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1.
Nat Commun ; 11(1): 1449, 2020 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-32193375

RESUMO

Pollen's practically-indestructible shell structure has long inspired the biomimetic design of organic materials. However, there is limited understanding of how the mechanical, chemical, and adhesion properties of pollen are biologically controlled and whether strategies can be devised to manipulate pollen beyond natural performance limits. Here, we report a facile approach to transform pollen grains into soft microgel by remodeling pollen shells. Marked alterations to the pollen substructures led to environmental stimuli responsiveness, which reveal how the interplay of substructure-specific material properties dictates microgel swelling behavior. Our investigation of pollen grains from across the plant kingdom further showed that microgel formation occurs with tested pollen species from eudicot plants. Collectively, our experimental and computational results offer fundamental insights into how tuning pollen structure can cause dramatic alterations to material properties, and inspire future investigation into understanding how the material science of pollen might influence plant reproductive success.


Assuntos
Ciência dos Materiais , Microgéis/química , Pólen/química , Biomimética/métodos , Química Computacional , Epitopos/química , Epitopos/imunologia , Esterificação , Dureza , Hidrólise , Hidróxidos/química , Microscopia de Fluorescência , Pectinas/química , Pectinas/imunologia , Pólen/imunologia , Polinização/fisiologia , Compostos de Potássio/química , Espectroscopia de Infravermelho com Transformada de Fourier
2.
Mater Sci Eng C Mater Biol Appl ; 62: 634-42, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26952467

RESUMO

Porous magnesium (Mg) has recently emerged as a promising biodegradable alternative to biometal for bone ingrowth; however, its low mechanical properties and high corrosion rate in biological environments remain problematic. In this study, porous magnesium was implemented in a scaffold that closely mimics the mechanical properties of human bones with a controlled degradation rate and shows good biocompatibility to match the regeneration rate of bone tissue at the affected site. The alumina-reinforced Mg scaffold was produced by spark plasma sintering and coated with magnesium fluoride (MgF2) using a hydrofluoric acid solution to regulate the corrosion rate under physiological conditions. Sodium chloride granules (NaCl), acting as space holders, were leached out to achieve porous samples (60%) presenting an average pore size of 240 µm with complete pore interconnectivity. When the alumina content increased from 0 to 5 vol%, compressive strength and stiffness rose considerably from 9.5 to 13.8 MPa and from 0.24 to 0.40 GPa, respectively. Moreover, the biological response evaluated by in vitro cell test and blood test of the MgF2-coated porous Mg composite was enhanced with better corrosion resistance compared with that of uncoated counterparts. Consequently, MgF2-coated porous Mg/alumina composites may be applied in load-bearing biodegradable implants.


Assuntos
Óxido de Alumínio/química , Materiais Biocompatíveis/química , Fluoretos/química , Compostos de Magnésio/química , Animais , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Força Compressiva , Corrosão , Hemólise/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Teste de Materiais , Camundongos , Microscopia Eletrônica de Varredura , Porosidade , Difração de Raios X
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