Toward Rational Design of Carbon Nanodots with High Photothermal Efficiency for Tumor Photothermal Therapy

Comprehensive Summary Carbon nanodots(CDs)with high photothermal performance are ideal candidates for tumor photothermal therapy(PTT).Herein,we investigated the photothermal performance of CDs synthesized from urea and citric acid via solvothermal method in dimethyl sulfoxide(DMSO)at different temperatures.Photothermal conversion efficiency(PCE)of up to 61.3%was obtained in the CDs synthesized at 150℃(150-CDs),which is much better than the CDs synthesized at 180℃(180-CDs).By analyzing the morphologies,chemical structures,and absorption spectra of these CDs,we found that the photothermal effect of the CDs was due to the lattice vibration of their carbonized cores.

Rodlike nanomaterials from organic diradicaloid with high photothermal conversion capability for tumor treatment

Organic diradicaloids with unique open-shell structures and properties have been widely used in organic electronics and spintronics.However,their advantageous optical properties have been explored less in the biomedical field.In this work,the photothermal conversion behaviors of a boron-containing organic diradicaloid(BOD)are reported.BOD can assemble with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol)to form rodlike nanoparticles(BOD NPs).These as-prepared BOD NPs exhibit high photothermal conversion capability and robust photothermal stability.Notably,they possess morphological superiority,which guarantees the effective photothermal therapy of tumors.This work thus demonstrates the promise of organic diradicaloids as efficient photothermal agents for biomedical applications.

Preparation and properties of substrate PVA-GO composite membrane for solar photothermal conversion

Solar thermal desalination(STD)is a promising and sustainable technology for extracting clean water resources.Whereas recent studies to improve STD performance primarily focus on interfacial solar evaporation,a non-traditional bottom heating method was designed in this study.Herein,we prepared the polyvinyl alcohol/graphene oxide(PVA-GO)composite membrane and adhered to the bottom of a beaker using crystallized PVA.The GO was loaded on a non-woven fabric and different concentrations of PVA were compared for their effect on the evaporation efficiency.The results showed that the addition of PVA increased the evaporation rate.The surface characteristic of GO membrane without PVA was a fibrous filamentous structure as observed by SEM,whereby the fibers were clearly visible.When the PVA concentration reached 6%,the non-woven fiber was completely wrapped by PVA.Under the action of a fixed light intensity,the photothermal conversion rates of GO,2%PVA-GO,4%PVA-GO and 6%PVA-GO membrane device could reach 39.93%,42.61%,45.10%and 47.00%,respectively,and the evaporation rates were 0.83,0.88,0.94 and 0.98 kg$m-2$h-1,respectively.In addition,the PVA-GO composite membrane showed an excellent stability,which has significance for industrial application.

High-Performance Natural Melanin/Poly(vinyl Alcohol-co-ethylene) Nanofibers/PA6 Fiber for Twisted and Coiled Fiber-Based Actuator

Twisted and coiled fiber-based actuators have drawn a great attention because their unique structure can provide mechanical response with the external thermal stimulus.Herein,an ultra-fast and light-weight twisted and coiled fiber-based actuator was designed based on a nature melanin/poly(vinyl alcohol-co-ethylene)(PVA-co-PE)nanofibers/PA6 composite fiber.In brief,PA6 was firstly coated by melanin/PVA-co-PE nanofibers using a spraying method,followed by the twisting and coat-ing the composite fiber to obtain the actuator.The excellent photothermal property of melanin contributed to the superior performance of the actuator,whereas the PVA-co-PE nanofibers was responsible for the uniform distribution of melanin and the enhanced mechanical property of the prepared-actuator.This unique design has led to the high performance of the melanin/NFs/PA6 fiber-based actuator,whose torsion actuation can reach to 14,000 rpm,and maximum tensile actuation was−6.36%at temperature difference of 40℃.In addition,the tensile stress of PA6/NFs/melanin fiber was about four times higher than PA6 filaments.Owing to the simple and environmental-benign preparation method,as well as the excellent effi-ciency of twisted and coiled melanin/NFs/PA6 fiber-based actuator,this study highlights the facile design of the composite fiber for high-performance fiber-based actuators.This fiber-based actuator is promising for application in energy generator.

A review of high-temperature selective absorbing coatings for solar thermal applications

Solar selective absorbing coatings directly harvest solar energy in the form of heat.The higher temperatures are required to drive higher power-cycle efficiencies in favor of lower costs of energy.According to different dielectrics,high temperature coatings can mainly be divided to double cermet solar selective coatings,transition metal nitride multilayer coatings and transition metal oxide multilayer coatings.This paper assesses the photothermal conversion efficiency and thermal stability,and discusses the challenges and strategies of improving both thermal and optical properties.Double cermet layers can stabilize nanocrystalline structures by alloying,while transition metal nitride/oxide layers generally choose the reliable materials with superior mechanical properties and thermal stability.The purpose of this review is to get the optimized systems,and propose further research directions at higher temperature,such as all-ceramic absorbing coatings.

Controllable synthesis of layered black bismuth oxidechloride nanosheets and their applications in internal tumor ablation

The recently emerging bismuth oxyhalide(BiOX)nanomaterials are promising indirect band gap photosensitizer for ultraviolet(UV)light-triggered phototherapy due to their unique layered nanosheet structure.However,the low absorption and poor photothermal conversion efficiency have always impeded their further applications in cancer clinical therapy.Herein,BiOCl rich in oxygen vacancies has been reported to have fullspectrum absorption properties,making it possible to achieve photothermal property under near-infrared laser.Under 808nm irradiation,the photothermal conversion efficiency of black BiOCl nanosheets(BBNs)is up to 40%.BBNs@PEG can effectively clear primary subcutaneous tumors and prevent recurrence,achieving good synergistic treatment effect.These results not only broke the limitation of UV on the BiOCl material and provided a good template for other semiconductor materials,but also represent a promising approach to fabricate BBN@PEG a novel,potent and multifunctional theranostic platform for precise photothermal therapy and prognostic evaluation.

Polymerization-Amplified Photoacoustic Signal by Enhancing Near-Infrared Light-Harvesting Capacity and Thermal-to-Acoustic Conversion

As a frontier imaging technique for biomedical applications,photoacoustic(PA)imaging has been developed rapidly.The development of new design strategies and excellent PA imaging reagents to boost PA conversion is eagerly desirable for high quality PA imaging but complicated to realize.Herein,we develop a new strategy in which PA imaging reagents with better properties can be easily optimized by polymerization.A series of new PA imaging reagents were designed and synthesized.The polymerization strategy can effectively promote the PA signal by specifically increasing the thermal-to-acoustic conversion efficiency.As these materials shared the same building units,the optimized effectiveness of polymerization strategy in terms of near-infrared light-harvesting capacity and thermal-to-acoustic conversion efficiency are discussed,rationally.The polymers with intense intramolecular motion exhibit an amplified PA signal by elevating thermal-to-acoustic conversion and its higher light-harvesting capability at redshifted region.The simultaneously strong PA signal and photothermal conversion efficiency of p-TTmB NPs enable precise PA imaging and effective photothermal therapy.This work highlights a simple and available design guideline of polymerization for amplifying the PA effect and optimizing existing materials.