Roles of chemistry modification for laser textured metal alloys to achieve extreme surface wetting behaviors

Superhydrophobic surfaces for broad applications in biological and biomedical sciences are good potential candidates for technological unsolved challenges. Using superhydrophobicity can supply a suitable and biocompatible strategy for making clean antibacterial surfaces, sensitive biosensors, significant methods for biocrystallization, tunable cell/platelet/blood adhesion surfaces, appropriate templates for gene/drug delivery and 3D cell engineering. Trapped air in surface roughness, surface convection and localizer effects, reduction in tissue-implant unwanted interactions and genes delivery pathways are some of the characteristics that superhydrophobic surfaces can provide to solve biological and biomedical technical restrictions. In this review, the mechanism and procedures of superhydrophobic surfaces and their impacts on biosystems have been studied and highlighted.

Superhydrophobicity: advanced biological and biomedical applications.

Wettability Transition for Laser Textured Surfaces: A Comprehensive Review

Titanium and its alloys have superb biocompatibility, low elastic modulus, and favorable corrosion resistance. These exceptional properties lead to its wide use as a medical implant material. Titanium itself does not have antibacterial properties, so bacteria can gather and adhere to its surface resulting in infection issues. The infection is among the main reasons for implant failure in orthopedic surgeries. Nano-modification, as one of the good options, has the potential to induce different degrees of antibacterial effect on the surface of implant materials. At the same time, the nano-modification procedure and the produced nanostructures should not adversely affect the osteogenic activity, and it should simultaneously lead to favorable antibacterial properties on the surface of the implant. This article scrutinizes and deals with the surface nano-modification of titanium implant materials from three aspects: nanostructures formation procedures, nanomaterials loading, and nano-morphology. In this regard, the research progress on the antibacterial properties of various surface nano-modification of titanium implant materials and the related procedures are introduced, and the new trends will be discussed in order to improve the related materials and methods.

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Nano-Modified Titanium Implant Materials: A Way Toward Improved Antibacterial Properties.

Polymicrobial infections are one of the most common reasons for inflammation of surrounding tissues and failure of implanted biomaterials. Because microorganism adhesion is the first step for biofilm formation, physical-chemical modifications of biomaterials have been proposed to reduce the initial microbial attachment. Thus, the use of superhydrophobic coatings has emerged because of their anti-biofilm properties. However, these coatings on the titanium (Ti) surface have been developed mainly by dual-step surface modification techniques and have not been tested using polymicrobial biofilms. Therefore, we developed a one-step superhydrophobic coating on the Ti surface by using a low-pressure plasma technology to create a biocompatible coating that reduces polymicrobial biofilm adhesion and formation. The superhydrophobic coating on Ti was created by the glow discharge plasma using Ar, O2, and hexamethyldisiloxane gases, and after full physical, chemical, and biological characterizations, we evaluated its properties regarding oral biofilm inhibition. The newly developed coating presented an increased surface roughness and, consequently, superhydrophobicity (contact angle over 150°) and enhanced corrosion resistance (p < 0.05) of the Ti surface. Furthermore, proteomic analysis showed a unique pattern of protein adsorption on the superhydrophobic coating without drastically changing the biologic processes mediated by proteins. Additionally, superhydrophobic treatment did not present a cytotoxic effect on fibroblasts or reduction of proliferation; however, it significantly reduced (≈8-fold change) polymicrobial adhesion (bacterial and fungal) and biofilm formation in vitro. Interestingly, superhydrophobic coating shifted the microbiological profile of biofilms formed in situ in the oral cavity, reducing by up to ≈7 fold pathogens associated with the peri-implant disease. Thus, this new superhydrophobic coating developed by a one-step glow discharge plasma technique is a promising biocompatible strategy to drastically reduce microbial adhesion and biofilm formation on Ti-based biomedical implants.

Targeting Pathogenic Biofilms: Newly Developed Superhydrophobic Coating Favors a Host-Compatible Microbial Profile on the Titanium Surface.

Fast Fabrication of Superhydrophobic Titanium Alloy as Antibacterial Surface Using Nanosecond Laser Texturing

Antibacterial and cytocompatibility study of modified Ti6Al4V surfaces through thermal annealing.

Silicone insulators are gaining its importance in the transmission and distribution of the power system networks. This study proposes a simple and high throughput way of fabrication of superhydroph...

Fabrication of self-cleaning superhydrophobic silicone rubber insulator through laser texturing

Nanostructured polymeric film has wide range of applications in different fields. However, the existing processes of fabrication of nanostructures on polymer surfaces are limited to very small area and throughput of the processes is very low. In order to solve this challenge, the indigenous hot embossing setup was developed which is capable of patterning micro-nano structures on large area. In this work, the steps for the development of hot embossing setup are discussed. The setup requires nanostructured mould, copper-chromium block, pencil heaters and temperature controlled system (thermostat and thermocouple). Two different types of nanostructures (groove and pillars) were successfully replicated on polystyrene film. The fabricated nanostructures were characterised using field emission scanning electron microscope and atomic force microscope. The dimensions of fabricated nanostructures are close to the mould dimensions with few defects (shrinkage defects). The wettability test was performed using goniometer on plain and structured polystyrene film to study the effect of structures on the wettability of the surface. It was observed that the hydrophilic (water droplet contact angle: 43°) polystyrene film got converted into hydrophobic (water droplet contact angle: 102-112°) nature. The fabricated structured surfaces have shown antibiofouling property which was confirmed through plate counting method.

Development of hot embossing setup and fabrication of ordered nanostructures on large area of polymer surface for antibiofouling application

The major challenge faced in biomedical field is the formation of biofilm on polymer devices like catheters. It is important to functionalize the biomedical devices with a bactericidal agent through an easy and safe process in order to protect them from bacterial attack. In this article, the new method of impregnation of silver nanoparticles (AgNPs) into polymer film was proposed and tested against bacterial cells. The different sizes of silver nanoparticles were embedded in polystyrene film using thermal annealing and soft molding technique. Silver films having different thickness were deposited on the highly polished machinable glass ceramic (MACOR) substrate using direct current (DC) sputtering and subjected to at 750 °C for 15 min. After the heat treatment, AgNPs were formed on MACOR sample. It was then characterized using field emission scanning electron microscope (FE-SEM). Image-J software was used to analysed shape, size and distribution of AgNPs. The spin coating method was adopted to coat polystyrene film on to MACOR substrate supported AgNPs and allow it to cure for 24 h. After curing, the polystyrene film was peeled off and finally, AgNPs got transferred to polystyrene film. The AgNPs embedded polystyrene film was analyzed using FE-SEM and atomic force microscopy (AFM). Spread plate (plate counting) method was used to evaluate the bacterial killing potential of modified polystyrene film against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. The modified polystyrene film shows effective antibacterial ability against both the types of bacteria compared to the plain polystyrene surface.

https://iopscience.iop.org/article/10.1088/2053-1591/aaf916/pdf

P. V. Rao

Papers

Fast Fabrication of Superhydrophobic Titanium Alloy as Antibacterial Surface Using Nanosecond Laser Texturing

Antibacterial and cytocompatibility study of modified Ti6Al4V surfaces through thermal annealing.

Fabrication of self-cleaning superhydrophobic silicone rubber insulator through laser texturing

Development of hot embossing setup and fabrication of ordered nanostructures on large area of polymer surface for antibiofouling application

Fabrication of silver nanoparticles-embedded antibacterial polymer surface through thermal annealing and soft molding technique