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Histone deacetylase (HDAC) proteins are promising targets for cancer treatment, with several HDAC inhibitors used clinically as anticancer drugs. Most HDAC inhibitors nonspecifically interact with all or many of the 11 HDAC isoforms. Isoform-selective HDAC inhibitors would be useful tools to dissect the individual functions of HDAC proteins in cancer formation, in addition to potentially displaying effective anticancer properties. We report here a robust HDAC activity assay for screening selective HDAC inhibitors, which is inspired by the traditional enzyme-linked immunosorbent assay (ELISA). The key feature of the ELISA-based HDAC activity assay is use of mammalian cell-derived HDAC isoforms instead of recombinant proteins. Importantly, the assay was validated with several known HDAC inhibitors. The ELISA-based HDAC activity assay will facilitate the characterization of isoform-selective HDAC inhibitors against mammalian cell-derived HDAC proteins, which will enhance HDAC-centered cancer research and provide a foundation for anticancer drug development.

A new ferrofluidic droplet generator is demonstrated using an electropermanent magnet to change the viscosity of the ferrofluid oil phase in a flow-focusing junction, which enables control of the aqueous droplet size. Electropermanent magnets are capable of fast switching (< 100 $$\upmu$$μs) and have magnetic field strengths comparable to those of permanent magnets. When switched on, the magnetoviscous effect increases the viscosity of the ferrofluid, thus increasing the channel’s fluidic resistance, slowing the flow rate of the oil-based phase and changing the droplet diameter. We have demonstrated on-demand droplet size modulation as large as 44% at speeds fast enough to modulate the size of a single droplet in a stream. Due to compliance in the supply tubing and Polydimethylsiloxane (PDMS) microfluidic channels, the change in droplet size relaxes with a time scale of seconds. An application of droplet size modulation was demonstrated by integrating a passive size-based magnetic droplet sorting stage.

BACKGROUND: The only curative procedure to date for liver tumors is surgical resection, which remains a major procedure with marked morbidity and mortality. Radiofrequency (RF) has increasingly been used for both ablation and resection. On the basis of this technique, a new bipolar RF device, Habib 4X, has been developed and used clinically. We present our technique of liver resection with this device in a patient with colorectal liver metastases.

METHODS: A patient with situs inversus who had colorectal liver metastases in her left lobe underwent left lateral segmentectomy with the new device, a four-electrode bipolar resection device that uses RF energy for tissue necrosis. After laparotomy and intraoperative ultrasound, the plane resection was marked 1 cm away from the edge of the lesion. Coagulative desiccation was performed along this plane using this sealer connected to a RF generator. The necrosed band of parenchyma was then divided with a scalpel and resection completed.

RESULTS: The length of the procedure was 105 minutes; resection time was 35 minutes. Total blood loss was 100 ml. No blood transfusions were required, and the patient was not admitted to the intensive care unit after surgery. The patient was discharged 10 days after surgery without any surgical complications.

CONCLUSIONS: We think that RF-assisted liver resection with this new device is safe and effective. It is quicker than conventional RF and may reduce overall hospital stay in liver resection patients.