Nano-imaging For Dialysis Membrane Surface Characterization Using (AFM)

Nano-imaging For Dialysis Membrane Surface Characterization Using (AFM)

Proposal Summary

The research problem is that while the surface membrane is important to make the interaction with blood cells, proteins, and platelets, there is often a challenge of surface roughness and low hemocompatibility. Yet, blood compatibility is highly influenced by the structure of the surface membranes. Membranes that are made up of rough surfaces tend to bring about poor hemocompatibility and high adhesion of platelets, proteins, and blood cells.

The primary aim of this study is to evaluate how AFM is applied to characterize nanoimaging for the dialysis membrane surface. The research problem is associated with the fact that standard infinitesimal methods do not offer an adequate photograph for assessing the magnitude of the distributed pores. This evaluation will help in assessing how AFM can be utilized to characterize the process of nano-imaging for the dialysis membrane surface. It also offers a literature review detailing numerous sources concerning the use of AFM in hemodialysis. The methodology involved the use of Young’s Modulus determination and AFM.

Introduction

The surface membrane is essential in the process of interaction with blood components such as blood cells, proteins, and platelets. However, existing research suggests that the aspects of surface roughness tend to affect the proper functioning of this process. It is argued that the structure of the surface membranes establishes problems with blood compatibility, which make the process of dialysis difficult. Thus, this study seeks to provide knowledge on how to revamp surface texture to allow efficient blood compatibility and ease the process of dialysis through AFM (Atomic Force Microscopy). The study will add information regarding how to improve surface morphology, reference, charge distribution, toughness, size, energy, and wettability.

The given study seeks to assess how AFM can be utilized to characterize the process of nano-imaging for the dialysis membrane surface. The various instruments of nano-technology including Atomic Force Microscopy (AFM), are currently fetching broad attention in the fields of biomedicine as well as health sciences [1]. The concept of AFM forms a multipurpose practice that facilitates the examination of the nano-scale, active, and automatic features of organic models. These include properties such as active cells, biological molecules, as well as other substances.

Research Problem

The process of estimating the size of pores is imperative for the classification of the layer of dialysis. Nevertheless, the standard miniscule methods do not offer an adequate picture for assessing the size of the pores. The problem is that even with the advancement in the techniques of determining the size of pores, there are still difficulties in locating their positions on biological samples and other physiological tissues normally among human beings.

The systems of infinitesimal observations have received great advancement making them a considerable method. The superficial stomas of the dialysis layers, which have existed for over ten years, are currently being studied thanks to the practice of microscopy [2]. This achievement is because of the AFM’s aptitude to enable the examination of the shape, purpose, features, and interactions of organic models in their natural form regardless of the physical circumstances. However, these samples from the microscopy system should be readied through a procedure of metallic covering, which cannot be evaluated through the examination of photographs. However, the technique of AFM does not require preliminary metallic covering and, therefore, provides advanced firmness. In this particular assessment, the concept of AFM is currently proven to be a strong instrument to be used in viewing and assessing the tiny superficial stomas for the layer of a dialysis membrane [3]. As such, this particular model solving technique explained under and an extremely refined review has made it likely to detect tiny holes on a mushy and undulating exterior of the dialysis layer.

The AFM offers an exceptional and solid observation and also offers data on the unevenness of the surface. In the recent times, the effective and efficient usage of AFM has been made possible to approve the availability of small holes on the surface of the layers.

Objectives

The study seeks to image the surface of dialysis membrane hollow-fibers of different makes used for AFM before and after it has been applied for dialysis.

• To image the surface topography of membrane surfaces to estimate surface roughness and nanomechanical properties before and after use in dialysis process.
• To image the surface topography of re-usable dialysis membrane to discover if blood particles including proteins are adsorbed on the surfaces giving rise to increased surface roughness.

Importance of Research

In general, the study will help in assessing how AFM (Atomic Force Microscopy) can be utilized to characterize the process of nano-imaging for the dialysis membrane surface. The importance of this research is that it will help to determine the process of imaging the surface of dialysis membrane hollow-fibers of different types using AFM before and after it has been used for dialysis [4]. The study will help professionals in this field of dialysis to determine the problems associated with the surface characterization instrument. It will also assist in understanding the process of imaging the surface topography of membrane surfaces to calculate the roughness and nanomechanical properties before and after use in a dialysis process. In addition, it will help in determining new ways of imaging the surface topography of re-usable dialysis membrane to find if blood particles including proteins are adsorbed on the surfaces giving rise to increased surface roughness. Also, the researcher will inspire future research focusing on how to improve the quality of surface images presented during the process of dialysis.

Literature Review

According to Hayama et al [5], the practice of Atomic Force Microscopy has over the years received incessant attention as an instrument of surface characterization. The authors observe that this system has particularly become one of the most prominent nanotool in the field of life sciences and biomedicine. To be precise, this success has come about as a result of the AFM possessing a unique signal-to-noise ratio that eases the production of images with a sub-nanometer resolution. As such, this resolution allows for the investigation of the ultrastructure of a wide variety of samples including cells, DNA, as well as proteins.

As posited by Barzin, et al [6], there has been recent development in the new methods of microscopic observation and this includes AFM. The study revealed that the surface pores membrane dialysis can be studied through electron microscopy. In addition, the authors note that AFM forms one of these methods which does not necessitate preliminary metal covering; hence, providing greater resolution. As a result, the membrane technology has evolved to become a huge industry as they are not only being used in clinical practice for hemodialysis, but also in Reverse Osmosis and Ultrafiltration.

