Bioimprint Mediated Label‐Free Isolation of Pancreatic Tumor Cells from a Healthy Peripheral Blood Cell Population

Abstract

tumor to early metastasize and spread [5] and even the smallest primary lesions often show perineural and lympho-vascular invasion. [6] More recently, the 5-year survival rates have improved slightly but differs from country to country, based on management approaches such as early surgical removal, stage, absence of lymph node metastasis. Worldwide, survival is generally around 5% [2] and it is the fifth most common cause of cancer death in the UK [7] and Europe. [8] In the U.S, PC is the fourth leading cause of cancer death [9] and second most common gastrointestinal malignancy. Surgical resection of the tumor is associated with the best patient outcomes but as stated above due to early tumor spread this is not an option in many cases. Pancreatic cancer is a malignancy that is very difficult to detect early, it is rarely cured (less than 1%) and even small tumors have often metastasized early to the liver. [10] This is preceded by release of circulating tumor cells (CTCs) which spread to the patients organs through the peripheral blood circulatory system. [11,49] Pancreatic CTCs can be used as a biomarker for potential earlier detection of cancer [12] however, there is no proven technology which could capture and detect these cells. [12-14] CTCs usually have oval shapes within the blood and there are size and shape differences between the pancreatic tumor cells and normal blood cells, which allows the latter to be selectively targeted by cell shape recognition. These features may potentially allow pancreatic CTCs to be extracted from blood samples by cell shape and size recognition using bioimprints produced for these specific types of cells. Available methods for the collection or detection of CTCs take advantage of various physical properties of the target cells and their surfaces. [15-24] Bioimprints have recently been recognized for their great potential for biomedical diagnostics and targeted therapies as they can effectively capture cells of specific shape and morphology, isolating them or delivering biocides directly to their surface. [25-27] Bioimprints are exact physical copies of the surface of a cell layer which can be produced by impressing the cells with a layer of curable polymer or other material. [25,27-29] The bioimprinting process produces a polymeric cast of the whole cell layer, producing a negative replica of the cells shape New techniques are required for earlier diagnosis and response to treatment of pancreatic cancer. Here, a label-free approach is reported in which circulating pancreatic tumor cells are isolated from healthy peripheral blood cells via cell bioimprinting technology. The method involves pre-fabrication of pancreatic cell layers and sequential casting of cell surfaces with a series of custom-made resins to produce negative cell imprints. The imprint is functionalized with a combination of polymers to engineer weak attraction to the cells which is further amplified by the increased area of contact with the matching cells. A flow-through bioimprint chip is designed and tested...