Lensless holographic microscope–integrated magnetic levitation platform for measuring the viscosity and density of liquids

Abstract

The invention relates to a lensless holographic microscope-integrated magnetic levitation platform for measuring the viscosity and density of liquids in a microcapillary channel, and to the operating method of said platform. The method of the invention provides the measurement of the viscosity and density of solutions in a portable platform that uses microparticles as a kind of microsensor with magnetic levitation technique, by correlating the levitation speed and height of said microparticles with the viscosity and density of the solution. Furthermore, the integration of a lensless holographic microscope into the platform allows for the visualization and processing of the microparticles levitating within the solution.

Description

[0001] DESCRIPTION

[0002] LENSLESS HOLOGRAPHIC MICROSCOPE-INTEGRATED MAGNETIC

[0003] LEVITATION PLATFORM FOR MEASURING THE VISCOSITY AND DENSITY OF LIQUIDS

[0004] Technical Field of the Invention

[0005] The invention relates to a lensless holographic microscope-integrated magnetic levitation platform for measuring the viscosity and density of liquids in a microcapillary channel, and to the operating method of said platform. The method of the invention provides the measurement of the viscosity and density of solutions in a portable platform that uses microparticles as a kind of microsensor with magnetic levitation technique, by correlating the levitation speed and height of said microparticles with the viscosity and density of the solution. Furthermore, the integration of a lensless holographic microscope into the platform allows for the visualization and processing of the microparticles levitating within the solution.

[0006] State of the Art

[0007] Viscosity and density are fundamental properties of a fluid, and their analysis plays a significant role in various industrial, scientific, and engineering applications, directly affecting the quality and performance of many products. For example, the viscosity of chemical substances or industrial liquids determines the product’s functionality and ease of application. Density, on the other hand, affects properties such as volumetric efficiency, portability, and storage capacity of the products. In addition, viscosity and density analyses are important in many industrial sectors for determining product quality and ensuring compliance with standards. These analyses are used to maintain product consistency and enhance customer satisfaction. Moreover, viscosity and density analysis during production processes provides valuable information for process optimization, and the analysis provides valuable data to be used for goals such as improving material flow, using energy and resources efficiently, and reducing waste.

[0008] In viscosity and density analyses, performing measurements of both parameters using a single device brings numerous advantages. Instead of transferring the same sample to multiple devices, conducting the process on a single device is more practical and efficient. When the sample is valuable and in limited quantities, performing viscosity and density measurements on a single device, rather than testing the same sample on multiple devices, results in less sample consumption. The use of a single device also prevents operators from dealing with multiple devices and reduces technical complexity. Additionally, devices that perform viscosity and density measurements simultaneously can generally be integrated with the same software interface or system. This provides a more compatible solution for data analysis, reporting, and process management. However, in the state of the art, combinations of viscometers and densimeters, multifunctional analysis devices, rheometers, and double-arm immersion densitometers are used to enable simultaneous measurement of density and viscosity. These conventional systems have high energy and sample consumption. At the same time, such devices have bulky structures and are costly. In this context, in the state of the art, microelectromechanical systems (MEMS) are used to develop micro-scale devices as alternatives to conventional viscometers, benchtop densitometers, and their combinations. MEMS viscometers, due to their portability, perform better than conventional viscometers in many industries, especially in clinical applications. However, the components of MEMS systems are manufactured in clean rooms at high cost, which increases the unit test cost, and they involve complex mathematical modeling and production procedures. In the state of the art, another principle used for measuring density is the magnetic levitation technique, which is an attractive tool for researchers from various disciplines in the life sciences due to its simplicity, cost-effectiveness, and the minimal effort required for sample handling; however, most importantly, its greatest advantage is that it enables label-free separation of target cells within a heterogeneous solution [1], However, the aforementioned technique cannot be used for the simultaneous measurement of viscosity and density of liquids. Magnetic levitation typically relies on the principle of levitating and stabilizing particles within a liquid under the influence of a magnetic field, and this technique is widely used in particle characterization and suspension analysis.

