Micromanipulation is considered a challenging task which requires high precision motion and measurement at the micro scale. When micromanipulation is concerned with living organisms important considerations need to be addressed. These include the physical or chemical properties of micro-organisms, living conditions, responses to the environment and achieving suitably delicate manipulation. Bio-micromanipulation can include micro surgery or cell injection operations, or to determine interaction forces as the basis to investigate behavior and properties of living micro-organisms. In order to achieve suitable bio-micromanipulation appropriate processes and/or sensory systems need to be investigated. This thesis aims to look into the force interaction and sensing addressing two distinctive challenges in the field of bio-micromanipulation. To this end, this thesis presents two major contributions to advancing bio-micromanipulation. Firstly, a novel Haptic Microrobotic Cell Injection System is introduced which is able to assist a bio-operator through haptic interaction. The system introduces a mapping framework which provides an intuitive method for the bio-operator to maneuver the micropipette in a manner similar to handheld needle insertion. To accurately control the microrobot, a neuro-fuzzy modeling and control scheme has been developed. Volumetric, axial and planar haptic virtual fixtures are introduced to guide the bio-operator during cell injection. Aside from improving real-time operator performance using the physical system, the system is novel in facilitating virtual offline operator training. Secondly, a first-of-its-kind micro-pillar based on-chip system for dynamic force measurement of C. elegans motion is introduced. The system comprises a microfabricated PDMS device to direct C. elegans into a matrix of micropillars within a channel mimicking its dwelling environment. An image processing algorithm is able to track the interaction of the C. elegans with the pillars and estimate contact forces based on micropillar deflections. The developed micropillar system is capable of measuring the force with sub-micron resolution while providing a continuous force output spectrum.

Miniature compliant grippers are designed and developed to manipulate biological cells and characterize them. Apart from grippers, other compliant mechanisms are also demonstrated to be effective in manipulation and characterization. Although scalability and force-sensing capability are inherent to a compliant mechanism, it is important to design a compliant mechanism for a given application. Two techniques based on Spring-lever models and kinetoelastostatic maps are developed and used for designing compliant devices. The kinetoelastostatic maps-based technique is a novel approach in designing a mechanism of a given topology and shape. It is also demonstrated that these techniques can be used to tune the stiffness of a mechanism for a given application. In situations where any single mechanism is incapable of executing a specific task, two or more mechanisms are combined into a single continuum with enhanced functionality. This has led to designs of composite compliant mechanisms. Biological cells are manipulated using compliant grippers in order to study their mechanical responses. Biological cells whose size varies from 1 mm (a large zebrafish embryo) to 10 µm (human liver cells), and which require the grippers to resolve forces ranging from 1 mN (zebrafish embryo) to 10 nN (human cells), are manipulated. In addition to biological cells, in some special cases such as tissue-cutting and cement-testing, inanimate specimens are used to highlight specific features of compliant mechanisms. Two extreme cases of manipulation are carried out to demonstrate the efficacy of the design techniques. They are: (i) breaking a stiff cement specimen of stiffness 250 kN/m (ii) gentle grasping of a soft zebrafish embryo of stiffness 10 N/m. Apart from manipulation, wherever it is viable, the mechanisms are interfaced with a haptic device such that the user’s experience of manipulation is enriched with force feedback. An auxiliary study on the characterization of cells is carried out using a micro¬pipette based aspiration technique. Using this technique, cells existing in different conditions such as perfusion, therapeutic medicines, etc., are mechanically characterized. This study is to qualitatively compare aspiration-based techniques with compliant gripper-based manipulation techniques. A compliant gripper-based manipulation technique is beneficial in estimating the bulk stiffness of the cells and can be extended to estimate the distribution of Young’s modulus in the interior. This estimation is carried out by solving an inverse problem. A previously reported scheme to solve over specified boundary conditions of an elastic object—in this case a cell—is improved, and the improved scheme is validated with the help of macro-scale specimens.