**2. Bioparticles in biomedical studies**

Manipulation of bioparticles has been a major concern in recent development of micro−/nanofluidic studies due to their potential in biomedical application. Those particles, according to their biological structure and physical properties, can be categorized as (1) model organisms; (2) body cells, which include blood cells, tumor and cancer cells, and stem or progenitor cells; (3) bacteria; (4) viruses; (5) nucleic acids; and (6) proteins.

Model organisms, either unicellular (e.g., yeast) or multicellular (e.g., *Danio rerio* zebrafish, *Caenorhabditis elegans* nematode, etc.), are being used for cellular process studies (cell cycle, cell division, metabolism, etc.), genetic and pharmacological studies, as well as pathogenesis and therapy studies. Blood which composed by two components, i.e., (1) blood plasma and (2) the formed elements, including red blood cells (RBCs), white blood cells (WBCs), and platelets, is of high interest as they are being used in various health check and clinical tests, such as blood test to determine whether our organs (e.g., kidneys, liver, thyroid, heart, etc.) are working properly and to diagnose any disease such as HIV/AIDS, cancer, anemia, diabetes, and coronary heart disease. Tumor cells (benign) and cancer cells (malignant) are cells that undergo uncontrolled proliferation, causing tumor development either at the skin, colon, rectum, prostate, breasts, or lungs. They are grouped either as (1) carcinomas (develop in epithelial cells), (2) leukemia and lymphomas (develop at the blood and lymphatic system), or (3) sarcomas (develop at the connective tissue). These cells attempt to develop secondary tumor (metastasis tumor) by spreading through vascular or blood vessel network in the form of circulating tumor cells (CTCs). Stem cells, either adult stem cells or pluripotent stem cells, are cells that can self-renew, generating perfect copies of themselves by division and differentiation, where the produced cells are specific for certain function in the body. These cells are important in research, drug screening test, and cell transplantation therapy. Bacteria, which are unicellular prokaryotic microorganisms, grow and reproduce rapidly through binary fission. They are important in biomedical studies in the development of disease diagnostic tools and in understanding of biological responses under certain stimuli, according to their actions, either as predators, mutualists, or pathogens, in which pathogenic bacteria demonstrate a parasitic association with other organisms to cause infections. Viruses, which are genes enclosed by a protective coat, are infective agents due to lack of metabolic machinery, hence depending on the host for gene expression. They are important in the study of virus detection as well as the study of virus influence to cells. Nucleic acids, which are biomolecules made from nucleotides as monomers, function in encoding, transmitting, and expressing genetic information. There are two types of nucleic acids in living cells, which are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). They are highly essential in the research of replication, repair, storage and modification of DNA, disease biomarkers, and gene delivery. Proteins are biomolecules constructing a single or a number of long chains of amino acid residues. The discovery of their role within living organisms includes catalyzing metabolic reactions, DNA replication, responding to stimuli and transporting molecules from one location to another, and getting remarkable attention in the biomedical research and application these days.