In a research study conducted by Holzweber et al [7], it was discovered that the concept of AFM requires the use of synthetic polymers to produce dialyzer membranes. Typically, AFM has the ability to envisage tissue morphology, biomolecules, and cellular membranes, which enables the clear observation of cell and protein surfaces. The authors argue that the biocompatibility of hydrophilic modifiers in the whole AFM process allows for the measurement of the unevenness of the surface, dimensions, consistency, and volume of organic structures. As such, the ability of the AFM to identify interactions between cells and proteins has created new ideas of investigation and the properties of biological surfaces.

            While studying the process of dialysis, Yamazaki, et al [8], highlighted that the process of hemodialysis is crucial in saving the sick battling CRF. The authors argued that the process of hemodialysis involves the purification of blood where urea mixed in blood is extracted through incidental interaction amid the liquid of dialysis along with the blood of a given patient. Primarily, this is carried out in a hemodialyzer through the dialysis membrane. However, the authors note that clinical dialysis membranes consist of pores of different sizes, deviations, as well as dead-ends. The study used FM to characterize the basic structure of CTA (Cellulose Triacetate) dialysis membrane.

Yamamoto [9] suggested that while the practice of hemodialysis is essential in saving the lives of patients with chronic renal failure, several complications remain inevitable. They observe that the buildup of phosphate ions bringing about the pathologic deposition of calcium salts in soft tissues. It is argued that the moderate low phosphate clearance the process of hemodialysis in the availability of hemodialysis membranes. The authors further propose that the conventional technique such as AFM can be applied to boost the characterization of a given dialysis membrane (Yamamoto et al. 2010).

Research Project Design and Methodology

1. Physical

Nanomechanical Property Determination.

Young’s Modulus Determination using AFM. As observed from the objectives, the topography and images of force spectroscopy will be attained in constant-force method by means of an AFM. The size of the scan will be 5 μm at different positions over a bigger area of the nanofibers. Young’s Modulus for every spot will be estimated by applying the model of Hertz. The figure below shows a dissection of a sample force curve.

The diversion of the cantilever via the approach and retract cycle will be utilized to generate a force-distance plot. From the figure, point 1 represents that the probe and substrate are distant and do not experience any interaction. In the meeting of the probe and substrate, vigour ascends amid the two causing a cantilever deviation that can be estimated. By point 2, an attractive compulsion is unveiled boosting the probe and substrate together. At point 3, the probe and substrate experience contact. End 4 demonstrates that the probe and the surface moving in contact, and the angle of this line estimates the substrate compliance. The course of the incline is altered as the probe and substrate gradually separate at end 5. The extra force that is experienced is because of cohesive interaction. At point 6, the force that is instigated by the cantilever distortion is adequate to conquer the cohesive force and separate the probe and substrate. For a biological system, this is the ligand-receptor interaction force.

The variable factors for the calculation include;

F – Force,

K – Spring constant of the tip

D – Deflection of the tip

E – Elastic Modulus

R – Radius of curvature of the tip

V – Poisson’s ratio or Indentation ratio

∂ – Indentation of the sample.

The population will be monitored to define the standard dispersal. The average Young’s moduli of the points of focus will be exposed using the method of ANOVA (Analysis of Variance) as well as SPSS. Student T-tests will be completed transversely through the axis and diagonal images by means of MS Excel.

1. Wettability

The water contact angle will be estimated using Attension Optical Tensiometer Theta 200 after a consistent procedure in the biomaterials and tissue engineering laboratory.

1. Statistics

All quantification values including Young’s Modulus, water contact angle will be availed as mean ± standard deviation (SD). Following the evaluation with ANOVA, the variations among groups will be recognised with t-test analysis and a two-population comparison. P-values <0.05 will be regarded as statistically important.

References

[1]        K, Krzemien, et al. “Atomic force microscopy of chromatin arrays reveal non-monotonic salt dependence of array compaction in solution.” PLOS ONE, vol. 12, no. 3, p. e0173459. 2017.

[2]        S, Hirayama et al. “Atomic force microscopy imaging of dialyzed single-walled carbon nanotubes dispersed with sodium dodecyl sulfate.” International Journal of Smart and Nano Materials, vol. 4, no. 2, pp. 119-127. 2013.

[3]        T, Tsuruyama et al. “Dialysis Purification of Integrase-DNA Complexes Provides High-Resolution Atomic Force Microscopy Images: Dimeric Recombinant HIV-1 Integrase Binding and Specific Looping on DNA.” PLoS ONE, vol. 8, no. 1, p. e53572. 2013.

[4]        S, Lal et al. “Lipid bilayer-atomic force microscopy combined platform records simultaneous electrical and topological changes of the TRP channel polycystin-2 (TRPP2).” PLOS ONE, vol. 13, no. 8, 2018.

[5]        M, Hayama et al. AFM observation of small surface pores of hollow-fiber dialysis membrane using highly sharpened probe. Journal of Membrane Science, Vol. 197, no.1-2. p.243-249. 2002.

[6]        J, Barzin et al. Characterization of polyethersulfone hemodialysis membrane by ultrafiltration and atomic force microscopy. Journal of Membrane Science, vol.237, no.1-2, p.77-85. 2004.

[7]        M, Holzweber et al. Surface characterization of dialyzer polymer membranes by imaging ToF-SIMS and quantitative XPS line scans. Biointerphases, vol.10, no.1, p.019011. 2015.

[8]        K, Yamazaki et al. Internal and surface structure characterization of cellulose triacetate hollow-fiber dialysis membranes. Journal of Membrane Science, 368(1-2), 34-40. 2011.

[9]        K, Yamamoto et al. Membrane potential and charge density of hollow-fiber dialysis membranes. Journal of Membrane Science, vol.355, no.1-2, p.182-185, 2010.