Nanocatalytic medicine has emerged as a promising method for the specific cancer therapy by mediating the interaction between tumor microenvironment biomarkers and nanoagents. However, the produced antitumor cell killing molecules, such as reactive oxygen species (ROS), by catalysis are insufficient to inhibit tumor growth. Herein, a novel kind of polyvinyl pyrrolidone modified multifunctional iron sulfide nanoparticles (Fe1−xS‐PVP NPs) is developed via a one‐step hydrothermal method, which exhibits high photothermal (PT) conversion efficiency (η = 24%) under the irradiation of 808 nm near‐infrared laser. The increased temperature further facilitates the Fenton reaction to generate abundant •OH radicals. More importantly, under an acidic (pH = 6.5) condition within tumor environment, the Fe1−xS‐PVP NPs can in situ produce H2S gas, which is evidenced to suppress the activity of enzyme cytochrome c oxidase (COX IV) in cancer cells, contributing to inhibit the growth of tumor. Both in vitro and in vivo results demonstrate that the H2S‐mediated gas therapy in combination with PT enhanced ROS achieves excellent antitumor performance, which can open up a new approach for the design of gas‐mediated cancer treatment.

The blood–brain barrier (BBB) is the most important obstacle to improving the clinical outcomes of diagnosis and therapy of glioblastoma. Thus, the development of a novel nanoplatform that can efficiently traverse the BBB and achieve both precise diagnosis and therapy is of great importance. Herein, an intelligent nanoplatform based on holo‐transferrin (holo‐Tf) with in situ growth of MnO2 nanocrystals is constructed via a reformative mild biomineralization process. Furthermore, protoporphyrin (ppIX), acting as a sonosensitizer, is then conjugated into holo‐Tf to obtain MnO2@Tf‐ppIX nanoparticles (TMP). Because of the functional inheritance of holo‐Tf during fabrication, TMP can effectively traverse the BBB for highly specific magnetic resonance (MR) imaging of orthotopic glioblastoma. Clear suppression of tumor growth in a C6 tumor xenograft model is achieved via sonodynamic therapy. Importantly, the experiments also indicate that the TMP nanoplatform has satisfactory biocompatibility and biosafety, which favors potential clinical translation.

Depth resolved and en face OCT visualization in vivo may have important clinical applications in endoscopy. We demonstrate a high speed, two-dimensional (2D) distal scanning capsule with a micromotor for fast rotary scanning and a pneumatic actuator for precision longitudinal scanning. Longitudinal position measurement and image registration were performed by optical tracking of the pneumatic scanner. The 2D scanning device enables high resolution imaging over a small field of view and is suitable for OCT as well as other scanning microscopies. Large field of view imaging for screening or surveillance applications can also be achieved by proximally pulling back or advancing the capsule while scanning the distal high-speed micromotor. Circumferential en face OCT was demonstrated in living swine at 250 Hz frame rate and 1 MHz A-scan rate using a MEMS tunable VCSEL light source at 1300 nm. Crosssectional and en face OCT views of the upper and lower gastrointestinal tract were generated with precision distal pneumatic longitudinal actuation as well as proximal manual longitudinal actuation. These devices could enable clinical studies either as an adjunct to endoscopy, attached to an endoscope, or as a swallowed tethered capsule for non-endoscopic imaging without sedation. The combination of ultrahigh speed imaging and distal scanning capsule technology could enable both screening and surveillance applications. Kimmey

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Rationale : Ferritin with unique hollow cavity is an emerging protein-based nanoplatform for anticancer-drug delivery, but the in vivo chemotherapeutic effectiveness is still unsatisfactory with such a monotherapy modality, which is urgently in need of improvement. Methods : Here a novel ferritin nanotheranostic with anticancer-drug doxorubicin encapsulated into its hollow interior and nanoradiosensitizer bismuth sulfide nanocrystals inlayed onto its polypeptide shell was synthesized for combinational therapeutic benefits. The formation mechanism of bismuth sulfide nanocrystals based on ferritin has been analyzed. The in vitro and in vivo treatment effects were carried out on HeLa cancer cells and tumor-bearing mice, respectively. The biocompatibility and excretion of the ferritin nanotheranostic have also been evaluated to guarantee their biosafety. Results : The polypeptide shell of ferritin provides nucleation sites for the bismuth sulfide nanocrystals through coordination interaction, and simultaneously inhibits the further growth of bismuth sulfide nanocrystals, rendering the bismuth sulfide nanocrystals like rivets inlaying onto the polypeptide firmly, which can not only strengthen the architectural stability of ferritin to prevent drug burst leakage during systemic circulation, but also act as excellent computed tomography contrast agents and nanoradiosensitizers for in vivo imaging-guided cancer combinational treatments. Conclusions : The design concept of inlaying bismuth sulfide nanocrystals onto the polypeptide shell of doxorubicin-encapsulated ferritin significantly inhibits the tumor growth and simultaneously further broadens the application of ferritin in nanomedicine.

Redox homeostasis is vital for cell survival. Nowadays, developing novel nanoagents that can efficiently break the redox homeostasis, which includes improving the reactive oxygen species level while reducing the glutathione (GSH) level, has emerged as a promising but challenging strategy for tumor therapy. In this work, a novel albumin-based multifunctional nanoagent is developed for GSH-depletion assisted chemo-/chemodynamic combination therapy. Briefly, CuO and MnO X are in situ co-grown inside the albumin molecules through a facile biomineralization process, followed by the conjugation of Pt (IV) prodrug to obtain the final nanoagent. Thereinto, copper species can produce •OH with optimal efficiency under weakly acidic conditions (pH = 6.5), while MnO X can react with GSH, leading to the GSH depletion, which reduces the formation of GSH-Pt adducts and •OH consumption, thus favoring a better chemotherapy and chemodynamic therapy effect, respectively. Significantly, both GSH depletion and •OH generation contributes to the inhibited expression of GPX-4, which further increases the oxidative stress. Moreover, during the reaction between MnO X and GSH or H 2 O 2 , Mn 2+ ions are released for MR imaging while O 2 is produced for hypoxia relief. It is believed that the proposed strategy can provide a new perspective on effective tumor therapy.

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Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of conventional OCT and can assess depth-resolved tissue birefringence in addition to intensity. Most existing PS-OCT systems are relatively complex and their clinical translation remains difficult. We present a simple and robust all-fiber PS-OCT system based on swept source technology and polarization depth-encoding. Polarization multiplexing was achieved using a polarization maintaining fiber. Polarization sensitive signals were detected using fiber based polarization beam splitters and polarization controllers were used to remove the polarization ambiguity. A simplified post-processing algorithm was proposed for speckle noise reduction relaxing the demand for phase stability. We demonstrated systems design for both ophthalmic and catheter-based PS-OCT. For ophthalmic imaging, we used an optical clock frequency doubling method to extend the imaging range of a commercially available short cavity light source to improve polarization depth-encoding. For catheter based imaging, we demonstrated 200 kHz PS-OCT imaging using a MEMS-tunable vertical cavity surface emitting laser (VCSEL) and a high speed micromotor imaging catheter. The system was demonstrated in human retina, finger and lip imaging, as well as ex vivo swine esophagus and cardiovascular imaging. The all-fiber PS-OCT is easier to implement and maintain compared to previous PS-OCT systems and can be more easily translated to clinical applications due to its robust design. Aretz, E. F. Halpern, and B. E. Bouma, "In vivo characterization of coronary atherosclerotic plaque by use of optical coherence tomography," Circulation 111(12), 1551-1555 (2005).