Digital Microfluidics with an On-Chip Drug Dispenser for Single or Combinational Drug Screening

Rapid and accurate cancer drug screening is of great importance in precision medicine. However, the limited amount of tumor biopsy samples has hindered the application of traditional drug screening methods with microwell plates for individual patients. A microfluidic system provides an ideal platform for handling trace amounts of samples. This emerging platform has a good role in nucleic acid-related and cell related assays. Nevertheless, convenient drug dispensing remains a challenge for clinical on-chip cancer drug screening. Similar sized droplets are merged to add drugs for a desired screened concentration which significantly complicated the on-chip drug dispensing protocols. Here, we introduce a novel digital microfluidic system with a specially structured electrode (a drug dispenser) to dispense drugs by droplet electro-ejection under a high-voltage actuation signal, which can be conveniently adjusted by external electric controls. With this system, the screened drug concentrations span up to four orders of magnitude with small sample consumption. Various amounts of drugs can be delivered to the cell sample with desired amount in a flexible electric control. Moreover, single drug or combinatorial multidrug on-chip screening can be readily achieved. The drug response of normal MCF-10A breast cells and MDA-MB-231 breast tumor cells to two chemotherapeutic substances, cisplatin (Cis) and epirubicin (EP), was tested individually and in combination for proof-of-principle verification. The comparable on-chip and off-chip results confirmed the feasibility of our innovative DMF system for cancer drug screening.

and Musa acuminata extracts to attenuate 4-hydroxyestradiol (4-OHE2 )-induced DNA oxidative damage in MCF-10A cells by upregulating detoxifying and antioxidant enzymes

Nowadays, there have been attempts to use phytochemicals in fruits to reduce the risk of suffering a given sickness. In this work, we studied the potential effects of mango (cultivar "Nam Dok Mai") and banana (cultivar "Khai") to attenuate DNA oxidative damage in MCF-10A cells induced by 4-hydroxyestradiol (4-OHE₂ ). The effects of mango extract (MNE) and banana extract (BKE) were comparable with three carotenoid compounds, β-carotene, lycopene, and lutein. The oxidative-induced DNA damage was evaluated by 8-hydroxy-2-deoxyguanosine (8-OHdG) reduction. 4-OHE₂ -induced DNA oxidative damage in MCF-10A cells showed a decrease in 8-OHdG formation when treated with MNE and BKE. Both fruit extracts also enabled the regaining production of Phase II detoxifying (GSTs and NQO1) and antioxidant (SOD, GPx, and CAT) enzymes during 4-OHE₂ -induced DNA oxidative damage in the MCF-10A cells when compared with the untreated control. These results indicate that MNE and BKE can exert potential mitigating effects against 4-OHE₂ -induced DNA oxidative damage in MCF-10A cells by enhancing the activities of detoxifying and antioxidant enzyme. PRACTICAL APPLICATIONS: Long-term exposure to estrogen increases the risk of sickness since oxidative stress via the estrogen pathway, leading to DNA damage. This study indicated that mango (cultivar "Nam Dok Mai") extract contains β-carotene and lycopene, while banana (cultivar "Khai") extract contains β-carotene and lutein, which act as natural antioxidants. Both fruit extracts have preventive properties against oxidative DNA damage and are potentially good supplements for women taking E₂ between HRT.