[0009] A study conducted by Delikoyun et al. in the state of the art relates to a lensless holographic microscope-integrated magnetic levitation-based platform for measuring the density of microparticles within a microcapillary channel [1]. In this study, under the principle of magnetic levitation, the density of microparticles is used as a physical indicator to distinguish between different microparticle populations, and thanks to the lensless holographic microscope on the hybrid platform described, various microparticles to be measured are imaged at equilibrium heights and analyzed by processing these images. The method described in the study measures distinct levitation heights in a paramagnetic medium to detect cell groups with different densities. Furthermore, the document tests cell viability, drug response and differentiation by monitoring characteristic changes in cell densities. However, the lensless holographic microscope system integrated into the magnetic levitation platform described therein only enables the determination of the levitation height specific to the density of the microparticles. In this document, the measurement medium has constant properties and only the particle density property changes. The measurement performed in the document is independent of particle size and is solely dependent on the density of the particle.

[0010] The patent application CZ304430B6 in the state of the art relates to a platform for measuring the density, viscosity, and surface tension of liquids within a chamber. The mentioned platform consists of a measurement element, an electromagnet, a control circuit, and a light barrier formed by two diodes (an LED and a photodiode). The measurement element is a rod with a disk at its lower end that can be immersed in liquids. For viscosity measurement, the measurement element is suspended using the electromagnet. When the electric circuit connected to the electromagnet is interrupted at short and regular intervals, the measurement element enters free fall. Once the circuit is reactivated, the measurement element is pulled back again and oscillates until the system reaches equilibrium. The levitation of the measurement element is adjusted via the control circuit based on feedback from the light barrier. Signals from the light barrier are read through a transducer and compared with mechanical values. The damping of the oscillations is correlated with the viscosity of the liquid. During density measurement, no oscillation or vibration measurement is performed; however, the current passing through the solenoid coil is recorded and the measured current is correlated with the density of the liquid. In the mentioned platform, the measurement element and measurement chamber are used for each solution without replacement. It is essential to clean the chamber and the measuring element very well between measurements. Otherwise the risk of contamination is high. This issue is particularly critical in the context of precise measurements of biological liquids.

[0011] Due to the limitations and inadequacies of existing technical solutions, such as the high sample volume requirements and elevated risk of contamination in systems that simultaneously measure viscosity and density of liquids, the increased unit test cost and overall expense of conventional techniques, their reliance on complex mathematical modeling and manufacturing procedures, and the use of magnetic levitation technique solely for measuring microparticle density, it has become necessary to develop an improvement in the relevant technical field.

[0012] Brief Description and Objects of the Invention

[0013] The invention describes a lensless holographic microscope-integrated magnetic levitation platform for measuring the viscosity and density of liquids in a microcapillary channel, and the operating method of said platform. In the aforementioned hybrid platform, viscosity measurement is based on drag force, whereas density measurement is based on the buoyant force generated by rotating the platform and utilizing gravitational acceleration. This principle uses microparticles of fixed size and density as a type of microsensor to characterize their motion in different solutions within a paramagnetic medium. Furthermore, the integration of a lensless holographic microscope into the platform allows for the visualization and processing of the microparticles levitating within the solution.

[0014] The object of the invention is to provide a platform capable of simultaneously measuring the viscosity and density of liquids, while enabling the visualization and processing of microparticles. In the invention, the dual-configuration structure allows for the simultaneous measurement of density and viscosity of the liquid. Additionally, in the platform of the invention, after the image sensor (CMOS) detects the hologram images of the microparticles, the angular spectrum method converts the hologram images acquired on the sensor into object images, which are then reconstructed using the back- propagation technique. Since this reconstruction process does not require any manual focusing on the microparticles to be visualized, it allows for the determination of microparticle positions independently from environmental conditions and user-induced errors.

[0015] Another object of the invention is to perform viscosity and density measurement of liquids quickly and at low cost. A cost-effective solution is provided due to the platform components consisting of an LED, magnets, and a pinhole, and the use of a low volume of solutions. Since the structure excludes expensive components such as lenses, objectives, mirrors, and laser sources, it offers an economic advantage. Under the principle of magnetic levitation, measurements conducted in a paramagnetic medium of a defined concentration are completed in less than 7 minutes. The duration of analysis can also be adjusted by changing the concentration.

[0016] Another object of the invention is to enable the determination of both viscosity and density of liquids using a low sample volume. The platform of the invention performs measurements with only 5-30 pL of liquid.

[0017] Another object of the invention is to eliminate the risk of contamination during viscosity and density analyses. In the platform of the invention, the microparticles and the microcapillary channel are replaced after each measurement, thereby preventing any contamination that a previously measured solution may cause in subsequent measurements.

