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Bandaru, Praveen; Cefaloni, Giorgia; Vajhadin, Fereshteh; Lee, KangJu; Kim, Han‐Jun; Cho, Hyun‐Jong; Hartel, Martin C.; Zhang, Shiming; Sun, Wujin; Goudie, Marcus J.; Ahadian, Samad; Dokmeci, Mehmet Remzi; Lee, Junmin; Khademhosseini, Ali

doi: 10.1002/smll.202001837pmid: 32419312

Stem cells secrete trophic factors that induce angiogenesis. These soluble factors are promising candidates for stem cell–based therapies, especially for cardiovascular diseases. Mechanical stimuli and biophysical factors presented in the stem cell microenvironment play important roles in guiding their behaviors. However, the complex interplay and precise role of these cues in directing pro‐angiogenic signaling remain unclear. Here, a platform is designed using gelatin methacryloyl hydrogels with tunable rigidity and a dynamic mechanical compression bioreactor to evaluate the influence of matrix rigidity and mechanical stimuli on the secretion of pro‐angiogenic factors from human mesenchymal stem cells (hMSCs). Cells cultured in matrices mimicking mechanical elasticity of bone tissues in vivo show elevated secretion of vascular endothelial growth factor (VEGF), one of representative signaling proteins promoting angiogenesis, as well as increased vascularization of human umbilical vein endothelial cells (HUVECs) with a supplement of conditioned media from hMSCs cultured across different conditions. When hMSCs are cultured in matrices stimulated with a range of cyclic compressions, increased VEGF secretion is observed with increasing mechanical strains, which is also in line with the enhanced tubulogenesis of HUVECs. Moreover, it is demonstrated that matrix stiffness and cyclic compression modulate secretion of pro‐angiogenic molecules from hMSCs through yes‐associated protein activity.

Khan, Shahid Ullah; Khan, Waheed Ullah; Khan, Wasim Ullah; Khan, Dilfaraz; Saeed, Sumbul; Badshah, Syed; Ikram, Muhammad; Saleh, Tawfik A.

doi: 10.1002/smll.202001551pmid: 32459055

The luminous efficiency of inorganic white light‐emitting diodes, to be used by the next generation as light initiators, is continuously progressing and is an emerging interest for researchers. However, low color‐rendering index (Ra), high correlated color temperature (CCT), and poor stability limit its wider application. Herein, it is reported that Sm3+‐ and Eu3+‐doped calcium scandate (CaSc2O4 (CSO)) are an emerging deep‐red‐emitting material with promising light absorption, enhanced emission properties, and excellent thermal stability that make it a promising candidate with potential applications in emission display, solid‐state white lighting, and the device performance of perovskite solar cells (PSCs). The average crystal structures of Sm3+‐doped CSO are studied by synchrotron X‐ray data that correspond to an extremely rigid host structure. Samarium ion is incorporated as a sensitizer that enhances the emission intensity up to 30%, with a high color purity of 88.9% with a 6% increment. The impacts of hosting the sensitizer are studied by quantifying the lifetime curves. The CaSc2O4:0.15Eu3+,0.03Sm3+ phosphor offers significant resistance to thermal quenching. The incorporation of lanthanide ion‐doped phosphors CSOE into PSCs is investigated along with their potential applications. The CSOE‐coated PSCs devices exhibit a high current density and a high power conversion efficiency (15.96%) when compared to the uncoated control devices.

doi: 10.1002/smll.202070139pmid: N/A

Madathiparambil Visalakshan, Rahul; González García, Laura E.; Benzigar, Mercy R.; Ghazaryan, Arthur; Simon, Johanna; Mierczynska‐Vasilev, Agnieszka; Michl, Thomas D.; Vinu, Ajayan; Mailänder, Volker; Morsbach, Svenja; Landfester, Katharina; Vasilev, Krasimir

Madathiparambil Visalakshan, Rahul; González García, Laura E.; Benzigar, Mercy R.; Ghazaryan, Arthur; Simon, Johanna; Mierczynska‐Vasilev, Agnieszka; Michl, Thomas D.; Vinu, Ajayan; Mailänder, Volker; Morsbach, Svenja; Landfester, Katharina; Vasilev, Krasimir

doi: 10.1002/smll.202000285pmid: 32406176

Nanoparticles have become an important utility in many areas of medical treatment such as targeted drug and treatment delivery as well as imaging and diagnostics. These advances require a complete understanding of nanoparticles' fate once placed in the body. Upon exposure to blood, proteins adsorb onto the nanoparticles surface and form a protein corona, which determines the particles' biological fate. This study reports on the protein corona formation from blood serum and plasma on spherical and rod‐shaped nanoparticles. These two types of mesoporous silica nanoparticles have identical chemistry, porosity, surface potential, and size in the y‐dimension, one being a sphere and the other a rod shape. The results show a significantly larger amount of protein attaching from both plasma and serum on the rod‐like particles compared to the spheres. Interrogation of the protein corona by liquid chromatography–mass spectrometry reveals shape‐dependent differences in the adsorption of immunoglobulins and albumin proteins from both plasma and serum. This study points to the need for taking nanoparticle shape into consideration because it can have a significant impact on the fate and therapeutic potential of nanoparticles when placed in the body.

