The improved blood smear device developed at IIT Bombay in collaboration with AGD Biomedical Pvt. Ltd. offers a cost-effective, automated solution for preparing high-quality blood smears. Designed using low-cost, modular components, the device enables uniform smears across a variety of blood viscosities and includes an auto-cleaning mechanism. It is ideal for diagnostic applications in low-resource and decentralized healthcare environments.
Figure 1. Illustration of the full construction of blood smear machine
Accurate blood smear preparation is essential for diagnosing various medical conditions such as malaria, anemia, and blood infections. However, in most diagnostic settings, the smearing process is done manually. This introduces variability in the quality of the smears, often making them unsuitable for reliable analysis. While automated smearing machines are available, they tend to be expensive, bulky, and integrated with additional features like staining and drying-making them inaccessible for small clinics or resource-constrained settings.
- Seven-Speed Blade Control: The device offers seven selectable blade speeds to accommodate blood samples with varying viscosities and surface tensions. This feature ensures optimal film thickness and consistent monolayer smears across different patient samples.
- Torsion Spring-Based Blade Pressure: A torsion spring ensures uniform downward pressure of the blade on the slide throughout the smear process. This enables full contact and smooth spreading, minimizing inconsistencies and edge effects seen in manual smears.
- Precision Motorized Motion: A stepper motor coupled with a lead screw mechanism provides controlled, linear movement of the blade. This setup ensures steady, repeatable blade travel, reducing vibration and enhancing smear consistency.
- Automatic Blade Lift & Cleaning Mechanism: As the blade assembly returns to the cleaning station, a sloped surface causes it to rotate upwards automatically. This feature exposes the smearing edge for easy cleaning, improving hygiene and minimizing manual handling.
- Optical Sensor for Position Reset: An optical sensor detects and resets the blade to a fixed starting position before each smear, ensuring repeatability and operational consistency over multiple cycles.
- 3D-Printed Modular Design: The chassis and key mechanical components are 3D-printed for low-cost fabrication and easy maintenance. This modular design also allows for future upgrades and customization.
- Glass Blade Compatibility: The blade holder is designed to grip cut glass blades, which offer superior wetting with blood, enabling cleaner and more uniform smears ideal for diagnostic microscopy.
The prototype is a compact, automated device designed to prepare uniform blood smears on microscope slides. It features a motor-driven spreader assembly mounted on a base with a slide-holding table, a stepper motor, and a lead screw mechanism for precise linear motion. A glass spreader blade, fixed at a controlled angle using a hinged lever with a torsion spring, ensures consistent contact with the slide. The blade is moved smoothly across the slide using a guide block on linear rods, while the slide remains fixed in a shallow groove on the table.
After completing the smear, the blade returns to a cleaning station, where a sloped surface lifts the blade holder to expose the edge for cleaning. An optical sensor resets the blade position for the next cycle. The device includes a speed control unit with seven selectable speeds to accommodate different blood viscosities and a simple user interface with a start button and power input. Its automation, consistency, and ease of use make it highly suitable for clinical laboratories, mobile diagnostic units, and low-resource settings.
A fully functional prototype of the device has been developed and tested. It demonstrates high-quality and repeatable smear formation using small blood volumes. The system is built with commercially available, cost-effective parts and is now ready for further optimization, clinical validation, and technology transfer for mass production or deployment.
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This innovation improves access to reliable diagnostic tools, especially in underserved and rural healthcare settings. By automating a critical lab process at a low cost, it reduces reliance on skilled technicians and expensive equipment. The result is improved diagnostic accuracy and faster, more consistent healthcare delivery, ultimately contributing to better patient outcomes and public health monitoring.
- Pathology labs
- Rural health centers
- Mobile diagnostic units
- Veterinary diagnostics
- Medical device manufacturing
- Research and academic labs
Geography of IP
Type of IP
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