[0018] Description of Figures

[0019] Figure 1. Measurement principle of the holographic microscope-integrated magnetic levitation-based platform (A: viscosity measurement configuration, B: density measurement configuration).

[0020] Figure 2. Representation of the magnetic levitation platform. A microcapillary channel illuminated by the holographic microscope components placed between two opposing magnets. (A. Ambient light cover; B. Main body containing the magnets, microcapillary channel, and lensless holographic microscope components)

[0021] Figure 3. Processed hologram images of the microparticles within the microcapillary placed between two magnets.

[0022] Figure 4. Correlation graph between the levitation time of microparticles and the known viscosities of the solutions.

[0023] Figure 5. Density analysis of microparticles at 200 mM Gadolinium (Gd3+) concentration (reconstructed images of A-D: 50-10% by weight of and E-H: 5-2% by weight of glycerol solutions).

[0024] Figure 6. Correlation graph between the levitation height of microparticles and the known densities of the solutions. Description of Reference Numerals in the Figures

[0025] 1. Ambient light cover

[0026] 2. Main body

[0027] 3. Magnet

[0028] 4. Microcapillary channel

[0029] 5. Paramagnetic solution

[0030] 6. Light source

[0031] 7. Image Sensor

[0032] 8. Pinhole

[0033] Detailed Description of the Invention

[0034] The invention relates to a lensless holographic microscope-integrated magnetic levitation platform for measuring the viscosity and density of liquids in a microcapillary channel, and to the operating method of said platform. In the aforementioned hybrid platform, viscosity measurement is based on drag force, whereas density measurement is based on the buoyant force generated by rotating the platform and utilizing gravitational acceleration. This principle uses microparticles of fixed size and density as a type of microsensor to characterize their motion in different solutions within a paramagnetic medium. Furthermore, the integration of a lensless holographic microscope into the platform allows for the visualization and processing of the microparticles levitating within the solution.

[0035] The lensless holographic microscope-integrated magnetic levitation platform of the invention comprises at least two magnets (3), one positioned at the top level of the platform and one at the bottom level of the platform, which have opposite poles facing each other for density measurement, are positioned horizontally opposite each other in the same alignment for viscosity measurement and used to levitate microparticles, at least one microcapillary channel (4) containing the sample solution, at least one light source (6) for illuminating the sample, at least one pinhole (8) to convert the light source into a point light source, a non-ionic paramagnetic solution (5) for the levitation of microparticles within a solution sample placed inside a microcapillary located between opposing magnets, and at least one image sensor (7) to capture the image of the microparticles. The aforementioned magnet (3) is an N52 grade neodymium magnet (NdFeB) with dimensions of 2x5x50 mm. The microcapillary channel (4) has the dimensions of 1 x1 x50 mm, and the pinhole (8) has a size of 50-200 pm, preferably 150 pm. The light source (6) used is a white LED light, and the image sensor (7) is a CMOS. The LED light is in the range of the 395-530 nm. The platform of the invention is manufactured from generic polylactic acid (generic PLA) material. As seen in Figure 2, the final CMOS-to-sample distance (z3) is 1 mm, the sample-to-pinhole distance (z2) is 50 mm. The LED-to-pinhole (8) distance (zi) is 20 mm. The geometry suitable for holding two magnets at a fixed distance of 1 .7 mm and aligned with the imaging elements was designed using 3D CAD software.

[0036] In an embodiment of the invention, a single magnet (3) is used prior to the measurement in order to align the microparticles along the same position on the wall of the microcapillary channel. In this way, when the microparticles are positioned between the opposing magnets of the magnetic levitation platform, they begin their movement from the same location within the capillary. For viscosity analysis of the solution, it is critical that the microparticles initiate movement from the same position. This reduces error margin during measurement and increases the accuracy of the results. The lensless holographic microscope-integrated magnetic levitation platform of the invention is arranged in an upright configuration in which the opposing magnets are aligned horizontally for viscosity measurement. In this platform, particles tend to move toward the center point of two magnets, where magnetic induction is at a minimum. The particles continue to move within the solution until the magnetic force acting thereon becomes zero. During this displacement, a drag force acts in the opposite direction of the motion. The theoretical Equation 1 , which represents the forces acting on the microparticle, is used to calculate the viscosity of the solution:

[0037] Equation 1

[0038] Here, (^) denotes the difference in magnetic susceptibility between the microparticle and the medium (with Gd3+magnetic susceptibility assumed to be 3.2x10-4M-1); is the vacuum permeability (1.2566x10-6kg- m- A-2- s-2); and (S) represents the magnetic induction value calculated using FEM. Additionally, (^) is the radius of the microparticle; ( >) is the drag coefficient ( / i>=1 for microparticles far from the microfluidic channel wall); (v) is the speed of the microparticle; and is the dynamic viscosity of the medium. As shown in the equation, the microparticle size affects the equilibrium speed and thus the equilibrium time in proportion to the square of its radius. In other words, as the particle gets smaller, its speed decreases accordingly. The equation also indicates that as the sample becomes more viscous, the equilibrium speed of the particle decreases. Using this principle, the viscosity of a solution can be determined by measuring the equilibrium time of the particle within the capillary channel. The platform is rotated 90° into a horizontal configuration in order to position the opposing magnets vertically for performing solution density measurements based on magnetic levitation, wherein this rotation can be carried out either manually or via a motorized mechanism. In this configuration, due to differences in magnetic susceptibility with the surrounding environment, the microparticles tend to move from the higher magnetic induction to the lower magnetic induction. The microparticles then stabilize at a certain levitation height when the magnetic and buoyancy forces balance each other. The force acting on the microparticle used to calculate the density of the solution is represented by the theoretical Equation 2, as given below:

[0039] In this equation, (g) represents the gravitational acceleration and ,?3denote the volumetric densities of the microparticle and the medium, respectively. For a given microparticle density, if the solution density is higher than the particle density (

[0040] < p,,3), the particle is stabilized above the magnetic midpoint. Similarly, if the solution density is lower than the particle density ( ), the particle is stabilized below the magnetic midpoint. When the solution and particle densities are equal (p. =TO), the microparticles are stabilized at the midpoint. The size of the microparticle does not affect the measurement characteristic. The density of the solution is calculated using this principle by measuring the levitation height of a microparticle of known density in the microcapillary channel (4) manually or by image analysis methods. The image analysis methods mentioned here are segmentation, object recognition, machine learning or deep learning algorithms, or motion analysis. The microparticles under analysis are imaged within the microcapillary using the integrated lensless holographic microscope. For this purpose, a CMOS and an LED are connected to a mini computer, which provides power and captures holographic images. The LED emits light waves that pass through the pinhole (8) and illuminate the microparticles within the microcapillary channel (4). When the wave resulting from the interaction between the reference wave and the object reaches the image sensor (7), the CMOS captures the hologram images of the microparticles. A custom-developed software code controls the imaging time and frequency, enabling the image sensor (7) to record the holograms of the particles. The holographic images captured during the experiment are then reconstructed to generate real object images. When the reference wave emitted by the light source (6) and the wave generated by the interaction of this wave with the object on the sample are combined on the image sensor (7), the hologram images of microparticles are obtained. After these images are digitally recorded, they are digitally scanned using the angular spectrum method starting from the axis of the image sensor (7) to the focal height where the microparticles are located.

[0041] The operating method of the lensless holographic microscope-integrated magnetic levitation platform of the invention comprises the process steps of i. spatially filtering the light by placing the pinhole (8) in front of the light source (6), ii. aligning the microparticles within the sample, which is placed in a microcapillary channel adjacent to a single magnet, along the wall of the microcapillary channel, iii. illuminating the sample inside the microcapillary channel (4), which is placed between two magnets (3) with the same poles facing each other horizontally for viscosity measurements, in front of the image sensor (7), iv. digitally recording the resulting hologram images at intervals of 0.01 -10 seconds, v. rotating the platform by 90° and illuminating the sample inside the microcapillary channel (4), which is placed between two magnets (3) with the same poles facing each other vertically for density measurements, in front of the image sensor (7), vi. digitally recording the resulting hologram images at intervals of 0.01 -10 seconds, vii. digitally reconstructing the recorded hologram images to determine the focal height of the microparticles, viii. measuring the levitation speed and height of the microparticles to measure the viscosity and density characteristics specific to the solution. In the method of the invention, the microparticle used in step (viii) has a density of 0.9- 1.1 g cm3and a size in the range of 1 -150 pm, respectively, and is preferably a polyethylene particle with a density of 1 .05 g cm3and a diameter of 15 pm.

