Weibo Cai

My research primarily focuses on three areas: 1) Development of novel molecular imaging agents (mainly PET, MRI, photoacoustic, fluorescence, and bioluminescence) for early diagnosis of certain diseases, such as cancer and diabetes, and monitoring the efficacy of therapeutic intervention; 2) Biomedical applications of various nanomaterials (e.g. imaging, image-guided drug delivery, cancer therapy, and theranostics); and 3) Development of novel molecularly targeted therapeutic agents. In a paper published in Diabetes in 2017, we showed that positron emission tomography (PET) is advantageous for determining functional β-cell mass using 52Mn2+ (t1/2: 5.6 days). We investigated the whole-body distribution of 52Mn2+ in healthy adult mice by dynamic and static PET imaging. Pancreatic voltage-dependent calcium channel (VDCC) uptake of 52Mn2+ was successfully manipulated pharmacologically in vitro and in vivo using glucose, nifedipine (VDCC blocker), the sulfonylureas tolbutamide and glibenclamide (KATP channel blockers), and diazoxide (KATP channel opener). In a mouse model of streptozotocin-induced type 1 diabetes, 52Mn2+ uptake in the pancreas was distinguished from healthy controls in parallel with classic histological quantification of β-cell mass from pancreatic sections. 52Mn2+-PET also reported the expected increase in functional β-cell mass in the ob/ob model of pretype 2 diabetes, a result corroborated by histological β-cell mass measurements and live-cell imaging of β-cell Ca2+ oscillations. These results indicate that 52Mn2+-PET is a sensitive new tool for the noninvasive assessment of functional β-cell mass. Subsequently we also reported the use of Mn-51 chloride (half-life: 46 minutes) for similar applications (2017 Scientific Reports). We are currently translating 51MnCl2 into human studies for beta-cell imaging.