A Magneto-Heated Silk Fibroin Scaffold for Anti-Biofouling Solar Steam Generation.

Macroscopic 3D porous materials are ideal solar evaporators for water purification. However, the limited sunlight intensity and penetrating depth during solar-driven evaporation cannot prevent the biofouling formation by photothermal effect, thus leading to the deterioration of evaporation rate. Herein, a magnetic heating strategy is reported for anti-biofouling solar steam generation based on a magnetic silk fibroin (SF) scaffold with bi-heating property. Under one sun, the solar-heated top surface of magnetic SF scaffolds accelerates water evaporation at 2.03 kg m-2 h-1 , while the unheated inner channels suffer from the formation of biofilm. When exposed to alternating magnetic field (AMF), the magnetic SF scaffold can be integrally heated, leading to an efficient inner temperature to prevent biofouling in channels for water transportation. Accordingly, magneto-heated scaffolds show steady water evaporation rates after exposure to S. aureus and E. coli, which maintained 93.6-94.6% of original performance. In contrast, the evaporation rates of the scaffolds without AMF treatment are reduced to 1.31 (S. aureus) and 1.32 (E. coli) kg m-2 h-1 , decreased by 35.5% and 35.0%, respectively. In addition, the magneto-heated scaffold inhibits biofouling formation in natural lake water, maintaining 99.5% original performance.

Self-assembling ferrimagnetic fluorescent micelles for bioimaging guided efficient magnetic hyperthermia therapy.

Multifunctional magnet-fluorescent nanocomposites are widely applied in biomedical applications. Incorporating biocompatible quantum dots with highly ferrimagnetic magnetic nanoparticles into one nanoplatform for achieving efficient magnetic hyperthermia therapy (MHT) is very important. Herein, we reported an amphiphilic block copolymer with a flowable hydrophobic chain to encapsulate highly ferrimagnetic magnetic nanoparticles and ZnS/InP quantum dots via a facile self-assembly method. The obtained ferrimagnetic fluorescent micelle (FMFM) exhibited a uniform diameter of about 180 nm. In stark contrast, larger aggregation (400 nm in diameter) inevitably occurred using common poly(D,L-lactide) (PLA)-based amphiphilic block copolymer with a rigid hydrophobic chain, which was readily cleared by the reticuloendothelial system (RES). The flowable FMFM exhibited long-term colloidal stability within one month and desired fluorescent stability within 84 h. Benefiting from the high ferrimagnetism, the FMFM revealed excellent magnetic heating effect and magnetic resonance imaging capability. With accurate manipulation under an external magnetic field, FMFM realized in vitro enhanced fluorescence imaging sensitivity and accumulation efficiency at the tumor region, achieving in vitro and vivo improved MHT efficacy.

Injectable magnetic montmorillonite colloidal gel for the postoperative treatment of hepatocellular carcinoma.

Bioactive materials have been extensively developed for the adjuvant therapy of cancer. However, few materials can meet the requirements for the postoperative resection of hepatocellular carcinoma (HCC) due to massive bleeding and high recurrence. In particular, combination therapy for HCC has been highly recommended in clinical practice, including surgical resection, interventional therapy, ablation therapy and chemotherapy. Herein, an injectable magnetic colloidal gel (MCG) was developed by controllable electrostatic attraction between clinically available magnetic montmorillonites and amphoteric gelatin nanoparticles. The optimized MCG exhibited an effective magnetic heating effect, remarkable rheological properties, and high gel network stability, realizing the synergistic treatment of postoperative HCC by stimuli-responsive drug delivery, hemostasis and magnetic hyperthermia. Furthermore, a minimal invasive MCG-induced interventional magnetic hyperthermia therapy (MHT) under ultrasound guidance was realized on hepatic tumor rabbits, providing an alternative therapeutics to treat the postoperative recurrence. Overall, MCG is a clinically available injectable formulation for adjuvant therapy after HCC surgical resection.

Oak-inspired anti-biofouling shape-memory unidirectional scaffolds with stable solar water evaporation performance.

Biomimetic porous materials have contributed to the enhancement of solar-driven evaporation rate in interfacial desalination and clean water production. However, due to the presence of numerous microbes in water environment, biofouling should occur inside porous materials to clog the channels for water transfer, resulting in obvious inhibition of the solar-driven evaporation efficacy in long-term use. To prevent and control biofouling in porous materials for solar-driven evaporation, a facile and environment-friendly design is required in real application. Oak wood possesses vertically aligned channels for transpiration and polyphenol compounds with antimicrobial activity. In this work, inspired by the oak wood, we developed an anti-biofouling shape-memory chitosan scaffold with unidirectional channels and tannic acid coating (oak-inspired scaffold). The shape-memory property facilitated rapid decoration with oak-inspired photothermal and anti-biofouling coating inside the scaffold, respectively, which also promotes the material durability by avoiding the external force-induced permanent structure failure. More importantly, the oak-inspired tannic acid coating not only prevented bacterial adhesion and colonization, but also inhibited fungal interference. They were subjected to a microbe-rich environment, and after 3 days, the evaporation rates of the untreated chitosan scaffolds were obviously decreased to 1.24, 1.16 and 1.19 kg m-2 h-1 for C. albicans, S. aureus and E. coli, respectively, which were only 65.6, 61.4 and 63.0% of original performance (1.89 kg m-2 h-1). In comparison, the oak-inspired scaffold exhibited a high solar-driven water evaporation rate after incubation in microbial suspensions (1.80, 1.70 and 1.75 kg m-2 h-1 for C. albicans, S. aureus and E. coli after 3 days) and lake water (1.74 kg m-2 h-1 after one month). The bioinspired anti-biofouling scaffolds maintain as high as 86.7-91.8% of the solar-driven water evaporation ability after exposure to a microbe-rich environment, which is conducive to develop a biomimetic long-term durable structure in water treatment.

A Magneto-Heated Ferrimagnetic Sponge for Continuous Recovery of Viscous Crude Oil.

The high viscosity and low fluidity of heavy crude oil hinder its sorption by conventional porous sorbents, so the efficient clean-up of such heavy crude oil spills is challenging. Recently, Joule heating has been emerging as a new tool to reduce the viscosity of heavy crude oil dramatically. However, this direct-contact heating approach presents a potential risk due to the high voltage applied. To develop a non-contact recovery of viscous crude oil, here, a new approach for the fabrication of a series of ferrimagnetic sponges (FMSs) with hydrophobic porous channels is reported, whose surface can be remotely heated to 120 °C within 10 s under an alternating magnetic field (f = 274 kHz, H = 30 kA m-1 ). Compared with the solar-driven superficial heating, the integral magnetic heating in FMSs can result in a higher internal temperature of the sponges because of the confinement of thermal transport in the porous channels, which contributes to a dramatic decrease in oil viscosity and a significant increase in oil flow into the pores of FMSs. Furthermore, FMSs assembled with a self-priming pump can achieve continuous recovery of viscous crude oil (33.05 g h-1 cm-2 ) via remotely magnetic heating.