[0042] In the invention, the velocities of the microparticles introduced into the platform are calculated to generate a calibration curve for viscosity measurement (Figure 1 -A). To obtain consistent results, a microcapillary containing the sample, microparticles, and Gd3+(Gadolinium) is placed next to a single magnet (3). This causes the microparticles to be pushed toward and aligned along the wall of the capillary channel. The capillary is then positioned between two opposing magnets and imaged. To determine the speed of the particles on these processed images, the time from the initial position to the final position is measured. To analyze the particles, reference positions are selected between the capillary wall and the center line. It is observed that image quality degrades as the particles approach the capillary wall and the movement of the microparticles is very slow as they approach the centerline. Accordingly, the reference start and end positions are chosen to be 260 pm (hi line in Figure 3) and 60 pm (hf line in Figure 3) away from the centerline. Thus, the acting magnetic forces remain constant at both positions, and the equilibrium time of the particles is measured over a fixed distance of 200 pm during analysis.

[0043] The equilibrium times of the particles are determined at 26 ± 1°C in solutions containing 50%, 40%, 30%, 20%, 10%, 5%, 4%, 3%, 2%, 1%, and 0% by weight of glycerol. The equilibrium times corresponding to the known viscosities of each solution and the resulting calibration curve are shown in Figure 4-A. A nonlinear relationship is observed between the microparticle equilibrium time and the solution viscosity. For each Gd3+concentration of 200, 100 and 50 mM, an exponential curve fitting is obtained with R2values of 0.97, 0.99, and 0.99, respectively. The equations for curve fittings are as follows: y=28.59e°’3482x, y=130.4e°’2245x, y=208.4e°’2289x. In these equations, y represents the time in seconds for microparticles to reach equilibrium in a paramagnetic medium, and x represents the solution viscosity in cP. These measurements show a gradual increase in microparticle levitation time as the viscosity of the liquid increases. Additionally, as the molarity of the paramagnetic solution decreases, the rate of change in microparticle levitation time increases with the degree of viscosity. This relationship changes the scope of viscosity measurement accuracy and speed. The results demonstrate that even small changes in viscosity can be detected with high precision in low paramagnetic media with a larger levitation time. Specifically, the time required to measure 1 -3 cP viscosity corresponds to 335.2 ± 62.2, 216.9 ± 43.0 and 59.7 ± 16.7 seconds at 50, 100 and 200 mM Gd3+, respectively. On the other hand, higher viscosities are measured more rapidly in higher-concentration paramagnetic medium. For the 1 -10 cP viscosity range, the measurement times are 15.1 ± 9.5, 10.6 ± 7.1 , and 5.1 ± 4.7 minutes at 50, 100, and 200 mM Gd3+, respectively. The viscosity range can also be changed by tuning the Gd3+concentration.

[0044] Since the viscosity of a solution is highly dependent on temperature, the levitation time of microparticles is measured within a low-viscosity range (i.e., <1 .5 cP) at 26 ± 1 °C and 37 ± 1 °C (Figure 4-B). At 26 ± 1°C, each Gd3+concentration results in a fitting line with R2values of 0.92, 0.95 and 0.92 for 200, 100 and 50 mM, respectively. The fitting equations corresponding to these concentrations are as follows: "y = 66.57x - 43.94", "y = 135x + 2.296", and "y = 145.5x + 99.26". Similarly, at 37 ± 1 °C, a linear fitting is obtained for each Gd3+concentration with R2values of 0.96, 0.95 and 0.95 for 200, 100 and 50 mM, respectively. The fitting equations corresponding to these concentrations are as follows: "y = 1 12.6x - 90.67", "y = 143.7x - 91.19", and "y = 175x - 78.91 ". In these measurements, the viscosity range of 1.26-0.97 cP at 26°C is reduced to 1.01-0.84 cP for the same solutions at 37°C. These results indicate that even at decreasing viscosity values, a narrower range can be detected by analyzing microparticle speed. As the viscosity decreases with increasing temperature, the microparticle speed also increases. It is also seen that the rates of these changes increase as the Gd3+concentration decreases. The effect of temperature on the lower viscosity range is more pronounced in 100 and 50 mM Gd3+media.

