
Photothermal Effect ◽  
Photothermal Conversion ◽  
Assembly Method

Background and Purpose. Although chemodynamic therapy (CDT) is promising for cancer treatment, its clinical application is still limited because of unresolved issues. In this study, an efficient CDT agent for synergistic chemo/CDT therapy mediated by the photothermal effect was developed by an iron oxide self-assembly method. Methods. Superparamagnetic iron oxide nanoclusters (SPIOCs) were located within the core, which resulted in high photothermal conversion and outstanding generation of reactive oxygen species (ROS). The shell consisted of a human serum albumin- (HSA-) paclitaxel (PTX) layer, which extended the blood circulation time and ensured the effectiveness of the chemotherapy. Arg-Gly-Asp peptides (RGD) were linked to the naked cysteine moieties in HSA to promote the specific targeting of human glioma U87 cells by αvβ3 integrins. Continuous near-infrared light irradiation triggered and promoted the synergistic chemo/CDT therapy through the photothermal effect. Results. Our SPIOCs@HSA-RGD nanoplatform showed well biocompatibility and could target glioma specifically. Photothermal conversion and ROS burst were detected after continuous 808 nm light irradiation, and a significant antitumor effect was achieved. Conclusion. Experimental in vitro and in vivo evaluations showed that our photothermal-mediated chemo/CDT therapy could efficiently inhibit tumor growth and is therefore promising for cancer therapy.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Programmable in vitro Co-Encapsidation of Guest Proteins Inside Protein Nanocages

2018 ◽  
Author(s):  
Noor H. Dashti ◽  
Rufika S. Abidin ◽  
Frank Sainsbury
Keyword(s):  
Self Assembly ◽  
Mammalian Cells ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Super Resolution ◽  
Cell Engineering ◽  
Particle Analysis ◽  
Protein Cages

Bioinspired self-sorting and self-assembling systems using engineered versions of natural protein cages have been developed for biocatalysis and therapeutic delivery. The packaging and intracellular delivery of guest proteins is of particular interest for both <i>in vitro</i> and <i>in vivo</i> cell engineering. However, there is a lack of platforms in bionanotechnology that combine programmable guest protein encapsidation with efficient intracellular uptake. We report a minimal peptide anchor for <i>in vivo</i> self-sorting of cargo-linked capsomeres of the Murine polyomavirus (MPyV) major coat protein that enables controlled encapsidation of guest proteins by <i>in vitro</i> self-assembly. Using Förster resonance energy transfer (FRET) we demonstrate the flexibility in this system to support co-encapsidation of multiple proteins. Complementing these ensemble measurements with single particle analysis by super-resolution microscopy shows that the stochastic nature of co-encapsidation is an overriding principle. This has implications for the design and deployment of both native and engineered self-sorting encapsulation systems and for the assembly of infectious virions. Taking advantage of the encoded affinity for sialic acids ubiquitously displayed on the surface of mammalian cells, we demonstrate the ability of self-assembled MPyV virus-like particles to mediate efficient delivery of guest proteins to the cytosol of primary human cells. This platform for programmable co-encapsidation and efficient cytosolic delivery of complementary biomolecules therefore has enormous potential in cell engineering.

scholarly journals Development of In Situ Self-Assembly Nanoparticles to Encapsulate Lopinavir and Ritonavir for Long-Acting Subcutaneous Injection

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 904
Author(s):  
Irin Tanaudommongkon ◽  
Asama Tanaudommongkon ◽  
Xiaowei Dong
Keyword(s):  
Sustained Release ◽  
Trough Concentration ◽  
Self Assembly ◽  
Subcutaneous Injection ◽  
Drug Loading ◽  
Entrapment Efficiency ◽  
Long Acting

Most antiretroviral medications for human immunodeficiency virus treatment and prevention require high levels of patient adherence, such that medications need to be administered daily without missing doses. Here, a long-acting subcutaneous injection of lopinavir (LPV) in combination with ritonavir (RTV) using in situ self-assembly nanoparticles (ISNPs) was developed to potentially overcome adherence barriers. The ISNP approach can improve the pharmacokinetic profiles of the drugs. The ISNPs were characterized in terms of particle size, drug entrapment efficiency, drug loading, in vitro release study, and in vivo pharmacokinetic study. LPV/RTV ISNPs were 167.8 nm in size, with a polydispersity index of less than 0.35. The entrapment efficiency was over 98% for both LPV and RTV, with drug loadings of 25% LPV and 6.3% RTV. A slow release rate of LPV was observed at about 20% on day 5, followed by a sustained release beyond 14 days. RTV released faster than LPV in the first 5 days and slower than LPV thereafter. LPV trough concentration remained above 160 ng/mL and RTV trough concentration was above 50 ng/mL after 6 days with one subcutaneous injection. Overall, the ISNP-based LPV/RTV injection showed sustained release profiles in both in vitro and in vivo studies.

scholarly journals Wafer-Scale Fabrication and Assembly Method of Multichannel Microelectrode Arrays for ECoG Application

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 316
Author(s):  
Cong Wang ◽  
Yu-Chen Wei ◽  
Ho-Kun Sung ◽  
Alok Kumar ◽  
Zhong-Liang Zhou ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Electrochemical Impedance ◽  
Microelectrode Arrays ◽  
Absence Seizure ◽  
Curing Conditions ◽  
Wafer Scale ◽  
In Vivo Test ◽  
Assembly Method ◽  
Signal Recording