Xiao, Dezhi; Ruan, Qingdong; Bao, De‐Liang; Luo, Yang; Huang, Chao; Tang, Siying; Shen, Jie; Cheng, Cheng; Chu, Paul K.

doi: 10.1002/smll.202001470pmid: 32463594

Plasma functionalization can increase the efficiency of MoSe2 in the hydrogen evolution reaction (HER) by providing multiple species but the interactions between the plasma and catalyst are not well understood. In this work, the effects of the ion energy and plasma density on the catalytic properties of MoSe2 nanosheets are studied. The through‐holes resulting from plasma etching and multi‐vacancies induced by plasma‐induced damage enhance the HER efficiency as exemplified by a small overpotential of 148 mV at 10 mA cm–2 and Tafel slope of 51.6 mV dec–1 after the plasma treatment using a power of 20 W. The interactions between the plasma and catalyst during etching and vacancies generation are evaluated by plasma simulation. Finite element and first‐principles density functional theory calculations are also conducted and the results are consistent with the experimental results, indicating that the improved HER catalytic activity stems from the enhanced electric field and more active sites on the catalyst, and reduced bandgap and adsorption energy arising from the etched through‐holes and vacancies, respectively. The results convey new fundamental knowledge about the plasma effects and means to enhance the efficiency of catalysts in water splitting as well insights into the design of high‐performance HER catalysts.

Bandaru, Praveen; Cefaloni, Giorgia; Vajhadin, Fereshteh; Lee, KangJu; Kim, Han‐Jun; Cho, Hyun‐Jong; Hartel, Martin C.; Zhang, Shiming; Sun, Wujin; Goudie, Marcus J.; Ahadian, Samad; Dokmeci, Mehmet Remzi; Lee, Junmin; Khademhosseini, Ali

Yu, Chenyang; An, Jianing; Zhou, Ruicong; Xu, Hai; Zhou, Jinyuan; Chen, Qiang; Sun, Gengzhi; Huang, Wei

doi: 10.1002/smll.202000653pmid: 32432831

Fiber‐based supercapacitors (FSCs) possess great potential as an ideal type of power source for future weaveable/wearable electronics and electronic‐textiles. The performance of FSCs is, without doubt, primarily determined by the properties of fibrous electrodes. Carbonaceous fibers, e.g., commercial carbon fibers, newly developed graphene fibers, and carbon nanotube fibers, are deemed as promising materials for weaveable/wearable supercapacitors owing to their exotic properties including high tensile strength and robustness, excellent electrical conductivity, good flexibility, and environmental stability. Nevertheless, bare carbonaceous fiber normally exhibits low capacitance originating from electric double‐layer capacitance, which remains unsatisfactory for efficiently powering wearable and portable devices. Numerous efforts have been devoted to tailoring fiber properties by hybridizing pseudocapacitive materials, and impressive progress has been achieved thus far. Herein, the microstructures of pristine carbonaceous fibers are introduced in detail, and the recent advances in rational nano/microstructure design of their hybrids, which provides the feasibility to achieve the synergistic interaction between conductive agents and pseudocapacitive nanomaterials but are normally overlooked, are comprehensively reviewed. Besides, the challenges in developing high‐performance fibrous electrodes are also elaborately discussed.

Kang, Dong Jin; Jüttke, Yvonne; González‐García, Lola; Escudero, Alberto; Haft, Marcel; Kraus, Tobias

doi: 10.1002/smll.202000928pmid: 32462772

Conductive inkjet printing with metal nanoparticles is irreversible because the particles are sintered into a continuous metal film. The resulting structures are difficult to remove or repair and prone to cracking. Here, a hybrid ink is used to obviate the sintering step and print interconnected particle networks that become highly conductive immediately after drying. It is shown that reversible conductive printing is possible on low‐cost cardboard samples after applying standard paper industry coats that are adapted in terms of surface energy and porosity. The conductivity of the printed films approaches that of sintered standard inks on the same substrate, but the mobility of the hybrid particle film makes them less sensitive to cracks during bending and folding of the substrate. Damages that occur can be partially repaired by wetting the film such that particle mobility is increased and particles move to bridge insulating gaps in the film. It is demonstrated that the conductive material can be recovered from the cardboard at the end of its life time and be redispersed to recycle the particles and reuse them in conductive inks.

Yang, Chen; Younis, Muhammad Rizwan; Zhang, Jing; Qu, Junle; Lin, Jing; Huang, Peng

doi: 10.1002/smll.202001518pmid: 32468633

Chemodynamic therapy (CDT) has attracted considerable attention recently, but the poor reaction kinetics restrict its practical utility in clinic. Herein, glucose oxidase (GOx) functionalized ancient pigment nanosheets (SrCuSi4O10, SC) for programmable near‐infrared II (NIR‐II) photothermal‐enhanced starvation primed CDT is developed. The SC nanosheets (SC NSs) are readily exfoliated from SC bulk suspension in water and subsequently functionalized with GOx to form the nanocatalyst (denoted as SC@G NSs). Upon laser irradiation, the photothermal effect of SC NSs can enhance the catalytic activity of GOx for NIR‐II photothermal‐enhanced starvation therapy, which effectively eliminates intratumoral glucose and produces abundant hydrogen peroxide (H2O2). Importantly, the high photothermal‐conversion efficiency (46.3%) of SC@G NSs in second biological window permits photothermal therapy of deep‐seated tumors under the guidance of NIR‐II photoacoustic imaging. Moreover, the acidity amplification due to gluconic acid generation will in turn accelerate the degradation of SC NSs, facilitating the release of strontium (Sr) and copper (Cu) ions. Both the elevated H2O2 and the released ions will prime the Cu2+/Sr2+‐H2O2 reaction for enhanced CDT. Thus, a programmable NIR‐II photothermal‐enhanced starvation primed CDT is established to combat cancer with minimal side effects.