[0045] In the platform of the invention, the platform is rotated by 90° to measure the density of the solution (Figure 1 -B). A calibration curve for density measurement is obtained by calculating the levitation height of the microparticles introduced into the platform (Figure 6). The levitation heights of these particles are measured in solutions containing 50, 40, 30, 20, 10, 5, 4, 3, 2, 1 and 0% by weight of glycerol and 200, 100 and 50 mM Gd3+. The prepared solutions have density of 1.335, 1.0887, 1.0647, 1.0415, 1.0194, 1.0087, 1.0066, 1.0045, 1.0024, and 1.0024 g. cm-3. The levitation height of microparticles with a density of 1.05 g. cm-3is determined by measuring the distance between their final equilibrium position in the channel and the bottom magnet (Figure 5). The results demonstrate a linear relationship between levitation height and solution density, with R2 values of 0.91 , 0.95, and 0.96 for Gd3+concentrations of 200, 100, and 50 mM. The linear functions used to measure the density of the solutions are expressed as follows: y = 3793x - 3092, y = 10799x - 10449 and y = 12686x - 12467. In these equations, y represents the levitation height of the microparticles in micrometers relative to the bottom magnet, and x represents the solution density in g em-3. As the concentration of Gd3+ions increases, the slope of the line decreases, thereby expanding the measurable density range. For instance, with 50 mM Gd3+, the range is 1 .011 -1 .089 g.cm-3, while with a concentration of 100 mM, this range extends to 1.004-1.096 g.cm-3. The widest density range of 0.918-1.182 g / cm3is achieved with 200 mM Gd3+. The resolution of density of the solution can be tuned from 7.88x10-5to 2.6x10’4g cm’3m’1by increasing the Gd3+concentration from 50 mM to 200 mM. The linear function lines for Gd3+intersect at 1.05 g cnr3, which corresponds to the microparticle used in these measurements. The time required for analysis depends on the distance to the specific equilibrium levitation height, the Gd3+concentration, and the viscosity and density of the solution. As the Gd3+concentration increases, the rate of reaching the levitation height specific to the solution density decreases and the analysis time shortens. On average, the particle reaches equilibrium in less than 5 minutes.

[0046] FBS (fetal bovine serum) solutions were measured using viscosity and density calibration at Gd3+concentrations of 200, 100 and 50 mM. The viscosity of FBS was measured at 26°C with error % of 0.056 ± 0.078, 0.092 ± 0.199 and 0.415 ± 0.566 at 200, 100 and 50 mM Gd3+. Additionally, at 37°C, the viscosity of the FBS solution could be measured with error % of 1.486 ± 1.035, 0.346 ± 0.549, and 0.002 ± 0.174. It was demonstrated that the density of FBS is outside the measurable range at 50 mM Gd3+, and could be detected with error % of 0.008 ± 0.017 and 0.005 ± 0.004 at 200 and 100 mM Gd3+, respectively.

[0047] Industrial Applicability of the Invention

[0048] The invention relates to a lensless holographic microscope-integrated magnetic levitation platform for measuring the viscosity and density of liquids in a microcapillary channel, and to the operating method of said platform, and is industrially applicable.

[0049] The invention is not limited to the above descriptions, and a person skilled in the art can easily come up with different embodiments of the invention. These should be considered within the scope of protection as defined by the claims. REFERENCES

[0050] [1] Delikoyun K;Yaman S;Yilmaz E;Sarigil O;Anil-lnevi M;Telli K;Yalcin-Ozuysal

[0051] O;Ozcivici E;Tekin HC; (n.d.). Hologlev: A hybrid magnetic levitation platform integrated with Lensless holographic microscopy for density-based cell analysis. ACS sensors. https: / / pubmed.ncbi.nlm.nih.gov / 34124887 /

Claims

CLAIMS1 . A lensless holographic microscope-integrated magnetic levitation platform, characterized in that it comprises• at least two magnets (3), one positioned at the top level of the platform and one at the bottom level of the platform, which have opposite poles facing each other for density measurement, are positioned horizontally opposite each other in the same alignment for viscosity measurement and used to levitate microparticles,• at least one microcapillary channel (4) that contains the sample solution,• at least one light source (6) for illuminating the sample,• at least one pinhole (8) to convert the light source into a point light source,• a non-ionic paramagnetic solution (5) for the levitation of microparticles within a solution sample placed inside a microcapillary located between opposing magnets,• at least one image sensor (7) to capture the image of the microparticles.