High density electrocorticography (ECoG)-based microelectrode arrays (MEAs) are fabricated to timely record the neural activities to provide the fundamental understanding in neuroscience and biomedical engineering. This paper aims to introduce a device-based concept and wafer-scale fabrication process for MEAs. Flexible and biocompatible polyimide is applied on MEAs to bear all possible stress and strain. Detailed fabrication key techniques, including surface treatment, polyimide stability measurement, evaporation process, and curing conditions, have been discussed thoroughly. Moreover, the fabricated polyimide-based MEAs are surface-mounted on well-packaged printed circuit boards (PCBs) via a slot-type connector without any additional wire bonding to make the signal recording process easier. An absence seizure was recorded during the in vivo test, which shows the availability of signal recording based on the presented MEAs. The proposed MEAs could be remained at the skull, while the connector and PCBs can be disassembled apart. Therefore, the testing sample will get less suffering. To verify the robustness of the fabricated MEAs, the impedance properties were characterized using electrochemical impedance spectroscopy. The measured results indicate an average impedance of 12.3 ± 0.675 kΩ at 1 kHz. In total, 10 groups of MEAs were sample tested, and over 90% of the total 60 channels per 1-MEAs operated efficiently.

scholarly journals Micro/nano-textured hierarchical titanium topography promotes exosome biogenesis and secretion to improve osseointegration

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Zhengchuan Zhang ◽  
Ruogu Xu ◽  
Yang Yang ◽  
Chaoan Liang ◽  
Xiaolin Yu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Titanium Surface ◽  
Titanium Implants ◽  
Extracellular Secretion ◽  
Exosome Biogenesis ◽  
Marrow Mesenchymal Stem Cells ◽  
Proliferation In Vitro ◽  
Extracellular Environment

Abstract Background Micro/nano-textured hierarchical titanium topography is more bioactive and biomimetic than smooth, micro-textured or nano-textured titanium topographies. Bone marrow mesenchymal stem cells (BMSCs) and exosomes derived from BMSCs play important roles in the osseointegration of titanium implants, but the effects and mechanisms of titanium topography on BMSCs-derived exosome secretion are still unclear. This study determined whether the secretion behavior of exosomes derived from BMSCs is differently affected by different titanium topographies both in vitro and in vivo. Results We found that both micro/nanonet-textured hierarchical titanium topography and micro/nanotube-textured hierarchical titanium topography showed favorable roughness and hydrophilicity. These two micro/nano-textured hierarchical titanium topographies enhanced the spreading areas of BMSCs on the titanium surface with stronger promotion of BMSCs proliferation in vitro. Compared to micro-textured titanium topography, micro/nano-textured hierarchical titanium topography significantly enhanced osseointegration in vivo and promoted BMSCs to synthesize and transport exosomes and then release these exosomes into the extracellular environment both in vitro and in vivo. Moreover, micro/nanonet-textured hierarchical titanium topography promoted exosome secretion by upregulating RAB27B and SMPD3 gene expression and micro/nanotube-textured hierarchical titanium topography promoted exosome secretion due to the strongest enhancement in cell proliferation. Conclusions These findings provide evidence that micro/nano-textured hierarchical titanium topography promotes exosome biogenesis and extracellular secretion for enhanced osseointegration. Our findings also highlight that the optimized titanium topography can increase exosome secretion from BMSCs, which may promote osseointegration of titanium implants.

scholarly journals Force generation by protein–DNA co-condensation

2021 ◽  
Author(s):  
Thomas Quail ◽  
Stefan Golfier ◽  
Maria Elsner ◽  
Keisuke Ishihara ◽  
Vasanthanarayan Murugesan ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Self Assembly ◽  
Spider Silk ◽  
Regulatory Elements ◽  
Heterochromatin Formation ◽  
First Order Phase Transition ◽  
Dna Strand ◽  
First Order Phase

AbstractInteractions between liquids and surfaces generate forces1,2 that are crucial for many processes in biology, physics and engineering, including the motion of insects on the surface of water3, modulation of the material properties of spider silk4 and self-assembly of microstructures5. Recent studies have shown that cells assemble biomolecular condensates via phase separation6. In the nucleus, these condensates are thought to drive transcription7, heterochromatin formation8, nucleolus assembly9 and DNA repair10. Here we show that the interaction between liquid-like condensates and DNA generates forces that might play a role in bringing distant regulatory elements of DNA together, a key step in transcriptional regulation. We combine quantitative microscopy, in vitro reconstitution, optical tweezers and theory to show that the transcription factor FoxA1 mediates the condensation of a protein–DNA phase via a mesoscopic first-order phase transition. After nucleation, co-condensation forces drive growth of this phase by pulling non-condensed DNA. Altering the tension on the DNA strand enlarges or dissolves the condensates, revealing their mechanosensitive nature. These findings show that DNA condensation mediated by transcription factors could bring distant regions of DNA into close proximity, suggesting that this physical mechanism is a possible general regulatory principle for chromatin organization that may be relevant in vivo.

Enhanced Entrapment and Improved in Vitro Controlled Release of N-Acetyl Cysteine in Hybrid PLGA/Lecithin Nanoparticles Prepared Using a Nanoprecipitation/Self-Assembly Method

2017 ◽  
Vol 118 (12) ◽  
pp. 4203-4209 ◽  
Author(s):  
Parvin Ahmaditabar ◽  
Amir A. Momtazi-Borojeni ◽  
Ali H. Rezayan ◽  
Mahboobeh Mahmoodi ◽  
Amirhossein Sahebkar ◽  
...  
Keyword(s):  
Controlled Release ◽  
Self Assembly ◽  
Assembly Method ◽  
Acetyl Cysteine
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