A set of electrostatically charged, fluorescent, and superparamagnetic nanoprobes was developed for targeting cancer cells without using any molecular biomarkers. The surface electrostatic properties of the established cancer cell lines and primary normal cells were characterized by using these nanoprobes with various electrostatic signs and amplitudes. All twenty two randomly selected cancer cell lines of different organs, but not normal control cells, bound specifically to the positively charged nanoprobes. The relative surface charges of cancer cells could be quantified by the percentage of cells captured magnetically. The activities of glucose metabolism had a profound impact on the surface charge level of cancer cells. The data indicate that an elevated glycolysis in the cancer cells led to a higher level secretion of lactate. The secreted lactate anions are known to remove the positive ions, leaving behind the negative changes on the cell surfaces. This unique metabolic behavior is responsible for generating negative cancer surface charges in a perpetuating fashion. The metabolically active cancer cells are shown to a unique surface electrostatic pattern that can be used for recovering cancer cells from the circulating blood and other solutions.

Targeted drug delivery by nanoparticles (NPs) is an essential technique to achieve the ideal therapeutic effect for cancer. However, it requires large amounts of work to imitate the biomarkers on the surface of the cell membrane and cannot fully retain the bio-function and interactions among cells. Cell membranes have been studied to form biomimetic NPs to achieve functions like immune escape, targeted drug delivery, and immune modulation, which inherit the ability to interact with the in vivo environments. Currently, erythrocyte, leukocyte, mesenchymal stem cell, cancer cell and platelet have been applied in coating photothermal agents and anti-cancer drugs to achieve increased photothermal conversion efficiency and decreased side effects in cancer ablation. In this review, we discuss the recent development of cell membrane-coated NPs in the application of photothermal therapy and cancer targeting. The underlying biomarkers of cell membrane-coated nanoparticles (CMNPs) are discussed, and future research directions are suggested.

Over the past decades, cell surface charge, although experimentally observed, has not been well understood particularly from the viewpoint of biophysics. Our recent studies have shown that all cancer cells exhibit negative surface charges that are directly proportional to the secreted lactic acid, a unique cancer metabolic characteristic: high rate of glycolysis. We have therefore designed and developed a set of electrically-charged, fluorescent, and super-paramagnetic nanoprobes, capable of sensitive detection of cancer cells based on the surface charges. These probes are utilized to bind onto cells via electrostatic reaction for capture and magnetic separation. In this fashion, we are able to characterize cell surface charges that are regulated by different metabolic patterns, therefore effectively distinguishing the cancer cells from the normal cells. All 22 cancer cells of different organs are found to be negatively-charged therefore bound strongly by the positively-charged nanoprobes, whereas the normal cells show insignificant binding to the nanoprobes of either charge signs (positive or negative). This finding suggests that all tested cancer cells are negatively-charged and normal cells are either charge-neutral or slightly positive. For diagnosis, cancer cells can be detected, electrostatically bound, and magnetically separated in blood by charged and super-paramagnetic nanoprobes. In therapeutics, circulating cancer cells (CTCs) can be filtered and removed in a continuous fashion to reduce the risk of cancer metastasis. If successful, this new nanotechnology will revolutionize early cancer diagnosis and potentially enable new therapeutics in clinical settings.