2. A platform according to claim 1 , characterized in that the magnet (3) is a neodymium magnet (NdFeB) with the dimensions of 2x5x50 mm.

3. A platform according to claim 1 , characterized in that the microcapillary channel(4) has the dimensions of 1 x 1 x50 mm and the pinhole (8) has a size in the range of 50-200 pm.

4. A platform according to claim 1 , characterized in that the light source (6) is a white LED light and the image sensor (7) is a CMOS.

5. A platform according to claim 1 , characterized in that the platform is manufactured from the generic polylactic acid (generic PLA) material.

6. A platform according to claim 1 , characterized in that the paramagnetic solution(5) contains Gd3+(Gadolinium).

7. A platform according to claim 3, characterized in that the pinhole (8) has a size of 150 pm.

8. A platform according to claim 4, characterized in that the LED light is in the range of 395-530 nm.

9. A platform according to claim 6, characterized in that the Gd3+is in the range of 50-200 mM.

10. An operating method of a lensless holographic microscope-integrated magnetic levitation platform, characterized in that it comprises the process steps of i. spatially filtering the light by placing the pinhole (8) in front of the light source (6), ii. aligning the microparticles within the sample, which is placed in a microcapillary channel adjacent to a single magnet, along the wall of the microcapillary channel, iii. illuminating the sample inside the microcapillary channel (4), which is placed between two magnets (3) with the same poles facing each other horizontally for viscosity measurements, in front of the image sensor (7), iv. digitally recording the resulting hologram images at intervals of 0.01 -10 seconds, v. rotating the platform by 90° and illuminating the sample inside the microcapillary channel (4), which is placed between two magnets (3) with the same poles facing each other vertically for density measurements, in front of the image sensor (7), vi. digitally recording the resulting hologram images at intervals of 0.01 -10 seconds, vii. digitally reconstructing the recorded hologram images to determine the focal height of the microparticles, viii. measuring the levitation speed and height of the microparticles to measure the viscosity and density characteristics specific to the solution.1 1 . A method according to claim 10, characterized in that the density measurement in step (viii) comprises the process step of calculating the levitation height of the microparticles introduced into the platform.

12. A method according to claim 10, characterized in that the viscosity measurement in step (v) comprises the process step of calculating the levitation speed or the equilibrium time of the microparticles introduced into the platform.

13. A method according to claim 10, characterized in that the density measurement is performed theoretically in accordance with Equation 2 or based on the calibration curves specific to the platform.Equation 214. A method according to claim 10, characterized in that the viscosity measurement is performed theoretically in accordance with Equation 1 or based on the calibration curves specific to the platform.

15. A method according to claim 10, characterized in that the microparticle in step (viii) has a density in the range of 0.9-1.1 g em-3and a size in the range of 1 - 150 micrometers.

16. A method according to claim 1 1 , characterized in that the levitation height calculation is performed manually or using image analysis methods.

17. A method according to claim 13, characterized in that for the measurement of solutions with viscosity lower than 1.5 cP at 37°C in 200, 100 and 50 mM Gadolinium, the calibration curves "y = 1 12.6x - 90.67", "y = 143.7x - 91.19", and "y = 175x - 78.91" are used, respectively.

18. A method according to claim 13, characterized in that the calibration curves for 200, 100 and 50 mM Gadolinium are, respectively, y = 3793x - 3092, y = 10799x - 10449, and y = 12686x - 12467.

19. A method according to claim 14, characterized in that the calibration curves for 200, 100 and 50 mM Gadolinium are, respectively, y=28,59e°’3482x, y=130,4e°’2245xand y=208,4e°’2289x.

20. A method according to claim 14, characterized in that for the measurement of solutions with viscosity lower than 1.5 cP at 26°C in 200, 100 and 50 mM Gadolinium, the calibration curves "y = 66.57x - 43.94", "y = 135x + 2.296", and "y = 145.5x + 99.26" are used, respectively. 21 . A method according to claim 15, characterized in that the microparticle is a polyethylene particle with a density of 1.05 g em-3and a diameter of 15 pm.

22. A method according to claim 16, characterized in that the image analysis methods are segmentation, object recognition, machine learning or deep learning algorithms, or motion analysis.

Images